SEPTEMBER 1979 Volume 4, Number 9 $2.00 in .0 in Canada the small systems journal ^ A MCGRAW-HILL PUBLICATION If you have a problem that can be solved by a computer— we have a systems solution. * Two central processors with maximum RAM capacities of 56K and 384 K bytes * Three types of disk drives with capacities of 175K, 1 .2M and 16M bytes * Two dot matrix printers with 80 and 132 line capacity A Selectric typewriter interface and a daisy wheel printer Match these to your exact need, add one or more of our intelligent terminals and put together a system from one source with guaranteed compatibility in both software and hardware. Southwest Technical Products systems give you unmatched power, speed and versatility. They are packaged in custom designed woodgrain finished cabinets. Factory service and support on the entire system and local service is available in many cities. SOUTHWEST TECHNICAL PRODUCTS CORPORATION 219 W. RHAPSODY SAN ANTONIO, TEXAS 78216 (512) 344-0241 Circle 356 on inquiry card. Low-cost hard disk computers are here 11 megabytes of hard disk and 64 kilobytes of fast RAM in a Z80A computer for under $10K. Two floppy drives, too. Naturally, it's from Cromemco. It's a reality. In Cromemco's new Model Z-2H you get all of the above and even more. With Cromemco you get it all. In this new Model Z-2H you get not only a large-storage Winchester hard disk drive but also two floppy disk drives. In the hard disk drive you get unprecedented storage capacity at this price — 11 megabytes unfor- matted. You get speed — both in the 4 MHz Z80A microprocessor and in the fast 64K RAM which has a chip access time of only 150 nanoseconds. You get speed in the computer minimum instruction execution time of 1 micro- second. You get speed in the hard disk transfer rate of 5.6 megabits/sec. EXPANDABILITY You get expandability, too. The high-speed RAM can be expanded to 512 kilobytes if you wish. And the computer has a full 12-slot card cage you can use for additional RAM and interface cards. BROADEST SOFTWARE SUPPORT With the Z-2H you also get the broadest software support in the microcomputer field. Software Cro- memco is known for. Software like this: • Extended BASIC • FORTRAN IV • RATFOR (RATional FORtran) • COBOL • Z80 Macro Assembler • Word Processing System • Data Base Management with more coming all the time. SMALL, RUGGED, RELIABLE With all its features the new Z-2H, including its hard disk drive, is still housed in just one small cabinet. Included in that cabinet, too, is Cromemco ruggedness and reliability. Cromemco is time-proved. Our equipment is a survey winner for reliability. Of course, there's Cro- memco's all-metal cabinet. Rugged, solid. And, there's the heavy-duty power supply (30A @ 8V, 15A @ + 18 V, and 15A @ -18V) for cir- cuitry you'll sooner or later want to plug into those free card slots. CALL NOW With its high performance and low price you KNOW this new Z-2H is going to be a smash. Look into it right now. Contact your Cromemco computer store and get our sales literature. Find out when you can see it. Many dealers will be showing the Z-2H soon — and you'll want to be there when they do. ra Hard disk drive at lower left can be inter- changed just by sliding out and disconnecting plug. Seven free card slots are available. Z-2H includes printer interface card. Cromemco PRESENT CROMEMCO USERS We've kept you in mind, too. Ask about the new Model HDD Disk Drive which can combine with your present Cromemco computer to give you up to 22 megabytes of disk storage. Circle 80 on inquiry card. •^^^J 280 BERNARDO AVE., MOUNTAIN VIEW, CA 94040 ^^* Tomorrow's computers now (415)964-7400 BYTE September 1979 Latched Outputs 4 MHz Crystal Clock On Card Voltage Regulation Parallel I/O Port #1 \ Parallel I/O Port #2 / Parallel I/O Port #3 \ RS-232 or Current Loop I/O Port #4 8KROM Capacity IK RAM Standard Bus for System Expandability Programmable Baud Rate UARTwith Interval Timers 4 MHz Z-80A Completely Buffered Bus Interface The single card computer with the features that help you in real life COMPLETE COMPUTER In this advanced card you get a pro- fessional quality computer that meets today's engineering needs. And it's one that's complete. It lets you be up and running fast. All you need is a power supply and your ROM software. The computer itself is super. Fast 4 MHz operation. Capacity for 8K bytes of ROM (uses 2716 PROMs which can be programmed by our new 32K BYTE- SAVER® PROM card). There's also 1K of on-board static RAM. Further, you get straightforward interfacing through an RS-232 serial interface with ultra-fast speed of up to 76,800 baud — software programmable. Other features include 24 bits of bi- directional parallel I/O and five on- board programmable timers. Add to that vectored interrupts. ENORMOUS EXPANDABILITY Besides all these features the Cro- memco single card computer gives you enormous expandability if you ever need it. And it's easy to expand. First, you can expand with the new Cromemco 32K BYTESAVER PROM card mentioned above. Then there's Cromemco's broad line of S100-bus-compatible memory and I/O interface cards. Cards with fea- tures such as relay interface, analog interface, graphics interface, opto- isolator input, and A/D and D/A con- version. RAM and ROM cards, too. Card Cage 32K BYTESAVER PROM card EASY TO USE Another convenience that makes the Model SCC computer easy to use is our Z-80 monitor and 3K Control BASIC (in two ROMs). With this optional software you're ready to go. The monitor gives you 12 commands. The BASIC, with 36 commands/functions, will directly ac- cess I/O ports and memory locations — and call machine language subroutines. Finally, to simplify things to the ulti- mate, we even have convenient card cages. Rugged card cages. They hold cards firmly. No jiggling out of sockets. AVAILABLE NOW/ LOW PRICE The Cromemco Model SCC is avail- able now at a low price of only $450 factory assembled ($395 kit). So act today. Get this high-capability computer working for you right away. G Cromemco incorporated Specialists in computers and peripherals 280 BERNARDO AVE., MOUNTAIN VIEW, CA 94040 (415) 964-7400 2 BYTE September 1979 Circle 80 on inquiry card. In The Cue we BITI September 1979 Volume 4, Number 9 Foreground 10 20 34 70 96 118 130 62 84 160 182 196 JOYSTICK INTERFACES by Steve Ciarcia An interface for every purpose INTRODUCTION TO MULTIPROGRAMMING by Mark Dahmke Some basic concepts INTERFACE A CHESSBOARD TO YOUR KIM-1 by Jeff Teeters Play chess with a computer as easily as with a human opponent A LOW-SPEED ANALOG-TO-DIGITAL CONVERTER by Richard C Hallgren Perform real-time data analysis THE NATURE OF ROBOTS, Part 4 by William T Powers A simple, human experiment INEXPENSIVE, OPTICAL PAPER-TAPE READER by Brian A Harron A manual paper-tape reader with no moving parts A MODEL OF THE BRAIN FOR ROBOT CONTROL, Part 4 by James Albus Decision-making procedures Background page JO SOME MUSINGS ON HARDWARE DESIGN by Clayton Ellis Simple design techniques SOLDERING TECHNIQUES by William Trimmer A picture essay HANDY PULSER by Bob Chrisp A simple, circuit-debugging tool THE AMSAT-GOLEM-80 by Joe Kasser A modular and inexpensive S-100 computer system ADD SOME CONTROL TO YOUR COMPUTER by Ken Barbier Let your computer influence the outside world Nucleus Editorial: The Rationale of Yet Another Homebrew System 6 Programming Quickies 58,126 Unclassified Ads 61 BYTE's Bits 80 Technical Forum 82 Clubs and Newsletters 92 BYTE News 115 Book Reviews 122, 152 Letters 150 Languages Forum 164 Event Queue 176 What's New? 214 Reader Service 256 BOMB 256 page 34 Cover Art: Fantasy on Homebrewing by Robert Tinney. BYTE is published monthly by BYTE Publications Inc. 70 Main St, Peterborough NH 03458, a wholly-owned subsidiary of McGraw-Hill, Inc. Address all mail except subscriptions to above address: phone (603) 924-7217. Address subscriptions, change of address, USPS Form 3579, and fulfillment questions to BYTE Subscriptions, PO Box 590, Martinsville NJ 08836. Second class postage paid at Peterborough NH 03458 and at additional mailing offices— USPS Publication No. 102410 (ISSN 0360-5280). Subscriptions are $18 for one year, $32 for two years, and $46 for three years in the USA and its possessions. In Canada and Mexico, $20 for one year, $36 for two years, $52 for three years. $32 for one year air delivery to Europe. $32 surface delivery elsewhere. Air delivery to selected areas at additional rates upon request. Single copy price is $2 in the USA and its possessions, $2.40 in Canada and Mexico, $3.50 in Europe, and $4 elsewhere. Foreign subscriptions and sales should be remitted in United States funds drawn on a US bank. Printed in United States of America. Address all editorial correspondence to the editor at the above address. Unacceptable manuscripts will be returned if accompanied by sufficient first class postage. Not responsible for lost manuscripts or photos. Opinions expressed by the authors are not necessarily those of BYTE. Entire contents copyright © 1979 by BYTE Publications Inc. All rights reserved. BYTE's is available in microform from University Microfilms International. 300 N Zeeb Rd, Dept PR. Ann Arbor Ml 48106 USA or 18 Bedford Row, Dept PR, London WC1R 4EJ ENGLAND. Subscription WATS Line: (800) 258-5485 Office hours: Mon-Thur 8:30 AM - 4:30 PM Friday 8:30 AM - Noon September 1979 © BYTE Publications Inc 3 About the Cover On this issue's cover, Robert Tinney has created a "fantasy on homebrewing. " In the middle of a sylvan glade, we see the form of a computer being sculpted by some homebrewer. A couple of humanoid forest denizens look on with wonder, perhaps hoping to get a glimpse of our home- brewer on his return to the work- place. Building a joystick in- terface for your computer system adds a new physical input dimension. There are as many dif- ferent ways to interface a joystick as there are ap- plications. Steve Ciarcia discusses several widely varying ways to design Joystick Interfaces. Page 10 The idea of having a microcomputer work in a multiprogramming en- vironment is becoming a reality. Already there are several multiprogram- ming systems on the market. Mark Dahmke provides an Introduction to Multiprogramming so we can understand how these systems operate. Page 20 If you enjoy playing chess against your com- puter, but dislike typing in the moves in abstract notation, you will be in- terested in a method of allowing the computer to detect moves made on a real chessboard. Jeff Teeters devised such a method and now tells us how he did it in Interface a Chessboard to Your KIM-1. Page 34 Some Musings On Hardware Design by Clayton Ellis provides readers with background information on picking integrated circuits and using them in homebrew work. Page 62 Although there are many applications where a high-speed analog-to- digital converter is necessary, many conver- sion applications can make do with a slower conversion. Richard C Hallgren has built A Low-Speed Analog-to- Digital Converter for the Apple II which he uses as a real-time data analyzer. Page 70 When constructing electronic equipment, it is imperative that good Soldering Techniques are developed. William Trim- mer presents a photo essay of good soldering practices and several ex- amples of unwanted techniques. Page 84 William T Powers brings his discussion of The Nature of Robots to a close by applying the previously-discussed techniques and theories in a simple experiment with a human subject. Page 96 The search for the in- expensive paper-tape reader continues as Brian A Harron describes an Inexpensive, Optical Paper-Tape Reader. Page 118 James Albus considers the mechanisms of choice in his closing article about A Model of the Brain for Robot Control. Page 130 A Handy Pulser can prove to be very useful when testing a digital cir- cuit. Bob Chrisp shares with us his version of a useful pulse generator. Page 160 In The AMSAT- GOLEM-80, Joe Kasser shows how your com- puter club (or any other group of experimenters) can economically build an S-100 microcomputer. The system is modular and expandable. Page 182 Performing simple con- trol functions with your computer can be easy. Ken Barbier describes how to Add Some Con- trol to Your Computer. Page 196 Publishers Virginia Londoner Gordon R Williamson Associate Publisher John E Hayes Assistant Jill E Calllhan Editorial Director Carl T Helmers Jr Executive Editor Christopher P Morgan Editor In Chief Raymond G A Cote Senior Editor Blaise W Llffick Editor Richard S Shuford Assistant Editors Kent Richard Bob Braisled Editorial Assistants Gale Britton Faith Ferry New Products Editor Clubs, Newsletters Laura A Hanson Drafting Jon Swanson Production Director Nancy Estle Production Editors David William Hayward Ann Graves Faith Hanson Warren Williamson Robin M Moss Anthony J Lockwood Art Director Ellen Bingham Production Art Wai Chiu LI Christine Dixon Holly Carmen LaBosslere Deborah Porter Typographers Cheryl A Hurd Debe L Wheeler Sherry McCarthy Kathy Becker Photostat Technician Tully Londner Advertising Director Patricia E Burgess Assistants Ruth M Walsh Marion Gagnon Janet Ames Eileen Kindl Adv/Prod Coordinator Thomas Harvey Advertising Billing Noreen Bardsley Don Bardsley Circulation Manager Gregory Spltzfaden Assistants Pamela R Heaslip Agnes E Perry Melanle Bertoni Barbara Ellis Dealer Sales Ginnie F Boudrieau Anne M Baldwin Receptionist Jacqueline Earnshaw National Advertising Sales Representatives: Hajar Associates Inc East 280 Hillside Av Needham Heights MA 02194 (617) 444-3946 521 Fifth Av New York NY 10017 (212) 682-5844 Midwest 664 N Michigan Av Suite 1010 Chicago IL 60611 (312)337-8008 West, Southwest 1000 Elwell Ct Suite 227 Palo Alto CA 94303 (415) 964-0706/(714) 540-3554 Traffic Department Mark Sandagata Thomas Yanni Comptroller Kevin Maguire Assistant Mary E Fluhr Officers of McGraw-Hill Publications Company: Gordon L. Jones, President; Group Vice Presidents: Daniel A. McMillan, James E. Boddorf; Senior Vice Presidents: Russell F. Anderson; Ralph R. Schulz, Editorial; Vice Presidents: James E. Hackett, Controller; Thomas H. King, Manufacturing; Robert L. Leyburn, Circulation; John W. Patten, Sales; Edward E. Schlrmer, International. Officers of the Corporation: Harold W. McGraw Jr., President, Chief Executive Officer and Chairman of the Board; Robert F. Landes, Senior Vice President and Secretary; Ralph J. Webb, Treasurer. September 1979 © BYTE Publications Inc ***** I've seen Lanier, Vydec, Xerox, Olivetti, and Wang. I've chosen WORDSMITH from MICRO DIVERSIONS. Congressman Charlie Rose Chairman, Policy Group on Information and Computers LOORDsrrjftb TEXT EDITOR Yes, I'd like to learn more about Wordsmith.™ Send me your information packet. Name. Company Address. City State Zip Micro Diversions, Inc. 8455-D Tyco Road, Vienna, Virginia 22180 (703) 827-0888 BYTE September 1979 5 Look for in personal computer systems made by these companies. Editorial Altos Computer Systems 2378-B Walsh Avenue Santa Clara. CA 95050 Apple Computer 10260 Bandley Dr. Cupertino, CA 95014 Digital Microsystems Inc. (Formerly Digital Systems) 4448 Piedmont Ave. Oakland, CA 94611 Imsai Mfg. Corporation 14860 Wicks Blvd. San Leandro, CA 94577 Industrial Micro Systems 633 West Katella, Suite L Orange, CA 92667 North Star Computer 2547 9th Street Berkeley. CA 94710 Percom Data 318 Barnes Garland, TX 75042 Polymorphic Systems 460 Ward Dr. Santa Barbara, CA 93111 Problem Solver Systems 20834 Lassen Street Chatsworth, CA 91311 Processor Applications Limited 2801 E. Valley View Avenue WestCovina, CA91792 SD Sales 3401 W. Kingsley Garland, TX 75040 Smoke Signal Broadcasting 6304 Yucca Hollywood, CA 90028 Technico Inc. 9130 Red Branch Road Columbia, MD 21045 Texas Electronic Instruments 5636 Etheridge Houston, TX 77087 Thinker Toys 1201 10th Street Berkeley, CA 94710 Vista Computer Company 2807 Oregon Court Torrance, CA 90503 Shugart 6 September 1979 © BYTE Publications lnc The Rationale of Yet Another Homebrew System by Carl Helmers In this issue of BYTE, we are placing a special emphasis on the homebrewing of computers: the craft of assembling the hardware and software of a system from standard components in nonstandard ways. This month's editorial pro- vides a continuation of notes begun in July on the design and assembly of my new homebrew 6809 system. In this editorial, we complete the final details of the physical layout and power supplies of the system, as well as the overall design of the system. We shall also begin a discussion of the actual processor card. Future installments in this series on homebrew, general purpose, com- puter hardware will record details of the system beyond this article's goal of defining a backplane bus structure. As noted earlier ("Editorial," June 1979 BYTE, page 6), the intent of this exercise is to develop a specialized controller node for a loosely coupled system of processors involved with musical applications. The multiple processors ini- tially contemplated were a Pascal-oriented, large personal computer and an ALF products model AD-8 music synthesizer with its 6502 used for house- keeping. In addition to this coordinating task, the 6809 would provide a cen- tral point for the connection of keyboards, displays and other hardware re- quired by musical applications. But ideas change and evolve. Since the 1st installments were written, plans have become slightly more grandiose with my recent acquisition of a New England Digital "Synclavier" music synthesizer and its associated Able/60 minicomputer. Located in Norwich VT, New England Digital is a combined spin-off of the music and electrical engineering departments of Dartmouth College across the Connecticut river in NH. The computer for the music syn- thesizer employs the XPL language as its high-level user interaction. The New England Digital version of XPL is augmented by a floating-point data type. With the exception of an adaptation of UCSD Pascal, which is expected to be available soon, all systems software is written in XPL, including what is described as a 3-pass optimizing XPL compiler. [XPL is the language described in the book A Compiler Generator, by McKeeman, Wortman, et al, published circa 1968. The commonly used microcomputer language PL/M, 1st designed and implemented by Gary Kildall, is very similar to XPL in syntax and semantics. XPL is a simple subset of PL/I, with data types restricted to character and integer forms.] At this point, I now have a need for multiple processor communications beyond the level of 1 large machine (a Western Digital P-engine) driving a smart peripheral through a serial communications link. The smart peripheral will still handle specialized details like the parallel interface to the older syn- thesizer and the eventual interface to an electronically controlled player piano. See photo notes on pages 8 and 9, text continued on page 202 My Shugart followed me li * u \ « IX i "After working all day with the computer at work, it's a kick to get down to Basic at home. And one thing that makes it more fun is my Shugart minifloppy™- We use Shugart drives at work, so when I Pought my own system I made sure it had a minifloppy drive, "Why? Shugart invented the minifloppy. The guys who designed our system at work tell me that Shugart is the leader in floppy design and has more drives in use than any other manufacturer. If Shugart drives are reliable enough for hard-working business computers, they've got to be a good value for my home system. "When I'm working on my programs late at night, I can't wait for cassette storage. My minifloppy gives me fast random access and data transfer. The little minidiskettes store plenty of data and file easily too. "I made the right decision when I bought a system with the minifloppy. When you lay out your own hard-earned cash, you want reliability and performance. Do what I did. Get a system with the minifloppy." If it isn't Shugart, it isn't minifloppy. *A Shugart 435 Oakmead Parkway. Sunnyvale, California 94086 See opposite page for list of manufacturers featuring Shugart's minifloppy in their systems. TM minifloppy is a registered trademark ot Shugart Associates BYTE September 1979 Hardware Basis... These photographs depict some fur details of the physical hardware of the new homebrew 6809 computer system. As noted earlier, Vector Electronic Co com- ponents were used for the assembly of a backplane. Photographs 1 through 5 show various aspects of the new design's packaging. Photo 1: The new computer system's final physical mounting basis is a mahogony box with guide blocks for the backplane assembly. Power supplies are located underneath the box. Power for the com- puter and accessories will be controlled by the standard, household wall switch mounted on the side of the box. Power connections to the backplane power buses will pass through a hole underneath the backplane in this photo. The hole pro- vides an exit path for the flow of hot air from the power supplies. Individual boards of the system plug into the backplane from the top as shown here. The backplane assembly slides into the grooves of the 2 guide blocks. These blocks are bolted to the top of the box using Vi-20 machine-screws and threaded inserts. The grooves for the backplane board were cut l/16th of an inch wide with a router and edge guide. The wood- shop tools required to fabricate this case included a table saw, electric hand drill, drill press, router, belt sander, sabre saw, and the usual collection of hand tools. Photo 2: The power supply modules are attached to 2 wooden brackets which are screwed into the main box by means of Vi-20 machine-screw threaded inserts. The power supply modules are mounted on the brackets using §8-32 threaded in- serts. Ordinary brass finish door stops serve as legs to keep the assembly off the table top, thus allowing natural convec- tion to cool the power supply modules. No attempt is made to calculate heating factors. The inverted cup shape of the box seems like an excellent trap for heat, however, the large hole beneath the backplane assembly at the top of the box provides a relatively low-impedance outlet for the heated air from below. If the temperatures observed under load are excessive, then a fix will be necessary. In a commercial or industrial engineering situation where production of a product is contemplated, this "patch up after pro- blems" strategy is not the recommended practice due to the possibilities of costly errors, but for one of a kind products in a noncommercial and highly experimental context, it is certainly acceptable and can economize on time. Photo 3: (a) Brass machine-screw inserts to provide metal to wood fastening in the (1) (2) (3a) 8 September 1979 © BYTE Publications Inc (5a) (5b) assembly of the computer housing. These particular parts were purchased from the Brookstone Co Peterborough NH. (b) When inserting the machine-screw fasteners into hardwood, better results were obtained when the hole drilled in the wood was l/64th of an inch larger than the recommended size in the instructions. A short section of the machine-screw to be used, together with a hex nut, provide a tool for driving the insert as shown in this picture. When using the §8-32 inserts in hardwood, a slightly larger hole than sug- gested in the instructions is a necessity. Unless the extra clearance is given, the torque on the §8-32 bolt used in driving the insert will cause the insert to twist apart after 1 or 2 uses. Photo 4: The backplane is the first and the most tiresome wiring involved with assembly of a small computer. Its defini Hon is provided by the simple instruc- tions: FOR each free socket, pin BY NUMBER OF each socket, CONNECT that pin to the same pin of the next socket in the backplane! The backplane assembly loas described in the notes of the July 1979 BYTE, page 194. This photo shows the finished backplane after all wiring and installation of bypass capacitors has been completed. Photo 5: The wiring of the backplane, as well as the rest of this computer, was done with the Vector Electronic Co's "slit-N- xorap" technique. An electric eraser was used to motorize the connections, with an adapter custom-made on a small lathe. It is recommended that motorized wiring be employed with the "slit-N-wrap" tech- nique. In previous experimental elec- tronics built with this technique, relia- bility problems were encountered with manual termination of the wires to wire- wrap socket posts. Motorized wrapping with this tool provides a uniform and higher force for stripping the insulation off the wire. At (a) is the adapter: a hollow tube made from 2 junk box spacers, a §10-32 bolt with a hole drilled through it, a brass union between the 2 spacers, and a large brass adapter to which a §10-32 nut is soldered. (This latter kludge is what hap- pens when one makes an adapter on a Sunday afternoon and a §10-32 tap is not available!) At (b) the completed adapter is mounted in the Bruning Electric Eraser in a typical use situation. September 1979 © BYTE Publications Inc 9 Gispcis's Circuit Bella* Copyright © 1979 by Steven A Ciarcia. All rights reserved. Joystick Interfaces Steve Ciarcia POB 582 Glastonbury CT 06033 Photo 1: A typical joystick with 4 potentiometers. The thought that often comes to mind when the word joystick is men- tioned to a computer enthusiast is of a spacewar-type game. A photon torpedo is fired from an opponent's starship, and the thruster joystick is deftly moved to reposition the craft out of its path. All of this occurs without having to take your eyes off the screen. Eye/hand coordination is almost "instinctive." With a glance to the upper right of the video screen, the joystick is tilted to the upper-right corner of its 360° range. This moves the spacecraft toward that coor- dinate. Reverse thrust is accomplish- ed by moving the joystick in the op- posite direction, as though you are pulling back on the throttle of a real craft. Such is the general experience with joysticks. However, the poten- tial use of these devices greatly ex- ceeds that of game playing. A joystick, for those people who are unfamiliar with one, is shown in photo 1. It is an electromechanical device with resistance outputs pro- portional to the X,Y displacement of a central ball and lever. Photo 2 illustrates the mechanical connections to the potentiometers. When the stick is positioned in the center of its axes, the X and Y poten- tiometers show resistances in the center of their ranges. When the stick is tilted to the upper right, both potentiometers are at their full- resistance limit, while the opposite Photo 2: Note how moving the stick moves the gimbal arrangement, which in turn changes the settings of the poten- tiometers. (lowest resistance) is true when in the lower-left position. The outputs of the 2 potentiometers accurately track, as if on an X,Y coordinate axis, the position of the joystick. It should be noted that while it takes only 2 poten- tiometers to define 2-dimensional travel, most joysticks are manufac- tured with 4 potentiometers. This is a remnant of the days when joysticks were connected directly to the 4 deflection-plates of a cathode ray tube (video screen). It is one thing to consider inter- facing a joystick to a computer, and quite another to do it. A joystick is a mechanical X,Y positioning device. Even with proportional output resis- tances, an input interface must be designed to convert position from an analog to a digital representation which can be used by the computer. A further consideration is the resolu- tion, or percent, of full-scale travel per bit sensitivity. Is the application so gross that center and full-scale are the only points of interest, as in a 10 September 1979 © BYTE Publications Inc ILL TO' j - i F |] ~ ' ........mhiii' 'VLiJJ' im'iilllltllllllUH" ' iillMllflU IHIDVIH SYSTEM INCLUDES: 2 Siemens 8" Disk Drives 1 Cabinet with Fan and Power Supply. 1 Tarbell Floppy Disk Inter- face, assembled & tested. 1 CP/M Disk Operating Sys- tem. 1 Tarbell BASIC. All Cables and Connectors. > Complete User Documenta- tion. > Fully factory assembled and tested. 1 ; $1888.00 950 DOVLEN PLACE • SUITE B • CARSON, CALIFORNIA 90746 (213) 538-4251 • (21 3) 538-2254 Circle 360 on inquiry card. BYTE September 1979 11 2 JOYSTICK POTENTIOMETERS J 1 !~7 ^IN4728 ^, F / T 3.9V ^ / rh m „ 1/ iok 470 nsv i C>B3 0> B2 Obi O B0 TO 4 LEAST SIGNIFICANT BITS OF INPUT PORT I ICI LM339 IOM ■VW- Number Type IC1 LM339 IC2 LM339 O 87 OB6 OB5 C>B4 TO 4 MOST SIGNIFICANT BITS OF INPUT PORT I + 5 V GND 3 12 3 12 "R«= APPROXIMATELY IOOOHMS Figure 1: Low-resolution static interface. This interface is for 1 2-potentiometer joystick. For 4-potentiometer joysticks, build a second circuit like this one, and interface it to another input port. Note that if the comparator does not trigger at full-scale setting, a small resistor may have to be added at Rx (marked with asterisk). game control, or is the application one which requires fine control, such as a cursor-positioning device in a high-resolution graphics system? All joystick interfaces are not created equal. There is a trade-off between hardware and software. The lower the resolution, the fewer the parts. The higher the resolution, the greater the electrical complexity or the software interaction with the in- terface. It is also important to recognize that computer systems which operate only in a high-level language like BASIC cannot use an interface design that requires an assembly language subroutine as an integral component. In such instances only a static interface can be used. Included in this presentation are 4 interface designs which should cover most requirements, as well as demonstrate the considerable dif- ferences between them. The 4 types are: • low-resolution static • high-resolution fully static hardware • software-driven pulse-width modulated • high-resolution analog-to-digital Low-Resolution Static Interface First of all, static simply means that the interface hardware determines the potentiometer position value and pre- sents it in constant, parallel digital form to the computer. When the interface is attached to any parallel input port, this joystick value can be read with a single INPUT command in BASIC. As far as the computer is concerned, the value is fully static, and the computer reads whatever data is there when the INPUT is ex- ecuted. The interface hardware has the responsibility of asynchronously updating the digital value as the stick is moved. Often the joystick is simply used to indicate relative direction and magnitude. In a wheelchair, for in- stance, full linear control of speed and direction would require rather expensive drive electronics. Most chairs use simple relay contacts and provide 2 or 3 selectable speeds. A joystick control built for this applica- tion would not have to have a resolu- tion of 8 bits, but could, in fact, suf- fice with 2. Figure 1 shows a low- resolution static output joystick inter- face suitable for use in this application. Each potentiometer is connected as a voltage divider between a reference voltage source of 3.9 V and ground. The voltage output of each poten- tiometer is, in turn, fed to a 2-bit, parallel analog-to-digital converter. This type of converter uses 4 com- parators set for 25%, 50%, 75%, and 100% of full scale. If a voltage, when applied, is less than 0.975 V, all com- parator outputs will be at V. At 1.0 V, corresponding to the joystick be- ing moved 25% of full scale, the least significant bit (LSB) of the converter will be a logic 1, while the other bits are low. Similarly, at full input all 12 September 1979 © BYTE Publications Inc theirs, ours, So you didn't think documentation made a difference. Sure, MicroSource is flexible, powerful, versatile. Sure, it's sophisticated yet simple: the first user-oriented software. But you may not be aware of the biggest difference of all. Documentation. The most extensive in the industry. Support makes a difference, too. The support of some of the world's leading microcomputer people. The support of stringent field testing and follow up. The invaluable support of business software experts dedicated to helping you manage information in real-world environments. Not just when you acquire software, but as you implement, as you train, as you use Microsource to solve your contemporary business problems. The MicroSource Difference means dealer support, too: we back every dealer with our experience, our knowledge, our integrity. Plus, the materials and resources he needs to provide the finest in software solutions and data base management. From AutoScribe™, the versatile word processing package that means business ... to Bookkeeper™, designed by a CPA to produce efficient client writeups. From the powerful LedgerPlus™ financial package to MoneyBelt™, the flexible accounting system, both for small to medium sized businesses ... or small to medium sized departments of big corporations. TimeKeeper™ — for the professional practice or the corporate service department — bills for time, when time means money. All MicroSource is backed by exhaustive operations manuals, incomparable factory support, and system expandability. It runs on North Star, Vector Graphics, Heath Data Systems, Apple and TRS-80 . . . before long, CP/M, Cromemco, Data General and MicroNOVA. Sample the MicroSource difference. snivel v^ov^ui w Ask your dealer about powerful, user-oriented MicroSource software. Or call the telephone number below for the nearest MicroSource dealer near you. 1425 W. 12th PI. ■ Tempe. AZ 85281 • 602-894-9247 Circle 222 on inquiry card. BYTE September 1979 13 comparators will be triggered, and bits thru 3 will be logical Is. Additional encoding logic can be added to produce a true 2-bit representation from the 4 compara- tors, but it is just as easy for a com- puter to interpret it directly. With a 4-bit connection as shown, used in a BASIC program, 25% of full scale would be 1 decimal, 50% of full scale would be 3 decimal, 75% of full scale would be 7 decimal, and full scale would be 15 decimal. It should be easy to trigger any action by a coin- cidence with these values. The real significance of this method is that the potentiometer position is presented statically to the computer and re- quires no other interaction. This makes it ideal for direct use with BASIC. 5V A 1 50K ;o.i/iF 3 4 ■ + 5V A V R 2 __ 4 50K ^pO.I M F - POSITION 30 Bl B2 B3 B4 B5 B6 B7 IC6 7404 E* 8 u. I3 47ft 7400 1 I 10 i ^ 13. . \ g LOAD "TTJJ IC3b)o^ f-^l _J/ > ~ O.I/iF 7400 13 II Q A Qb Qc Od LOCK 2 £| g A B C D II CLEAR CLOCK 0>- 6 COUNT IC6 7404 12 13 12 II 10 Qa Ob Qc Qd lock 2 !£« B A B C D A B C D INPUT B ICI I INPUTA ? 493 ROU) RO(2) L^i A B C D INPUT B I C 12 INPUTA ? 493 RO(l) R0(2) 14 September 1979 © BYTE Publications Inc High-Resolution Static Interface It is quite possible that 2 bits of resolution is not enough for your application, but direct compatibility with a slow, high-level language is still a requirement. Expanding the parallel comparator method will work in theory, but you must realize that a 4-bit analog-to-digital con- verter uses 15 comparators, and an 8-bit, parallel analog-to-digital con- verter needs 255 comparators! So much for that method. Realizing that the output of the joystick is a variable resistance, we can use this to advantage. This resis- tance can set the time constant of a Number Type + 5 V GND IC1 74121 14 7 IC2 74121 14 7 IC3 7486 14 7 IC4 7400 14 7 IC5 7400 14 7 IC6 7404 14 7 IC7 7493 5 10 ice 7493 5 10 IC9 7495 14 7 IC10 7495 14 7 IC11 7493 5 10 IC12 7493 5 10 IC13 7495 14 7 IC14 7495 14 7 IC15 NE555 8 1 5V A y FREQUENCY *? ADJUSTMENT IOK ICI5 NE555 RESET VCC DISCHARGE OUTPUT THRESHOLD TRIGGER GROUND BYPASS iO.ljiF rh O.OI/iF 9h- J Figure 2: High-resolution, static interface. Each potentiometer in the joystick con- trols the pulse width of a one-shot. The pulse width can vary from 35 ms at full- scale to 100 /as at 0. If a joystick with 4 potentiometers is used, a duplicate circuit may be constructed for the 3rd and 4th potentiometers. function which has a pulse width pro- portional to joystick position. Figure 2 illustrates an interface design which uses this technique. The 2 joystick potentiometers Rl and R2 control the pulse width of a one-shot (monostable multivi- brator). The one-shot has a pulse width of 35 ms when the poten- tiometer is at 50 k ohm full scale and something less than 100 lis at 0% of full scale. A 7.5 kHz clock signal asynchronously triggers the one-shots. When the one-shot fires, its duration is proportional to the joystick posi- tion and will vary from approxi- mately to 35 ms. Using midscale pulse width of 17 ms as an example, the circuit timing is as in figure 3. On the leading edge of the one-shot signal, a clear pulse is generated through an edge detector configured 7486 device. The clear pulse resets the 2 7493s which form an 8-bit counter. Once cleared, the counters start counting clock pulses for the duration of the one-shot's period. On its trail- ing edge, a load pulse is generated which loads this 8-bit count into an 8-bit storage register. The computer is connected to read this 8-bit value through a parallel input port. Suc- cessive clearing and counting opera- tions update the register every 35 ms or so (worst case). The clock rate is 7.5 kHz which has a period of 133 /xs. If the one-she has a pulse width of 17 ms, then 127 clock pulses would be CLOCK ONE SHOT Q jil. gated to the counter. Of a total possi- ble 255 counts, 127 would represent 50% of full scale. Software-Driven Interfaces So far I have discussed only static interfaces. If the computer used with the joystick has sufficient speed and excess computing time available, then it is reasonable to use the computer to directly determine the one-shot period. Figure 4 shows a circuit which directly connects to the computer bus and demonstrates this technique. The circuit as shown is wired for I/O (in- put/output) port decimal 255 or hexadecimal FF. The 4 joystick poten- tiometers are used as the timing resistors on 4 NE555-type one-shots. When an OUT 0, FF is executed in assembly language, it triggers all 4 one-shots. To keep track of the pulse widths, a 74125 3-state driver gates the one-shot outputs onto the data bus during an IN FF instruction. By looping through this program a number of times and keeping track of the logic levels of the 4 one-shots, the computer can accurately determine joystick position in terms of loop counts of instruction times. Listing 1 is a program which does this for 1 potentiometer. High-Resolution Analog-to-Digital While all methods are in some way analog-to-digital converters, the last 7.5 KHz CLEAR LOAD COUNT TO 35 mSEC 20/iSEC 20 M SEC TO 255 PULSES Figure 3: Timing diagram for interface of figure 2. The driving clock signal is 7.5 kHz. The one-shot can be triggered for periods of to 35 ms, depending upon the position of the joystick. When a reading is to be taken, the counters are cleared. Counts are made until the one-shot signal drops, and then a load signal is sent to the interface. At this point the counter is read to determine the position of the joystick. September 1979 © BYTE Publications Inc 15 MVI B clear B OUT FF,0 trigger one-shots AGAIN INR B increment B register IN FF read potentiometers ANA 01 isolate bit JNZ AGAIN continue as long as one-shot is high HLT value is in B register Listing 1: A typical assembly language program for using the joystick interface of figure 4. After the one-shots are triggered, the program loops and checks the status of bit 0. When this bit is set, the conversion value is in register B. This program assumes that there is only 1 value being checked, and it is being input through bit 0. method is in fact an 8-bit absolute- analog-to-digital converter, typical of the type used in computerized meas- urement applications. ICl is an 8-bit Number Type + 5 V GND IC1 NE556 14 7 IC2 NE556 14 7 IC3 7430 14 7 IC4 7400 14 7 IC5 74125 14 7 digital-to-analog converter that pro- duces an output voltage proportional to a digital input applied to pins 5 thru 12. For a complete explanation of this device, I refer you to a pre- vious " Ciarcia's Circuit Cellar" arti- cle, "Control the World" (September 1977 BYTE, page 30). This article also outlines calibration and test pro- cedures. The 3 basic sections are a computer-controlled voltage source (ICs 1 and 2), an analog-input multiplexer (IC3) which selects an in- dividual joystick potentiometer by a 2-bit address code, and a comparator (IC4) which compares these voltages. In operation, the digital-to-analog converter is first set to V out (hexa- decimal 00 digital input to it) and 1 potentiometer is selected through the multiplexer. If V0 from the digital-to- analog converter is less than V in from the potentiometer, the output will be logic 0. Next, the digital-to-analog converter input setting is incre- mented, and the comparator output is checked again. Eventually an input count will be reached which will exceed V,„. The comparator output will then be a logic 1. The digital-to-analog con- verter input count is now the value of the voltage V,„. The worst case re- quires 256 iterations using this R| THRU R 4 ARE JOYSTICK POTENTIOMETERS + 5V ao rz> TO COMPUTER j CONTROL BUS I/O r^. WRITE I '^E> READ I — >^ IC4 7400 I ■ 50K >2.2K 2 Ida OUTPUT THRESHOLD DISCHARGE CONTROL TRIGGER 5 ICl NE556 2 3 1 ^O.I^F 7 /TN 0.01/iF n 1* HZ> D o I* R 2 -> 50K OUTPUT THRESHOLD DISCHARGE CONTROL TRIGGER "1 0.01/tF FR3 SOK O.ljiF OUTPUT THRESHOLD DISCHARGE CONTROL TRIGGER ICE NE556 ^-pO.OI^F k R 4 /S 50K OUTPUT THRESHOLD DISCHARGE CONTROL TRIGGER ~zy* O.OI/iF HZ>°I TO COMPUTER DATA BUS ■£>»! -O D 3 Figure 4: Software-driven interface. If the computer can directly read the input from the joystick interface, the hardware required can be greatly simplified. When hexadecimal FF is output to port 0, all 4 one-shots are triggered. The pulse width is then determined by a program running through a short loop looking at the logic levels of the 4 one-shots. Listing 1 shows a typical program for this application. 16 September 1979 ft) BYTE Publications Inc no loose ends All-ln-One: computer, floppy, I/Q16K RAM. $1595* CNI Tn M itcroprocmort tlMtl 2.WXHI I 1(1 byttl !Mt «p.nd«b]l to 4BK Itipliyi 23 lintf by U chirietorl Chtrictirsl 5 x ? dot utrix, uppor I lottfr cut iripnleil 33 spicul jrophlci chiricUn Ityboirdi 72 h»yt, £1 olphonuoirie I 12 function control (8 uur-dtfiniblo) luwic ktWIl" » »•»' taw Iddriiilnji rtUtlv* t dirict for fall ciirior control (fit f»«etlo«i Intirt or dtloti chtrKtor or lint •idoci Koriil and rtvorit by chirictir for Klojhl Ifhtlnf . New Heathkif H89 All-ln-One Computer Heath takes the risk out of selecting a balanced computer system. Now, video terminal, floppy, keyboard and 8-bit computer are brought together in one self-contained, compact unit. Nothing hangs out. Two Z80's The personal computer has never been simpler. Or smarter. Two Z80 microproc- essors mean terminal never shares pow- er with computer, as do most desk-top units. So this terminal is capable of a multitude of high-speed functions, all controllable by keyboard or software. •$1195 without floppy. Mail order kit price, F.O.B. without notice. 102K bytes storage Built-in floppy disk system gives you fast access to programs and data. Each 5 1 A- inch diskette has more than 102K bytes of storage area, enough to hold entire files. The All-ln-One comes with 16K RAM, expandable to 48K. Hundreds of uses at home or work The All-ln-One Computer runs programs written in MICROSOFT'" BASIC and ASSEMBLER Languages. And it accepts all current software written for the popular Heathkit H8 computer. You can choose from scores of practical programs for home and business. Learn by building What better way to learn about comput- ers than to build one yourself? The All- ln-One is available in easy-to-build kit form, as well as completely assembled. Like all Heath electronic kits, it comes to you with its own easy-to-follow assem- bly manual and a nationwide network of service centers to assure smooth sailing. FREE CATALOG For complete details on the Heathkit H89 All-ln-One Computer and nearly 400 other electronic kits for your home, work or pleasure, send today for the latest Heathkit Catalog of values. Benton Harbor, Ml. Also available at Heathkit Electronic Centers at slightly higher prices. Prices subject to change CP-165 Heathkit HEATH COMPANY, DEPT. 334-570, BENTON HARBOR, Ml 49022 Circle 216 on inquiry card. BYTE September 1979 17 Number Type +5 VGND + 15 V + 15 V IC1 MC1408-L8 13 2 3 IC2 LM301A 4 7 IC3 CD4051 4 8 IC4 LM301A 4 7 DIGITAL-TO-ANALOG CONVERTER + I5V FROM COMPUTER OUTPUT PORT I B 7 O B 6 O- B5 O" b 4 o- B 3 O" B 2 O- B| O- B O MSB 5 10 LSB 12 ICI MCI408LS lo -Vref RANGE CONTROL COMPEN i 33pF -I5V FROM COMPUTER OUTPUT PORT 2 B| O" B O- 10 IC3 CD405I OUT INI IN2 IN3 IN4 INH C W* I.8K FULL SCALE ADJUST 2K — y& — ? ?IN823A 6 " OFFSET ADJUST 5K — y& — 2.2K -WA<- I^F /77 2.7K _VW— l M F rn 47pF 4.7K — W\/- :i50pF LM30IA ; 3.3K DIGITAL TO ANALOG CONVERTER SET FOR TO 2.56V JOYSTICK MULTIPLEX V REF = 2.56V FIRST PAIR OF POTENTIOMETERS ! SECOND PAIR OF POTENTIOMETERS R 4 IOOK Figure 5: High-resolution analog-to-digital conversion. This hardware-oriented device multiplexes 4 voltage inputs (from the joystick potentiometers) and has the capability of handling 4 more voltages. method. A better technique is suc- cessive approximation where the computer progresses through a binary search to "zero in" on the final value. A full explanation of suc- cessive approximation is delineated in my article entitled "Talk to Me: Add a Voice to Your Computer for $35" (June 1978 BYTE, page 142). With the digital-to-analog con- verter set for a full-scale value of 2.56 V, each count is equivalent to 10 mV. Only 4 channels of the CD4051 are used for the joysticks, leaving another 4 channels as auxiliary inputs from external sources. Thus it is possible for this interface to serve a dual role because of its high accuracy COMPARATOR -O VqUT . 33pF TO COMPUTER INPUT PORT 1 C>Bo LM30IA and resolution relative to the other methods. You should now realize that both the design and construction of a joystick interface are influenced by many factors. It is not unusual to find one manufacturer charging $50 for a joystick, while another charges $200. Resolution, accuracy, and software interaction are the prime considera- tions. Where static inputs are re- quired, the hardware will necessarily be more complicated. Resolution and accuracy ultimately determine the complexity of the interface. For simple spacewar-type games, the circuit of figure 1 should suffice. For more demanding applications such as cursor control in a high- resolution graphics system, figure 5 may be the optimum choice. Be careful when buying joystick inter- faces. Make sure that they mate with your program requirements and your system's abilities. Next month's "Circuit Cellar" feature will discuss a stand-alone, light-emitting diode display board. ■ 18 September 1979 © BYTE Publications Inc "Our inventory is our existence* Think we'd trust it to anything less than Scotch Brand Diskettes?" Don Stone, President, Mass. Auto Supply Company, Inc., Boston, Mass. Scotch Diskettes are the diskettes you can depend upon with the information your business depends upon. Each one is tested and certified error-free before it leaves our factory. Because we know nothing less than perfection is acceptable for your vital business data. Scotch Diskettes are available in regular or mini sizes, compatible with almost any system. To find out where you can purchase Scotch Diskettes, call toll free: 800-328-1300. (In Minnesota, call collect: 612- 736-9625.) Ask for the Data Recording Products Division. In Canada, write 3M Canada Inc., London, Ontario, N6A 4T1. If it's worth remembering, it's worth Scotch Data Recording Products. Circle 368 on inquiry card. BYTE September 1979 19 Introduction to Multiprogramming Mark Dahmke 8312 Selleck 600 N 15th St Lincoln NE 68508 Multiprogramming has usually been considered out of reach of the average personal computer experi- menter using a small or medium scale computer. Actually, anyone with a processor above the level of an 8008 can operate a multiprogram or multiuser system. The original pur- pose of multiprogramming was to allow more than 1 user to take advan- tage of a computer simultaneously. This increased the productivity of the machine by allowing programs to run while other programs were awaiting user input, access to a disk, etc. This may seem to conflict with the advantages inherent in micro- processor based systems (single user systems and low cost). However, there are many instances where the ability to run more than 1 program at a time may be advantageous. Note that the statement "more than 1 pro- gram may run at a time" does not mean simultaneous execution. That is the definition of multiprocessing (more than 1 processor on the bus), not multiprogramming. To describe multiprogramming more effectively, I shall refer to a more well-known function in com- puters: real-time interrupts. Suppose we are using a microcomputer to manage the environment in a small office building. Normally we want to continually poll (scan) the sensors that are distributed throughout the building and adjust heating, cooling and lights on the basis of temperature and time of day. Let us say that during normal operation, someone in the building wants to change the temperature of an office. One way to do this is to have a video terminal and keyboard attach- ed to the system that generates an in- terrupt when a keyboard request is made. Upon receiving the interrupt, the computer saves the status of the current program and enters or trans- fers control to the keyboard read routine. As soon as the user has made the desired change, the system loads the old status information and returns to the original program. This same in- terrupt technique could be used to design a time shared system that would allow several terminals to be hooked up to a processor. Each ter- minal would generate an interrupt, and whichever program was active would be put in a wait state. This arrangement only works well for a few terminals, though. You can ima- gine what would happen if everyone happened to press a key at the same time. Figure 1 shows timing comparisons of several modes of operation already discussed. In figure la 2 independent processors are shown, each doing something different and neither in- terfering with the other. This is known as multiprocessing. The pro- cessors may or may not be sharing I/0(input/output) terminals or memory. In figure lb 2 processors are shown in a master-slave arrangement. Perhaps the slave processor performs floating point arithmetic or some complex I/O function. The master processor can give the slave processor commands via an interrupt and con- tinue other processing until the slave informs it that it has finished the desired operation. Figure lc shows a single processor with an interrupt being applied. The processor temporarily gives control to the routine specified by the inter- rupt hardware and begins executing it. When complete, it returns control to the main program. Figure Id shows the multiterminal timeshare system. Usually the interrupt hardware con- tains provisions for daisy chaining or prioritizing the interrupts as they come in. Thus, if terminal 6 applies an interrupt and the processor is busy with terminal 7, terminal 6 is not allowed to interrupt the processor until terminal 7 is finished. Using multiprogramming is like using real-time interrupts. A multi- programmed system uses interrupts, but in a more efficient way. Imagine a simple 2 program situation. Suppose program A is running and no other About the Author Mark Dahmke is currently employed by the University of Nebraska Computer Network as a programmer/analyst in the Academic Com- puting Services section. He is also a senior computer science major. At home, Morlc owns an 8080 based system with 32 K bytes of memory and dual iCOM floppy disk drives. His work involves graphics, electronics, writing, systems programming and speech syn- thesis. 20 September 1979 © BYTE Publications Inc ALTOS presents a new standard in quality and reliability mm m a WERE ALTOS COMPUTER SYSTEMS. Our SUN-SERIES ACS8000 business/scientific computer creates a new standard in quality and reliability in high technology computers. HIGH TECHNOLOGY The ACS8000 is a single board, Z80®* disk-based computer. It utilizes the ultra-reliable Shugart family of 8 inch, IBM compatible, disk drives. A choice of drives is available: single or double density, single or double sided. Select the disk capacity you need, when you need it: V4M, 1M, 2M, or 4M bytes. The ACS8000 features the ultimate in high technology hardware: a fast 4 MHz Z80 CPU, 64 kilobytes of 16K dynamic RAM, 1 kilobyte of 2708 EPROM, an AMD 9511 floating point processor, a Western Digital floppy disk controller, a Z80 direct memory access, Z80 Parallel and Serial I/O (two serial RS232 ports, 1 parallel port), and a Z80 CTC Programmable Counter/Timer (real time clock). In essence, the best in integrated circuit technology. ALTO* COMPUTER SYSTEMS BUILT-IN RELIABILITY The ACS8000 is a true single board computer. This makes it inherently reliable and main- tainable. The board and the two Shugart drives are easily ac- cessible and can be removed in less than five minutes. All elec- tronics are socketed for quick replacement. Altos provides complete diagnostic utility software for drives and memory. QUALITY SOFTWARE Unlimited versatility. The ACS 8000 supports the widely accepted CP/M®** disk operating system and FOUR high level languages: BASIC, COBOL, PASCAL and FORTRAN IV. All available NOW. PRICE ACS 8000-1, single density, single-sided ['A Mb] $3,840 ACS 8000-2, double density, single-sided [1 Mb] $4,500 ACS 8000-3, single density, double-sided [1 Mb] $4,800 ACS 8000-4, double density, double-sided [2 Mb] $5,300 Brackets show disk capacity per standard two drive system. All models come standard with 32 Kb RAM and two 8" disk drives as shown above. Expansion to 64 Kb is $363 per 16 Kb. FPP, DMA, software optional. Dealer/OEM discounts available. Delivery: 30 days ARO, all models. •Z80 is a trademark of Zilog. Inc. Circle 6 on W U "V card - •*CP/M is a trademark of Digital Research, Inc. 2338A WALSH AVENUE • SANTA CLARA • CA 95050 • (408) 244-5766 programs have been started. Then a user initiates (loads) another program called B. How will program B gain control of the system so that it might start to execute? The process of passing control from one program to the next is usually handled by an operating system module referred to as an inter- rupt call routine. Normally, to save the programmer the trouble of making sure that this routine gets called at regular intervals, the routine is usually imbedded in many of the I/O driver routines or other standard utility subroutines on a system. Note that this technique will in no way upset any of the flags or registers of the routine it is called from. This interrupt call program will: 1. Determine if any other programs are waiting to execute. 2. If so, save all registers and flags on the stack and save the address of the current program's stack pointer in a special table in memory. 3. Load the new program's stack pointer from the table, pop all registers and flags off the stack. 4. Return to the new program. Loading the new stack pointer raises some interesting questions. If program B has not yet begun, how could its registers have been pushed onto its stack? Figure 2 shows the stacks of both programs as they would be at each step in the previous- ly described interrupt call routine. Part of the job of the routine that in- itialized program B is to set up a dummy stack and stack pointer such that the program counter address on the top of the stack contains the entry point of program B. Thus, when the interrupt call routine reaches step 4, it will execute a return instruction, then pop the entry point address off the stack and begin executing program B. When the interrupt routine is called again, it will see that program A is waiting and will save all of program B's registers and flags, swap stack pointers and return to program A at the point where it was first inter- rupted. All this activity will take place every time the interrupt routine is called, but if one of the programs gets caught in an infinite loop, the inter- rupt call routine may not get called. The simplest way to avoid this kind of problem is to add some hardware to provide external timed interrupts. As shown in figure 3, the interrupt timer is set to provide an interrupt every 10 ms. A reset line is provided PROCESSOR PROGRAM A PROGRAM A PROGRAM A PROGRAM A PROGRAM A (a) PROCESSOR 2 PROGRAM B 10 PROGRAM B PROGRAM B 10 PROGRAM B PROGRAM B PROGRAM 8 (b) (c) (d) PROGRAM A PROGRAM A CONTINUES OTHER WORK PROGRAM A / SLAVE PROGRAM INITIATED SLAVE 1 SLAVE SENDS READY SIGNAL INACTIVE OR DOING OTHER WORK PROGRAM A SLAVE PROGRAM INACTIVE OR DOING OTHER WORK / / EXTERNAL INTERRUPT / OCCURS PROGRAM A INTERRUPT ROUTINE PROGRAM A RESUMED / OPERATING TERMINAL SYSTEM SERVICED OPERATING SYSTEM TERMINAL 7 SERVICED TERMINAL 6 SERVICED TERMINAL 7 COMPLETED TERMINAL 6 COMPLETED OPERATING/ SYSTEM / TIME Figure 1; Timing diagrams for 4 different system organizations. Figure la is a multiprocessing example using 2 independent pro- cessors. Figure lb is a multiprocessing example using 2 processors connected in a master-slave configuration. Figure lc is a single pro- cessor with 1 level of interrupt. Figure Id is a single processor with 8 levels of interrupts. Each of the 8 levels is activated by 1 of 8 ter- minals. 22 September 1979 © BYTE Publications In STACK A STACK POINTER A ' 11 ) PROGRAM COUNTER (HIGH) — PROGRAM COUNTER (LOW) AFTER INTERRUPT CALL STACK B (3) PROGRAM COUNTER (HIGH) PROGRAM COUNTER (LOW) ALL REGISTERS FLAGS STACK POINTER B (STACK POINTER SAVE AREA ) (2) PROGRAM COUNTER (HIGH) PROGRAM COUNTER (LOW) ALL REGISTERS FLAGS STACK POINTER A (STACK POINTER SAVE LOCATION) STACK B (4) STACK POINTER B- PROGRAM COUNTER (HIGH) PROGRAM COUNTER (LOW) Figure 2: Arrangement of all stacks and stack pointers at each interval of an interrupt call routine. in the event that the interrupt routine is manually called (through the soft- ware method). The timer may be reset to give the program its full 10 ms. A disable line is provided to allow the user to turn off the timer for special applications (software timing) in which the processor must not be in- terrupted. Figure 4 shows our previous exam- ple of figure 1, but with the extra hardware generated interrupts added. In figure 4a some software interrupts are mixed in with the hardware inter- rupts. The timer is reset after each call to the interrupt routine. Figure 4b is the same except that the timer is not reset after each call. A Complete System There are limitless ways to go about developing a computer system that will be easy to use. A look at the current market shows this to be true, perhaps even to a greater extent on the small systems level. I will not at- tempt to describe all possible varia- tions available on a multiprogram- ming system, but I will try to give as The following are essential: generalized a view as possible. First, we must consider what is 1. Some form of operating system necessary to make a useful system. that allows simplified user com- 4> £~ 470ft 4 — va — s (THREE STATE) > C^ -[ ~> TO INTERRUPT LINE OF PROCESSOR D FLIP-FLOP o Figure 3: Simple hardware interrupt timer set for 10 ms intervals. September 1979 © BYTE Publications Inc 23 TIMER RESET BY SOFTWARE TIMER RESET BY SOFTWARE TIMER RESET BY SOFTWARE (a) PROGRAM A PROGRAM B PROGRAM A PROGRAM B PROGRAM A PROGRAM B PROGRAM A PROGRAM B TIMER INTERRUPT TIMER INTERRUPT 10 INTERRUPT CALL TIMER NOT RESET TIMER INTERRUPT TIMER INTERRUPT 10 INTERRUPT CALL 10 INTERRUPT CALL TIMER NOT RESET (b) PROGRAM A PROGRAM B PROGRAM A PROGRAM A PROGRAM B PROGRAM B PROGRAM A TIMER INTERRUPT TIMER INTERRUPT 10 INTERRUPT CALL TIMER INTERRUPT TIMER INTERRUPT 10 INTERRUPT CALL TIMER INTERRUPT TIMER INTERRUPT 10 INTERRUPT CALL Figure 4: Interrupt timing example of figure 1 reviewed with the addition of a hardware timer. The timer may be used in 2 ways: The example in figure 4a resets the timer on each interrupt call. This allows each program to receive its full 10 ms time slot. The example in figure 4b does not reset the timer. Therefore, a hardware interrupt occurs every 10 ms. munications (ie: BASIC, DOS, CPM). 2. Convenient mass storage I/O (cassette or disk). 3. Sufficient memory to handle all programs. Another consideration might be the internal architecture of the processor, but that is another level of problem. Figure 5 shows the memory layout of a typical multiprogramming system. To maintain a simple system, I have combined the operating system with the timesharing routines that support all terminals (video displays, keyboards and teletypewriters). This means that each time the operating system gains control (through an interrupt call or timer interrupt), it will complete its own activity and then transfer control to the time- sharing program for the remainder of the time slot. If the operating system is given highest priority, the response times of the terminals should not suf- fer. The operation of the timeshare program can be treated as a multi- BOOTSTRAP LOADER INTERRUPT ROUTINE TIME- SHARING SUPPORT PROGRAM ALL I/O ROUTINES OPERATING SYSTEM (0) STACK USER PROGRAM 1 STACK 1 USER PROGRAM 2 STACK 2 ~~ — ^ Figure 5: System geography of a typical multiprogramming system with space for the operating system and 2 other programs. program system in miniature, where each terminal is given a time slot, or it may be designed to simply scan the terminals, choosing a new terminal each time it is given control. Controlling I/O Many programmers have dis- covered the convenience of vectoring all I/O through 1 subroutine; this simplifies programming greatly and makes system changes much easier. Typically, 1 subroutine will accept an operand (if necessary) and an operator function code passed from the main program and will decide which I/O function to perform. In my hypothetical computer, this ap- proach will be used. Note that in some large computer systems, the I/O driver programs can only be ac- cessed by executing a special kind of interrupt call that informs the operating system that the user's pro- gram desires to perform some kind of input or output operation. The oper- ating system then takes charge, per- forms the I/O for the program in question, and returns pointers telling where the input data was stored in memory or that the requested output function has been completed. This type of I/O handling is neces- sary because the I/O controllers are extremely complex and are capable of performing an entire I/O operation 24 September 1979 © BYTE Publications Inc Circle 9 on inquiry card.- / nh -r&H ^w How to buy -*- 11 personal compute s In California, a store owner charts sales on his Apple Computer. On weekends though, he totes Apple home to help plan family finances with his wife. And for the kids to explore the new world of personal computers. A hobbyist in Michigan starts a local Apple t Computer Club, to challenge other members €Jl *° com P u ^ er ga me s of skill and to ^**^ trade programs. Innovative folks everywhere have discovered that the era of the I personal computer has already begun — with Apple. Educators and students use Apple in the classroom. Businessmen trust Apple with the books. Parents are making Apple the newest family pastime. And kids of all ages are learning how much fun computers can be. Visit your local computer store The excitement starts in your local computer store. It's a friendly place, owned by one of your neighbors. He'll show you exactly what you can use a personal computer for. What to look for Your neighborhood computer store has several different brands to show you. Chances are the salesman will recommend an Apple Computer. Apple's the one you can program yourself. So there's no limit to the things you can do. The more you use your Apple the more uses you'll discover. So it's important that Apple is the computer with more expansion capability. You can't outgrow Apple. It's your move Grab a piece of the future for yourself — we'll give you the address of the Apple dealer nearest you when you call our toll-free number. Then drop by and sink your teeth into an Apple. ^tfSS (800)538-9696. In California, (800) 662-9238. without processor intervention. In fact, it would be very inefficient to make the processor of a large system perform these menial tasks when it could be working on more important programs. In microcomputer systems we are not normally concerned with the optimization of I/O functions and it does not really hurt performance to have the processor perform most of the I/O. Consequently, the I/O driver routines in the system I am describing will not be considered as part of the operating system. They are just utility subroutines that may be called by the user's program. Defining the Necessary Tables With only 2 programs very few, if any tables are needed to tell the inter- rupt routine which program was ac- tive at the instant the system was in- terrupted and which program is next in line. But imagine a system capable of supporting 10 or more programs: some form of priority scheduling will be needed, as well as a table to hold all of the stack pointers of the inactive programs. To handle the list of programs (herein referred to as tasks), we must define a task control table that keeps track of a number of pointers and descriptors. First, each entry will begin with the task number that uni- quely defines each task. Next, we will include the priority of the task on an arbitrary scale of to 10. It will then get the processor before a task of lower priority (10 is highest). If 2 tasks have the same priority, the first one in line in the task control table will get control. The task control table must also keep track of the last value of the stack of each task and whether or not the task may be inter- rupted (in the case of critical timing loops). Another important status byte that must be kept is the current activity indicator. This byte contains the task number of the currently active task. Now let us assume that we have 3 dif- ferent tasks running and all have been initialized (stored in the task control table). The first task has a task number of and a priority of 10. Generally the operating system is 8P2SM PARALLEL/SERIAL I/O BOARD WITH MODEM PARALLEL PORTS: « I'oris. (.4 i,,i.,/ )„-,/»,.< t.oi SERIAL PORTS: -' Serial Ports vviih as\( One Port 1 II i Idll'd Minimi lines oi RS-.M2 r I I i I 1 Please rush the following : AVAILABLE BAUD RATES: One Poii 1 II 107..! kilobaud i r ii(, kilobaud iiii kilobaud in 4 kilobaud V) 2 kilobaud 9600 baud 4800 baud J4(!(i baud oi MODEM. 1760 baud U00 baud 600 baud 100 baud 150 baud lid haud 75 band 27.5 baud □ 1/0 Card (kit) □ I/O Card (assembled) CompviT „ CA residents add 6% (II any user supplied baud rales up lo 50C kilo )aud. MODEM: BUS TYPE: PRICE: F nil Duplex, .inxwef < S-100 % 1-4't .kill tl'l'l (assembled and ii originate. 100 Baud . ° „ esledl #** MicroDaSys P.O. Box 36051 Los Angeles, CA 90036 (213) 935-4555 given the task number designation. Since the operating system and timeshare program (user terminals) are considered one big program in this example, task is also the designation of the timeshare system. Task 1 is a program that one of the users submitted (initiated) from a ter- minal; it has a priority of 10. Task 2 was also loaded and initiated by a user through the timeshare terminals, and it has a priority of 10. Imagine that the timeshare pro- gram calls the I/O driver program to write a character out to a terminal. Since there could be many terminals connected to the system, how does the program know which one to write to? It would be very inefficient to have different routines for each device, but the only way that a pro- gram could tell the I/O driver which specific display to write to is for the calling program to know the physical address of that terminal. Passing the actual address of the device ruins the neatness of the I/O routine, though. It is more convenient to specify the function to be performed (1 = write to video display; 2 = read keyboard; 3 = write to cassette; 4 = read cassette). The solution is to have another en- try in the task control table called a communications control block pointer that points to the location of the communications control block for the particular task. Since each task is given its own block, the user may define his or her own functions and addresses. Thus each program may have its own video display, key- board, cassette interface and disk. The communications control block contains a list of function numbers, the address of the I/O port or memory mapped port, and the ad- dress of the I/O subroutine that will perform the operation. Figure 6 shows the arrangement of all tables. Starting and Stopping To initialize a new task, the user adds entries to the appropriate tables through a console command and causes a dummy stack and stack pointer to be created. To stop a task, the last thing done in the task is to call a subroutine that would remove its task control table entry. This is equivalent to a CALL EXIT in FOR- TRAN found on many larger systems. 26 September 1979 © BYTE Publications Inc Circle 220 on inquiry card. North Star Announces — Double Density x 2 Sides = Quad Capacity! The North Star Horizon now delivers quad capacity by using two-sided recording on our new mini drives! That's 360,000 bytes per diskette! A four drive North Star system accesses over 1.4 megabytes of information on-line! Think of the application flexibility that so much information storage can give you! North Star has quadrupled the disk capacity of the Horizon computer but prices have increased a modest 15 percent. On a dollar per byte basis, that's a bargain that is hard to beat! The proven North Star disk controller was originally designed to accommodate the two-sided drives. North Star DOS and BASIC are upgraded to handle the new capacity, yet still run existing programs with little or no change. Of course, single sided diskettes are compatible with the new disk system. North Star Horizon Computer Prices (includes 32K RAM, one parallel and two serial I/O ports), assembled, burned-in and tested: Horizon-1-32K-Q $2565 Horizon-2-32K-Q $3215 Horizon-1-32K-D $2315 Horizon-2-32K-D $2765 et both sides now! Quad capaci! is available from your North Star dealer. ity fr NorthSlaf North Star Computers 1440 Fourth Street Berkeley, CA 94710 415-527-6950 TWX/Telex 910-366-7001 NorthStaf fe 285 on inquiry card. BYTE SeptemoeP CURRENT ACTIVITY INDICATOR COMMUNICATIONS CONTROL BLOCK (ONE FOR EACH TASK CONTROL TABLE ENTRY) I/O FUNCTION CODE I/O ROUTINE ADDRESS TO HANDLE THIS FUNCTION I/O PORT OR MEMORY MAPPED ADDRESS ASSIGNED TO TASK # n END OF TABLE MARKER (HEXADECIMAL FF) COMMUNICATIONS CONTROL BLOCK L — COMMUNICATIONS CONTROL BLOCK L- Figure 6: Control table organization. The current activity indicator contains the task number of the active task. The task control table contains the task number, task priority, last value of stack pointer, interrupt status flag (1 for yes, for no interrupts), and the pointer to the task's communications control block. The communications control block contains the I/O (input/output) function code, address of I/O driver routine associated with the function code, and the I/O port or memory mapped address assigned to the task for the particular function. One entry is provided for each function code used in the task. The owner of the task may add entries to the communications control block for specialized I/O driver requirements. Example The easiest way to show how all tables and pointers affect each other and the system is to observe them during a short period of machine ac- tivity. As we begin, task (the operating system and timeshare routines) has control, and a timer interrupt is occurring. There are 2 other tasks in memory: task 1 has priority 5 and task 2 has priority 4. First, as the interrupt routine is entered it saves all registers and flags of task on stack and saves the task stack pointer in the task task con- trol table entry (see figure 7). Next, it scans the task control table for the task of next highest priority, moves the new task number (task 1) to the current activity indicator, moves the task 1 stack pointer from the task control table to the processor's stack pointer, pops all of task l's registers and flags off of stack 1, and executes a return, which has the effect of pop- ping the program counter and jump- ing to that address. Task 1, while executing, en- counters a call to the I/O driver routine with a request for a keyboard input (see figure 8). When the I/O driver routine is entered, it scans the task control table to find the com- munication control block pointer entry for task 1 (the routine deter- mines which task called it by looking at the current activity indicator), then scans the communication control block for the function number entry corresponding to the one passed by the main program. Even though the computer may have 5 or more key- boards attached to it, the port address found in the communication control block gives it the address of the keyboard assigned to task 1. Since the keyboard read routine is a common one, the address referred to in the communication control block points to a subroutine located within the operating system area. Note that if the user had need for some special I/O subroutine, he could locate it in his own memory area and put the address in his com- munication control block as another function code. 28 September 1979 © BYTE Publications Inc Returning to the example, the keyboard read subroutine is called from the I/O driver, reads the keyboard port assigned to task 1, and returns to the I/O driver with the ASCII code. The I/O driver returns to the main program with the ASCII code in a register or memory loca- tion. In figure 9 the next timer inter- rupt has occurred, so control returns to the interrupt handler routine. Again, the interrupt routine saves all registers and flags of task 1 on stack 1, looks at the current activity in- dicator to see which program was last active, saves the stack pointer in the task 1 task control table entry, scans the task control table for the next highest priority task, and finds that task 2 should get control. The stack pointer for task 2 is loaded from the task control table, all registers and flags are popped off of stack 2 and again a return is executed that causes task 2 to take control. In the next step (shown in figure 10), task 2 has encountered the equivalent of a CALL EXIT or STOP command and has finished process- ing. This CALL EXIT calls a ter- minator routine which again finds out who called it (via the current activity indicator) and simply eradicates the task control table entry for that task. To keep things neat, all succeeding table entries are moved up 1 notch. Then, control is returned to the inter- rupt handler, which will find the next task in line. In this case, since no other tasks of lower priority are waiting, control is returned to the highest priority task 0. Error Handling On a single program system, error handling is something that the user can watch for manually. When several programs are running, the system must have routines to handle errors rapidly so that other programs will not be slowed down or destroyed. There are many common errors that are relatively easy to deal with. Executing an invalid op code or forgetting to put in the 2nd or 3rd byte of a multibyte op code can be handled through a simple system restart (through the interrupt handler routine) without losing continuity. But what about a program loop that accidentally destroys part or all of another user's program? On an IBM 360, all memory blocks assigned to a TRANSFER OF CONTROL DATA OR POINTERS Figure 7: Task has control of the processor and has just been interrupted. The inter- rupt routine looks at all pointers, saves the status, and then transfers control to task 1. task are given a unique 4-bit protect key (which is the same as the task number) that is stored in external hardware. One approach might involve having 2 external 16-bit registers that could be loaded by the interrupt routine with the high and low memory addresses of the active task. Then, every time the address bus has a valid address on it, it is tested against these registers. However, special precautions would have to be taken in those cases in which a utility in low memory (I/O driver routine etc) is called, or when memory map- ped I/O ports outside these address limits are used. ■ TRANSFER OF CONTROL : DATA OR POINTERS BOOTSTRAP LOADER „--- INTERRUPT ROUTINE 1 I/O DRIVER / ! * i — "■" '/ 1/ 1 / | /KBD/IN Jf' ) \ \0 1 \ ^ -* / CURRENT ACTIVITY INDICATOR s / / / S S . / / * TASK CONTROL TABLE COMMUNICATIONS CONTROL BLOCK . STACK 1 TASK 1 COMMUNICATIONS CONTROL BLOCK 1 STACK 1 __ ^^ Figure 8: Task 1 has requested keyboard input from its assigned keyboard. When the input is completed, the I/O (input/output) driver returns control to task 1. September 1979 © BYTE Publications Inc 29 = TRANSFER OF CONTROL ■ DATA OR POINTERS Figure 9: Task 1 has been interrupted and turns control over to the interrupt routine. Control is then passed to task 2. ■■ TRANSFER OF CONTROL . — = DATA OR POINTERS BOOTSTRAP LOADER INTERRUPT ROUTINE 1 CURRENT ACTIVITY INDICATOR N / TASK CONTROL TABLE ^ COMMUNICATIONS CONTROL BLOCK TERMINATOR STACK / * TASK 1 COMMUNICATIONS CONTROL BLOCK ONE STACK 1 TASK 2 COMMUNICATIONS CONTROL BLOCK 2 STACK 2 Resolving Allocation Conflicts Allocating I/O devices has been a problem since the early days of com- puters. Devices like tape drives and card readers (sequential devices) are nonshareable: only 1 program may use them at a time. However, disk drives are considered shareable, since the head may be positioned at ran- dom to gather data. The simplest method that can be applied to the system described in this article would be to have the initiator program check all communication control blocks to make sure that certain devices are not assigned more than once. I/O Software Considerations As mentioned earlier, I/O techni- ques in use on small systems leave all control up to the processor. If special timing is needed or if strobes or ready flags have to be checked, software is used instead of extra hardware, as in the case of larger systems. This in itself is good from the standpoint of economy, but requires that special care be taken when writing the driver and controller software. For example, suppose a cassette read routine uses a universal asyn- chronous receiver transmitter (UART) implemented in software as an algorithm instead of hardware. In a nonmultitasking system, the pro- gram may simply loop and time down between bits, but in a multitask system the timer interrupt would surely halt the activity and execute other programs. It may be well over 30 ms before it can return to the cassette read routine. It is easy to see what can happen to critical timing loops on a system that uses any kind of interrupts. The solution? If you must do the critical timing in software, it is necessary to turn off the interrupt timer while in the critical loop and reactivate it when in noncritical parts of the routine. If external hardware is used, and internal timing is reduced Figure 10. Task 2 has completed its execu- tion and encounters a CALL EXIT. Con- trol is given to the terminator routine which performs some cleanup operations and removes the task 2 entry from the task control table, effectively destroying the task. Control is then given to the inter- rupt routine which again scans the task control table to find the next task awaiting execution. 30 September 1979 © BYTE Publications Inc Circle 255 on inquiry card. DOUBLE DENSITY CUD SAVING Now you can put your S-100 system solidly into a full-size, single/double density, 600K bytes/side disk memory for just $1149 complete. DISCUS/2D™ single/double density disk memory from Thinker Toys™ is fully equipped, fully assembled, and fully guaranteed to perform perfectly. DISCUS/2D™ is a second generation disk memory system that's compatible with the new IBM System 34 format. The disk drive is a full-size Shugart 800R, the standard of reliability and performance in disk drives. It's delivered in a handsome cabinet with built-in power supply. The S-100 controller utilizes the amazing Western Digital 1791 dual-density controller chip . . . plus power-on jump circuitry, 1K of RAM, 1K of ROM with built-in monitor, and a hardware UART to make I/O interfacing a snap. The DISCUS/2D™ system is fully integrated with innovations by designer/inventor George Morrow. Software includes BASIC-V™ virtual disk BASIC, DOS, and DISK-ATE™ assembler/editor. Patches for CP/M* are also included. CP/M? Microsoft Disk BASIC and FORTRAN are also available at extra cost. DISCUS/2D™ is the really solid single/double density disk system you've been waiting for. We can deliver it now for just $1149. And for just $795 apiece, you can add up to 3 additional Shugart drives to your system. Both the hardware and software are ready when vou are. Ask your local computer store to order the DISCUS/2D™ for you. Or, if unavailable locally, write Thinker Toys,™ 5221 Central Ave., Richmond, CA 94804. Or call (415) 524-2101 weekdays, 10-5 Pacific Time. (FOB Berkeley. Cal. res. add tax.) *CP/M is a trademark of Digital Research. CSjMorrow makes disk memory for Thinker Toys " to noncritica] loops, the intervention of the multitask interrupt timer will not normally affect the system. If the interrupt timer causes an interrupt just before a byte is received by the UART but returns in time for the next byte to be received, the easiest way to assure that the cassette read routine does not drop a byte is to set the timing of the interrupt oscillator to at least twice as fast as the transmission rate of the UART. This greatly reduces chances of losing a byte. An alternate approach is to have even more hardware that forces the interrupt timer to timeout and return control to the program awaiting the data transfer operation when the in- coming data is present. A third way involves the use of direct memory ac- cess (DMA) capability, in which the external controller reads the UART and deposits the data directly into memory. With this approach, the calling program need only initialize the external registers and go into a wait state until the transfer is com- plete, allowing the rest of the tasks to execute normally. This last approach is used on many large systems and constitutes what is called a channel. Managing the System As you can see, many levels of ac- tivity are required to control a multiprogramming system properly. It is also apparent that some minimal hardware is required to prevent one user from obtaining exclusive control of the processor or writing over someone else's program or data. The use of control tables and a standard interrupt routine are also important as a way of letting the interrupt routines and I/O drivers know which task had control of the processor last. If the user plans to run BASIC soft- ware or some other kind of language interpreter, the safety features discussed earlier may be implemented as part of the interpreter. To run a lower-level operating system that allows the user to generate assembler level code will generally require the hardware described in this article, thus safeguarding the system and its users from accidental loss of pro- grams or data. In general, the use of timed interrupts allows for a fairly even distribution of processor activity, and depending on the cycle time of the host system, between 4 and 12 tasks may be handled without too noticeable a delay in response time.H REFERENCES Abrams, Marshall D, and Stein, Philip G, Computer Hardware and Software, Addison- Wesley, Reading MA, 1973. • Davis, William S, Operating Systems, Addison-Wesley, Reading, MA, 1977. Martin, Donald P, Microcomputer Design, Martin Research Ltd, Northbrook IL, 1976. Signetics Data Manual, Signetics Corpora- tion, Sunnyvale CA, 1976. Struble, George W. Assembler Language Programming: The IBM System 360 370, se- cond edition, Addison-Wesley, Reading MA, 1975. Tanenbaum, Andrew S, Structured Com- puter Organization, Prentice-Hall, Englewood Cliffs NJ, 1976. Fourth - ~ Anniversary Sale from the Originator of the TRS-80® Project FMG Corporation was formed in 1975 as a software consulting company. For the past 4 years FMG has been developing and in- troducing new programs de- signed to increase the versatility of the TRS-80. Last year we intro- duced the CP/M system, this year we offer the UCSD Pascal system. PASCAL UCSD Pascal. Ihe powerful general purpose language system, de- veloped for large and complex systems, is now available for your TRS-80. The FMG UCSD Pascal system opens a new generation of value for your TRS-80. Package includes: Operating System Screen Editor Z80 Macro Assembler Library Pascal Compiler Utilities and System Reference Book Price $150.00 (Requires 48k System with 2 drives.) Available without Macro Assembler, Linker and Library Price $100.00 FORTRAN Now On Sale! Comparable to compilers on large mainframes and minicomputers. All of ANSI standard FORTRAN X3.9- 1966 is included except COMPLEX data type. Therefore, users may take advantage of the many applica- tions programs already written in FORTRAN. Package includes: FORTRAN Compiler Macro Assembler (Z80) Linker Library Lib Manager (Not in TRS-DOS version.) Price $350.00 For this month only Sale priced at 250.00 Manual $25.00 (Specify TRS-DOS or TRS-CP M versions.) SID Symbolic Instruction Debugger Symbolic memory reference with built-in assembler disassembler. SID Diskette and Manual: Price $125.00 For this Month Only Sale Priced at $75.00 CP/M Operating ^ System New 1.46 Version Includes RS-232 and I O Byle im- plementation, Editor, Assembler. Debugger and Utilities for 8080 and Z80 Systems. For up to four TRS-80 floppy disks. Package includes: CP M System Diskette 5Vt" CP M Features and Facilities Manual CP M Editor's Manual CP M Assembler Manual CP M Debugger Manual CP'M Interface Guide Price $150.00 (Requires 16k and one drive minimum.) (Set of 5 Manuals $25.00) Updates for 1 .4 versions owners $15.00 MAC Macro Assembler Compatible with new Intel Macro standard. Complete Guide to Macro applications. MAC Diskette and Manual: Price $150 00 For this Month Only Sale Priced at $99.00 TEXTWRITER II A text formatting program that prints files created by an editing program. Contracts, personalized form letters and other documents can be printed from a stored library of standard paragraphs. Price: $130.00 For This Month Only Sale Priced at $75.00 Manual $25.00 TRS-80 N£\a, COMMUNICATOR RS232 Communication Program allows the TRS-80 to transmit or re- ceive programs or data files. Also makes the TRS-80 into a remote ter- minal. Requires Radio Shack RS232 and CP/M. $25.00 Call or Write for Complete Information n ^tart* CORPORATION A Division of Applied Data Corp P.O. Box 16020, B9 Fort Worth, Texas 76133 • (817) 294-2510 CP M is a regisleied Itademafh 0' Diqttai Research Co'ooratio" IRS B0 is a registered ''aden-aik Rad 'j snac* 32 September 1979 © BYTE Publications Inc Circle 134 on inquiry card. REAL ESTATE SOFTWARE 1$ ^7 i ii i . i i i i i i ■ i ^^ 1 1 1 i ^^p ^^^^^^\ i ^^^^^r i i l ^^^^^ ^^^^^^^^11 l l ll 1 1 1 T 1 Business Is Booming Over 240,000 Offices Nationwide And Still Growing! The Real Estate Market has never been so widespread, profitable and expensive labor costs, more and more real estate offices are relying business transactions. competitive! To beat competition and reduce upon computers to organize and direct their To meet this growing demand, R.S.I., Inc.™, has devel- oped the most comprehensive Real Estate Software ever that is specially designed to satisfy the needs of all Realtors . . . large or small. The software is easy to use and requires no training. R.S.I., Inc.™ , Real Estate Software is divided into 2 pro- grams. Property Management and Cash Flow Analysis (forthcoming). Each program comes complete with an instruction manual that features screen-by-screen displays. The Programs run on a DEC station 78 & 88 series, CP/M® operating system type 8080 or Z-80 with 48K of memory, C Basic 2 version 2.03, CRUN 2 version 2.03, 8 inch single or dual density floppy disks, a 132 character printer and CRT terminal with a 24 x 80 screen. MAIL COUPON OR CALL . TOLL— FREE (800) 227-3474 PROPERTY MANAGEMENT SOFTWARE Comes Complete With a 200 Page Instruction Manual. ..With 80 Screen-by-Screen Displays for Easy Reference! Program includes: * Operating Statement Report * Balance Sheet Report * Rent Book Report * Management Fees Report * Vacancy Report * Late Rent Report * Check Writing / Check Register * Deposit Register & much more... R.S.I.™ 's Software systems for the Real Estate market can be profitable for you. Inquire today for full details on Real Estate Software programs. circle 323 on inquiry card. Mail to: R.S.I.™ 2126 Lombard St. / San Francisco, CA 94123 I : Check enclosed Bill my Master Charge VISA Send me your PROPERTY MANAGEMENT software complete with 200 pg. manual for $595.00 (shipping & in- surance included / CA residents add sales tax). Acct.# Exp. date Signature Name Address City State Zip Telephone (include area code) DEALERS!... Check here □ and attach business card to coupon for complete details on all R.S.I.™ Software and merchandising support!! Interface a Chessboard to Your KIM-1 Jeff Teeters 1720 Coolidge Ct Eau Claire WI 54701 Chess is a fascinating game. Com- puter chess is especially fascinating because the complex analysis which determines each move is performed by a machine instead of a human. Computer chess offers an excellent way to demonstrate the power and versatility of personal computers. Most computer chess systems are unable to "see" a chessboard. A human playing against a computer will usually set up a chessboard beside the computer, and the moves will be communicated to and from the machine through the use of a keyboard and a display in some type of abstract notation. Keyboard entry of moves is unde- sirable. It is inconvenient, error prone, and inelegant. The abstract Photo 1: Two pawns, a White Knight, and a loose rivet are shown on top of the elec- tronic chessboard. One row of 8 light emitting diodes (LEDs) is placed along the left side of the board, and another row is placed along the bottom of the board as seen by the human player. Two LEDs are lit to indicate a single square, using an X, Y axis system. A single large hole is drilled in the center of each square to accept entrance of the rivet which is glued to the bottom of each chessman. The rivet completes an electrical circuit between 2 pieces of wire that run from smaller holes through the large central hole. This switching arrangement allows the computer to detect the presence or absence of a piece at each square of the board. In this prototype, an additional set of 3 wires is seen in each square; these wires remain from an earlier, unsuccessful switching attempt. notation promotes errors and makes play difficult for people who do not know the notation system. Further- more, errors may not be detected un- til many intervening moves have occurred. An ideal chess-playing system would contain a digital television camera to observe the board and a mechanical arm to move the pieces. [A mechanical arm designed for exactly this application was described in the article "A Hobbyist Robot Arm," by Keith Baxter and Timothy Daly in the February 1979 BYTE, page 84... RSSj A less costly alter- native is to construct a chessboard which can electronically com- municate with the computer. The computer may then "look" at the board position through its l/0(in- put/output) ports. A means of in- dicating the computer's moves on the chessboard itself may also be pro- vided. In the system that I have con- structed, the user makes his move on the electronic chessboard, instead of typing each move on a keyboard. The computer's moves are displayed on the chessboard through the use of discrete light emitting diodes (LEDs), arranged in an X,Y coordinate sys- tem. The LEDs show the user exactly which chessman the computer wants to move, and to which square. In addition to being aesthetically pleasing, this system makes it im- possible to enter your move in- About the Author Jeff Teeters is an undergraduate student at the University of Wisconsin at River Falls where he majors in mathematics. 34 September 1979 © BYTE Publications Inc correctly, and easy to interpret the computer's move. The board is continuously scanned so that even if the user moves the computer's piece incorrectly, the mistake is detected immediately. A speaker is connected to the computer to let unwary users know (by a buzz) when they misinter- pret a computer move. This speaker also emits a brief sound when the chess program has decided on a move and when it has been recorded into the computer's internal board representation. This project is designed for specific use with Peter Jenning's Microchess, running on a KIM-1 with about 0.5 K bytes of extra memory. Imple- mentation on other 6502 based com- puter systems should be relatively easy since only a few minor software modifications would be needed. The required hardware consists of a chess set, a package of cheap switching diodes, 2 integrated circuits, 16 discrete LEDs and 32 copper rivets. The chessboard should have a thin, nonconductive surface that is easy to drill holes through. This surface must be supported by side panels so there is a hollow space of about 2 cm under the board for wiring. I used a cheap plywood chess set that is designed to fold into a storage box for the chessmen. The copper rivets should be small in diameter, about 12 mm long, and have a flat top. The ones that I used were size 9 rivets manufac- tured by the Tower Corporation of Madison IN. System Concepts KIM-1 Microchess uses an internal board-status table to keep track of the whereabouts of the chessmen. This table contains 32 square numbers which indicate the position of the 32 pieces. It is important to realize that Microchess generates moves solely on the basis of what is in that table, and not how it was placed there. My plan of attack was simple. I had only to wire a chessboard to the computer and write an interface program that would translate moves on the chess- board into changes in the table. Since this program will be needed only when moves are physically being made, it can be called from Microchess and used in place of the Microchess keyboard I/O (input/out- put) routines. After the user has finished moving, control can be Photo 2: The bottom of the chessboard. The switching diodes and connecting wires are soldered directly to the wire contacts in the central holes. The 2 integrated circuits are type SN74154 decoder/demultiplexers. Note the tips of rivets protruding through some of the holes. transferred back to Microchess to compute the machine's next move. The Microchess to chessboard interface program is logically straightforward. If no move is being made, the table should be an accurate representation of the board. A move is detected when the table does not correctly represent the current board position. If an empty square appears on the board where the table indicates that a chessman resides, then the user has just picked up that man. If the table shows an unoccupied square which the board indicates is occu- pied, a chessman has just been set down in that square. A move is con- stituted by the user picking up a man and setting it down in some other location. A capture is completed by picking up 2 men and setting 1 down in the space formerly occupied by the other. Because the Microchess table is updated each time a simple move or capture is made, the table always gives an accurate representation of the current board position. Hardware Details Note that the chessboard interface program can keep track of the moves that are made simply by knowing if individual squares are occupied by a piece or are empty. The circuit which Photo 3: The complete chessplaying sys- tem. The completed electronic chessboard stands in the foreground. The chessboard and the sound-effect speaker are con- nected to the KIM-J computer residing in the suitcase in the background. provides this information to the com- puter is illustrated in figure 1. For purposes of square identification, the chessboard is conceptually cut in half. The 2 pieces are placed logically end to end, forming an arrangement September 1979 © BYTE Publications lnc 35 2.S0/ BREAKING THE SOUND BARRIER THE TRAP DOOR 33s6BT September 1977 March 1979 Byte Cover Prints - Limited Editions. The September '77 and March '79 covers of BYTE are now each available as a limited edition art print, personally signed and numbered by the artist, Robert Tinney. These prints are strictly limited to a quantity of 750 for each cover, and no other editions, of any size, will ever be published. Each print is 18" x 22", printed on quality, coated stock, and signed and numbered in pencil at bottom. The price of each print is $25. This includes 1) a signed and numbered print; 2) a Certificate of Authenticity, also signed personally by the artist and witnessed, attesting to the number of the edi- tion (750), and the destruction of the printing plates; and 3) first class shipment in a heavy-duty mailing tube. To order your limited edition art print, mail the order form below. out and Send me "Breaking the Sound Barrier" prints at $25 each, and "Trap Door" prints at $25 each. I understand this price in- cludes Certificate of Authenticity and first class shipment. □ I have enclosed check or money order to Robert Tinney Graphics. □ Charge this to my Master Charge or Visa Card #_ Expires:. Ship my print(s) to: Name Address. City State. .Zip. Send order to: robert tinney graphics P.O. Box 45047 ■ Baton Rouge, LA 70895 o 36 BYTE September 1979 Circle 369 on inquiry card. CCS has everything to expand your Apple II Friendly Frankie's roadside Apple II stand has plenty to whet your appetite for expansion. So, if you're ready to have your Apple 1 1 computer interface with the outside world, wheel around to Frankie's stand today. Expand to your heart's con- tent with our full range of delicious ■ ' 5 accessories, including: prom modules, asynchronous and synchronous serial interfaces, arithmetic processors, program- mable timers, parallel interfaces, A/D converters, and Apple II compatible boards galore. Let Frankie connect your Apple II to the rest of the world faster, and for a lot less bucks. For all the mouth-watering details, contact our northern California headquarters or your local roadside computer store. If Frankie's out, ask for Dennis or Jerry. They'll be glad to help you. 'Apple II is a registered trademark of Apple Computers, Inc. . fRIENDLY FRAWK/f's FRESH APPLES A/0 PROM MODULE HK3*' ,V«M1EL tf«TH«£ 7/c Circle 38 on inquiry card! California Compute 309 Laurelwood Road, S&nta Clara m /-~ Systems 95050', (408)988-1620 So Nobody Goes Away Mad. CA BYTE September 1979 37 + 5V 4 PB-I O PB-2 < \ PB-3<0 PB-4< \ 3.3Kn(4) ROW 2 PA-I O PA-2| ^> PA- 3 Q> PA-4| ]> Figure 1: Circuit which determines whether or not a given square is occupied. The chessboard is conceptually cut in half. It is placed so that the squares form a 4 by 16 matrix. For each square, a diode and a switch are wired in series between the appropriate row and column lines. A closed switch indicates an occupied square; an open switch indicates an empty square. of 4 rows and 16 columns. A diode matrix allows the hardware to iden- tify the individual squares. The integrated circuit in figure 1 is a type SN74154 4 to 16 line decoder/ demultiplexer. The 4 input lines to the device are connected to the KIM-1 I/O port A. Each of the 16 output lines is linked to a column in the matrix. This portion of the circuit allows the KIM-1 to select 4 squares out of the total of 64. The 4 rows of the matrix are connected to the I/O port B. Row and column addressing allows scanning of a single square. Each square of the chessboard has a switch. A closed switch indicates that the square has a piece on it; an open switch shows that the square is empty. To determine whether or not a piece is on a particular square, the interface program first selects the column by sending the correct binary code to the 4 input lines on the SN74154. This brings 1 of the 16 out- put lines low, while the diodes keep the rest high. If the switch is closed (ie: a piece is on the square), then the corresponding row-line will be pulled low and the matching port-B data register bit will be a 0. Thus, by select- ing the column through port A and testing the row bits in port B, it is possible to determine the status of every square on the board. Switch Experimentation Now for the hard part: what can be used as a switch? The actual mechani- cal operation remains the only unre- solved detail. All that is needed is some means of closing the switch whenever a piece is set down, and opening it when one is picked up. There are several ways to accomplish this — some of which are better than others. In my first attempt I put aluminum foil on the bottom of the pieces and used simple wire contacts on top of the board. I punched 6 holes into each square using a large needle to form the corners of 2 concentric, equi- lateral triangles. Three strands of wire were looped through the holes forming 3 symmetric contacts (see figure 2a). The third contact was used only to balance the pieces. The concept is simple. The piece is set on top of the wire contacts and the aluminum foil makes the necessary connection. Unfortunately it didn't work. The contacts were not suffi- ciently stable, and the slightest vibra- tion rocked the pieces, leading the program to believe that the user was trying to move 5 or 10 pieces at once. That problem might have been solved by mounting magnets on the pieces and using a chessboard with a nonconductive magnetic surface. 38 September 1979 © BYTE Publications Inc IVe finally found a personal**** s w*« g / _ Mr that professionals £*f % tW 1%M 1 ■'tf^J* II f*06'f^l-^ft~*l" get excited about the Compucolor II. It's V^W*A|#l*i^* *■ E CSUCtU a totally-integrated 8080 A system £ /VtYl~f^l l^f^l/Vf* I with full color graphics display, built-in 5 IK mini- %^%WAM;jLF MV^vMVFI. 11» di s k drive, and the best cost performance ratio available in a personal computer. The complete system is only S 1595.*And that price includes 8K user RAM. RS-232C compatibility and random access file capabilities. Our 8 foreground and background colors will boost your comprehension, while introducing you to an exciting new dimension in BASIC programming. The vector graphics have 16,484 individually-accessible plot blocks. And the 13" diagonal measure screen gives you 32 lines of 64 ASCII characters. You also have the flexibility that comes with 16K "Extended Disk BASIC ROM. Compucolor II offers a number of other options and accessories, like a second disk drive and expanded keyboard, as well as expandability to 32K of user RAM. Of course we also have a whole library of low-cost Sof-Disk™ programs, including an assembler and text editor. Visit your nearest computer store for details. And while you're there, do some comparison testing. With all due respect to the r==i others, once you see it, you'll be sold on the compucolor ii. I _J Corporation 1 t:;:e lIft :grfe6oes KLINGONS -di..V^ (\ > !7 7 II i « ST* DATE I tSU /ompucolor Cor^ Post Office Box 569 No eorgia 3007 1 Telephone 404/449-5996 Circle 56 on inquiry card. BYTE September 1979 39 COLUMN Figure 2a: The first attempt to form a switch for the squares. Three symmetric contacts on top of each square were made by looping bare wire through holes in the board. Two of the contacts were wired to the row and column lines on the back side of the board. (The third wire was simply to balance the piece upright.) The pieces had aluminum foil glued to their bottoms. When such a chessman was set down on the contacts, electrical continuity was achieved. Unfortunately, vibration caused intermittent contact and confused the computer. COLUMN Figure 2b: The second attempt to form a square switch. This attempt was successful. Copper rivets were glued to the bottom of the chessmen. A large hole was drilled in the center of each square to receive the rivet. Two wires were looped through the large central hole from 2 smaller holes (left over from the first switch attempt). The rivet closes the elec- trical circuit. ROW COLUMN Figure 2c: Illustration of the appearance of a square which uses rivet switches, and which previously did not have other methods installed in it. The reader may do it correctly the first time. Another possibility would be to eliminate wire contacts entirely and use reed switches or some type of photocell. Unfortunately, one such device must be mounted under each square, necessitating a total of 64 devices. Although they would have undoubtedly worked, 64 photocells or reed switches would have cost more than I was willing to spend on the project. Switch Success I eventually figured out a contact method that was both cheap and reliable. I drilled a small hole in the center of each square, just large enough to slide in a copper rivet. Two strands of bare copper wire from 2 of the inner contact holes used in my first attempt were looped through the larger central hole forming 2 contacts inside of the hole (see figure 2b). The felt on the bottom of the pieces was peeled off and the tapered copper rivets were glued onto the metal weight underneath the felt with an in- stant bonding adhesive. I have found that these contacts work quite well. The tapered copper rivets slide easily in and out of the hole, while slight pressure from the sides of the hole forces the rivet to make good contact with the copper wire. The pieces remain intact and the electrical contacts remain solid, even when the chessboard is held upside down and shaken gently. Of course when you wire your chessboard, you should leave out the 3 symmetric wires that I tried on my first version. Only the 2 strands which were looped through the rivet hole need to be in- stalled (see figure 2c). Hardware for Computer Output The LEDs are wired according to figure 3. The integrated circuit is another 4 to 16 line decoder whose 4 inputs are connected to the I/O ports. Note that decoder outputs thru 7 are connected sequentially to the rank — indicating (Y axis) LEDs with the 0-bit output being connected to the uppermost LED. Likewise, the file — indicating (X axis) LEDs are connected left to right with outputs 8 thru 15. The chip-enable line is con- nected to I/O port pin PBO so that the LEDs can be turned off while Micro- chess is computing a move. Mounting of the LEDs on the sides of the chessboard is relatively straightforward. I used a large needle to punch the holes for the leads prior to insertion. Glue can be used to hold them in place. Be sure to orient the chessboard so that a white square is in the lower right-hand corner of the side facing the human player. This means that the 2 rows of LEDs install- ed on the left side and bottom of the board will meet at a corner contain- ing a black square. The speaker is connected to output port pin PAO in the manner described in the K1M-1 User's Manual on page 57. See figure 4 for an illustration of the I/O port connections. Software The necessary modifications to Microchess are shown in listing 1. The Microchess to chessboard inter- face program with source and object listing is given in listing 2. Although I used a nonstandard meta-assembler, most of the mnemonics are similar to, if not the same as, the MOS Techno- logy standard mnemonics. The listings are fairly well documented. There are, however, some general concepts that may be difficult to deduce from the listings. The workhorse of the chessboard inter- face program is subroutine GET- MOVE. GET-MOVE calls the KIM monitor routine GETKEY before doing anything else, in order to see if the user has pressed the DA key (which is used when setting up a new position) or the PC key (which clears 40 September 1979 © BYTE Publications lnc Y AXIS I-5V 3 k k k k 00 02 04 05 06 G 20 1 1 II 1 ..... 13 1 15 1 17 i G 22 24 26 2 1 31 32 j 33 35 1 37 3 1 40 I "" 42 44 § 46 | 4 1 51 53 55 57 5 1 60 62 63 J 64 66 6 i (3 8L ■ -I 73 74 75 77 fSh 1*1 r€h A pSh r€h A [€fp 6 17 7 8 9 IC i 3 4 5 12 3 4 5 6 7 8 9 10 II 12 13 14 I5 y OUTPUTS INPUTS ICI SN74I54 Gl G2 ABC! ) KIM- 1/0 PORT 1 1 PB-0 O 1 PA-5 \Z> 1 PA-6 O 1 PA-7 £> 1 pb-5 r> l> 9 IS 23 22 21 20 X axis" I Figure 3: Circuit for lighting the light emitting diodes (LEDs) that indicate the computer's move. The computer moves as follows. The program lights the X and Y axis LEDs which together indicate the single square on which the piece to be moved resides. The per- son picks up the indicated piece. After the user picks up the piece, different LEDs light up that point to the square to which the piece is to be moved. The person then places the chessman as indicated. A mistake causes the computer to emit a characteristic sound. The chip-enable line of ICl is connected to I/O (input/output) port pin PB so that the LEDs may be turned off while the chess pro- gram is computing its next move. September 1979 © BYTE Publications Inc 41 the board for a new game). If neither square by square, searching for pieces the DA nor PC key is depressed, that were recently picked up or set GET-MOVE scans the chessboard, down. This is done by comparing the Bfl SPEAKER TO ) CHESSBOARD COLUMNS ) TO LEDs TO } CHESSBOARD ROWS Figure 4: Schematic diagram of chessboard input connections for the KIM-1. If the speaker is built into the chessboard, a 16 conductor cable is required to connect the board to the KIM-1 application connector. Thirteen conductors control the chessboard and light emitting diodes; 3 are needed for speaker, ground, and +5 V supply. The cable should be of sufficient length that the chessboard may be set in a convenient posi- tion for game playing. Microchess board-status table to the current board position, as pre- viously described. There is one im- portant exception. When the user picks up a piece to make a move, SHOULDBEUP-FLAG is made non- zero, and the square where the piece used to be is stored in hexadecimal addresses FA and F9. A nonzero SHOULDBEUP-FLAG tells sub- routine GET-MOVE that the 2 squares in FA and F° should not be occupied, even if they are shown in the table. This is done to prevent GET-MOVE from continuously reporting that the same piece was picked up. Upon exit from the subroutine, the result of the search is stored in the accumulator and in location UP- CLEAR-DOWN. A +1 is returned if a piece has been picked up, a if there is no change, and a —1 if a piece was set down. If a piece was picked up or set down, then CHANGING- SQUARE will contain the number of the square where the pickup or set- down occurred. Likewise, if a piece was picked up, then CHANGING- PIECE will contain the hexadecimal designation of that piece as outlined on page 3 of the Microchess player's manual. While GET -MOVE is scanning the chessboard, it also lights up the X and Y axis LEDs that point to the square in LIGHT-SQUARE. If SPEAKER- FLAG is nonzero, the speaker is rapidly toggled to produce a hum. Subroutine CLEAR-STACK resets the Microchess and the machine stack pointers back to their initial values. The subroutine is called from various parts of the interface program to pre- vent the stacks from overflowing into Microchess code. After Microchess has computed each move, control is transferred to the start of the interface program at hexadecimal address 2000. The user must physically move the pieces for the computer. The piece designation and the from and to squares of the calculated move are stored in the KIM display at hexadecimal addresses FB, FA, and F9 respective- ly. Because of the no-operation in- structions inserted at address 03E1, the move has not been recorded in the board-status table. Addresses 2010 through 2040 of listing 2 contain code Text continued on page 46 42 September 1979 © BYTE Publications Inc Circle 256 on inquiry card.. I 'niter „ . . _ _ 'b U, I 1 U A __J LI 1 1 i i I i i I .' —a £ ' ■" " p " r ^ ' ASS r^APff _ CopyrioM l t V7El O Morrcw. ~ , IJLUJUIAIJAIlJUlJULM,RJl<>,lBHII,MSS,tl^^^M - • M mm muni iiiuiii -- mm* *««** mum SK- tifel & * t-- n — . — * — -£■- « -- mum mum mum ^ : * ™ ; * rzi * * . n - . — . . IHMI . . . . " . . . . . . llllllll HIIIIII ' ' , ;■ iimlii ! - ■ liiiini . • J I ,;. I liimti ^^B ^^^^^^^^^^^iMMl^^i^ll^l^M^^^^i^^^i^^^iiw^^^^^^^^^^^^^^^^^ Jl*^: ■-. -. 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N.Y. 12958 Listing 1: Modifications which were made to Peter Jennings' KIM-1 Microchess program to allow for the use of the electronic chessboard. Change the specified locations in memory with the KIM monitor. Address (Hexadecimal) New Code (Hexadecimal; 0008 000A 00OD 000F 0012 0033 003F 00B7 00B9 01AC 03A7 03E1 03 E9 03EC A9 FF 8D 01 17 A9 21 8D 03 17 4C 00 20 00 60 02 04 08 10 60 B1 EA EA EA 20 39 00 4C 00 00 Comments Set up Port A-DDR Set up Port B-DDR Jump to interface program Toggle, must be - 1 or zero Return from CLDSP MASK-TABLE (used to read row) Return from DISP Use. SQUARE for flag Don't record move Show all FFs (Concede defeat) Listing 2: The Microchess to chessboard interface routine, a sort of chessboard device handler program. This listing is the output of an assembly with both source and hexa- decimal object code shown. It is written in a nonstandard assembly language of the author's own design, although most of the mnemonics are similar to the MOS Technology standard mnemonics. 0000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2002 2004 2006 2006 200A A? 00 85 2F A5 FA 85 2B E6 2E SET BIGC;0RG 2000; COMMENT *** KIM-1 MICROCHESS TO CHESSBOARD INTERFACE *** PROGRAM. URITTEN BY JEFF TEETERS. 9/8/78 DEFINE -BOAKll=50, .6D-t=4F, .BK=40, .SF2=B2, .SQUARE'S!, CHANG1NG-SQUARE CHANGING-PIECE CLDSP-3900, CLEAR-BUARD=180 C0UNT-FLAG=29, DISP=9D0I, FLASH-DISPLAY=1 FR0M-SQUARE=2A, GETKEr = 4Alf , G0=A203, LlGHT-SQUARE=2B MASK-TABLE=B?, H0VE=4B03, P0RT-LIGHT=2C, P0RT-SQUARE=2D, P0RT-A=0O17, P0RT-B=0217, RAND0h»=O417, REVERSE=B202, SPEAKER-PLAG=2E SHOULDBEUP-FLAG SUnCH-FLAG = 30, TCHAN6ING-PIECE TL'HANGING-SUUAR TEMP=F3, TBGbLE=33, TUP-CLEAR-D0U UH0vE=3103, UP-CIEAR-D0UN -♦"=12, =2?, 28, 0, F1F, X ADDRESS UF PIECE I ABLE X .BOARD LESS ONE X ADDRESS OF USERS PIECES Z MICROCHESS STACK POINTER X TO SQUARE USED BY MOVE X RETURNED BY 6ET-M0VE X PIECE PICKED UP AT CH-SQR 2 LLEAK DISPLAI X SET UP NEU GAME X SEI UHLN CUUNUNG D0UN X DISPLAY PIECE NAME IN FB X KIM MONITOR ROUTINE i USED UHEN UNM0VING CAPTURE X KIM MONITOR ROUTINE X ADDRESS OF CHESS PROGRAM X SQUARE LIGHTED BY LEDS X USED TO READ R0U X ROUTINE TO UPDATE .BOARD X USED TO BUILD 10 PORT X X KIM- I 1/0 PORT 2F, -31, E=32, 34, 5, KIM-1 1NIERVAL TIMER RUUIINE TO EXCHANGE SIDES = 1, GET-MOVE GENERATES TONE =1, SQUARES IN FA X F9 UP SET IN tXCHANGE X TEMPURARY CHANGING PIECE X IEMPORAKY CHANGING-SUUARE TEMPORARY STORAGE L0CAI10N ALTERNATELY LIGHTS FA i F9 TEMPORARY UP-CLEAR-D0UN ROUTINE TU UNMAKE MUVE STATUS OF CHANGING-SQUARE RETURN VALUE OF PLUS KET XXXXXXXXXXZXXZXXZXZXXXXXZIZZXXXXXZX7.1XX7.XZXXZXXZXXXX XXXXXXXXXX USER MOVE COMPUTER PIECE XXXXXXXXXX IXXXIXXXXXZXXXXXXXXXXXXZZXXXXZXXZXZXXZZIZXXIZZXIZXZX 2****4**** PICK THE PIECE UP »********J| PICK-IT-UP: L U AM 00 S(A SHOULDBEUP-FLAG FA L1GHI-SQUARE SPEAKER-FLAG LDA STA INC LOOP XRESET FLAG XLlGHl "PKUM SQUARE" XS0UND OFF 44 September 1979 ( E' BYTE Publications Inc Circle 278 on inquiry card. 200A 20 6B 21 JSR GET-MOVE XUAIT FOR PLAYER TO 2001 FO BED XZPICKUP PIELE. 200E FB ENDLOOP 200F 30 F7 BH1 PICK- 11 UP XERkOR, PItCt SET DOUN 2011 A5 27 LUA LHANGING-SQUAKE 21S P1LLE PICKED UP 2013 C5 FA CMP Fh XZC0RREC1 ONE? 2015 DO F1 BNE PICK-1TUP 2017 A6 FB LDX FB XYES, SET TABLE ENTRY 201? A? CC LOAD CC 7.1 10 "CC" 20IB ?5 50 STAX .BOARD 201D £****«**** SET THE PIECE DOUN ******♦**£ 20ID A5 F? LDA F? ZLIGHI TO SQUARE 20 IF 85 2B S1A LIGHT-SQUARE 202! E6 2E SET IT-DUUN: INC SPEAKER-FLAG XHAKE NOISE 2023 LOOP 2023 20 6B 21 JSR GET-MOVE XUAIT FOR CHANGES 2026 F0 BEQ 2027 FB ENDLOOP 2028 A5 F? LDA F? XIS USER MOVEING 202A C5 17 CMP CHANGING- SQUARE XXCCJRRECT FIECf' 202C DO F3 BNE SET-IT-DUUN 202t A5 35 LDA UP CLEAR-DOUN ZYES 2030 10 08 IF NEGATIVE THEN 2032 A6 FB LDX FB ZUPOATE TABLE. (PIECE 2034 A5 27 LDA CHANGING-SOUARE ZXSET DOUN, MOVE HAS 2036 ?5 50 STAX .BOARD ZXBEEN COMPLETED.) 2038 10 BPL 203V 08 ELSE 203A A6 28 LUX CHANGING-PIECE XCAPTURED PIECE HAS 203C A? CC LDAtl CC ZXBEEN PICKED UP... 203t ?5 50 STAX .BOARD ZXUPDATE TABLE AND 2040 30 DF BUI SET-IT-DOUN XXUAIT FOR SET DOUN. 2042 ENDELSE 2042 nzzzzzzzzzzzzxxxzzzxzzxxzxxxxxzxxxzxxzzxxzxzxxxxxxx 2042 zzzzzzzzzxx user moue user's FIECE XXZXXXZXXX 2042 zzzzzzzxzzzzzzzzzzxzzzzzxzxzzzzzxzxzxzxzxzxzxzxzxxxz 2042 t6 2E INC SPEAKER-FLAG ZMAKE NOISE 2044 A? 00 UAIT-FOR-HOVE: LDAK 00 XCLEAR UP FLAG 2046 85 2F STA SHOULDBEUP-FLAG 2048 85 2? SET -COUNT: STA COUNT-FLAG XSET COUNT FLAG 204A 20 3? 00 SET -D1SPLAV: JSR CLDSP ZCLEAR DISPLAY 2041) 20 6B 21 GET -MOVE1: JSR GET -MOVE 2050 DO 41 IF ZERO THEN 2052 Z7.ZXZXXXZXZZXZXZXZXZXXXXXZX ZXZXZXXZXXXZXZXZXX 2052 ZZZXXZZX NO CHANGE IN BOARD XXXXXXXZ 2052 zzzzzzxzzzzzzzzzzzzzzzzzzzzzzzmzxxzxzzzzzxz 2052 It******** CHECK FOR "GO " KEY **<*******% 2052 20 6A IF JSR GEIKEY 2055 C? 13 CNPtt 13 XI3=VALUE OF "GO" KEY 2057 FO 1/ BEQ GO-COUNTDOUN 205? It******** CHECK FOR "E" KEY «**+****»X 205? C? OE CMPH OE 205B DO 16 IF ZEKU IHEN XUSER UANTS IU 205D LOOP ZXSU1TCH SIDES 205D 20 6A IF JSR GETKEY 2060 C? OE CMPtt OE XDEBOUNCE KEYBOARD 2062 FO BEQ 2063 F? ENDLOOP 2064 AS 30 LDA SUI1LH-FLAG X10GGLE FLAG 2066 4? FF EORK FF 2068 85 30 STA SU1TCH-FLAG 206A 20 B2 02 SUIICH-SIDES: JSK REVERSE ZPERFORM EXCHANGE 206D 20 5D 21 JSR CLEAR-STACK 2070 4C 4C 21 60- ;0UNTD0UN: JMP START-COUNTING 2073 ENDIF 2073 X*t*****« "uO" OR "E" NOT FOUND *+***+**Z 2073 A5 2? LDA COUNT-FLAG XLGUNTING DOUN? 2075 FO 12 IF NOTZERO THEN 2077 C6 FB DEC FB XYES. 207? A5 FB LDA FB 207B DO 06 IF ZERO THEN 207D 20 5D 21 JSR CLEAR-STACK XPLAY CHESS 2080 4C A2 03 JMP GO 2083 ENDIF 2083 A? OF LDAH OF XSTILL COUNTING DOUN, 2085 65 2B ADC LIGH1-SQUARE XZLIUHT NEXT SQUARE. 2087 DO BNE 2088 03 ELSE Listing 2 continued on page 46 FAMOS™ MULTI-TASKING DOS: • 8080/Z80 • Device independent file system • Multi-sessioning/spooling • Full user accounting • All files dynamic • Multi-user file security • Intersystem communications S100 BUS SUPPORT MVT-BASIC™ MULTI-USER COMPILER • Powerful file, string I/O • Chaining . . . parameter passing • ISAM/sort facilities • Random, sequential files • Machine language calls • Error trapping HARD DISKS SUPPORTED MVT-WORDFLOW™ MULTI-USER WORD PROCESSING SYSTEM • Concurrent data processing • Automatic field insertion • Global search/replace • Library file insertion • "Cutting & pasting'Vblock moves • Full WP printer support • Multiple printers/concurrent • Wordwrap/variable line spacing • All options under user control IMMEDIATE DELIVERY AVAILABLE TO MANUFACTURERS/ OEM FOR PRIVATE LABEL MARKETING MVT MICROCOMPUTER SYSTEMS INC. 9241 Reseda Blvd., Suite 203 Northridge, CA 91324 Phone: (213) 349-9076 ^/ September 1979 © BYTE Publications lnc 45 Listing 2 continued from page 45: 2089 All 04 17 ! 208C 208C 85 2B ! 208E A5 FB ! 2090 4C 4A 20 ! 2093 2093 10 49 ! 2095 2095 2095 2095 2095 A5 B2 ! 2097 C9 C8 ! 2099 F0 01 ! 209B A5 2A ! 20911 C5 27 ! 209F DO 06 ! 20AI 20 31 03 ! 20A4 4C 44 20 ! 20A7 20A7 20A7 20A7 20 6A IF ! 20AA C9 15 ! 20AC 10 IC ! 20AE C9 12 ! 20B0 DO OC ! 20B2 A5 FA ! 20B4 10 97 ! 20B6 A6 FB ! 20B8 A5 1 7 | 20BA 95 50 ! 2061 10 86 ! 20BE 20BE 85 F3 ! 20C0 A5 FB ! 20C2 0A OA ! 20C4 0A OA ! 20C6 05 F3 ! 20C8 85 FB ! 20CA 20CA A5 2,' ! 20CC 85 2B ! 20CE 85 F9 ! 20D0 A5 FB ! 20D2 29 IF ! 20D4 85 IB ! 20DA AA 20D7 B5 50 ! 20D9 B5 FA ! 20DB 4C 4D 20 ! 20DE 20DE 20DE ! 20BE 20DE 20DE A5 B1 ! 20E0 L9 CC ! 20E2 DO 05 ! 20E4 E4 B1 ! 20E6 4C 6A 20 ! 20E9 20E9 20E9 20 5D 21 ! 20EC A5 27 ! 20tE 85 1 A ! 20F0 85 F9 ! 20F2 8b 2B 1 20F4 20 9D 01 ! 20F7 A9 01 ! 20F9 85 2F ! 20FB 20FB 20 6B 21 ! 20FE FO 20FF FB 2100 2100 10 11 ! XUAITING FOR (1UVE... XXLIGHT RANDOM SQUARE LDA? RANUGMH ENDELSE STA LIGHT-SQUARE LDA FB JMP SET-DISPLAY ENDIF IF NEGATIVE THEN xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxr.xxxxxxxxnxxx XXXXXXXX NEU PIECE SE1 DOUN XXXIXXXX XXXXXXXXXXXXXXXXXXXXXXXXXXXIXXXXXXXXXXXXXXXXX j>«*M**»* TAKING BACK CAPTURE? *********Z LDA .SP2 CMP* C8 XUNLI01NU PREVIOUS IF NOTZERO THEN XI CAPTURE? LDA FR0H-S9UARE CMP CHANGING-SQUARE IF ZERO THEN JSR UHOVE X YES. JHP UHlT-FOR-MOVE ENDIF ENDIF 2!*********USER ADDING NEU PIECE**********?; JSR GEIKEY XUAlf FOR KEY ENTRY CHPH 15 XXilf HEX NAME UR " + " IF NOTZERO 1HEN CMPM "+" IF ZERO THEN LDA FA XFOUNP "+", ENTER NEU BPL GET-H0VE1 UPIECE INTO TABLE IF LDX IB XXNOT IN ALREADY LDA CHANGING- SQUARE STAX .BUARD BPL UAIT-FOR- flUVE ENDIF STA TEHF 2FUUND HEX DIGIT LDA FB U"OR" IT INTO ASL ASL XZPUIL NAHE. ASL ASL ORA TEHP STA TB ENDIF LDA CHAN&ING-SQUAKt ZBUiLU DISPLAY STA LIGHT-SQUARE STA F9 XUF9=SQUARE ON BOARD LDA FB XPU1 PIECE NAME IN ANDti IF URANGE STA FB UXFB=PIEL'E NAME TAX LDAX .BOARD STA 1- A XXXFA=TABLE EN1RY JHP GET- MOVE 1 ENDIF 7.XXXXXXXXXXXXXXXXXXXXXXXXXXXIXZXXIXXXXXXXXXXX XXXXXXXX PIECE PICKED UP XXXXXXXX XIXXXXXXXXXXXXIXXXXXXXXXXXXXIXXXXXXXXXXXXZXXX IW**M**M USER PLAY UHITE' **«*******X LDA .SQUARE JSEE IF USER MAKING CHP« CC XXTHE FIRST MOVE. IF ZERO IHEN INC .SQUARE ZYES, CHANGE .SQUARE JMP SUITCH-SIDES HAND EXCHANGE ENDIF X«*+t****** gAIT FOR CHANGt ♦*********% JSR CLEAR-S1ACK XLLtAK POSSIBLE JUNK LDA CHANGING-SQUARE STA FA ZDISPLAT SQUARE NUrt STA F9 STA LIGHT-SQUARE JSR DISP ZD1SPLAY PIECE NAME LDA* 01 STA SHOULDBEUP-FLAG XSET FLAG LOOP JSR GET-HUVE ZAUAIT M0VE2 BEQ ENDLOOP 2********* PIECE SET BACK DOUN **********% IF NEGATIVE THEN L sting 2 continued on page 48 Text continued from page 42: to light the correct LEDs and modify the board-status table as the user completes the computer's move. The speaker sounds briefly after each cor- rect step is completed. If a wrong piece is moved or a piece is set down on a wrong square, the speaker will hum continuously to signal an error. The logic for interpreting the user's move starts at location 2042. If COUNT-FLAG is 0, the user has not yet moved. Subroutine GET -MOVE is repeatedly called from location 204D in anticipation of the user's move. If the accumulator is upon return from GET-MOVE, then the board position remains unchanged and the user has not made a move. GETKEY is called to see if the user has de- pressed either the GO or E key. If the E key is depressed, the Microchess routine REVERSE is called to swap the user and computer entries of the board-status table. After the ex- change is completed or if the GO key is depressed, a branch is made to START-COUNTING at hexadecimal address 214C. Three provisions are made for a delayed return back to Microchess. COUNT-FLAG is made nonzero, a countdown is initiated by setting the display to OF, and control is then transferred back to address 204D where GET -MOVE is repeatedly called as before. After each return from GET- MOVE the display is decremented by 1 until it equals 0. This provides an approximate 10 second delay during which the user can make a new move or retract an old one. At the end of the countdown, a branch is made to the Microchess routine GO which calculates the computer's next move. If the GET-MOVE call at 204D returns a negative value then the user has set down a new piece, and control is transferred to address 2095. In an ordinary game of chess, putting a new piece on the board would be con- sidered cheating. I have allowed it here to prevent 2 possible problems. The first problem is caused by in- decisive players who change their minds while in the middle of a move. Suppose such a player picks up 2 chessmen, as if to capture, and then decides to set both down again. When the first man is set down the program will think that the user has completed a capture, modify the board-status 46 September 1979 '& BYTE Publications Inc MOVING DATA AT A SNAILS PACE BECAUSE YOU'RE FLOPPY BOUNDP Let Corvus Systems put you back in the race! O R O a S llfl C A T A L W». B1RECTORY DfilUE NUMBEB » m llAl mt ■ For TRS-80T, Apple* (including Apple Pascal), S-100 Bus— and now LSI-11. Fully compatible hardware/software. 10-million byte disk: IMI-7710. Proven Winchester technology. Z-80 based Corvus disk controller. Comprehensive disk diagnostics. Up to 4 disks per system. System $5350, add-on disk $2990. Corvus offers a complete systems solution to the mass storage problem of micro computers. In a package smaller than a briefcase, we provide an intelligent controller, disk, and personality module. Call or write today for additional information. Get up to speed with Corvus. Now! Corvus speaks Apple™ Pascal™! tTRS-80 is a registered trademark of Radio Shack, a Tandy Co. X Apple is a registered trademark of APPLE Computers, Inc. CORVUS SYSTEMS, Inc. 900 S. Winchester Boulevard San Jose, California 95128 408/246-0461 Circle 83 on inquiry card. BYTE September 1979 47 Listing 2 continued from page 46 2102 A5 27 ! LDA CHANGING-SQUARE XFROM SQUARE = 2104 C5 FA ! CMP FA XXTO SQUARE? 2106 DO 03 l IF ZERO THEN 2108 4C 44 20 ! JHP UAIT-FOR-MOVE XYES, NO MOVE MADE. 210B ENDIF 210B 85 B1 ! STA .SQUARE XNO, 2I0D 20 4B 03 I JSR MOVE XZRECORD MOVE, 2110 4C 4C 21 JHP START-COUNTING HAND COUNT DOUN. 2113 ENDIF 2113 XXXXIXIIXXXZXZXXXXXXXXXIXXXXIXXXXXZXIXXIXXXXX 2113 zxxxxzxx 2'nd piece picked up ixxxzxxx 2113 XZXXIZZXXXXXZZZXXZXXXXXXXXZZXZXXXXXXXXXXXXXXX 2113 X********* UAIT FOR SET DOUN **»*****#3I 2113 A5 27 LDA CHANGING-SQUARE 2115 85 F? STA F? XF?=TO SQUARE 2117 85 Bl STA .SQUARE 211? 2-UP: LOOP 211? A5 33 LDA TOGGLE ZFLASH LIGHTS FOR TO 2MB 10 06 IF NEGATIVE THEN HAND FROM SQUARES. 21 1 D A5 FA LDA FA 2I1F E6 33 INC TOGGLE 2121 FO BEQ 2122 04 ELSE 2123 A5 F? LDA F? 2125 C6 33 DEC TOGGLE 2127 ENDELSE 2127 85 2B STA LIGHT-SQUARE 212? 20 6B 21 JSR GET-MOVE ZUAIT FOR SET DOUN 21 2C FO BEQ 21 2D EB ENDLOOP 21 2E 10 2? IF NEGATIVE IHEN 2130 %********* PIECE SET DOUN *********J 2U0 A5 27 LDA CHANGING-SQUARE 2132 C5 F? CMP F9 3X-S = TO SQUARE? 2134 FO OC IF NOTZERO THEN XXNOPE, 2134 C5 FA CMP (A Z= FROM SQUARE? 2138 DO IF BNE ERROR-3 XXNOPE, ERROR 21 U A6 F? LDX F? 2I3C 85 F? STA F9 XTO X FROM SQUARES 21 3E 65 Bl STA .SQUARE ZREVERSED, SUITCH BACK 2140 H6 FA STX FA 2142 ENDIF 2142 A5 FA LDA FA ZSAVE FROM SQUARE FOR 2144 85 2A STA FROM SQUARE ZXUSE IF UNDOING MOVE 2146 20 ?D 01 JSR DISP ZSET .PIECE 214? 20 4B 03 JSR MOVE ZRECORD MOVE 21 4C 2********* INITIALIZE COUNT DOUN ********* 214C A? 00 START-COUNTING: LDAH 00 XCLEAR FLAG 2I4E 85 2F STA SHOULDBEUP-FLAG 2150 85 2B STA LIGHT-SQUARE 2152 A? OF LOAN OF XLUAC DELAY 2154 E6 2E INC SPEAKER-FLAG ZSOUNII OFF 2156 4C 48 20 JHP SET-COUNT 215? ENDIF 215? E4 2E ERROR-3: INC SPEAKER-FLAG XSOME TYPE OF" ERRUR, 215B DO BC BNE 2-UP XZUAIT UNTIL CORRECTED 213D 215D 215D 215D SUBROUTINE CLEAR-STACK: XRESETS BOTH STACK MARKERS 2I5D 68 A8 68 PLA TAY PLA ZSTORE RETURN ADDRESS 2160 A2 FF ?A LDXH FF TXS ZRESET MACHINE STACK 2143 A2 C8 LDX* C8 ZRESL1 CHESS STACK 2165 86 B2 STX .SP2 2167 48 ?8 48 PHA TYA PHA ZSET UP RETURN 216A 60 RTS 2I6B 2148 216B 214B ! SUBROUTINE GET-MOVE: XSCANS CHESSBOARD 216B ! UUXHUUUllllUUUXUlXlXUUUXXXUlZlU%lXTt.U 216B ! xxxxzxxzzzz check for "da" OR "PC" XXXXXXZXXZ 216B ! luxuuuxuxxuxxxiuvaiun XZXZXXXXXXXZXZXZZXXXl 2I6B 20 6A IF JSR GETKEY 216E C? 11 CHPK 11 XI 1 = "HA" KEY 2170 DO OB IF ZERO THEN 2172 A2 IF LDXH IF ZFOUND "DELETE ALL" Listing 2 continued on page 50 table accordingly, and proceed to countdown. During the countdown the second man would pop in and there would be no way to know what it was. In order to prevent this, each cap- turing move is saved in the Microchess stack. When a new piece is set down, the stack pointer is checked to see if the previous move was a capture. If it was, and if the location of the new piece corresponds to the square where the capturing piece used to be, then the Microchess routine UMOVE is called to restore the board-status table. The second problem arises when the user wants to add new pieces to the current board, or set up an entire- ly new board position. Previously the only way to add new pieces was to stop the chess program and enter the square numbers manually into the board-status table using the KIM-1 monitor. This method is both incon- venient and error prone. The control logic for the "new improved" method occupies hexadecimal addresses 20A7 through 20DE. After setting the new pieces down, the user simply types the piece name (its numeric designation) into the hexadecimal keyboard. The designa- tion is displayed in FB, the current board-status table entry in FA, and the square where the new piece was set down is stored in F9. If the current table entry is "CC" (indicating that the piece is not currently on the board), the user may enter the piece into the table by pressing the + key. Interpreting the User's Move If the original call to GET-MOVE at hexadecimal address 204D returns a positive value, it means that the user has picked up a piece, and con- trol will transfer to address 20DE. If .SQUARE contains "CC", the Micro- chess board-status table has just been initialized, and the user is making the first move of a new game. The board- status table has been initialized assuming that the user would play Black. A branch may be made to address 206A where the user and computer table entries are exchanged. After checking to see whether or not the user is playing White, GET- MOVE is again called at hexadecimal address 20FB. If the piece is set down at a new square, the move has been completed and a countdown is started. If, after picking up a piece a 48 September 1979 © BYTE Publications Inc The Paper Tiger At $995, why settle for less. The Paper Tiger sets a new stan- dard for low-cost impact printers. More capability. More versatility. ■ Eight software-selectable character sizes. ■ 80 and 132 column formats. ■ Full forms control. ■ DotPlot™ graphics option. ■ Connects directly to Apple II, TRS-80, and other personal computers. Plus lots more. For a free brochure, print sample, or the name of the Paper Tiger dealer nearest you, write or call. Integral Data Systems, 14 Tech Circle, Natick, Massachusetts 01760. Call toll-free 800-343-6412. In Massachusetts, Alaska, and Hawaii call (617) 237-7610. « Circle 176 on inquiry card. Integral Data Systems, Inc. Listing 2 continued from page 48: 2174 A9 cc LDAtt CC 2174 LOOP 2176 95 50 STAX .BOARD XFILL PIECE TABLE 217B CA DEX UUITH "CC" 2179 10 BPL 21 7A FB ENDLOOP 217B 30 1F BHI JMP-TO-HAIN 217D ENDIF 217D C9 14 CMP* 14 X14="PC" KEY 217F DO 21 IF ZERO THEN UIPLEASE CLEAR) 2181 20 18 00 JSR CLEAR-BOARD XSET UP NEU GAME 21S4 85 B1 STA .SQUARE XFLAG .SOUARE UITH CC 2186 A9 00 LOAN 00 ZCLEAR FLA6S 2188 85 2F STA SHOULDBEUP-FLAG 218A 85 30 STA SUITCH-FLAG 218C LOOF XUAIT FOR CLEAR BOARD 2I8C A5 27 LDA CHANGING-SQUARE 218E 85 F9 STA F9 XBISPLAY BAD SQUARE 2190 85 FA STA FA 2192 85 2B SfA LIGHT-SQUARE 2194 20 9D 01 JSR BISP XD1SPLAT PIECE NAME 2197 20 A2 21 JSR START-SCAN 219A DO BNE 219B FO ENDLOOP 219C 20 5D 21 JNP-TO-NAIN: JSR CLEAR-STACK IRESET STACK 21 9F 4C 44 20 JHP UAIT-FOR-HOVE 21A2 ENDIF 21A2 muzuuuuiuxxunuumuxmnuuuuuuu 21A2 UXUlUXll START SCANNING CHESSBOARD UXXIXXXXX 2IA2 XXXIZXXXZZIIZIXZZXXZXXIXIXIZXZZIXZXZXZXIXIXUZZZXXZX 21A2 X********* SET UP PORT-LIGHT **«******2 21 A2 A5 30 START-SCAN: LDA SUITCH-FLAG XSIDES EXCHANGED? 2IA4 FO 07 IF NOTZERO THEN 2IA6 A5 2B LDA LIGHT-SQUARE XYES, 2IA8 49 77 EORII 77 ZXPL=77-"LIGHT-SGUARE 2IAA 4C JHP 2IAB AF 21 ELSE XNU, 2 IAD A5 2B LDA LIGHI-SUUARt XXPL="tlGM r-SOUARL" 21 AF ENDELSE 2IAF 85 2C STA PORT -LIGHT 2IB1 Z********INITIALIZE U-C-D * TC-S****»***X 2IB1 A9 00 LOAD 00 2IB3 85 35 STA UP-CLEAR-UUUN 21 B5 LOOP 21 B5 85 32 STA fCHANGING-SQUARE 21B7 J<*********D0 MISCELLANEuUS 1/0**********2 21B7 20 IF IF JSR FLASH-DISPLAY IFLASH DISPLAY 21BA A5 2E LDA SPEAKER-FLAG 21BC FO 03 IF NOTZERO 1HEN 21 BE EE 00 17 INC9 PORT-A ITOGBLE SPEAKER 21C1 ENDIF 21C1 IXXXXXXXXXXXXXXXXUXXIXIXXXXXXIXXXXXXXXXIXXXX 21C1 XXXXXXXX IF SHOULDBEUP-FLAG NOf SET XXXXXXXX 21C1 XlllXllX SEE IF SQUARE IN PIECE TABLEXXIXXXXX 2IC1 zxxxxxzzzxxxxxxxzxxxxxxxxxzzxxxzixxzixxxxxzxx 21C1 A9 00 LDAtt 00 XASSUNE SQUARE OK 21C3 85 34 STA TUP-CLEAR-DOUN 21C5 A5 2F LDA SHOULDBEUP-FLAG JIN MIDDLE OF MOVE? 21C7 FO OA IF NOTZERO THEN 21C9 A5 32 LDA TCHANGING-SQUAREZYES, IS SQUARE IN 21 CB C5 FA CHP FA XXDISPLAY? IF SO 21 CD FO 15 BEQ NOT -IN-TABLE XXPRE1EHH THAT IIS 2ICF C5 F9 CHP F9 IXNOT IN PIECE TABLE. 2191 FO 11 BEQ NOT-IN-TABLE 21D3 ENDIF 21D3 X**********SEAKCH PIECE TABLE********** *X 21 D3 A2 IF LDXIt IF 21D5 LOOP 21B5 B5 50 LDAX .BOARD 21D7 C5 32 CMP ICHANGING-SUUARt 21D9 DO 06 IF ZERU IHEN 21 DB 86 31 STX TCHANGING-PIECE 21DD E6 34 INC TUP-CLEAR-DOUN ZFOUND SQUARE 21DF DO 05 BNE BUILD-PORTS 2tE1 ENDIF 21E1 CA DEX 2IE2 10 BPL Listing 2 continued on page 52 player decides to set it down on the same square, the move is ignored. If the GET-MOVE call at location 20FB reports that a second piece has been picked up, a capture is in pro- gress and control branches to location 2113. FROM-SQUARE is defined as the square from which the first chess- man is picked up. Similarly, TO- SQUARE is associated with the chessman that is picked up second. GET -MOVE is again called at hexa- decimal address 2129. If a piece is set down on either the TO or FROM squares then the pro- gram assumes that a capture has been made. The Microchess routine MOVE is called to modify the board- status table, and a countdown is ini- tiated. If a piece is set down on a square other than the FROM or TO square, or if a third piece is picked up, a branch will be made to hexadecimal address 2159, and the speaker will hum to indicate an error. Using the System Playing the chessboard-interfaced version of Microchess is easy. Moves are made by physically picking up the pieces and setting them down on a new square, as in a normal game of chess with a human opponent. The only difference is that the opponent (the KIM-1) is unable to pick up a chessman, so you have to move the pieces to the location indicated by the LEDs. The KIM display will be all Os and the LEDs will blink from square to square in a semirandom fashion when it is your turn to move. After you move, the KIM display will count- down from OF, and the Y axis LEDs will blink sequentially from the top to the bottom of the board. During this countdown you have the option to change your move. When the display reaches 0, the machine will begin computing a response, and no moves can be made until it is your turn again. Operating the System The interfaced version of Microchess is started at address 0000, just as the unmodified Microchess. The speaker will probably hum. To start a new game, press the PC key. The speaker's sound will cease. Choose the White or Black pieces, and set up the board with your choice 50 September 1979 © BYTE Publications Inc Solve your personal energy crisis. Power do the work. With a calculator, pencil and paper you can spend hours plan- ning, projecting, writing, estimating, calculating, revising, erasing and recalculating as you work toward a decision. Or with VisiCalc and your Apple* II you can explore many more options with a fraction of the time and effort you've spent before. VisiCalc is a new breed of problem-solving software. Unlike prepackaged software that forces you into a computerized straight jacket, VisiCalc adapts itself to any numerical problem you have. You enter numbers, alphabetic titles and formu- las on your keyboard. VisiCalc organizes and displays this information on the screen. You don't have to spend your time programming. Your energy is better spent using the results than gettirig them. Say you're a business manager and want to project your annual sales. Using the calculator, pencil and paper method, you'd lay out 12 months across a sheet and fill in lines and columns of figures on products, outlets, salespeople, etc. You'd calculate by hand the subtotals and summary figures. Then you'd start revising, erasing and recalculating. With VisiCalc, you simply fill in the same figures on an electronic "sheet of paper" and let the computer do the work. Once your first projection is complete, you're ready to use VisiCalc's unique, powerful recalculation feature. It lets you ask "What if?" examining new options and planning for contingencies. "What if" sales drop 20 percent in March? Just type in the sales figure. VisiCalc instantly updates a other figures affected by March sales. Circle 301 on inquiry card. Or say you're an engineer working on a design problem and are wondering "What if that oscillation were damped by another 10 percent?" Or you're working on your family's expenses and wonder "What will happen to our entertainment budget if the heating bill goes up 15 percent this winter?" VisiCalc responds instantly to show you all the consequences of any change. Once you see VisiCalc in action, you'll think of many more uses for its power. Ask your dealer for a demonstration and dis- cover how VisiCalc can help you in your professional work and personal life. You might find that VisiCalc alone is reason enough to i own a personal computer. VisiCalc is available now for Apple II computers, with 'versions for other personal computers coming soon. The Apple II version costs just $99.50 and requires a 32k disk system. For the name and address of your nearest VisiCalc dealer, call (408) 745-7841 or write to Personal Software, Inc., Dept. B, 592 Weddell Dr., Sunnyvale, CA 94086. If your favorite > .1 dealer doesn't already carry Personal Software products, ask him to give us a call. 0R0 TM— VisiCalc is a trademark of Personal Software, Inc. 'Apple is a registered trademark of Apple Computer, Inc. Listing 21E3 21 E4 21E6 21E4 21 E4 21E4 21E4 2tE8 21EA 21 EC 21EE 21 EF 21 F1 21F3 21F3 21 F5 2IF5 21F7 21F9 21FB 21FD 21 FD 21FF 2202 2203 2205 2207 220A 220C 220F 2211 2213 2214 221 B 221A 221B 2 continued from page 50: Ft ! ENDL0OP C4 34 1N0T-IN-TABLE: DEC TUP CLEAR-MIUN XSQUAKE NO! IN .BUAKD A5 30 FO 07 A5 32 49 77 4C F3 21 AS 32 85 2D A5 2C 30 04 OA OA OA OA 2V 70 EE 02 17 OA 85 F3 A9 01 2D 00 17 05 F3 8D 00 17 A5 2D 29 40 4A 4A 4A 05 2D 29 OF OA OU 00 17 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxixxxxxxxxxx xxxxxxxxx build i/o forts zmum zzmmmzmmmxxzmmmmnmzzzz X***»******SET UP PORT-SQUARE****»*«*«*+X BUILD-PORTS: LDA SUITCH-FLAG XSIDES EXCHANGED? IF N01ZER0 THEN LDA TCHANGING -SUUARt XrES, SET PS TO EORJ 77 ZX77-"TCH-SQUARE' JHP ELSE XNO, LDA TCHANGING -SQUARE ZXPS="TCH-SUUARE' ENDELSE STA PORT-SQUARE )>****++*****+***PfjR| - ft -ft ******** »***»■■* *X LDA PURT-LIGHI IF POSITIVE THEN *SL ASL XNEGATIVE=X AXIS, *SL ASL XFObITIVE=Y AXIS. ENDIF AND* 70 INC? PORT-B XDI5ABLE LEDS ASL XLON [ TOGGLE SPEAKER STA TEMP LUAtt 01 ANDfi P0R1 -A OKA TEMP STAB PURT-A XSTORE ALL BUT COLUMN LDA PORT-SQUARE AND* 40 LSR LSR LSR ORA PORT-SQUARE ANDI OF ASL 0RA6 PORI-A Listing 2 continued on page 54 of color placed closest to the bottom X axis LEDs. After the chessmen are in place, the display will show all Os. If you are playing White, make your opening move. If the computer is playing White, press the GO key. To set up the pieces in a new con- figuration, or to continue a game that was halted earlier, set the chessboard up with the chessman in their desired position. Start the chess program as described above, but instead of press- ing the PC key, press the DA key. Type in the name of each piece using the hexadecimal keyboard as you would when adding a new piece. Start the play by either making a move or by pressing the GO key. To add a new piece to the board, set the piece on the desired square. The KIM-1 display will show 3 bytes of information. The first byte will be a random piece designation (as described on page 3 of the Microchess player's manual). The second byte is the square that the piece is on, according to the Microchess board- status table. If the piece has been cap- tured, "CC" will be displayed. The third byte is the number of the square PET TRS-80 Compucolor II ADD SOUND TO YOUR BASIC PROGRAMS! Complete system includes hardware with connectors and software that provides all the tools for programming you need to make sound. You get: • a variety of sample sound effects and musical notes • directions to easily create your own sounds and tunes • complete instructions, including sample BASIC subroutines, for adding sound to any program. Also, SOUNDWARE SOFTWARE programs for 8K PET. SEE YOUR DEALER FOR A DEMONSTRATION. Suggested Retail: PET/TRS-80 $29.95 Compucolor S39.95 CAP Electronics, 1884 Shulman Ave. San Jose, CA 95124 (408) 371-4120 52 September 1979 © BYTE Publications Inc Circle 43 on inquiry card. PET / TRS-80 1 A PPLE: Personal Software brings you the finest! Ml CHESS The Industry's First Gold Cassette Over 50,000 Sold MICROCHESS is the industry's best selling computer game. And no wonder— because MICROCHESS gives you more than just a chessplaying program: A convenient, foolproof set of commands and error checks ... complete instructions in a 5V4" by &V2" booklet ... a cassette that's guaranteed to load, with disk versions coming soon ... and several levels of difficulty to challenge you not just once, but time after time. It's available through well over three hundred computer stores and many mail order sources ... always originating from Personal Software. What's more, every Personal Software product is selected to give you these same benefits of easy availability, reliable cassettes, readable documentation, a carefully thought out user interface ... and most important, continuing challenge and enjoyment, not just once but time after time. If you haven't already, order your own gold cassette: MICROCHESS, by Peter Jennings, for 8K PETs, 16K APPLEs, and 4K Level I and II TRS-80S $19.95 TIME TREK A Tour De Force In Real Time Action Strategy Games TIME TREK by Brad Templeton for 8K PETs and Joshua Lavinsky for 4K Level I and II TRS-80S adds a dramatic new dimension to the classic Star Trek type strategy game: REAL TIME ACTION! You'll need fast reflexes as well as sharp wits to win in this constantly changing game. Be prepared— the Klingons will fire at you as you move, and will move themselves at the same time, even from quadrant to quadrant — but with practice you can change course and speed, aim and fire in one smooth motion, as fast as you can press the keys. Steer under power around obstacles— evade enemy shots as they come towards you — lower your shields just long enough to fire your phasers, betting that you can get them back up in time! With nine levels of difficulty, this challenging game is easy to learn, yet takes most users months of play to master. ADD SOUND EFFECTS with a simple two-wire hookup to any audio amplifier; the TRS-80 also produces sound effects directly through the keyboard case, to accompany spectacular graphics explosions! You won't want to miss this memorable version of a favorite computer game $14.95 BLOCKADE by Ken Anderson for 4K Level I and II TRS-80s is a real time action game for two players, with high speed graphics in machine language. Each player uses four keys to control the direction of a moving wall. Try to force your opponent into a collision without running into a wall yourself! A strategy game at lower speeds, BLOCKADE turns into a tense game of reflexes and coordination at faster rates. Play on a flat or spherical course at any of ten different speeds. You can hear SOUND EFFECTS through a nearby AM radio— expect some razzing if you lose! 14.95 GRAPHICS PACKAGE by Dan Fylstra for 8K PETs includes programs for the most common 'practical' graphics applications: PLOTTER graphs both functions and data to a resolution of 80 by 50 points, with automatic scaling and labeling of the axes; BARPLOT produces horizontal and vertical, segmented and labeled bar graphs; LETTER displays messages in large block letters, using any alphanumeric or special character on the PET keyboard; and DOODLER can be used to create arbitrary screen patterns and save them on cassette or in a BASIC ELECTRIC PAINTBRUSH by Ken Anderson for 4K Level land IITRS-80s: Create dazzling real time graphics displays at speeds far beyond BASIC, by writing 'programs' consisting of simple graphics commands for a machine language interpreter. Commands let you draw lines, turn corners, change white to black, repeat previous steps, or call other programs. The ELECTRIC PAINTBRUSH manual shows you how to create a variety of fascinating artistic patterns including the one pictured. Show your friends some special effects they've never seen on a TV screen! $14.95 program $14.95 WHERE TO GET IT: Look for the Personal Software^ display rack at your local computer store. For the name and address of the dealer nearest you, call Personal Software at (408) 745-7841. If you don't have a dealer nearby, you can call or mail us your order with your check, money order or VISAIMaster Charge card number. For a free catalog, ask your dealer or use the reader service card at the back of this magazine. PERSONAL SOFTWARE INC. 592 WEDDELL DR. • SUNNYVALE, CA 94086 Circle 302 on inquiry card. BYTE September 1979 53 Listing 2 continued from page 52: 22IE 8D 00 17 STAB PORT-A XOR IN COLUMN 2221 I***«************P0RI-B*** : t********* : »***2 2221 A5 2C LDA PORT-LIGHT 2223 18 CLC 2224 4? 80 ADCfi 80 XTOGGLE PL FLAG BIT 2224 B5 2C STA PORT-LIGHT 2228 2? 80 ANDtt 80 222A 4A 4A LSK LSK XSET X UR Y AXIS ANH 222C 8D 02 17 S1A0 F'ORT-B XXENABLE LEDS 222F XXXXZXXXXXXZXXXXXXXXXXXZXXXXZXXXXXXXXXXXXXXXX 222F XXXXXXX DID STATUS OF SQUARE CHAN6ET XXXXXXX 222F XXXXXXl IF SO RECORD THE CHANGE XXXXX1X 222F xxxxxxxxxxxxxxxxzxxxxxxxxxxxxxxxixxzzxxzxzxzx 222F J*** + ***********REA[I R0U******«***«*****Z 222F A5 2D LDA PORT-SQUARE 2231 2? 30 ANim 30 2233 4A 4A LSR LSR 2235 4A 4A LSR LSR 2237 AA l TAX 2238 65 B7 I LDAX MASK-TABLE 223A 2D 02 17 AND* PORT-B 223D l***********CHECK FOR CHANGES************ 223D DO 04 l IF ZERO THEN 223F A5 34 LDA TUP-CLEAR-DOUN XSQUARE OCCUPIED... 2241 10 10 BPL NEXT-SQUARE XANB IN TABLE. 2243 30 BHI 2244 04 ELSE 2245 A5 34 LDA TUP-CLEAR-DOUN ZSQUARE EHPTY... 2247 30 OA BHI NEXT-SQUARE ZXAND NOT IN TABLE 224? ENDELSE 224? X**««»**F0UND A CHANGE, RECORD IT*******X 2249 85 35 STA UP-CLEAR-DOUN 224B A5 32 LDA TCHANGING-SQUARE 224D 85 27 STA CHANGING -SQUARE 224F A5 31 LDA TCHANGING-PIECE 2251 85 28 STA CHANGING-PIECE 2253 ZZXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXZXXXXZXXXXXXXZX 2253 XXXXXXXCHECK NEXT SQUARE OR RETURN IF ALL DONEXXXXXX 2253 XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXZXXXZXXXXXXXX 2253 E6 32 NEXT-SQUARE: INC TCHANGING-SQUARE XADD ONE TO 2255 A? 08 LDAH 08 XXTCHANGING-SBUARE 2257 25 32 AND TCHANGIN6-SQUARE 225? OA ! ASL 225A IB CLC 225B 45 32 ADC TCHANGING-SQUARE XADD "CARRY" 225D 29 77 AND* 77 XHASK OUT GARBAGE 225F 85 32 S1A TCHANGING-SQUARE 2241 F0 03 BEQ RETURN 2243 4C JHP XXXGO CHECK NEXT SQUARE 2244 B5 21 ENDLOOP 2244 A? 00 RETURN: LDA* 00 2248 85 2E STA SPEAKER-FLAG 224A EE 02 17 INC? PORT-B 224D AS 35 LDA UP-CLEAR-DOUN 224F 40 RTS 2270 END OF ASSEMBLY upon which the new piece was set down. Modify the first byte by typing in the correct name of the new piece. If the piece has been previously cap- tured, it may be added to the piece table by typing the + key. To change sides (Black to White, or vice versa), type the E key. A count- down will be initiated. Do not change sides before the opening move of the game; the King, Queen, and other pieces could become incorrectly reversed. Conclusion Although it may require a lot of solder, building the hardware is neither hard nor exacting work. As with most projects, if it doesn't work the first time the problem can usually be traced to an incorrect program, faulty wiring, or bad integrated cir- cuits. In this particular project, the program is already written, the wiring is easy to check, and there are only 2 integrated circuits. The electronic chessboard can, of course, be used for activities other than chess. Almost any game that is played with an X,Y type grid can be played by the computer, among these: checkers, tic-tac-toe, and nim. I have found that the chessboard interface makes playing chess with the KIM-1 much more enjoyable. Even if you lose the chess game, the method of playing is sure to be im- pressive. ■ Editor's Note The program described in this arti- cle was designed to be "foolproof" for the beginning chess player. The countdown period for changing a move will greatly ease the frustration often experienced by players of com- puter games, the sinking feeling of "Oh no, I didn't mean that, and there's no way to take back the move!" More programmers should pay such attention to the user inter- face of their systems. More experienced chess players generally abide by the following rule: a piece once touched by the player must be moved, and an opponent's piece once touched must be captured. Such users would probably wish to delete the countdown period to speed the progress of the game. An electronic chessboard operating in a similar fashion appeared in the article "Chess 4.7 versus David Levy" by J R Douglas (December 1978 BYTE, page 84). That board, con- structed by Dr David Cahlander of Control Data Corp, uses 1 light emit- ting diode (LED) in each square of the chessboard to indicate the computer's move, and uses magnetic switches placed under the squares which are activated by the metal weights in the pieces. Controlled by a 6800 micro- processor, Cahlander's board trans- mits and receives moves to and from a remote computer on which the Chess 4.7 program runs... RSS 54 September 1979 © BYTE Publications Inc page Precut Wire Wrap Wire PRECUT WIRE SAVES TIME AND COSTS LESS THAN WIRE ON SPOOLS Kynar precut wire. All lengths are overall, including 1 " strip on each end. Colors and lengths cannot be mixed for quantity pricing. All sizes listed are in stock for immediate shipment. Other lengths available. Choose from colors: Red, Blue, Yellow, Orange, Black, White, Green and Violet. One inch tubes are available at 50. t0 P„„„ ceS Ki[y to re" qn £3Wfc umecesf p„ntiW ssffi3Sssje{ " enteied «lt . t" ^ at end o£ «|w> can be art ail automatic tw „ ,,,« P0HCTW1 UorfStat'o PK1J on j„i entered f° -»« ».»'" .rina: each (* optional, Uj *t - Th e P* and M^aSggtHM '"Jl hTc^-^"™ | "is r° ffet ■ commands *»_* Jffi s ««ti» Secti S8CTI0M 2. AH OVERVIEW OF performed , take place print image printout. a cp/k compatible, s i"*™ integrated pri I iteration of prVy irectly on B" romediately, additional < resulting I display of. a t i performed dur WordStar's KDIT FUNCTION j stored on diskette. Featm following; I of the edit funct Video Editing: a portion of n, ^ always shown c^n fira^miftte" *« n 9 «t«ed or corrected i- o RAH a copy appooranc. !,,/,„ , c >','"" '" 9 '«»"" and accept witll g» aVd C S\!, 1 e 1, aVot' 1 , I 3- u ,S-fS intervention or concern. direction of printed tBXt formatting is = — ■— ••*«!= men j Key spacing, toctunac f™ ?, i^ command =^ «P after^Terau'o^ 9 ^'' Ci * M to ' i E -?h P 03 '" 11 "" to the end of o change the margins or line titled or vice versa, or to secti-- share l*** ^ ,,.( conJo^Kg-ndo « ; EKSt/M* , l i S the. oth'e. PtPM'JJt "Sfiffl , w wocdStat- -j B» •«r»e-w» d ' i 11 to "'ation atf ^"-Scte. »>dths S *SSeUnablJ»' ^uDacnP-t'^-Sv of ha.... . "*"atio ns 1 "."y-Ktio,! ..J OEft-O'T- c SU S^Sron^non-" ' Seas*; ,dd -— f , atu ^^^sas! nd utV ^ left m, Sel to „ 0rds tar ha* WoJJ as ^ e "»« than'a 5 c J n "e MicroPro Price List: Software/Manual Software/Manual Word-Star™- Word-Master TM - Tex-Writer TM - $495/40 $150/25 $ 75/15 Super-Sort I™- Super-Sort ll TM - Super-Sort III™- $250/25 $200/25 $150/25 For more information and the name of your nearest dealer, contact MicroPro International Corporation. Dealer/Distributor/O.E.M. Inquires Invited 56 BYTE September 1979 MICROPRO INTERNATIONAL CORPORATION 1299 4th Street, San Rafael, California 94901 Telephone (41 5) 457-8990 Telex 340388 HcroPro International fi': av^J mIi • ;|UK. iifiiiiiy ; ^: ^ ■>■—,,■ , .^,>ui ^ an ( ount on, no MicudPbo 1299 Fourth Street, San Rafael, California 94901 • Telephone (415) 457-8990 • Telex 340388 Programming Ouickies A Similarity Comparator for Strings T C O'Haver Professor Dept of Chemistry University of Maryland College Park MD 20742 The trouble with computers is that they have no common sense. If a computer is directed to search a file looking for a particular string of characters, a simple typographical error will cause the computer to report that no match has been found; even though there was something very close in the file. The statement "If A$ = B$ THEN. . . " is taken literally by the computer; even the slightest difference is not tolerated. Wouldn't it be better if a computer, finding no exact match, would report the best match, or the 5 best matches listed in order of closeness of match? To do this, a routine is needed that returns a quantitative estimate of the similarity between 2 strings. That is what the routine illustrated here does; it computes a similarity index on a scale of thru 100 percent. Listing 1 gives a BASIC string com- parator program. The heart of the program is in lines 100 thru 290; lines 10 thru 90 are there only to allow the routine to be demonstrated with 2 manually input strings. The funda- mental idea is simple: each character in one string is compared to each character in the other string. This is done so that groups of characters that match are weighted more heavily than the same number of matches of individual characters. This allows, for example, "POOL" and "POOR" to be rated more nearly equal than "POOL" and "POLO", even though the latter 2 strings have more characters in common. 10 LETT = 20 LETP = 3 30 PRINT "FIRST WORD" ; 40 INPUT A$ 50 LETA=LEN(A$) 60 PRINT "SECOND WORD" ; 70 INPUT B$ 75 IF A$ = B$ THEN PRINT "EXACT MATCH 80 LETB=LEN(B$) 90 IFA>B THEN LETB = A 100 FOR M = 1 TO B 110 LETC = 120 FOR I = 1 TO M 130 LETK$=MID$(A$, B-M + 1,1) 140 LETL$=MID$(B$,I,1) 150 IF K$ = L$THEN LETC=C+1 160 NEXT I 170 LETC = C!P 180 LETT = T + C 190 NEXTM 200 FOR M = B+1 TO 2*B-1 210 LET C = 220 FOR 1 = 1 T0 2*B-M 230 LETK$=MID$(A$,I,1) 240 LETL$=MID$(B$,M-B+I,1) 250 IFK$ = L$THEN LETC = C+1 260 NEXT I 270 LETC = CtP 280 LETT = T + C 290 NEXTM 300 LETS=100*T/BtP 310 PRINT S;"%" 320 LETT = 330 GOTO 70 340 END Listing 1: Listing of the similarity comparator program in Ohio Scientific Instruments 8 K BASIC (a Microsoft interpreter). The up arrow indicates exponentiation. 58 September 1979 © BYTE Publications Inc What makes the Microtek Printer so different? Nothing! EXCEPT. . . . THE PRICE: $750 (with parallel interface) THE PERFORMANCE: • 80 or 1 20 columns (software selectable) • Plain paper • Pin Feed • Double width printing • 1 25 characters per second, 70 lines per minute nominal throughput • 9x7 Matrix (80 columns/line), 7x7 Matrix (1 20 columns/line) • Vertical Format Unit • 96-character ASCII (upper and lower case) • Forms width continuously adjustable between 4.5 inches and 9.5 inches (including sprocket margins) • Parallel (Centronics type) interface standard. Serial (RS-232) and IEEE-488 interfaces available To: MICROTEK, Inc., 7844 Convoy Court, San Diego, California 921 1 1 □ Send me more information. (714) 278-0633 □ Send me a printer with: □ Parallel interface 100% because of double letter 3 letter pattern "POO" matches. Still a 3 letter pattern. Same match, because nonmatching characters do not count. Two 2 letter matches, "PO" and "OL", do not count as much as one 3 letter match. Only 2 isolated letters. Presence of extra random character reduces match. Repeated letters result in unexpectedly high match. Listing 2: A sample run of the program, with comments explaining the value of similar- ity assigned. Note: We entered this program into an Apple II computer using the Applesoft floating point BASIC. It ran without modification. The exact values of similarity computed did sometimes differ from those given in the sample run, but only in the fourth significant digit and beyond . . . RSS E, ■o KIM ANALOG INPUT Analog to Digital Conversion System for the KIM Computer Give trie KIM Ute ability Co sense? n«asurer and control tne world around it witb DWI SYSTEMS modules. Just plus tne KIMSET1 into the KIM to set 16 channels of analoa input. Screw terminals are provided for each channel so you can hooK up Joysticks* pots* or whatever approF-riate sensors you have. Each of the 16 analoS inputs* in the ranse of O to 5.12 volts* is conver ted to a decimal number between snd 255 < 20 millivolts per count). Conversion time is 100 microsconds. The K1MMOD provides one user port as well as a HAM SYSTEMS port. Software is provided. • TEUFERATURE • VELOCITY • PRESSURE -ACCELERATION I- AIM 161 1-KIMM0D t- CABLE A24 1-MANM0D1 1-P0W1 KIM SET! 16 ANALOG INPUTS ■ B BETS I00MICROSEC I INTERCONNECT CABLE - POWER MODULE 3 [ for 110 VAC $ 285 for 230 VAC $295 CONNECTICUT microCOMPUTER , Inc. 750 POCONO ROAD BROOKFIELD, CONNECTICUT 06804 TEL: (203) 775-9659 TWX: TLX: 7104560052 VISA AND M/C ACCEPTED - SEND ACCOUNT NUMBER, EXPIRATION DATE AND SIGN ORDER. ADD 13 PER ORDER FOR SHIPPING ft HANDLING - FOREIGN ORDERS ADD 10% FOR AIR POSTAGE 60 September 1979 © BYTE Publications Inc Circle 76 on inquiry card. Unclassified Ads Unclassified Policy Readers who are soliciting or giving ad- vice, or who have equipment to buy, sell or swap should send in a clearly typed notice to that effect. To be considered for publi- cation, an advertisement must be clearly noncommercial, typed double spaced on plain white paper, contain 75 words or less, and include complete name and address information. These notices are free of charge and will be printed one time only on a space available basis. Notices can be accepted from individuals or bona fide computer users clubs only. We can engage in no correspondence on these and your confir- mation of placement is appearance in an issue of BYTE. Please note that it may take three or four months for an ad to appear in the magazine. FOR SALE: Cromemco 16 K programmable memory. 4 MHz. bank select. $400 cr best offer. Will Aokel, 4860 Rolan- do CI #22. San Diego CA 92115, (714)287-6823. EXCHANGE IDEAS: I want to talk and write to microcom- puter users who are interested in programming for farm operations, especially in the area of Southwest Kansas, Southeastern Colorado and the Oklahoma Panhandle. I am using an Apple II. Van Lynn Floyd, RR #1 POB 94, Johnson KS 67855. FOR SALE: OSI 65 V system, including: 6502 processor board. 16 K memory board; video interface board; power supply and case. SwTPC keyboard; single drive lloppy disk, floppy disk interface board; lloppy disk power supply and case; all documentation (OSI and fvlOS technology); includes BASIC. Assembler, Disassembler and extended monitor. All assembled, tested and running well. $1800 or best offer. C Gum, 757 E Main St W-304 Wiss Apt. Lansdale PA 19446. (215)855-4182. WANTED: Programs (games, graphics or just unusual pro- grams) in BASIC. Hope to establish a no cost program library in the near future. All material written or cassette (cassettes in TRS-80 Level 2 only) returned. Richard G Ginder, 509 Southern Hills Dr, Hot Springs AR 71901. FOR SALE: SOL-20 computer by Processor Technology with 32 K. video display, cassette mass storage, Extended BASIC, IBM Seleclric lypewriter/printer, text editing and other soft- ware, complete documentation and manuals. Ideal for small business software development, 1.5 years old, $2500. Middleton Associates. 980 Yonge St Ste 404. Toronto Ontario. CANADA M4W 2J9. (416) 961-5136. FOR SALE: S-100 bus system. Cromemco Z80 processor. Byte-8 mainframe, TDL system monitor board, ACT-I keyboard, North Star disk and software, two 16 K static pro- grammable memory (250 ns). less 8 K of chips. Panasonic video monitor. Up. tested and running. For more details of system, send SASE or phone (206) 456-2466 after 5 PM. Donald A Coulter, 8002 Mountain-Aire Loop SE, Olympia WA 98503. FOR SALE: Sencore Model PS163 dual trace scope in new condition. Used less than 20 hours. Complete with two probes. Faclory price $895, will offer for $350. Also, Sencore Model PS148 single trace scope/vectorscope, still in faclory carton Sacrifice, $195. R Conde. 11 Sugarbush Ln. Coram NY 11727, (516)928-4849. FOR SALE: Digital Group TVC64 16 line 64 character upper and lower case and Greek with plug $125; COSMAC ELF with complete address light emitting diodes, hexadecimal thumb- wheels, audio output, automatic stepping and other features $110; hexadecimal keyboard for ELF $30; Mikos mother board with 12 100 pin connectors in place $75; Proko PTR-II optical paper tape reader $50. Bert Thiel.159 W Main St, Frostburg MD 21532, (301) 689-8608 weekends and even- ings. ■ Circle 335 on inquiry card. Whynol kill two birds with one stone? If you have an Apple* and you want to interface it with parallel and serial devices, we have a board for you that will do both. It's the AIO.™ Serial Interface. The RS-232 standard assures maximum compat- ibility with a variety of serial devices. For ex- ample, with the AIO you can connect your Apple* to a video terminal to get 80 characters per line instead of 40, a modem to use time-sharing services, or a printer for hard copy. The serial interface is software programmable, features three handshaking lines, and includes a rotary switch to select from 7 standard baud rates. On-board firm- ware provides a powerful driver routine so you won't need to write any software to utilize the interface. Parallel Interface. This interface can be used to connect your Apple* to a variety of parallel printers. The programmable I/O ports have enough lines to handle two printers simultaneously with handshaking control. The users manual includes a software listing for controlling parallel printers or, if you prefer, a par- allel driver routine is available in firm- ware as an option. And printing is only one application for this general purpose parallel interface. Two boards in one. The AIO is the only board on the market that can interface the Apple to both serial and parallel devices. It can even do both at the same time. That's the kind of innovative design and solid value that's been going into SSM products since the beginning of personal computing. The price, including PROMs and cables, is $135 in kit form, or S175 assembled and tested. See the AIO at your local computer store or contact us for more information. 2116 Walsh Avenue Santa Clara, California 95050 (408)246-2707 'Apple is a TM of Apple Computers, Inc. Some Musings on Hardware Design Clayton Ellis Rt 4, POB 86 Montrose PA 18801 The purpose of this article is to acquaint the reader with some of the more interesting types of transistor-transistor logic (TTL) integrated circuits, the ease with which logic design can be accomplished, and to offer a few design considerations and trouble- shooting hints to stimulate the homebrew use of digital logic. Taking the topics in the above order, we start with a look at some of the more com- plex types of TTL chips in the "74xx" series. (We will ignore simple gates for the most part.) An example is the 7442. This integrated circuit is a binary coded decimal (sometimes called BCD) to decimal decoder. What this means is that the circuit will decode 1 line out of 10 based on a 4 bit binary code. Figure 1 shows the pin con- nections. Regardless of what it is called, it works like this: pins 12 thru 15 are a 4 bit binary input, pin 1 5 being the 1 's bit (bit 0), 14 the 2's bit (bit 1), 13 the 4's bit (bit 2), and 1 2 the 8's bit (bit 3). Pins 1 thru 7 and 9 thru 11 comprise the output pins, each pin staying high (logic 1 or a higher level voltage of about 3 to 5 V) unless the corresponding binary code is applied to the input. For example, let's say that pins 12 thru 15 are 0101. In other words, 12 is at a logical low (about V); 13 is at a logical high level ► 5V A 16 Vcc O 1 2 l 15 A 7442 2 3 14 B 3 4 4 5 5 6 13 C 6 7 7 8 9 9 12 D 10 1 1 GND a (above about 3 V, less than 5 V), etc. In this case, pin 6 (indicating a decimal 5) would be at a logical low level (about V). All other pins relating to decimal output numbers would be at a logical high level. Note that only one output pin will be low at any given time, corresponding to the binary value of the input lines. "Ahh," you might ask, "what if the input pins are at some binary value other than thru 91" The answer is easy; this constitutes an invalid input, and all output pins will stay high. Only valid deci- mal values will select an output pin. Now let's move on to a module similar to the 7442, the 74154. Referring to figure 2, the first apparent difference is the larger number of pins on the 74154. This inte- grated circuit is a 4 line to 16 line decoder. Its operation is the same as the 7442, with but two exceptions: there are now 16 valid output lines, and provision is made to allow 24 ADDRESS LINES 23 22 GATE INPUTS \ 19 Vcc A 74154 O 1 2 2 3 8 3 4 4 5 C 5 6 6 _7 D 7 8 8 9 9 IP 10 II 1 1 13 12 14 Gl 13 15 G2 14 16 GND 15 17 12 n 7 \0UTPUTS Figure J: Pin connections for a 7442 TTL binary coded decimal to decimal converter. Figure 2: Pin connections for a 74154 TTL 4 line to 16 line decoder. 62 September 1979 © BYTE Publications Inc DATA ' SELECT STROBE Figure 3: Pin connections for a 74750 TTL 1 of 16 line data selector. two extra inputs to gate the individual line selected. Pins 18 and 19 perform this gating function. An example of use of this extra gating feature might look like this: pins 20 thru 23 might contain the binary equivalent of a decimal 14, pin 19 being low and pin 18 alternating from high to low (a periodic clock pulse.) The end result is that pin 16 (corresponding to line 14) will also periodi- cally alternate high and low in following the signal on pin 1 8. The data at pin 18 is trans- ferred to pin 14. If the binary code on pins 20 thru 23 were now changed to a decimal 7, then line 7 (pin 8) would follow the data on pin 18. We select one of 16 outputs for a signal applied to the gates. Now, if we could just have a binary controlled switch to select 1 of 16 inputs. Let's look at the 74150. Figure 3 shows the pinout of this one. This time there are 21 input pins and only 1 output pin. Let's see how this one works. Binary input is on the 4 lines of pins 1 1 and 1 3 thru 15. Let's say a binary value of 12 is present. This selects the number 12 input line (pin 19) and transfers the level of this line, be it steady, high, low or some alternating clock signal, to pin 10, the output line. Notice, though, that in order for the data to be transferred, pin 9 (the strobe input) also must be low. A high level on the strobe input prevents any data transfer from any input. This feature is used to allow data transfer only at selected intervals, such as The way you check line-by-line with an A P Intra-Switch or Intra-Connector. You plug your Intra-Switch in-line with standard socket connectors, and instantly you've got a separate, independent on-off switch for each and every line in your flat ribbon cable. To switch, you nudge with a pencil point. It's that quick. Imagine how much time and trouble Intra-Switch will save you in your diagnostic and quality testing, your programming and selective line inhibiting. Or, plug in your Intra-Connector (see box) the same way, and you have an extra set of male contacts at right angles. Instant line-by-line probeability— and an easy way to tap your system and daisy chain it into new areas. Both Intra-Connectors and Intra- Switches come in 20, 26, 34, 40 and 50-contact models. Where? At your nearby A P deal- er. Where's that? Phone (toll-free) 800-321-9668. And ask for the com- plete A P catalog, The Faster and Easier Book. AP PRODUCTS INCORPORATED Box 110D • 72 Corwin Drive Painesville, Ohio 44077 Tel. 216/354-2101 TWX: 810-425-2250 Faster and Easier is what we're all about. Circle 10 on inquiry card. September 1979 © BYTE Publications Inc 63 CDMPHCT COMPILER FORMS GENERATOR 5TRNDRRD COMPILER FOR FAST IMPLEMENTATION OF BUSINESS APPLICATIONS Compact Compiler requires only 20K bytes. Our compact Version 3 Compiler requires only 20K bytes but supports a powerful subset of standard COBOL plus the CIS COBOL language exten- sions for conversational mode working, providing full CRT screen formatting with built-in cursor control and numeric field validation. Other features include CIS COBOL Indexed Sequential and Interactive Debug packages, linkage to run time sub- routines to CHAIN programs together, PEEK & POKE memory locations and GET & PUT to special peripherals. Forms Generator speeds program devel- opment. Forms is a powerful utility which can be used with either the Stan- dard or Compact COBOL Compiler. Forms generates record descriptions for Data Entry and Enquiry Programs. The operator creates and edits the re- quired data entry form on the CRT by means of a question and answer session, and then automatically creates the required COBOL source text. This text is held on diskette as COPY files which the programmer can then simply COPY into his program in the normal COBOL way. Standard Compiler conforms to ANSI 74 Specifications. And now our ANSI 74 standard Version 4 Compiler imple- ments level 1 of Nucleus, Table Handl- ing, Sequential I/O, Relative I/O, Indexed I/O, Library, Segmentation and Inter Program Communication plus many level 2 features and the CIS COBOL language extensions employed in Version 3. This compiler runs in 30K bytes and is ideal for implementing or converting large systems using modular programming. Features include dynamic program loading and fast program devel- opment turnround. CIS COBOL products run on the 8080 or Z80 microprocessors under the CP/M operating system. They are distributed on a variety of diskette formats and have a CONFIG utilility supplied as standard, which enables you to drive many different types of CRT. All are themselves written in CIS COBOL and are therefore readily transferred to different operating environments including new operating systems and new microprocessors, making CIS COBOL a very attractive proposition for OEMs. MICRO FOCUS MICRO FOCUS LTD. 58 Acacia Rd, St. Johns Wood, London NWB 6AG Telephone: 01-722 8843 Telex: 28536 MICROF G •CP/M is a trademark ot Digital Research 64 BYTE September 1979 Circle 210 on inquiry card. Figure 4: A data selector to sample each of 16 lines sequentially. It looks good, but it doesn't work. A neglected inversion in logic levels and thinking is the demon. I 2 3 4 5 6 7 8 9 10 II 12 13 14 15 74154 Vcc A B C D GND o- 23 12 22 21 20 12 ► 5V rh + 5V Figure 5: Another approach to the problem in figure 4. This approach has a much lower parts count, so it is much easier to wire and it works. 0A QB QC B 7493A A(CLOCK) „ QD Vcc m when the input would contain valid data, or when the output is useful only at specific intervals. Now that we have taken a look at a few of the more involved logic blocks, let's look at how easy it is to design the somewhat more complicated circuits using the simple TTL blocks in conjunction with one or more of the above type of logic blocks. If we want to build a sequencing device to look at a number of incoming lines, and if we are to use a given clock signal to coor- dinate all this, we can use the logic circuit in figure 4. A very simple and straight- forward circuit, right? Not quite. Let's take a second look. All the inputs but the one selected by the 74154 are going to be en- abled at one time. The selected pin goes low, remember? By this time, if not before, you probably recalled the look we just took at the 74150 and are wondering why we did not use it. Figure 5 shows the circuit using the 74150. The foregoing just illustrates a good point (and one to keep in mind when- ever you undertake any logic design). There o- o- O- O- O- o- o- Vcc 74I50 OUT C^ -o 1 OA QB 0C 0D B V 749 3 A A(CLOCK) Rl R2 GND September 1979 © BYTE Publications lnc 65 Get circuit requirements down on paper in block form. Break each block down into required logic. Use the most integrated block available for each function as in the example of figure 5 unless the cost of such a module is much higher than two or possibly three less intricate ones. Don't go overboard with smaller blocks. This increases the density and complexity of interconnection, greatly increases the chances of errors and reduces system reliability. Cross-check all designs, as you may have redundantly developed the same signal line. Sometimes most of one segment of a circuit can be eliminated with an inver- ter or small amount of additional gating. If possible, have a friend familiar with digital logic go over the layout. Your friend can sometimes suggest circuit reductions that you missed simply because you were thinking one way while your friend used a different approach. The same review may even spot an error in the logic. With all those inversions, gating, etc, it is easy to do. Spotting an error at this stage can save hours at the breadboard stage. Table 1: Approach to finding the simplest logic circuit for a given function. are many ways to accomplish a specific func- tion. So many, in fact, that large companies who do digital logic design in large quantities invariably use some form of computer aided logic design. The homebrew enthusiast ob- viously can't go that far, but the approach summarized in table 1 usually works fairly well. Timing Another good point to keep in mind is to think time (not in terms of how long it takes to design a circuit, or build it, but time rela- tionships in the circuitry itself). This brings us back to a term, clock, that we have been using freely up to now. We all know that a clock is merely a line, usually derived from a square wave oscillator, right? This line is then used to coordinate all necessary gating, shifting, setting and resetting, etc, that goes on within the circuitry itself, right? Well, that is part of it, but who said it had to be a single line? Some computers use a number of clock lines, perhaps as many as 8 or 10. The only thing these multiple clock lines have in common is that they are usually all derived from the same oscillator and may be individually gated on or off, counted, decoded or subjected to any other valid logic manipulation. Figure 6 shows a typical clock circuit detailing some of these practices. As you can readily see, almost any combination of clock times can be selected, and the flip flops can be extended as far as needed to select a single clock pulse or a repetitive series of clock pulses. The point to remem- ber is that all pulses are derived from the same clock and each pulse on any line will be of the same duration as any other clock pulse. The single clock pulse shown on line C of the timing chart in figure 6 will start at the same time as the fourth clock TOGGLE FLIP FLOPS DIVIDE FREQUENCY BY 2 Figure 6: A hypothetical clock circuit to give two different phases (lines A and B) at two different repetition rates. Lines A and B are at 1 j2 the clock rate. Line C is at 1/8 the clock rate with the same pulse duration. -^>c— [u>c- T Q FF I T FF2 {> T Q FF3 T FF4 ^>A Ob ^y -Oc CLOCK ~L ~L ~L r n CLOCK* FFI _TL CLOCK.FFI CLOCK'FFI • FF2 "FF3 66 September 1979 © BYTE Publications Inc pulse on line A, and the duration will be identical. There is one fly in the ointment at this point. I just noted that the two clock pulses would start at the exact same time. That is not quite true, however, and depending on how fast the clock is running, and exactly what is being gated, this may or may not be a problem. In an actual circuit, the clock pulse on line A would go positive slightly ahead of the pulse on line C. This is due to the delay (called propagation delay) across each flip flop encountered by the leading edge of the pulse. This delay is on the order of nano- seconds for each gate encountered. Let us assume an arbitrary 5 ns delay for each gate. Then the delay from the input of FF1 to the output of the AND gate driving line A would be 10 ns. This is 5 ns for FF1 and 5 ns for the AND gate. The delay from the input to FF1 to the output of the AND gate driving line C would be not 10 ns, but 20 ns: 5 ns for each of the three flip flops and 5 ns for the AND gate. The pulse on line C would actually start 10 ns after the one of line A. This will also make a difference in the dura- tion of the pulse on each line; as the plus level arriving later than the clock pulse at the input to the AND gate determines when the output of the AND gate goes positive. However, the trailing edge of the clock pulse input determines when the AND gate output goes negative. This, in effect, shortens the duration of the pulse on the output line by a time (in nanoseconds) determined by the various propagation delays. If the clock frequency of the circuit is on the order of tens or hun- dreds of kilohertz, then a delay of tens of nanoseconds would be of little consequence; but if the clock frequency of the circuit is something like 20 or 25 MHz, the delay can become a thorn in the side of the designer. This holds true for all data and control lines we well as clock lines. This propagation delay can be used to an advantage too. Figure 7 illustrates using this delay to generate a narrow pulse. Here the positive going (leading) edge of the input is applied to an AND gate, but the negative going (trailing) edge of the inverted version applied to the other leg of the AND gate is delayed by the total of the propagation delay across the three inverter blocks. The resultant output is a narrow pulse equal in duration to the delay across the inverters. This method of generating a pulse is only useful in cases where we don't care exactly how long the pulse lasts since gates and inverters are subject to manufacturing variations. To satisfy the rather picky individual or very high speed circuit, I have to say also that the output pulse is not only derived from the inverter delay, but is delayed from the leading edge of the original pulse by the amount of the delay across the AND gate itself. Figure 8 illustrates this. The short de- lays shown on waveform C are due to the AND gate propagation delay. For most situa- tions, this is carrying propagation delay accounting to extremes, but in certain high speed circuits each delay may have to be accounted for. If 20 or 30 gates are involved, the cumulative effects add up rather fast. Also to be considered is the capacitive effect of the interconnection lines: the dis- tributed and stray capacitance which are in parallel with the output of each gate add slightly to delay times. It takes a finite amount of time to charge this capacitance at Figure 7: A pulse generator for nanosecond range pulses. Pulse length Is determined by the propagation time through the gates between the input and point B. More sophis- ticated methods are required if an accurate pulse length is required. Figure 8: A magnified view of the pulse shown in figure 7. The output pulse is de- layed by the propagation time of the A ND gate. This time varies but is typically about 10 ns for normal transistor-transistor logic, less for the high speed and Schottky version and more for the low power integrated circuits. September 1979 © BYTE Publications Inc 67 each gate turn on, and the gate will not switch until a certain voltage input level is reached. All of which leads right into the last subject I'd like to touch on. How do you see all this in an actual circuit? Believe me when I say that it takes a good oscilloscope. To have a good display in the tens of nano- seconds range, it takes an oscilloscope with a bandwidth of at least 60 to 100 MHz. Does this mean that anyone without such an oscilloscope can't do much with higher speed TTL? Not necessarily. Remember we said that propagation delay only becomes a problem at high speeds and multiple gate delays. There are a number of ways around this. One is to keep clock frequencies and data changes as slow as possible. Don't use a fast clock or data encoding just for the sake of speed, run it as fast as necessary and no faster. If you can tolerate a slow clock speed, use it. Another method is to try and bring each data line that is to be gated with another line through the same number of gates as the line it is to be gated with. In other words, if one line originates at about the same source as another that it is to be gated with, but passes through 9 levels of gating, and the other line passes through 3, the delays at high speeds can be a problem. This could be compensated for by changing the way the lines are gated to bring the delays in each line closer to the ■o o U "D c (0 Q. £ o u CT> say computer say PET winner ITM say special : $100.00 of Commodore programs FREE if PET is purchased from ComputerLand by October 31, 1979. > c? You do more than just follow the crowd. You're a trend setter. You're a winner. Getting into your own computer is your next move. 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ComputerLand ■ WE KNOW SMALL COMPUTERS 68 September 1979 © BYTE Publications Inc Circle 75 on inquiry card. same length. Another help in extreme cases is to run the line with the lesser number of gates through several pairs of inverters. This introduces a delay to compensate for the delay in the other line. In other words, make the faster line wait for the slower one. An even better solution is to design your circuits "synchronously" so that only one clock source ever changes the state of a flip flop or memory cell. As to seeing these problems on the slower oscilloscopes, there are several hints that will help. Very little serious work with timing relationships can be undertaken without a dual trace capability (although a good deal can be done otherwise with TTL with just a single trace scope). Even with a dual trace oscilloscope, the fastest sweep speed may not reveal a lot of timing detail if not set up correctly and the alternate sweeps may not be time correlated without a common syn- chronization signal. A number of tests can be made with a single trace oscilloscope if it has provisions for external synchronization. In general, synchronize the oscilloscope sweep as far ahead in time as is realistic for the signals in question, in order to allow time for the sweep to start before the pulse actually arrives. It goes without saying that the synchronization signal must be common to all signals being examined. If you still can't see any difference, try estimating the approximate delay for each line from source to common logic block. Most logic handbooks list typical delays for integrated circuits. If the problem is in a counter circuit of some type which counts "up," the count for a given sequence will usually be too high in value if delay prob- lems are the cause. Rarely will the count of an "up" counter be too low, as the usual situation is advancing the counter by an ex- tra pulse generated by mismatched delays, especially if a lot of exclusive ORing is being done. The situation where early turn off or disabling of the counter causes a missed count is quite unlikely, mainly because the delay is of a much shorter duration than the pulses being counted. These problems are all good to be aware of, but don't let them deter you from start- ing that project you were thinking about. You may go a long time before you see one of the problems described. Don't let the lack of a superb oscilloscope deter you either. A lot of very intricate and fast digi- tal circuitry is being built every day with nothing more than a single trace I MHz AC coupled oscilloscope. With a little experi- ence, you can tell a great deal about a given TTL circuit with one of these inexpensive oscilloscopes." 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September 1979 © BYTE Publications Inc 69 A Low-Speed Analog-to-Digital Converter for the Apple II Richard C Hallgren Assistant Professor Michigan State University College of Osteopathic Medicine, Dept of Biomechanics East Lansing MI 48824 The development of micropro- cessor-based computer systems has progressed to the point where it is now practical to utilize these systems in a scientific or laboratory applica- tion. To be useful in a scientific appli- cation the computer must have the capability o/ converting analog signals to digital signals. Very few home computers have this capability. Certainly it is a straightforward task to design an analog-to-digital con- verter (ADC), but the real problem lies in connecting the converter to the computer. The Apple II computer, with 8 peripheral-board connectors on the mother board, makes the job of designing and implementing special interfaces (such as the ADC) rela- tively easy. The peripheral-board connectors give the hardware designer access to all address, data, and control lines. In addition all con- trol, address, and data lines have been buffered, and certain address bits have been decoded to give a device select (DS) signal. What this means is that when a specific range of address locations is accessed, the DS line will give a low output signal. Since the peripheral-board connectors are on the main computer About the Author Richard Hallgren is an Assistant Professor in the Dept of Biomechanics at Michigan State University. He is working on the application of microprocessor-based systems in scientific research. IC1 MC 14028 16 a IC2 MC14049 1 B IC3 SN7427 14 7 IC4 MC14013 14 7 IC5 MC14433 24 13 IC6 AD580 — — IC7 MC14503 16 8 IC8 MC14503 16 a IC9 DM7432 14 7 Number Type +5V GND -5V 12 Table 1: Voltages which must be supplied to integrated circuits in figure 1 for operating power. board, the finished interface board will be inside the computer and will be able to use the computer's power supply. Because of these character- istics, turning the Apple II into a real- time data analyzer becomes a matter of designing an analog-to-digital con- verter circuit, and control logic to meet the need of the application. Many of the applications that I had in mind were to be of a low-speed nature (eg: monitoring the tempera- ture of experimental animals in medical physiology laboratories, analyzing the results of elec- trophoretic analysis). Therefore, a low-speed analog-to-digital converter built around the Motorola MC14433 integrated circuit seemed to be a cost effective approach. I was inspired by Steve Ciarcia's article, "On a Test Equipment Diet? Try an 8 Channel DVM Cocktail!" (December 1977 BYTE, page 76). The left section of figure 1 shows the analog-to-digital converter cir- cuitry. All data and status lines to the computer are isolated through the MC14503 3-state buffers (IC7 and IC8). The MC14433 (IC5) is allowed to convert continuously at a rate of approximately 15 conversions per second. This means that if the data transfer to memory starts immedi- ately after the conversion ends, the Apple II can easily decode and store the data from one conversion before another conversion occurs. IC4, con- figured as an RS flip-flop that is in- itially reset by the computer, is set by the MC14433 after an analog-to- digital conversion has been com- pleted. When the computer senses this change in status, it starts the decoding and data transfer process. IC6 is an AD 580 used to provide a stable reference voltage to the MC14433. The right section of figure 1 shows the control logic that is necessary to coordinate the transfer of data to the computer, and control signals from the computer. The circuit is designed so that the peripheral card resides in I/O (input/output) slot 7 on the Apple II mother board. The device select signal will go low whenever hexadecimal memory locations C0F0 thru COFF are addressed. The least Text continued on page 74 Figure 1: Schematic diagram of analog-to- digital-conversion circuit and associated control-logic circuitry. The analog-to- digital (A/D) converter is shown on the left side, the control logic on the right side . »_ 70 September 1979 © BYTE Publications Inc ANALOG-TO-DIGITAL CONVERSION CIRCUIT ^ — | 0-1.999 ■^ 1 VOLTS D7 D6 D5 04 D3 D2 Dl DO R/W DS September 1979 © BYTE Publications lnc 71 Circle 379 on inquiry card. U.S. ROBOTICS, INC. 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CHICAGO, ILL. 6D607 Sales (312)733-0497 General Offices (3 1 2) 733-0498 Service (312)733-0499 ( CALL FROM "\ V ^ BASIC ROUTINE^ / SAVE A,X, AND Y REGISTERS INITIALIZE DATA STORAGE LOCATION YES (RETURN TO ^ BASIC ROUTINE J INPUT DIGIT CODE AND DIGIT YES STORE DIGIT YES Figure 2: Flowchart of the machine language subroutine which takes samples from the analog-to-digital converter. This code is written for the 6502 processor used in the Apple II. 72 September 1979 © BYTE Publications Inc CENTRONICS DELIVERS THE WORD ON COMPUTER PRINTERS. To get the most from a computer system, you need a permanent wfi t ten record — information that you can use for reports, correspondence, or just about anything. For that, Centronics printers deliver the word. From top left, clockwise: Model 700 Impact printer, 60 cps, 132 column format. Model 779 Impact printer, 60 cps, economical forms handling. Model 701 Impact printer, 60 cps, bidirectional, 132 column format. 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BYTE September 1979 73 Address Instruction Op Code Operand Comments 4000 4003 4006 4009 400A 400C 400E 4010 4012 4014 4016 4019 401 B 401 E 401 F 4022 4024 4026 4029 402C 402F 4030 4031 4032 4033 4036 4D37 4038 4039 403A 403B 403C 403D 403E 403 F 4040 4043 4046 4048 404A 404C 404F 4052 4054 4056 4058 405B 405 D 405F 4061 4062 4064 4066 4068 4069 406B 406E 4071 4073 4075 4077 407A 407C 407E 4080 4081 4083 4085 4087 4088 408A 408D 4090 4092 4094 4096 4099 409B 409D 409 F 40A0 AD B0 8E B1 8C B2 08 A2 00 A9 00 85 0A A9 4A 85 0B A9 00 8D A0 A9 4E 8D A1 78 AD A1 C5 OB DO OB AD BO AE B1 AC B2 28 60 58 EA 4C 1E EA EA EA EA EA EA EA EA EA EA 8D F2 AD F1 29 80 C9 80 DO F7 AD FO 8D A2 29 80 C9 80 DO F4 AD A2 29 OF 81 OA A4 OA C8 84 OA DO 05 A4 OB C8 84 OB AD FO 8D A2 29 40 C9 40 DO F4 AD A2 29 OF 81 OA A4 OA C8 84 OA DO 05 A4 OB C8 84 OB AD FO 8D A2 29 20 C9 20 DO F4 AD A2 29 OF 81 OA A4 OA C8 84 OA 49 LDA 49 STX 49 STY PHP LDX LDA STA LDA STA LDA 49 STA LDA 49 STA SEI 49 LDA CMP BNE 49 LDA 49 LDX 49 LDY PLP RTS CLI NOP 40 JMP NOP NOP NOP NOP NOP NOP NOP NOP NOP NOP CO STA CO LDA AND CMP BNE CO LDA 49 STA AND CMP BNE 49 LDA AND STA LDY INY STY BNE LDY INY STY CO LDA 49 STA AND CMP BNE 49 LDA AND STA LDY INY STY BNE LDY INY STY CO LDA 49 STA AND CMP BNE 49 LDA AND STA LDY INY STY $49 BO $49B1 Save registers $49B2 #$00 #$00 $0A Starting location of data storage #$4A $0B #$00 $49A0 Final location of data storage #$4E $49A1 Disable interrupt $49A1 $0B $4031 Have all data locations been filled? $49B0 $49B1 $49B2 $401 E $C0F2 $C0F1 #$80 #$80 $4043 $C0F0 $49A2 #$80 $0A $0A $406B $0B $0B $C0F0 $49A2 #$40 #$40 $406B $49A2 #$0F ($0A,X) $0A $0A $408A $0B $0B $C0F0 $49A2 #$20 #$20 $408A $49A2 #$0F ($0A,X) $0A $0A Enable Interrupt Start A/D conversion A/D conversion finished? Input data Temporary data storage #$80 Check for first digit (MSD) $404C $49A2 #$0F ($0A,X) Peel off digit code leaving data Store data Increment lower 8 bits of data storage Carry out to upper 8 bits? Increment upper 8 bits of data storage Input data Check for second digit Peel off digit code leaving data Store data Increment lower 8 bits of data storage Carry out to upper 8 bits? Increment upper 8 bits of data storage Input data Check for third digit Peel off digit code leaving data Store data Increment lower 8 bits of data storage Listing 1: The machine language subroutine for collecting data from the analog-to-digital converter, here shown in assembly language format. Memory loca- tions 03FE and 03FF contain the hex- adecimal interrupt jump vector 4040, which is the entry point of this routine. Text continued from page 70: significant 4 bits of the address are decoded by ICl and are used for on board addressing. Performing a store accumulator (STA) operation to loca- tion C0F2 causes the SC (start conver- sion) line to go high and resets the flip-flop IC4. Performing a LDA (load accumulator) from hexadecimal location C0F1 transfers the end of conversion (EOC) and overrange (OR) status data into the computer. Performing a LDA from location C0F0 transfers the digit-select code and the binary coded decimal (BCD) value of the particular digit selected into the computer. The software portion of the analog- to-digital converter project is divided into 2 parts: • A machine language routine to provide high-speed transfer of data from the MC14433 to the computer memory. • A BASIC routine written in Applesoft floating-point BASIC to take the data in memory and for- mat it into a voltage that can be displayed as a function of time with the high-resolution graphics routine. Since the Apple II does not have an internal real-time clock, I decided to use the interrupt request line (IRQ) as an input for an external clock. The advantage to this is that a calibrated pulse generator can be used to deter- mine the sampling rate. If desired, the computer can perform other tasks between samples. Knowing when each sample was taken makes it possi- ble to display the data as a function of time with the high-resolution graphics routine. Since the Apple II high-resolution graphics allows the display of 256 points I decided to store 256 points in memory before displaying the data, but there is no reason why the data could not be displayed as it is taken. Figure 2 shows the flowchart of the machine language program, and listing 1 74 September 1979 © BYTE Publications Inc 6809! S-100 Compatibility.6809 Computability. 6809 16 bit internal arithmetic Hardware multiplication Two stack pointers Two index registers 18 addressing modes Fully relocatable code Five interrupts Up to three times the throughput of a 4MHz Z-80 • 1K RAM • 10K PROM space • MONBUG II monitor included • 2400 baud cassette interface • 20 I/O lines • RS-232 level shifters • Real time clock • DMA • Parallel keyboard input • Memory-mapped video output • Fully S-100 compatible (including 8080 type I/O) • A complete system, ready to use. MD-690a Single Board Computer $239 kit $299 assembled 6802 Processor also available Ask about 6802, 6809 and Z80 systems. Please rush the following: D CPU Card (kit) □ CPU Card (assembled) Name Address Company City State/Zip MicroDaSys P.O. Box 36051 Los Angeles, CA 90036 (213)935-4555 CA residents add 6%. Visa and Mastercharge accepted. Circle 221 on inquiry card. BYTE September 1979 75 Carry out to upper 8 bits? Increment upper 8 bits of data storage Input data Check for LSD (least significant digit) Peel off digit code leaving data Store data Increment lower 8 bits of data storage Carry out to upper 8 bits? Increment upper 8 bits of data storage Return from interrupt Listing 2: Program in Applesoft floating point BASIC which calls the machine language routine of listing 1 and then formats and displays the data received, using the high- resolution graphics capability of the Apple II. 40A2 DO 05 BNE $40A9 40A4 A4 OB LDY SOB 40A6 C8 INY 40A7 84 OB STY SOB 40A9 AD F0 CO LDA SCOFO 40AC 8D A2 49 STA S49A2 40AF 29 10 AND #$10 40B1 C9 10 CMP #$10 40B3 DO F4 BNE $40A9 40B5 AD A2 49 LDA S49A2 40B8 29 OF AND #$0F 40BA 81 0A STA ($0A,X) 40BC A4 0A LDY $0A 40BE C8 INY 40BF 84 0A STY $0A 40C1 DO 05 BNE $40C8 40C3 A4 0B LDY $0B 40C5 C8 INY 40C6 84 OB STY SOB 40C8 A5 45 LDA $45 40CA 40 RTI Program 100 DIM Z (300) 101 HOME 102 GOTO 1000 110 CALL 16384 1 1 1 HOME : VTAB 24 112 PRINT "THE DIGITIZED DATA IS BEING FORMATTED FOR PLOT ING" 113 X= 18944 115 FORJ = 0TO255 120 V1 = PEEK(X) 122 V2=PEEK(X + 1) 124 V3=PEEK(X + 2) 126 V4 = PEEK(X + 3) 128 X = X + 4 130 IF V1 > 7 THEN V1 = 132 IF V1 = OTHEN GOTO 140 134 V1 = 1 140 V$ = STR$ (V1) + STR$ (V2) + STR$ (V3) + STR$ (V4) 150 Z(J) = VAL(V$)/1000 160 NEXT J 200 HGR: HCOLOR = 3 202 HPLOT 20,0 TO 20,150 204 HPLOT TO 279,150 208 HPLOT 18,0 TO 22,0 210 HPLOT 18,10 TO 22,10 212 HPLOT 18,20 TO 22,20 214 HPLOT 18,30 TO 22,30 216 HPLOT 18,40 TO 22,40 218 HPLOT 18,50 TO 22,50 220 HPLOT 18,60 TO 22,60 222 HPLOT 18,70 TO 22,70 224 HPLOT 18,80 TO 22,80 226 HPLOT 18,90 TO 22,90 228 HPLOT 18,100 TO 22,100 230 HPLOT 18,1 10 TO 22,110 232 HPLOT 18,120 TO 22,120 234 HPLOT 18,130 TO 22,130 236 HPLOT 18,140 TO 22,140 238 HPLOT 18,150 TO 22,150 240 HPLOT 4,47 TO 4,53 242 HPLOT 7,53 246 HPLOT 10,47 TO 10,53 248 HPLOT TO 14,53 250 HPLOT TO 14,47 252 HPLOT TO 10,47 260 HPLOT 7,103 262 HPLOT 14,97 TO 10,97 Comments Machine language routine Starting address of data Get first digit (MSD) Get second digit Get third digit Get fourth digit (LSD) Decode MSD Convert digits into voltage XXX. X High-resolution graphics Plot X-Y axis Figure 3: Flowchart of the BASIC pro- gram which calls the machine language subroutine, formats the data obtained from the analog-to-digital converter, and displays it using high-resolution graphics. ( start J CALL MACHINE LANGUAGE ROUTINE INITIALIZE DATA STORAGE LOCATION GET 4 DIGITS FORMAT INTO VOLTAGE PLOT X, Y AXIS PLOT VOLTAGE SAMPLES YES f STOP J Listing 2 continued on page 78 shows the coded program with com- ments. Upon entering the subroutine, all of the necessary registers are saved to enable a successful return from subroutine. The first thing that happens is that the end of conversion flip-flop is reset and the program loops until the MC14433 completes the next conversion and sets the flip- flop. The program then samples the data lines and decides whether or not the data represents the most signifi- cant piece of data. If it does not, the program continues to sample the data lines until the most significant piece of data has been obtained. This datum is then stored in memory, the memory storage locations are in- 76 September 1979 © BYTE Publications Inc w^^JutMyf^fH (Mud announcement I. The first eight Personal 'rograms 8 from Aladdin Automation are waiting for you now at your neighborhood omputer retailer or direct from Aladdin. low you can get your full share of Aladdin lagic in every one of these Personal 'rograms 8 : Math-Tor-Mind A delightful, educational learning experience for your pre-school child. Watch le smile on your child's face as a correct nswer makes the mathematician smile on the :reen before you. A nursery song also serves 3 a reward for learning elementary addition nd subtraction. With Aladdin's Math-Ter- 1ind s your child's pathway to learning will be jn-filled . . . for both of you. Math-Ter-Mind 8 . ne first release from the Aladdin Education® eries. (nursery song currently available only n Apple II"" program) Lunar Lander In a controlled descent, you're |ust seconds away from your first landing on the cold. nbidding surface of the moon. As you avigate your delicate spacecraft downward to le safety of Moonbase. you must be ever /atchful of the dangers rising to meet you with ach passing moment: a fuel level fast pproaching zero; deadly meteor showers that ome from any direction, at any time; sheer- jced rock cliffs and rough terrain; choosing ^e correct landing pattern and rate of descent. Jaddin's Lunar Lander. Your chance to reach ut and touch the stars . . . without leaving the afety and comfort of your own chair. The first ?lease from the Aladdin Simulation 8 Series. Craps All eyes in the casino are on you. The dice are in your hands. Lady Luck sits at your shoulder, whispering . . . "Just one more time. Try your luck |ust one more time." You throw . . . and watch the dice tumbling on the screen. With Aladdin's Craps you play against the computer, so it's awfully tough to win. But when you do. it's an experience you're likely never to forget. Craps. An exciting, heart- pounding Personal Program 8 . The first release from the Aladdin Las Vegas* Series. Mastermind A challenging game of intrigue, centuries old, that will give you full chance to test your powers of logic, deduction and reason. And test them you will, as you try and solve the computer's puzzle, using clues as they're provided one-by-one. You control the degree of difficulty in this classic Personal Program 8 that offers one simple, yet all-consuming challenge; beat the Mastermind in a direct, one-on-one battle of wits. Aladdin's Mastermind. The first release from the Aladdin Old Favorites 8 Series. Tic-Tac-Toe Five different levels of difficulty allow a person of any age or skill to take part in this relaxing, enjoyable game that can act as a learning tool, as well. Level I. for example, is suitable for children and is excellent also for teaching simple mathematics. The computer plays just about perfectly at Level V. Just about, that is. so go ahead and take your best shot. See if you can beat the computer in this traditional favorite of young and old alike. Tic-Tac-Toe. Another first release from the Aladdin Old Favorites"' Series. Jungle Island 8 Shipwrecked in a raging storm at sea, miraculously you survive only to find yourself stranded on a seemingly deserted jungle island. Without food, water or supplies of any kind, you begin to try and find your way to safety. The computer will be your eyes and ears as you explore your jungle island and all the mysteries and dangers that lie in wait for you. Jungle Island 8 A captivating first release from the Aladdin Adventure 8 Series. Stix- Aladdin's Stix'" can be played with 2 to 5 piles of st icks and between 1 and 1 9 sticks in each pile. The object: to be the one to pick up the last stick. Sounds simple? Yes. but you're playing against the computer. Take heart, though, because you can control the degree of difficulty in this update of the ancient game of Nim. Stix 8 . Another first release from the Aladdin Old Favorites 8 Series. Super Pro Football 8 Here's your chance to be more than just an armchair quarterback. With Aladdin's Super Pro Football"' you can replay any Super Bowl game, from the first, between Green Bay and Oakland, to last year's classic victory by Pittsburgh over Dallas. For once you can turn back the clock and go for that one big play that made the difference between victory and defeat in pro football's biggest game of all. Super Pro Football 8 . The first exciting release from the Aladdin Super Pro 8 Series Visit your neighborhood computer retailer or contact Aladdin direct to get your full share of the magic in Announcement I. the first eight Personal Programs"" from Aladdin Automation. lath-Ter-Mind 8 Lunar Lander Craps Mastermind Tic-Tac-Toe Jungle Island" Stix 9 Super Pro Football* Velcome to the All-New World of uaddin. And Get Ready to flake Your Own Magic ircle 3 on inquiry card. A/CON AJVJMAWON, NC. 'AJDON COMPUTB? CORR 3420 Kenyon Street, Ste. 131, San Diego, CA 92110 opyright 1978 by Aladdin Automation Design and copy by Campbell Marsh Graphic Communications Listing 2 continued: 264 HPLOT TO 10,100 266 HPLOT TO 14,100 268 HPLOT TO 14,103 270 HPLOT TO 10,103 272 HPLOT 14,147 TO 10,147 274 HPLOT TO 10,153 276 HPLOT TO 14,153 278 HPLOT TO 14,147 280 HPLOT 30,148 TO 30,152 281 HPLOT 40,148 TO 40,152: HPLOT 50,148 TO 50,152 282 HPLOT 60,148 TO 60,152: HPLOT 70,148 TO 70,152 283 HPLOT 80,148 TO 80,152: HPLOT 90,148 TO 90,152 284 HPLOT 100,148 TO 100,152: HPLOT 110,148 TO 110,152 285 HPLOT 120,148 TO 120,152: HPLOT 130,148 TO 130,152 286 HPLOT 140,148 TO 140,152: HPLOT 150,148 TO 150,152 287 HPLOT 160,148 TO 160,152: HPLOT 170,148 TO 170,152 288 HPLOT 180,148 TO 180,152: HPLOT 190,148 TO 190,152 289 HPLOT 200,148 TO 200,152: HPLOT 210,148 TO 210,152 290 HPLOT 220,148 TO 220,152: HPLOT 230,148 TO 230,152 291 HPLOT 240,148 TO 240,152: HPLOT 250,148 TO 250,152 292 HPLOT 260,148 TO 260,152: HPLOT 270,148 TO 270,152 300 FOR J = TO 255 310 HPLOT J + 20,150 - (Z(J) * 100) 320 NEXT J 1000 PRINT "PRESS RETURN TO START A/D 1010 K = PEEK( - 16384) 1012 POKE - 16368,0 1014 IFK > 127 THEN GOTO 1020 1016 GOTO 1010 1020 TEXT 1022 HOME 1024 VTAB 24 1026 PRINT "256 DATA POINTS ARE BEING DIGITIZED" 1028 GOTO 110 1099 END Photo 1: High-resolution display of a 0.05 Hz sine wave signal which has been digitized at 10 samples per second. Plot voltage cremented, and the program begins to look for the 2nd piece of data. After the 4 digits representing the digitized voltage have been stored, the pro- gram checks to see if 256 samples have been stored. If they have not, control returns to the beginning of the subroutine. When all 256 samples have been stored, the program returns to the BASIC routine which called it. The BASIC routine has the task of assembling the 4 digits from each con- version into a single number which is equal to the measured voltage. A flowchart is shown in figure 3. The machine language assembly routine has previously taken each of the 4 digits from a single conversion and has stored them in individual memory locations. The BASIC routine uses the string manipulation capabilities of Applesoft BASIC to fetch each digit from its memory loca- tion and to assemble all 4 digits into a single 4-digit voltage. After all 256 conversions have been changed into voltages and stored in a matrix array, the high-resolution graphics routine is called and the voltages are plotted as a function of time. It is convenient to have the voltages stored in a matrix array so that if further analysis of the data is required it can be easily retrieved. Listing 2 shows the coded BASIC program with comments. To demonstrate the ability of a system to digitize and display low- frequency signals, a waveform generator was connected to the analog-to-digital converter. Photo 1 shows a 0.05 Hz sine wave which was digitized at 10 samples per second. Photo 2 shows a 0.05 Hz triangular wave which was digitized at 10 samples per second. Photo 3 shows a 0.001 Hz sine wave which was digitiz- ed at 1 sample per minute. The results are even more impressive when you consider that this is a data-acquisition Photo 2: Display of a 0.05 Hz triangular wave digitized at 10 samples per second. ..." ..■■■-.■■■-■■■■ ■ ■ wmE^ 1 ^^ Photo 3: Display of a 0.001 Hz sine wave digitized at 1 sample per minute. system costing less than $2,000. At present, a high-speed analog-to- digital converter is being constructed to digitize and analyze the electro- myographic voltages which come from muscles. This will allow an in- vestigator to gather data for further analysis of the complex neural- impulse waveform resulting from stretching a muscle. I anticipate that once researchers become aware of the data acquisition, data analysis, and system control that are possible with these low-cost systems, there will be a drastic increase in their use.H 78 September 1979 © BYTE Publications Inc Circle 99 on inquiry card. DIABLO PROVES LOOKS ARE EVERYTHING. With Diablo's printers and terminals, you can always be sure that beauty will be in the eyes of the beholder. Because no one knows more about print wheel technology than the company that invented it in the first place. Diablo's metal and plastic wheel printers have established industry standards for crisp, clear characters, proportional spacing, and uniform density. So, when you're ready to choose a printer for your own computer, pick the one that produces "picture perfect" originals every time. If you really want to look good, remember this. With Diablo, you'll always look your best. t - Diablo Systems )iaMd* is a roastered trademark of XEROX CORPORATION. ^Jp Your Output. TEMPOS MULTI-TASKING! The TEMPOS Operating System is quickly becoming the standard in Multi- User, Multi-Tasking operating systems for 8080 and Z80 microcomputers. Multi-Tasking means that, even with only one user at one terminal, more than one job can be running on the system simultaneously! If you have ever had to go get a cup of coffee while you wait for your computer to print list- ings, you know the advantages of a system that will handle one job while you are working on another. TEMPOS is a true time sharing system, and the maximum number ol jobs is limited only by your memory. MULTI-USER! Want to share your computer with another user? With TEMPOS all it takes is another terminal ... up to seven interactive terminals are allowed! And with Re-Entrant programs, each user does not need a complete copy in memory. We include three Re-Entrant programs (the OPUS/THREE High- Level Language, the TEXTED Text Editor, and FILES, a disc file directory/manipulator) or write your own! In addition, we include an assembler, a linking loader, over a half-dozen other utility programs and over 60 system subroutines, callable by the programmer! PROVEN! With TEMPOS, you get a package that has been tested in our facilities for over two years, and in the field at over 50 different installations. We have used this system ourselves for everything from writing high-level languages to developing applications to text editing to games. TEMPOS is undoubted- ly the most flexible software tool on the market . . . and you can have it for much less than you think! COMPATIBLE! TEMPOS is available for many different systems; prewritten drivers may include yours. Or, using our interactive System Generation Routine, you can add your own. Call or write now for our free catalog and the name of a dealer near you. The TEMPOS Operating System is available for $787.00, the manual set ( price may be credited toward the purchase of the TEMPOS package) for $21.50 (prices include shipping within the U.S.). ADMINISTRATIVE □□SYSTEMS □□□INC. □□ 1642 S. Parker Road, Suite 300, Denver, Colorado 80231 (303) 755-9694 BYTEs Bits EXPAND YOUR COMPUTER'S POTENTIAL WITH NEW TIMESHARING SERVICE CompuServe, a Columbus Ohio computer service organization which services more than 650 commercial customers including govern- ment agencies, financial institutions, and large cor- porations, has recently ex- panded its services to en- compass the personal com- puter user. MicroNET is a computer timesharing and software distribution service for home and small business applications. The service costs $5 per connect hour. The MicroNET system may be accessed via telephone service in 25 major metro- politan areas. It is available between the hours of 6 PM and 5 AM on weekdays, as well as all day Saturday, Sunday and holidays. According to the com- pany, the personal computer owner will be able to use a variety of computer pro- grams on a timesharing basis; communicate with other MicroNET customers; buy and sell software through the network; and obtain additional on-line storage. The MicroNET timesharing library includes a large selection of programs in several categories inclu- ding personal programs, educational aids, business applications, games and simulations, programming languages, and programming and diagnostic tools. Most of the programs in the MicroNET library are available at no charge other than the basic connect time rate. All connect time charges and software purchases will be billed through use of credit card information which is provided by the customer. For a Service Application form and more information, write to Per- sonal Computing Division, CompuServe Inc, 5000 Ar- lington Centre Blvd, Colum- bus OH 43220, or call (614) 457-8600. NOTES ON BULLETIN BOARD The Computerized Bulletin Board System (CBBS) in the Atlanta GA area is no longer being operated by DC Hayes Associates Inc. The Atlanta system is now being operated by the Atlanta Computer Society. The telephone number has been changed to (404) 394-4220. A description of a CBBS ap- peared in the article entitled "Hobbyist Computerized Bulletin Board" by Ward Christensen and Randy Suess, (November 1978 BYTE, page 150). CITRUS COLLEGE OFFERS PERSONAL COMPUTING COURSES Citrus College in Azusa CA is offering 2 personal computing courses to com- mence September 1979. Each class is 18 weeks long. The classes are: Personal Computing -Building and Using (DP 115) Basic construction techniques, reading sim- ple logic diagrams, debugging circuits, simple assembler, and simple BASIC. Personal Computing -Software (DP 116) Pro- gramming in 6800 and 8080 assembly language. For further information, contact Ed Keith, Citrus College, 18824 E Foothill Blvd, Azusa CA 91702. ■ 80 September 1979 © BYTE Publications Inc Circle 8 on inquiry card. THE BRAIN is the single topic of the September issue of SCIENTIFIC AMERICAN Is the brain a computer? What is the role of chemistry in brain function? Is the capa- city of speech "hard-wired" into the brain? Where in the brain is the mind? These are questions that will engage your interest in the September issue of SCIENTIFIC AMERICAN. This issue does not, by any means, tell you "how the brain works." That remains one of the most alluring and baffling questions on the frontier of understanding. The conver- gence of work in many dis- ciplines — from neurosurgery to linguistics — has begun to put that question, however, in ways that can yield answers. The deep new knowledge about the brain, gathered at an accelerating rate in recent years, shows this organ to be marvelously designed and capacitated beyond the wonders with which it was invested by ignorant imagination. Here are the articles: • The Brain (Introduction) The Neuron Small Systems of Neurons The Organization of the Brain The Development of the Brain The Chemistry of the Brain Brain Mechanisms of Vision Brain Mechanisms of Movement Specializations of the Human Brain Disorders of the Human Brain Thinking about the Brain WITH YOUR SUBSCRIPTION ... THIS FREE BOOK Each of the authors of this issue has made significant contribution to the growing body of knowledge about the brain. Together they offer a compre- hensive exposition of present under- standing and chart the way for con- tinuing study. With this issue the editors of SCIENTIFIC AMERICAN continue a 30-year tradition of devoting each September issue to a single topic of current scientific and public interest. Intheothermonthlyissuesourreaders enjoy a diversity of articles covering the full range of disciplines. All the major advances in science of the past three decades have been reported in our pages by the scientists who have done the research. The collaboration of our editors in the preparation of text and illustration makes this work accessible to a steadily growing worldwide readership. Why not join us at the frontiers of knowledge? You will learn why The New York Times calls our magazine "This country's and perhaps the world's outstanding forum for communication between the scientists and the intelligent public." A one-year subscription, at $18, saves you $6 on the newsstand price of $2.00. A two-year subscription, at $33, saves $15. And a three- year subscription, at $45, saves you $27. Use the coupon below, or call toll free: 1-800-648-5311. (In Nevada call 800-992-5710.) Send no money. We'll bill you. Illustration from Gregor Reisch's Mnrgariln Philosophic/!, 1504. SCIENTIFIC AMERICAN saEMini: AMERICAN HUMAN ANCESTORS As soon as your sub- scription payment is received, we will also send you Human Ancestors (regular price: $5.00) as a bonus. This 144-page anthol- ogy reports the archae- ological discoveries that unveiled the evolu- tionary stream leading to Homo sapiens, cul- minating in the growing recognition of the role of toolmaking in the process of natural selection. Name Address SUBSCRIPTION RESERVATION SCIENTIFIC AMERICAN 415 Madison Avenue, Dept. ZF, New York, NY. 10017 Yes, enter my subscription to the monthly issues of SCIENTIFIC AMERICAN for the term I have checked. As soon as my payment is received, you will also send me — abso- lutely free — the 144-page book Human Ancestors (regular price: $5.00). MY GUARANTEE I may cancel my subscription to SCIENTIFIC AMERICAN at any time and receive a refund for the unused balance. The bonus book is mine to keep. City/State/Zip □ Start my subscription with September issue □ 1 year— $18 D 2 years— $33 D 3 years— $45 (save $27) □ Bill me (save $6) (save $15) □ My payment is enclosed (International rates outside U.S. and Canada: 1 year— $22 2 years— $40 3 years— $55) ZF Circle 336 on inquiry card. BYTE September 1979 81 Technical Fonum Operating Systems Let's Have Some UNIX-Inspired Software Jim Howell, 5472 Playa Del Rey, San Jose CA 95123 I would like to add to the comments made by James Jones ("Languages Forum," April 1979 BYTE, page 245) about operating systems. First, I wholeheartedly agree with his letter. A job con- trol language like OS/370 (or most other large systems, for that matter) would be terrible for personal computer use. Aside from the pile of job control required to do anything, there are other problems with OS-like systems. The numerous file formats and "access methods" make it difficult for programs to work together. Specifying files for the compiler or assembler to use as work files is a nuisance. A file specification (DD statement) also re- quires giving values for several parameters about which the user usually doesn't care or shouldn't have to specify. Some of these problems are helped by using procedures (sets of job control that the computer vendor or local systems programmer has stored on disk for general use), but these may not be what you need, and they also take up disk space. The space is not significant if your disks store 100 megabytes, but it could be significant for flop- py disk users. I would like to strengthen Mr Jones' suggestions that UNIX be used as a model for a microprocessor operating system. (UNIX is a trademark of Bell Labs.) I have used a UNIX system at work for about a year and it is a very pleasant system to work with. All files on UNIX are a series of bytes: no structure within files are imposed by the system. In particular, there is no concept of a "logical record" in UNIX. A "logical record" is the (usually) fixed size chunk in which files are read or written on big systems; often 80 bytes (for card or card-image files), or 120 or 132 bytes (for line printers). On UNIX, the end of a line in a text file is indicated by the use of a new-line character. This new-line character (line feed on UNIX) replaces the trailing blanks which are stored on systems that use logical records. The new-line character is read or written just like any other character. The size of a file is determined by how many bytes are written to it; pre- determination of the file size (by guessing?) is not necessary, or even possible. Job control language on UNIX is practically non- existent. A command to run a program (such as a com- piler or a user program) consists of the name of the pro- gram to be executed followed by any parameters that the program needs, separated by blanks. (Parameters are often file names and processing options.) The command processor, which runs as a user program, reads the com- mand line, divides it into "words," and calls the system to execute the desired program. This system call also passes the parameters to the executed program. There is no need to describe files in the command since programs need on- ly the name of a file in order to access it. Block sizes and such things are not required, even for new files, since there is only one format for files. The following is a summary of the major system calls of UNIX that deal with file or an I/O (input/output) device. A file name in the open and create calls can also be a device name (such as the name for a terminal or printer). Open (name, mode) opens an existing file (or device) for further operations. "Name" is a pointer to a character string which is the name of the file (or device) and "mode" indicates reading, writing, or both. Create (name, prot) creates a new file, deleting any old file whose name is "name." This new file is open- ed for writing. (I would like to see a "mode" argument for this call, in addition to the two specified. This "mode" would mean the same as it does for "open.") Read (fildes, buffer, length) reads up to "length" bytes from the file whose descriptor is "fildes" into the "buffer". The file descriptor is a small, non- negative integer which was returned by open or create. The number of bytes actually read is returned to the caller. A return of means end of file. Write (fildes, buffer, length) writes "length bytes to the file "fildes" from the "buffer." Seek (fildes, offset, base) moves the read/write pointer of the file "fildes" to a new position within the file. "Offset" is how far to move the pointer, and "base" indicates from the start of the file, from the current position, or from the end of the file. Close (fildes) closes a file. Each open file has a read/write pointer associated with 82 September 1979 © BYTE Publications Inc it. Each read or write call starts reading or writing at the current pointer and advances the pointer by the number of bytes read or written. By moving the read/write pointer with the "seek" call, random access files (or even indexed-sequential or other access methods) can be implemented if required. Note that "read" and "write" are the lowest levels of I/O calls to the system, and that they apply to all devices. All device-dependent processing is inside of the operating system. The only thing that a user program needs to know about a file after it is opened or created is the returned number (file descriptor). There are no "control blocks" or other system-imposed structures in user programs. (System calls are available in UNIX to determine the type of device that is associated with an open file for the few programs that need this information.) Most current microprocessor operating systems use a special character, such as control-z, to mark the end of text files. These systems take the view that "binary" files (files where all 256 possible bytes are valid) are only for executable programs, and in this case reading a few extra bytes from the last sector of the file will not cause any problems. Such a scheme prevents the use of binary files for other purposes where the exact end of the file must be known. Possible uses include a work file written by a compiler or assembler and libraries of subroutines in ob- ject format for linking with other programs. (For example you wouldn't want a 20 byte absolute value function to add 128 bytes to your program, simply because the end of a sector is the best you can do at locating the end of the function!) The end of a file should, as in UNIX, be indi- cated by a count of the number of bytes in the file, and the end of file when reading should be determined by comparing the read/write pointer of the file to the end-of- file byte count. (Writing past the end of a file causes the end of file pointer to move to the new read/write pointer position.) The above is a description of some aspects of UNIX, and is also intended to be used as guidelines in writing any new operating systems for microprocessors (or even big systems). One other thing that might be considered by an operating system writer is the use of a high-level language for most of the operating system and for the programs that implement supplied commands. This would allow the operating system to be moved to another microprocessor without having to completely rewrite it. I am about halfway through designing an operating system along the lines of the above suggestions. (I started before Mr Jones' letter appeared in BYTE.) Eventually I expect to implement it. Let me conclude by listing three references which are recommended to those who are implementing a usable microprocessor operating system. The first two were also mentioned by Mr Jones. ■ REFERENCES 1. Communications of the ACM, July 1974. A revised version of the UNIX article appears in reference 3 below. 2. Software Tools by Kernighan and Plauger. 3. The Bell System Technical Journal, July thru August 1978, part 2. This issue contains about fifteen papers on UNIX. Read especially the first 3 or 4 papers, as well as the one called "UNIX on a Microprocessor" (single-user version on an LIS-11). Circle 132 on inquiry card. If you own an IBM Selectric® you already have a high quality output printer. • Escon printer conversion fits right in • Installation does not affect: Shape or normal functioning of typewriter nor eligibility for IBM warranty and service • Available in S-100, Parallel, RS-232 or IEEE-488 • Entire high quality printer system for TRS-80, Apple, PET, Sorcerer, Horizon, etc. • All systems assembled, tested and burnt-in • Factory installations available; complete systems with typewriter available Prices* S-100 $496.00 Parallel $525.00 RS-232 $549.00 IEEE $575.00 * Prices valid in USA only Escon Products, Inc. 171 Mayhew Way, Suite 204, Pleasant Hill, CA 94523 (415) 935-4590 It's LOGIC for graphics! NEW ASSEMBLY LANGUAGE 3D GRAPHICS FOR THE APPLE II . . . Our 3D packages allow you to animate 3D or 2D data bases created with standard XYZ coor- dinates. The two users manuals (90 pages total) are written at different technical levels to give all Apple users a quick understanding of access and uses from BASIC and assembly language. The small 8K memory -n,. * requirement lets you use the B- .... Js«*!«__. subroutine with most of your ■^ — ■-- | educational, scientific, and game programs. S45 (available August 25, 1 979). Disc and relocat- able cassette option available. We re open 9 to 6. Monday thru Friday, central lime Give us a call The engineering & graphics people (217)367-0299 LOGIC 'BoxV, Savoy, I L 61874 Circle 353 on inquiry card. September 1979 © BYTE Publications Inc 83 Soldering Techniques William Trimmer 40 James St Morris Plains NJ 07950 Anyone who can get 3 objects into the same vicinity can solder. Doing a professional job, however, requires some care and practice. This article draws on my experience in teaching electronics and a fine pamphlet prepared by NASA entitled "Solder- ing Electrical Connections, A Hand- book" (United States Printing Office, NASA SP-5002). Good soldering Photo 1: After cleaning the tip of the soldering iron with a wet sponge, prepare it by adding a dab of solder. Photo 2: Before soldering, the joints should be mechanically fastened. techniques can save time, com- ponents and frustration. Good Soldering Techniques Good soldering starts with a clean soldering iron tip and well-tinned parts. Just prior to use, the hot solder- ing iron should be cleaned by wiping it across a wet sponge. The thermal shock and wiping action will clean the tip and remove the excess solder. Then touch a bit of solder to the tip (photo 1). The iron is now ready for use. The parts to be soldered are ready when the solder flows quickly and evenly over their heated surfaces. If this does not happen, clean the parts by brushing, filing, or rubbing with a pencil eraser. Next flow a thin layer of solder over the clean surface. The parts are now tinned and ready to be soldered. The prepared parts should be mechanically fastened together before making the soldering joint (photo 2). The solder should not be expected to supply mechanical strength. Clean the soldering iron tip, and add a dab of solder to the tip. Touch the soldering iron to the heavier of the parts to be joined, and begin wiping the solder on the junction between the two parts (photo 3). Do not feed the solder into the soldering iron tip. When the com- ponents are hot enough, the solder will begin to melt into the joint. The solder should skate over the surfaces like butter on a hot pan. Now you must move quickly. Rapidly wipe the entire length of the connection with the solder, being careful not to apply too much. The solder should flow smoothly over the parts. If braided wire is used, the strands should still be visible (photo 4). Doing this well takes a lot of practice. Now remove 84 September 1979 © BYTE Publications Inc MI ■■■■ : 'v;' II I ■ : i, - - ... WE HAVE YOUR NOVATIOI MODEMS, RIGHT NOW. Whether you need an acoustic or direct connect, your Novation modem is in stock today at your nearby Ham- ilton/Avnet location. Novation makes a wide range of modems, each with built- in economy, reliability, and quality that can enhance the efficiency and aesthetics of your system. That includes Cat™, a breakthrough for modems. Sleek, silent, compact, Cat is Novation's new acoustically coupled modem designed especially for the small computer user. Easy to use, simple to install, Cat is ideal for both small business and personal computer applications. You can get your Novation modem locally from us. We have a complete on-hand selection of Novation modems, plus all the other computer products you need, at each of our locations nationwide. And if you call our toll-free number, we'll tell you about our new Authorized Hamilton/Avnet Dealer program and the name of your nearest Authorized Dealer. He has your Novation modems in stock, too, as well as all the other computer products you need. Just call 1-800-421-4645 (in California call 1-800-252- 0627). You can get your Novation modem, right now. Hamiltonfiy^et ELECTRONIC S UiBiy •■***" *WK NOVATION FROM HAMILTON/AVNET World's largest local distributor with 39 locations stocking the world's finest lines of system components WE HAVE LOCAL STOCK! Circle 160 on inquiry card. SOUTHERN CALIFORNIA Hamilton, LA 1213) 558 2121 Avne!, L.A. 12131 558 2345 SOUTHWEST San Diego (714) 279-2421 Orange County 1714) 754 6111 Phoenix 16021 275-7851 (4081 743 3355 1206) 746-8750 ROCKY MOUNTAIN Salt Lake City (801 ) 972 2800 Dcnyer I3D3I 534 1212 Albuquerque (505)765 1500 NORTH CENTRAL Chicago Minneapolis Milwaukee MID CENTRAL Kansas City St. Louis 1312)678 6310 1612) 941 3801 (414) 784 4510 (913) 886-8900 1314) 731-1144 GREAT LAKES Cleveland (216)8313500 Dayton (513)4330610 Detroit (313) 522-4700 SOUTH CENTRAL Dallai Houston Austin NORTHEAST Boston Syracuse Rochester 1214)661-8661 1713) 780 1771 1512) 837 8911 (6171 273 7500 13151 437 2641 (716) 442 7820 METROPOLITAN Long Island (516) 333 5800 Connecticut (203) 7620361 No. New Jersey (201)5753390 MID ATLANTIC Baltimore (301) 796 5000 So. New Jersey (609)4240100 Raleigh (919) 829-8030 SOUTHEAST CENTRAL Atlanta (404) 4480800 Huntsville (205) 837 7210 SOUTHEAST St. Petersburg CANADA (8131 576 3930 (305! 971 2900 (416)677 7432 1514)331 6443 (613) 226 1700 Toi Montreal Ottawa INTERNATIONAL Telex 66-4329 Telephone 1213)5582441 Japan Telex 252-3774 Japan Telephone (03) 662 991 1 BYTE September 1979 85 Photo 3: When soldering, touch the iron to the heaviest part. When the joint is hot enough, the solder will melt on the side opposite the iron. the iron and hold everything perfectly still. Any motion while the solder is going from the liquid to the solid state will cause a cold joint. After the joint is cooled, the surface of the solder should look like a mirror. A good solder joint is an accomplishment. A good way to begin might be to deliberately make some bad soldering joints. First, shake the two wires while the solder is cooling. Notice the undesirable frosted look. Now try leaving the iron on the joint for more than several seconds, and you will notice that a scum forms. Try putting too much solder on the joint. Often when this blob cools, the frosted sur- face will appear (photo 5). Try to find the two oldest wires you can. Twist them together and solder them. If they are covered with an oxide layer, the solder will not transfer from the soldering iron tip to the wires. Repeated heatings will probably cause the solder to melt around the joint. Notice how the solder does not flow onto the wires, but sticks to itself. The joint is now probably hot enough to burn the flux. Inevitably, one has to unsolder some beautifully soldered joints. If the joint is that of a straight wire through a hole, a pull will often ac- complish the task. (Be careful of the flying molten solder.) Often, one must remove the solder and then un- wrap the wire. The best method uses a fine mesh of properly fluxed copper wire. (An example of this would be Solder-Wick, made by Solder Photo 4: In a well-soldered braided wire, the strands should still be visible. Photo 5: Excess solder, poor wetting of the wire, frosted surfaces, and blobs of solder represent poorly soldered joints. Removal Co, 1077 E Edna Place, Covina CA 91724. Their 40-4-5 is a medium size, 40-6-2 Vi is for large joints, and 40-2-5 is for very small joints.) Push the mesh against the joint with the soldering iron. The solder will be wicked from the joint into the mesh. Solder suckers are also a popular way to remove solder. The tool is cocked, placed on a heated joint, and released. A plunger pulling air through the nozzle of the sucker gets most of the solder. This last sug- gestion is the least expensive way. Hold the circuit board and heat the joint. Rap the edge of the board smartly on the work bench. Solder flies in every direction, but the joint is clean. Good soldering takes patience and practice. Fortunately, if properly done, the soldering joints are almost never the culprits when a circuit does not work. The following are some suggestions that will make soldering easier. Tools The soldering iron should be well tinned (covered with solder), and should quickly raise the joint to the working temperature. I prefer a 30 or 40 W element for a pencil soldering iron. Cleaning the tip with a wet sponge before soldering will bring the tip down to the correct temperature range (about 700 °F). This slightly greater wattage will allow larger pieces to be soldered. Better yet are the temperature controlled pencil soldering irons. Soldering guns are too large and hot for all but the most massive soldering joints. If you buy a new soldering iron, wrap the tip with solder before turning it on. This will coat the tip with solder before it gets hot enough to oxidize. Place the iron in a protective cage towards the back of your work bench so that it can not burn anything. If the iron is not going to be used for a while, unplug it. It is very tempting to buy less ex- pensive solder. Don't do it. Solder costs very little compared to other components. The best solder is Eutec- tic, which is 63% tin and 37% lead. This mixture passes directly from a liquid to a solid stage without going through a plastic region. As a result, good soldering joints are easier to make. Solder composition is gener- ally given by two numbers, such as 40-60. The first number is the amount of tin, the second is the amount of 86 September 1979 © BYTE Publications Inc lead. The above solder is less expen- sive to make than Eutectic solder because tin is the expensive element. However, this solder has a plastic region of about 180 °F. The joint must be held completely motionless while the solder is cooling through this plastic stage. Always use a rosin flux when soldering. Never let your iron touch acid flux. An 18 or 20 gauge solder with a rosin core works nicely. There are a number of other useful tools. These include long nose pliers, diagonal cutting pliers, wire strip- pers, a slotted screwdriver, a dental pick, and plastic electrical tape. Assembly Before Soldering A convenient substrate upon which to build electronics is predrilled epoxy board. The holes should be on 0.1 inch centers in a square grid for digital work. Typical hole sizes are 0.042 or 0.062 inches. Vector-type terminals (Vector Electronic Co Inc, 12460 Gladstone Ave, Sylmar CA 91342) can be pushed into the holes and the discrete components soldered to the terminals. The majority of digital electronics come in the dual- in-line packages. A convenient way to mount dual-in-line packages is with circuit-stick-type subelements (Circuit-Stik Inc, 24015 Gardnier St, POB 3396, Torrance CA 90510). These are very thin sheets of glass epoxy with preetched copper lands on one side and glue on the other. The holes on the subelements are aligned with the holes on the predrilled circuit board, and carefully pressed together. The dual-in-line packages and components can then be pushed through from the other side of the board, and soldered to the preetched copper lands. One can then wire the correct lands together. Because the spacing between the pins of the dual- in-line packages is only 0.1 inches, hand soldering requires care. When working with dual-in-line packages, I prefer to solder sockets onto the board, and plug the dual-in-line packages into the sockets. This method makes troubleshooting easier. It is important to be neat when soldering. Try to lay the board out logically. Do not crowd the com- ponents together. If it is your own design, you will probably want to add something after the board is made. Place all of the resistors the same way so that their color codes Explorer/85 Professional Computer Starting at just SI 29. 95 for a Level "A" operating system, you can now build the exact computer you want. Explorer/85 can be your beginner's system, OEM controller, or IBM- formatted 8" disk small business system. . .yet you're never forced to spend a penny for a component or feature you don't want and you can expand in small, affordable steps! Now, for just $129.95, you can own [he first level of a fully expandable computer with professional capabilities — a com- puter which features the advanced Intel 8085 cpu, thereby giving you immediate access to all software and development tools that exist for both the 8085 and its 8080A predecessor (they are 100% software compatible) — a computer which features onboard S-100 bus expansion — plus instant conver- sion to mass storage disk memory with either 5-1/4" diskettes or standard IBM-formatted 8" disks. For just $129.95 (plus the cost of a power supply, keyboard/ terminal and RF modulator, if you don't have them already),, Explorer/85 lets you begin computing on a significant level. . . applying the principles discussed in leading computer maga- zines. . .developing "state of the art" computer solutions for both the industrial and leisure environment. Like all Netronics products, each level of Explorer/85 is engineered to professional standards. Top quality components are used throughout. You are insured, year after year, of stable, reliable service. And Netronics lets you build the system you want— with the exact components you want. You're never forced to spend a penny for an item you already have (i.e., a power supply, RF modulator, keyboard, etc.) in order to get a new feature or component you need. No matter what your future computing plans may be, Level "A" is your starting point. Level "A" Specifications Explorer/85's Level "A" system features the advanced Intel 8085 cpu, an 8355 ROM with 2k deluxe monitor/operating system, and an 8155 ROM-l/O— all on a single motherboard with room for RAM/ROM/PROM/EPROM and S-100 ex- pansion, plus generous prototyping space. (Level "A" makes a perfect OEM controller for indsutrial applications and is available in a special Hex Version which can be programmed using (he Netronics Hex Keypad/Display.) PC Board: glass epoxy, plated through holes with solder mask • I/O: provisions for 25-pin (DB25) connector for terminal serial I/O, which can also support a paper tape reader . . .provision for 24-pin DIP socket for hex keyboard/display . . . cassette tape recorder input . . . cassette tape recorder output . . . cassette tape control output . . . speaker output . . . LED out- put indicator on SOD (serial output) line. . .printer interface (less drivers). . .total of four 8-bit plus one 6-bit I/O ports • Crystal Frequency: 6.144 MHz • Control Switches: reset and user (RST 7.5) interrupt . . . additional provisions for RST 5.5, 6.5 and TRAP interrupts onboard • Counter/Timer: program- mable, 14-bit binary • System RAM: 256 bytes located at F800, ideal for smaller systems and for use as an isolated stack area in expanded systems. . .RAM expandable to 64k via S-100 bus or 4K on motherboard. Monitor ROM (ASCII Keyboard Version): 2k bytes of deluxe system monitor ROM located at F000 leaving 0000 free for user RAM/ROM. Features include tape load with labeling (so that Explorer/85 can locate your specific program auto- matically). . .tape dump with labeling. . .examine/change contents of memory. . .insert data (such as from a paper tape reader). . .warm start (a feature which is especially helpful in debugging routines as it allows you to save the contents of the registers which might otherwise be lost along with the rest of your program when a bug causes it to self-destruct. The warm start feature helps you pinpoint the exact line in your program that contains an error). . .examine and change all registers. . . single step with register display at each break point, a debugging/training feature ..go to execution address... move blocks of memory from one location to another. . .fill blocks of memory with a constant . . . display blocks of memory . . .automatic baud rate selection . . . variable display line length control (1-255 characters/line). . .channelized I/O monitor routine with 8-bit parallel output for high spe ed p rinter . . . ^NeTronTcsR ftDLtaT, Bep™ Y? ^ - | 333 Litchfield Road, New Milford, CT 06676 I Please send the items checked below — D Explorer/85 Level "A" Kit (ASCII I Version), $129.95 plus $3 p&h. □ Explorer/85 Level "A" Kit (Hex I Version), $129.95 plus $3 p&h. □ 8k Microsoft BASIC on cassette I tape, $64.95 postpaid. D 8k Microsoft BASIC in ROM Kit I (requires Levels "B," "D," and "E"), $99.95 plus $2 p&h. □ Level "B" (S-100) Kit, $49.95 plus $2 p&h. D Level "C" (S-100 6-eard expander) Kit, $39.95 plus $2 p&h. □ Level "D" (4k RAM) Kit, $69.95 plus $2 p&h. □ Level "E" (EPROM/ROM) Kit, $5.95 plus 50C p&h. D Deluxe Steel Cabinet for Explorer/ 85, $49.95 plus $3 p&h. □ ASCII Keyboard/Computer Ter- minal Kit (features a full 128 character set, upper & lower case, full cursor con- trol, 75 ohm video output convertible to baudot output, selectable baud rate, RS232-C or 20 ma. I/O, 32 or 64 char- acter by 16 line formats, and can be used with either a CRT monitor or a TV set (if you have an RF modulator), $149.95 plus $2.50 p&h. By Netronics serial console in and console out channel so that monitor can communicate with I/O ports. Monitor ROM (Hex Version): Tape load with labeling. . . tape dump with labeling. . .examine/change contents of mem- ory... insert data... warm start. . .examine and change all registers. . .single step with register display at each break point . . .go to execution address. Level "B" Specifications Level"B" provides the S-100 signals plus buffers/drivers to support up to six S-100 bus boards and includes: address decoding for onboard 4k RAM expansion selectable in 4k blocks. . .address decoding for onboard 8k EPROM expansion selectable in 8k blocks. . .address and data bus drivers for onboard expansion . . . wait state generator (jumper selectable), to allow the use of slower memories. . .two separate 5 volt regulators to insure maximum stability and a noise free bus. Level "C" Specifications Level "C" expands Explorer's motherboard with a card cage, allowing you to plug up to six S-100 cards directly into the motherboard. Both cage and cards are neatly contained inside Explorer's deluxe steel cabinet. Level "C" includes a sheet metal superstructure, a 5-card gold plated S-100 extension PC board which plugs into the motherboard, 12 card guides, and all brackets and hardware needed for complete assembly. Just add required number of S-100 connectors In addition to six S-100 cards, Level "C" will also support an optional test socket that allows you to perform tests and maintenance on both sides of any individual S-100 card, under actual operating conditions. (You won't need Level "C" unless you are planning to use 3 or more S-100 cards with your Explorer/85.) Level "D" Specifications Level "D" provides 4k or RAM, power supply regulation, filtering decoupling components and sockets to expand your Explorer/85 memory to 4k (plus the original 256 bytes located in the 8155A). The 21 14 static RAM is organized as 1024 words by 4-bits using N-channel Silicon-Gate MOS technology and can be located anywhere from 0000 to EFFF in 4k blocks. Level "E" Specifications Level "E" adds sockets for 8k of EPROM to use the popular Intel 2716 or theTl 2516. It includes all sockets, power supply regulator, heat sink, filtering and decoupling components. Sockets may also be used for soon to be available RAM IC's (allowing for up to 12k of onboard RAM). Order A Coordinated Explorer/65 Applications Pak! Experimenter's Pak (SAVE $12.50)— Buy Level "A" and Hex Keypad/Display for $199.90 and get FREE Intel 8085 user's manual plus FREE postage& handling! Student Pak (SAVE $24.45)— Buy Level "A," ASCII Key- board/Computer Terminal, and Power Supply for $319.85 and get FREE RF Modulator plus FREE Intel 8085 user's manual plus FREE postage & handling! Engineering Pak (SAVE $41.00)— Buy Levels "A," "B," "C," "D," and "E" with Power Supply, ASCII Keyboard/ Computer Terminal, and six S-100 Bus Connectors for $514.75 and get 10 FREE computer rrade cassette tapes plus FREE 8085 user's manual plus FREE postage & handling! Business Pak (SAVE $89.95)— Buy Explorer/85 Levels "A," "B," and "C" {with cabinet), Power Supply, ASCII Key- board/Computer Terminal (with cabinet), 16k RAM, 12" Video Monitor, North Star 5-1/4" Disk Drive (includes North Star BASIC) with power supply and cabinet, all for just $1599.40 and get 10 FREE 5-1/4" minidiskettes ($49.95 value) plus FREE 8085 user's manual plus FREE postage & handling! Continental U.S.A. Credit Card Buyers Outside Connecticut CALL TOLL FREE 800-243-7428 To Order From Connecticut Or For Technical ™~ Assistance, Etc. Call (203) 354-9375 | sonalized disk operating system— just m plug it in and you're up and running!), I $699.95 plus $5 p&h. □ Power Supply for North Star Disk I Drive, $39.95 plus $2 p&h. D Deluxe Case for North Star Disk I Drive, $39.95 plus $2 p&h. D Experimenter's Pak (see above), I $199.90 postpaid. D Student Pak (see above), $319.85 1 postpaid. G Engineering Pak (see above), | $514.75 postpaid. ■ □ Business Pak (see above), $1599.40 1 postpaid. D Deluxe Steel Cabinet for ASCII Keyboard/Terminal, $19.95 plus $2.50 p&h. □ Power Supply Kit ( ± 8V @ 5 amps) in deluxe steel cabinet, $39.95 plus $2 p&h. D Cold Plated S-100 Bus Connectors, $4.85 each, postpaid. □ RF Modulator Kit (allows you to use your TV set as a monitor), $8.95 postpaid. □ 16k RAM Kit (S-100 Board expands to 64k), $199.95 plus $2 p&h. □ 32k RAM Kit, $329.95 plus $2 p&h. D 48K RAM Kit, $459.95 plus $2 p&h. D 64k RAM Kit, $589.95 plus $2 p&h. D 16k RAM Expansion Kit (to expand any of the above up to 64k), $139.95 plus $2 p&h each. D Intel 8085 cpu User's Manual, $7.50 postpaid. D Special Computer Grade Cassette Tapes, $1.90 each or 3 for $5, postpaid. D 12" Video Monitor (10 MHz band- width), $139.95 plus $5 p&h. D North Star Double Density Floppy Disk System (One Drive) for Explorer/ 85 (includes 3 drive S-100 controller, DOS, and extended BASIC with per- Total Enclosed $ 1 (Conn. res. add sales tax) By — D Personal Check D M.O. /Cashier's I Check □ Visa □ Master Charge | (Bank #_ Signature . Print Name _£xp. Date _ City. _Zip„ D Send Me Information Circle 280 on inquiry card. September 1979 © BYTE Publications Inc 87 Circle 141 on inquiry card. 16K Static RAM Boards for the < SS-50 Bus ^ • Gold bus connectors • 4 separate 4K Blocks • Individual Addressing, Write Protect, and Enable/ Disable for each block Memories. . . s 298 13 As above with Sockets and Software control features. s 368 16 All GIMIX memory boards are assembled, Burnt-ln for 2 weeks, and tested at 2 MHz. Add $32.00 for 250 ns parts 8K PROM BOARD $98.34 2708s $7.90 each SS 50 BUS 80 x 24 VIDEO BOARD ill TXT SgJ With hardware scrolling, x-y addressable cursor and multiple character generators. It includes a TMS 2716 EPROM that contains a full 128 upper and lower case ASCII character set with true descenders; plus a socket for another TMS 2716 for an optional 128 character set; plus 2K of RAM for user-defined programmable character sets. This gives the user the ability to create his own heiroglyphics, alphabet, graphic elements, etc., and store them on PROM, disk, or tape. The user can choose and intermix 384 different characters from any or all of the character generators and display up to 256 at one time, normally or inversely, and at full or half intensity, at any location on the screen. Contiguous 8x10 character cells permit solid lines and connecting patterns with user definable graphic elements. It is addressable to any 2K boundary. GHOSTable ad- dressing allows multiple boards at the same address, making it ideal for multi-user applications. The available software includes a GMXBUG video based 3K ROM monitor, stand alone driver routines, and a program to create user defined characters. DELUXE VERSION $458.76 Other Video Boards from $198.71 16K SYSTEMS $1294.29 Includes: Mainframe cabinet, mother board, power supply, fan, CPU, 16K static RAM, and choice of 1/0 card. Other packages available. Add $10. handling charge on orders under $200. inc. Gimix 1337 WEST 37th PLACE CHICAGO, ILLINOIS 60609 (312) 927-5510 • TWX 910-221-4055 The Company that delivers. Quality Electronic products since 1975. AWG Diameter (mm) Ohms per 1000m Current Capacity (Amperes) 10 2.6 3.3 26 12 2.0 5.2 16 14 1.6 8.3 10 16 1.3 13 6 18 1.0 21 4 20 0.81 33 2.5 22 0.64 53 1.6 24 0.51 84 1.0 26 0.40 135 0.6 28 0.32 214 0.4 30 0.25 341 0.2 Table 1: Approximate values for various American Wire Gauge (AWG) sizes of copper wire. can be read from the same side of the board. Run the wires in an orderly manner. I prefer to mount com- ponents like resistors, transistors, etc, slightly off the board. This improves the heat transfer, and makes it easier to slip in a probe for testing. Com- ponents that weigh 0.5 ounces or more should be mechanically mounted to the board. A little epoxy or silicon rubber works wonders for mounting these components. Properly stripping wire is a dichotomy. First, the insulation should be cut and removed. Second, the wire should not be cut. (If strand- ed wire is used, a nick will cause only a few strands to break.) With prac- tice, you can strip the insulation without cutting the wire. Try cutting slowly through a wire. Notice the dif- ference in the feel between the insula- tion and wire. Now cut off the wire and start again with a clean end. Cut down until the wire is felt, then relax the stripper slightly. Now rotate the wire 45° and again squeeze a bit. This will cut the insulation all the way around, not just where the stripper teeth cut the deepest. Be sure to open the stripper slightly and pull the in- sulation off the wire. With practice, you can learn not to nick the wire. The secret is to stop cutting just before the cutter reaches the wire. A firm pull will usually break off the re- maining insulation. If you still nick the wire, take heart, you have much company. Table 1 gives the American Wire Gauge (AWG) size, the approximate diameter, ohms per 1000 meters, and current carrying capability of copper wire. Try to use a number of wires of different colors and gauges. This not only matches the current capability with the load, but also makes it easier to trace wires. Finally, some words on safety: be sure that you have a stand for your iron; always wear shoes and safety glasses; and try not to flick solder on anything important. When cutting wires, hold the cutter so that the pieces fly away from you. To avoid potentially lethal shocks, it is best to have a rubber mat beneath your feet and stool. By following these rules and tech- niques, almost anyone can learn to solder well.H "WE WILL RETURN TO OUK PROS^M « JU57" -1 MOMENT, BUT' FlRST ft MESSAGE ffX». OUR SPONSOR, ' 88 September 1979 © BYTE Publications Inc POWER-ONE D.C. POWER SUPPLIES Now available for small systems applications Power-One, the leader in quality open-frame power supplies, now offers a complete line of single, dual, and triple output models for small computer systems. Also available are special purpose models for Floppy Disk and Microcomputer applications. Below are just a few popular examples of the over 90 "off the shelf" models now available from stock. SINGLE OUTPUTS LOGIC POWER SUPPLIES • 56 "off the shelf " models •2Vto250V,0.1Ato40A • ± .05% regulation • 115/230 VAC input 5V@3A,w/OVP HB5-3/OVP $24.95 single qty. 5V@ 12A,w/OVP HD5-12/OVP $79.95 single qty. 5V @ 40A, w/OVP «tiv m SK5-40/OVP Switching Model $250.00 single qty. FLOPPY-DISK SERIES • 8 "off the shelf" models • Powers most popular drives • Single/dual drive applications • 2-year warranty 5V @ 0.7A, w/OVP /l/Jfr,. 1.1A/1.7APK*^W 12V 5V@ 1A, w/OVP -5V@0.5A, w/OVP 24V @ 1.5A/1.7APK 5V @ 2.5A, w/OVP -5V@0.5A, w/OVP 24V @ 3A/3.4A PK CP340 For one 5.25" Media Drive $44.95 single qty. CP205 For one 8.0" Media Drive $69.95 single qty. CP206 For two 8.0" Media Drives $91 .95 single qty. 12V/15V DUAL OUTPUT MODELS • 15 "off the shelf" models • ±5Vto ±24V, 0.25A to6A • I.C. regulated • Full rated to +50°C 5V @ 2A, w/OVP 9-15V@0.5A ±12V ±15V 1.7Aor 1.5A HAD12-.25/HAD15-.25 $32.95 single qty. HAA512 $44.95 single qty. HBB15-1.5 $49.95 single qty. TRIPLE OUTPUT MODELS • 10 "off the shelf" models • 5V plus ± 9V to ± 15V outputs • Models from 16W to 150W • Industry standard size 5V@2A, w/OVP ± 9Vto ± 15V@0.4A 5V@3A, w/OVP ±12V @ 1Aor ± 15V @ 0.8A 5V@6A, w/OVP ±12V@1.7Aor ±15V@1.5A HTAA-16W $49.95 single qty. HBAA-40W $69.95 single qty. HCBB-75W $91. 95 single qty. &xsy$* NEW 79' CATALOG! Get Your FREE Copy Now! Phone us direct or circle the reader service number below. & oeui %L&* power-one D.C. POWER SUPPLIES Power One Drive • Camarillo, CA 93010 • (805) 484-2806 • TWX 910-336-1297 Circle 309 on inquiry card. BYTE September 1979 89 Software / with / Manual Manual/ Alone DIGITAL RESEARCH D CP/M* Floppy Diskette Operating System — Packages supplied on diskette complete with 8080 as- sembler, text editor, 8080 debugger and various utilities plus full documentation. CP/M available configured for most popular computer/disk systems including: North Star Single, Double or Quad density, Altar 8" disks, Helios II, Exidy Sorcerer, Vector MZ, PolyMorphic 8813t* Heath H17t or H89f, TRS-80t, iCOM 3712 and iCOM Micro Disk plus many other configurations avail- able off the shelf $145/525 □ MAC — 8080 Macro Assembler. Full Intel macro defini- tions. Pseudo Ops include RPC, IRP, REPT, TITLE, PAGE, and MACLIB. Z-80 library included. Produces Intel absolute hex output plus symbols file for use by SID (see below) $1 00/S1 5 □ SID — 8080 symbolic debugger. Full trace, pass count and break-point program testing system with back-trace and histogram utilities. When used with MAC, provides full symbolic display of memory labels and equated values $85/$1 5 □ TEX — Text formatter to create paginated, page- numbered and justified copy from source text tiles, di- rectable to disk or printer $85/$ 1 5 Q DESPOOL — Program to permit simultaneous printing of data from disk while user executes another program from the console $50/$1 (M-M^f^L. OM □ □ □ □ □ □ MICROSOFT Disk Extended BASIC — Version 5, ANSI compati- ble with long variable names, WHILE/WEND, chaining, variable length (He records S300/S25 BASIC Compiler — Language compatible with Ver- sion 5 Microsoft interpreter and 3-10 times faster execu- tion. Produces standard Microsoft relocatable binary out- put. Includes Macro-80. Also linkable to FORTRAN-80 or COBOL-80 code modules S350/S25 FORTRAN-80 — ANSI '66 (except for COMPLEX) plus many extensions. Includes relocatable object com- piler, linking loader, library with manager. Also includes MACRO-80 (see below) S400/S25 COBOL-80 — ANSI 74 Relocatable object output. Format same as FORTRAN-80 and MACRO-80 modules. Complete ISAM, interactive ACCEPT/DIS- PLAY, COPY, EXTEND S625/S25 MACRO-80 — 8080/Z80 Macro Assembler. Intel and Zilog mnemonics supported. Relocatable linkable output. Loader, Library Manager and Cross Reference List utilities included $149/$15 EDIT-80 — Very fast random access text editor for text with or without line numbers. Global and intra-line com- mands supported. File compare utility included S89/S15 Software / with /Manual Manual/ Alone XITAN (software requires ZBO" CPU) □ Z-TEL — Text editing language. Expression evaluation iteration and conditional branching ability. Registers available for text and commands. Macro command strings can be saved on disk for re-use $69/$20 □ ASM Macro Assembler — Mnemonics per Intel with Z-80 extensions. Macro capabilities with absolute Intel hex or relocatable linkable output modules. New version 3 with added features S69/$20 D LINKER — Link-edits and loads ASM modules S69/S20 □ Z-BUG debugger — Trace, break-point tester. Supports decimal, octal and hex modes. Disassembler to ASM mnemonic set. Emulation technique permits full tracing and break-point support through ROM S89/S20 □ TOP Text Output Processor — Creates page-numbered, justified documents from source text files . . . $69/$20 □ A4 package includes z-tel, asm, linker, z-bug, TOP $299/$40 EIDOS SYSTEMS □ KISS — Keyed Index Sequential Search. Offers com- plete Multi-Keyed Index Sequential and Direct Access file management. Includes built-in utility functions for 16 or 32 bit arithmetic, string/integer conversion and string compare. Delivered as a relocatable linkable module in Microsoft format for use with FORTRAN-80 or COBOL- 80, etc SS3S/$23 □ KBASIC — Microsoft Disk Extended BASIC with all KISS facilities, integrated by implementation of nine additional commands in language. Package includes KISS.REL as described above, and a sample mail list program S995/S45 MICROPRO C^^ D Super-Sort I — Sort, merge, extract utility as absolute executable program or linkable module in Microsoft for- mat. Sorts fixed or variable records with data in binary, BCD, Packed Decimal, EBCDIC, ASCII, floating, fixed point, exponential, field justified, etc. etc. Even variable number of fields per record! $225/$25 □ Super-Sort II - only □ Super-Sort III — As II without SELECT/EXCLUDE $125/$25 D Word-Star — Menu driven visual word processing sys- tem for use with standard terminals. Text formatting per- formed on screen. Facilities for text paginate, page number, justify, center, underscore and PRINT. Edit facilities include global search and replace, read/write to other text files, block move, etc. Requires CRT terminal with addressable cursor positioning $445/$25 '/ Above available as absolute Drooram $175/$25 Software / with /Manual Manual/ Alone D Word-Master Text Editor — In one mode has super- set of CP/M's ED commands including global searching and replacing, forward and backwards in file. In video mode, provides full screen editor for users with serial addressable-cursor terminal $1 25 $25 SOFTWARE SYSTEMS □ CBASIC-2 Disk Extended BASIC — Non-interactive BASIC with pseudo-code compiler and runtime interpre- ter. Supports full file control, chaining, integer and ex- tended precision variables, etc $90/$15 "CP/M is a trade name of Digital Research * Z80 is a trademark of Zilog, Inc. "WHATSIT? is a trademark of Computer Head ware. tCP/M for Heath, TRS-80 Model I and PolyMorphic 8813 are modified and must use especially compiled versions of system and applications software, tfPolyMorphic 8813 CP/M scheduled for September 15 release. STRUCTURED SYSTEMS GROUP D General Ledger — Interactive and flexible system providing proof and report outputs. Customization of COA created interactively. Multiple branch accounting centers. Extensive checking performed at data entry for proof, COA correctness, etc. Journal entries may be batched prior to posting. Closing procedure automatically backs up input files. All reports can be tailored as necessary. Requires CBASIC $899/$25 □ Accounts Receivable — Open item system with output tor internal aged reports and customer-oriented statement and billing purposes. On-Line Enquiry permits information tor Customer Service and Credit depart- ments. Interface to General Ledger provided if both sys- tems used. Requires CBASIC $699/$25 D Accounts Payable — Provides aged statements of accounts by vendor with check writing for selected in- voices. Can be used alone or with General Ledger and/or with NAD. Requires CBASIC $699/$25 □ NAD Name and Address selection system — interactive mail list creation and maintenance program with output as lull reports with reference data or restricted informa- tion for mail labels. Transfer system for extraction and transfer of selected records to create new files. Requires CBASIC $79/$20 D QSORT — Fast sort/merge program for files with fixed record length, variable field length information. Up to five ascending or descending keys. Full back-up of input files created S95/S20 tRAHAM-DORIAN SOFTWARE YSTEMS D PAYROLL SYSTEM — Maintains employee master file. Computes payroll withholding for FICA, Federal and State taxes. Prints payroll register, checks, quarterly re- ports and W-2 forms. Can generate ad hoc reports and employee form letters with mail labels. Requires CBASIC. Supplied in source code $590/$35 □ APARTMENT MANAGEMENT SYSTEM - Fi- nancial management system for receipts and security deposits of apartment projects. Captures data on vacan- cies, revenues, etc. for annual trend analysis. Daily report shows late rents, vacancy notices, vacancies, income lost through vacancies, etc. Requires CBASIC. Supplied in source code $590 $35 Software for most popular 8080IZ80 computer disk systems including NORTH STAR, MICROPOUS, iCOM, DYNABYTE DB8I2, SD SYSTEMS, ALTAIR, EXIDY SORCERER, VECTOR MZ, 8" IBM, HEATH H17 & H89, HELIOS, IMSAI VDP42 & 44, REX, POLYMORPHIC 8813' and OHIO SCIENTIFIC formats. 90 BYTE September 1979 Software j with /Manual Manual/ Alone □ INVENTORY SYSTEM - Captures stock levels, costs, sources, sales, ages, turnover, markup, etc. Transaction information may be entered for reporting by salesman, type of sale, date of sale, etc. Reports avail- able both for accounting and decision making. Requires CBASIC. Supplied in source code $590/535. D CASH REGISTER — Maintains files on daily sales. Files data by sales person and item. Tracks sales, over- rings, refunds, payouts and total net deposits. Requires CBASIC. Supplied in source code 5590/535 MICRO FOCUS □ CIS COBOL — Version 3 is ANSI 74 subset with ex- tensions which offer powerful interactive screen format- ting and built in cursor control. Version 4 additionally oi- lers full level 1 ANSI for Nucleus, Table Handling, Se- quential Relative and Indexed I/O, Inter-Program Com- munication and Library Version 3, 5650/550 Version 4, S850/S50 □ FORMS — Interactive utility to create CIS COBOL source code to perform CRT screen handling in applica- tion programs. Supports full prompt text, protected fields and input validation against data type and range expected $1 50/$1 5 When purchased with CIS COBOL $125/515 OTHER D tiny C — Interactive interpretive system for teaching structured programming techniques. Manual includes full source listings $75/540 D C Compiler — Supports most major leatures of lan- guage, including Structures, Arrays, Pointers, recursive function evaluation, linkable with library to 8080 binary output. Lacks data initialization, long & float type and sta- tic & register class specifiers. Documentation includes "C" Programming Language book by Kernighan & Ritchie $1 10/515 □ ALGOL 60 Compiler — Powerful block-structured language featuring economical run time dynamic alloca- tion of memory. Very compact (24K total RAM) system implementing almost all Algol 60 report features plus many powerful extensions including string handling direct disk address I/O etc. Requires Z80 CPU . . . .$199/520 □ Z80 Development Package — Consists of: (1) disk file line editor, with global inter and intra-line facilities; (2) Z80 relocating assembler, Zilog/Mostek mnemonics, conditional assembly and cross reference table capabilities; (3) linking loader producing absolute Intel hex disk tile $95/$20 □ Z80 Debugger — Trace, break and examine registers with standard Zilog/Mostek mnemonic disassembly dis- plays. Facilities similar to DDT. $35 when ordered with Z80 Development Package $50/$1 D DISTEL — Disk based disassembler to Intel 8080 or TDL/Xitan Z80 source code, listing and cross reference files. Intel or TDL/Xitan pseudo ops optional. Runs on 8080 $65/$10 □ DISILOG - A DISINTEL to Zilog/Mostek mnemonic files. Runs on Z80 only $65/510 □ TEXTWRITER II — Text formatter to justify and pagi- nate letters and other documents. Special features in- clude insertion of text during execution from other disk files or console, permitting recipe documents to be created Irom linked fragments on other files. Ideal for contracts, manuals, etc. Also creates form letters in con- junction with a mail list file $75/510 □ TEXTWRITER III — All the features of TW II plus gen- eration of table of contents, sorted index and handling of footnotes. TW II users may upgrade for $60. $125/$10 □ WHATSIT?*** — Interactive data-base system using associative tags to retrieve information by subject. Hash- ing and random access used for fast response. Requires CBASIC $125/525 □ XYBASIC Interactive Process Control BASIC — Full disk BASIC leatures plus unique commands to handle bytes, rotate and shift, and to test and set bits. Available in Integer, Extended and ROMable versions. Integer Disk or Integer ROMable $295/525 Extended Disk or Extended ROMable 5395/525 Lifeboat Associates 2248 Broadway, N.Y., N.Y. 10024 (212)580-0082 Telex; 668-585 Software □ manual alone □ manual alone □ manual alone □ Check DU.P.S. COD □ Visa □ Master Charge Exp. Date Shipping $1.00 for C.O.D. Total Account # Signature My computer configuration (specifying di sk system): Name Address (No P.O. Box) City State Zip Price Orders must specify disk systems and formats: e.g. North Star single or double density, IBM single or 2D/256, Altair, Helios II, Micropolis Mod I or II, 614* soft sector (Micro iCOM/SD Systems Dynabyte), etc. Add $1/item shipping ($2 min.). Add $1 additional for UPS C.O.D. Manual cost applicable against price ol subsequent software purchase. The sale of each propriety software package conveys a license lor use on one system only. Software / with /Manual Manual/ Alone D SMAL/80 Structured Macro Assembled Language — Package of powerful general purpose text macro proc- essor and SMAL structured language compiler. SMAL is an assembler language with IF-THEN-ELSE, LOOP- REPEAT-WHILE, DO-END, BEGIN-END constructs 575/51 5 D Selector II — Data Base Processor to create and main- tain single Key data bases. Prints formatted, sorted re- ports with numerical summaries. Available for Microsoft and CBASIC (state which). Supplied in source code 5195/520 □ Selector III — Mufti (i.e., up to 24) Key version of Selec- tor II. Comes with applications programs including Sales Activity, Inventory, Payables, Receivables, Check Regis- ter, Expenses. Appointments, and Client/Patient. Re- quires CBASIC. Supplied in source code $295/520 Enhanced version for CBASIC-2 $345/520 □ CPM/374X Utility Package — Has full range of functions to create or re-name an IBM 3741 volume, dis- play directory information and edit the data set contents. Provides full file transfer facilities between 3741 volume data sets and CP/M files $195/510 D Flippy Disk Kit — Template and instructions to modify single sided 5V4" diskettes for use of second side in sin- gled sided drives $12.50 □ BASIC Comparison — A comprehensive features and performance analysis of five 8080 disk BASIC lan- guages — CBASIC, BASIC-E, XYBASIC, Microsoft Disk Extended BASIC, and Xitan's Disk BASIC. Itemizes re- sults of 21 different benchmark tests for speed and accu- racy and lists instructions and features of each BASIC (send 20? S.A.S.E.) FREE Lifeboat Associates 2248 Broadway New York, N.Y. 10024 "The Software Supermarket is a trademark ol Lifeboat Associates BYTE September 1979 91 Blubs and Newsletters Washington DC Computer Club The Washington Amateur Computer Society (WACS) is an organization dedicated to personal computing. They are organized to pro- vide a forum for the com- puter hobbyist and student of computing science. The Society meets on the last Friday of each month in the 1st floor lecture hall in Keane Hall on the campus of the Catholic University of America. The meetings start at 7:30 PM JWAC, the club's news- letter, is published for Socie- ty members and exchange with other hobby organi- zations. The newsletter is primarily an electronics journal. Annual dues have been set at $3.50 per year to cover the cost of 1st class postage for the journal and to defray the expenses of exchanging correspondence with other personal com- puting organizations. Non- members may subscribe to the journal at the rate of $5 per year. WACS is inter- ested in exchanging news- letters with other organiza- tions to further the inter- change of hobbyist infor- mation. Contact Washington Amateur Computer Society, c/o 4201 Massachusetts Ave, #168, Washington DC 20016. Cromemco User Systems and Software Pool Cromemco User, Systems and Software Pool is an HARD DISC FOR S100 MICROS The XCOMP DCF-10 Disc Controller pro- vides the OEM with a high performance, low.cost interface forfixed and removable (2315 or 5440) cartridge disc drives. The DCF-10 is currently supported by two operating systems. For information or manuals, contact XCOMP. XCOMP INCORPORATED 9915-A Businesspark Ave., San Diego, CA 92131 • (714) 271-8730 independent group for users of Cromemco computers. Board owners are also welcome. The purpose of CUssP is the exchange among users of Cromemco hardware and software of operating notes, bugs and their fixes, evaluation of hardware and software, user written software, and other announcements relating to Cromemco and associated products. The 1st volume of 3 newsletters included articles on changes in 16 K byte BASIC, CDOS I/O (input/- output) drivers, disk sectors and clusters, hardware modifications, etc. This volume is available for $10 in the US, Canada, and Mexico; and $12 in US funds for airmail delivery outside these regions. Membership with the 2nd volume is the same price as the 1st. There is also a special rate of 3 volumes (9 issues) for $25 in the US, Canada, and Mexico and $30 elsewhere. Contact Cromemco User, Systems and Software Pool, POB 784, Palo Alto CA 94302. Computer Graphics Letter Published by Harvard Readers of the new Har- vard Newsletter on Com- puter Graphics will be able to keep abreast of computer graphics in all its myriad ramifications. The newsletter monitors important commer- cial, technological, and pro- duct developments, as well as market, application, and learning opportunities. Among the regular depart- ments are News and Trends, Products, Markets, Applica- tions, R and D, Conferences and Seminars, Companies, Business and Financial, and State-of-the-Art Technology. The newsletter will be published twice a month. The content will encom- pass management and statis- tical graphics, computer graphic-aided design, engineering and manufac- turing, image processing, and automated cartography, plus other related areas. Trends in these areas, whether applied to big or small computers, stand- alone terminals, timesharing networks, users, vendors, will be followed. Readers will also learn where to ob- tain further information on the material covered. The subscription fee for 1 year is $125; a 9-issue trial subscription is available for $45. Airmail outside of North America is $19.50 for 1 year or $9.75 for the trial. Contact William Nisen, Har- vard University, Laboratory for Computer Graphics, 520 Gund Hall, Cambridge MA 02138. Akron Ohio Digital Group The Akron Digital Group meets on the 4th Wednesday of each month at 7 PM at the Kenmore Public Library, 2200 14th St SW, Akron OH. The club programs are aimed toward the small systems hobbyist with tips on programming and hard- ware application. Micro- processor classes are planned for the fall. Contact Lou Laurich, Akron Digital Group, 107 7th St NW, Barberton OH 44203. TRS-80 Publication Insiders: The TRS-80 Hardware Journal with Machine Software is a publication for any TRS-80 owner or user interested in more than BASIC. Both beginners and experts will find articles on machine 92 September 1979 © BYTE Publications lnc Circle 393 on inquiry card. language programming, hardware modifications, and other computer languages. Published since June of 1978, articles have described the differences in Level II read-only memories, how to get sound effects and music without a hardware modification, new languages for the TRS-80, and many other subjects. Regular features include a column which reviews various printers, the Disc File which covers the latest in DOS and compatible drives, a Dear Aunt TRiSh question and answer column, and learning machine language with Level II. A new section of the jour- nal will cover several of the new languages for the TRS-80. Future issues will include regular features on FORTRAN, FORTH, and other languages. Also, there will be regular articles on CP/M, reviews of various commercially available pro- grams, and more on both Level II and DOS. Subscriptions are available for 6 issues through Com- puter Cablevision, 2617 42nd St NW, Suite 2N, Washington DC 20007. New PET Users Group Forming in Washington and Oregon Individuals interested in forming a PET Users Group in the Oregon and Washington area should contact NW PET Users Group, c/o John F Jones, 2134 NE 45th Ave, Portland OR 97213. COSMAC Users Group Active Again After several unavoidable delays, the COSMAC Users Group is back in full opera- tion and The 1802 Peripheral newsletter is being published on a mon- thly basis. Information about the group may be obtained by writing to Patrick Kelly, Director, COSMAC Users Group, POB 7162, Los Angeles CA 90022. Please include a stamp with your inquiry. New Speechlab Users Group Formed Heuristics Inc, manufac- turer of Speechlab (a speech recognition unit for the Apple and all S-100 bus computers), has announced the formation of a users group. The users group requests that all interested Speechlab users send their unique uses of the hardware or software to Tom Larson, Director of Sales, Heuristics Inc, 900 N San Antonio Rd, Los Altos CA 94022. A directory of users and appli- cations will be published at a later date. Aim-65 Newsletter The Target is a bi- monthly newsletter for owners or prospective owners of Aim 65 systems. The subscription rate is $5 for 1 year. Contact Custom- Tronics, POB 4310, Flint MI 48504. Solano TRS-80 Users Club The Solano TRS-80 Users Club is an informal group that gets together to discuss mutual problems and exper- iences. Their meetings are held every 3rd Thursday starting July 5th at Owens- Illinois, 2500 Huntington Dr, Fairfield CA. Contact Dave or Steve Irwin, 550 Marigold Dr, Fairfield CA 94533, or call (707) 422-3347. The Tulsa Computer Society The Tulsa Computer Society meets the last Tues- day of every month at 7:30 PM. The meeting place is the Tulsa Vocational- Technical School seminar room at 3420 South Memorial Dr (behind Edison's Department Store). Membership in TCS is $6 annually and includes a 1 year subscription to the club's newsletter, The I/O Port. Contact The Tulsa Computer Society, POB 1133, Tulsa OK 74101. Wichita Valley TRS-80 Users Group Sustains Computer Loss in Recent Tornado In the recent tornado which wreaked unholy havoc on our city, many of us in the Wichita Valley TRS-80 Users Group lost our computers, our tape and disk library of software, and our library of computer books and periodicals. Even our club's library of soft- ware and publications was destroyed. We all have plans to replace our personal com- puters and software, but at this time I am particularly interested in trying to help our club replace its loss. Any club, publisher, soft- ware producer, or individual who wishes to do so, may contribute noncash items, such as software, back issues of computer publications, and books on computers. Our address is the Wichita Valley TRS-80 Users Group, POB 4391, Wichita Falls TX 76308. Thank -you, our club will be grateful. J Wesley B Taylor Club Secretary Although this letter cer- tainly speaks for itself, it is our sincere hope that you or your group will seriously consider contributing non- cash computer related items to this needy organization.* computer mart of new jersey computer mort of Pennsylvania the microcomputer people® Computers don't moke a computer store, PEOPLE do. Our people hove been involved with microcomputers since day one. We offer experience and expertise unparalleled in the microcomputer industry. Whether you are in the market for o complete system, peripherals, custom software, service, or just some friendly advice; there simply is no other place to go. Computer Mart of Now Jonoy 501 Rout* 27 iMlln. NJ 08800 (201) 280-0600 STOKE HOURS Tum. - Sat. 1 0am - 6p Tuai. Thun. 'till 9p CLOSED MONDAYS Computar Mart of P»nnjy Ivor 330 DoKalb Pill* King of Prussia, PA 19406 (213) 263-2380 Circle 66 on inquiry card. September 1979 © BYTE Publications Inc 93 ^MINIMAX C 0MP U "FULLY INTEGRATED COMPUTER SYSTEM" MINIMAX SERIES COMPUTER THE MINIMAX SERIES WAS DESIGNED TO OFFER THE MARKET MINICOMPUTER CAPABILITIES AT MICROCOMPUTER PRICES. COMPARE THE CAPABILITIES & PRICE! CONTACT NEECO FOR FULL SPECS - FREE MINIMAX MANUAL. MEET THE MINIMAX COMPUTER THE MINIMAX SERIES computer was designed by industry professionals. frfffV KsKJ COMPARE THE PRICE AND FEATURES TO ANY OTHER COMPUTER IN ITS CLASSI MINIMAX I - .8 MEGABYTE ON LINE MINIFLOPPY STORAGE MINIMAX II - 2.4 MEGABYTE ON LINE 8" FLOPPY STORAGE MINIMAX I - MINIMAX II - $4495 $5995 •THE MINI MAX SERIES COMPUTER IS AN INTEGRATED. COMPACT UNIT CONTAINING THE CPU. DUAL DENSITY DISK STORAGE. 12 INCH CRT, AND FULL STYLE KEYBOARD, WITH SEPARATE NUMERIC ENTRY PAD. ALL KEYS (INCLUDING CURSOR) WITH FULL REPEAT • HYBRID 2 MEGAHERTZ 6502 CPU • 108K SYSTEM RAM (48K USER) • FASTEST FLOPPY DISK ACCESS (24K LOADS IN 4.2 SECONDS) • 16K ROM CONTAINS COMPUTHINK BASIC (AN EXTENDED MICROSOFT BASIC) WITH EXTENDED PRECISION, DOS INCLUDES COMPLETE FILE I/O WITH FULL RANDOM ACCESS, COMPLETE MONITOR WITH DEBUG & TRACE, AND TINY 6502 ASSEMBLER • COMPLETE HIGH RESOLUTION GRAPHICS WITH INDIVIDUAL DOT (240x512) POINT SCREEN ADDRESSABILITY • FULL SCREEN TEXT EDITING WITH OVERWRITE. INSERTION OR DELETION • SPLIT SCREEN/WINDOW MODES • INDIVIDUAL FIELD EDITING WITH FIELD PROTECT AND AUTO SKIP TO NEXT FIELD • DISK STORAGE SYSTEM TRANSFERS 6K PER SECOND WITH AUTO VERIFY AND PARITY CHECK • 12 INCH CRT-64 CHARACTERS BY 30 LINES. UP TO THREE PROGRAMMABLE CHARACTER FONTS FOR LANGUAGES OR SPECIAL CHARACTERS • • • SWITCHABLE 1 10 OR 220V OPERATION • • • • HYBRID CPU IS MICROPROGRAMMABLE WITH 64 USER DEFINABLE OPCODES. CHOICE OF 800K OR 2.4 MEGABYTE DISK STORAGE • FULL SERIAL RS-232C PORT WITH PROGRAMMABLE BAUD RATES AND MODEM CONTROL SIGNAL • DEDICATED DISK PORT • PRINTER PORT SUPPORTS PARALLEL COMMERCIAL PRINTERS • 24 PIN I/O USER PORT • PAGEMATE DATABASE AVAILABLE • PLM COMPILER AVAILABLE • BUSINESS PACKAGES AVAILABLE • COMPLETE DIAGNOSTICS & SCHEMATICS INCLUDED • COMPLETE USER MANUAL INCLUDED SPECIAL DEALER PRICING AVAILABLE ON DEMONSTRATION MINIMAX AND SOFTWARE PACKAGES TO QUALIFIED SELECTED DEALERS. CONTACT NEECO FOR INFO. PRINTER NOT INCLUDED IN PRICE THE MINIMAX WAS DESIGNED AND IS MANUFACTURED BY COMPUTHINK COMPUTER CORP. DISTRIBUTED IN EUROPE AND THE EASTERN U.S. BY NEECO. IN ADDITION TO HARDWARECAPABILITIES THAT ARE UNMATCHED IN THE INDUSTRY, THE MINIMAX COMPUTER SUPPORTS A COMPLETE DATA BASE SYSTEM (PAGEMATE), CONTAINING FULL STATISTICAL, SORTING, AND EDIT FUNCTIONS. A PLM COMPILER IS AVAILABLE, FULL BUSINESS SUPPORT SOFTWARE IS AVAILABLE AND MORE!— FULL DEALER SUPPORT IS AN IMPORTANT PART OF OUR MARKETING. CONTACT NEECO FOR FURTHER INFORMATION. THE MINIMAX IS NOW AVAILABLE FOR QUANTITY DELIVERY. DOMESTIC DEALERSHIPS AVAILABLE. EUROPEAN DISTRIBUTORSHIPS/DEALERSHIPS AVAILABLE TO QUALIFYING COMPANIES WITH SUPPORT CAPABILITIES. SOFTWARE HOUSES AND OEM INQUIRIES INVITED. CONTACT NEECO. NEECO NEW ENGLAND ELECTRONICS CO., INC. 679 HIGHLAND AVE., NEEDHAM, MA 02194 MON-FRI, 9:00-5:30, E.S.T. (617)449-1760 TELEX 951021, ANSWERBACK "NEECO' 94 BYTE September 1979 Circle 281 on inquiry card. NEECO PET 2001 — 32K PROUDLY ANNOUNCES THE NEWEST PET MICROCOMPUTERS BY COMMODORE! The PET™ is now a truly sophisticated Business System with the announcement of these Peripherals. "he PET'", incwjiar.-ilml -.v-th ine I tunny D.sk air] Printer makm an ideal Business system for most crotessronai and sfiuciatoct Mils medicine taw, denial resesrcti tnginaering loolmaking. ptintmc; education, energy cnn sorvaien, etc The PET™ Business System as a n!ati,i(jf;mGnr io:;1 (tolivL'rs >ntar million 10 all levels of Business previously aiid'iiaUie only win cquipmeni nany limosmoicc(X;nsi«e Tun PET 1 * Business System is ore Of Ine most cost OfftOOrt Dusness ion's lixi.iy it offers ci '.'jiiI' 1 r.iniii: ot ;jr,)pi.i-;ikKis tram logging m;ina;iei'n(ir,t si(,iii>(iy in major rcGrpcrationsioarrjiirionii accounts and inventory control of small DuS'nessf.'ij Here are |usl a tew ot Hie cost- saving uses in ihe cO'poratinn prolessionai office 01 small business slock connol purchasing. irj:e(:.-isliiH| manuiadiiring costing. customer records, mailing hsls. etc The PET ". Floppy Disk and Punier a comoatiDie business system at a reasonable p/ice — Take a closer too-! at mese Fcrinne-ais LARGE TYPEWRITER KEYBOARDS NOW AVAILABLE! PRODUCT DESCRIPTION PET 2001— 4K 4K RAM PET 2001— 8K 8K RAM PET 2001 — 16KN (Large Keys)16K RAM* PET 2001— 32KN (Large Keys)32K RAM PET 2023 PRINTER PET 2022 PRINTER PET 2040A PET 2040 PET C2N ROLL FEED TRACTOR/ROLL SINGLE FLOPPY DUAL FLOPPY* 2nd Cassette "The 16K/32K (large keyboard) units do not include a cassette drive. Order C2N Cassette 2040 Floppy Drive requires a 16K or 32K unit. 8K RAM Retrofit available July. PRICE $ 595 $ 795 $ 995 $1295 $ 850 $ 995 $ 895 $1295 $ 100 AVAILABILITY IMMEDIATE IMMEDIATE IMMEDIATE IMMEDIATE IMMEDIATE IMMEDIATE JUNE/JULY IMMEDIATE IMMEDIATE ALL UNITS ARE FULLY TESTED BYNEECO BEFORESHIPMENT. ALL PET'S ARE WARRANTEED (BY NEECO) FOR 1 FULL YEAR! NEECO IS A FULL CUSTOMER- ORIENTED BUSINESS. PLEASE CALL FOR ADDITIONAL INFORMATION. ALL UNITS ARE IN STOCK & READY TO SHIP. FULL SOFTWARE AVAILABLE! FOR 8K PETS (small keyboards) .4 Megabytes of Disk Storage for8K PETS! (Requires Expandamem) 400K-8S DISK SYSTEM INCLUDES RANDOM ACCESS IN DOS-LOADS 20K IN 4 SECONDS! 24K Expandamem Memory -525 $W QQC 32K Er.pandamem Memory : -615 I fa*/ J COMPUTHINK .4 & .8 MEGABYTE DISK DRIVES FOR THE NEW 16/32K PETS! DISK SYSTEMS INCLUDE DISKMON OPERATING SYSTEM IN ROM AND INTERFACE TO 16/32 PETS! Dual Minifloppy Drives with 200K per diskette side for total 4O0K/80OK on line. 800K model accesses all 4 diskette sides via dual read and write arm system Dual Dens'ty Hardware and DOS loads 20K (with verification) in 4 2 seconds complete DISKMON (DOS) adds 17 commands to BASIC including Random Access and printer support 1 System comes complete wilh plug in internal board containing 8K RAM. 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BYTE September 1979 95 The Nature of Robots Part 4: Looking for Controlled Variables William T Powers 1138 Whitfield Rd Northbrook IL 60062 In this last part of my series of articles, a simple experiment with a human subject will be attempted; an experiment that can be expanded almost indefinitely. All of the prin- ciples from the previous parts will be used. Before the experiment starts, note the following main points that have been established: • The behavior of an organism is not its output, but some consequence of its motor outputs acting together with unpredictable forces or other disturbances. • For a more or less remote conse- quence of motor outputs to be repeatable in a disturbance-prone world, the behaving system must sense the consequence, and act to keep it matching some static or dynamic reference condition. By definition, that makes the organism a control system. • Organisms acting as control systems control what they sense, not what they do. • What is controlled is what is sensed, even when the sensing in- volves one or more stages of real- time computations based on primitive sensory signals. • In a multiple-level control system, the higher levels act by varying the reference signals for lower-level systems. They control perceptions computed from many lower-level perceptions, some or all of which are controlled by the same lower- level systems. • If there are n degrees of freedom at one level of control, in principle n higher-level systems could act in- dependently and simultaneously by sharing the use of the lower- level systems. Any higher-level system acts by sending amplified copies of its error signal to many lower-level systems, each with the proper sign to achieve a negative feedback effect. Any lower-level system receives a reference signal that is the net effect of super- imposed higher-level output signals. This worked for a 2-level system with 3 control systems at each level; there is no limit, in principle, to the number of levels or the number of systems at each level. In practice, there is reason to anticipate finding hundreds of systems at a given level, but no more than 10 or 12 distinct levels in a human being. This will be commented on later. Abstract models and simulations are fine for conveying general ideas. However, if one does nothing but make models and simulations, it is easy to get involved in the math and engineering, and forget the real thing is there to be seen. Items described in the first 3 articles in this series repre- sent something real. Real organisms work much the same way control systems work. They do not work in any of the other ways that have been proposed over the centuries (as far as their behavior is concerned). I am not talking metaphorically. There are ex- cellent reasons to think that when the properties of organisms begin to be investigated in terms of control theory, hard data about the way we are organized will start to accumulate (up to a point, anyway). The experiment to be described in this article is so simple that it may look elementary. Nevertheless, it is the starting point for a new approach to exploring the organization of human beings. Most new ideas start by looking like old ones, but with a twist that leads in unexpected direc- tions. If you are familiar with track- ing experiments, do not be too quick to decide what this is all about. Equipment Required The basic equipment needed to do this experiment is: • A joystick with 1 degree of freedom (ie: a potentiometer with a stick on the shaft will suffice). • A reasonably fast analog-to-digital (A/D) converter with 7-bit or more accuracy. My system uses the Cromemco D + 7A, which has 7 analog channels in and 7 out, as well as 1 input and 1 output 8-bit port. • A memory-mapped display, in which points are plotted on a video screen by depositing appropriate codes in a reserved segment of memory. This, or something equivalent, is essential for creating the moving objects that are involv- ed in the experiment. I use the Polymorphics VTI with the display area in the 1 K bytes of memory starting at hexadecimal location D000. Out of deference to systems that do not have the VTI's graphics capability (however crude), I have used 64 horizontal elements in the alphabetic mode. Higher resolu- tion would be much more desir- able, but this much is enough to show the principles well. If no memory-mapped display is available, but 2 digital-to-analog (D/A) outputs and a triggered oscilloscope are, the display that is needed can be created. Use 1 D/A 96 Seplember 1979 © BYTE Publications Inc onComputing really makes personal computers easy to under- stand." Written in non-technical language, onComputing™ contains articles on the capabilities of microcomputers, getting started, latest reviews of personal com- puters, where to purchase and how to use your computer. Aas xyone can learn the funda- mentals of using a computer. onComputing readers receive practical advice and helpful hints on how to get the most out of a personal computer, explanations of computer terminology, and, periodically, an updated list of active computer clubs. XJenefit from the experience of other computer enthusiasts. Articles in onComputing are written by well known authors as well as competent amateurs. They share their ideas on how to use the computer as a tool for business, education, home enter- tainment, laboratory work and other applications. r Vfomputer experts edit onCom- puting for the new user, not the computer professional. The editors combine their esoteric knowledge of computer science and equipment to produce con- cise, non-technical material which can be readily understood by anyone interested in using a computer— for fun or profit. I onComputing, Inc. 70 MainSt., Peterborough, NH03458 Start your subscription today. EVERY THREE MONTHS onComputing will bring the latest develop- ments in the field of personal computing: use, applications, books, selection— all in an easy-to-read style. 1 onComputing, Inc. 1979 onComputing Subscription Dept. P.O. Box 307, Martinsville, NJ 08836 REGULAR subscription rate: □ U.S. 1 yr. (4 issues) @ $8.50 □ Canada & Mexico, 1 yr. (4 issues) @ $10.00 FOREIGN (to expedite service, please remit in U.S. funds drawn on a U.S. bank.) □ Europe (and all other countries, except above), lyr.@ $18.00— surface delivery. D Start my subscription with current issue. □ Start with Vol. 1 No. 1 □ Bill Visa □ Bill Master Charge D Bill me (North America only) Card Number Expiration Signature Name (please print) Street/Apartment Number City State/Province/Country Code L. 7M89 BYTE September 1979 97 converter to deflect the trace in the Y direction, and the other (or 1 bit of a digital port) to trigger the sweep. By starting the sweep and then out- putting the 3 cursor values in se- quence, a 3-segment trace can be created, with the motion of the cur- sors being up-and-down instead of side-to-side, as in the following pro- gram. Lay the oscilloscope on its side if that deviation bothers you. Systems with built-in graphics under BASIC control, such as Apple, PET, or TRS-80, will probably allow the experiment to be done more simply than how I did it in listing 5. The basic requirement is to be able to read a number from a stored table, add the handle position to it, erase the old cursor, and use the sum to position the new cursor, doing this for 3 cursors at least 4 times per se- cond - the faster the better. (An exam- ple of the simulation on the Apple II is shown in listing 6.) Experimental Design Imagine a display with 3 cursors on it, one above the other. Each cursor can move left and right. The subject looks at this display while holding a control handle. The instructions for the first experiment are very simple: the subject is asked to select 1 of the cursors, and hold it still, somewhere near the center of the screen as ac- curately as possible for the duration North Star Strings The North Star BASIC string expression B$(I,J) corresponds to MID$ (B$,IJ) in other versions of BASIC. B$(I) corresponds to RICHT$(B$,I), and B$(1,I) corresponds to LEFT$(B$,1,I). of the run. Engineering psychologists call this "compensatory tracking." They use it to investigate the limits of speed and accuracy of control in the presence of rapid disturbances of various kinds. If the handle is held centered, each cursor will be seen to wander back and forth in a pattern that is indepen- dent of the other 2 cursors. In this ex- periment, the disturbances causing this wandering are made very slow and smooth. With even a slight amount of practice, every subject will be able to maintain essentially perfect control. Transfer functions will not be measured, nor will the limits of control be tested in the manner tradi- tional in engineering psychology. A subject acting well within the range of normal operations under conditions where the phenomena of control can be clearly seen is desired. The subject selects a visual variable (position of 1 of the cursors), selects a reference level for that variable (a particular position), and maintains the perceiv- ed position at the reference position, while disturbances act that tend to move the cursor away from the reference position. Figure 17 shows the setup in schematic form. The 3 disturbances are labeled Dl, D2, and D3. The 3 cursor positions are labeled Cl, C2, and C3. The position of the control handle is H. The position of each cur- sor is determined by the sum of H and one of the Ds. For cursor 2 the effect of the handle is reversed, so the 3 relationships are: Cl C2 C3 Dl + H D2 - H D3 + H If the subject controls C3 in rela- tion to a reference position of (ie: midscreen), and does so perfectly, then = D3 + H, or H=-D3. The handle position should be an accurate mirror image of the magnitude of the disturbance D3 at every moment, and the cursor C3 does not move at all. You will find that all subjects, after a little practice, will closely approx- imate these predictions. This may seem elementary, ob- vious, boring and hardly worth the labor of getting the experiment up and running. Do not be deceived; this experiment appears to be simple because it is fundamental. It is fun- damental because it can prove that all of the life sciences have been using the wrong model. There are also several extensions of the experiment that will show how to get started mapping the whole hierarchy of human control systems. There is no theory and no simulation that carries the impact of seeing how a real living control system works; especially when you can understand every detail of what is happening, either as subject or observer. The 3 previous articles in this series have been designed to give the ability to grasp what is happening here. This experiment is designed to give the gut feeling of knowing. Program Structure The program in listing 5 is written in North Star BASIC, Version 6, Release 3. It contains a machine- language subroutine for an 8080/Z80 Text continued on page 102 Figure, table, and listing numbering continued from part 3. Z=RMD(A/100) Listing 5: North Star BASIC control-variable simulation. The necessary assembly language routines needed for execution are also given. 10 DIM H$(16),D1$(250),D2$(250),D3$(250),H1$(250),F$<82),S$(82) 20 DIM A$(2) 30 H$="0123456789ABCDEF" 40 INPUT "SEED FOR RANDOM GENERATOR (1 - 100) ",A\ 50 REM ******************************* 60 REM CONVERT 2 HEX DIGITS TO DECIMAL 70 REM ******************************* 80 DEF FNB(AS) 90 U=ASC(A$(1,1))\IF U<58 THEN U=U-48 ELSE U=U-55 100 V=ASC(A$(2,2))\IF V<58 THEN V=V-48 ELSE V=V-55 110 120 RETURN FNEND 16*U+V 98 September 1979 © BYTE Publications Inc 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270 280 290 300 310 320 330 340 350 360 370 380 390 400 410 420 430 440 450 460 470 480 490 500 510 520 530 540 550 560 570 580 590 600 610 620 630 640 650 660 670 680 690 REM REM REM INPUT GOSUB !"6 S M1 = 25 DATA DATA DATA DATA M = M1 READ FILL REM REM REM FILL FILL FILL FILL REM REM REM INPUT GOSUB FILL FILL REM REM REM W = 3*3 \! "T "T \P "F *********************************** SET MACHINE-LANGUAGE PROGRAM ORIGIN *********************************** "MOST SIG. BYTE, SUBROUTINE LOCATION: ",SS 1130 EC TO LOAD SUBROUTINE" 6*A0\ M2=Ml+9 " 02 00000000000000004BDB 19071 F1 F4 73A0800FE00C21 C00782F" "3C477881E63F4F2A00003A08003C3CFE0 6DA2F00AF" "320800856F5E23563EA0127BE6C0B15F3EAA12722B73DB19EE80" "6F2600C9" !\ !\ !\ !\ !\ ! \ N1=32 FOR J D1SCJ D3$(J NEXT i » N3^25 IF J- R1 = R1 NEXT INPUT FOR J REM REM REM ! \! \! GOTO FOR I FILL B$\FOR M,A\ M ***** INSER ***** M1+1,A M1+FNB M1+FNB M1+FNB ***** SET L ***** "MOST 1130 M1+2,F M1+6,F ***** LOAD ***** .14159 A!\!\ HE SCR HEN TH ICK ON OR THE \ N2=3 = 1 TO ,J)=CH ,J)=CH J CLOA \FOR J N3*INT +CRO-R J "READY = 1 TO ***** EXPER ***** \GOSUB 690 = 1 TO M 1+8,4 J = 1 TO LEN(B$)-1 STEP 2\ A= FNB (BS ( J , J + 1 ) ) = M + 1\NEXT J\ IF AO201 THEN 250 ****************** T RELOCATION BYTES ****************** 0\ FILL M1+FNB("12"),A0 ("17"),A0\ FILL M1+FNB("23"),A0 ("2D"),A0 ("26"),A0\ FILL M1+FNB("31"),A0 ******************** OCATIONS FOR DISPLAY ******************** SIG. BYTE, DISPLAY LOCATION: ",S$ NB("CO")\ FILL M1+3,A0\ FILL M1+5,A0+2 NB("40")\ FILL M1+7,A0+3 ****************** DISTURBANCE TABLES ****************** 27/250\R0=RND(0)\Rl=32*R2=Rl CONE MINUTE TO LOAD DISTURBANCE EEN WILL CLEAR AND THREE REE CURSORS WILL APPEAR, E CURSOR AND TRY TO HOLD DURATION OF THE RUN, AS CSTAND BY FOR PROMPT]" 1\ N3=25\ N4=64\ N5=10 250 R$(N1+N2*SIN(W*J) ) R$(64-ABS(J-125)/2) DING RANDOM DISTURBANCE: STAND BY]" =1 TO 250 (J/N3)=Q THEN R0=N4*RND(0) 1)/N5\ R2=R2+(R1-R2)/N5\ D2$ ( J , J ) =C HR$ CR2 ) TO GO: HIT RETURN TO PROCEED. ",A$ 16\! \NEXT *********** IMENTAL RUN *********** 680\! \!\!\!AGOSUE 680\ ! \ ! \ ! \ ! \GOSUP 6R0\!\! 8\! "TTTTTTT+",\NEXT I\ RETURN \ REM SYNCH CURSOR COUNTER tables:" scales will appear." one for each scale." it in one position" exactly as you can." Listing 5 continued on next page September 1979 © BYTE Publications Inc 99 700 N1=8\N2=127\N3=128\ FOR J=1 TO 250 710 FOR L=1 TO 4 720 OUT 25,N2\ OUT 26, N3 730 H=CALL(M2,ASC(D1$(J,J))) 740 H=CALL(M2,ASC(D2S(J,J))) 750 H=CALL(M2,ASC(D3$(J,J))) 760 NEXT L 770 H1$(J / J)=CHR$(H) 780 NEXT J 790 REM ********************* 800 REM DATA PLOTTING PROGRAM 810 REM ********************* 820 GOSUB 1050\ IF Y0<1 THEN 560 830 !"AFTER PLOT, HIT RETURN TO CONTINUE" 840 INPUT"WHICH CURSOR (1,2,3)? ",I 850 IF 1=0 THEN 560 860 FOR W=1 TO 250 STEP INT (250/ CYO+1 ) ) 870 H=(ASC(H1$(W,W))-128)*X0/128 880 ON I GOTO 890,900,910 890 V=ASC(D1$(W,W) )-32\ GOTO 920 900 V=ASC(D2$(W,W))-32\ H=-H\ GOTO 920 910 V=ASC(D3$(W,W))-32 920 V=V*X0/64+1 930 C=V+H+ZO\ IF C<1 THEN C=1\ IF OXO THEN C=XO 940 V=V+ZO\IF V<1 THEN V=1\ IF V>XO THEN V=XO 950 H=H+ZO\ IF H<1 THEN H=1\ IF H>XO THEN H=XO 960 B$=S$\B$(ZO,ZO)="." 970 !#TO,\B£(V,V)="D"\ B$(H,H)="H"\ B$(C,C)="C" 980 U=0\ IF V>U THEN U=V\IF H>U THEN U=H\IF OU THEN U=C 990 IF ZO>U THEN U=ZO\B$=B$ (1 ,U) \ !#TO,P$, 1000 NEXT W 1010 INPUT1"",A$\ GOTO 820 1020 REM ******************************** 1030 REM SET UP FOR PLOTTING (SUBROUTINE) 1040 REM ******************************** 1050 !\INPUT "Y-DIMEflSION OF PLOT (0 = NEW RUN): ",Y0\ Y0 = Y0-2 1060 IF Y0<1 THEN RETURN 1070 INPUT "X-DIMENSION OF PLOT (1-72): ",X0 1080 IF X0>72 THEN 1070\ IF X0<1 THEN 1070\X0=X0-2 1090 INPUT "OUTPUT DEVICE (T OR S)",A$ 1100 IF A$="T" THEN T0=2 ELSE T0=0 1110 SS = ,,M \FOR 1 = 1 TO XO\S$ = S$ + " "\ NEXT I 1120 Z0=INT(X0/2)\ RETURN 1130 REM ********************************** 1140 REM CONVERT HEX IN S$ TO DECIMAL IN AO 1150 REM ********************************** 1160 A0=0\K = 1\F0R J = 1 TO LEN (S$ )-1 \K = K*1 6\MEXT J \K = INT (K + . 01 ) 1170 FOR I = 1 TO LEN(S$) 1180 FOR J=1 TO 16 1190 IF S$(I,I)=H$(J,J) THEN EXIT 1220 1200 NEXT J 1210 !"NOT HEX NUMBER"\ EXIT 160 1220 AO = AO + K*(J-1)\ K=K/16 1230 NEXT I 1240 RETURN 1250 REM ******************************* 1260 REM UTILITY, CONVERT HEX TO DECIMAL 1270 REM UP TO TEN HEXADECIMAL DIGITS 1280 REM DO "RUN 1300" 100 September 1979 © BYTE Publications Inc 1290 REM ******************************* 1300 DIM HS(16)\H$="0123456789ABCDEF"\! 1310 INPUT1"HEX= ",S$\G0SUB 1160\!" DECIflAL= ",A0\GOTO 1310 001 * MACHINE LANGUAGE 002 * 003 ORG 004 * 005 0000 0200 ADRO DBL ADR1 006 0002 0000 ADR1 DBL 007 0004 0000 ADR2 DBL 008 0006 0000 ADR3 DBL 009 0008 00 COUNT DATA 010 0009 4B START MOV C,E 011 OOOA DB19 IN 25 012 OOOC 071F1F ARS 013 OOOF 47 MOV B,A 014 0010 3A0800 LDA COUNT 015 0013 FE02 CPI 2 016 0015 C21C00 JNE S1 017 0018 78 MOV A,B 018 0019 2F CMA 019 001A 3C INR A 020 001B 47 MOV B,A 021 001C 78 S1 MOV A,B 022 001D 81 ADD C 023 001E E63F ANI :3F 024 0020 4F MOV C,A 025 0021 2A0000 LHLD ADRO 026 0024 3A0800 LDA COUNT 027 0027 3C INR A 028 0028 3C INR A 029 0029 FE06 CPI 6 030 002B DA2F00 JLS S2 031 002E AF ZAR 032 002F 320800 S2 STA COUNT 033 0032 85 ADD L 034 0033 6F MOV L,A 035 0034 5E MOV E # M 036 0035 23 INX H 037 0036 56 MOV D / M 038 0037 3EA0 MVI A,:AO 039 0039 12 STAX D 040 003A 7B MOV A,E 041 003B E6C0 ANI :C0 042 003D B1 ORA C 043 003E 5F MOV E,A 044 003F 3EAA MVI A,:AA 045 0041 12 STAX D 046 0042 72 MOV M,D 047 0043 2B DCX H 048 0044 73 MOV M,E 049 0045 DB19 IN 25 050 0047 EE80 XRI :80 051 0049 6F MOV L,A 052 004A 2600 MVI H,0 053 004C C9 RET SUPPORT ROUTINES GET HANDLE DIVIDE BY TWO SAVE IN B CHECK FOR MIDDLE ONE IF MIDDLE ONE NEXT, MAKE HANDLE NEG. (TWO'S COMPL.) X=X+HANDLE LIMIT TO 63 SAVE X IN C GET BASE ADDRESS GET DISPLACEMENT BUMP TWICE CHECK MODULO 6 MAKE ADDRESS FOR CURRENT CURSOR. DE=OLD SCREEN ADR. LOAD A SPACE ERASE OLD CURSOR ZERO DISPLACEMENT NEW DISPLACEMENT POINTER FIXED LOAD ASTERISK CURSOR PUT IT ON SCREEN SAVE CURSOR ADDRESS GET HANDLE AGAIN RANGE 0-255 September 1979 © BYTE Publications Inc 101 5 HIMEM: 8192 10 DIM D1 %(250),D2%(250),D3%(250),H1 %(250) 20 INPUT "SEED (0-100): ";A 30 Z = RND(A/ 100) 40 REM LOAD DISTURBANCE TABLES 50 W = 3 . 3.141592654 / 250 60 R0 = RND(0):R1 = R2 = 140 65 PRINT : PRINT : PRINT : PRINT : PRINT : PRINT : PRINT : PRINT 70 PRINT : PRINT : PRINT "LOADING DISTURBANCE TABLES" 75 PRINT 80 PRINT "WHEN SCREEN CLEARS, BACKROUND WILL" 85 PRINT 90 PRINT "APPEAR — THEN THREE CURSORS." 95 PRINT 100 PRINT "PICK ONE CURSOR AND HOLD IT IN" 105 PRINT 110 PRINT "ONE POSITION FOR THE DURATION OF" 115 PRINT 120 PRINT "RUN, AS ACCURATELY AS YOU CAN- 125 PRINT 130 PRINT "STAND BY FOR PROMPT MESSAGE" 140 FOR J = 1 TO 250 150 D1%(J) = 140 + 130 * SIN (W , J) 160 D3%(J) = (125 - ABS (J • 125)) . 270 / 125 170 NEXT J 175 PRINT 180 PRINT "RANDOM DISTURBANCE LOADING: STAND BYE." 185 N3 = 25:R1 = 140:R2 = 140 190 FOR J = 1 TO 250 200 N3 = N3- 1: IF N3 > THEN 210 205 N3 = 25:R0 = 280 . RND (5) 210 R1 = R1 + (R0 ■ R1) / 05:R2 = R2 + (R1 - R2) / 5 220 D2%(J) = R2 230 NEXT J 240 PRINT : INPUT "HIT RETURN FOR RUN";A$ 250 HGR 255 HCOLOR= 3 260 POKE 49234, 261 FORX = 1 TO 280 STEP 10 262 FOR Y = 43 to 143 STEP 50 263 HPLOTX.Y: HPLOT X,Y 4- 14 264 NEXT Y: NEXT X 270 FOR J = 1 TO 250 280 FOR K = 1 TO 4 290 H = PDL(0)- 128 299 HCOLOR = 0: HPLOT C1 % , 45 TO C1 % ,55: HCOLOR = 3 300 C1% = D1%(J) + H 305 IF C1% < 0THEN C1% = 306 IF C1 % > 279 THEN C1 % = 279 307 HPLOT C1 %,45 TO C1 %,55 309 HCOLOR= 0: HPLOT C2%,95 TO C2%,105: HCOLOR= 3 310 C2% = D2%(J)- H 315 IF C2% < 0THEN C2% = 316 IF C2% > 279 THEN C2% = 279 317 HPLOT C2%,95 TO C2%,105 319 HCOLOR = 0: HPLOT C3%, 145 TO C33%, 155: HCOLOR = 3 320 C3% = D3%(J) + H 325 IFC3% < 0THENC% = 326 IFC3% > 279 THEN C3% = 279 327 H PLOT C3 % , 1 45 TO C3 % , 1 55 370 NEXTK 380 H1%(J) = H 390 NEXT J 400 HGR 405 POKE 49234, 410 FOR J = 1 TO 250 420 Y = 191 - J * 191 /250 430 U = 88 / 280 435 H = INT (H1 %(J) , U) 440 D1 = INT((D1%(J)- 140) . U + 45) 450 D2 = INT (D2% J) - 140) * U + 135) 460 D3 = INT((D3%(J) - 140) . U + 225) 461 C1 = D1 + H:C2 = D2 - H:C3 = D3 + H 462 IFC1 < 0THEN C1 = 463 IF C3 > 278 THEN C3 = 278 480 HCOLOR = 1 490 HPLOT D1,Y: HPLOT D2,Y: HPLOT D3,Y 500 HCOLOR = 2 510 HPLOT C1 ,Y: HPLOT C2,Y: HPLOT C3,Y 520 HCOLOR = 3 530 HPLOT H + 45, Y: HPLOT ■ H + 135, Y: HPLOT H +225.Y 540 NEXT J 550 INPUT "";A$ 560 TEXT 570 GOTO 180 Listing 6: A computer such as the Apple II which has high-resolution graphics capa- bilities greatly simplifies the program originally given in listing 5. This program performs the same operations as the simu- lation in listing 5. The author acknow- ledges the assistance of Charles Faso from Computerland of Niles IL in preparing this program. Text continued from page 98: processor which is loaded by the BASIC program at any specified 256-byte memory-address boundary (specify in hexadecimal only the most significant byte of the location of the subroutine). The machine-language subroutine reads in the handle position, adds it with the appropriate sign to the value of a disturbance that is passed to the subroutine by the CALL command (in the DE register pair), erases the old cursor, and deposits the new cur- sor, a rubout, on the screen. Each time the subroutine is called it steps to the next cursor, recycling as necessary. On return from the subroutine, the handle position is passed back to the main program (in the HL registers). The machine- language program is in lines 200 thru 230, expressed as a string of hex- adecimal bytes with no punctuation. Thus if your machine is not an 8080/Z80 type, a program can be assembled, the listing copied into these lines, and possibly this program can be made to work with little other modification. The program asks for the most significant byte of the place where the machine-language subroutine is stored. The loader adjusts memory references by inserting the value of this byte in memory wherever necessary, after the program is loaded (lines 300 thru 330). The display area consists of 1 K bytes of memory starting on any 256-byte boundary. Lines 370 thru 400 ask for the starting location of the memory area devoted to the display, and set up base registers in the machine-language program for the left margin of each cursor's move- ment. The FILL command is like POKE. If the computer has graphics capability built-in, everything from line 60 thru 400, and the plotting subroutine (later), can be accomplish- ed in a simpler way. Disturbance tables are set up in lines 510 thru 620. The unnecessary use of symbols, instead of constants, 102 September 1979 © BYTE Publications Inc Color. VP-590 add-on Color Board allows program control of 8 brilliant colors for graphics, color games. Plus 4 selectable background colors. Includes sockets for 2 auxiliary keypads (VP-580). $69.* Sound. VP-595 Simple Sound Board provides 256 tone frequencies. Great for supplementing graphics with sound effects or music. Set tone and duration with easy instructions. $24* Music. VP-550 Super Sound Board turns your VIP into a music synthesizer. 2 sound channels. Program control of frequency, time and amplitude envelope (voice) independently in each channel. Program directly from sheet music! Sync provision for controlling multiple VIPs, multitrack recording or other synthesizers. $49* Memory. VP-570 RAM Expansion Board adds 4K bytes of memory. Jumper locates RAM in any 4K block of up to 32K of memory. On-board memory protect switch. $95.* EPROM Programmer. VP-565 EPROM Programmer Board comes complete with software to program, copy and verify 5-volt 2716 EPROMs— comparable to units costing much more than the VP-565 and VIP put together! Programming voltages generated on board. ZIF PROM socket included. $99: EPROM Interface. VP-560 EPROM Interface Board locates two 5-volt 2716 EPROMs (4K bytes total) anywhere in 32K of memory. VIP RAM can be re-allocated. $34.* ASCII Keyboard." Fully encoded, 128-character ASCII encoded alpha-numeric keyboard. 58 light touch keys including 2 user defined keys! Selectable upperand lower case. Handsomely styled. Under $50.* Tiny BASIC." VP-700 Expanded Tiny BASIC Board puts this high-level language on your VIP. BASIC stored in 4K of ROM. Ready for im- mediate use — no loading necessary. This expanded BASIC includes the standard Tiny BASIC commands plus 12 additional — including color and sound control! Requires external ASCII encoded alpha-numeric keyboard. $39.* uxiliary Keypads. Program your VIP for 2-player inter- action games! 16-key keypad VP-580 with cable ($15*) connects to sockets pro- vided on VP-590 Color Board or VP585 Keyboard Interface Card ($10*). COSMAC VIP lets you add . computer power a board at a time. With these new easy-to- buy options, the versatile RCA COSMAC VIP (CDP18S711) means even more excitement. More challenges in graphics, games and control func- tions. For everyone, from youngster to serious hobby- ist. And the basic VIP com- puter system starts at just $249* assembled and ready to operate. Simple but powerful— not just a toy. Built around an RCA COSMAC micro- processor, the VIP includes 2K of RAM. ROM monitor. Audio tone with a built-in speaker. Plus 8-bit input and 8-bit output port to inter- face relays, sensors or other peripherals. It's Circle 322 on inquiry card. easy to program and operate. Powerful CHIP-8 interpre- tive language gets you into programming the first evening. Complete docu- mentation provided. Take the first step now. Check your local com- puter store or electronics parts house. Or contact RCA VIP Marketing, New Holland Avenue, Lancaster, PA 17604. Phone (717) 291-5848. 'Suggested retail price. CDP18S71 1 does not include video monitor or cassette recorder. ••Available 1st Quarter. 1979 The fun way into computers. RCA BYTE September 1979 103 Circle 40 on inquiry card. programmable scientific programmable business desktop business programmable w/mag card desktop programmable S 49.95$ _ 99.95 S . 219.95 s. 33.95 s _ 69.95 s _ 179.95 5. 10.95 8. 8.95 S _ 25.95 S. 59.95 S . 76.95 S. 98.95 s . 399.95 s . 361.95 s. 597.00 S . T! HOME COMPUTER PRODUCTS PHC004M TI-99/4 Home Computer S1099.00 PHA2000 Dual Cassette Cable 6.95 PHP1100 Remote Controls (Pair) 29.95 PHP1500 Speech Synthesizer 149 95 COMMAND MODULES PHM3000 Diagnostic 29.95 S PHM3001 Demonstration 69.95 s PHM3002 Early Learning Fun 29.95 s PHM3003 Beginning Grammar 29.95 S PHM3004 Number Magic 19.95 S PHM30D5 Video-Graphs 19.95 S PHM3006 Home Financial Decisions 29.95 S PHM3007 Household Budget Management 44.95 S PHM3008 Video Chess 69.95 s PHM3009 Football 29.95 S PHM3010 Physical Fitness TOTAL Shipping, add 3% Cal. residents add 6% tax Amount enclosed (check or money order) 29.95 S $ $ s $ (Credit Cards for Sales ol S700 or less) Charge to my Q VISA Q MASTER CHARGE Acct # Rank * Fxp nat(> Name- Street or P.O.. \ City State. Z,P- HANDLE Figure 17: Schematic arrangement of experimental setup. Three slow and smooth distur- bances are added to a measure of the handle position (with a negative sign for the middle one), to determine the position of 3 corresponding cursors. The subject selects 1 cursor and a reference position for it, and uses the handle to maintain the cursor at that position. A run lasts about 1 minute, and 250 samples of handle position are recorded. For plotting, the cursors are reconstructed from the tables of disturbances and the corresponding records of handle position. is an attempt at acceleration. It still takes a minute to load the 3 distur- bance tables, each 250 bytes long. All long tables are strings; only 8 bits of accuracy is needed, so by using the CHR$ and ASC functions, the tables can be stored 1 byte per value instead of 5 bytes per value. Disturbances are in tables because BASIC cannot calculate them fast enough. Disturbance Dl is a sine wave and D3 is a triangular wave. D2 is a smoothed random disturbance. On reruns, only D2 is reloaded, taking about 20 seconds. The experimental run is controlled by lines 660 thru 780. Lines 660 and 680 lay down 3 arbitrary scales on the screen, while the rest repeatedly call the machine-language subroutine. For each stored value of each distur- bance, all 3 cursor positions are com- puted and plotted, and the handle position is stored in the table Hl$. The inner loop from line 710 to line 770 adjusts the duration of the ex- perimental run; here it is set up so that the disturbances change and a handle position is recorded only every fourth time the display is generated. On my system, this works out so the display is refreshed 16 times per second, and data is sampled and stored 4 times per second. The 2 OUT statements reflect my laziness; I use 2 digital-to-analog outputs to supply the voltage to the poten- tiometer that measures handle posi- tion. The data plotting routine (lines 820 thru 1010) is entered at the end of an experimental run. This routine is set up to plot either on the video screen or on a hard-copy device; it asks for the X and Y dimensions of the plot, which cursor is to be plotted, and which device is to be used. My system is set up so the typewriter is device 2 and the screen is any other device number. If you do not have this ability in your BASIC or system, delete lines 1060 and 1070 (in the subroutine that requests information about the display), and eliminate the "#2," in lines 970 and 990. In North Star BASIC, the exclamation point is short for PRINT. Only the handle position is stored as data; the cursor positions are reconstructed during plotting from the list of handle positions and the corresponding tables of disturbances. The plotting scheme is designed to work with any teletypewriter-like device. If you have legitimate graphics, you can rewrite this part and get a more pleasing result. There are 3 choices for plotting, each associated with cursors Cl, C2, and C3. Each plot shows the cursor as a C, the handle position as an H, and the disturbance acting on the cursor as a D. A dot indicates the center of the display when nothing else is there. After each plot is finished, there is a pause; hitting the carriage return will cause the program to ask about the next plot. If the question about the Y dimension of the display is responded to with a 0, the program will reload the random disturbance table and issue a prompt for another ex- perimental run. The old data will be destroyed. Remember, it takes about 20 seconds to reload the random disturbance table. Do not panic if 104 September 1979 © BYTE Publications Inc looking for a more meaningful relationship with your computer? Learn to speak its language with easy-to-use Heathkit Computer Language Programs. Heathkit Self -Instruction Program for ASSEMBLY Language Programming. « Use the full capacity of your computer. 9 Execute programs faster. Store more in less space. ASSEMBLY Language lets you do everything your computer is capable of doing. It's the most versatile, most powerful language you can use. ASSEMBLY includes a mnemonic for every machine oper- ation. No time is wasted interpreting, so programs run much faster. ASSEMBLY makes more efficient use of memory. It stores in less space because codes are shorter, more explicit. The Heathkit Self-Instruction Program teaches you to pro- gram your computer in ASSEMBLY Language. You learn at your own pace through a special text designed for self- study. An exercise workbook provides hands-on experience with programming exercises performed by you on your com- puter. You learn in a way that's fast, fun and thorough. The Heathkit Program is designed for computers using the popular 8080/8085/Z80 microprocessor series. This includes the Heathkit H8, H88 and H89 Computers. The concepts of the program, however, can be applied to any computer. Now's the time to learn the language that puts you in total command of your computer's full potential. Send today for the Heathkit Self-Instruction Program for ASSEMBLY Language. Order No. EC-1108: $49.95, plus shipping and handling. Heathkit Self -Instruction Program for BASIC Language Programming. 9 Easiest of all languages to use. • Now easiest of all to learn. More programs are written in BASIC than any other lan- guage. Because it uses English statements and commands, it's the easiest to learn and the easiest to use. When you know BASIC you can adapt and run hundreds of existing programs. You can exchange programs with others. And you can write your own programs for your specific needs. In 14 easy-to-follow segments, the Heathkit Program covers all formats, commands, statements and procedures. A special workbook provides programming instructions and experiments performed on your computer. You learn practi- cal problem-solving techniques. Until you know BASIC, you're missing the full selection of programs available to you. Send today for the Heathkit Self- Instruction Program for BASIC Language. Order No. EC-1100: $39.95, plus shipping and handling. Send Today or Phone for faster service on VISA and Master Charge. 616-982-3411 Heath Company, Dept. 334-570, Benton Harbor, Ml 49022 Heath Company SHIP MY ORDER TO: Name. Schlumberger Dept. 334-570 Benton Harbor, Ml 49022 (please print) Address. City PLEASE RUSH ME: □ ASSEMBLY Language EC-1108 $49.95, plus $2.60 shipping & handling. □ BASIC Language EC-1100 $39.95, plus $2.40 shipping & handling. _State_ Zip- Total price Michigan residents add 4% sales tax MONEY-BACK GUARANTEE OF SATISFACTION If you are not completely satisfied with the EC-1100 BASIC Program or the EC-1108 ASSEMBLY Program, simply return programs for a full refund of purchase price. Add shipping & handling Total enclosed □ check □ money order □ Heath Revolving Charge Or charge my □ VISA/BankAmericard □ Master Charge Account No. Expiration Date Signature X . (NECESSARY TO SEND MERCHANDISE) Prices are mail order and subject to change without notice t.U-Vtb BYTE September 1979 105 there is a long pause. At line 1260 there is a utility routine that converts any hex- adecimal number up to 10 digits to a decimal number. I used it while writing the program. It calls the con- version subroutine starting at line 1130. Running the Experiments If you possibly can, take the trouble to set this experiment up. Nothing can take the place of actually experiencing yourself as a control system and understanding things that you have taken for granted all your life. Here is a typical run for the benefit of the many readers who do not have the equipment to do this; the data will then be observed. Here is an old friend, Chip Chad (from part 1 of this series), glaring at the screen and maintaining a choke-hold on the handle, waiting for the experimenter to hit the return key at line 610. The experimenter reaches in and taps the key. The reference scales slide up into place and the 3 cursors pop into view, moving. Chip picks the middle one as most people do the first time, decides to keep it on the middle + mark, and after a few wobbles succeeds. 'So what?" he says. If learning were being studied, good information could be obtained from this first run. But the plan is to see Chip acting as a competent con- trol system, so his first effort is praised and he is given another run (answering the query about Y dimen- sion with a 0). After the second run, the data is plotted for each cursor. Figure 18 shows the data for each cursor, number 1 on the left, 2 in the middle, and 3 on the right. The 2 end plots are a mess, but the middle plot shows a striking symmetry. The Cs march more or less down the center of the screen, deviating a little to left and right, but maintaining a constant position on the average. The Ds make a random-looking pattern, and the Hs follow almost the mirror image of the D pattern. Looking carefully at the middle plot, could it be said that the handle position or motion looks like any sort of regular function of the cursor posi- tion or motion? There may be some relationship, but it certainly is not clear. Probably, nobody would claim that the large, smooth motions of the handle could be reconstructed ac- curately on the basis of measurements of cursor position (that is, recon- structed roughly or statistically with accuracy, especially if handle ac- celeration is compared with cursor deviation from the average position). The best which could be hoped for would be some statistical relationship (eg: a small signal buried in much noise). On the other hand, the relationship between the handle position and the magnitude of the invisible distur- bance is obvious and quantitative. It is seen that the handle position is the mirror image of the disturbance magnitude with an error of only a few percent of full scale. There is much signal and little noise in that relation- ship. Here is the situation. There is 1 measure of Chip's behavior, H. There are 2 variables, D and C, either of which might have some relationship to that behavior. Which variable, D or C, would be selected by any statistical test as the most probable cause of the behavior? Of course, D would be selected. In fact, a formal statistical analysis, like those done in every scientific study of behavior, shows D to be the only significant contributor to the behavior, while C, the cursor position, is rejected as an irrelevant variable! That is a paradox, however, from Figure 18: A typical run for a practiced subject. In figure 18a is the record for Dl, Cl, and H. Figure 18b has the record for D2, C2, and H; figure 18c has the record for D3, C3, and H. In figure 18b, the cursor is held near the center, while the handle position is at all times very nearly the mirror image of the disturbance amplitude. It is very easy to decide which cursor was under control. D C H H C H C H C H D c H D c H D C H DC DC H DC H D C H D C H D C D H C H C H C H C D C D C DC DC D C D C C 106 September 1979 © BYTE Publications Inc Figure 19: Cause and effect paradox. Under the old concept that stimuli cause behavior, the cause and effect chain runs from the disturbance to the cursor, through the subject, to the behavior. However, the correlation of the disturbance and the cursor position is very low, as is the correlation of the cursor position and handle position (for the con- trolled cursor). This would lead to a prediction of an even lower correlation of distur- bance and behavior. In fact, that correlation is normally very high (0.99 or better). Only the control theory analysis of this experiment can explain this otherwise paradox- ical situation. CORRELATION > 0.99 — c- SUBJECT CORRELATION < 0. CORRELATION < 0.1 the traditional point of view. The only way D can affect Chip's behavior is through its effects on C, since all that Chip can sense is the cursor position. The disturbance itself is invisible. If C does not correlate with the behavior, then how can anything that acts exclusively through effects on C correlate any better with behavior? Yet a typical correlation between C and H is around 0.1, while the correlation of H with the corresponding D is typically 0.995. See figure 19. That is the proof mentioned earlier. The old cause-effect model fails utterly when applied to this situation. The question then is, why have generations of intelligent people believed that behavior is caused by sensory stimulation? The answer is clear: they have been fooled by a monstrous illusion. The illusion would be easier to see if there was some visible, direct in- dication of the magnitude of the disturbance. Suppose there were a moving D (or a number that con- tinually reflected the magnitude of D) on the display. Clearly, if Chip managed to control C without that indication, he could still do so; he could ignore it and perform as well as ever. However, something has now been added that would mislead a bystander who did not understand control theory. That bystander could now see 2 variables, both able to affect Chip's senses. Taking the apparent relation- ships at face value, it would be clear that the indication of D was accur- (18b) „H C . C. i C. D H .C D H C. D H C. D H C. D H .C D H C. D H C. D i C D C c c. c. C D H CD H CD D C. H D C H D C H D C. H D C. H D CH CH C. H D C . H D C H D C H D C. H ) C K C. c. c c ) C. H D C H D C H H C D H C D H .C D H C. D H C. D H C D H C. D HCD D C. H D C H D C H DC (18c) CD H D C. D C D C D C D C, D D D D D D H H H C H C H C H C H C H C HC HC i DC D D C D C D C D C D C DC I CD H CD H CD H H H C H C H C H C H C H CH D HC D H C D H C D H C D H C H D C H DC C D C D C D C D C D C D C C D C D C D C D C D D D D D D D D H C H H H H H H September 1979 © BYTE Publications Inc 107 Our MacroFloppy™ goes twice the distance. For $ 695. Introducing the Micropenis MacroFloppv™:1041 and :1042 disk drive sub- systems. For the S-100/8080/Z-80 bus. Packing 100% more capacity into a 5%-inch floppy disk than anyone else. 143K bytes, to be exact. For as little as $695. The MacroFloppy:1041 comes with the Micropolis Mod I floppy packaged inside a protective enclosure (without power supply). And includes an S-100 controller. Interconnect cable. Micropolis BASIC User's Manual. A diskette con- taining Micropolis BASIC, and a compatible DOS with assembler and editor. The :1041 is even designed to be used either on your desk top, or to be inte- grated right into your S-100 chassis. The MacroFloppy:1042 comes with everything the :1041 has, and more. Such as d.c. regulators, its own line voltage power supply, and, to top it off, a striking cover. Making it look right at home just about anywhere. Both MacroFloppy systems are fully assembled, tested, burned-in, and tested again. For zero start-up pain, and long term reliability. They're also backed up by our famous Micropolis factory warranty. And both systems are priced just right. $695 for the MacroFloppy:1041 and $795 for the MacroFloppy:1042. You really couldn't ask for anything more. At Micropolis, we have more bytes in store for you. For a descriptive brochure, in the U.S. call or write Micropolis Corporation, 7959 Deering Avenue, Canoga Park, California 91304. Phone (213)703-1121. Or better yet, see your local dealer. MICROPOLIS More bytes in store for you. ately associated with the handle posi- tion; while the movements of the cur- sor, such as they are, show no such association. Furthermore, the varia- tions of D are large and smooth, and there is no observable relationship between D and C. Why should the bystander suspect that C is being affected by D in one way and affected by H in an opposite way? The ob- vious conclusion is that the variations in D are causing Chip's behavior, while C has nothing to do with his behavior, especially if C does not vary more than the fixed background scales do. If the screen were full of irrelevant cursors, jiggling around slightly, how could the bystander pick C as something of special impor- tance? If BASIC were fast enough, I would have included such irrelevant cursors; the point being made here would then be obvious. An organism is surrounded by a world full of variables; variables that change within widely diverse ranges. The organism receives many signals from its internal parts, too. In that sort of situation, if the organism is controlling some of the variables, it will react strongly and smoothly to any disturbance tending to alter 1 of the controlled variables. The result is that it will seem to be responding directly to the disturbances. There will be no obvious indication that it is controlling anything at all. There is every excuse for even the best of scientists to have observed the rela- tionship between disturbance and behavior, and to have missed the very existence of controlled variables. The name for such disturbances is stimuli. Once in a while, an ex- perimenter must have accidentally picked a real controlled variable to call a stimulus, but the chances are against that. If an attempt is made to manipulate a real controlled variable, the organism will have to be strapped down to keep it from interfering. That is what is done in such cases. If the organism insists on acting like a control system, forcibly break the loop and make the organism conform to the theory. As a famous psychologist said, the theme is "Behave, damn it!" It never occurs to such stong-willed individuals that they might have the wrong idea about what is happening. There is more in this elementary ex- periment than meets the eye. If all psychologists were to experience it, and try to meet the challenge of ex- plaining these effects using any stan- dard theory, the result would be a total collapse of that science, follow- ed by a rebirth. However, many jobs would be threatened. What has happened instead is that a handful of psychologists has supported this theory, another handful has taken up arms against it, and most have resolutely ignored it. I suggest that you run this experi- ment many times with subjects con- trolling all 3 cursors. Every case will show that mirror-image relationship between D and H and little relation- ship between C and either D or H. If the previous parts of this series are studied and all the relationships that make up a control system thought about carefully, it will be evident that there is no other explanation for what is going on here. If you get nothing else out of this, you should acquire an intuitive feel for a new theory of how behavior works. You might even begin to understand how to design a robot in a new way. It is time now to try to fulfill a pro- 108 September 1979 © BYTE Publical ions Inc TM MetaFloppy The Micropolis MetaFloppy™ gives you more than four times the capacity of anyone else's 5%-inch floppy Because it uses 77 tracks instead of the usual 35. The field-proven MetaFloppy. with thousands of units delivered, comes in a complete family of models. And, like our MacroFloppy™ family of disk drives, MetaFloppy is designed for the S-100/8080/Z-80 bus. For maximum capacity, choose our new MetaFloppy: 1054 system. Which actually provides you with more than a million bytes of reliable on-line stor- age. For less money than you'd believe possible. The MetaFloppy:1054 comes complete with four drives in dual config- uration. A controller Power supply. Chassis. Enclosure. All cabling. A new BASIC software package. And a DOS with assembler and editor. There's even a built- in Autoload ROM to eliminate tiresome button pushing. If that's more storage than you need right now, try our MetaFloppv:1053, with 630,000 bytes on-line. Or our Meta- Floppy: 1043, with 315,000 bytes on-line. Either way, you can expand to over a million bytes on-line in easy stages, when you need to. Or want to. In other words, if your application keeps growing, we've got you covered. With MetaFloppy. The system that goes beyond the floppy. For a descriptive brochure, in the U.S. call or write Micropolis Corporation, 7959 Deering Avenue, Canoga Park, California 91304 Phone (213) 703-1121. Or better yet, see your local dealer MICROPOLIS™ More bytes in store for you. goes beyond. mise implied in part 1, to show how anyone with a home computing system can make important contribu- tions to this new science of human nature. The best way this can be done is to start with the experiment used, and to show how it can be extended to become a powerful tool for in- vestigating human organization. The main objective will be to introduce the test for the controlled variable, the nearest approach I know of to mind reading. More Controlled Variables Once subjects controlling all 3 cur- sors have been seen, it might seem that the possibilities of this experi- ment have been exhausted; this is not the case at all. There are controllable variables all over that screen; all of them can be controlled by the same means, movements of the handle in 1 dimension. Discovering them is a good way to get out of the habit of thinking that we simply perceive our environment, and start a new way of thinking: to recognize that we con- struct perceptions, imposing order on our experiences far more than recognizing order. As you will see, a controlled variable does not have to be "real" at all. Here is an example. It is possible to perceive the relative position of any of the 2 cursors. The handle affects C2 in a direction opposite to its effects on Cl and C3, so the relative position of Cl and C3 cannot be con- trolled because the handle does not affect it. However, it is possible to keep Cl even with C2, or C2 even with C3; in fact, it is easy. A plot of the results would involve plotting C2-C1 or C3-C2 instead of just C, and D2-D1 or D3-D2 instead of just 1 disturbance. The mirror image rela- tionship with H would be as good as ever. Do not forget that C2-C1 and C3-C2 are variables. Any value of the variables can be selected as a reference level (eg: Cl to be 1 inch to the left of C2). These are examples of higher-level controlled variables. If the subject could not perceive the present posi- tions of the cursors, he or she cer- tainly could not perceive their relative positions. Relative position is derived from perceptions of in- dividual positions, but not vice versa. In order to control relative positions, it is necessary to control (or at least vary) individual positions, but in- dividual positions can be controlled without controlling relative posi- tions. These are the relationships one looks for to map out a hierarchy of perception and control. Other relative perceptions can be controlled. All 3 cursors can be kept lying in a straight line, at least within the range where 1 of them does not fall off the edge of the display and pop up at the other edge. Reducing the amplitude of the disturbances would eliminate that problem. Also, the 3 cursors can be made to form any fixed angle, subject to the same limitation. There may be more static patterns that can be controlled, but I have not thought of any. This is, after all, a simple display. It is not, however, limited to static conditions. Suppose the subject visualizes a pattern in which 1 cursor moves back and forth slowly between 2 limits. This pattern can easily be maintained, the handle moving just enough to produce it, and enough more to cancel the effects of any of the disturbances. A similar oscillation could be maintained for the relative September 1979 © BYTE Publications Inc 109 variables. This is a still higher-level variable, a temporal pattern. The subject chooses which temporal pattern to perceive, and what state of that kind of pattern to maintain. Control still requires only the use of the 1-dimensional effect caused by the handle. There is clearly an infinite range of different temporal patterns, ranging from a simple steady motion in 1 direction to completely arbitrary mo- tions and rhythms. There is an unlimited number of potential con- trolled variables in this simple display. Anything that can be perceived, and that the handle can affect in a systematic way, can be controlled. For all of these examples of con- trollable perceptions, it is essential to remember that the disturbances are acting all the time. This is not a matter of producing any particular behavior. The cursor cannot be made to move slowly back and forth be- tween fixed limits just by moving the handle slowly back and forth be- tween fixed limits. The handle might be moving the wrong way at many moments, when the disturbance tends to make the cursor move faster than the reference pattern being con- sidered. There is no one-to-one cor- respondence between handle position or velocity and cursor position and velocity, because of those ever- present disturbances. Regularities of behavior are not being looked at here, but regularities of controlled perceptions. If there were a slowly oscillating prism between the display and the subject's eyes, a regular pat- tern of movement of the cursor on the screen would not be seen. The subject controls the visual image, not the reality. For the higher-level variables, the subject controls some function of the visual image (often the controlled variable could not be found, even on the retinas). One could create displays of far greater complexity, and provide means of affecting the display that have more than 1 degree of freedom to explore a staggering range of possi- ble controlled variables. This is what I suggest be done. The first step in the development of any new science is ac- quire the facts; here the most needed Introducing... MINI-FLEX Designed Specifically to Protect 5" Diskettes fflA The Newest Member of The Advance Access Diskette Protection Family For Further Information CALL TOLL FREE 800 323-0254 ADVANCE ACCESS GROUP 1 0526 W. Cermak Westchester, I L 601 53 31 2 562-521 "Manufacturers of Information Processing Supplies" facts concern what variables human beings can actually control. What is needed is a large and simpleminded program of recording the obvious and obscure. What is needed is a body of definitions of variables in every sensory mode that people have been able to control. Order and system count much less than sheer volume of data at this point. In fact, an unsystematic gathering of data may be the best kind, since it will not be constrained by theories about what people ought to be able to con- trol. Anything which can be a way of testing is worth testing at this stage. The possibilities are limited only by the imagination. We do need some sort of ordering principle — some criterion for judging the reality of any proposed controlled variable. This is where the test ap- pears; here is how it works. Test for Controlled Variables The first thing to remember when investigating a possible controlled variable is that in order for something to be controllable it has to be variable. There is neither the means nor the need to control the existence of the Empire State Building or the planet Jupiter. Not all perceptions are controlled. Some are just distur- bances; some are just there. One might think initially about controlling, for instance, a car. People often speak casually about controlling things. But what is meant is controlling something about those things. A person cannot really con- trol a car; but under proper cir- cumstances its shape, its color, its price, its speed, its direction, its park- ing place, its dirtiness, its dangerousness, its desirability, its altitude, or the flatness of its tires can be controlled. A car, after close in- spection, proves to be composed en- tirely of hundreds or even thousands of variables. Together they create "car-ness" in our perceptions. In- dividually, or in groups, most of them can be affected by one means or another, and can be controlled if it is worth the effort. You can even make the car disappear instantly by closing your eyes. Keep remembering that what is controlled is really a percep- tion. The first step in applying the test for the controlled variable is to define a variable. You do not have to know in advance if it is a controlled 110 Seplember 1979 © BYTE Publications Inc Circle 5 on inquiry card. For your SWTP 6800 Computer . . PERCOM's FLOPPY DISK SYSTEM Ready to plug in and run the moment you receive it. Nothing else to buy, no extra memory. No "booting" with PerCom MINIDOS-PLUSX™, the remarkable disk operating system on EPROM. Expandable to either two or three drives. Outstanding operating, utility and application programs. PERCOM DATA COMPANY, INC. 21 1 N. Kirby Garland, TX 75042 (214)272-3421 For the low $599.95 price, you not only get the disk drive, drive power supply, SS-50 bus controller/interface card, and MINIDOS-PLUSX™, you also receive: • an attractive metal enclosure • a fully assembled and tested inter- connecting cable • a 70-page instruction manual that includes operat- ing instructions, schematics, service procedures and a complete list- ing of MINIDOS™ • technical memo updates — helpful hints which supplement the manual instructions • a 90-day limited warranty. SOFTWARE FOR THE LFD-400 SYSTEM Disk operating and file management systems INDEX™ The most advanced disk operating and file management system available for the 6800. INterrupt Driven Executive operating system features file-and-device-independent, queue-buffered character stream I/O. Linked-file disk architecture, with automatic file creation and allocation for ASCII and binary files, supports sequential and semi-random access disk files. Multi-level file name directory includes name, extension, version, protection and date. Requires 8K RAM at $A000. Diskette includes numerous utilities $99.95 BASIC Interpreters and Compilers SUPER BASIC A 10K extended disk BASIC interpreter for the 6800. Faster than SWTP BASIC. Handles data files. Programs may be prepared using a text editor described below $49.95 BASIC BANDAID™ Turn SWTP 8K BASIC into a random access data file disk BASIC. Includes many speed improvements, and program disk CHAINing $1 7.95 STRUBAL+™A STRUctured BAsic Language compiler for the pro- fessional programmer. 14-digit floating point, strings, scientific func- tions, 2-dimensional arrays. Requires 20K RAM and Linkage Editor (see below). Use of the following text editors to prepare programs. Complete with RUN-TIME and FLOATING POINT packages $249.95 Text Editors and Processors EDIT68 Hemenway Associates' powerful disk-based text editor. May be used to create programs and data files. Supports MACROS which perform complex, repetitive editing functions. Permits text files larger than available RAM to be created and edited $39.95 TOUCHUP™ Modifies TSC's Text Editor and Text Processor for Per- Com disk operation. ROLL function permits text files larger than available RAM to be created and edited. Supplied on diskette com- plete with source listing $1 7.95 Assemblers PerCom 6800 SYMBOLIC ASSEMBLER Specify assembly options at time of assembly with this symbolic assembler. Source listing on diskette $29.95 MACRO-RELOCATING ASSEMBLER Hemenway Associates' assembler for the programming professional. Generates relocatable linking object code. Supports MACROS. Permits conditional assembly $79.95 LINKAGE EDITOR - for STRUBAL+™ and the MACRO-Relocating assembler $49.95 CROSS REFERENCE Utility program that produces a cross- reference listing of an input source listing file $29.95 Business Applications GENERAL LEDGER SYSTEM Accommodates up to 250 accounts. Financial information immediately available — no sorting required. Audit trail information permits tracking from GL record data back to source document. User defines account numbers $199.95 FULL FUNCTION MAILING LIST 700 addresses per diskette. Power- ful search, sort, create and update capability $99.95 PERCOM FINDER™ General purpose information retrieval system and data base manager $99.95 tu trademark of PERCOM Data Company, Inc tm trademark of Hemenway Associates Company Now! The LFD-800 and LFD-1000. Add one, two or three LFD-800 drives and store 200K bytes per drive on-line. Add one or two (dual-drive) LFD-1000 units and store 800K bytes per unit on-line. Complete with interface/controller, DOS, cable & manuals. Two-drive systems: LFD-800 — $1549; LFD-1000 — $2495. PERCOM 'peripherals for personal computing' BYTE September 1979 111 Circle 305 on inquiry card. variable; you do not even have to know where the supposed control system is. All you have to do is to pick out something that you know is variable and "push" on it. By push I mean to apply a distur- bance that under normal cir- cumstances should have a predictable direction and amount of effect on the variable. If I push hard enough on a life-sized statue, it should tilt in the direction of the push. Perhaps it will topple in that direction according to the simple laws of mechanics. Having selected a variable and ap- plied a push to it, the next step is to measure the actual effect of the push. I predict that pushing on this statue should make it tilt a certain amount in a certain direction. I apply the push and observe the tilt. If the actual effect is far smaller than the predicted effect, common sense indicates that something must be pushing back. If the pushing-back is always just enough to cancel any amount or direction of disturbance (within some limits), it can be con- cluded that the pushing-back is systematic. The mirror-image effect that has been observed is what is wanted. It is necessary to discover what is pushing back, and how it is doing the pushing. Perhaps, examining the statue carefully, an iron rod is found supporting its back from its base. In that case, a conclusion is made that there were not enough facts to make a correct prediction of the effects of the push; the bending moment of the rod should have been taken into account. But if no simple explanation for the failure of the prediction is found, one must look further. Suppose it is discovered that the base of the statue seems to move when pushed. If there is a push to the east, the base tilts to the west moving the center of support east of the center of gravity of the statue, and thus creating a counterforce. Suppose this tilt of the base is found to be always just what is required to offset the effects of the push. It can be con- cluded that one may be on the trail of a control system. What has been done is to find out something about the means of con- trol, the path by which the output of the control system, if it exists, might be linked to the controlled variable (the angle between the statue's longitudinal centerline and the ver- tical). Finding this link is a necessary step in the test. That step will usually lead to discovering the physical control system. Tracing the wires that work the motors that tilt the base of the statue, you find a black box a few yards away from the statue. That may be the control system, or at least all of it that is not its actuators (which have been found). There is still one step to be taken. You cannot be completely sure of the nature of the control system until you discover the variable it is really sensing. The situation has been approached with human prejudices; to me, it seems that the controlled variable is the orientation of the statue, a geometric or visual variable. Perhaps that variable is only related to the real controlled variable. What must be found now are the sensors that the control system is using. Thinking in visual terms, you might look for a photocell that detects the tilt. Suppose a photocell is found on a stand near the statue. The test calls for breaking this link, preventing the sensing of the statue. The result should be that the effect of the push returns to what would be predicted from mechanical laws. So the photocell is covered and the disturbances are applied again. What happens is that the floodlights il- luminating the statue turn on. The statue still resists the push — the photocell was for something else. By careful searching 4 strain gauges built into the base of the statue are discovered. These provide a signal showing where the center of thrust is, and the wires from the strain gauges run over to that black box. Discon- necting the wires shows that now the push succeeds in tilting the statue. As soon as its tilt becomes marked, an angry groundskeeper comes leaping out of the bushes and arrests the ex- perimenter. Aha! You may have discovered another control system controlling the state of the statue. To recapitulate, the test for the controlled variable involves the following steps: 1. Define a variable. 2. Apply various amounts and directions of disturbances directly to the variable. 3. Predict the expected effects of the disturbances, assuming no control system is acting. 4. Measure the actual effect of the disturbances. 5. If the actual effect is essentially the same as the predicted effect, stop. No control system is found. 6. If the actual effect is markedly smaller than the predicted effect, look for the cause of the opposition to the disturbance, and determine that it results from systematic variations in some other variable. If such a cause is found, it may be associated with the output of a control system. 7. Look for a means of sensing the controlled variable. If none is found, stop: no control system is proven to exist. 8. If a means of sensing is found, block it, so the variable cannot be sensed. If control is not lost, the sensor is not the right one. If no such sensor is found, stop: no control system is proven to exist. 9. If all steps of the test are passed, the variable is a controlled variable, its state is its reference level, and the control system has been identified. To apply step 8 of the test to our computer experiment, cover the cur- sor suspected of being controlled with a cardboard strip. Control should be lost. Cover each cursor. The covered one will never pass the test. The other steps are easily carried out. Concluding Remarks Now it is up to you. You can test controlled variables involving inten- sity, sensation, configuration, change, sequence, relationship, strategy, principle, and system con- cepts having to do with visual, auditory, tactile, kinesthetic, and other senses. Good luck with the programs, and good hunting for controlled variables. I will be interested to receive word about what people are doing with the information covered in these articles. ■ BIBLIOGRAPHY Powers, W T, Behavior: The Control ot Perception, Aldine Publishing Co, 200 Saw Mill River Rd, Hawthorne NY 10532, 1973. 112 September 1979 © BYTE Publications Inc "HOOKS OF INTEREST TO COMPUTER PEOPLE" 70 Main street Peterborough, New Hampshire 03458 Circle 36 on inquiry card. BYTE September 1979 113 I ( I Tummg computer programmers into computer composers! ■//7i«;iilMtt\i^ The BYTE Book of For the first time: Hard-to-obtain computer music material has been collected into one convenient, easy-to- read book. The BYTE Book of Computer Music com- bines the best from past issues of BYTE magazine with exciting new material of vital interest to computer experimenters. The articles range from flights of fancy about the reproductive systems of pianos to Fast Fourier transform programs written in BASIC and 6800 machine language Included in this fascinating book, edited by Christopher P. Morgan, are articles discussing four-part melodies, a practical music interface tutorial, electronic organ chips, and a remarkable program that creates random music based on land terrain maps! ISBN 0-931718-11-2 $1000 Buy this book at your favorite computer book store or order direct from BYTE BOOKS Add 6CXC per book for postage and handling EMI BMNS "BOOKS OF INTEREST TO COMPUTER PEOPLE" 70 Main Street Peterborough, New Hampshire 03458 114 BYTE September 1979 Circle 36 on inquiry card. iiiiiiiiiniii iiiiini iiiiiiiiiiiiiiiiiiiini milium mimim iiiiiiiiinii miiiiiiiii i iimimimimii iiinini iiiiim iiiiimi BYTE News .... lIlllllllllllilllllllllllllllilllllllltltlllllllllllllllllllllllllllltlllllllllllllllllllllllllElllllllllillllllllllllllllllllllllllllllllilllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllll S-100 8086 AND Z8000 CARDS COMING: At least 6 S-100 product manufacturers are about to release 16-bit processor cards for the S-100 bus that use the Intel 8086 and Zilog Z8000. One such card has already been announced, a 8086 processor card from Seattle Computer Products Inc, Seattle WA. All will conform to the Institute of Electrical and Electronic Engineers (IEEE) S-100 standard that is soon to be adopted. They will work with most 8-bit memory cards using byte-serial read/write. However, for full speed operation you will need either a true 16-bit memory card or a modification of your present memory cards. To modify memory cards requires cutting traces, some rewiring, and adding some logic circuitry. Microsoft has already announced and demonstrated an 8086 BASIC, and is working on a Z8000 BASIC, as well as other 16-bit software. Digital Research is working on a 8086 version of CP/M. Most 16-bit software in development will be designed for multiprocessing environments, using real-time clocks and interrupt-driven user-inputs. CP/M 2.0 TO BE RELEASED SOON: There is no doubt that the most widely used disk operating system for microcomputer is CP/M, developed by Gary Kildall of Digital Research, back in 1974. Although originally written for the Intel 8080 development system, it was adapted to run on 8080, 8085 and Z80 systems of many types. Its power and flexibility puts microcomputers in the big leagues by providing features and capabilities normally found on the bigger models. Gary Kildall is planning to release the 1st major revision to CP/M (Version 2.0). It will use a real- time clock and be interrupt-driven. It will support all present CP/M software. Look for its release around September 1st. RANDOM RUMORS: Matsushita Inc is rumored to be working on a $250 printer which will generate "letter quality" type. It will print at 15 characters per second and include a keyboard. Rumors about Hewlett-Packard's Personal Computer are getting warmer. It may be introduced in time for the Christmas market. Expected to sell in the $2500 area, it will have a 5-inch black and white monitor, 16 K bytes of programmable memory, BASIC in read-only memory, a built-in thermal printer and cassette I/O (input/output). Texas Instruments is developing a 3 or 4-inch Winchester- type disk drive to sell for approximately $50. Shugart is about to start delivery on the $70 5-inch floppy disk drive made by Matsushita. Infoton, a video terminal manufacturer, is rumored to be about to introduce a video terminal which will sell for less than $400 in large quantities. It will use the Zilog Z8 micro- processor and have a total of only 16 integrated circuits. All circuitry will be on 1 printed circuit card, the power supply will be transformerless, and a special elastomeric keyboard will be used. HAND-HELD COMPUTER IN DEVELOPMENT: Matsushita Electrical of Japan and Friends-Amis Inc of CA have agreed to develop and produce "the first practical hand-held personal computer." The size of a hand-held language translator, the unit could be in production by the end of the year. The computer will be able to accept preprogrammed and user programmed memory capsules. Prepro- grammed capsules will include information on business, science, language, education, etc. The computer will have modular construction, enabling new technology modules to be added as they are introduced. Add-ons will include a miniprinter, miniature video display, and a voice synthesizer. MICRO-MOUSE CONTEST FINALLY ENDS: The 2 year long "Amazing Micro-Mouse Contest" run by the IEEE has finally ended. Although several thousand entries were received, less than 100 actually ran the maze. The contest's objective was to design a robot-type device which could negotiate and learn a maze as it went through. The trials were held at conventions of the IEEE, NCC shows and PC-78. The ultimate winner was entered by the team of Howard P Katseff and Roy Tramwell from Bell Labs, Holmdel NJ. Their mouse ran the 8'/2 by 8'/2-foot maze in just under 30 seconds. It employed a Z80 microprocessor with 4 K bytes of read-only memory and 1 K bytes of programmable memory. Second prize was taken by the team from Batelle Memorial Institute of Richland WA. Art Boland, Ron Dilbeck and Phil Stover's mouse ran the maze in just over 31 seconds. One high performer was actually nonprocessor controlled, and ran the maze in just under 40 seconds. September 1979 © BYTE Publications Inc 115 VOICE-OPERATED TV DEMONSTRATED: Sanyo Electric Co recently demonstrated a television receiver that responds to voice commands to turn on and off and switch stations. Utilizing a micro- processor, the unit compares the voice input to voice patterns stored in memory. The unit has a 30- word vocabulary, and can respond to the voices from 2 different people. Furthermore, the voice input can be used to play games. Sanyo has not announced any immediate plans for incorporating the receiver into its television sets. APL FOR MICROCOMPUTERS: Despite a report in an earlier BYTE NEWS column, Quark has decided against introducing its APL microcomputer using the Intel 8086 microprocessor. JAPANESE MOVING SWIFTLY INTO MICROCOMPUTERS: At least 9 Japanese manufacturers are presently manufacturing microprocessor integrated circuits. Approximately 80 different micro- processors are being made. Most of them are original designs including advanced features (eg: analog-to-digital converters, multiply /divide, counter/timers, etc). Five different 16-bit micro- processors are already in production. Furthermore, over a dozen personal computers/trainers are in production to support a very strong interest in personal computers in Japan. Thus far only a few units are available for export. MOTOROLA ANNOUNCES 68000 DELIVERY AND PRICES: Motorola has announced that it expects to start shipping limited sample quantities of its new 68000 16-bit microprocessor by the end of the year. Single unit price will be $249. Limited production quantities are expected to be available by the end of the 1st quarter of 1980, with full production by late 1980. No second source arrangements have been finalized. 75 MEGABYTE WINCHESTER DRIVE RUMORED: At least 6 companies exhibited 8-inch Winchester-type drives at the recent NCC show. All of the drives could fit into the same space as an 8-inch floppy disk drive, and provided from 10 to 45 M bytes of storage. At least 8 companies will be delivering these drives by the end of the year, and a 75 M byte version is expected next year. The drive should sell for under $2000 in quantity. PERSONAL COMPUTER MANUFACTURERS RANK WITH COMMERCIAL DATA PROCESSORS: Datamation magazine, in their most recent annual report of the top 50 US companies in the data processor industry, disclosed some interesting facts about changes in the computer industry. For the 1st time a personal computer manufacturer, Tandy, ranked among the top 50 in computer equipment sales, and Commodore ranked second among fastest growing companies. Commodore had a 190% increase in sales in 1 year, to $75M. Tandy(ranked 43rd)reported computer sales of $105M and total company sales of $1,152M resulting in a net income of $76M. The company reported a sales gain of only 11.6% (which is about equal to the rate of inflation, and hence could be considered sales growth). If Commodore continues to grow at its past year's pace, it too will soon rank among the top 50. It was reported that 63% of Tandy's computer revenues were from TRS-80 sales, 26% from peripherals, 10% from services and 1% from supplies. Each data processing company in the top 50 reported sales increases, and most were 20% or better. For example, IBM's sales rose almost 28%, while Digital Equipment Corporation's sales rose nearly 36%. In fact, none of the traditional maxi or mini makers appear to have been affected by personal computers, despite the predictions that were made 2 and 3 years ago. MAIL: I receive a large number of letters each month, as a result of this column. If you write to me and wish a response, please include a stamped self-addressed envelope. Sol Libes ACGNI 1776 Raritan Rd Scotch Plains NJ 07076 116 September 1979 © BYTE Publications Inc o Consu Wants fre ents the ^ ^o a to ong ^e , WgSSwiW en «jg sv y stem. efficient, an ^^^J^J^r^l" . T^e most a ° d aV 8jVa»g- tfaC \n9- ^ e o o o o o o '.i »*»""*? He SuW " memo" oo"*So aoo "»■* To?e«oo b < 3 i < . A, b4 • b5 b6 • br • be • a K r> K fl K o he 'K fc\ fc\ fc\ C^\ ^ < > i i 1 r < > T T ii T i> T ii m m r) 7 STROBE n 7 n 7 m m rh Figure 1: Phototransistors in the paper-tape reader. Note the placement of cell between bits 3 and 4. The active element is reversed in orientation. DATA PULSE STROBE PULSE STROBE PULSE AFTER CONDITIONING Figure 2: The strobe pulse is centered in the active signal from the data holes. UP: DOWN: READ: IN port# RAL JNCUP IN port # RAL JC DOWN IN port# RETURN READ INPUT PORT SHIFT 1 BIT LEFT JUMP TO UP IF CARRY BIT NOT SET READ INPUT PORT AGAIN SHIFT 1 BIT LEFT JUMP TO DOWN IF CARRY BIT SET READ INPUT PORT DATA BYTE WITH 7 BITS OF DATA IN REG A Listing 1: Simple 8080 assembly language program for inputting the data from the paper-tape reader. bits of data available to the input pins DI-0 thru DI-7 are latched through to the output pins DO-0 thru DO-7 by each positive pulse at the STROBE pin. Since most paper-tape programs used with today's microprocessors use only 7 bits of the 8-bit ASCII code (bit 8 being vertical parity), it is con- venient to use this 8th bit as the strobe sense line. When connecting the output pins of the latch to the pro- cessor input port, simply sele ct strobe signal STROBE or STROBE and con- nect it to the pin corresponding to bit 8. The software required to read in such data is shown in listing 1, where bit 8 is the STROBE sense line. When bit 8 goes through a low to high to low cycle, the data at the input port is valid. If 8 bits of tape data are required, it is necessary to connect the strobe sense line to either another input port pin or to some other monitor line, such as an interrupt or serial input line, which can be tested under soft- ware control. Mechanically, I used a piece of 0.100 inch (0.025 cm) aluminum sheet bent into a U-shape, with an inside, bottom width dimension of 1 inch (2.54 cm). I used a small piece of clear Plexiglas as a hold-down device for the tape as it passed over the reader photocells. Further improvements can be added, such as a motor- driven, pinch-roller pull-through, but I have had no problems when pulling the tape through by hand. As a mat- ter of fact, I can stop pulling at any time, since the strobe pulse is speed insensitive. I plan to eventually add a hand crank and a take-up reel to avoid the great piles of tape that end up on the floor after loading some of my larger programs. To generate the required illumina- tion, I used an automotive lamp (type 211) mounted 3 inches (7.5 cm) above the photocells. Running the lamp on 5 V provides a good, uniform source of light, although it draws about 1 A of current. This entire project took only 3 evenings to design and construct, and the $15 price tag was a bonus. If you are still limited to 10 characters per second with your Teletype reader, you should seriously consider this high-speed paper-tape reader. ■ 120 September 1979 © BYTE Publications Inc + 5V +5V i .IOOK O^M>^i IOOK ^'|4 m + 5V AAAAAAAA \ IOOK (8) MRDI50 ^ TYPICAL FOR 8 PHOTOTRANSISTORS + 5V 13 14 DS2 DI-0 CLEAR DO-0 DI-2 DI-3 IC2 8212 DO-2 DO-3 DI-7 DO-7 DSl MD STROBE m \ V.^Sf' 2N3904 [>o^h— ^ II 5|\ 6 9|>s. 8 ^ /77 rh IOK |>oS -o -o o -O bit £> ) TO INPUT PORT OF PROCESSOR -Obit -o -| > BIT 8 -j ^> STROBE -| ^> STROBE IC TYPE + 5V GND 2 1 8212 7414 24 14 12 7 Figure 3: Schematic diagram of the paper-tape reader, which is capable of 400 characters per second. September 1979 © BYTE Publications Irtc 121 Bock Reviews Microcomputer-Based Design by John B Peatman McGraw-Hill Book Co, New York 1977 540 pages hardcover $26.95 Microcomputer-Based Design by John B Peatman is a combination text and reference book aimed at engineers who wish to learn how to design systems using microprocessors. It is written not in a dull, dry tone, but rather in a light style. The minimum required background for this text is a rudimentary knowledge of logic (ie: transistor-transistor logic gates and flip-flops) and the basic concepts of computer programming. The book develops hardware and software design skills upward from that point to a practical and useful level. A key feature of this book is the logical, lucid presentation of arguments present in the many illustrated design decisions. Microcomputer-Based Design is divided into 7 chapters and 6 appen- dices. The chapters are fairly com- plete, in-depth entities and each con- tains a set of practical design pro- blems and additional references. The references may be difficult to find for readers without access to an engineer- ing library since many of the references are articles in engineering journals or manufacturers' applica- tion notes. Chapter 1 is an overview of microcomputer applications focusing primarily on the distribution of "in- telligence" to instruments and tools. Chapter 2, "Microcomputer Registers and Data Manipulation," includes a brief discussion of number- ing systems and the various, com- monly encountered modes of address- ing. This is followed by a good presentation of machine language in- structions, assembly language, and assembly language programming techniques. Chapter 3 considers computer hardware organization. Several dif- ferent philosophies of commercially available microprocessor families are described. The characteristics of various logic families are considered with an eye towards interconnection compatibility. Bus structures and their electronic implementation are described in some detail. Flags, inter- rupts, direct memory acess control and programmable timers are also described with examples. Chapter 4 reviews the various characteristics of memory com- ponents and systems. Included are sections on the implementation of main power failure battery backup systems and floppy disks. Chapter 5 examines peripherals. There are sections on input/output control and handshaking, timing and buffering. There are also discussions of specific common microcomputer peripherals: keyboards, photo- transducers, circuit testers, analog-to- digital and digital-to-analog con- verters, pressure transducers, optical 122 September 1979 «-> BYTE Publications Inc Circle 328 on inquiry card. *0^wyou«s!2!£5£i \m vusivej \ \ 0\sH OP WthBOri gjnal Author 2» „ r, futures ■ • Eft onlv s4B ! 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When the user receives the program in the mail on cassette, it is loaded into the computer which will automatically make a Disk file of the program. □ CP/M & C BASIC for the TRS-80® CP/M Includes: MOVCPM, STAT, PIP, Dump, DDT, ASM (8080), ED, plus 6 user manuals. CP/M $160.00 C Basic-2 Includes: XREF2, CBAS2, and manuals. C BASIC 2 „ $99.95 it; 2 LEVEL III BASIC for TRS-80®. Special $39.99 □ TELCOM - Telecommunications for the TRS-80®. $29.95 Telecommunications for the TRS-8(i*allows one TRS-80® to communicate with another through the RS-232-C over the phone line. B TRS-i Orders received by 6:00 p.m. shipped next day on Master Charge, Visa, Money Order. ire 14 days to r~" ' Certified Check or Money Personal Checks require 14 clear. No C.O.D. Collect calls not accepted. All Hardware warranted for 90 days except Radio Shack equipment which is warrant- ed through Radio Shack. Software guaranteed for replacement only. Prices subject to change without notice. Automated Computer Software service (615) 244-2798 Division of Jnmputei World 625 Main Street . Nashville, TN 37206 NC. Send Check or Money Order payable to — SOFTWARE • P.O. Box 60097 Nashville, TN 37206 Quan. Description Unit Price Total HAND TENN LING CHARGE $1.50 RES. ADD 6% SALES TAX TOTAL □ Check □ Money Order □ MasterCharge □ Visa Card No. Exp. Date- Name Address City _ State Zip- Circle 7 on Inquiry card. 123 WE ARE KNOWN FOR OUR PROMPT, COURTEOUS SERVICE TELETYPE MODEL 43 ■ 4320 AAA (TTL interface) $985 ■ 4320 AAK (RS232 interface) $1,085 with transformer to operate on 50Hz, 220v, i nstal led inside cabinet add $50 We stock paper and ribbon for the Teletype Model 43 DEC LA 34 $1,259 KSR dot matrix printer. Provides variable line and charac- ter spacing and variable width paper. HAZELTINE 1500 (assembled only) $945 1510 $1,085 with 50Hz, 220v current adaptation $100 also available with Danish, German or French character sets add $60 INTERTUBE SUPER BRAIN $2,885 Dual Z80, dual floppy, double density, 64K RAM, 4Mhz., CP/M, FORTRAN, COBOL, BASIC, Assembler Language. Contained in Intertube II. INTERTUBE II $800 MARINCHIP SYSTEMS M9900-CPUS-100 COMPATIBLE. Network operating system, PASCAL, Extended precision commercial BASIC, FORTH, META & applications pack- age. Complete kit and DISCEX software $550; Assembled $700. We configure systems to meet your budget & your needs. Hard Disk interface (with software) available. IMS MEMORY, 16K Fully static, 250 ns $346 TEI S-1 00 Mainframes 12 slot — MCS 112 $433 22 slot — MCS 122 $609 These mainframes are completely assembled, tested and contain everything required for plug-in operation. TARBELL Floppy Disk Controller $255 Other Tarbell products available. KONAN HARD DISK CONTROLLER $1,550 S-100 compatible, plugs into S-100 mainframe. Controls 1-4 disk drives. FUJITSU HARD DISK $5,700 50 megabytes of unformatted data in a single, removable cartridge. IMS 5000 SERIES, COMPLETE Z80 SYSTEM $2,170 2 I/O ports, 1 K EPROM bootstrap loader, double density, dual 5Vt " disks, S-100, 12 slot mainframe. A new rising star! No waiting. PER SCI FLOPPY DISK DRIVES 299 DUAL DISK, 2 Sided $1,495 277 DUAL DISK, Single Sided $1,210 1170 CONTROLLER Single/Double Density $1,015 2142 CABINET & POWER SUPPLY for 277 $300 2149 CABINET & POWER SUPPLY for 299 $390 MODEM: "THE CAT" from Novation $190 Originate/Answer. 300 baud. TO ORDER: We ship within 24 hours after receipt of certified check, money order or cashiers check. Credit cards: add 4%. Personal checks: allow ten days. $12 shipping for ter- minals. $3 tor memories and modem. New York residents include sales tax. Prices and availability subject to change without notice. We have no reader inquiry number. Please call or write. johnd. OWENS ASSOCIATES inc. 12 SCHUBERT STREET STATEN ISLAND, NEW YORK 10305 DAY, EVENING, WEEKEND, HOLIDAY CALLS WELCOME! (212)448-6283 (212)448-6298 displays, relay drivers, syn- chromotors and printers. Finally, there are sections on universal asyn- chronous receiver-transmitters (UARTs), line drivers, the HPIB-IEEE 488 bus and self -test hardware. Chapter 6 describes the various op- tions that exist in hardware and soft- ware development packages from prototyping boards to disk-based operating systems. There is also a brief discussion of high-level languages for microcomputers. Chapter 7 describes in detail the algorithms for solutions to several common microcomputer software problems. Algorithms are described to read and to parse a functional keyboard input, self-test routines and number system conversion and manipulations. Real-time program- ming constraints are also considered. The set of appendices describes the characteristics of specific microcom- puters. Each appendix covers the ar- chitecture and organization of a par- ticular processor integrated circuit. The rest of the integrated circuit set (memory, input/output, etc) is also briefly covered. Appendices are in- cluded on the 4004, F8, 8080, 6800, COSMAC, and PPS-8 processors. It is refreshing to see that these appen- dices are more than just a reprinting of the manufacturer's specification sheets. On the negative side, there is a disturbing absence of discussion of any of the high-performance in- tegrated circuits that were certainly available when this book was written. There is also inadequate treatment given to bit-slice and microprogramming techniques. Soft- ware development by emulation is also omitted. The balance is, however, overwhelmingly positive. This is a text which starts off quietly, never grows dull, and yet contains a great deal of substance. There are sec- tions on using esoteric devices like first in, first out stacks (FIFOs) that I have previously never seen in a design text. It is a welcome development. I recommend this book to advanced experimenters, undergraduate engineering students and practicing engineers. ■ Ira Rampil 2217 Cypress Way Apt 15 Madison WI 53717 124 September 1979 © BYTE Publications Inc Circle 349 on inquiry card. BYTE September 1979 125 ® VECTOR PACKAGING SYSTEMS SAVE TIME & MONEY! New ANYDIP 8804, $21.95 8802-1, $21.95 S-100 CARDS Five models available. Universal tinned buses, pads or plain. 0.042 inch diameter holes on 0.1 inch grid for mounting anything anywhere. For interface, memory, breadboardmg. R681-2 RECEPTACLE FITS 8803 MOTHERBOARD Model R681-1 has 0.062 inch long 0.025 inch square tails. TEFZEL* Insulation Wire Wrapping Tools: u. s. & foreign patents Up to 4X faster. . Heavy insulation. P184-4T with NiCad batteries, recharger, 100' daisy-chain wraps of wire: $105.00. P184 with 100 feet of wire, $30.00. BEAUTIFUL VP2 ENCLOSURE-supplied completely assembled for packaging. S-100 based systems. Clear aluminum with blue vinyl finished slide-off sides, top, and perforated bottom cover; heavy chassis plate, removable front and real panels, adjustable connector /Motherboard mounting struts, card guides (plastic guides supplied uninstalled). VP2, $159.00. VP1, cards mount perpendicular to front, $163.00. BP17-9 accessory back panel, $10.95. Low-noise model 8803 S-100 Motherboard not shown. Eleven positions ready for connectors. Glass epoxy, solder masked etched circuitry for passive and active termination, twelve tantalum capacitors and instructions. $29.50. *DuPont trademark Prices subject to change without notice. Send for complete data. Packaging systems for other card sizes and systems, rack mounting are available VECTOR ELECTRONIC COMPANY, INC. 12460 Gladstone Avenue, Sylmar, CA 91342 telephone (213) 365-9661 ; TWX (910) 496-1539 ad number 627901 See us at WESCOW Booth 1216-18. Programming Quickies Day of Week and Elapsed Time Programs W B Agocs, Dept of Physical Sciences Kutztown State College, Kutztown PA 19530 The day of the week, the number of elapsed days of a year, and the number of days between 2 dates are infor- mation that is required frequently in various types of analyses. The procedure to determine the day of the week uses Zeller's congruence: [~ Y 1 C + 4 4 - -2C}MOD7 d = {[2.6m-0.2] + K + Y + The term m is the month number minus 2. If the month is January or February, m is 11 or 12 of the previous year. K is the day of the month; C is the century, and Y is the year of the century. The value of the square brackets is defined as the integer part of the result of evaluating the interior expression. Day of Week From Date The program is so written that corrections to month 11 or 12 of the previous year are made automatically if the month is January (1), or February (2). The program is shown in listing 1. Century selection could have been in- corporated, but the program is designed for the 20th cen- tury. Once the number of the day of the week is obtained (with Sunday being day 1), the date and the day are printed. Matrix Elapsed Time Determination The use of a 12 by 31 matrix seems to be the most logical method for determining the elapsed days of a year, the remaining days in a year, and the day interval between 2 dates. The program for such a determination is shown in listing 2. The MAT A = CON statement in line 50 sets each element of the matrix equal to 1. The subroutine in statements 440 thru 540 enters 0s into the matrix elements which correspond to the months with less than 31 days, and then fills the matrix elements with the date's numerical location in the year. Thus on return from the subroutine, the days elapsed may be printed between statements 180 and 190, or between statements 400 and 410 if desired. Leap year corrections are made at lines 270 and 440. Finally, if the interval between the 2 dates is less than or greater than a year (as determined by statement 100), the correct year increment is made in statements 230 and 280. The total time interval is determined in statement 180 or 410, and the result printed at statement 190. Text continued on page 129 126 September 1979 © BYTE Publications Inc Circle 377 on inquiry card. Bob admits he thought his computer had reached the limit of its capabilities. Then he discovered the BASIC Compiler from Microsoft. "It's incredibly fast" he boasts. "Nothing was as fast as my Microsoft BASIC inter- preter—yet this new compiler is actually 3-10 times faster. "And that's not all;' he beamed. "My compiler has the same language features as Microsoft 5.0 BASIC and runs in my 32K CP/M system:' Bob says, "When Microsoft comes out with a new product, I know it's got to be good. And this BASIC Compiler is the wizard I've been waiting for. "At last, I can generate relocatable machine language modules from my Microsoft BASIC programs— machine code that's highly optimized. And because the Microsoft macro assembler and loader come with the BASIC Compiler, BASIC programs are easily linked to assembly language subroutines or Microsoft FORTRAN and COBOL programs. Just like the pros!' smiled Bob. "What's more, the compiler generates a fully symbolic listing of the machine language that's generated — a great way for me to learn assembly code on my own!' Bob believes in giving credit where credit is due. "Microsoft turned my BASIC com- puter into a genuis for $395, but I was smait enough to recognize a good thing immediately'.' If you want to get the most out of your computer and your BASIC programs, ask for more information on the Microsoft BASIC Compiler. We know you'll compliment your- self on a very smart move. 10800 N.E. Eighth Suite 819 Bellevue, Washington 98004 206/455-8080 Telex 328945 We set the standard. BYTE September 1979 127 BISYNC- 80/3780 BRINGS IBM BINARY SYNCHRONOUS COMMUNICATIONS CAPABILITY TO THE 8080, 8085, AND Z80 MICROCOMPUTER APPLICATIONS: DISTRIBUTED DATA PROCESSING REMOTE JOB ENTRY (RJE) CICS ACCESS BATCH DATA TRANSMISSION / / / IBM S/360 CPU IBM S/370 CPU IBM 30xx CPU / s 8080, 8085 or Z80 with BISYNC-80/3780 / Synchronous Modem N IBM 2770, 2780, or 3780 Terminals \ STANDARD FEATURES: \ Word Processing, Point of Sale Equipment \ s \ Other Microcomputers With BISYNC-80/3780 FULL FUNCTION IBM 3780 EMULATION 1200-9600 bps POINT-TO-POINT OR SWITCHED LINE EBCDIC TRANSMISSION CODE WITH AUTOMATIC TRANSLATION TO AND FROM ASCII SEND AND RECEIVE STANDARD DISK FILES RUNS WITH CP/M tm OPERATING SYSTEM AVAILABLE FOR S-100 AND TRS-80 SYSTEMS USE WITH MOST 8251-BASED I/O BOARDS REQUIRES NO INTERRUPTS This professionally written and documented software can integrate your microcomputer into the world of large scale data processing on IBM compatible equipment. You can have the distributed processing power of your microcomputer plus IBM terminal capability! Price $295, includes documentation and software on CP/M diskette. Optional RJE Console Support software - $95. Optional Printer Driver software - allows receiving data directly to printer instead of diskette - $95. Synchronous I/O board and all required cables - $345 for S-100; $545 for TRS-80. Documentation - $15. Complete system packages available. ^^^^*" 104 Morris Avenue ■ P.O. Box 335 Q Friendsville, MD 21 531 ■ (301)746-5888 128 BYTE September 1979 Circle 211 on inquiry card. Text continued from page 126: The matrix procedure, with correction for appropriate holidays, can be used in conjunction with stock market studies when knowledge of the market day interval is desired, or when determining if a particular date is a market trading day. Listing 1: BASIC program for determining the day of the week from the date using Zeller's congruence. 0010 PRINT "ZELLER'S CONGRUENCE-DAY OF WEEK FROM DATE." 0020 PRINT "WHAT IS THE DATE-MONTH, DAY, YEAR?" 0030 INPUT M,D,Y 0035 LET Y1 =Y 0037 LETM1 =M 0040 IF(M=1)OR(M = 2)THEN 60 0050 GOTO 105 0060 IF M = 1 THEN 90 0070 LET M = 12 0080 GOTO 100 0090 LET M = 1 1 0100 LET Y = Y-1 0102 GOTO 110 0105 LET M = M-2 0110 LET D1 =INT(2.6.M-.2) + D + (Y-1900)+INT((Y-1900)/4) 0115 LET D1 =D1 + INT(19/4)-2*19 0120 LET D1 =D1-INT(D1/7).7+ 1 0125 PRINT "D1 =";D1 0130 ON D1 GOTO 140, 150, 160, 170, 180, 190, 200 0140 LET A1$ = "SUNDAY" 0145 GOTO 210 0150 LET A1$ = "MONDAY" 0155 GOTO 210 0160 LET A1$ = "TUESDAY" 0165 GOTO 210 0170 LET A1$ = "WEDNESDAY" 0175 GOTO 210 0180 LET A1$ = "THURSDAY" 0185 GOTO 210 0190 LET A1$ = "FRIDAY" 0195 GOTO 210 0200 LET A1$ = "SATURDAY" 0210 PRINT "FOR ";M1;"/";D;'7";Y1;" IT IS ";A1$ 0220 PRINT 0230 END Listing 2: BASIC program for using a matrix to determine the elapsed time between 2 dates. 0010 PRINT "MATRIX DETERMINATION OF DAYS BETWEEN DATES." 0020 PRINT "PROGRAMMED APRIL 15, 1979;W. B. AGOCS." 0030 DIMA(12,31) 0040 DCL S(A()) 0050 MAT A = CON 0060 PRINT "WHAT IS THE FIRST MONTH, DATE, YEAR?; EXPRESS NUMERICALLY AS 11, 15, 1978." 0070 INPUT M1, D1, Y1 0080 PRINT "WHAT IS THE NEXT MONTH, DATE, YEAR?" 0090 INPUT M2, D2, Y2 0100 IF Y2-Y1 =0THEN 120 0110 GOTO 220 0120 IF Y1/4-INT(Y1/4) = 0THEN 150 0130 GOSUB450 0140 GOTO 160 0150 GOSUB440 0160 LETS1 =A(M1, D1) 0170 LET S2 = A(M2, D2) 0180 LETS3 = S2-S1 0190 PRINT "INTERVAL BETWEEN ";M1;"/";D1;"/";Y1; 0195 PRINT " AND ";M2;"/";D2; , 7";Y2;" IS "; 0200 PRINT S3;" DAYS." 0210 GOTO 580 0220 LET S = 0230 FOR l = Y1 + 1 TO Y2-1 STEP 1 0240 IF l/4-INT(l/4) = THEN 270 0250 LETS = S + 365 0260 GOTO 280 0270 LETS = S + 366 0280 NEXT I 0290 IF Y1/4-INT(Y1/4) = THEN 320 0300 GOSUB 450 0310 GOTO 350 0320 GOSUB 440 0330 LETS1 =366-A(M1,D1) 0340 GOTO 360 0350 LETS1 =365-A(M1,D1) 0360 IF Y2/4-INT(Y2/4) = THEN 390 0370 GOSUB 450 0380 GOTO 400 0390 GOSUB 440 0400 LETS2 = A(M2,D2) 0410 LETS3 = S + S1 +S2 0420 GOTO 1 90 0430 REM SUB-ROUTINE 0440 LET A(2,29) = 0450 LET A(2,30) = A(2,31 ) = A(4,31 ) = A(6,31) = = A(11, 31) = = A(9,31) 0460 LET N = 0470 FOR 1 = 1 TO 12 STEP 1 0480 FOR J = 1 TO 31 STEP 1 0490 IF A(I,J) = 1 THEN 510 0500 GOTO 530 0510 LET N = N + 1 0520 LETA(I,J) = N 0530 NEXT J 0540 NEXT I 0550 RETURN 0560 PRINT 0570 PRINT 0580 PRINT "THE END." 0590 END ■ A Text Loader Routine Howard Berenbon 2681 Peterboro W Bloomfield MI 48033 Here is a useful program for the Motorola 6800 microcomputer. This subroutine allows the loading of ASCII text into the desired memory location directly from your terminal. It uses the Motorola MIKBUG monitor for character input and output. The subroutine may be entered beginning at hexadecimal address A060. To exit the program simply type a %. Hexadecimal Hexadecimal Address Code Mnemonic Comments A060 86 3F LDAA #$ 3F Load A with ? A062 BD EO 75 JSR CHAROUT Output ? A065 86 20 LDAA #$ 20 Load A with a space A067 BD EO 75 JSR CHAROUT Output space A06A CE - - LDX #$ Load index register with desired address A06D BD EO &LOOP 78 JSR CHARIN Input character A070 A7 00 STAA $ 00:X Store A indexed A072 08 INX Increment index register A073 81 25 CMPA #$ 25 Compare A with % A075 26 F6 BNE &LOOP Get another character A077 7E E0E3 JMP MIKBUG Return to MIKBUG ■ September 1979 © BYTE Publications Inc 129 A Model of the Brain for Robot Control Part 4: Mechanisms of Choice The essence of a hierarchy is that control is top-down. The ultimate choices are made at the top, and the goals selected at this level are decom- posed into action as they filter down The ideas presented in this article repre- sent the views of the author and not those of the Department of Commerce or the National Bureau of Standards. James Albus Project Manager National Bureau of Standards United States Dept of Commerce Washington DC 20234 through the various levels of the hierarchy. For the purposes of our discussion, we will define the highest level H function in the behavior- generating hierarchy of the human brain as the will. For centuries philosophers and theologians have debated the nature of the will, particularly the question of whether humans have "free" will (ie: the freedom to choose goals) or whether all choice is merely a reflex- ive or predestined response to the en- vironment. We shall not presume to deal with this question here, other than to suggest what types of inputs are available to this highest level goal selection module. By definition much of the input to the highest level behavior-generating module must come from the highest level sensory-processing module. TALK OBSERVATION D 111 N Z a. < uj X 2 LiJ UJ Figure 1: An action (such as a person talking to a flower) may be recognized as either familiar or unfamiliar. If an action is noted as familiar, then it can be considered unnoteworthy and will be ignored. If the action is considered deviant, further processing will take place to determine reactions to the action. 130 September 1979 © BYTE Publications Inc $3,995 Million-Character Computer System One- Year Transferable Warranty $3,995 SEE System 6684 Unique Standard Features CPU integrated into Diskette Cabinet with peripheral ports in rear of cabinet 1 4 Full communications ports RS232 or 20 mA/60 mA CL; 75 to 19,200 bits/sec. $4,995 SEE System 6784 Unique Standard Features CPU integrated into video terminal cabinet with peripheral ports in rear Video has 16 programmable function keys, 128 high resolution characters with graphics, numeric keypad, reversed video, full editing, 24 x 80 display Standard Features on All Systems • Central Processing Unit with 12 slots; 2 MHz (ex- pandable to 4MHz with pipelining architecture) • 8 Free Slots for expansion; capacity for 442,368 characters of memory within standard chassis • 49,152 characters of 200 ns random access memory; 150 ns memory optional • 8 vectored interrupts; all input and output is interrupt driven • 1.2 million characters, double sided, dual 8" diskettes. IBM 3470 compatible • Printer controller; Centronics compatible • Magnum BASIC. Extremely fast business BASIC with full editing capabilities, print using, sequential and random files, integer and floating point arithmetic with up to 16 digits precision; N-dimensional matrices and much more A superset of Microsoft 16K extended disk BASIC • Interactive conversational macro assembler and editor for 6800 family microprocessors • One-year transferable limited warranty on parts and labor for all SEE hardware • Guaranteed 24-hour turn-around time on repairs Optional Features on All Systems • Up to 64 interconnected, intelligent terminals with no degradation of response time. Each is a stand alone CPU. True distributed processing • Expandable to 12 MB of 150 ns RAM for each terminal • Up to 64 RS232 ports with full communications. Talks to any peripheral or CPU with RS232 interface • Expandable to 4 MB of diskette storage • Up to 660 MB hard disk storage with removable modules • ANSI standard 10.5 inch tapes (1600 BPI) • 11 MB cartridge tape system • Matrix and word processing printers from 55 CPS to 1400 LPM • Choice of 6809 and/or 6512 CPU board with speed of up to 4 MHZ with 1 50 ns memory • Interactive relocatable macro assembler, development system and DOS for 6502 and 6512 microprocessors. Can assemble source programs up to 2 MB long • PASCAL compiler • FORTRAN compiler • BASIC compiler • 6809 Macro Assembler • Powerful word processing software • Comprehensive business software, incl. General Ledger, Accounts Receivable, Accounts Payable, Inventory, Pay- roll, etc. Quantity discounts to bona fide dealers, OEMS, and schools Special configurations and modular shipment available A few distributorships available in the United States and other countries Circle 350 on inquiry card. SYSTEMS ENGINEERING ENTERPRISES 1749 Rockville Pike, Rockville, Maryland 20852 (301)468-1822 BYTE September 1979 131 This is the level at which the overall result of the entire sensory processing operation is evaluated as being good or bad, rewarding or punishing, satis- fying or frustrating. In humans, this function is performed by what are commonly called the emotions. It has long been recognized that emotions play a crucial role in the selection of About the Author Dr ]ames S Albus worked for NASA from 1957 to 1972 designing optical and electronic subsystems for over 15 spacecraft, and for one year managed the NASA Artificial Intelligence Program. Since 1973 he has been with the National Bureau of Standards where he has received several awards for his work in advanced computer control systems for in- dustrial robots. He has written a survey article on robot systems for Scientific American (February 1976) and his Cerebellar Model Arithmetic Computer won the Industrial Research Magazine IR-100 Award as one of the 100 most significant new products of 1975. He is also the author of People's Capitalism: The Economics of the Robot Revolution which is published by New World Books, 4515 Saul Rd, Kensington MD 20795. behavior. We tend to practice that which makes us feel comfortable and avoid what we dislike. Our behavior- generating hierarchy normally seeks to prolong, intensify, or repeat those behaviors which give us pleasure or make us feel happy or contented. We normally seek to terminate, diminish, or avoid those behavior patterns which cause us pain, or arouse fear or disgust. In the past 25 years it has become known that the emotions are generated in localized areas, or com- puting centers, in the brain. For ex- ample, the posterior hypothalamus produces fear, the amygdala gen- erates anger and rage, the insula com- putes feelings of contentment, and the septal regions produce joy and ela- tion. The perifornical nucleus of the hypothalamus produces punishing pain, the septum pleasure, the anterior hypothalamus sexual arousal, and the pituitary computes the body's response to danger and stress. These emotional centers, along ASCII encoded keyboards as low as $65* The RCA VP-601 keyboard has a 58 key typewriter format for alphanumeric entry. The VP-61 1 ($1 5 additional*) offers the same type- writer format plus an additional 1 6 key calculator type keypad. Both keyboards feature modern flexible membrane key switches with contact life rated at greater than 5 million operations, plus two key rollover circuitry. A finger positioning overlay combined with light positive activation key pressure gives good operator "feel", and an on-board tone generator gives aural key press feedback. The unifized keyboard surface is spillproof and dustproof. This plus the high noise immunity of CMOS circuitry makes the VP-601 and VP-61 1 particularly suited for use in hostile environments. The keyboards operate from a single 5 volt, DC power supply, and the buffered output is TTL compatible. For more information contact RCA VIP Marketing, New Holland Avenue, Lancaster, PA. Telephone (71 7) 291 -5848. 'Optional user price. Dealer and OEM prices available. with many others, make up a com- plex of about 53 regions linked together by 35 major nerve bundles. This entire network is called the lim- bic system. Additional functions per- formed in the limbic system are the regulation of hunger and thirst per- formed by the medial and lateral hypothalamus, the control of body rhythms such as sleep-awake cycles performed by the pineal gland, and the production of signals which con- solidate (ie: make permanent) the storage of sensory experiences in memory performed by the hippo- campus. This last function allows the brain to be selective in its use of memory by facilitating the permanent storage of sensory experiences to which the emotional evaluators attach particular significance (eg: close brushes with death, punishing experiences, etc). Input to the limbic system emo- tional centers consists of highly pro- cessed sensory -data such as the names of recognized objects, events, rela- tionships, and situations, such as the recognition of success in goal achieve- ment, the perception of praise or hostility, or the recognition of gestures of dominance or submission transmitted by social peers. These in- puts are accompanied by such modi- fier variables as confidence factors derived from the degree of correlation between predicted and observed sen- sory input. Sensory processing at the level of the emotions is heavily influenced by contextual information derived from internal models and expectations at many different levels in the proces- sing hierarchy. If a painful stimulus is perceived as being associated with a nonfear producing source, we may attack the pain causing agent. If, however, the perceived source of pain also induces fear, we may flee. Similarly if an observed event such as a person talking to a flower is per- ceived as deviant, then this input to the emotions, along with other recognized qualifier variables such as the person is a) eccentric, b) retarded, or c) dangerously psychotic, will cause the emotions to output a) amusement, b) pity, or c) fear, respectively. Amusement input to the behavioral goal selecting module may lead to laughter, poking fun, or ridicule. Pity input to the will may 132 September 1979 © BYTE Publications Inc Circle 334 on inquiry card. WHEN THE FUN AND GAMES ARE OVER, y <, ush <.uidn t have to gamble on your microcomputer's ability to get down to business. You won't with Outpost 1 1. It's a serious unit with quality components: Cherry, full ASCII key- board; Setchell-Carlson CRT, 24 x 80 characters, 7x9 dot matrix; inverse, grey, blink; form generation characters; Shugart floppy disk drives; M6800 CPU; 32 k bytes RAM; glass-epoxy PC boards, manufactured and tested to Mil Q 9858-A; entire unit 1 00-hour burn in tested; IC's tested to Mil P 883; I/O interrupt prioritizing structure; soft- sectored disk format; business BASIC; FLEX 2,0; TSC BASIC; self diagnostics; software development packages; etc; etc; etc. All this and more at only $2,595, suggested retail price. See Outpost 1 1 at a dealer iistec or w rite us for the name of a dealer near you. 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TWX 81 0-591 -5229 Circle 362 on inquiry card. evoke a behavioral pattern of sym- pathy. Fear may evoke an attempt to secure medical or psychiatric treat- ment, or incarceration. If, however, a person talking to a flower is recognized as perfectly nor- mal, then the emotions will give no indication that the event is particu- larly worthy of attention, or that there exists any need to deviate from whatever behavior is presently being executed. These relationships are described graphically and symboli- cally in figure 1. In this model the standards of nor- malcy and deviance are clearly in the eye of the beholder, or at least in the expectations and beliefs stored in the processing-generating hierarchy. In many ways the emotional evaluators are even more dependent on internal beliefs than externally observed facts. This is particularly true in the case where a person's belief structure dis- counts the reliability or moral worth of the physical senses, as is characteristic of philosophical con- structs derived from gnosticism or asceticism. Thus the emotions, just as any other sensory processing module in the brain, simply compute a G func- tion on the D vector that they input to produce the Q vector that they output. In simple creatures the emo- tional output vector may be restricted to a few components such as good- bad, pleasure-pain, etc. In higher forms the emotional output is a highly multidimensional vector with many faceted components such as love, hate, jealousy, guilt, pride, disgust, etc. Part of this Q output may simply produce feelings (ie: joy, sadness, excitement, fear, etc). However, most of the Q output directly or indirectly provides F input to the highest level H function, the will. Output from the emotional centers is known to be of two types: one con- sists of signals on nerve fibers; the other consists of hormones and chemical transmitters which convey their messages (Q vector values) via fluid transport mechanisms. What the G and H functions of the emotions and will are, and where they come from is a matter of hot dispute. One recent theory proposed by sociobiology is that they are gene- tically determined, derived from in- formation stored in the DNA molecule, as the result of millions of years of natural selection. This theory argues that innate behavior-selecting mechanisms have evolved so as to maximize the Darwinian fitness (the expected number of surviving off- spring) of their possessors. The incidence of behavior in many different species from insects to birds to mammals corresponds closely to mathematical predictions derived from genetics and game-theory analyses of strategies for maximizing the probability of gene propagation. Even cooperative or altruistic behavior such as that of the worker bee, and ritualized behavior in animal contests and courtship, can in many cases be explained by genetic arguments. However, the evidence for this theory is much stronger for insects than for higher forms, and the opinion that human emotions are transmitted genetically is not widely held. A competing theory put forward by behaviorists is that in higher forms the evaluator functions of the emo- tion and the selector functions of the will are mostly learned, perhaps even CROMEMCO 20% DISCOUNT System III System II System II with 10 Meg Disk NORTH STAR 16% DISCOUNT Horizon I — 32K Ram asm Horizon I — 16K Ram asm Horizon I - 32K Ram kit Horizon I to Horizon 2 32K Ram asm VECTOR GRAPHICS 20% DISCOUNT Vector MZ-2 (630K disk) 48K Ram 3750 List Our Price 5990 4792 3990 3192 9995 7996 or more) 2099 1763 1899 1595 1849 1553 450 378 659 525 Soroc IQ120 Perkin Elmer Bantam CRT 995 996 Intertube II 995 Integral Data IP125 799 Escon Selectric Interface 496 NEC 551 0RO Word Processor Printer 2900 3000 790 750 750 699 422 2450 Professional A/r, A/p, Ledger, Payroll, Medical Billing soft- ware with customization available. Send for our catalog — Some prices are too low to quote. SARA TECH COMPUTERS P.O. Box 692 400 Base Venice, FL 33595 (813)485-3559 PEOPLES' CAPITALISM The Economics of the ROBOT REVOLUTION by JAMES S. ALBUS Jeffersonian democracy applied to the Second Industrial Revolution An exciting new economic philosophy with a plan to: • Avoid conflict between human and robot workers • Create an everyman's aristocracy based on robot labor • Increase productivity and cure in- flation • Bring affluence into harmony with ecology After reading it you will no longer be sure that Utopia is beyond our grasp. Now available from $4.75 delivered NEW WORLD BOOKS softcover 451 5 Saul Road, Kensington, MD 20795 134 Seplember 1979 © BYTE Publications Inc Circle 320 on inquiry card. Circle 282 on inquiry card. INTERTEC'S INTE3TU3E 1 1 VIDEO DISPLAY TERMINAL ATTENTION OEM's and DEALERS: Your customers request InterTube terminals for one simple reason. They outperform the competition so well that it's foolish to consider any other terminal. Add to that InterTube's rugged design which insures you of the reliability that brings customers back. And modular design engineering that makes service a snap! But best of all, the InterTube is readily available. Just a quick call and you'll have units in stock. Immediately! And our scheduled delivery program will help you keep them in stock. Good margins, good service, good delivery. Simple? You bet it is! InterTube II dealerships and OEM agreements are now available in many areas. Contact us today and start selling from stock tomorrow! The InterTube II Video Display Terminal is truly representative of the latest state-of-the-art advances in microprocessor technology. Its basic teletypewriter compatability combined with its numerous "smart" terminal features satisfy the universal requirement for a low-cost, high performance video terminal. You get everything you need. An upper and lower case character set displayed on a sharp 8 X 10 dot matrix. A full 24 line by 80 character screen. A status line displayed in reverse video. A complete ASCII keyboard with an 18-key numeric pad. You get full cursor addressing, automatic repeat of all keys and individual backspace and shiftlock keys. Plus, a graphics mode for easy design and display of all types of forms. And an RS-232 serial printer port. And you get everything your operators need to make their jobs a pleasure. A hooded display that cuts glare and gives extra privacy. A wide bandwidth monitor for sharp images everywhere on the screen. Below-the-line character descenders to make reading easier. A programmable white-on-black or black-on-white display and a self-test mode for easy maintainability. You get high powered text editing with such features as character and line insert/delete, full and/or partial block transmit, programmable end-of-line terminators, and protected fields. All standard! And all for a retail price you won't believe . . . only $995. Incredible! INTE3TEC DATA SY5TEMS. mb Corporate Headquarters: 2300 Broad River Road • Columbia, South Carolina 29210 • 803 / 798-9100 • TWX: 810-666-2115 Circle 180 on inquiry card. BYTE September 1979 135 imprinted, during the early years of development. Certainly many of the emotional evaluations and behavior selection rules in the human brain are culturally determined, derived from religious teachings defining good and evil, or from social conventions defining duty, fairness, etiquette, and legality. These fundamental rules of opinion and behavior are instilled in the young by parents, educators, and religious and state authorities. They are reinforced throughout life by peer group pressure, as well as by church and civil sanctions. There are, of course, many persons who would disagree with both of these theories. Perhaps the most widespread opinion (which until recent years was virtually unchal- lenged) is that the human will and its emotional evaluator inputs are non- mechanistic in nature and therefore unknowable in some fundamental sense. Many would even claim that emotions and will are subject to, or controlled by, spiritual and super- natural forces. For example, the doc- trine of original sin states that the highest level behavior selecting mechanism, the human will, is basically defective because of the disobedience of Adam and Eve, and except for divine intervention is under the power of evil or satanic forces. The literature surrounding the age old controversy over free will versus predestination centers largely on the role of the Divinity (or the stars, or fates) in the determination of human behavior. Most cultures view the conscience (ie: the emotional evaluator for right and wrong or good and evil) as a divine gift or manifestation of the indwelling of the spirit of God. Clearly the emotions and will are a very basic (some would say prim- itive) and compelling part of our behavioral mechanism. Carl Sagan calls them the Dragons of Eden. Humans are often driven, sometimes beyond rational justification, to heroic feats of courage or physical endurance by the behavior rules of duty or the emotions of love, pride, guilt, jealousy, and hate. Whatever their origins, the G func- tions of our emotions and the H func- tions of the will can be modeled. They are rule based, and the rules are, for the most part, clearly defin- ed. In many cases these rules are even written down as systems of moral philosophy, ethics, or rules of social behavior such as Emily Post's Book of Etiquette. Nothing so complex need be modeled for the highest level G and H modules of a robot for many years. Nevertheless, every robot needs some sort of highest level evaluator and goal selector function in order to ex- hibit any sort of autonomous be- havior. At what point in the spectrum of multidimensional sophistication we choose to dignify an evaluator function with the term emotion, or goal selection function with the term will, is not clear. What is clear is that simple approximations to the func- tions computed by the emotions and the will can be moduled by CMAC G and H functions operating on input vectors and computing output vec- tors. The degree of sophistication and complexity of the modeling is limited only by the ingenuity and resources of the modeler. The interdependency of the pro- cessing and generating hierarchies suggests at least 3 distinct modes of operation. INFINITE BASIC RELOCATABLE MODULES FOR THE TRS LEVEL II AND DOS SYSTEMS LOAD ANY OR ALL MODULES. FOR $49.95 THE CORE PACKAGE INCLUDES: 90 MATRIX PACKAGE oc Over 30 BASIC commands including: oo Matrix Read, Inverse, Transpose, and Identity. Simultaneous Equations! ! ! oo Add, Subtract, or Multiply Scalars, Vectors, or Multi- dimension arrays!!! oo Dynamically Reshape, Expand, Delete Arrays, Change arrays in mid-program. oo Copy array elements, set arrays to scalar, zero arrays, move arrays. °° Tape array read and write including string arrays. FOR $29.95 more get the oo BUSINESS PACKAGE oo oo Eliminate round-off error! I Multiple precision packed decimal arithmetic. 127-digit max. accuracy oo Binary search or sorted arrays. Insert new elements in sorted arrays!!! oo Automatic page headings, footings, and pagination. Includes forced end-of-page. oo Automatic hash for record retrieval!! And more for your professional packages. COMMAND PROCESSOR 'COMPROC for $19.95 (DOS only) Extend DOS-AUTO command to perform multiple steps either at power-up or as a user command Execute a script consisting of a sequence of commands or data from a BASIC command file. REMODEL + PROLOAD for $34.95 (Specify 16, 32, or 48K version) REnumberany section of a program, MOve program segments, DEIete program lines. Combine programs with renumber and merge. Load or save any portion of program from tape. DISK SORT PROGRAM 'DOSORT' for $34.95 (Specify 32 or 48K, minimum 2 disk system) SORT/MERGE multi-diskette sequential files. Multiple variables and keys. Includes machine language in-memory sorts, comparators and string handling. COPY SYSTEM TAPES with 'COPSYS' for $14.95 (Non-DOS) oo STRING PACKAGE oo Over 40 BASIC commands including: oo Left and right justify, truncate, rotate. Text justification. String centering. oo Delete or insert substring, Pack strings, Convert to upper or lowercase. oo Translate characters, Reverse strings, Verify function, Number of occurrences. oo Masked string searches for simple or array variables. Encrypt or decrypt strings. oo Compress/uncompress character string arrays to 6 bits or less per character. oo AND the famous RACET machine language SORTS. Multi- key multivariate and string. Sort 1000 elements in 9 sec!! FUTURE oo ADD-ON PACKAGES =» will include oo STATISTICS oo INPUT/OUTPUT aeGRAPHICS oo Attn: TRS Add-On OEM's: We can support your special hardware add-ons with direct BASIC commands. System Houses: We license System House usage of oo INFINITE BASIC oo modules. Check, VISA, M/C C.O.D. Calif, residents add 6% Telephone Orders Accepted (714)637-5016 WHEN ORDERING PLEASE ADVISE PUBLICATION SOURCE E" RACET COMPUTES -^ 702 Palmdale, Orange CA 92665 136 September 1979 © BYTE Publications Inc Circle 310 on inquiry card. $ 100 to $ 139 Off the TRS-80 Computers! You can believe a product is tops, when more than 100,000 owners have chosen it over its competition! That overwhelming acceptance has dropped production costs, and allowed us to make TRS-80 an even better value. $100 Off! 4K Level I This is the ideal beginner's computer system. Our manual makes learning programming in Level I BASIC a snap. Easily upgrades to Level II or more memory at any time. 26-1051 £ijl f\f\^ Was $599 in 1979 Catalog *k\j\j $139 Off! 16K Level II Level II BASIC is one of the most powerful microcomputer programming languages. Level II TRS-80 systems can be expanded to include printers, disk storage . and much more. 26-1056 JsO Jt f\ Was $988 in 1979 Catalog O^" TRS-80 Line Printer II Now — for hundreds of dollars less than you'd expect to pay — you can add line printer utility and convenience to your Level II TRS-80 system. This top quality impact-type printer doesn't require special paper — you can use inexpensive rolls (available at Radio Shack), continuous forms (original and up to two carbons) or single sheets. The 7x7 dot matrix head prints 50 characters per second; 80 characters on 8 inch lines. Also prints expanded (wider) characters that are ideal for headings under soft- ware control. Standard 9V2 inch wide continuous forms are kept in perfect alignment by non adjustable pins on platen. Includes Expansion Interface cable. 26-1154 $ 999 Radio /hack The biggest name in little computers A DIVISION OF TANDY CORPORATION • FORT WORTH, TEXAS 76102 OVER 7000 LOCATIONS IN NINE COUNTRIES "Retail prices may vary at individual stores and dealers Circle 318 on inquiry card. TRS-80 Line Printer II Interface Cable Now you can attach the Line Printer II directly to your TRS-80 Level II 16K system. No Expansion Interface required unless you plan to add mini disks or more memory. 26-1416 $59 * BYTE September 1979 137 Circle 161 on inquiry card. HAYDEN SETS YOUR SYSTEM STRAIGHT New! DESIGNING MICROCOMPUTER SYSTEMS (Pooch & Chattergy) Provides a wealth of information for building microcomputer systems. Also discusses numerous hardware aspects including microprocessor architecture, input and output ports, interrupt systems, programmable clocks, etc. #5679-6, $8.95 New! DATA COMMUNICATION COMPONENTS: Characteristics, Operation, Applications (Held) Contains over 150 schematic diagrams that illustrate the effective use of over 25 components in the design, modification or optimization of data communication networks. #5126-3, $14.95 New! BASIC MICROPROCESSORS AND THE 6800 (Bishop) Gives you two books in one: a basic guide to microprocessors for the beginner, and a complete description of the M6800 system for the engineer. #0758-2, $11.95 1980 Hayden Computer Calendar Will Be Available In October! • full-color original computer art • complete program for perpetual calendar • computer anecdotes Available at your local computer store! Hayden Book Company, Inc. 50 Essex Street, Rochelle Park, NJ 07662 Acting — The Task Execution Mode In the task execution mode the motor-generating hierarchy is com- mitted to a goal, which it decomposes into subgoals, sub-subgoals, and finally into action primitives. In this mode the sensory-processing hier- archy is primarily engaged in pro- viding feedback; first to aid in se- lecting the goal, then to steer the goal decomposition process, and finally to direct the output drive signals to the muscles (or actuators) so as to follow a success trajectory. Consider a simple, everyday goal such as the fixing of a leaking faucet. First, the sensory processing system must recognize the fact that the faucet is leaking. This information is then evaluated by the emotions as some- thing that needs attention. This evaluation is passed on to the will, where the rules of what ought to be done and under what circumstances reside. If there are no higher priority items vying for the attention of the will, then the goal may be selected. Once this occurs, the behavior generating hierarchy will be committed to decompose this goal into a sequence of actions. At each instant of time t k the sensory-processing module at each hierarchical level extracts feedback vectors F* required by the H behavior-generating modules at each level for goal decomposition. At the instant t when the goal is selected, the feedback F? at the various levels causes the selection of the initial subgoal decompositon P°. This deter- mines the initial direction of the tra- jectories T P ,. on their way toward the goal state. As the task proceeds, the recognition of subgoal completions and/or unanticipated obstacles trig- gers the selection of the proper se- quence of actions directed toward the goal achievement. The entire set of trajectories T ^describes the sequence of internal states of the brain which underlie and give rise to the observable phen- omena of purposive behavior. These are the deep structure of behavior. Only the output trajectory, the ter- minal or bottom level trajectory, is manifested as overt action. The ex- tent to which the trajectories T P] . are independent of feedback is the extent to which behavior is preprogrammed. The extent to which the feedback pulls the T P . trajectories along predic- table paths to the goal state is the ex- tent to which behavior is adaptive. For some goals, such as hunting for prey or searching for breeding ter- ritory, the selection of the goal merely triggers migratory searching behavior which continues until feed- back indicates that the goal is near at hand. For such goals, behavior is in- definite and highly feedback depen- dent. For other goals, such as building a nest, making a tool, courting a mate, or defending a territory, behavior is more inner- directed, requiring only a few sensory cues for triggers. In either case, while in the acting mode the sensory data flowing in the sensory-processing hierarchy is highly dependent on (if not directly caused by) the action itself. If the action is speech, the sensory- processing hierarchy is analysing what is spoken, and provides feed- back for control of loudness, pitch, and modulation. If the action is physical motion, data from vision, proprioception, and touch sensors are all highly action dependent, and the sensory analysis is primarily directed toward servo control of the action itself. In the action mode, the M,- associative memory modules provide context in the form of predicted data to the sensory-processing modules in order to distinguish between sensory data caused by motion of the sensors and that caused by motion of the en- vironment. What is predicted is whatever was stored on previous ex- periences when the same action was generated under similar circum- stances. This allows the sensory- processing hierarchy to anticipate the sensory input and to detect more sophisticated patterns in the sensory data than would otherwise be possi- ble. Observing — The Sensory Analysis Mode A second mode of operation of the crosscoupled hierarchy is the analysis of sensory data from external sources not primarily caused by action of the behavior-generating hierarchy. For example, when listening to a concert, a speech, or a play, there is little ac- tion going on in the muscles and motor neurons. The lower levels of behavior-generating hierarchies are quiescent, or set to a constant value, or given a command to execute an 138 September 1979 © BYTE Publications Inc More than meets the eye. The new Series 5000 is mighty for its size. In more than several thousand ways! In fact, it's the first small system offering over a megabyte of integrated mini-floppy capacity. And with its super memory management, you can have better than 300k of RAM in desk or desktop versions. But hardware is just the tail of the whale. . . It's the wide selection of software that really makes this system mighty. Operating systems? Choose CP/M* with CBASICf— the most widely accepted small com- puter operating system ever. Or MVT-FAMOSf * a multi-user, multi-tasking operating system with file management like the big guys. Or MICROCOBOL,tt also for multiple users, but implemented in COBOL, familiar to commercial users the world over. And application programs for these operating systems number in the thousands. From real estate to accounting, taxes to inventory control, they're all available at low cost — ready to run. When you add these software and hardware features to Industrial Micro Systems' reputation for rugged, reliable quality products you'll begin to see it all. A lot more system than your first glance reveals. See even more at your dealer. Call us to find out the name of your nearest dealer. He'll tell you everything you need to know. And really open your eyes 'Trademark of Digital Research Inc. "Trademark of MVT Microcomputer Systems Inc. "("Trademark of Software Systems ttProduct of CAP-CPP INDUSTRIAL MICRO SYSTEMS The great unknown. 628 N. Eckhoff St., Orange, CA 92668, '714)633-0355 Circle 169 on inquiry card. BYTE September 1979 139 Circle 352 on inquiry card. SOFTWARE BREAKTHROUGH! A true breakthrough in 8080 development software has been achieved . . . R-A-l-D RAID stands for "Real-time In- teractive Assembler Debug," but RAID is much more. SIMULATOR " RAID is a true simulator and real-lime debug in one! Simulation mode provides TOTAL CONTROL of test program. It's crash proof! Segments of memory may be write-protected, limits specified for stack, program counter, etc. Simulation mode is transparent and both modes may be used together for high speed simulations. SYMBOLIC DEBUG ■ RAID is a fully symbolic debug, including labels and operands! Also included are multi- ple radix, multiple breakpoints, memory search, 9 display for- mats, single-step, multi-step, display/alter registers or memory, programmable output, etc. Over 70 commands in all! Memory ASSEMBLY/DISASSEMBLY may be displayed or altered in instruction mnemonic form com- plete with symbolic labels and operands. Exclusive feature per- mits "following" subroutines during dis-assembly. TRAGINCa ■ Elaborate trace facilities have been includ- ed. Trace each instruction as executed, trace subroutines as entered and exited, trace by breakpoint dumps with user pro- grammable dump data. FULL DISK ACCESS ■ In addition to loading/- saving named files, RAID permits reading/writing on a specified track & sector basis. FLOATING POINT OPTION ■ Permits direct display or alteration of FPP{see below) numbers. 12 digit mantissa, exponent to ± 127, BCD format. CP/M COMPATIBLE - RAID »« run on any CP/M system of 24K or more. Works with both ASM and MAC assemblers fully symbolically. TO ORDER: Specify software desired and enclose check or money order (COD ok). A) RAID without floating point option $99.95 B)RAID with floating point option, and FPP source code $150.00 C) FPP Floating Point Processor only $99.95 D)RAID Documentation Only $15.00 E) ISIS to CPM Conversion Utilities $99.95 All software supplied on CP/M compatible 8" diskette. ISIS versions also available. SOUTHERN SYSTEMS OF BIRMINGHAM Post Office Box 3373A Birmingham, AL 35205 (205) 933-1659 overlearned task which can be carried out without any assistance from the upper levels. The sensory-processing hierar- chies, however, are very busy. They are filtering and predicting, recogniz- ing patterns and trajectories, locking on to rhythms and harmonious periodicities, and tracking targets of attention. Predictions generated by the M modules are clearly required for these types of analyses, whether or not the organism is engaged in physical activity. This suggests that the upper levels of the behavior- generating hierarchies (which are not currently required for generating behavior) might be used instead to generate hypotheses and subhypo- theses which in turn produce context and predictions to aid the sensory- processing hierarchy in the recogni- tion, analysis, and understanding of incoming sensory data. At each level hypotheses which generate T K predictions that match or track the T E sensory data trajectories will be confirmed. If the hypothesized T K trajectories are only close to the T E observations, they can be pulled by error signal feedback TV from the pro- cessing hierarchies. When a hypo- thesis is successful in generating predictions which match the sensory data stream, the loop at that level locks onto the sensory data. When lock-on is simultaneously achieved at many different levels, we can say that the processing-generating hierarchy "understands" the incoming data (ie: it can follow and predict it at many different levels). The depth of understanding depends upon how many levels lock onto the sensory data stream. The accuracy of understanding depends upon how precisely the hypotheses track and predict the incoming sensory data. It is easier to follow a trajectory than to reproduce it. When observing a procedure, the generating hierarchy merely needs to produce hypotheses which are in the right vicinity so that they can be synchronized with the sensory input. Uncertainties at branch points in T P , do not matter greatly because errors are quickly corrected by comparing T fi . with T £l .. On the other hand, reproducing a procedure requires that the H func- tions be capable of generating T Pl tra- jectories which are quite precise over their entire length. They must not wander outside of the success envelope or miss any critical branch points. Needless to say, the latter is a much more exacting computational problem, and offers an explanation for why a student may be able to follow the reasoning of his professor's lecture, but is unable to pass an exam without additional drill and practice. Attention The directing or focusing of atten- tion is essentially a purposive action whose goal is to optimize the quality of the sensory data. The basic elements of attention are orienting (positioning the body and sensory organs so as to facilitate the gathering of data) and focusing (blocking out extraneous or peripheral information so that the sensory processing system can bring all of its capacities to bear on data that is relevant to the object of attention). The orienting element is simply a behavioral task or goal to acquire and track a target. The fo- cusing element is a filtering problem which can be solved by a hypothesis or goal decomposition which evokes the appropriate masks or filter func- tions from the R, modules so as to block out all but the relevant sensory input data. Thus, attending is a combination of observing and acting. It is primarily a sensory analysis mode activity, with a stong assist from the task execution mode. Imagining — The Free- Running Mode A third distinct mode of operation occurs when the upper levels of the processing-generating hierarchy are largely disconnected from both motor output and sensory input. In this mode high-level hypotheses T P . may be generated, and predicted sensory data T fi| recalled. In the absence of sensory input from the external en- vironment, these recalled trajectories make up all of the information flow- ing in the sensory-processing hier- archy. The processing modules G, operate exclusively on the internally recalled R, trajectories producing T Q ,experiences and T Fi feedback. The ^trajectories act on the generating hierarchy so as to modify and steer the Xs, trajectories creating new hypotheses T P ,.. The system is free running, guided only by stored ex- periences M,, learned interpretations G„ and practiced skills H„ for 140 September 1979 © BYTE Publications Inc w*k ^ Oo« o n 0>*\ ■ Huntsville, AL Pho, , AZ Little Rock, AR Belmont, CA Dublin, CA El Cerrito, CA Hayw3rd, CA Lawndale, CA Los Altos, CA Los Angeles. CA Pasadena, CA Sacramento, CA Saddleback Valley, CA San Bernardino, CA San Diego, CA San Diego East, CA San Francisco, CA San Jose, CA San Rafael, CA Santa Maria, CA Santa Rosa, CA Thousand Oaks, CA Tustin, CA Jacksonville, FL Walnut Creek, CA Miami, FL Colorado Springs, CO Atlanta, GA Denver, CO North Denver, CO Fairfield, CT Hartford, CT Newark, DE Boca Raton, F L Coral Gables, FL Ft. Lauderdale, FL HonolL Arlington Heights Downers Grove, I Mundelein, IL Niles, IL Oak Lawn, IL Peoria, IL Indianapolis, IN Overland Park, KS Louisville, KY Boston, MA Rockville, MO Grand Rapids, Ml Rochester, Ml Southfield, Ml Bloomington, MN Hopkins, MN Springfield, MO St. Louis, MO Omaha, NE Nashua, NH Cherry Hill, NJ Bergen County, NJ Morristown, NJ Buffalo, NY Ithaca, NY Nassau County, NY Charlotte, NC Cleveland East, OH Cleveland West, OH YOU'RE first in three... AND SO ARE WE. We are what our friends, you the ComputerLand customer, make us. You support growth. And ComputerLand expands. There are more than 90 stores worldwide serving you. You're quality oriented. That's why your ComputerLand store has the widest selection of the finest computer systems and software anywhere. You have high professional standards. These yset the guidelines for your ComputerLand staff . . . experts who can analyze and fill needs at all levels. You settle for nothing less than complete solutions. That's what gives your store national recognition for its products and service. In short, you give direction for growth. This is what has made your store #1, in just three short years. COME TO THE PARTY Starting September 1 7 at your local ComputerLand store, there'll be an anniversary special waiting for you. And on September 22, all day, we're hosting a gigantic birthday party ... to celebrate our shared success. Bring your family, your friends. And join in the fun. It's our way of saying thanks ... for yesterday, today and tomorrow. ComputerLand 1*100 Cotalino Street, San Leonora, CA 94577 1415] 895-9363 at all participating stores. Columbus, OH Oklahoma City, OK Portland, OR Harrisburg, PA Lehigh Valley, PA Paoli, PA Austin, TX Dallas, TX SouthWest Houston, TX Houston Bay Area, TX Salt Lake City, UT Tyson's Corners, VA Bellevue, WA Federal Way, WA Tacoma, WA Madison, Wl Milwaukee, Wl INTERNATIONAL Adelaide, Australia Brisbane, Australia Melbourne, Australia Perth, Australia Sydney, NSW Australia Brussels, Belgium Burlington, Canada Calgary, Alberta Canada Toronto, Canada Winnipeg, Canada Copenhagen, Denmark Levallois, France Manila, Philippines Singapore Stockholm, Sweden Circle 75 on inquiry card. BYTE September 1979 141 generating strings of hypotheses and decomposing goals and tasks. The upper levels of the crosscoupled hierarchy are, thus, imagining (ie: generating and analyzing what would be expected if certain hypothesized goals and tasks were to be carried out). Imagination is based on stored ex- periences and driven by hypothesized actions. It is constrained in large measure by the knowledge frames, world models, expected values, and belief structures (IF I do this, THEN such and so will happen) embedded in the upper levels of the cross-coupled processing-generating hierarchy. If we attempt to hypothesize some action X which lies outside of the neighborhood of generalization of prior experience, we get no recalled R, vectors from memory M,. In this case we say "we cannot imagine what X would be like." One of the functions of the free- running mode is to remember or recall past experiences by hypothesiz- ing the same goals as when the ex- perience was recorded. Thus, in our imagination we can reach back and relive experiences, recall events, and, hence, remember facts and relation- 64KB MICROPROCESSOR MEMORIES S-100- $750.00 LSI - $750.00 CI-S100 64K x 8 CI-1103 32K x 16 TTimnittnffn!T?Tiiti' — ■ ' CI-6800 64K x 8 friii & i I •ujuu — CI-8080 64K x 8 • SBC 80/10 -$750.00 • 6800 -$750.00 CI-S100 — 64K x 8 on a single board. Plugs directly into the IMSAI, MITS, TDL, SOL and most other S-100 Bus computers. No wait states even with Z80 at 4Mhz. Addressable in 4K in- crements. Power requirement 6 watts. Price $750.00. CI-1103 — 8K words to 32K words in a single option slot. Plugs directly into LSI 11, LSI 11/2, H11 & PDP 1103. Addressable in 2K increments up to 1 28K. 8K x 1 6 $390.00. 32K x 1 6 $750.00 qty. one. CI-6800 — 16KB to 64KB on a single board. Plugs directly into Motorola's EXORcisor and compatible with the evaluation modules. Addressable in 4K increments up to 64K. 16KB $390.00. 64KB $750.00. CI-8080 — 16KB to 64KB on single board. Plugs directly into Intel's MDS 800 and SBC 80/10. Addressable in 4K increments up to 64K. 16KB $390.00. 64KB $750.00 € Tested and burned-in. Full year warranty. Chrislin Industries, Inc. Computer Products Division 31352 Via Colinas • Westlake Village, CA 91361 • 213-991-2254 ships from our past. Imagination, however, is not limited to duplication of past experiences. We can also re- arrange sections of learned trajec- tories to create experiences in our minds which never occurred. We can string together trajectories in new combinations or insert new modifier variables in various hypothesis vec- tors. We can watch a bird fly and substitute a "self" variable in place of the bird to imagine ourselves soaring through the sky. We can listen to a story of adventure and imagine ourselves in the place of one of the characters. Imagination allows us to hypothesize untried actions and, on the basis of M functions learned during previous experiences, to predict the outcome. Planning Imagination gives us the ability to think about what we are going to do before committing ourselves to ac- tion. We can try out, or hypothesize prospective behavior patterns, and predict the probable results. The emotions enable us to evaluate these predicted results as good or bad, desirable or undesirable. Imagination and emotional evalu- ators together give us the capability to conduct a search over a space of potential goal decompositions and to find the best course of action. This type of search is called planning. When we plan, we hypothesize various alternative behavior trajec- tories and attempt to select the one that takes us from our present state to the goal state by the most desirable route. Imagined scenarios which pro- duce positive emotional outputs are flagged as candidate plans. Favorably evaluated scenarios or plans can be repeatedly rehearsed, reevaluated, and refined prior to initiation of behavior-producing action. Imagined scenarios which produce negative evaluation outputs will be avoided if possible. In some situa- tions it may not be possible to find a path from our present state to a goal state, or at least not one which pro- duces a net positive evaluation. Repeated unsuccessful attempts to find a satisfactory, nonpunishing plan, particularly in situations recognized as critical to one's well- being, correspond to worry. One of the central issues in the study of planning is the search strategy, or procedure, which dictates 142 September 1979 © BYTE Publications Inc Circle 47 on inquiry card. ANOTHER FIRST FROM MOUNTAIN HARDWARE. SUPERTALKER. YOUR APPLE. SuperTalker allows you to add the dimension of human speech output in your computer programs. Add voice to games. Pro- gram verbal prompting for the operator of your busi- ness system. Use verbal warnings under program con- trol as an enunciator in com- mercial security or control rooms. Create educational programs that verbally coach the student. THE SUPERTALKER SYSTEM. SuperTalker is a new Mountain Hardware peripheral system which allows the Apple II computer to output exception- ally high quality human speech through a loud- speaker under program control. Output may also be directed through any RA. or stereo system. Initially, spoken words are digitized into RAM memory through the system microphone. Speech data in RAM may then be manipulated like any other stored data. A COMPLETE PACKAGE. The SuperTalker peripheral system consists of: The SuperTalker peripheral card which plugs into FOR YOUR APPLE n Apple H; a microphone; a loudspeaker; easy- to-use operating soft- ware and documentation; plus, two ready-to-run SuperTalker programs. OPERATING SYSTEMS. In order to achieve maximum utility using SuperTalker, the SuperTalker Disk Operating System permits output of human speech under program control with direct I/O routines. It also provides a preparation pro- gram which permits the creation of voice files on diskette. BASIC program routines are provided which require only one-line statements to out- put a word or phrase. Routines also support cassette storage. TEACH YOUR COMPUTER TO TALK. For $279 assembled and tested, SuperTalker gives your Apple II a voice in the matter. AVAILABLE NOW. Mountain Hardware's SuperTalker, Apple Clock and 100,000 Day Clock™ (for S-100 bus computers) are available through computer dealers worldwide. KJ Mountain Hardware, Inc. & LEADERSHIP IN COMPUTER PERIPHERALS 300 Harvey West Blvd., Santa Cruz, CA 95060 (408) 429-8600 Sounds super. D Send me everything I need to know about SuperTalker. D Also information on your Real-Time clocks for Apple II and S-100. Name Address. City_ . State . .Zip. Apple II is a trademark of Apple Computer, Inc. Circle 257 on inquiry card. BYTE September 1979 143 which of the many possible hypo- theses should be evaluated first. In most cases, the search space is much too large to permit an exhaustive search of all possible plans, or even any substantial fraction of them. The set of rules for deciding which hypotheses to evaluate, and in which order, are called heuristics. Heuristics are usually derived in an ad hoc way from experience, acci- dent, analogy, or guesswork. Once discovered, they may be passed from one individual to another, and from one generation to another by teaching. Historically, artificial intelligence researchers have been fascinated by the subject of heuristics. At least a portion of this interest is a result of their recursive nature. A heuristic is a procedure for finding a procedure. When this recursion is embedded in a cross-coupled processing-generating hierarchy with the rich complexity of the human brain, it becomes clear why the thoughts and plans of humans are filled with such exquisite subtleties, and curious, sometimes in- sidious reasoning. It also provides some insight into the remarkable phenomenon of self-consciousness Built-in Interface for TRS-80, PET and Apple II Computers Axiom has made it simple for TRS-80, PET and Apple II users. Just go to your computer store and pick up an Axiom printer with the appropriate built-in interface. Take it home, plug it in and start printing. We even supply the cable and connector. There are two models: The EX-801 prints upper and lower case alpha- numeric characters and all the graphic symbols used by your com- puter. The EX-8S0 goes a step further, providing precise alignment of both horizontal and vertical dot patterns for a true hardcopy of computer gen- erated graphics. With up to 128 dots per inch resolution, the only limit is your imagination. The price is right, too. Just $535 for the EX-801. So visit your computer store today. /mom 5932 San Fernando Road, Glendale, CA 91202 (213) 245-9244 • TWX: 910-497-2283 (ie: a computing structure with the capacity to observe, take note of, analyze, and, to some extent, even understand itself.) Much of the artificial intelligence research in planning and problem solving has its origins and theoretical framework based on simple board games where there are a finite (although sometimes very large) number of possible moves. The discrete character of such games, together with the digital nature of computers, led naturally to the analysis of discrete trees, graphs, and search strategies for such structures. Planning in a natural environment is much more complex than searching discrete trees and graphs. In the study of planning in the brain it is necessary to deal with the continuous time- dependent nature of real world variables and situations. States are not accurately represented as nodes in a graph or tree; they are more like points in a tensor field. Transitions between states are not lines or edges, but multidimensional trajectories (fuzzy and noisy at that). In a natural environment, the space of possible behaviors is infinite. It is clearly im- possible to exhaustively search any significant portion of it. Furthermore, the real world is much too unpredic- table and hostile, and wrong guesses are far too dangerous to make ex- ploration practical outside of a few regions in which behavior patterns have had a historical record of suc- cess. Thus behavior, and hence im- agination and planning, is confined to a relatively small range of possi- bilities, namely those behavior and thought patterns which have been discovered to be successful through historical accident or painful trial and error. Both the potential behavior patterns and the heuristics for selec- ting them are passed from one genera- tion to another by parents, educators, and civil and religious customs. Daydreaming or Fantasizing The fact that the imagination can generate hypothetical scenarios with pleasurable emotional evaluations makes it inevitable that such scenarios will, upon occasion, be rehearsed for their pleasure-pro- ducing effect alone. This is a pro- cedure that can only be described as daydreaming or fantasizing. When we daydream we allow our hypothesis generators to drift 144 September 1979 © BYTE Publications Inc Circle 13 on inquiry card. S reasons why you should not buy the electric pencil II ^* ° 1978 Michael Shrayer Check the appropriate box(es): You love typing the same copy 20 thousand times a day. □ Your secretary can type 250 words per minute. □ You're dying to spend $15,000 on a word processing system, just for the tax investment credit. □ All your capital assets are tied up in a 10-year supply of correction fluid. □ You never commit a single thought to paper. If you have checked one or more boxes, you do not need The Electric Pencil. On the other hand, you may want to join the thousands of people who haven't checked a single box. TM The Electric Pencil II is a Charac- ter Oriented Word Processing System. This means that text is entered as a string of continuous characters and is manipulated as such. This allows the user enormous freedom and ease in the movement and handling of text. Since line endings are never delineated, any number of characters, words, lines or paragraphs may be inserted or deleted anywhere in the text. The entirety of the text shifts and opens up or closes as needed in full view of the user. The typing of carriage returns or word hyphenations is not required since lines of text are formatted automatic- ally. As text is typed and the end of a line is reached, a partially completed word is shifted to the beginning of the following line. Whenever text is insert- ed or deleted, existing text is pushed down or pulled up in a wrap around fashion. Everything appears on the video display as it occurs, which elim- inates guesswork. Text may be review- ed at will by variable speed scrolling both in the forward and reverse direc- tions. By using the search or search and replace functions, any string of characters may be located and/or re- placed with any other string of charac- ters as desired. Numerous combinations of line length, page length, line spacing and page spacing permit automatic formatting of any form. Character spacing, bold face, multicolumn and bidirec- tional printing are included in the Diablo versions. Multiple columns with right and left justified margins may be printed in a single pass. Wide screen video Versions are available for Imsai VIO video users with the huge 80x24 character screen. These versions put al- most twice as many characters on the CP/M versions Digital Research's CP/M, as well as its derivatives, including IMDOS and CDOS, and Helios PTDOS versions are also available. There are several NEC Spinwriter print packages. A utility program that converts The Electric Pencil to CP/M to Pencil files, called CONVERT, is only $35. Features • CP/M, \MDOSand HELIOS compatible • Supports four disk drives • Dynamic print formatting • DIABLO and NEC printer packages • Multi-column formatting in one pass • Print value chaining • Page-at-a-time scrolling • Bidirectional multispeed scrolling con- trols • Subsystem with print value scoreboard • Automatic word and record number tally • Cassette backup for additional storage • Full margin control • End-of-page control • Non-printing text commenting • Line and paragraph indentation • Centering • Underlining • Bold face Upgrading policy Any version of The Electric Pencil Have we got a version for you? The Electric Pencil II operates with any 8080/Z80 based microcom- puter that supports a CP/M disk sys- tem and uses an Imsai VIO, Processor Tech. VDM-1, Polymorphic. VTI, Solid State Music VB-1B or Vector Graphic video interface. REX versions also available. Specify when using CP/M that has been modified for Micropolis or North Star disk systems as follows: for North star add suffix A to version number; for Micropolis add suffix B, e.g.,SS-IIA, DV-IIB. Vers. Video Printer Price SS-II SOL TTY or similar $225 SP-ll VTI TTY or similar 225 SV-II VDM TTY or similar 225 SR-II REX TTY or similar 250 Sl-ll VIO TTY or similar 250 DS-II SOL Diablo 1610/20 275 DP-II VTI Diablo 1610/20 275 DV-II VDM Diablo 1610/20 275 DR-II REX Diablo 1610/20 300 Dl-ll VIO Diablo 1610/20 300 NS-II SOL NEC Spinwriter 275 NP--II VTI NEC Spinwriter 275 NV-II VDM NEC Spinwriter 275 NR-II REX NEC Spinwriter 300 Nl II VIO NEC Spinwriter 300 SSH SOL Helios/TTY 250 DSH SOL Helios/Diablo 300 MICHAEL SHRAYER SOFTWARE, INC 1253 Vista Superba Drive Glendale, CA. 91205 (213)956-1593 may be upgraded at any time by sim- ply returning the original disk or cas- sette and the price difference between versions, plus $15 to Michael Shrayer Software. Only the originally purchas- ed cassette or diskette will be accepted for upgrading under this policy. Attention: TRS-80 Users! The Electric Pencil has been de- signed to work with both Level I (16K system) and Level II mod- els of the TRS-80, and with vir- tually any printer you choose. Two versions, one for use with cassette, and one for use with disk, are available on cassette. The TRS-80 disk version is easily tran- sferred to disk and is fully interactive with the READ, WRITE, DIR, and KILL routines of TRSDOS 2.1. Version Stora ge Price TRC Cassette $100. TRD Disk $150. ill! Demand a demo from your dealer ! Circle 319 on inquiry card. BYTE September 1979 145 Circle 77 on inquiry card. PET PRINTER ADAPTER GET HARD COPY FROM YOUR COMMODORE PET USING A STANDARD RS-232 PRINTER iinnn "»»> nnnn ^™ 1200B 1200C The CmC ADA 1200 drives an RS-232 printer from the PET IEEE-488 bus. Now, the PET owner can obtain hard copy listings and can type letters, manuscripts, mailing labels, tables of data, pictures, in- voices, graphs, checks, needle- point patterns, etc., using a standard RS-232 printer or terminal. $98.50 ADA1200B Assembled and tested $169.00 With case, power supply and RS-232 connector ADA1200C ^dp^l^ r/j'/f Order direct or contact your local computer store. Add $3.00 for postage and handling per order. O CONNECTICUT microCOMPUTER (jjfl) =a 150 POCONO RD. BROOKFIELD. CT 06804 La (203I 775 9659 TLX: 7104560052 wherever our emotional evaluators pull them. Our imagination gravi- tates toward those trajectories which are emotionally most rewarding. Some of the most pleasurable scenarios we can imagine are physically impossible, impractical, or socially taboo. Most of us recognize these as fantasies and never attempt to carry them out. However, once a person adopts the intent to carry out a fantasy, it ceases to be a dream and becomes a plan. Thus, planning and daydreaming are closely related activities, differing principally in that planning has a serious purpose and involves an in- tent to execute what is finally selected as the most desirable of the alter- native hypotheses. This model suggests that dreaming while sleeping is similar in many respects to daydreaming. The prin- cipal difference in night dreaming seems to be that the trajectories evoked are more spasmodic and ran- dom, and are not always under the complete control of the emotions and will. Creativity The notion of planning or dis- covering procedures for achieving goals leads inevitably to the issue of creativity. If we assume that most of the H, G, and M functions in the processing-generating hierarchy are learned, then where is the creativity? Is creativity merely an illusion generated by the recursion of pro- cedures for discovering procedures? Certainly we as humans like to think of ourselves as creative. But what are we doing when we create something new? Typically we borrow an idea from here, put it together with another from there, and give it a different name. We take a familiar behavioral trajectory, add a tiny variation, and claim that we have discovered something completely new — a new dance step, dress style, song, or idea. Seldom, however, are any of these more than the slightest deviation from a preexisting pro- cedure or behavioral trajectory. To quote Ecclesiastes: "There is nothing new under the sun." True creativity, in the sense of the invention of an entirely new behav- ioral trajectory, is extremely rare, if it ever occurs at all. Furthermore, it is highly doubtful that a truly creative act would be recognized if it ever did occur. Our processing-generating hierarchies cannot lock on to sensory input patterns which are totally dif- ferent from everything that is stored in them. We reject such inputs as meaningless noise, or as alien and possibly hostile. True creativity would be as incomprehensible as a book written in a foreign language, or a theorem expressed in an unknown mathematical notation. In one sense we are all creative in everything that we do, since no two behavioral trajectories are ever repeated exactly. However, the day- to-day variations in our ordinary behavior are not what we usually mean when we speak of creativity. We take pride in those moments of in- spiration when something clicks, and we produce a great invention or a work of art. Nonetheless, if we analyze a list of the great creative ideas which have AIM 65 AIM 65 is fully assembled, tested and warranted. With the addition of a low cost, readily available power supply, it's ready to start working for you. It has an addressing capability up to 65K bytes, and comes with a user-dedicated 1K or 4K RAM. • Thermal Printer • Full-Size Alphanumeric Keyboard • True Alphanumeric Display • Proven R6500 Microcomputer System Devices • Built-in Expansion Capability • TTY and Audio Cassette Interfaces • ROM Resident Advanced Interactive Monitor • Advanced Interactive Monitor Commands PRICE: $375. 00(1 k ram) Plus $4.00 UPS (shipped in U.S. must give street address), $10 parcel post to APO's, FPO's, Alaska, Hawaii, Canada, $25 air mail to all other countries We manufacture a complete line of high quality expansion boards. Use reader service card to be added to our mailing list, or U.S. residents send $1.00 (International send $3.00 U.S.) for airmail delivery of our complete catalog. ^ ^ ENTERPRISES INCORPORATED 2967 W. Fairmount Avenue • Phoenix, AZ 85017 • (602) 265-7564 146 September 1979 © BYTE Publications Inc Circle 324 on inquiry card. Circle 224 on inquiry card. yjiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiniiiiiiiiiiiiiii iiiiiiiiiiiiiiiii iiiiiiiiiiiiiiitiiiiiiuii iiiitiiiiiiitiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiitiiiitiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiini^ I MICROCOMPUTER SOFTWARE I [Floppy and hard disk systems] Medical Systems for Doctors Word Processing for Attorneys Membership for Churches Inventory for Auto Dealers Client Accounting for CPA's Listings for Realtors Fund Raising for Agencies Financial Systems for all Companies I If yau are planning or developing business and accounting applications in the above areas for sale in the national marketplace, our com- 2 peny will review and evaluate your software to determine its suitability to the small business environment. We will arrange marketing ; channels for your firm, and estsblish acceptable royalty provisions for all of your products sold to our customers. If interested in further 5 information about our National Microcomputer Software Marketing Plan, send a list of your applications with sample report and screen : layouts, and hardware specifications to: b SOFTWARE REVIEW STAFF = L MICROTEL, INC. S_ P.O. BOX 10SB GASTONIA, NORTH CAROLINA S8052 704-866-7157 =71 iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiifiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiijiiiiiiiiiiifiiiiiiiiiiiiiiiitifiiiiiiiiiiiiifiaiiiiiiiiiiitiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiitiiiiiiiiiiiiii fT^ shaped human history, we find that even these have been little more than clever rearrangements of well-known preexisting patterns or procedures. Consider the fact that it took the human race many millenia to learn to start a fire, to grow a crop, to build a wheel, to write a story, to ride a horse. Even the Greeks did not know how to build an arch. Yet these are all simple procedures which any child can understand and more or less master. Surely our ancestors as adults were as intelligent and creative as to- day's children. Why did they fail for hundreds of years to discover these simple yet highly useful procedures? It was because they had no one to teach them. A modern child knows about wheels because he is taught. He plays with toys that have wheels. He rides in vehicles with wheels. If a modern child grew up in a culture where he never saw a wheel, he would never think of one, nor would his children, or his grandchildren, any more than his ancestors did for thousands of years before him. The reason that we value creativity so highly is because it is so rare and so highly advantageous. Once a new and useful procedure like navigating a ship, making steel, or flying an airplane is discovered, it can easily be taught to others. Entirely new worlds of possible behavior patterns open up for all who possess the secret. We learn to solve problems, to in- vent, and to be creative, in much the same way as we learn any other goal- directed behavior pattern such as hunting, dancing, speaking, or behaving in a manner that is accep- table to and approved by our peers. We learn it from a teacher. The beauty, the sense of awe and wonder we experience when confronted by a work of creative genius, derives not so much from its novelty /creativity as from the skill and precision with which it is executed. Implications for Robot Design There is little need to worry about programming "creativity" into our machines. If we design systems with sufficient skill in executing tasks and seeking goals, and sufficient sophis- tication in sensory analysis and con- text sensitive recall, and if we teach these systems procedures for selecting behavior patterns which are appro- priate to the situation, then they will appear to be both intelligent and creative. But there will never be any particular part of such a device to which one can point and say "Here is the intelligence," or "Here is the creativity." Skills and knowledge will be distributed as functional operators throughout the entire hierarchy. To the degree that we are successful, in- telligence and creativity will be evidenced in the procedures which are generated by such systems. Above all, we should not expect our robots to be more clever than ourselves, at least not for many decades. In particular we should not expect our machines to program themselves, or to discover for themselves how to do what we do not know how to teach them. We teach our children for years. It will take at least as much effort to teach our machines. We must show our robots what c, PET ANALOG INPUT Analog to Digital Conversion System for the Commodore PET Computer Give the PET the ability to sense* iheasuref and control the world around it with n*V1 SYSTEMS modules. Just plus Ihe PETSET1 into the PET to 3et 16 channels of analog input. Screw terminals are provided for each channel so you can hook up Joysticks^ Pot.s» or wha lever appr opt i a te sen sor s you have . Each of the 16 analod inputs* in the ranse of to 5.12 volts* is converted to a decimal number between and 255 < 20 mil livol ts per count ) . Conversion time is 100 m i cr oscon ds . In addition * Lhe PETMOD provides two IEEE ports and one user port as well as a LW1 SYSTEMS port. Software is provided. A one line program is all th3t is necessary to read a channel . ^ — f f»\ O unnui r PET INTERFACE Kiy interface no "^] 1RS-80 t TRS-IO INTERFACE ACCELERATION LEVEL • p*lluo level • ETC... 1 -AIM161 1 - PETMOD 1- CABLE A24 1 - MANM0D1 1 - POW 1 KETSET1 16 ANALOG INPUTS -8 BITS -100 MICROSEC 24 INCH INTEBXONNECT CABLE P0WEH MODULE ] [ VISA A00 PETSETIa for 110 VAC $295 PETSET1* for 230 VAC $305 Ordtr dir.ci or conlacl your loeil compultr itort. CONNECTICUT microCOMPUTER, Inc. 150 POCONO ROAD BROOKFIELD, CONNECTICUT 06804 TEL: (203) 775-9659 TWX: 710-456-0052 AND M/C ACCEPTED - SEND ACCOUNT NUMBER, EXPIRATION DATE AND SI0N ORDER. $3 PER ORDER FOR SHIPPING a HANDLING - FOREIGN ORDERS ADD 10% FOR AIR POSTAOE. Circle 78 on inquiry card. September 1979 © BYTE Publications Inc 147 Circle 73 on inquiry card. -f?A^ M Pascal MICROENGINE™ 16-bit P-code CPU Pascal executes 13x faster than on an LSI-11 and 3x faster than on a PDP11-34! $ 2695* £m\J%J\J READY TO RUN s 2995 List price s 1 795* Without case & power supply STANDARD • 16-bit P-code CPU • 64K bytes RAM • Floppy disk controller • Direct memory access controller • Floating point hardware • 2 serial (RS-232) I/O ports— 50 to 19200 baud • 2 parallel I/O ports • Pascal & Basic compilers, text editors, file manager, CPU & memory diagnostics, symbolic Pascal debugger, linker, utilities, etc. The MICROENGINE'" P-Machlne architecture implements direct execution of P-code (UCSD Pascal version 3.0) replacing software inter- preters. All data and I/O paths are 16 bits wide. Both single and multi-byte instructions are available. Floating point hardware using the proposed IEEE standard supports the execution of floating point instructions. P-Machine architecture optimizes memory utilization. Stack design renders Pascal programs automatically reentrant and recursive with no performance penalty. Extensive compiler error checking and high level language sustains high reliability. Programs are transportable to other systems running Pascal. Built-in floppy disk controller handles up to 4 drives, switch selectable for 5% or 8 inch, single or double sided. A hard disk controller will be available soon. $ 799' List price s 956 PERKIN-ELMER (Model 550) Shugart floppy disk (Model SA850) '695' Shugart floppy disk (Model SA800) '595' Texas Instruments printer (Model 810) l 1895" X-pert Systems'" designed by Computex are integrated and cost effective. Complete 16-bit systems are available starting as lowas s 3139. Customer satisfaction is guaranteed. Full refund with the return of any product within 10 days. Service contracts available. Systems catalog $1 MICROENGINE™ owners manual '19.95 postpaid. "LIMITED TIME cash price. 10% down guarantees priority. IL residents add 5% sales tax. Master Charge and VISA cards accepted. (312)684-3183 COMPUTER "THE COMPUTER EXPERTS" 5710 Drexel, Chicago, IL 60637 each task is and how to do it. We must lead them through in explicit detail, and teach them the correct response for almost every situation. This is how industrial robots are pro- grammed today at the very lowest, levels, and this is, for the most part, how children are taught in school. It is the way that most of us learned everything we know, and there is no reason to suspect that robots will be programmed very differently. Surely it is as unreasonable to expect a robot to program itself as it is to expect a child to educate himself. We should not expect our robots to discover new solutions to unsolved problems or to do anything that we, in all the thousands of generations we have been on this earth, have not learned how to do ourselves. This does not mean that once we have trained our robots to a certain level of competence that they can't learn many things on their own. We can certainly write programs to take the routine and the tedium out of teaching robots. Many different laboratories are developing high-level robot programming languages. We already know something about how to represent knowledge in computers about mathematics, physics, chem- istry, geology, and even medical diagnosis. We know how to program complex control systems and to model complicated processes, and we are rapidly learning how to do it better, more quickly, and more reliably. Soon perhaps it will even be possible to translate knowledge from natural language into robot language so that we will be able to teach our robots from text books or tape recordings more quickly and easily than humans. We can even imagine robots learning by browsing through libraries or reading scientific papers. But it is a mistake to attempt to build creative robots. We are not even sure what a creative human is, and we certainly have no idea what makes a person creative, aside from contact with other creative humans — or time alone to think. Is it both? Or neither? I believe that we should first learn how to build skilled robots — skilled in manipulation, in coping with an uncertain or even hostile environ- ment, in hunting and escaping, in making and using tools, in encoding behavior and knowledge into lang- uage, in understanding music and speech, in imaging, and in planning. Once we have accomplished these ob- jectives, then perhaps we will under- stand how to convert such skills into creativity. Or perhaps we will understand that robots with such skills already possess the creativity and the wisdom which springs naturally from the knowledge of the skills themselves. ■ Additional Reading 1. Guyton, Arthur C, Structure and Function of the Nervous System, S B Saunders, Philadelphia, 1976. 2. Piaget, J, and Inhelder, B, The Child's Conception of Space, Norton, New York 1967. 3. Sagan, Carl, The Dragons of Eden: Speculation on the Evolution of Human In- telligence, Random House, New York, 1977. 4. Schank, Roger C, and Colby, Kenneth M (editors), Computer Models of Thought and Language, W H Freeman, San Fran- cisco, 1973. Improve \burLot Take . stock in^merica. liVn A public service ol this publication GxjkI and ' n(! Advertising Council. 148 September 1979 © BYTE Publications Inc 5 STAR EDITION for users of Radio Shack's TRS-80* ***** 5-8 1 Alt cuiiiun for users of Radio Shack's TRS-80 * TRS-80 TRANSFORMED WITH PROFESSIONAL SOFTWARE PACKAGES / Manual Alone AND MUCH MORE CP/M-operating system modified lor use with TRS-80 computer and disks. In addition to the standard CP'M utilities of Editor. Assembler. Debugger etc.. we have added: DCV2 {Util- ity to convert system tapes to CP ZT*J UUI 1 1 |-H CIC , 16K pET wj , h Fu|| Sized Keyooard . interface lA/lth *£Of f %Af ffl i*P "Tape Drive Unit • Super Word Processing Software • Anderson Jac< » Interface • Super Word P obson 841 Selectric Pri le Super Word Processing System is written in 6502 isembly Language! It allows anyone to use the PET computer r such tasks as typing letters, reports, and manuscripts, tor oducing mailing lists, and for filling out forms. The software written to support any inexpensive printer and even high irformance printers with incremental and proportional letter acing. The Super Word Processor easM" ,1 ' OI,,DO oHi,e arranges, and formats text. It can mere ' ...>.-. — inds, the system .ia= ■uiuuuuiu i Ihe 2d f BUSINESS SOFTWARE FOR PET BUSINESS SYSTEM • Super Word Processing Package (Disk $99.95, Tape $24.95) • Real Estate • Statistics • Banking & Finance • Mail List Management • Data Base System • Payroll w/cost acct'g. • Small Business Package (A/R. A/P, G/L) • General Ledger • Super Random Access • Cash Receipts & Disbursements • Inventory Control (for manufacturers) Min Credit Card Order $75 VISA? N.Y. residents add 8% sales tax • Same day shipment on prepaid and credit card orders • Add S5 shipping for computers. S3 for boards. $1 each cassette tape. Open Mon-Fri 10-6 Sat 10-4 anywhere on the page. Up and down screen scrolling makes editing a breeze! Commands include end-to-end cursor line SCAN. INDENT, TAB, soft HYPHEN) for splitting syllables at the end of a line.f and four-direction cursor control. Output formatting includes dynamic print control, indentation, right justification, line width and line-to-line spacing and proportional letterspacing. Also included are programming capabilities for performing "*""lful tasks 08 direct-mall form-letter typing, multiple Minting, and automatic multiple forms entry. You may obtain this system in a cassette or disk drive version. PERIPHERALS FOR PET • 24K Memory Expansion • 16K Memory Expansion • PET to RS232 Serial • 2 Way Serial/Communication • Modem Board for PET • Analog to Digital Board for 16 Devices • Second Cassette Drive ■ Parallel Printer Interface PET MUSIC BOX from SOUNDWARE Add music and sound effects to your programs. Compose. play, and hear music on your PET. Completely self-contained Free programs NEW! iron, Eventide AUDIO SPECTRUM ANALYZER • Mounts inside the PET • Third-Octave audio speciive analysts • Complete with software and documentation • Replaces equipment costing thousands of dollars $29.95 MARK SENSE CARD READER $750 ■ • Automatic turn-on and card feed| • Ideal for marking test scores • Accepts any length card • Perfect for schools & business A TO ORDER CALL TOLL FREE 800-223-7318 The COMPUTER FACTORY ■-■_ wvv-HiW-i *t IV (46th SI.) 485 Lexington Avenue 750 Third Avenue New York. N.Y. 10017 (212)687-5001 (212) PET-2001 Foreign order desk - Telex 640055 BYTE September 1979 155 ®M Software Tools Have you thought about text editing ? Our ED-80 Text Editor offers a refreshing new approach for the creation and editing of program and data files conversationally - and it saves money! Its powerful editing capabilities will satisfy the most demanding professional - yet it can still be easily used by the inexper- ienced beginner. Look at these outstanding features: ■ By far the best text editor available for microcomputer- based systems. ■ Repays its initial cost many times over with its unique time-saving editing capabilities. ■ FULL SCREEN window displays for viewing and edit- ing data a page-at-a-time, rather than line-by-line. ■ Forward and backward scrolling in the FULL SCREEN mode. ■ Displays the results of every edit command. ■ Commands include forward or backward Locate and Change, Insert, Delete, Replace, Inline, Input, Print, List, Window, Get, Put, Macro, Tabset, Append, Case, Scale, and Dump. ■ Simple line-oriented commands with character string manipulation capabilities. ■ Text may be located by string value, by line number, or by relative line number. ■ Global string search and replace capabilities. ■ Commands for moving, copying, and merging edit files on the same or different diskettes. ■ Self-explanatory diagnostic messages. ■ Single keystrokes for the most commonly used com- ands. ■ Safeguards to prevent catastrophic user errors that result in loss of the edit file. ■ Designed for today's high speed CRT's, video monitors, and teletypewriter terminals. ■ Thoroughly field tested and documented with a User's Manual of over 60 pages. ■ Compatible with existing CP/M edit files and deriva- tive operating systems. And remember - in today's interactive programming environment - the programmer's most important software development tool is the text editor. Our ED-80 Text Editor is working in industry, government, univer- sities, and in personal computing to significantly cut program develop- ment time and high labor costs. Why not let ED-80 begin solving your text editing problems today? i Id in I Mail to: SOFTWARE DEVELOPMENT & TRAINING, INC. P. 0. Box 4511, Huntsville, AL 35802 ED-80 is protected by copyright and furnished under a paid-up license for use on a single computer system. Please send additional information. Send Diskette, User's Manual, and paid-up license agreement $99.00 Specify SINGLE DENSITY Diskette size □ 5" □ 8" Send User's Manual (credited on purchase of a paid-up license) $10.00 Check or money order enclosed for J Please charge to my credit card □ VISA □ MasterCharge Card No Bank No Exp.Date | NAME. ADDRESS . CITY STATE. .ZIP_ SIGNATURE . C-l SOFTWARE DEVELOPMENT & TRAINING, INC. Post Office Box 4511 Huntsville, Alabama 35802 Dealer Inauines Welcomed ® CP/M is a trademark of Digital Research TRS-80 Microcomputer Technical Reference Handbook Published by Tandy Corporation 1979 8.5 by 11 inches, 108 pages Radio Shack catalog number 26-2103 $9.95 Since the introduction of the Radio Shack TRS-80, many hardware-minded hobbyists have wondered what makes the TRS-80 tick. Until recently most of the details have been miss- ing, and the little that was known was uncovered here and there by various users. But now Radio Shack has enlightened us all with the publication of The TRS-80 Microcomputer Technical Reference Handbook. The major contents are: System Block Diagram Description The Memory Map Theory of Operation Adjustments and Troubleshooting The Outside World Parts List Schematics The preface explains that the book is not intended to give an education in digital logic, but to teach the hard- ware enthusiast the specifics of the TRS-80. If you don't know a NOR from a NAND, this manual will not make much sense. The preface also warns that, should the owner decide to open the unit, the warranty is immediately void. The block diagram ap- pears on a double fold-out page. The diagram section also contains brief descrip- tions of the various parts of the system. There is 1 small error on the block diagram. It does not show the lower- half of the address bus going to the cassette I/O (in- put/output) port which must be addressed to operate. A memory map for any computer system reveals lots of information. The memory map in this book shows hexadecimal addresses 0000 thru FFFF, and indicates where the read-only memory, programmable memory, keyboard, and video display fall within the addressable space of the Z80 processor. The memory map shown is for a Level I machine; it is necessary to figure out what the address usage would be for a Level II machine. The real substance of the book is the 'Theory of Operation" section. Each separate section of the TRS-80 is explained in detail. This section of the book is the largest, and the video-display logic subsec- tion is the largest within theory of operation. The TRS-80 uses some unusual design techniques and a few uncommon parts. An example of this is the memory-mapped keyboard. The theory behind these design techniques and unusual parts is explained clearly, so that a person who has never seen these things can readily under- stand them. Throughout the theory of operation section, many explanations are of the type: "gate X goes low causing gate Y to go high". This causes the reader to refer constantly to the schematics at the back of the book, necessitating a lot of irri- tating page turning which could have been avoided if that portion of the schematic had been reproduced on the page with the description. Scattered throughout this section are many timing diagrams which, when used with the schematics, make the circuit descriptions easier to understand. The "Adjustments and Troubleshooting" section is also filled with infor- mation. Included are power supply checks and adjust- ments; section isolation using a flowchart; processor problem isolation using a flowchart; and troubleshooting for the keyboard, video-display logic, cassette interface, and power supply. These troubleshooting sections contain hints, and suggest possible bad parts causing 156 September 1979 © BYTE Publications Inc Circle 190 on inquiry card.. We're about to make a new name for ourselves Not that the old one was so bad. As Ithaca Audio, we've made quite a name for ourselves. As the source for CPU, memory, video display and disk controller boards to upgrade other makers' mainframes and peripherals. The company that makes those neat little RAM expansion kits. And the folks behind the world's only Z-80 Pascal compiler. But as much as we've enjoyed im- proving other people's equipment, we've been quietly moving towards larger en- deavors, with a lot of encouragement from our customers. Listening to people's prob- lems, as well as their needs. And, as a prime mover behind the IEEE S-100 Bus Standard, answering some really knotty questions. One of the results is our new identity. And our first new product : the Inter- systems DPS-1. An IEEE S-100 compatible mainframe with features that live up to its looks. Dependable operation to 4 MHz. Twenty-card capacity. A modular power supply. And something no one else has— built-in breakpoints to give you a faster, more powerful tool for testing software as well as hardware. Directly accessible from an easy-to-use front panel that's as reliable as it is functional. In short, an intelligently- designed computer for the intelligent user. There's a lot more to Intersystems. In hardware. And software. All available through the nationwide dealer network we're now assembling. You can watch this magazine for updates. Or contact us directly for straight, friendly answers and detailed information from key staff people. Just the way you always have. Because even though we're making a new name for ourselves, we'll never forget who made it possible. Ithaca Intersystems Inc. 1650 Hanshaw Road/R O. Box 91 Ithaca, NY 14850/607-257-0190 rr" ' " © 1979 Ithaca Intersystems Incorporated various problems. The subsection on video ailments contains a handy table that shows the frequency of the signals to be found at 17 dif- ferent logic gates in the video divider chain. There is also a small program and instructions for adjusting the horizontal and vertical centering. The power supply subsection has a table that shows the voltages on all the pins of the 2 723C voltage regulators. Perhaps the most inter- esting section in the book is the one entitled "The Out- side World". Here the hard- ware enthusiast can learn how to hook up an automatic back scratcher or cigarette lighter to the TRS-80. Two techniques of external circuit interfacing are presented: memory- mapped addressing and I/O port addressing. The authors were kind enough to include schematics for a coffeepot control using both techni- ques. While these particular examples may not interest everyone, they do serve to illustrate how easy it is to make your computer do things other than run pro- grams. Also included is a BASIC program to turn on the coffeepot. The last part of this sec- tion has a chart showing the signals present on each pin of the expansion connector and an explanation of the function of each pin. Armed with the information in this section, the hardware designer should be able to interface just about anything to the TRS-80. The "Parts List" section is just that! It contains many individual lists headed by the part type, such as resistors, capacitors, inte- grated circuits, etc. A part number is also given for each part. However, there is no correlation between these part numbers and Radio Shack catalog part numbers. For example, the technical manual number for a 74LS74 flip-flop is 3102015, while the Radio Shack catalog number is 276-1919. Fortunately, with integrated circuits, a part number is not really needed as long as the part is marked with its standard 7400 series number. As for most of the other parts, it is possible to substitute for the part just by reading the part descrip- tion. The "Schematics" section contains information on dif- ferences in the read-only memory parts of Level I machines, as well as 3 figures showing schematic diagrams. One diagram displays the logic on the small printed circuit that contains the read-only memory devices in Level II equipped TRS-80s. This board is attached by adhesive tape to the main printed circuit board. A rib- bon cable extends from it to the socket intended for the Level I read-only memory. The other 2 figures show different sections of the logic contained on the main printed circuit board and the keyboard printed circuit board. These figures appear on long, fold-out pages. The first page contains the Z80 processor, 3-state buffers, memory, address decoding, and keyboard. The second page shows the electronic logic for the system clock, video display, cassette I/O, and power supply. Spare gates are shown on both sheets. The schematics are well drawn, clear, and easy to read. They become rather awkward, however, when stretched out on a workbench that is probably already inhabited by the opened TRS-80 and the associated test equipment. I would have preferred the schematics split into at least 4 pages. The book is written in a clear, easygoing style. [However, the authors often use engineering jargon where it would have been simpler to use plain English . . . RSS] The authors are not identified. Scattered here and there in the manual are many valuable trouble- shooting tips of a general nature. (An example is the paragraph on checking open collector outputs.) All of the figures in the book are large and easy to read. Except for the previously mentioned criticism of the main schematic, I consider this a plus. Conspicuous in its absence is a discussion of the video monitor. No schematic is given, nor is its operation discussed. I consider this to be the only major fault with the manual, one that surely will be corrected with the next revision. Also absent is a schematic of the power supply. As mentioned earlier, the intent of this book is not to give an education in digital logic. It does not even attempt to impart knowledge about the inner workings of the Z80 pro- cessor. That is beyond the scope of the manual. Nor does it explain what is con- tained in read-only memory. Software is men- tioned only in passing. What the book does teach is how all the various devices work together to form the TRS-80. Despite its faults, I consider this manual a valuable addition to the library of any hardware- oriented TRS-80 owner. ■ Ken Fordham 7612 La Mesita Ct Tampa FL 33615 A VIEW OF THE CLASSICS The first Micro Works PSB-08 PROM Board was assembled and burned in over two years ago— eons in the micro world. Designed as an efficient, cost-effective EPROM storage system for the SWTPC 6800, its flexibility accomodates all the new S-50 computers on the market— SWTPC 6809, GIMIX, MSI and Smoke Signal Broadcasting. The 2708 EPROM remains an inexpensive, capable media for storage of subroutines, I/O handlers, monitors and even BASIC interpreters while the cost and availability of 2716s still don't justify their purchase. PSB-08 has space for up to 8 2708 EPROMS and the following exclusive features: * 1K "scratch pad" RAM— more than enough temporary storage capacity for any program requiring up to 8K of PROM * Dip-switch addressable PROM and RAM, to start on any 8K boundary in memory * I/O select capability lets you move the I/O locations to any unused 1K block in EPROM memory space, permitting memory expansion to a full 56K contiguous user RAM Originally intended for use with 6800-based system software, the PSB-08 will continue to be a valuable tool for years to come with And the relocatable I/O feature lets you keep your 6800 system up-to-date. your 6809 THE mO©D^§> The past two years have seen many microcomputer products come and go. In our history, there have been no takers on the PSB-08's warranty. Like the classics, our PROM board endures. Price: $1 19.95; regulated + 12v.: $124.95 P.O. BOX 11 1D, DEL MAR, CA 32014 71 4-756-26B7 158 September 1979 © BYTE Publications Inc Circle 231 on inquiry card. nnssp 13 INCH COLOR VIDEO MONITOR PROUDLY ANNOUNCES THE REVOLUTIONARY Tl 99/4 PERSONAL/EDUCATIONAL COMPUTER! Superior color, music, sound and graphics — and TI's powerful extended BASIC — all built in. Plus a unique, revolutionary Solid State Speech Synthesizer and Texas Instrument's special Solid State Command Module Software. OPTIONAL SOLID STATE SPEECH SYNTHESIZER s 1 49.95 SOLID STATE SOFTWARE COMMAND MODULE 99/4 COMPUTER MAIN CONSOLE UNIT There's a computer in your future. And the future is now. We've entered a new ami exeitmtrera- the ajje of t to- home computer. MRyb^vouYi' alrtrndy^uHe kmiwl- edjteable about computers and are looking for the most programming power and versatility for your money. Maybe you've just read about it, and want u> loam more. BUher way. you need to look closely at Texas Instruments TI-9W4 Home Computer. TheTI-O&tf was designed to be the first true home computer - skilled computer users and beRinners alike will Ik- aide ti. put it to effective use right away. If you know computers, you'll quickly see the difference in the Tl-99/4. Texas Instruments has taken those features you've been wanting- plus sour- von may not have heard about yet-and included them in one incredible, affordable computer system. TheTI-Dil/4 Rives you an unmatched combination of features ami caps* bilities, including: • Powerful TI-HAHK' - Built-in l.'1-digit, lloaiing point BASIC Fully compatible with ANSI Minimal BASIC, but with special features anil extensions for color, sound and graphics. ■ t'pln 72K total mi'mnri capacity- tflK RAM (Ran- dom Access Memory). 2<>K ROM (Read Only Memory) plus up to :! ° |- SW2 +5V IC3 7407 14 ^7 VCC GND Al Q A2 Bl IC2 74122 B2 Q CLR *.. R3 I0K IC3 7407 $»■ + 5V IC3 7407 ■>« IC3 7407 ^ IC3 7407 l|>! .001 — )h .01 h!i- 10.0 f + 5V V SW5 PULSE f ^h VAK-1 MOTHERBOARD • Designed specifically for use with the AIM-65, SYM-1, and KIM-1 microcomputers • Standard KIM-4* Bus • Fully buffered Address and Data Bus • Provides 8 expansion board slots • Complete with rigid card-cage • All IC's are socketed • Provides separate jacks for one audio-cassette, TTY, and Power • Completely assembled (except for card-cage) We manufacture a complete line of high quality expansion boards. Use reader service card to be added to our mailing list, or U.S. residents send $1.00 (International send $3.00 U.S.) for airmail delivery of our complete catalog. PRICE: $129.00 We also carry the SYM-1 Microcomputer with manuals $269.00 ijm\jB>- 'Product of MOS Technology ENTERPRISES INCORPORATED 2967 W. Fairmount Avenue • Phoenix, AZ 85017 • (602) 265-7564 160 September 1979 © BYTE Publications Inc Circle 325 on inquiry card. Most of us at one time or another have had the need for a TTL (transistor-transistor logic) pulser source for troubleshooting or circuit design. Since most of us are not af- fluent enough to afford sophisticated test equipment we will usually kludge a TTL oscillator or pulser when the need arises. However, the next time we need our handy little circuit we end up searching our goody box only to find that we have used the parts in another piece of equipment. What I have tried to put together is an inexpensive oscillator that hopefully will stay in 1 piece and be ready when needed. In an effort to keep it simple and inexpensive I have left out some of the niceties that are found in your more expensive com- mercial test gear: variable pulse level, variable offset, rise and fall time con- trol, double pulses, etc. Design Three integrated circuits form the basis of the oscillator: a 555 timer connected as an oscillator, a retrig- gerable oneshot and a hex driver. Potentiometers Rl and R2 in conjunc- tion with the capacitor selected by switch SWl determine the operating frequency of the 555. I used poten- tiometers for both resistances so that I could have control of the duty cycle. The equation for the operating fre- quency is given by: f= 1.44 (R1 + 2(R2))C The output of the 555 is connected to a 74122 retriggerable oneshot. The use of the oneshot allows independent control of frequency with the 555 and independent control of pulse width with the 74122. The combination of the 2 integrated circuits lets you trig- ger your oscilloscope from one edge and the other edge triggers the 74122. The 7407 was included for drive capability. SW3 allows for single pulse operation and SW4 and SW5 provide positive and negative sync and pulse outputs respectively. Construction The 3 integrated circuits were mounted on Micro Vectorbord using wire wrap sockets. The pull up resistors were mounted on the same board with wire wrap pins. The re- maining components were mounted on the front panel. I decided not to in- clude a power supply in this design because the pulser is always being used with a breadboard which has its own supply or it is being used on my processor. By using the supply of whatever I am working on I don't have to run extra ground leads. Variations If you anticipate doing a lot of work where you must be synchro- nized to an external signal, then SW6 could be replaced with a single-pole triple throw switch with the third position being the output of a 7413 Schmitt trigger. The input of the Schmitt trigger would be your exter- nal signal. Utilization There are 2 things to be careful about in the use of the Handy Pulser. One, there are certain combinations of operating frequency and pulse width that will give you a constant 1 or output; two, make sure the delay between your oscilloscope sync and pulse output keeps you on the screen. Otherwise, you can be delayed right off the screen. Specifications With the values shown in figure 1 the unit's specifications are: • Pulse repetition frequency .05 Hz thru 400 kHz • Pulse delay 2 /is thru 3 seconds • Pulse width 2 (is thru 5 seconds Final Comments As I mentioned before, I decided not to include a power supply in this design but rather use the supply of whatever I am working on. One pro- blem that arises is that most manufac- turers do not provide convenient places to pick up the +5 V and ground. Rather than install separate connectors on each card, I installed a 5 V regulator with convenient con- nectors on the mainframe of my com- puter. This has proven to be a great asset. If nothing else, it is a handy place to find ground since the frame is not ground. I used an LM-309 regulator with pin jacks and ter- minals.! Circle 70 on inquiry card. AND STUFF Computer terminals, business systems, lab components . . . they all need desks and enclosures. That's what we're all about. Computer Furniture and Acces- sories offers a standard line of furniture suitable for a wide variety of applica- tions. Handsome, rugged, economical furniture in all shapes, sizes and colors. Basic models shipped from stock in days, not months. And we're nice people to deal with. What more could you ask for? CF*A Computer Furniture and Accessories, Inc. 1441 West 132nd Street Gardena, CA 90249 (213)327-7710 September 1979 © BYTE Publications Inc 161 TRS-80 SOLUTIONS ! BUSINESS Appointment log by M. Kelleher. Perfect for the professional. Accepts name and address, meeting start and endings, subject matter, derives elapsed time. For Level II, 16K $9.95 Payroll by Stephen Hebbler. Comprehensive 24 pg. manual with step-by-step instructions included in the package. Prints W2 and 941 information. Disk - $59.95. Mail List I by Michael Kelleher is the economy model of disk-based mailing list programs. Uses a single drive and handles up to 1400 names per disk, plus provisions for sorting options. 16K, D $19.95. | BUS-80 | | I The Business Software People® J Just about everything you need ... within 1 j year, participants receive programming for I i Inventory, Accounts Receivable, Accounts j Payable and General Ledger systems, plus I Payable and General Ledger systems, plus | Sales and Payroll. Complete documentation ' and software on diskette, $200.00 i ST 80 - Smart Terminal Lance Micklus Turns your TRS-80 into a computer terminal. Features include CONTROL key, REPEAT key, ESC key, RUN key and a functioning BREAK key. Lets you list incoming data on line printer. Reprogram RS-232-C switches from keyboard, making baud rate changes simple. Level II, 16K $49.95 ST80D Lance Micklus Contains extensions for disk drive systems to exchange files with a timesharing computer or another TRS-80. Can be customized fy redefining translation tables. Can transmit any type of TRS-80 ASCII file, also binary files. A practical, full-feature terminal program of professional quality. For 32K disk systems $79.95. Mail List II by BUS-80. Complete mail list system for dual disk. Enter, update, merge, sort, and print mailing labels. D, 32K $99.95 Small Business Bookkeeping by Roger W. Robitaille, is based on the Dome Bookkeeping Journal, sold for years in stationery and discount outlets. Level II, 4K with ($22.00) or without ($15.00) Dome journal. Small Business Bookkeeping For Disk by Miller Microcomputer Services and Roger W. Robitaille, Sr. Extended version. 32K Disk. With journal $31.95; without journal $24.95. Inventory S by Roger W. Robitaille, Sr. 240 stock items can be contained using the full 6 data areas and 2 pieces of alpha information. Level II, 16K $25.00 Inventory II. 2 Disk based program allows for creation, maintenance and review of over 2,000 items per clean diskette. Operates under Disk BASIC, DOS 2.1 with minimum memory allocation. D, $59.95 Electric Pencil by Michael Shrayer. A word processing system. Insertions, additions, deletions and corrections made more easily than with an editor's pencil. Perfect text printouts. Level II, 16K, $100.00. 32K Disk, $150.00 Accounts Receivable II by S. Hebbler. Does your billing, provides running balance, tracks overdue accounts, custom message printing option, much MORE. Requires 32K 2-disk system $79.95 General Ledger I by M. Kelleher. Establishes, defines, deletes and sorts up to 400 accounts. Up to 200 entries per session. For small-to-medium businesses not requiring double entry books. A com- prehensive, flexible accounting system. Requires 32K disk. $79.95. Inventory System 2.3 by M. Kelleher. One of small business management's most difficult problems brought under control. Keep current on price increases, shrinkage, low stock, profit margins. Program can handle up to 1,000 items per data diskette. Improved version, lower price. With documentation $99.95, 32K 2-disk. Text-80 by Frank Rowlett. Fully-documented text processing system for disk. Create, edit, move, delete, insert, change, print words or lines. D, 32K $59.95 8080-Z80 Conversion by M. Kelleher. Permits you to enter 8080 codings and returns the Z80 equivalent. L II, 16K $15.00 Basic Statistics by Steve Reisser. Pearson product- movement correlation coefficient, chi-square, Fisher T-test, sample analysis of variance, Z-scores and standard scores, with a random number generator built in to simulate data. L II, 16K $20.00 WANTED USED TRS-80 EQUIPMENT! We buy and sell used equipment Sample Prices: UNIT 4K Level I 16K Level II 6K Interface #1160 Disk Drive BUY SELL 275 350 500 650 175 225 300 399 CALL OR WRITE FOR DETAILS! NEW! ALL TRS-80 EQUIPMENT, 10% OFF! Factory sealed, with a Radio Shack sales slip and warranty! 16K Level II - $764.00, 16K Interface - $403.00 (plus shipping). Call Or Write For A Complete Price List. "NOW AN AUTHORIZED EXIDY DEALER" Step up to the amazing Exidy Sorcerer. Features high-resolution graphics, 64 x 30 character video, monitor and fast floating- point BASIC in ROM, user-definable charac- ter set, and the best keyboard of any micro. Sorcerer power can be yours for $995 [8K RAM], $1145 [16K], and $150 per 16K additional. A wide range of system and application soltware is also available. ! NEWDOS Apparat I M|jprildl DISK ERROR SOLVED! Stop blaming your I drive, fix your DOS with NEWDOS: an | | enhanced disk-operating system capable of I correcting over 70 errors in TRSDOS 2.1 to I i improve reliability, and key bounce, enable j DOS commands to be called from BASIC and j much more! Available NOW for 16K systems j with a minimum of 1 disk drive. $49.95 I NEWDOS + ( | Includes all the features of the original | j NEWDOS and adds 7 new utilities, including j I SUPERZAP, Disk Editor/Assembler, Dis- I j assembler, and Level I BASIC for Disk. j ! $99.95 ! ACTION GAMES Slalom by Denslo Hamlin. Choose between Slalom, Giant Slalom and Downhill. Level II. 16K $7.95 Air Raid by Small System Software. High speed machine language program with large and small aircraft flying at different altitudes. Ground-based missile launcher aimed and fired from keyboard. Planes explode when hit, cause damage to nearby aircraft. Score tallied for hits or misses. Level I or II, 4K $14.95. All Star Baseball by David Bohike, Level II, 16K $7.95 Batter Up by David Bohike. Level II, 16K $5.95 X-Wing Fighter II by Chris Freund. Piloting an X-wing fighter, you're out to destroy the Death Star! A new, improved version of an exciting space favorite. Level II, 16K. $9.95 Ten Pin by Frank Rowlette. A game of coordination, the scoring is true to the rules of the sport. Level II, 16K $7.95 Taipan by Art Canfil. Sail the China seas, dodging pirates and cutthroats, to make your fortune trading in arms and opium. Level II, 16K. $9.95. Balloon Race by Dean Powell. High above the Atlantic, your balloon must be cleverly maneuvered with the prevailing winds to reach Paris. Level II, 16K, $9.95. | ADVENTURES Scott Adams Feel as if you're manipulating HAL from 2001 when you play these machine language games. Hardly any rules, finding out is part of the fun. Two adventures on 32K disk, $24.95. Tape - choose from Land Adventure, Pirate's Cove, Mission Impossible, The Count, and Voodoo Castle - $14.95 each. DOG STAR ADVENTURE | Lance Micklus j You're trapped aboard an enemy battlestar [ ... can you find the gold, rescue the princess, I discover the plans and safely escape? Level j II, 16K $9.95. J Journey To The Center Ot The Earth by Greg Hassett. Excellent introduction to the excitement of ADVENTURE. Written in BASIC for ease of understanding, yet fast and fun!!. Level II, 16K tape $7.95. Amazin' Mazes by Robert Wallace. Ever -changing maze situation. Level II, 16K $7.95 Kamikaze by Russell Starkey. Command your ship against attacking suicide planes. Machine language graphics make this fast and fun! L II, 16K $7.95 Space Battles by Level IV. Assume the role of Galactic mercenary, roaming the universe in search of enemy aliens and the bounty you reap from destroying their ships! Danger, thrills, fast action — and financial headaches as wel I ! Features three levels of play, fast, machine language graphics, real-time input, Level II, 16KTapeor32K Disk. Tape -$14.95; Disk -$19.95. MISCELLANEOUS Diskettes Dysan 104/1 Box of five, $24.95 + $1.00 shipping. Verbatim, box of ten, $34.95 + $1.00 shipping/handling. Z80 Instruction Handbook by Scelbi Publ. $4.95 + $1.00 shipping/handling. The BASIC Handbook by Dr. David A. Lien $14.95 + $1.00 shipping/handling. Percom Disk Drives. Single or dual, for TRS-80's. Reliable, high quality, priced $100 lower than comparable units! Single drive -$399.00; Dual Drive - $799.00; Cable (required) - $29.95. Floppy Armour Protective envelopes for shipping floppy disks, of high-density, ultra-lightweight polymer. 5-pack, $4.95 + $1.00 shipping/handling f 16K MEMORY KITS Ithaca Audio 8 tested, guaranteed 16K RAM's, amazing low price - $99.95. 162 BYTE September 1979 Circle 313 on inquiry card. Electronics Assistant by John Adamson. Profession- ally written. Will draw sample schematics and help you design active and passive low-, band-, and high-pass filters, coils, attenuator networks, and three types of impedance-matching networks. Extensive graphics, one key selection routine. Level II, 16K -$9.95. SIMULATIONS 3-D Tic Tac Toe by Scott Adams. Three skill levels - author warns you to practice before tackling computer's third skill level. I or II, 16K $7.95 Star Trek III. 3 by Lance Micklus. One of the most advanced Star Trek games ever written. Level II, 16K $14.95. End Zone by Roger W. Robitaille, Sr. Authentic football simulation, right down to the 2-minute warning. Level I or II, 16K $7.95 Cribbage by Roger W. Robitaille, Sr. You versus the computer cribbage played by standard rules. Level I or II, 16K, $7.95. 'Round the Horn by Rev. George Blank. You're the captain of a clipper ship racing from New York to San Francisco. Level II, 16K $9.95 Concentration by Lance Micklus. One of the most popular television games. Level I or II, 16K $7.95 Safari by David Bohlke. You're in the running for a film contract at a major Hollywood studio. To qualify, you must photograph the most wild animals in their natural habitat. Level II, 16K $7.95. Pork Barrel by Rev. George Blank. Places you in the shoes of an aspiring Congressman. Level II, 16K $9.95 Backgammon by Scott Adams. Level II, 16K $7.95 Chess Companion by M. Kelleher. Combines chess clock features with ability to record your moves while action is fast and furious. Level II, 16K $7.95 Sargon Chess by Dan & Kathe Spracklen. Winner of the 1978 San Jose Microcomputer Chess Tourna- ment. Level II, 16K $19.95 Mastermind II. 2 by Lance Micklus. Lets you and the computer take turns making and breaking codes Level II, 16K$7.95 PERSONAL RPN Calculator by Russell Starkey. A self-document- ing calculator program. Uses Reverse Polish Notation with4-level stack, 100 memories, scientific functions. Level II, 16K $9.95 Home Financial Management by M. Kelleher. Turns your computer into a personal financial advisor. Level II, 16K$9.95 Tarot by Frank B. Rowlett, Jr. Probably the best future-gazing type program ever written. Try it - you'll like it! Level I or II, 16K $9.95 Ham Radio by M. Kelleher. Amateur Frequency Allo- cations, ID Timer, Q-signal File, Amateur Log Routine, Propogation Forecasting. L II, 16K $9.95. Special Disk-enhanced version, 32K $24.95 Educator Assistant by Steve Reisser. Five programs of value to educators. Compute percentage, individual student averages, class averages, standard test scores, final grades. L II, 16K $9.95 D, $14.95 Typing Tutor by 80 US. A set of programs designed to teach you touch typing. Takes you from basics to high-speed drill, with quizzes and grades. Progress at your own pace, and have fun mastering an enormously useful skill. Level II, 16K - $19.95. T|« TR5-80 Software Exchange 1*605*675.5144 17 BRIAR CLIFF DRIVE MILFORD, NEW HAMPSHIRE 03055 Personal Finance by Lance Micklus. 33 different budgets can be easily adapted by user to fit his individual needs. A 2-part program, entry and search. Level II, 16K $9.95 Advanced Personal Finance by Lance Micklus. Same as above with advanced analysis routine. Supports Disk Files D, 32K $24.95. UTILITIES KVP Extender by Lance Micklus. Corrects keyboard bounce, upper case lock, permits use as a terminal, screen printing. On tape ($24.95) or disk ($29.95) Level III Basic by Microsoft. The most powerful BASIC you can buy for the TRS-80 - in 5K of space, opens up fantastic new dimensions! 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Makes backup copies of object ("system") tapes. Features include copy, verify read, rename, verify write. No knowledge of machine language required. Level II, 16K $9.95. Magazine Section SoftSide, SoftSide is for pioneers . . . those hardy souls who have adopted a TRS-80, installed it in their living room or office, and unleashed their imaginations. SoftSide helps you discover the endless variety of tasks your new friend will do for you, as you build a unique partnership of human being and machine. We publish software for the partners. Every month we publish games, household applica- tion programs. Educational aids, business programs. We help you release your expecta- tions, fantasies, and dreams. SoftSide means Software! DEALER INQUIRIES INVITED Software and/or Magazines For further details call: 603-673-5144 = PROG 80 = A bi-monthly magazine for the serious programmer who wants to know HOW his computer works and WHY. PROG/80 empha- sizes technique rather than canned programs. The subjects include machine language, construction projects and specialized applica- tions software, not just for the advanced computer hobbyist, but for the computerphile who wants the most from his machine. flppleSeed If you're an Apple II pioneer, you've been longing for a software publication and hoping someone would get around to it. We have. Apple Seed is to the Apple II what SoftSide is to the TRS-80. And it's brand new. The first issue will roll off the press in September or October. Apple II enthusiasts will eat up this special introductory offer! SOFTSIDE □ 1 Year- 12 issues $18.00 PROG/80 □ 1 Year -6 issues $15.00 APPLE SEED □ 1 Year -12 issues $15.00 PO Box 68 Milford, NH 03055 D USA first class $25.00 - 1 yr. □ APO/OVERSEAS surface $25 - 1 yr. D CANADA/ MEXICO $25 - 1 yr. □ OVERSEAS airmail $30 - 1 yr. Exp. Date. Signature - Name Address City Interbank # [M/C only). .State. -Zip. Telephone orders accepted for Master Charge or VISA accounts. Call Monday through Friday, 9:30 to 5:30 EST at 603-673-5144 Circle 374 on inquiry card. BYTE September 1979 163 Circle 225 on inquiry card. ( SUPER SOFTWARE! MICROWARE 6800 SOFTWARE IS INNOVATION AND PERFORMANCE LISP Interpreter The programming language LISP offers exciting new possibilities for microcomputer applications. A highly interactive interpreter that uses list-type data structures which are simultaneously data and executable instructions. LISP features an unusual structured, recursive function- oriented syntax. Widely used for processing, artificial intelligence, education, simulation symbolic, and computer-aided design. 6800 LISP requires a minimum of 12K RAM. Price $75.00 A/BASIC Compiler The ever-growing A/BASIC family is threatening old-fashioned assembly language programming in a big way. This BASIC compiler generates pure, fast, efficient 6800 machine language from easy to write BASIC source programs. Uses ultra-fast integer math, extended string functions, boolean operators and real-time operations. Output is ROMable and RUNS WITHOUT ANY RUN-TIME PACKAGE. Disk ver- sions have disk I/O statements and require 12K memory and host DOS. Cassette version runs in 8K and requires RT/68 operating system. Price: Disk Extended Version 2.1 $150.00 Cassette Version 1.0 $65.00 A/BASIC Source Generator An "add-on" option for A/BASIC Compiler disk versions that adds an extra third pass which generates a full assembly-language output listing AND assembly language source file. Uses original BASIC names and inserts BASIC source lines as comments. SSB and SWTPC Miniflex version available. Price: $75.00 A/BASIC Interpreter Here it is— a super-fast A/BASIC interpreter that is source-compatible with our A/BASIC compiler! Now you can interactively edit, execute and debug A/BASIC programs with the ease of an interpreter— then compile to super efficient machine language. Also a superb stand- alone applications and control-oriented interpreter. Requires 8K RAM. The cassette version is perfect for Motorola D2 Kits. Price: $75.00 RT/68 Real Time Operating System MIKBUG— compatible ROM that combines an improved monitor/ debugger with a powerful multitasking real-time operating system. Supports up to 16 concurrent tasks at 8 priority levels plus real time clock and interrupt control. Thousands in use since 1976 handling all types of applications. Available on 6830 (MIKBUG-type)or 2708 (EPROM-type) ROM. Manual is a classic on 6800 real-time applications and contains a full source program listing. Price: RT68MX (6830) $55.00 RT68MXP (2708) $55.00 6800 CHESS A challenging chess program for the 6800. Two selectable difficulty levels. Displays formatted chess board on standard terminals. Re- quires 8K memory. Machine language with A/BASIC source listing. Price: $50.00 Our software is available for most popular 6800 systems on cassette or diskette unless otherwise noted Disk versions available on S.S.B.. SWTPC. or Motorola MDOS Please specify which you require. Phone orders are welcomed. We accept MASTERCHARGE and VISA. We try to ship orders within 24 hours of receipt Please call or write if you require addilional information or our free catalog Microware software is available for OEM and custom applications. IV! IC ROWA R F p ° B0X 4865 J.T I IV_> l\*^J TT/A.r\..E/ DES MOINES, IA 50304 SYSTKMS COKl'OKATION (515) 265-6121 Languages Fcpum Come From... continued R Lawrence Clark, 30303 Avenida de Calma, Rancho Palo Verdes CA 90274 While I applaud Mr Bass' attempts to improve the BASIC language ("Languages Forum," April 1979 BYTE, page 238), he has completely missed the point of the COMEFROM statement. The primary goal of the COMEFROM is to eliminate GOTOs, which Dijkstra and many other advocates of structured programming consider harmful. If the statement can also be used to trace back execution during debugging, that is an unex- pected bonus. I provided a detailed description of the semantics of the COMEFROM in "A Linguistic Contribution to GOTO- less Programming" (Datamation, December 1973). Brief- ly, the statement: destination COMEFROM source is equivalent to the conventional: source GOTO destination where both source and destination are line numbers. The original article describes additional variants, which in BASIC would appear as the following: IF condition COMEFROM source and: ON variable COMEFROM sourcel, source2, ... , sourceN Because of the COMEFROM's potential for improving programming accuracy and readability, I feel it is impor- tant to clarify its proper usage. ■ Languages Forum is a feature which is intended as an interactive dialog about the design and implementation of languages for per- sonal computing. Statements and opinions submitted to this forum can be on any subject relevant to its purpose of fostering discussion and communication among BYTE readers on the subject of languages. We ask that all correspondents supply their full names and addresses to be printed with their commentaries. We also ask that correspondents supply their telephone numbers, which will not be printed. 164 September 1979 © BYTE Publications Inc More on Multiple Conditions Scott Lawrence, 201B Lehman N SUCP, Potsdam NY 13676 David Faught's letter titled "On Expressing Multiple Con- ditions" in the December 1978 BYTE Languages Forum, page 176, does a good job of illustrating the need for a language construct to deal with actions based on multiple conditions. I, too, found the means available in BASIC, FORTRAN, and COBOL (I am not yet familiar with Pascal) somewhat lacking. This need is met, however, in PL/I by the SELECT group. The basic syntax of this construct is shown in listing 1. Listing i. SELECT (expression); WHEN (expression-1 , expression-2) action-1 ; WHEN (expression-3 action-2; OTHERWISE action-3; END; When the SELECT statement is executed, the expression in parentheses is evaluated and the value is saved. The expres- sions in the WHEN statements are then evaluated one at a time in the order in which they appear. As each one is evalu- ated, its value is compared to the saved value. If a value is found that matches the saved value, the action specified by that WHEN statement is executed and no further expressions are evaluated. If none of the values match, the action speci- fied by the OTHERWISE statement is executed. The actions after the WHEN and OTHERWISE statements may be a simple statement, a compound such as IF . . . THEN . . . , a group of statements within a DO or BEGIN block, a GO TO statement, a null statement, a subroutine call, or even another SELECT group. After the action has been performed, control passes to the first statement after the END (unless the action specifies otherwise, of course). If the expression in the SELECT statement is omitted, the expressions in the WHEN statements are treated as logical statements and evaluated as a bit string. If any bit in the string is 1 (signifying true), the action is performed. (A=B would be evaluated as a 1 bit if A and B contained the same value.) Listing 2 shows an example of such a SELECT group. Listing 2. SELECT; WHEN (A 36 MOS. LA36 DECwriter II S1,595 S 152 S 83 S 56 LA34 DECwriter IV 1 ,295 124 67 45 LA120 DECwriter III, KSR .... 2,295 219 120 80 LS120 DECwriter III, RO 1,995 190 104 70 LA180 DECprinter I, RO 1,995 190 104 70 VT100 CRT DECscope 1,695 162 88 59 VT132 CRT DECscope 1,895 181 97 66 TI745 Portable Terminal 1,875 179 98 66 TI765 Bubble Memory Term. . 2,795 267 145 98 TI810 RO Printer 1,895 181 99 66 TI820 KSR Printer 2,395 229 125 84 ADM3A CRT Terminal 875 84 46 31 QUME Letter Quality KSR 3,195 306 166 112 QUME Letter Quality RO 2,795 268 145 98 HAZELTINE 1410 CRT 895 86 47 32 HAZELTINE 1500 CRT 1,195 115 62 42 HAZELTINE 1520 CRT 1,595 152 83 56 Dataproducts 2230 7,900 755 410 277 DATAMATE Mini Floppy 1,750 167 91 FULL OWNERSHIP AFTER 12 OR 24 MONTHS 10% PURCHASE OPTION AFTER 36 MONTHS 61 \ ACCESSORIES AND PERIPHERAL EQUIPMENT ACOUSTIC COUPLERS • MODEMS • THERMAL PAPER RIBBONS • INTERFACE MODULES • FLOPPY DISK UNITS PROMPT DELIVERY • EFFICIENT SERVICE K J , ransNet Corporation 2005 ROUTE 22, UNION, N.J. 07083 201-688-7800 upon program correctness. A data-abstraction is defined as a data-structure and the set of operations that may be legally performed upon it. An example in the queuing theory context is the data-abstraction queue, for which a data-structure must exist to store its contents, and for which 5 operations are allowed: initialization, insertion, deletion, overflow, and underflow. The semantic mean- ing of these operations is also defined, but will not be repeated here so as to avoid duplication of the Gorney article. How is a queue to be implemented in a programming language? It would be simple if a programming language included a data-structure of type queue but, to my knowledge, none do. In general there exists an infinite number of data-structures of potential interest, and no language could include them all. Instead, any particular language usually includes only a small set of data-struc- tures such as reals, integers, and characters; and arrays, records, and files of these structures. No insurmountable problem exists, however, because a data-structure of in- terest can usually be constructed from these existing primitive data-structures. Thus one may construct a queue data-structure by using an array and 2 integers (head and tail pointers). Notice that the implementation of a queue data-struc- ture in the manner just described does not result in the data-abstraction of a queue: the program manipulating the array and the pointers is in no way restricted to the 5 legal queue operations. It is this lack of operation restric- tion that can result in program incorrectness, particularly in large programs undergoing maintenance. For example, because the data-structure is global(ie: exposed to the en- tire program) a "fix" for a particular problem may result in a new problem elsewhere within the program. Pascal addresses the data-abstraction concept directly by allowing the declaration of more than just variables (as opposed to other languages). This includes constant variables, which may never be the target of an assign- ment operation, and more importantly, the declaration of novel data types. For example in Pascal we might define waitingline to be a variable of type queue by the following: var waitingline : queue; Note that we might want more than 1 variable of type queue. This is allowed, as are the arrays of queues and so on. The contents stored within the queue may be items of type integer: var items : integer; However, they might be persons: var items : persons; Note that integer is a defined data-structure in Pascal, but that queue and persons are not. Before discussing this fur- ther, a comment on what advantage this brings the pro- grammer is appropriate. Recall the definition of a data-abstraction: a data- structure and the legal operations upon it. By writing procedures and functions for the legal operations upon a data-structure we are, in effect, implementing a data- 166 September 1979 © BYTE Publications Inc Circle 366 on inquiry card. Let your LSI -11* bret the 28K Karrier With our Bank -Switching family In LOCAL mode our memory is functionally just like DEC memory. But when you run out of memory space you're not lost. Add an inex- pensive Bank-Switch Controller (BSC-256) and you can go to two megabytes. Add another and go to four megabytes. So don't get boxed in with other brands of LSI-1 1 * memory. Break free. Join the family: RMA-032 32K by 16 bit RAM. $1200 On-board refresh (Single qty) 16K by 16 bit ROM. $300 (Intel 2716) (Single qty.) The Bank-Switch $300 Controller (Single qty.) RMS-016 BSC-256 Substantial quantity discounts are available. For a free copy of our Bank-Switching manual, call or write on your company letterhead. Digital Pathways Inc. 4151 Middlefield Road Palo Alto, CA 94306 (415) 493-5544 'Registered trademark of Digital Equipment Corporation DIGITAL PATHWAYS Circle 86 on inquiry card. BYTE September 1979 167 j 96 on inquiry card. use TRcopy WITH YOUR LEVEL II TRS-80* TRcopy is a cassette tape copying system that lets you SEE what your computer is reading. COPY ANY CASSETTE TAPE** With the TRcopy system you can copy any TRS- 80 Level II cassette tape whether it is coded in Basic or in machine language. You can also copy data created by programs and you can copy assem- bler listings. YOU CAN SEETHE DATA As the tape is being loaded, you can SEE the actual data byte-for-byte from the beginning to the end of the program. Up to 320 bytes are displayed at one lime. ASCII characters are displayed on the first line and hexadecimal code is displayed on the following two lines. Data is displayed exactly as it is input including memory locations and check sums. IDENTIFY PROGRAMS With TRcopy you can identify programs on cas- sette tapes without written documentation because you can SEE the filename. If you forget to label a tape, you can use TRcopy to display the tape contents and identify the cassette. VERIFY CASSETTE TAPES With TRcopy you can verify both the original tape and the tape copies. You can make certuin that your machine reads the original tape correctly and that It makes byte-for-byte copies. TRcopy also counts as it reads giving you the exact length of the data. MAKE BACKUPS FOR YOUR PROGRAMS Now you can make backup copies of yourvaluable programs. Many times a cassette that you make will load belter than one that is mass produced. The original can then be kept as a backup in case the copy is damaged. MAKE COPIES OF YOUR SOFTWARE If you are in Ihe software business you can use TRcopy to make tested copies of your programs for sales distribution. TRcopy produces machine lan- guage tapes that are more efficient than those pro- duced by the assembler itself. RECOVER FAULTY DATA With TRcopy you can experiment with the volume and level controls and you can SEE whalLhe computer is reading — even if your computer will not read Ihe data through normal read instructions! In this way it is possible to reud and copy faulty tapes by adjusting the volume control until you SEE thai the dala is input properly. SIMPLE -FASCINATING -FUN TRcopy is not only a practical utility program.lt is also a fascinating graphics program that lets you SEE, for the first time, cassette data as your com- puter is reading it. And it's as simple as 1-2-3. Just load, verify and copy. You will now be able to use cassette tapes with confidence knowing that TRcopy is there when you need it. The TRcopy system is a machine language program with documentation explaining tape leaders, sync bytes, check sums and other formatting conventions. 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This is accomplished by declaring data-structures at a level above variables: type persons = . . . queue = . . . Here the dots indicate the data-structures necessary to implement the type in Pascal. For example, in the queu- ing theory context, we might have: type queue = record head, tail : . . maxlength; full, empty : boolean; contents : array [0 . . maxlength] of integer; end; Here maxlength is a constant declared earlier in the pro- gram which indicates the legal subrange of the integer variables head and tail (used as pointers); full and empty are logical variables indicating the status of the queue; and contents is an array storing the contents of the queue. In this case the queue is storing integers, but it need not — it could just as well be persons: contents: array [0 . . maxlength} of persons; Of course, the meaning of persons would have to be declared earlier within the type statement for this to be legal Pascal. After the user declared data-structures are defined, variables of these types can be declared as follows: var waitingline : array [1 . . 3] of queue; teller 1: queue; These 4 queues are restricted to the definition of queue as shown above. If necessary, we might declare more than 1 type of queue (ie: storing a different type of contents) if the problem context makes that appropriate. Listing 1 shows Pascal procedures and functions im- plementing the 5 legal queue operations. Note that the parameters are a and b. A change of the b type declara- tion is all that is necessary to make these programs workable for a different type of contents. An important point: there is no need to initialize the contents of the queue to a particular value and use this value to decide how to manipulate the pointers, as is implied by the Gorney article. In fact, by doing so a programmer is sow- ing the seeds for future disasters. If Mr Gorney 's queue is ever exposed to a value of -9, the program may fail. Clearly, making correct operation dependant upon the avoidance of certain potentially legal entries into the data structure is not good programming practice. At this time it is informative to step through the BASIC language equivalents in the Gorney article using some trial data. The complexity of program execution flow 168 September 1979 © BYTE Publications Inc 32K Board Pictured Above New RAM Prices. From The Dynamic Memory Company. 16K— $249 48K— $500 32K— $375 64K— $625 Ever since we started making these memory boards over a year ago we have continued to lower our prices to stay competitive. Due to your confidence in us, we are again able to lower our prices! Our reliability has been proven by months of superior performance in thousands of installations. Our low-power boards are being used by quality-minded systems manufacturers across the country and overseas. 4MHz boards now available. 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This is true even though the respec- tive procedures do nothing for these operational mistakes. Listing 1: This simple Pascal program defines the data type queue and then describes the 5 legal operations on that data type. procedure initialize (var a : queue); begin a. head : = 0; a. tail : = 0; a. full := false; a.empty : = true; end; {of initialize} procedure insert (var a : queue; b : integer ); begin with a do if not full then begin empty : = false; contents [tail] : = b; tail:= (tail + 1) MOD (maxlength + 1); if tail = head then full : = true; end; end; {of insert] procedure delete (var a ; queue; var b : integer ); begin with a do if not empty then begin full : = false; b := contents [ head ]; head : = (head + 1) MOD maxlength + 1); if head = tail then empfy := true; end; end; {of delete} function fullq ( a : queue ) : boolean; begin if a.full then fullq : = true else fullq : = false; end; {of fullq} function emptyq (a : queue ) : boolean; begin if a.empty then emptyq := true else emptyq := false; end; {of emptyqs} 170 September 1979 © BYTE Publications Inc Circle 394 on inquiry card. Circle 205 on inquiry card. Listing 2: The data stack can also be defined in a Pascal pro- gram. It is left as an exercise to the reader to translate this pro- gram into BASIC or FORTRAN and compare the understand- ability of the 2 programs. type stack = record top : 1 . . maxlength; full, empty : boolean; contents : array [1 . . maxlength] of integer; end; procedure initialize (Var a : stack ); begin a. full := false; a.empty : = true; a. top : = 1; end; {of initialize) procedure push (var a ; stack; b : integer); begin with a do if not full then begin empty : - false; contents [top] : = b; if top < > maxlength then top : = top + 1 else full : = true; end; end; {of push] procedure pop (var a ; stack; var b : integer ) : boolean; begin with a do if not empty then begin full ; = false; b : = contentsftop]; if topo 1 then fop ; = top - 1 else empty ;= true; end; end; {of pop) function fullstk ( a : stack ) : boolean; begin if a.full then fullstk := true else fullstk ;= false; end; {of fullstk) function emptystk ( a : stack ) : boolean; begin if a.empty then emptystk : = true else emptystk := false; end; {of emptystk) In summary, the data-abstraction is an important con- cept that greatly enhances program correctness. The Pascal programming language includes this concept; BASIC does not. My point again: the simplicity of BASIC is a red herring — it encourages sloppy program- ming and error-prone programs. A contemporary lan- guage like Pascal is explicity designed to encourage error- free program development, therefore it is worth learning and using. One more point: experienced Pascal program- mers know that the language includes pointers as a data type so the queue data-abstraction could be implemented even more easily than shown here. This particular method was chosen to correspond to the approach taken by the Gorney article. Just as a queue is an FIFO (first in, first out) data- abstraction, a stack is an LIFO (last in, first out) data- abstraction. Listing 2 shows a Pascal type declaration and the subroutines that are necessary to implement the legal operations upon a stack. These are included in the hope that readers may implement this data-abstraction in BASIC or FORTRAN and then compare for themselves the relative merits of these 2 languages to Pascal. ■ DISCOUNT PRICES Microcomputers & Peripherals ITS YTES 00 KS ARGAINS _/ Mm \ |h| Illl ~ih. [a_ Cromemco • SWTPC • Lear-Siegler Hazeltine • RCA • North Star Verbatim • Perkin Elmer and others Fast, off the shelf delivery. Call TOLL FREE 800/523-5355 MARKETLINE SYSTEMS, Inc. 2337 Philmont Ave., Huntingdon Valley, Pa. 19006 215/947-6670 • 800/523-5355 Dealer Inquiries Invited on ALL Computers, Peripherals, Software, and ALL other fine Radio Shack® products. Radie/haelt Authorized Sales Center 11 17 CONWAY MISSION, TEXAS 78572 (512) 581-2765 VISA' NO TAXES on out-of-state shipments. FREE Surface delivery available in the U.S. WARRANTIES will be honored by your local Radio Shack® store. Circle 314 on inquiry card. September 1979 © BYTE Publications lnc 171 MAXIMUM VALUE FOR YOUR DOLLAR NORTH STAR COMPUTER PRODUCTS HORIZON1 16K KIT $1275.00 1 6K RAM BOARD KIT $ 250.00 32K RAM BOARD KIT $ 475.00 VERBATIM DISCS FOR NORTH STAR BOXOF10 S29.POSTPAID COMPLETE SYSTEMS AVAILABLE CUSTOM SOFTWARE FOR NORTH STAR SYSTEMS CASIO CALCULATORS AT DISCOUNT PRICES MANY OTHER SUPER VALUES WRITE OR CALL: A.E.I. 3851 HACKETT AVE. LONG BEACH, CALIF. 90808 (213)421-4615 (213)429-0535 SURPLUS ELECTRONICS ASCII ASCII IBM SELECTRIC BASED I/O TERMINAL WITH ASCII CONVERSION INSTALLED $645.00 • Tape Drives • Cable • Cassette Drives • Wire • Power Supplies 12V15A, 12V25A, 5V35A Others, • Displays • Cabinets • XFMRS • Heat Sinks ■ Printers • Components Many other items Write for free catalog WORLDWIDE ELECT. INC. 130 NORTHEASTERN BLVD. NASHUA, N.H. 03060 Phone orders accepted using VISA or MC. Toll Free 1-800-258-1036 In N.H. 603-889-7661 MORE INNOVATIONS! FROM P.S. SOFTWARE HOUSE FORMERLY PETSHACK PET' INTERFACES PET " SCHEMATICS '.nil ONn^s.7.1 *i .YOU GET Monitor and rape Ri'curch" riius compute f>,-»ts layout a" i p.1iriSI,lkir>f|ly draWI in !»'-' rnniijIi-M rlKlail PET " ROM ROUTINES jfQP ON LY $19 95 YOU GET Complr-* 0>5.1S5pmbiy iclirais nl .ill / ROMS plus .eler.nr.ea v, points Video MnniiiM Ki'ybo.irn regime Tape Recoftf oral PtaytMC I.me Clock 0M Toi-nlici' you wi' ,in' ,nsn I'lfimlmc] (Hit ownM.ic' Mnnilor program tor your CE T u".inn« welcome P.S. SOFTWARE HOUSE P.O. Box 966 Mishawaka, IN 46544 CC Tel: (219) 255-3408 2E Circle 21 on inquiry card. Circle 391 on inquiry card. Circle 315 on inquiry card. Metnorex Floppy Discs Lowest prices. WE WILL NOT BE UNDERSOLD!! Buy any quantity 1-1000. Visa, Mastercharge accepted. Call free (800)235-4137 for prices and information. All orders sent postage paid. PACIFIC EXCHANGES 100 Foothill Blvd. San Luis Obispo. CA 93401. (In Cal. call (805) 543-1037.) Circle 294 on inquiry card. 6800/6801 MICRO SOFTWARE * * * CROSS SOFTWARE * * * 6800/6801 assembler .... $ 800 PL/W compiler $1400 cross linker $ 400 math/science $ 500 simulator $ 800 * * * RESIDENT SOFTWARE * * * editor/assembler $ 95 industrial 4K BASIC $ 95 in ROM $299 WINTBK Corp. 317-742-6802 902 N. 9th St., Lafayette, IN 47904 Vne. 7nd<2pendenH7eu>s)eliizr oi- nea-rb Co. Computers ^.a-rur tzd-tufes Hardware modifications developed bu readers Compatible parckvare and software from other vendors advance inA>fma-hon on "Benton Harbor plans nepor-ts of" us.-e.r-s experiences yuity their Sustems ji— /ji / %'ftiumenttote 12 issuer $8% (114 overseas.) m U.S. funds 2#iss UK -.|^5(|25 overseas) P^Lk "Back issues (about?) included on request 325-3 Kennsulvania flve., S. £. lUas^inafon, V.C 2 0003 Circle 389 on inquiry card. Circle 32 on inquiry card. SHORT CASSETTES C-10 50 FEET List SLOP 10 for $7.50 50 for $32.50 MICROSETTE CO. ' 777 Palomar Ave. • Sunnyvale. CA 94086 Duplication Services Microsette also offers professional duplication services for Commo- dore PET and Radio Shack TRS-80 Level I and Level II cassettes. Our service provides mastering, quality control, all material including two- piece box, affixing of your labels or supplying our blank labels and ship- ping. Prices start at $2.00 each in 100 quantity. MICROSETTE CO. 777 Palomar Ave. ■ Sunnyvale. CA 94086 ; BYTE's New Toll-free ; ^ Subscriber ; W.A.T.S. Line ! (800) 258-5485 i ' To further improve service to i our customers we have installed ' a toll-free WATS line in our , Peterborough, New Hampshire ' office. If you would like to order , a subscription to BYTE, or if you ' have a question related to a BYTE . subscription, you are invited to ; call (800) 258-5485 between '< 8:30 AM and 4:30 PM Eastern ' Time. This applies to calls from . within the continental US only. \ i--"" > We thank you arid lo6k forward to serving you. "CRT INTERFACES-' black > white /color Monitors * Combination Rcvr 'monitor sets " Modulator kits * B-W Cameras " Color Cameras " Audio Subcarrier kits * Parts WRITE or PHONE for DETAILS S PRICING. DIAL: 402-987-37711 Dealers welcomed. Well established program. to rA-l 13-B ATV Research Dakota City, Broadway ., g^Kj NE. B873f Circle 218 on inquiry card. Circle 19 on inquiry card. GODBOUT .SLASHES STfiTiC MEMORY PRICES fjGfilD: Econoram * unkits are now at their lowest prices ever. What's an "unkit"? It's a standard Econoram board that has all sockets and bypass caps pre-soldered in place. To complete assembly, the user simply solders in a few other parts, and inserts all ICs into their sockets. The result: A one-evening project that saves money while offering true CompuPro/Econoram quality for those on a budget. Static technology used throughout; all boards except Econoram VI run with 4 MHz systems. Same 1 year limited warranty, same great specs as our regular boards. Speaking of regular boards, we offer assembled /tested models and boards qualified under our high-reliability Certified System Component (CSC) pro- gram (200 hour burn-in, immediate replacement in event of failure within 1 year of invoice date). Refer to chart below for pricing. SI iii^-9 l SiS i iN Name Storage Buss Configuration Unkit Assm CSC Econoram HA 8KX8 S-100 2-4K blocks $149 $179 $239 Econoram IV 16KX8 S-100 1-16K $269 $329 $429 Econoram VI 12KX8 H8 1-8K, 1-4K $200 $270 n/a Econoram VIIA-16 16KX8 S-100 2-4K, 1-8K $279 $339 $439 Econoram VIIA-24 24KX8 S-100 2-4K, 2-8K $398 $485 $605 Econoram IX- 16 16KX8 Dig Grp 2-4K, 1-8K $319 $379 n/a Econoram IX-32 32KX8 Dig Grp 2-4K, 1-8K, 1-16K $559 $639 n/a Econoram X 32KX8 S-100 2-8K, 1-16K $529 $649 $789 Econoram XI 32KX8 SBC 2-8K, 1-16K n/a n/a $1050 BANK SELECT MEMORIES (for Alpha Micro Systems, Marinchip, etc.) Econoram XII-16 16K X 8 S-100 2 ind. banks** $329 $419 $519 Econoram XII-24 24K X 8 S-100 2 ind. banks** $429 $539 $649 Econoram XIII 32K X 8 S-100 2 ind. banks** $559 $699 $849 'Econoram is a trademark of Bill Godbout Electronics * 'Econoram XII-16 and -24 have 2 independent banks addressable on 8K boundaries; Econoram XIII has 2 independent banks addressable on 16K boundaries. — Did someon e say extended addressing? 16 bit CPUs? All we'll say is that Econoram XIV is coming soon — 1 16K MEMORY *' EXPANSION SET — was $109, now only $87.20! And that's for a Godbout quality pro- duct. DIP shunts included, 250 ns chips, and crystal-clear instructions make expan- sion a snap in Radio Shack-80, Apple, and Exidy Sorcerer computers. Low power chips used exclusively. ••••••••••••••••• ECONORAM II V 18 SLOT *• CLOSEOUT-$ 129 unkit I MOTHERBOARDS (3/ $375), $155 assm I UNKIT CLOSEOUT - was $124, t This is a limited quantity item — first come, first served. Our brand new Econoram HA is out, but even by today's standards the original Econoram II is an excellent memory. 2 MHz operation, low power, configuration as two inde- pendent 4K blocks, and one of the best track records in the industry for reliable and cost- effective operation. Easy one-evening assembly, 1 year limited warranty on all components. ••••••••••••••••••••••A now only $109 With all edge connectors pre-soldered in place for painless assembly. Includes on board active termination. Coming soon: new 12 slot motherboard and an 18 slot double terminated model that can han- I die 12 MHz CPUs! , ••••••••••••••••• OTHER COMPUTER PRODUCTS: 2708 EROM BOARD UNKIT $85 4 independently addressable 4K blocks, with selective disable for each block. Built to CompuPro/Econoram standards (dipswitch addressing, top quality board, sockets wove -soldered in place), and includes dipswitch selectable jump start built right into the board. Includes al! support chips and manual, but does not include EROMs. ACTIVE TERMINATOR KIT $34.50 As written up by Craig Anderton in the April '79 issue of Kilobaud Microcom- puting. Our much imitated design plugs into any S-100 motherboard to reduce ringing, crosstalk, noise, and other buss-related problems. TERMS: Cal res add tax. Allow 5% ship- ping, excess refunded. VISA* /Master- charge^ call our 24 hour order desk at (415) 562-0636. COD OK with street ad- dress for UPS. Prices good through cover month of magazine. Circle 150 on inquiry card. (ompuPro Box 2355, Oakland Airport, CA 94614 "INTERFACER" S-100 I/O BOARD $189 unkit, $249 assembled and tested. Dual serial port with 2 full duplex parallel ports for RS-232 handshake; EIA232C line drivers and receivers (1488, 1489) along with current loop (20 mA) and TTL signals on both ports. On board crystal controlled timebase with independently selectable Baud rate generators for each part (up to 19.2 KBaud). This board has hardware LSI UARTs that don't tie up the computer's CPU. operates with 2 to 5 MHz systems, includes software pro- grammable UART parameters/ interrupt enables/handshaking lines, offers provi- sion for custom frequency compensation on both receive and transmit sides to ac- commodate varying speed/noise situations or unusual cable lengths . . . and even all this isn't the full story on what this no-excuses board can do for you. We think this product is a real winner; check one out in person, you'll see what we mean. from (PGUP ELECTRONICS FREE FLYER: Weil be giad to tell you more than the space of this ad permits. Just send your name and address, we'll take care of the rest. If you're in a hurry, enclose 4K in stamps for 1st class delivery. BYTE September 1979 173 SAVE MORE THAN 20% NORTH STAR - INTERTUBE THINKER TOYS - HUH THE SMARTEST COMPUTERS AT THE SMARTEST PRICE DOUBLE DENSITY HORIZON H6K KIT LIST $1599 $1274 ASSEMBLED & TESTED $1899 $1519 H0RIZ0N-2-32K KIT $2249 $1799 ASSEMBLED & TESTED $2549 •2039 HORIZON 2-32K QUAD DENSITY ASSEMBLED & TESTED $2999 $2399 PASCAL FOR NORTH STAR ON DISK $49 POWERFUL NORTH STAR BASIC FREE THINKER TOYS DISCUS/2D $1149 $949 MEASUREMENT SYSTEMS ASM MEMORY 64K •649 TOP DUALITY + TOP SPEED + LOWEST PRICE INTERTUBE II SMART TERMINAL $995 $780 TRS-80 TO S-100 HUH KIT $295 • 260 ASSEMBLED & TESTED $375 •350 HUH MINI 8100 KIT $115 • 103 ASSEMBLED 8i TESTED $155 • 139 MARYELLEN WORD PROCESSOR $3B BEST FEATURES OF IBM & NORTH STAR VERBATIM DISKS •29 WHICH COMPUTERS ARE BEST? BROCHURE FREE AMERICAN SQUARE COMPUTERS KIVETT DR * JAMESTOWN NC 27282 (919)883 1105 Circle 16 on inquiry card. SOFTWARE FOR APPLE IE All programs on high quality cassette tape, ready lor use on any Apple II System with Applesoft Liberal use ot prompting allows easy use even lor the novice MATRIX MANIPULATION: Compules inversion, de- terminate, and solution of linearly independent simul- taneous equations Also performs matrix mullipiica- lion division, addition & subtraction 8K - 117.50 TRIANGLE SOLUTIONS: Computes unknown quan- tities (including area) for any triangle Also compules area of any polygon 8K - 115.00 INVESTMENT A MORTGAGE MANAGEMENT: Just the program for the homeowner, small investor or business executive faced with difficult tinancial de- cisions Computes amortization schedule, present or luture values of a series of cash Hows, days betweei. dates, plus more 8K - $17.50 COMPUTER CAJUN CUISINE: Program computes exact amounts of all ingredients necessary tor any number of servings for eight Louisiana soup and gumbo recipes 16K - $25.00 Send check or money order to: TECHNICAL SOFTWARE INC P O Box 73043 Melaine, Louisiana 70033 THE COMPETITION is south of the border WHAT ARE THEY UP TO NOW? Microprocessor sales in LATIN AMERICA are going to take off in the next decade. Let me help you research the market, set up dealer/distributorships, establish joint ventures, or even your own manufacturing/assembly plant. I am a multi-lingual, scientifically- trained, international marketing ex- ecutive (USA national) who is going to head up an expansion into Latin America for an aggressive microprocessor/mini- computer manufacturer — will it be for you? I plan to visit the USA shortly and can meet you. Roy J. Canon 22/23 Old Burlington Street, London W1X 1R1. England. Circle 41 on Inquiry card. PRECISION MICROCOMPUTER POWER SUPPLY MODEL MP04 $169 4 OUTPUTS: 5V a 4A -5v a . 1A 12V a . SA -12V a . 5A FULLY REGULATED CURRENT LIMITED ASSEMBLED AND TESTED Send check or money order to SONTEX. INC 12022 Sturdivont Stafford. TX 77477 Texas residents add 5/£ sales tax DOCUMENTATION PROBLEMS? SOLVE THEM WITH TEXTWRITER® THE ULTIMATE TEXT FORMATTER FOR REPORTS • AUTOMATICALLY PRINTS A TABLE OF CON- TENTS AND AN ALPHABETIZED INDEX • ALLOWS MULTIPLE I OOTNOTES PER PAGE FOR FORMLETTERS • INSERTS NAMES AND ADDRESSES I ROM A MAILING LIST OR I ROM THE KEYBOARD •LINKS PILES TOGETHER BY CHAINING OR INSERTING OTHER FEATURES • RIGHT AND LEIT JUSTIFICATION, PAGINATION. PAGE AND CHAPTER NUMBERS. PAGE HEAD- INGS AND LOOTINGS. CENTERING, UNDER- LINING, AND CONDITIONAL PAGINATION •WORKS WITH ANY TERMINAL AND PRINTER VERSIONS • FOR CP/M®ON 8" IBM, TRS-80® NORTH STAR, AND MICROPOLIS • I OR MICROPOLIS MDOS OR NORTH STAR DOS SI25 EOR TEXTWRITER III - REQUIRES 32K SYSTEM S75 FOR TEXTWRITER II -WITHOUT REPORT FEATURES ORGANIC SOFTWARE 1492 Windsor Wav • Livermorc CA 94550 1415)455-4034 Circle 295 on inquiry card. tinyFORTH tlnyFORTH is the cassette oriented version of the dictionary based computer language called FORTH. tlnyFORTH includes these FORTH features: s Dictionary-oriented structured high-level language *• Built-in assembler and text editor ^ Interpreter for quick program de- velopment s Compiler for fast execution ^ tinyFORTH and FORTH programs are inter- changeable s Cassette tape input and output s Enhanced graphics s Faster & more powerful than level II BASIC ^ More compact programs than BASIC ^ Easy to use. tlnyFORTH cassette for TRS-80 and full docu- mentation $29.95 Documentation only $ 9.95 All orders are fully guaranteed. Add S1.50 for postage and handling. Order with check, money order. Visa, or Mastercharge. Specify TRS-BO level when ordering. The Software Farm Box 2304A1 Reston, VA 22090 Circle 365 on inquiry card. Circle 351 on inquiry card. Circle 333 on inquiry card. 6800 BASIC CROSS REFERENCE Greatly reduces the time to examine and modify a BASIC program with this com- plete CROSS REFERENCE listing of a BASIC program. Reads a BASIC program from disc and selectively provides source listing and complete SORTED CROSS REFERENCE of all VARIABLES - FUNCTIONS ■ GOTO and GOSGB statements. Program is written in assemble using SMOKE SIGNAL MINI DISK SYSTEM. Specify as either TSC or CO-RES assem- ble source format. Complete source and object is on a 5Va mini diskette for $ 1 4.95. FRANK SCHIELE 1375 TOBIAS DRIVE CHCILA VISTA CA. 9201 1 HAZELTINE 1400 only $649.95! » Verbatim Mini Diskettes . . . . . . $3.70 each (boxes of 1 0) • Intertube . . $784.00 • TRS-80 1 6K Level II Expansion Kit $89.95 • Centronics 779 tractor .... $1050.00 • Horizon II ass. . . . $1999.00 ■■p Mail TORA SYSTEM INC. -| Order 2 9-02 23rd Avenue Only. Astoria NY 11105 (212) 728-5252 ENGINEERING PROGRAMMERS Don't Come To Mass... Unless you enjoy challenging micro software development projects with some of the fastest growing commer- cial systems manufacturers in the U.S. Our clients offer generous salaries, flexible hours, profit sharing, etc. to experienced or degreed assembly programmers in areas such as communications, diagnostics, text editing, graphics, compiler, and O.S. design. Starting salaries 18-28K. All fees, relocation and interviewing expenses assumed by the companies. Please contact Dave Adams (617) 246-2815 (collect calls accepted). N.E. Recruiters, 6 Lakeside Office Park, Wakefield, MA 01880. Fee paid consultants Circle 329 on inquiry card. Circle 357 on inquiry card. *\ FOR THE VERY BEST IN NORTHSTAR® COMPATABLE SOFTWARE BUSINESS CRS - Cliant Record System. A complete program package for the Insurance agent. CRS will provide you with very fast online access to your client records, print reports and mail labels, and give you all the information you will need to increase your sales through the use of CRS as a MARKETING TOOL. CRS stores a complete record for each client that includes the name, address, telephone #, as well as provisions for customer #, salesman #and up to six policies (expandable if needed). The policy information is complete with both the type of converege and the company that is underwriting it, as well as exp. date, premium, tarm, and payment schedule. You also have a remark field. You can search the files by any field, and CRS supports a powerful 'sieve' search to provide you with all the information you need to increase insurance sales. CRS comes with two|2} users manuals, one for the owner, and one for office personnel! (minimal system: one drive, 40K RAM starting ZQOOH) $250.00 (manual: $40.00) TEXT PROCESSORS TFS - Text Formatting System. At last a full featured text processor for NorthSter that you can rely on! TFS has left & fight margin justification, page numbering, chaptering, page headings, centering, paged output & MORE. Supports powerful text manipulations including: global & local 'search and change,' file merges and block moves. This means that you can restructure your text file at any time to look the way you want it to, you can even 'chain' files together from disc for documents larger than your current memory. TFS is completely load and so' therefore you can start using it at once. You get two(2) users manuals: one is a Quick Start manual to get you going in minutes, the other is an in depth study of TFS. (TFS requires RAM from 0O0OH to 2D0OH) $75.00 (manual only: $20.00) ASSEMBLERS ARIAN - A complete 8001) assembler that interfaces directly to your DOS. ARIAN is completely 'load and go'. Features include: dynamic file and RAM allocation, custom disc and RAM commend cap ability, several library routines directly accessable by the user. Also, a complete text editor, and system executive. ARIAN is both powerful and easy to learn and use; it is an assembler that you can grow with. Comes complete with a 51 page users manual (ARIAN requires RAM from 0O00H to 2000H) $50.00 (manual alone: $10.00) ARIAN Utility Package -Several disc based utilities. Includes a complete DEBUG Package: $50.00 PROGRAMMING LANGUAGES 'Tiny' PASCAL - This is the famous Chung/Yuen Tiny' PASCAL. FAST • ELEGANT - STRUCTURED. Local and global variables plus procedure and function independence make Tiny' PASCAL grBBt for high spooif applications. Compiles to 8080 code that executes up to 25 times faster than BASIC. You also rocieve SOURCE to Tiny' PASCAL written in PASCAL. This means that you can compile the compiler! Add features, relocate, etc. (you will need 36k to do this) $40.00 n C n r UTILITIES U t B E - (Does Everything But Eat!) This is a must for NorthSter users. You can: COMPACT & EXPAND BASIC programs. Compacting removes unnecessary spaces and remarks. This saves memory and makes for programs run faster. Expanding puts them back again. Cross-reference BASIC programs by variables and transfer statements. Global substitutions of variable names in BASIC programs. Formatted print outs of BASIC programs as well. $40.00 SPECIFY SINGLE OR DOUBLE DENSITY ALL ORDERS PREPAID OR C.O.D. ILLINOIS RESIDENTS ADD 5% SALES TAX P.O. Box 1628 Champaign, IL 61820 (217) 344-7596 68 MICRO JOURNAL * 5! * * THE ONLY 6800/09 USER-ORIENTER MAGAZINE Months ahead of all others with 6800/09 articles & new products Crunchers Corner — Bryant (A monthly programming tutorial) * Flex" to BFD — Puckett * Tiny Music — Thompson * Semiconductor, Part 1 — Kinzer * Soup Up Your TVT — Pass « Hints & Kinks — fixes (soft & hard) * 50 pages plus Each Month! Crunchers Corner — Bryant * A Look at the SWTPC CT-82 — Ferguson * 6800 Relative Branch Calculation (Hand) — Berenbon « Relative Calculator (Machine) — Heatherington * Maillist (Disk) — Lilly * Modems — Schuman * Semiconductor - Part 2 — Kinzer * Locate — Pigford * A20 MA, Printer-SWTPC — Perdue * AS-50 Monitor Board — Pentecost * TSC Basic for 6800 — Shirk * Plus Much-Much More! Crunchers Corner — Bryant « A Case forthe Small DOS — Mauch * MF-68 Motor Fix — Sorrels * Transfer (FLEX 1 to 2 or 5) — Womack « 6800 Delay — Beren- bon * Make Like a 6809 — Fein- tuch * Games (Basic) — Harmon * Boot (Flex-BFD) — Puckett * Freeze Display (SSB) —Johnson * Paper Tape Reader — Adams * FLEX'" Fixes and Much More! P3ul MAGAZINE COMPARISON (2 years) Monthly Averages 6800 Articles KB 7.8 TOTAL PAGES- BYTE CC DOBB'S 6.4 2.7 2.2 19.1 ea. mo. Average cost for all four each month: $5.88 (Based on advertised 1-year subscription price} 68' cost per month: $1 21 That's Right! Much. Much More for About 1/5 the Cost! EFFECTIVE SEPT. 1, 1979 1-Year $14.50 2 Years $26.00. 3 Years $36.50 OK, PLEASE ENTER MY SUBSCRIPTION Bill My: Master Charge □ — VISA r" Card — Exp. Date For □ 1-Year p 2 Years □ 3 Years Enclosed: $ Name City -Zip My Computer ls:_ 68 MICRO JOURNAL 3018 Hamill Road HIXSON, TN 37343 FOREIGN ADD: $9.50 Per Yr. Surface $26.50 Per Yr. Air Mail • MORE 6800 ARTICLES THAN ALL OTHERS COMBINED* Circle 337 on inquiry card. BYTE September 1979 175 Circle 236 on inquiry card. IMMEDIATE DELIVERY Domestic & Export DEC LSI -11 COMPONENTS A full and complete line with software support available. mini Computer Suppliers, Inc. 25 CHATHAM ROAD SUMMIT, NEW JERSEY 07901 SINCE 1973 (201) 277-6150 Telex 13-6476 APPLE • CENTRONICS • TEXAS INSTRUMENTS HORIZON • VECTOR GRAPHIC • CROMENCO • RADIO SHACK • HP^r ■» '^QPOLIS • SOROC • OSI • SWTP • j^jjf %W fejBM • NEC PET -DIABLO^! 1 gj NMZELTINE WANG WE'VE GOT YOU COVERED! Cover Craft Dust Covers protect your hard- ware and your investment. Save mainte- nance, downtime and look great. Our Dust Covers come in hundreds of sizes each cus- tom designed to fit a particular model of termi- nal, CPU, Line Printer, Floppy Disk. They're a proven way to help eliminate dust and dirt accumulation, improve system reliability and save many times the cost in reduced mainte- nance and downtime. What's more, your satisfaction is 100% guaranteed Cover Craft Dust Covers are available from your local computer retailer * * Q( - *q q R or contact Cover Craft. 9O.yO-9y.rO Can you afford fo wait any longer? C COVER CRAFT P.O. Box 555, Amherst, NH 03031 Telephone (603) 673-8592 Event Cueoe In order fo gain optimum coverage of your organi- zation's computer con- ferences, seminars, work- shops, courses, etc, notice should reach our office at least three months in advance of the date of the event. En- tries should be sent to: Event Queue, BYTE Publications, 70 Main St, Peterborough NH 03458. Each month we publish the current contents of the queue for the month of the cover date and the two following calendar months. Thus a given event may ap- pear as many as three times in this section if it is sent to us far enough in advance. SEPTEMBER 1979 September 4-6 International Conference and Exhibition on Engineer- ing Software, University of Southampton, England. The aim of this conference is to provide a forum for the presentation and discussion of recent advances in engineering software and to present a state-of-the-art in this field. The exhibition held in conjunction with the conference will cover all software products, services and equipment related to engineering software. Con- tact Dr R Adey, Engsoft, 6 Cranbury PI, Southampton S02 0LG, ENGLAND. September 4-7 Compcon Fall '79, Capital Hilton Hotel, Washington DC. This 18th Institute of Electronic and Electrical Engineers (IEEE) Computer Society International con- ference will present the latest developments in micropro- cessor architecture, support software, operating systems, and peripheral devices. Con- tact IEEE Computer Society, POB 639, Silver Spring MD 20901. September 5-8 Info/Asia, Ryutsu Center, Tokyo. This exposition will be devoted to information management, computers, word processing, and ad- vanced business equipment. The exposition will be ac- companied by a 4 day con- ference. Contact Clapp and Poliak Inc, 245 Park Ave, New York NY 10017. September 8 2nd Annual Microcomputer Faire, Cullen College of Engineering, University of Houston. 70 exhibitors are expected at this computer fair. Contact Dr John L Hubisz, Division Natural Science and Math, College of the Mainland, Texas City TX 77590. September 12-13 Gateway Computer and Office Systems Expo, Chase- Park Plaza Hotel, St Louis MO. This 2 day event will include a program of ex- hibits and conferences which will be open to data proces- ing and business profession- als. Contact The Conference Co, 60 Austin St, Newton MA 02160. September 18-20 Wescon/79, St Francis Hotel, San Francisco CA. Contact Electronic Conven- tions Inc, 999 N Sepulveda Blvd, El Segundo CA 90245. September 24-26 Minicomputers and Distributed Processing, New York NY. This 3 day seminar will examine the uses, economics, programm- ing and implementation of mini computers. Contact The University of Chicago, Center for Continuing Education, 1307 60th St, Chicago IL 60637. 176 September 1979 © BYTE Publications Inc Circle 84 on inquiry card. September 25 DP User Documentation Workshop, Kansas City MO. The workshop will focus on how to write DP user manuals. Emphasis is on analysis of specific user needs; planning and outlin- ing; and effective writing, illustration and packaging of documentation. Contact Progressive Communications Inc, The Alamo/310, 128 S Tejon St, Colorado Springs CO 80903. September 25-27 Mini/Micro Conference and Exposition, Convention Center, Anaheim CA. Con- tact Robert D Rankin, Managing Director, Mini/- Micro Conference and Ex- position, 5528 E La Palma Ave, Suite 1A, Anaheim CA 92807. September 25-27 WPOE '79, San Jose Con- venter Center, San Jose CA. This show will be dedicated to word processing and office/business equipment, services and materials. Com- plementing the exhibit will be a 3 day executive con- ference program that focuses on emerging technologies and their applications in the office. Contact Cartlidge and Associates Inc, 491 Macara Ave, Suite 1014, Sunnyvale CA 94086. September 25-28 The 3rd Annual Data Entry Management Conference, Hyatt Regency, New Orleans LA. This conference will feature a full schedule of speakers, workshops, panels and vendor exhibits to assist the data entry pro- fessional. Contact Data En- try Management Associa- tion, POB 3231, Stamford CT 06905. September 26-29 MIMI '79, Queen Elizabeth Hotel, Montreal, Canada. This symposium is intended as a forum for the presen- tation and discussion of re- cent advances in mini and microcomputers and their applications. Special em- phasis will be given to the theme of the conference "The Evolving Role of Minis and Micros Within Distributed Processing." Contact The Secretary, MIMI '79 Montreal, POB 2481, Anaheim CA 92804. September 28-30 Northeast Personal and Business Computer Show, Hynes Auditorium, Boston MA. Displays and exhibits will showcase microcom- puters and small computer systems of interest to businesspeople, hobbyists, professionals, etc. Lectures and seminars will be pre- sented for all categories and levels of enthusiasts, in- cluding introductory classes for novices. Contact North- east Exposition, POB 678, Brookline MA 02197. OCTOBER 1979 October 1-3 2nd Annual Symposium on Small Systems, Hilton Inn, Dallas TX. The symposium will consist of a blend of paper and panel discussions with major emphasis on microcomputer applications. Both hardware and software topics presenting state-of- the-art and state-of-the- industry aspects will be in- cluded. Contact Gerald Kane, Southern Methodist University, Dallas TX 75222. October 2-4 NEPCON Central '79, O'Hare Exposition Center, Rosemont IL. This 10th annual exhibition and con- ference of electronic and microelectronic packaging and production equipment will feature displays of elec- tronic and microelectronic materials, hardware, tools, supplies and test instru- ments. Contact Industrial and Scientific Conference Management Inc, 222 W Adams St, Chicago IL 60606. October 14-17 International Data Proces- sing Conference and Circle 87 on inquiry card. CY-480 UPC™: THE WORLD'S ONLY SINGLE CHIP LSI UNIVERSAL PRINTER CONTROLLER. NOW ONLY $25.00! The CY-480 UPC" . others don't! . providing the kind of service and special features And that means for off-the-shelf low prices, the CY-480 provides great flexibility and easy interfacing. Cybernetic Micro Systems' amazing CY-480 will control and interface standard 5" x 7" dot matrix printers (including those from Victor, LRC, Practical Automation and Amperex) with speeds up to 200 CPS! Operating from a single +5V power supply, the flexible CY-480 will interface easily with any microcomputer or minicomputer system through standard 8-bit ports. The CY-480 accepts either serial (RS232C) or parallel ASCII input from the host system's data channel. The CY-480 replaces bulky, expensive, dedicated controllers. This small, single LSI package offers a 5 x 7 dot matrix character generator, full upper and lower case ASCII 96-character font, and a 48-character (expandable by daisy-chaining) internal line buffer storage. Standard features include a 10, 12 or 16 characters/inch variable character density command, and horizontal and vertical independently expanded print command. The CY-480 provides graphic capability and includes a "flip-print" operating mode for 180° viewing, and ready lines provide full asynchronous communications with handshaking. Stock delivery . . . only $25 a single unit . . . send for YOURS today! CYBERNETIC MICRO SYSTEMS 2378-B Walsh Ave., Santa Clara, CA 95050 Phone (408) 249-9255. VISA and MASTER CHARGE accepted. From S-lOO to IEEE-488 P&T-488+ S-100 computer = Intelligence for your Instrumentation System The P&T-488 permits an S-100 computer to operate as a talker, listener, or controller on the IEEE-488 instrumentation bus for less than half the cost of calculator-based systems. Software packages which give access to the 488 bus from high level lan- guages such as BASIC are available for CP/M, North Star DOS /BASIC, and Cromemco CDOS. Or "roll your own" system with the custom system package of assembly language drivers. P&T-488, assembled and tested, + any software package: $400 (domestic USA) Tro# PICKLES & TROUT P.O. BOX 1206, GOLETA, CA 93017. (805) 967-9563 Circle 308 on inquiry card. September 1979 © BYTE Publications Inc 177 Circle 288 on inquiry card. ■ I OAE'S new PP-2708/16 PROM Programmer is the only programmer with all these features: • Converts a PROM memory socket to a table top pro- grammer: No complex inter- facing to wire — just plug it into a 2708 memory socket* • A short subroutine sends data over the address lines to program the PROM • Programs 2 PROMS for less than the cost of a personal- ity module. (2708s and TMS 2716s) • Connect 2 or more in paral- lel — super for production programming • Complete with DC to DC switching invertor and 10 ^*Pat s Pending turn cermet trimmers (for precision pulse width and amplitude alignment) • All packaged in a handsome aluminum case PP-2708/16 . .A & T$325. PP-2716 (Programs Intel's 2716) A & T $295. OAE Oliver Advanced Engineering, Inc. 676 West Wilson Avenue Glendale, Calif. 91203 (213) 240-0080 Main/Frames . $2 •-»•..•.• Main/Frames „« m $200 ' 14 Basic Models Available ' Assembled & Tested 1 Power Supply: 8v@15A, ± 16v@3A • 15 Slot Motherboard (connectors optional) • Card cage & guides » Fan, line cord, fuse, power & reset switches, EMI filter » 8v@30A, ± 16v@10A option on some mod Rack mounted from $200 8" Floppy Main/Frame (includes power for drives and mainframe) from $365 Write or call for our brochure which includes our application note: 'Building Cheap Computers' INTEGRAND 8474 Ave. 296 • Visalia, CA 93277 • (209) 733-9288 We accept BankAmericard/Vlsa and MasterCharge Business Exposition, Town and Country Hotel, San Diego CA. Contact Data Processing Management Association, 505 Busse Highway, Park Ridge IL 60068. October 15-18 6th Information Manage- ment Exposition and Con- ference, New York Coli- seum, New York NY. Con- tact Clapp and Poliak Inc, 245 Park Ave, New York NY 10017. October 15-19 CPEUG 79, San Diego CA. This is the 15th meeting of the Computer Performance Evaluation Users Group sponsored by the National Bureau of Standards. Con- tact Judith G Abilock, The MITRE Corp, Metrek Div, 1820 Dolley Madison Blvd, McLean VA 22102. October 16-18 Understanding and Using Computer Graphics, Wash- ington DC. This course is for people who are now using, or making decisions about using computer graphics and its role in their organization. It will describe computer graphics, explain what hard- ware and software systems are available and give cost and performance com- parisons. Contact Frost and Sullivan, 106 Fulton St, New York NY 10038. October 20-21 4th Annual Tidewater Hamfest-Computer Show- Flea Market, Cultural and Convention Center, Norfolk VA. Contact TRC, POB 7101, Portsmouth VA 23707. October 21-23 New York State Association for Educational Data Systems Annual Conference, Granit Hotel, Kerhonksen NY. The theme of this con- ference is "Instructional Computing - Hardware/- Sof t ware /Courseware . " Contact Mary E Heagney, 9201 Shore Rd, Brooklyn NY 11209. October 22-24 The Association of Com- puter Programmers and Analysts 9th Annual Con- ference, Washington DC. The general theme of this conference is "Preparing Today for Tomorrow's New Technologies." Suppliers of software packages and com- puter services have been in- vited to describe and present their products in a series of structured presentations. Other sessions will cover trends in system technology and new methodologies for sharpening the professional skills of both systems analysts and programmers. Contact DBD Systems Inc, 1500 N Beauregard St, Alex- andria VA 22311. October 22-24 Computers in Aerospace Conference II, Hyatt House Hotel, Los Angeles CA. The conference theme, "Com- puter Technology for Space and Aeronautical Systems in the 80s," will be carried out by a series of panels, invited presentations, and con- tributed papers which will bring computer system technologists together with specialists in the application of embedded computers in space and aeronautics. Con- tact American Institute of Aeronautics and Astro- nautics, 1290 Ave of the Americas, New York NY 10019. October 22-25 ISA/79, O'Hare Exposition Center, Chicago IL. The conference theme, "Instru- mentation for Energy Alter- natives," will emphasize cur- rent practices in instrumen- tation design and implemen- tation. Contact Instrument Society of America, 400 Stanwix St, Pittsburgh PA 15222. October 22-26 Pascal Programming for Mini and Microcomputers, Ramada Inn, Woburn MA. Sponsored by the Polytechnic Institute of New York and the Institute for Advanced Professional Studies, this workshop will 178 September 1979 © BYTE Publications Inc Circle 177 on inquiry card. Circle 303 on inquiry card. include application ex- amples, lectures, informal sessions with the instructor, as well as individual and group programming ses- sions. Contact Professor Donald D French, Institute for Advanced Professional Studies, One Gateway Ctr, Newton MA 02158. October 28-30 The 10th North American Computer Chess Champion- ship, Detroit Plaza, Detroit Michigan. Sponsored by the Association for Computing Machinery, this is a 4 round Swiss style tournament with the 1st 2 rounds to be played on October 28th (1 PM and 7:30 PM), the 3rd on October 29th (7:30 PM) and the final round on Tues- day, October 30th (7:30 PM). Contact Monroe Newborn, McGill Univer- sity, School of Computer Science, 805 Sherbrooke St W, Montreal PQ, CANADA H3A 2K6. NOVEMBER 1979 October 29 - November 2 Applied Interactive Com- puter Graphics, University of Maryland, College Park MD. This course is designed to cover the most important facets of graphics that are necessary to develop general graphic applications. Systems considerations are stressed, including con- figuration selection criteria and the pros and cons of off-the-shelf software. The most important factors and techniques are described for hardware, software and geometric modeling. Contact UCLA Extension, 10995 Le Conte Ave, Los Angeles CA 90024. October 30 - November 1 Interface West, Anaheim Convention Center, Anaheim CA. This 3rd annual West Coast small computer and office automation systems con- ference and exposition will feature over 100 company exhibits and 60 conference sessions covering a variety of data processing, word processing, data communica- tions, mangement hardware, software and service topics. Contact the Interface Group, 160 Speen St, Fram- ingham MA 01701. November 5-8 Electronics Production Engineering Show, Kosami Exhibition Center, Seoul Korea. This international in- dustrial exposition will be devoted to the needs of manufacturers of electronic products in Korea. Contact Expoconsul, Clapp and Poliak International Sales Div, 420 Lexington Ave, New York NY 10017. November 6-8 Midcon/79 Show and Con- vention. O'Hare Exposition Center and Hyatt Regency O'Hare, Chicago IL. Contact Electronic Conventions Inc, 999 N Sepulveda Blvd, El Segundo CA 90245. November 6-8 Institute of Electronic and Electrical Engineers (IEEE) 3rd International Conference on Computer Software and Applications, The Palmer House, Chicago IL. Contact IEEE Computer Society, POB 639, Silver Spring MD 20901. November 6-8 3rs Digital Avionics Systems Conference, Fort Worth TX. This conference will probe the expectations and challenges of the digital revolution in avionics systems. Contact John C Ruth, Technical Program Chairman, POB 12628, Fort Worth TX 76116. November 12-14 Computer Cryptography, The George Washington University, Washington DC. The objective of this course is to provide each partici- pant with a working knowledge of the use of cryptography in computer applications. Contact Continuing Education, George Washington Univer- sity, Washington DC 20052. ■ nrartinol HppUbUUUIIU BOOT- STRAP TURN ON YOUR TRS-80 DISK SYSTEM AND GO RIGHT INTO YOUR BASIC PROGRAM— YOUR TRS-80 WILL LOAD AND RUN PROGRAMS— BY ITSELF! Yes, with this unbelievable program your computer will take command of itself whenever power-on or reset is pressed. Go from DOS all the way into your Basic program, execute DOS or Basic commands, load and execute any machine-language programs or subroutines you need (such as printer drivers, machine language sorts, etc.), set your file buffers and memory size, then run any Basic pro- gram you want, without lifting another finger! BOOTSTRAP'S custom files make turn-key end-user applications simple! Requires disk system, works with DOS 2.1, 2.2 and NEVVDOS, completely docu- mented for easy implementation. $15.95 PRACTICAL APPLICATIONS™ (415) 592 -6633 1313 Laurel St., Suite 15, San Carlos, CA 94070 □ Please send me TRS-80 BOOTSTRAP ($15.95 each enclosed. Calif, residents add tax). □ Send your catalogs. Name Address. City. is a trademark of Tandy Corp. State. -Zip. IOMMICOMPUTER PRODUCTS^ S-1 00 • TRS-80 |Ol APPLE • PET ^ ADD-ONS SPEECH SYNTHESIZER Quality, intelligible natural sounding COMPUTALKER Speech Synthesizer, a proven superior product since 1 976, comes complete with Load'N'Go software, user documentation and source programs. CT-1 S-1 00 Bus Plug-In $495 CT-1T TRS-80 add on w/interconnecl to self contained enclosure 595 CT-1 A Apple add on w/interconnect to self contained enclosure 595 CT-1 P Pet add on w/interconnect to self contained enclosure 595 FLEXIBLE DISK DRIVES Quality single or dual headed single or multi-drive configurations. Interconnects to self contained enclosures. Load'N'Go software and cable interconnects available when required. ^,. „._, 35/40 TRACKS _ , _. . . Flip Sided Dual Sided 40F1 Single Drive $400 40D1 Single Drive $500 40F2 Two Drives $700 40D2 Two Drives $800 40F3 Three Drives $990 40D3 Three Drives $1090 ALL PRODUCTS Fully Warranted - Sold Direct - Shipped Direct from Stock. Please contact us for prompt, personal, professional service. DIAL (714) NO.1 OMNI (714)661-6664 32422 Alipaz St., San Juan Capistrano, CA 92675 ^/ Circle 293 on inquiry card. September 1979 © BYTE Publications Inc 179 THE ORIGINAL' • Personal C Computing Plan Now to attend the best Personal Computing show ever, Friday, Saturday, Sunday October 5 -6 -7th Philadelphia Civic Center Philadelphia, Pa. PC 79 ® Don't be confused — Other shows are copying us but they cannot equal us. We are the Original Personal Computing Show. Now in our Fourth Year. FEATURING: Major Exhibits from the Leading Companies • Personal Computing College with 80 Hours of Free Seminars by the Industry's Leading Speakers • Major Emphasis on Software Exhibits • 2nd Annual Computer Music Festival Bigger! Better! • Antique Computing Devices on Display • See All the Latest Hardware • Business Systems and Business Software For more information and a Free subscription to our "PERSONAL COMPUTING" newspaper, send your name and address to: PERSONAL COMPUTING 79 Rt. 1, Box 242 . Mays Landing, N.J. 08330 . 609/653-1188 Industry TRADE SHOW on October 4th For exhibiting information please call or write. 180 BYTE September 1979 "THE ORIGINAL" > Personal C Computing EXHIBIT DATES & TIMES REGISTRATION at the door includes admission to all seminars. ■ 3 days — October 5, 6, 7 $10.00 ■ Single day $5.00 DEALER DAY Thursday, October 4 also includes October 5, 6, 7 $15.00 For Dealers, Purchasing Agents, Industry- Reps, Industry Officials only. 2nd annual PERSONAL COMPUTER MUSIC FESTIVAL Saturday evening, October 6, 1979. Harrison Auditorium, Univ. of Pennsylvania, which is 1 block from the Philadelphia Civic Center. Doors open at 6:30 P.M. Featuring; Live demonstrations and perform- ances by leading computer musicians. A stereo record from last year's music festival will be on sale at the show. Daytime seminars and demonstrations at the Philadelphia Civic Center all day on Saturday, Oct. 6th, during the Personal Computing Show. 800 Tickets will be on sale Friday and Saturday from P.A.C.S. at The Philadelphia Civic Center during the Personal Computing show and at Harrison Auditorium. The Personal Computer Music Festival is spon- sored by the Philadelphia Area Computer Society. For more information contact them at: P.O. Box 1954, Philadelphia, PA 19105. FRIDAY OCTOBER 5 SATURDAY OCTOBER 6 SUNDAY OCTOBER 7 9 A.M. to 6 P.M. 9A.M.to6P.M. 10 A.M. to 5 P.M. HIT rEL Ar.rnMiwinnATinwR HILTON Single $46, Double $56 ■ 215-387-8333 HOLIDAY INN Single $40, Double $46 ■ 215-387-8000 Downtown PENN CENTER Single $36, Double $41 ■ 800-523-0909 BEN FRANKLIN Single $32 $39, Double $40-$47 ■ 215-922-8600 PC '78 PHOTOS BY MARJ KIRK Speaker, David Ahl, Creative Computing magazine REMEMBER: Monday, Oct. 8th, is Columbus Day, <^ which gives an extra day to travel home. BYTE September 1979 181 The AMSAT-GOLEM-80 Joe Kasser 11532 Stewart Ln Silver Spring MD 20904 The AMSAT-GOLEM-80 Micro- computer Project provides a means for a group or club to put together an S-100 bus microcomputer in a relatively inexpensive manner. It is a modular system of hardware and software that can be built as a stand- alone system or superimposed on an existing S-100 machine. It is designed to be expandable and affordable. Many people who belong to micro- computer clubs, or who are learning about microprocessors, would like to own a microcomputer. However, they may not want to make the initial in- vestment of $500 to $1500 for the basic hardware. The AMSAT- GOLEM-80 is designed to be built in stages, as finances allow. Each stage of the AMSAT-GOLEM-80 is func- tionally complete and can verify the performance of the next stage. It is capable of incorporating any S-100 card, contains a powerful debugging software package (AMS-80 version 5.7), and the I/O (input/output) in- terface handlers for your system. It is designed to be flexible and easily customized to fit your requirements. This is recommended as a group pro- ject for 3 reasons: 1) to take advan- tage of bulk discounts in the purchase of hardware; 2) knowledgeable indiv- iduals are available to help others; and 3) test equipment can be shared. The order of construction is log- ical. Sections can be built and used to check out subsequent sections. Thus, a sequence of construction could be to build the cabinet and front-panel power supply, motherboard, console I/O card, programmable read-only memory card, programmable mem- Photo 1: The AMSAT-GOLEM-80 prototype computer. ory card (1), and processor card. At this level the basic AMS-80 program can be executed. The order of con- struction can be varied depending on the individual constructor's preference. The group can also build separate parts, put them together to get 1 machine working, then have the members build their own parts at their own pace. This technique of construction may not be the cheapest in the long run, but it is in the short run. It also allows nearly instant results, since the machine is doing something almost as soon as construction is begun. This is psychologically important, consider- ing the amount of money involved. It is difficult to decide which system is the cheapest in the long run. Building a microcomputer can be an open- ended drain on your finances because you will probably keep adding new memory and I/O peripherals. System Basics — Hardware The hardware is standard S-100 bus circuit cards, but any Z80/8080 processor card, memory card, or I/O card may be used. Circuitry is avail- able for a hardware front panel. This operates by putting the processor in the "hold" state and then taking over control of the bus lines. Memory and I/O ports can be exercised and checked out. A single-step feature is offered, as is jump start or boot start to a software monitor program. Sev- eral unique circuits are available for amateur radio use (eg: satellite tracking). Software The AMSAT-GOLEM-80 project is designed for active experimenters. It is expected that some machine- language programming will be per- formed on each machine. Thus, a full and expandable operating debug or 182 September 1979 © BYTE Publications lnc monitor package is available. This program AMS-80 is a much improved and expanded version of AMS-80 which was first published in the September 1976 issue of BYTE. Apart from the usual memory and register examine/change features, it incor- porates direct I/O operations, a disassembler mode, and keyboard- interruptable console operations. A list of the commands is shown in table 1. All I/O drivers are contained within AMS-80, devices can be con- figured in software, and all I/O devices are accessed via a jump table. All utility routines used within the monitor are also available via jump tables, as shown in table 2. The hex- adecimal base address is F000 and the I/O driver section of the jump table is compatible with the Technical Design Laboratory's Z80 monitor. Also available is a floating-point math pack (Intel software library ver- sion relocated), a floating-point inter- preter; a macro-organized pseudo high-level language using a floating- point stack, and operating through the math pack and various other soft- ware, including radio teletypewriter (RTTY) reading programs which are mainly suited for amateur radio ap- plications. Patches for commercially available software (but not the actual software) are also available. These patches include Processor Tech- nology 5 K BASIC and North Star's disk operating system. The Power Supply The power supply is 1 of the 2 single-point failure points in the system (the other is the processor). If it fails, the system is down. Thus, it should be overrated, cooled, and have a little spare capacity on hand. It should be capable of at least the following performance: 8 to 10 V at 10 to 20 A, 16 to 18 V and —16 to —18 V at 2 A. The supply can be unregulated because each S-100 card carries voltage regulators as required. Use plenty of fuses; put 1 in the AC line and 1 in each of the DC supplies, as shown in figure 1. If you wish to add crowbar circuits, over-voltage protection, or shut-down circuits, that's fine. The Cabinet The cabinet is the part of the A B C D E F G H I I J K L M N P Q R S T U V w X Y z PRINT (MEMORY) IN ASCII * CONFIGURE I/O (INPUT/OUTPUT) DEVICE DISPLAY (MEMORY) IN HEXADECIMAL WRITE END OF FILE RECORD TO TAPE FILL (MEMORY) WITH CONSTANT GO TO LOCATION AND EXECUTE HEXADECIMAL MATH (SUM AND DIFFERENCES) NPUT FROM PORT TO CONSOLE PRINT (MEMORY) IN ASSEMBLY LANGUAGE MOVE BLOCK OF (MEMORY) PUNCH 6 INS LEADER TAPE OUTPUT TO PORT FROM CONSOLE SCAN TAPE * READ TAPE EXAMINE/CHANGE (MEMORY) PUT HEADER ON TAPE DISPLAY I/O CONFIGURATION VERIFY PROGRAMMABLE MEMORY BLOCK WORKS WRITE TO TAPE EXAMINE/CHANGE (REGISTERS) 'Not assigned as yet. Table 1: AMS-80 version command list, version 5.7. Details of the operation of the commands are given in the description of AMS-80. Interactive Computer Graphics Software* For Microsoft and DEC* Fortran DEVIATIONS ' J''i "'{( *^> t i,n!', to sncra ■ mentft ! n high speec Self-re.;'""" •'! raster scan displays The complete p '•. written in standard Fortran IV, making it porta- ble to all computers, including mini and mi- ms. The entire set of over 20 subpro- grams. >r a CRT ter- minal and a Diablo 1620 printer, sells for $4 ! ier devic may I *Tr JMP CUSTOM START OF SOFTWARE JMP CONSI CONSOLE TO JMP RDR READER TO JMP CONSO TO CONSOLE (ASCII) JMP PUNCH TO PUNCH (ASCII) JMP LIST TO LIST (ASCII) JMP CSTS TEST CONSOLE STATUS JMP IOCHK DETERMINE I/O (INPUT/OUTPUT) CONFIGURATION JMP IOSET SET I/O CONFIGURATION JMP MEMCK FIND TOP OF USER AREA (PROGRAMMABLE MEMORY) JMP RESTART BREAKPOINT ENTRY ENTRY POINTS JMP START REENTER BMS-80 JMP BEGIN BYPASS CUSTOMIZING AREA CONSOLE ROUTINES (INDIVIDUAL) JMP CHIN ; CONSOLE INPUT AND ECHO JMP CONSA ; TO CONSOLE JMP TCSTS ; GOTO MON IF CONSOLE INTRPT JMP TCRET ; OUTPUT CR/LF JMP AOUT TO CONSOLE JMP THXB OUTPUT (HEXADECIMAL-2 DIGITS) JMP THXW OUTPUT (HEXADECIMAL-4 DIGITS) JMP MSG OUTPUT TEXT JMP PCHK TEST FOR NULL INPUT CHAR JMP CONSB TO CONSOLE (ASCII) PUNCH ROUTINES JMP PHXB TO PUNCH (HEXADECIMAL) JMP LEAD PUNCH 6 INS LEADER TAPE JMP PCRET OUTPUT CR/LF TO PUNCH JMP PHXW OUTPUT H/L TO PUNCH JMP POB TO PUNCH (ASCII) LIST ROUTINES JMP LHXW OUTPUT H/L TO LIST JMP LHXB TO LIST (HEXADECIMAL) JMP LCRET OUTPUT CR/LF TO LIST JMP LOB TO LIST (ASCII) UTILITY ROUTINES JMP CONV CONVERT HEXADECIMAL TO ASCII JMP NIBBLE CONVERT ASCII TO HEXADECIMAL JMP DONE TEST FOR COMPLETION JMP TIMER DELAY JMP SDEHL HL-DE JMP LOCMB LOCATE CONTROL BYTE IN PROGRAMMABLE MEMORY BLOCK JMP IRST RESET INTERRUPTS JMP BACON BAUDOT TO ASCII CONVERSION JMP ASCBD ASCII TO BAUDOT CONVERSION JMP $ SPACE FOR PATCHES JMP $ Table 2: AMS-80 interface jump table. The individual routines are discussed in detail in the description of AMS-80. system that your friends will see and admire. It should look presentable. The number of switches and lights on the front panel has been the subject of numerous debates. Those which are necessary are a power on/off switch, a boot switch, and a reset switch. If you are doing a lot of I/O program- ming (common in amateur radio applications), an output port and an input port (sense switches) are useful. Status lights, control bus lights, and data and address bus lights/switches are optional. One full hardware tester panel should be built within each group if no known working system or other method for troubleshooting the hardware is available. The prototype shown in the photograph contains the full hardware tester panel circuit and is built separately from the power supply. This has the advantage of portability. The Front Panel Interface This card interfaces the front panel switches and displays to the S-100 bus. It is used when first building the system to check out the operation of the individual cards. Once AMS-80 is running, its usefulness is diminished until a hardware failure occurs that leaves the system up, but inhibits the processor from working properly (eg: a bus buffer or data-bit failing). The controls on the front panel will then 184 September 1979 © BYTE Publications Inc Ihe Data Duo* FromDTC &* w rifi N? 0" MS* > 6 > <$r .A®" *V» «^ ^' I ■ ^— ^W i^^' ^m *T Sw^WrTSPTBFw*^W"^** USE "Pf* t*% '^n '^"^RtlSK'" iSK'^lfc'' wK '^Bfc iK ^mims*^^. > ijj^efiTOB&nagn ',^^ygs»ggt v. 10-12 VAC RECTIFIER Fl 20A -of"Vx, L> ; 100,000^ f ) +BV -o RECTIFIER F2 2A — oi w o> CO 7— o o o m M c o (0 en O -* — (0 Q.NJ < 2 en -a o 2 w tr it o o x> o o o 0) CO II O CO W ca a> « d cr d 0) ra — a> C co — CD i- -t O co --■ <" 5 a> o u ~ 2=5 o. a) 2 ? «<5 o o n o o o o cd ■o a n a co a. ca co o £ "J O c CD o £ a o o JO J*. o o o <5 g 1-3 SI o o d CM ■ 6 <2 § «>£ g." 8 E 2 P O co o o in o o o o m lo CM d in en d o in cd o o CO CO a « 9 5 "o *■ c ii o 2? 3 = ■o ~ So c> o o o o o % k- "is 5 3 O o .net — o O co s^ s s •— 5 a> x a a a a a a a In o o 3 ■o c e o to S * a a. D o o oo CO a ■a 0) £ in o o ca CO a (A U c o o in co" O 4! £ eg co CD O g "55 £ o 2 o o QQ CO Q a> ■o o ■a c 03 __. i- ■*-• a co H <= co — •— CO (0 CO C x CO CD d a a BITS™ Brings Vou the B€ST CH€CK THIS OUT > ^Qk> IT ^H [then check m them off!] (A E c o d u < c o u ">< cd 0) n _l >< L. CO a (A 8.2 ll o in oi CM c 'Jo 0J a E a> ■•- u> >. "- o | co J? a> .£ 2 5 Q.UJ ei w o> O 1- O 8 5 o 5 o LO o o in in d o> CO CD 5 9 o h~ Tt CO » c CD c a E o O o m m CM h» t- m o co"? ~ CO 3 M O «• — LO o o ° oB S O) c Eo ll CO < 1 1* < ■o — CO >- o S c> CO — o3 CD O CD 1- c °- o O -Q O co CO O CO CD = O C co ECO Is 0- O °P o N CD c 18 M CO < O CD h- C °- o O -Q oo co O O CO o Q St ■3 S E CO O x o ^ u ^ s8 i- 03 « CO P 00 c _o a> ■o c CM ^" o o 00 CD E c a> to Q.S E-co 3 ca (/) x o o 00 c o co 2 coir ** — *s « Q « Q -o rJ cd -J c I- I- I- CM C 'S CD • Q ^ CO c E » CD CO Cfl E§ ca 03 "- « a> Q o O ■o CD CD CD CD co C c CD co 1 » a ^ co co C CD o ^ ■^ _l 03 -^ o o ~ CO a. Q. 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R) o ? o oo CO £ E cl) c I < oct d CO CD CL CL CO 2P ± o n a n a a □ a d □ □ a a a a a a BYTE September 1979 191 Circle 54 on inquiry card. Control System Software lection of software for anafyzin trol systems. The set includ« quency domain methods such as Bode and Root Locus algorithms, and modern start* variable methods. These programs will calculate the data for a given system, and then pro- duce a tabulated printed output, a graphical display on a printer, or both The programs include both the analy- sis subprograms and the printer plot- ter subprogram. • Bode Algorithm CS-B $100. • Root Locus Algorithm CS-R $100. • Time Response ..... .CS T $100. All of the above packages will run on a 8080 or Z80f — based CP/M* system. ^Trademark of ZHog trademark of CHgttal Research COMPCO is a software and hardware systems development house located In the Midwest. COMPCO has a variety of software products, and performs custom and contract programming. COMPCO is a distributor of ALTi Computer systems and also sells General Robotics LSI-11* systems ^Trademark of Digital Equipment Corp. wompco 8705 North Port Washington Road Milwaukee, Wis. 53217 414/351-3404 COMPUTER SPECIALISTS Punch P = 3 P = 2 P=1 Audio Cassette P = Console Reader R = 3 R = 2 R=1 Audio Cassette R = Console List L = 3 L = 2 Baudot device (model 15) L=1 Teletype Port L = Console Console C = 3 C = 2 Baudot Device (model 15) C=1 Video Display Board/Keyboard c = o Teletype Port Video Di; >play Board V = Page With Line Foldover V=1 Page Without Line Foldover V = 2 Scroll With Line Foldover V = 3 Scroll Without Line Foldover Table 6: AMS-80 I/O (input/output) allocations. comprises 4 K bytes of programmable read-only memory of user memory, and a terminal device. With this amount of hardware, you can run AMS-80, enter programs in memory in hexadecimal code via AMS-80, and learn a little about software. The ad- dition of some off-line memory, such as audio or paper-tape devices, allows you to run programs which re- quire up to 4 K bytes of memory. Such programs include Tiny BASIC, orbital calculations for amateur satellite locations, and various amateur radio programs. If you have a radio teletypewriter terminal unit (RTTY-TU), you can even tune your shortwave radio in to commercial or amateur Teletype stations, and display their transmissions on your terminal. If you get a modem interface and a second terminal, or use a video display/keyboard combination and a serial port/modem, you can make the basic system into a remote terminal for a large machine timesharing ser- vice, and access the computer at work from your home. Add another 4 or 8 K bytes of user memory, and you can run text editors, assemblers, or an 8 K BASIC interpreter. This opens a new dimension in computing. You can play Star Trek, and run education and business software and advanced amateur radio programs, such as con- tests. Put 16 K bytes of user memory in your system and you can get a floppy disk unit for an added dimen- sion in computing. Off-Line Data Storage Off-line storage is storage for pro- grams and data that is external to the 64 K bytes of accessible memory. It usually consists of audio tape, floppy disks, or paper tape. Floppy disk storage usually comes with an operating system and will not be discussed here. AMS-80 contains 192 September 1979 Bowling Bookkeeper prompts the user 6 even a hon^omputerlte -dtii easily use th The Bowling Bookkeeper ; runs under standard CP/M* The entire Bowling Bookkeeper-!- system which includes a start \ t- £.^ up program, a score entering program, a posting program, and an \ _ ^f.. : error recovery program costs $400. A complete computer system \ consisting of an Altos 8000-1 microcomputer, a Mierpterm MIME terminal, CP/M* operating system, and the Bowling Bookkeepe available from CQMPCO for under $5,000. i trademark of COMKO •trademark of Digital Research $400 for Complete Package \ Compco COMPUTER SPECIALISTS 705 North Port Washington Road Mi Circle 55 on inquiry card. September 1979 © BYTE Publications Inc 195 Add Some Control to Your Computer An Output Port Tutorial Ken Barbier POB 1042 Socorro NM 87801 A virtually limitless number of devices can be controlled through a single output port using time multi- plexing techniques. A series of 8-bit bytes is fetched from a control buffer in memory, and output through a single port. On the receiving end, bus buffers present the data to all the devices in parallel, but unique strobes are supplied to each device in turn, so that it can latch its own data word. This technique is particularly useful if the devices are to be located some distance from the computer. DS»0 The hardware shown in figure 1 has been used to control devices over 50 feet from the computer without exotic line drivers and receivers. Since remote addresses for each device are generated by the hardware, only 8 data lines and 1 strobe line are re- quired. For maximum noise immu- nity, shielded twisted pair cable should be used. Receive Hardware In figure 1, 16 external devices receive 1 8-bit byte apiece. Using the Intel 8080, this block of data will be transmitted in about 300 „S. The I/0(input/output) write strobe accompanying the 1st byte triggers a delay oneshot which, after allowing more than enough time for the block transmission, triggers a reset oneshot which clears the remote address counter, the 74160. This insures that the next block of data will be routed to the correct device in turn. The remote address counter sup- plies a 4-bit count to the 4-line-to-16- line data selector, the 74154. As the TYPICAL OF EIGHT »o IOWC-ADRs| ^> Number Type + 5V Gn IC1 7406 14 7 IC2 7404 14 7 IC3 74123 SEE FIGURE IC4 74160 16 8 IC5 74154 24 12 Figure 1: The transmission circuitry is divided into 2 parts, the data transmission (DO through D7) and the address. The address is decoded by a counter which determines which 1 of 16 devices is being used. The write strobe accompanying the data triggers a delay oneshot (IC3a) which triggers a reset oneshot (IC3b) which clears IC5, the remote address counter. 196 September 1979 © BYTE Publications Inc RADIO SHACK COMPUTER OWNERS TRS-80 MODEL I AND MODEL II TRS80 MONTHLY NEWSLETTER • PRACTICAL APPLICATIONS • BUSINESS • GAMBLING • GAMES • EDUCATION • PERSONAL FINANCE • BEGINNER'S CORNER • NEW PRODUCTS • SOFTWARE EXCHANGE • MARKET PLACE • QUESTIONS AND ANSWERS • PROGRAM PRINTOUTS AND MORE PROGRAMS AND ARTICLES PUBLISHED IN OUR FIRST 12 ISSUES INCLUDE THE FOLLOWING: A COMPLETE INCOME TAX PROGRAM (LONG AND SHORT FORM) INVENTORY CONTROL STOCK MARKET ANALYSIS WORD PROCESSING PROGRAM (FOR DISK OR CASSETTE) LOWER CASE MODIFICATION FOR YOUR VIDEO MONITOR OR PRINTER PAYROLL (FEDERAL TAX WITHHOLDING PROGRAM) EXTEND 16-DIGIT ACCURACY TO TRS-80 FUNCTIONS (SUCH AS SQUARE ROOTS AND TRIGONOMETRIC FUNCTIONS) NEW DISK DRIVES FOR YOUR TRS-80 PRINTER OPTIONS AVAILABLE FOR YOUR TRS-80 A HORSE SELECTION SYSTEM***ARITHMETIC TEACHER COMPLETE MAILING LIST PROGRAMS (BOTH FOR DISK OR CASSETTE SEQUENTIAL AND RANDOM ACCESS) RANDOM SAMPLING***BAR GRAPH CHECKBOOK MAINTENANCE PROGRAM LEVEL II UPDATES***LEVEL II INDEX CREDIT CARD INFORMATION STORAGE FILE BEGINNER'S GUIDE TO MACHINE LANGUAGE AND ASSEMBLY LANGUAGE LINE RENUMBERING AND CASSETTE TIPS, PROGRAM HINTS, LATEST PRODUCTS COMING SOON (GENERAL LEDGER, ACCOUNTS PAYABLE AND RECEIVABLE, FORTRAN -80, FINANCIAL APPLICATIONS PACKAGE, PROGRAMS FOR HOMEOWNERS, MERGE TWO PROGRAMS, STATISTICAL AND MATHEMATICAL PROGRAMS (BOTH ELEMENTARY AND ADVANCED) . . . AND ftttt WORD PROCESSING PROGRAM (Cassette or Disk) For writing letters, text, mailing lists, etc., with each new subscriptions or renewal. LEVEL II RAM TEST - Checks random access memory to ensure that all memory locations are working properly. SEND FOR OUR 36 PAGE SOFTWARE CATALOG (INCLUDING LISTINGS OF HUNDREDS OF TRS-80 PROGRAMS AVAILABLE ON CASSETTE AND DISKETTE), $2,00 OR FREE WITH EACH SUBSCRIPTION OR SAMPLE ISSUE. CQMPJTRaNICS fvA&TV^^ATCAL APR.CATCT-JS Box 149 New City, New York 10956 ONE YEAR SUBSCRIPTION $24 TWO YEAR SUBSCRIPTION $48 SAMPLE OF LATEST ISSUE $ 4 START MY SUBSCRIPTION WITH ISSUE _ HOUR 24 ORDER LINE (914) 425-1535 (#1 - July 1978 • #7 - January 1979 • #12 - June 1979) NEW SUBSCRIPTION RENEW AI CREDIT CARD NUMBER SIGNATURE EXP. DATE . NAME ADDRESS ADD S6/YEAR (CANADA, MEXICO) - ADD S12/YEAR AIR MAIL - OUTSIDE OF U.S.A., CANADA & MEXICO ' Circle 159 on inquiry card. BYTE September 1979 197 74160 advances its count on the rising edge of its clock, it will initially supply address to the 74154 until the trailing edge of the negative going I/O write strobe. This same strobe is the "data" supplied to the 74154, and so will appear on each of the outputs of the 74154 in turn. This constitutes the 16 remote addresses. For expansion, 1 additional counter stage could be used to generate "first 16" and "second 16" control signals to double the number of devices. Driver Programs The example shown in figure 1 is for 16 devices. Every time we want to output a control to any one device, we must output all the control words. OUCNT is an 8080 routine designed to accomplish this (see listing 1). The calling program first loads the correct bit patterns into the correct buffer words, then sets the flag at memory location FLAG. This flag is used to prevent needless outputting of the controls. In a complex control pro- gram, many segments of the oper- ating system may need to change the state of the devices at irregular inter- vals. In such an implementation there will be a fixed program cycle, with many tasks called in turn to perform their functions. At some point in the cycle, time will be allotted to output our controls. If no program segments or tasks have called for any change in the controls, it is not necessary to transmit them, and the flag will not be set. But when it is set, we will transmit all the controls, after clear- ing the flag. Controlling Relays Typical applications for this tech- nique might include driving remote displays, with 32 -decimal digits being transmitted, 2 per 8-bit byte. Or, as is shown in figure 2, 8 relays can be controlled by each 8-bit byte. The simplified schematic of figure 2 shows a relay driver circuit capable of controlling 8 relays. The 8 bits of data are latched into the 74175s on the ris- ing edge of the clock, so our negative going strobe can be used as is. If lat- ches such as the earlier 7475 are used, the strobe would have to be inverted, since the output of a 7475 follows the input whenever the clock is high. In either case, any relay whose corres- ponding bit is not changed will re- main in the previous state, as its cor- ;OUTPUT CONTROLS CONTR EQU OUCNT: LDA AN I RZ MVI STA LXI MVI OUCN1: MOV OUT INX DCR JNZ RET FLAG: DB BUFFER: DS OUTPUT PORT ADDRESS FLAG ;NEED ACTION? OFFH ;NO, RETURN A,00 ;YES, CLEAR FLAG FLAG H.BUFFR ;GET CONTROL BUFFER ADDRESS O0FH ;SET COUNTER A,M ;GET CONTROL DATA BYTE CONTR H INCREMENT ADDRESS C ;DECREMENT COUNTER OUCN1 ;CONTINUE IF NOT DONE ;ELSE, RETURN ;ACTION FLAG OFH ;CONTROL BUFFER Listing 1: 8080 assembler routine to output control signals to 1 of 16 devices. CONTR is equated with the desired output port address. responding latch is reloaded with the same data as before. (The type of NPN driver transistor will have to be selected to match the current and voltage requirements of the particular relay used.) Relay Control Program Obviously, if we need to control 8 relays with 1 byte, we do not want to change the state of all of the relays at the same time. This complicates the software required slightly. In the 8080 program shown in listing 2, a change relay subroutine allows us to change the state of 1 relay at a time. We must supply the subroutine with the number (hexadecimal thru F) of the word in the buffer corresponding to the relay driver board, and a relay number (1 thru 8). We must also specify whether we want to turn it on or off. At the correct time, we put the word number in register C, the relay number in register E, and set register A to 1 for on, or for off, and call CHGRY. The next time the operating system calls OUCNT, only our + 5V D0 Q> 74175 CLOCK 2Q 3Q 4Q D6 O- 13 ■o 10 •o m ID 2D 3D 4D CLOCK 74175 IQ 2Q 3Q 4Q ■o ■o ■o 15 ■o Figure 2: A relay driver board capable of controlling 8 relays. The state of the relay, on or off, is latched into the 74175 until a following strobe is received directing a change in state. 198 September 1979 © BYTE Publications Inc For rush or credit card orders, call 1415) 548-2805 SI 050 Circle 292 on inquiry card. BYTE September 1979 199 "^ exclusively from BITS inc. TRS-80* Software FREE with this Definitive Text! ?i *** 18 chapters of solid, accurate programming information: • Debugging techniques • Interrupt modes • Array and table handling • Number base conversion • Floating point arithmetic • Programmed input/output • Stack pointer usage The last part of the book is soft- ware, an editor /assembler which will run on any 8080 or Z80 ma- chine and a debugging monitor. Send in the coupon supplied with the book and receive FREE the object programs of the editor/ assembler and debug on either paper tape or on cassette tape for the TRS-80 microcomputer. (Loads in Level I with 16KRAM or Level II.) Both the book and software for only $29.95! G Practical Microcomputer Pro- gramming: The Z80 by W J Weller For North Star Disk Systems: Now available for the Z80 on Single Density diskettes □ Editor/assembler object code $14.00 □ Editor/assembler and debug source code $14.00 D both for only $26.00! (Postage $.75/ item or $1.00 outside U.S.) * A trademark of Tandy Corp. DIAL YOUR BANK CARD ORDERS TOLL FREE 800-258- 5477 1 (In N.H. dial 924-3355) i^SP : rarv or enclose your check with this ad: Name Address Zip 1B1099 ISII dine Books to erase the impossible POB 428. 25 Roole 101 West. Peterborough NH 03458 Ask for our new, FREE Catalog CHANGE RELAY ENTER WITH: CONTROL WORD NUMBER IN (C) RELAY NUMBER IN (E) (A) = 1 TO TURN RELAY ON (A) = TO TURN RELAY OFF CHGRY: LXI H.BUFFR ;GET BUFFER START ADDRESS MVI B,0 ;ADD WORD NUMBER DAD B ANI 0FFH ;TURN ON OR OFF? JZ OFF CHGR1: DCR E TURN IT ON JZ CHGR2 ;SHIFTBITTO RELAY RLC ; POSITION JMP CHGR1 CHGR2: ORA M TURN THIS ONE ON MOV M,A CHGR3: MVI A.0FFH ;SET CONTROL FLAG STA FLAG RET ;AND RETURN OFF: MVI A.0FEH TURN RELAY OFF! OFF1: DCR E ;FORM MASK WORD JZ OFF2 ;SHIFT "HOLE" TO RLC ; RELAY POSITION JMP OFF1 OFF2: ANA M TURN THIS ONE OFF MOV M,A JMP CHGR3 ;AND RETURN Listing 2: This 8080 routine allows a state change for only 1 relay in a set of 8 instead of changing all relays at once. INITIALIZATION SUBROUTINE IN IT; MVI A,00 OUT CONTR MVI A.14H INIT1: LXI H.BUFFR MVI C0FH INIT2: MVI M,00 INX H DCR C JNZ INIT2 DCR A JNZ INIT1 CALL OUCNT RET ;CLEAR REMOTE ADDRESS ; COUNTER ;CLEAR BUFFER AND ; DELAY ROUTINE ;LOOPTIME IS 250 USEC ; SO DO IT 20 TIMES TO ALLOW RESET ; OF REMOTE ADDRESS, THEN OUTPUT ALL ZEROS ;AND RETURN Listing 3: Initialization routine to clear the address counter, buffer, and outputs all 0s to devices connected to system. selected relay will change state, even though all the controls are output. Error Free Operation To insure that all controls have been received correctly, some sort of feedback to the computer can be pro- vided. In actual practice this is usual- ly unnecessary, but if it must be implemented, there are several pos- sible techniques. First, 74180 parity generator and checkers could be used to generate a parity bit on the transmit end, and check it on the receive end, sending back an interrupt if any word re- ceived is in error. This would add only 2 more signal conductors to the 9 already in the cable. Additionally, at the end of the delay oneshot time (and before the reset occurs), the remote address counter can be tested to insure that it has reached the all Is state. A count error signal can be ORed with the parity error signal to produce a single interrupt in case either error should occur. The oper- ating system can then try the transmission again, or at least indi- cate its existence. System Initialization Since, upon initial application of power, the states of the latches and the 74160 counter will be indeter- minate, the initializing subroutine of listing 3 should be called at power on and reset times. This will clear the address counter, the buffer, and out- put all 0s to all devices. I hope this short discussion of out- put port techniques will help readers to understand how the computer can be interfaced to the real world. ■ 200 September 1979 © BYTE Publications Inc Expansive but not expensive MicroAge introduces for Horizon and Alpha Micro Systems, the most powerful Hard Disk Units You've Ever Seen. Welcome to "Hard" Times: a new age of hard disk cartridge drives for Horizon and Alpha Micro . . . so powerful, so reliable, so economical, you've never seen anything like it. Fast, easy and versatile: the revolutionary new Fujitsu M2201 with 40 (formatted) megabytes of storage . . . and the dynamic CDC Phoenix with 27 (formatted) megabytes. Both are operated with North Star and Alpha Micro commands. Added capacity means the ability to fully utilize the complete range of software and capabilities of North Star Horizon and Alpha Micro mainframes. But their family interface compatibility is not all that's expansive. Speed and economy are impressive, too. Super-fast access time means no waiting for command execution . . . easy handling of large files. And the price? Unbelievably low for this much flexibility, power, speed and capacity. And the low price includes the hard disk drive, S-100 controller, software interface, cords and disk pack. Fujitsu M2201 Cartridge Module Drive 50 megabyte storage (40 formatted) Exclusively from MicroAge CDC Phoenix Cartridge Module Drive 32 megabyte storage (27 formatted) Either. $9995.00 Includes drive, S-100 controller, software interface and disk pack. Ask your dealer about Hard Times — the Fujitsu M2201 and CDC Phoenix drives from MicroAge. Available to qualified dealers and OEM's. If a dealer is not available in your area, call 800-528-1415. Circle 212 on inquiry card. BYTE September 1979 201 Text continued from page 6: The scope of the new homebrew design has now expanded to include relatively high-speed serial RS-232C communications among the homebrew node, the Western Digital P-engine, the Able/60-Synclavier, and other computers from time to time. I intend to use RS- 232C at 19.2 K bps as the communications discipline, primarily for its universality. Today one can get almost any computer with a standard 25-pin D connector set up for the RS-232C discipline, at speeds ranging from a lethargic 110 bps to a maximum of 19.2 K bps. This upper-limit of speed is not exceptionally fast (about 1800 bytes per second is the equivalent in a useful mea- sure), but the existence of these standard signal levels and standard connectors argues for this kind of approach. The diagram of figure 1 shows how the overall concep- tion of the system stands at present. The homebrew 6809 simultaneously provides a facility to directly execute Figure 1: How the 6809 homebrew computer fits into a bigger system. The new 6809 computer will serve as a central com- munications node for multiple computers involved in this per- sonal system. At present 2 complete computer systems are involved, with serial communications via the 6809 node, which is the subject of this homebrewing series. The Able/60 has several specialized peripherals which will be used for personal research purposes, such as, high-speed 16 channel analog-to- digital input conversion and a real-time clock with 1 fis reso- lution. In this diagram, mass storage equipment is not shown, but it is a part of each computer: the Able/60 computer includes 2 5-inch floppy drives, and 2 full-size floppy drives as its mass storage complement. The P-Engine machine includes 2 double density, standard-size floppy disk drives. 6809 code for experimental purposes, and a more per- manently useful function of a common communications node which can be the subject of various serial com- munications strategies relative to the other processors. Lest readers wonder, this is and remains a personal computer. It is true that the system is getting a bit large for one person to operate all of the terminal and music keyboards simultaneously, yet it resides in my home along with various other facilities of the complete com- puter experimenter: electronics shop, woodworking shop, and the beginnings of a machine shop. This expanded conception of function for the home- brew 6809 barely changes the hardware design details originally conceived. The computer will have 16 K bytes of memory to start, several terminal ports, several parallel ports, and space for 4 K bytes of ultraviolet, erasable read-only memory. The read-only memory will contain the implementation of low-level, communi- cations-monitor software and key parts of a reverse- polish notation, stack-oriented, threaded interpretive language. Remember that the conception of a homebrew or commercial system made of modular components can change considerably in detail as a result of time and resources available. As the system design develops from this initial inten- tion, its actual detail may prove inconsistent with what I have conjectured thus far. Recognizing this starting point, I invite readers to follow in on a guided tour of the current state of my thinking about this new, homebrew, microprocessor system project. Let's see how the central processor bus design comes out, what logic blocks will be required, and let's have some preliminary thoughts on the ORGAN MANUALS TO STEREO MANUAL AU0IO MIXING SYSTEM TO 16 MUSIC CHANNELS (PREMIXED TO STEREO) REAL TIME CLOCK ADC'S ■ 16 CHANNELS PARALLEL I/O SERIAL I/O SYNCLAVIER NEW ENGLAND DIGITAL WESTER DIGITAL •ENGINE MACHINE 0-8 MUSIC CHANNELS (PREMIXED TO STEREO) SPARE SERIAL CHANNELS RS-232C HOMEBREW 6B09 - COMMUNICATIONS NODE ALF PRODUCTS FUTURE COLOR GRAPHICS DISPLAY PROCESSOR MARANTZ-SUPERSCOPE "VORSETZER" STEINWAY PIANO OUTPUT 202 September 1979 © BYTE Publications lnc COME TO AST INESS HYNES AUDITORIUM, PRUDENTIAL CENTER, BOSTON Interested In Personal Computers? This is the place for you! You'll meet and talk with hundreds of manufacturers, distributors and retailers . . . all showcasing their new 1980 Micro, Mini and Small Computer Systems. You'll see them all. ..Radio Shack, Pet, RCA, Compucolor, Heathkit...you name it! All the major terminal and peripheral companies too, plus software developers magazine editors and book publishers. Yes, it'll be the largest showing of personal computer hardware, software and services ever assembled in the Northeast! You'll be enthralled, entertained and educated. You'll see computer art, graphics and animation. You'll hear computer synthesized music, watch computerized amusements, play electronic and video games wl and attend scores of free tech talks and briefings given by internationally recognized speakers. And you may win a free computer given away as a door prize! Don't miss the largest gathering of computers and computerists! No pre-registration necessary. Tickets available at the door. Adult admission $5.00. Produced by Northeast Expositions, P.O. Box Interested In Business Systems? Interested in Business Systems? This will be your one opportunity to see all of the Mini, Micro and Moderate Sized Computer Systems under one roof. Your attendance at this show is a must if you, or your company, are contemplating the purchase of any type of computer or office equipment. You'll see them all. ..the big ( and small) names in computers, data and word processing eqiupment, peripherals and software. You'll attend dozens of free, easily-understood briefings on how computers can help you in your business or profession. '* So if you're considering a computer or computer- related service. ..starting yourown computer business or changing your job within the mputer industry. ..or if you'd just like to learn more about computers as they relate to your personal life and to your business or profession, come to the show to see the Computerized World of Tomorrow. ..Today. And bring the entire family, It's a fun- filled educational experience. No pre-registration necessary. Tickets available at the door. Adult admission five dollars. lage, MA 02147 (617) 522-4467 Circle 284 on inquiry card. BYTE September 1979 203 Circle 401 on inquiry card. Z S - SYSTEMS 64K RAM BOARD The Z S -SYSTEMS 64K RAM board is designed to operate in any Z80 based microcom- puter having S-100 bus. It uses 16K dynamic RAM chips, & features: — Board select — Bank select — Transparent on-board refresh — 2 or 4MHz operation (w/ no wait state) — Memory disable FLOPPY DISK CONTROLLER Handles with no modification up to: * 4 standard 8" drives (Shugart or compatible) or * 3 minidrives 5" Run with 2 or 4 MHz CPU Compatible with Cromemco system, Fully assembled, burned in, & tested Available from stock to 60 days As low as $500.00 in quantities of 100 Price of one $649.00 PC board only $59.00 With 16K RAM $359.00 Plus shipping charges Use CP/M Disk Operating System Using the 1771 LSI controller Price oi one $245.00 SEND FOR FREE INFORMATION 6 months warranty on our boards with norma/ use Zs SYSTEMS PO Box 1847, San Diego, CA 92112 (714) 447-3997 16K STATIC RAM with $275 450 ns $300 250 ns memory chips Assembled, Tested and Guaranteed Static TMS 4044 or equivalent - Fully Static 4Kx1 Memory Chips for full DMA capability, no tricky timing problems. Fully S-100 Bus Compatible - All lines fully buffered. Dip Switch Addressable in two8K block, 4K increments. Write Protectable in 2 blocks, Memory Disable using Phantom, Battery back up capability. Bank Select - Using output port 40H (Cromemco software compatible)-addressable to 512KB of Ram for time share or Memory Overlap, also has alternate ports 80 H, COH. Guaranteed - Parts and labor for one year. You may return the undamaged board within 10 days for a full refund. Orders - You may phone for Visa, MC, COD ($4 handling charges for COD) orders. Personal checks must clear prior to shipping. Shipping-Stock to 72 hours normally. Will notify expected shipping date for delay beyond this. Illinois residents add 5% tax. Please include phone number with order. S.C. digital P.O. Box 906 Phone: Aurora, I L 60507 (312)897-7749 partitioning of the system into cards within the 6-slot backplane previously described. Designing The Logic Of The System The task at hand is to design the central processor card for this homebrew computer. This is the starting point for the design of the whole system. Detail choices made in the processor card's arrangement impact every other card designed for the system. We know, that the system must have 16 address lines and 8 data lines because it uses a 6809 processor architec- ture, and simplicity dictates avoidance of extra logic for memory paging schemes. But which 24 lines of the 40 re- maining in the backplane bus should be committed to which particular uses? Every board in the system must be consistent with this detail choice. The choice is made trival by the fact that, except for aesthetic and symmetry reasons explained below, one backplane line is as good as the next. If we were building a computer consistent with plug compatible backplane bus designs such as the SS-50 of Southwest Technical Products Corporation, or the In- stitute of Electronic and Electrical Engineers (IEEE) S-100 standard bus, these choices would be crucial to that goal of plug compatibility. However, a homebrew system is a homebrew system, so our plug compatibility will be at the level of integrated circuits, not at the level of backplane buses. Designing The Logic Of The System — Backplane Setup As noted in the July BYTE page 194, the power supply wiring of the backplane has been committed to the outer- most pins of the sockets. The assignment of power supply pins used 32 of the 72 pins available, in order to take advantage of the heavy copper wires of the buses. The power supply wiring commitments were made consistent with a symmetry principle: if a board should be inadvertently rotated 180 degrees and plugged in, all power buses will map into identical power buses. The outermost power bus is the — 12 V analog power bus. Proceeding inward, the next symmetric pair will be used for the +12 V analog power; the next pair of buses is for the +5 V main logic power supply. The innermost power buses are the central system ground buses. In table 1, a listing of backplane bus connections, these initial assignments of power pins are shown in shade (a). The power supplies used in building this system are provided by relatively inexpensive modular building blocks from James Electronics. The +5 V logic power is provided by a single regulated supply rated at 6 A. The 2 analog supply voltages are provided by separate modules rated at 1 A. In the photographs of the physical hard- ware, these modules are shown as mounted, prior to wiring. In the design of the backplane bus once the power sup- ply committments have been made, the next items to con- sider are the data and address lines. Continuing the pro- cess of symmetrical allocation, the 16 address lines and 8 data lines should be assigned to bus pins in such a manner that if a card is rotated, data lines will map into data lines, and address lines will map into address lines. The address lines are split into 2 groups of 8 connections on either side of the symmetry axis. The data lines are 204 September 1979 © BYTE Publications Inc Circle 331 on inquiry card. ONE PACKAGE DOES IT ALL Includes these Application Programs . . . Sales Activity, Inventory, Payables, Receivables, Check/Expense Register, Library Functions, Mailing Labels, Appointments, Client/Patient Records 'MICRO-AP MICRO-AP MICRO-AP MICRO- AP MICRO-AP MICRO-AP MICRO-AP MICR P MICRO-AP MICRO-AP MICRO-AP MICRO- RO-AP MICRO-AP MICRO-AP MICRO-AP MICR O-AP MICRO-AP MICRO-AP MICRO-AP MICRO- ICRO-AP MICRO-AP MICRO-AP MICRO-AP MICR XRO-AP MICRO-AP MICRO-AP MICRO-AP MICRO- iP MICRO-AP MICRO-AP MICRO-AP MICRO-AP MICR MICRO-AP MICRO-AP MICRO-AP MICRO-AP MICRO- i-AP MICRO-A P MICRO-AP MICRO-AP MICRO-AP MICR ~|MICRO-AP MICRO-AP MICRO-AP MICRO- mp MICRO-AP MICRO-AP MICRO-AP MICR ■MICRO-AP MICRO-AP MICRO-AP MICRO- |\P MICRO-AP MICRO-AP MICRO-AP MICR IMICRO-AP MICRO-AP MICRO-AP MICRO- IvP MICRO-AP MICRO-AP MICRO-AP MICR AP MICRO-AP "BB^^m ^— ^"""Bi BOAP MICRO-AP Ml RO-AP MICRO-ARM B KRO-AP MICRO-AP t AP MICRO-AP mB ■ Bj^KffwjH Bo-AP MICRO-AP Ml RO-AP MICRO-ARM BcRO-AP MICRO-AP > AP MICRO-AP mB H___^^^B|a Bo-AP MICRO-AP Ml RO-AP MICRO-ARM BdRO-AP MICRO-AP H AP MICRO-AP mB Bo-AP MICRO-AP Ml RO-AP MICRO-ARM BpRO-AP MICRO-AP t AP MICRO-AP MICRO-AP MICRO-AP MICRO-AP MICRO-AP MICRO-AP Ml RO-AP MICRO-AP MICRO-AP MICRO-AP MICRO-AP MICRO-AP MICRO-AP K AP MICRO-AP MICRO-AP MICRO-AP MICRO-AP MICRO-AP MICRO-AP Ml RO-AP MICRO-AP MICRO-AP MICRO-AP MICRO-AP MICRO-AP MICRO-AP * RANDOM, MULTI-KEY RECORD RETRIEVAL under CP/M, CDOS, IMDOS, ADOS SELECTOR Ml ALLOWS INSTANT RECALL OF ANY RECORD USING ANY IN- FORMATION ITEM IN THE RECORD. That statement deserves re-reading, be- cause that ability makes SELECTOR III the most powerful Date Base Man- agement System in micro- computers today! With SELECTOR III you can... • define a record format, assign retrieval keys, and begin entering data in min- utes. • create sorted pointers to records matching your spe- cif or range of requirements. Circle 213 on inquiry card. • automatically generate reports with control-break summaries and unlimited variety. an application on- hours instead of • bring line in months SELECTOR III comes com- plete with eight application programs that perform the tasks listed at top of page. And, since it's distributed in source code form, you can easily add subroutines to do specific computations or file updates. SELECTOR III runs under CBASIC Vers. 1 or 2, and is priced at $295. SELECTOR III-C2 is dedicated to Vers. 2 only, runs about twice as fast, and costs $345. Both systems are available in a variety of CP/M, diskette size and density formats including IBM 8"; North Star; Micropolis; TRS-80; Pro- cessor Tech Helios II; Altair; iCOM; Dynabyte; Imsai; and others. | Available from computer stores nationwide: I LIFEBOAT Associates 2248 Broadway, Suite 34, New York, N.Y. 10024 • (212) 580-0082 Or order direct from ■ MICRO-AP ■ 9807 Davona Drive, San Ramon, CA 94583 I (415) 828-6697 | I BYTE September 1979 205 allocated into 2 groups of 4 connections. Continuing the listing of the backplane connections in table 1, these assignments of 24 address and data pins are shown in shade (b). At this stage in the allocation of logical signals to the bus, 24 of 40 available pins have been used, leaving 16 pins still to be determined. The next item to consider is the set of lines which con- (-12V)-- -- (-12 V)-- = = = = =(+12 V) = = = = = =( + 12 V) = 1 3 : : ; : = A4 X:X : : : x : x : : : : : : : : : x : x : x : x : : 1 4 •:•;' = A5'+:;:;:;:+:;:+:;:;x;:;:;:;:;:;:;:;:; 1 6 :•:• =.A7 ;x+:::;:;x::::::::::::::::;::::::x; 1 7 = RESET 18 = NMI 19 = unassigned 20 = ENABLE 21 = 14 •: 22 d 15 j; 23 = 16 |: 24 = 17 : : 25 : : X=.D4'. 26 :•:>= D5: (a) (b) = 72 71 70 69 + + + + + + + MAIN PWR ( + 5 V) + + + + + + + 68 + + + + + + + MAIN PWR ( + 5 V) + + + + + + + 67 GROUND (0 V) 66 GROUND (0 V) 65 9 : x = ao y^v'xjxoxlx^xjxjxlxlxjxjxjxjx '■:'■: 64 10 8'= Ai'Sx'xxS^ di ='•:•: 63 1 1 :•:■ = . A2 i&SS&S:^^ R? f. x : 62 1 2 x : '= A3 "^S^:^SS^SS^S:§SSSSS:^ D3 =' : : : : 61 10 = 60 11 = 59 12 = 58 13 = 57 QENABLE = 56 unassigned = 55 IRQ = 54 RW = 53 ^i^x+x "as '= *: 52 x+x'+x'l "A9^=:x 51 ;:-:-:jSjij:-:Aio =;:•: 50 :•*:*:** Ali'=: : : : 49 : A12 = : x 48 : A13 = :>: 47 27 :x:=.P6;xjxj:v:x:;:j:vx;:j:v:x:v:;:v:v:x:x:xXv:x:;:;x;AH = ::j: 46 28 :*:= .^J:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-S^ .=.:•:: 45 29 GROUND (O V) 44 30 GROUND (0 V) 43 31 + + + + + + + MAIN PWR ( + 5 V) +++ + + + + 42 32 + + + + + + +MAIN PWR ( + 5 V)+ + + + + + + 41 33 = = = = = = = = =(+12 v)= = = = = = = = = 40 34 = = = = = = = = =(+ 12 V)= = = = = = = = = 39 35 - ( - 1 2 V) 38 36 ( - 1 2 V) 37 (c) = nect the central processor to the external world. These lines are the essential timing and control signals which define the discipline of the bidirectional 8-bit bus used by the microprocessor. In the specifications of the 6809, the following signals are defined which have relevance to the outside world: • RW = Read versus Write bus direction relative to the processor. • ENABLE = Clock ouput ("Phi 2") of processor. • QENABLE = Quadrature clock of processor. • RESET = system reset line to processor and all peripherals. • MRDY = memory-ready line, for use with slow memory devices. • BREQ = bus request for direct memory access (DMA). • BA = bus available. • BS = bus status. • FIRQ = fast interrupt request. • IRQ = interrupt request. • NMI = nonmaskable interrupt request. The simplest and most direct way to deal with these 11 signal lines would be to bring them out to the backplane. But do we really need all these signal lines in this pro- cessor? Might it be more useful to commit a majority of the remaining 16 lines to interrupt activities, rather than having nonessential copies of the lines coming from the processor circuit? For example, we may prefer to incor- porate 8 separate interrupt lines in order that each of a possible 8 peripheral devices could have a dedicated line. If this is to be accomplished, then the total commitment of noninterrupt lines to the backplane must be 8 lines instead of the mixed selection of 3 interrupt lines and 8 signal lines shown above. How can we modify this set of backplane signals given the limitations and purposes of this particular design? First, remember that this application is a simple and limited one in which no direct-memory access is being implemented, and that all memory will be fast enough to drive the processor at full speed. Given this requirement, the 2 signals memory ready (MRDY) and bus request (BREQ) can be removed from the set seen by the external world beyond the processor card. We have thus reduced the backplane line count to 9 lines, nearly enough to allow 8 distinct interrupt lines. The next items to question are the bus available (BA) and bus status (BS) signals. These are used to decode 1 of 4 possible states: normal operation, interrupt acknow- ledge, synchronization acknowledge, and bus grant (halt acknowledge). Of these, the limited goals of the present Table 1: An allocation of backplane signals. As described in the text, this backplane signal set provides for 8 bidirectional data lines, 16 address lines, 8 individual fast interrupt lines used with a (slow) software polled strategy, 2 direct interrupt lines, and 4 essential timing signals for the 6809 and its relationship with the external world. The assignment of these lines is kept sym- metrical, so that while the processor may not work if any board in the system is inadvertantly plugged in the wrong way, no major conflicts will occur that could damage a gate or buffer. The shades indicate stages in the backplane allocation process described in the text: (a) pins are the power connections; (b) pins are the address and data connections; (c) pins are the 16 lines allocated to processor control signals and interrupts. 206 September 1979 © BYTE Publications Inc FALL 1979 0001010111 110100010101 110101000000010000101 11110100010101011 11 10100010101110 JAM€S MARTIN S€MINAR 00010101 1 1 1 10100010101 1 1010100000001000010101 1 1 1 10100010101 1 1010100000001000 Future Strategy, Management, & Design for: ■ Distributed Processing ■ Data Base ■ Networks ■ Corporate Strategy Washington, D.C. October 15 Los Angeles October 22-26 Boston November 5-9 Chicago November 26-30 Seminar Fee: $1150.00 ■•- • .. _ __. : . 0001010111110100010101110101000000010000101011111010001010111010100000001000 CALL OR WRITE: (213)476-9747 Circle 364 on inquiry card. P.O. BOX 49765, LOS ANGELES, CA.90049 (213)476-9747 BYTE September 1979 207 WANTED: ASSISTANT EDITOR ?n Job Opportunity onComputing , BYTE's companion magazine, is growing rapidly. We have an immediate opening for the job of assistant editor of onComputing , a McGraw-Hill d publication. This creative opportunity offers the potential for growth in the,, exciting world of publishing. Candidates for this position should have a firm grounding in personal computer hardware and software, and should have the ability to write and edit clearly and accurately. A technical degree and some journalism experience are desirable but not mandatory. «C;._ onComputing covers the world of personal computing, but is written in a less technical style than BYTE. It is aimed at the beginner, professional person, student, and anyone interested in learning more about personal computers. onComputing is located in Peterborough NH, the heart of the southern New Hampshire vacation region. Conveniently located 90 minutes from Boston, Peterborough offers the benefits of a wide variety of cultural activities, plus the peaceful seclusion of the country. If this position sounds interesting, we'd lixe to hear from you. Send your resume in confidence to Chris Morgan, Editor-in-Chief, onComputing , 70 Main St, Peterborough NH 03458, or call (603) 924-7217. Time is of the essencel system make the only externally relevant state "normal operation" if we can confine interrupt handling logic to the processor card. Can this be done? The answer is "yes", if we define fixed read-only memory vectors for all interrupts, and eliminate the need to decode interrupt acknowledge externally for purposes of altering the inter- rupt vector locations. Thus the backplane signal require- ments have been further reduced to 7 lines, still allowing the 3 originial interrupt lines to come out to the external world off the central processor card. Now let's examine the interrupt handling capabilities of the processor. Of the 3 available interrupts, the fast inter- rupt is the most general. The reason for this is that it only stacks away the essentials of the processor state when acknowledging the interruption with a branch through the FIRQ vector location, hexadecimal address FFF6. These essentials are the condition code, and the return address. In contrast, the NMI and IRQ interrupts always stack away the entire current contents of the central pro- cessor's set of registers. If we use the FIRQ signal for most interrupt activity, then, when speed is needed, only those registers which are used by the interrupt routine can be stacked away using the multiple register push and pull instructions. If the operation of the NMI or IRQ (ie: com- plete protection) is required, the multiple register opera- tion of push and pull can be extended to cover all the pro- cessor registers using the proper "post-byte" which selects registers. What about devoting the FIRQ interrupt input to 8 dif- ferent possible sources, using a concept of a software- polled flag register and a parallel input port to prioritize "who called"? This elminates 1 more line from the original backplane signal requirements, while adding 8 interrupt lines labeled 10 through 17. We keep the NMI and IRQ lines available for truely high-priority interrupt signals which must go in directly without much software decoding. Our result then is the final backplane signal set listed in table 1, with this last set of additions shown in shade (c). Two lines are left uncommitted at this stage, in case an essential signal concept is omitted. One or more interrupt lines (10 through 17) can be sacrificed, if more than 2 lines must be added due to some shortcomings. With this general discussion of the system's backplane complete, I will continue these notes next month with a more detailed sketch of the system's most important card: the central processor module. Following this design discussion, the final installment on the processor module will be a short description of the detailed schematic as I wire it. ■ Articles Policy BYTE is continually seeking quality manuscripts written by indi- viduals who are applying personal computer systems, designing such systems, or who have knowledge which will prove useful to our readers. For a more formal description of procedures and requirements, potential authors should send a large (9 by 12 inch, 30.5 by 22.8 cm), self-addressed envelope, with 28 cents US postage affixed, to BYTE Author's Guide, 70 Main St, Peterborough NH 03458. Articles which are accepted are purchased with a rate of up to $50 per magazine page, based on technical quality and suitability for BYTE's readership. Each month, the authors of the two leading articles in the reader poll (BYTE's Ongoing Monitor Box or "BOMB") are presented with bonus checks of $100 and $50. Unso- licited materials should be accompanied by full name and address, as well as return postage. 208 September 1979 © BYTE Publications In Model DMB-6400 Series dynamic 64k byte RAMS incorporate the features which are standard in the DM-6400 Series and adds the following capabilities: • ALPHA MICRO, CROMEMCO, and NORTH STAR output port bank select compatible. • Four (4) 16k byte, functionally independent memory banks. • Memory bank size can be incre- mented to 64k bytes in 16k increments. • Eight (8) 64k byte banks of mem- ory per output port. Model DM-6400 Series dynamic 64k memory boards feature IEEE S-100 compatible timing and on board transparent refresh. • Memory selectable and deselec- • 25 MHz on board crystal oscillator table in 4k byte increments. for independent timing. DMB-6400 and DM-6400 Common Features: • 4 MHz Z80 operation with no wait states. • Tested and bumed-in. • Low power- 8 watts maximum. • Reliable, expandable memories. ONE YEAR GUARANTEE THE FOLLOWING PRODUCTS ARE AVAILABLE FROM YOUR LOCAL DEALER. □ DMB-6400/64KRAM □ DMB-4800/48KRAM □ DMB-3200/32KRAM □ DMB-1600/16KRAM □ DM-6400/64KRAM □ DM-4800/48KRAM □ DM-3200/32KRAM □ DM-1600/16KRAM U.K. & EUROPEAN REPRESENTATIVE: ABACUS COMPUTERS LTD 62. NEW CAVENDISH STREET LONDON. W1M 7LD U.K. TEL: 01-580/8841 TELEX: 881-3065 AUSTRALIAN REPRESENTATIVE: COMPUTERLAND OF MELBOURNE 555 COLLINS STREET MELBOURNE. VIC3000 TEL: 625581 MEASUREMENT systems &. controls incorporated 867 North Main Street • Orange, CA 92668 Telephone: 714/633-4460 Circle 215 on inquiry card. BYTE September 1979 209 Circle 133 on inquiry card. Circle 198 on inquiry card. Belais' Master Index to Computer Programs in BASIC Gives You Access to $14,836.14 Worth of Computer Programs for Just $7.95! Now Available Off-The-Shelf You paid hundreds or even Ihousands of dollars lor your new microcomputer. 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A brief index line capsulites Ihe review for quick reference Source information shows you where the program can be found. Any updates or corrections are shown so you know the program is accurate and complete. The lext of the review gives you a full description of what the program does. In addition, Ihe review gives detailed technical information about what hardware and software the program needs. Everything you need to know is right at your fingertips! We don't provide the program listings them- selves, of course. But we do tell you where you can pick them up — even ones that appeared in print years ago. You don't have to be a programming wizard to use Belais' Master Index. That's because BMI lists only finished, ready-to-mn programs in BASIC, the easy-to-use language enjoyed by millions. Even if you're a master programmer, you'll appreciate Belais' Master Index. Why slave away hours, days, or even weeks writing a program when someone else has probabfy already done the work for you? These programs are working, documented, and ready-togo. Programs like: Circuit Design, Psychoanalysis, PASCAL Compiler, Forrester's World Simulation, and Color T.V. Tester. Never again will you have trouble answering that question. "But what are home computers good for?" Then again, there's always MONEY. Maybe you haven't (hough of all the ways your "fun" com- puter could turn out a little of the green stuff for you. Maybe you haven't — but a bt of other people have, and they've written up their ideas for you to use. Belais' Master Index lists dozens of pro grams that you can use to set up your own business If you already have a business. Betas' Master Index has the programs to turn your home com- puter into a full-fledged business system. General ledger, billing, payroll, mailing lists, word proces- sing^ — no matter what type of business you have, Belais' Master Index has the programs you need, All this and save $2.00, too! The cover price of Belais' Master Index to Computer Programs in BASIC is $9.95. But because you're buying by mail, we don't have to pay a commission to a bookstore. So we're going to pass (he savings along to you. Order now and you can get your copy of Belais' Master Index for just $7.95! To order, write you name, address, and the words "Beiais' Master Index" on a piece of paper. Make out your check for $7.95 plus $1 shipping (Calif, residents add 54$ sales tax). If you want to use your VISA or Master Charge card, give the total for your order, your account number, the expiration date of your card, and your signature. Send your order to Falcon Publishing. Dept. T. 140. Riverside Ave. P.O. Box 688. Ben Lomond, CA 95005. We absolutely guarantee you'll find Belais' Master Index one of the most useful books on your shelf. If you're not completely satisfied, return it to us within 30 days and we'll refund every cent you paid. You can't lose, so order NOW? 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Box 864 ■ Michigan City, Indiana 46360 Please ship the following: NATIONAL TECHNICAL SCHOOLS 4000 South Figueroa Street • Los Angeles, California 90037 Please rush your FREE 65-page color catalog Name Dept. 217-039 Address . City State . D CRAPS $6.95 D BIO-RYTHM $5.95 D ALL 4 PROGRAMS $19.00 Blank CIO Cassettes - Quantity NAME D BIG SIX D CALENDAR $5.95 $4.95 ADDRESS CITY/STATE/ZIP .ZIP. D Check D Money Order I □ Check if interested in G.I. Bill information. | □ Check il interested ONLY in classroom training in Los Angeles L..«.. 210 BYTE September 1979 Circle 279 on inquiry card. Complete money back guarantee. No questions. Personal checks accepted. We trust you. All shipments made in 10 days. Circle 101 on inquiry card. Circle 287 on inquiry card. # Omikron transforms TRS-80* into a powerful business system. STANDARD DRIVES 8" Drives give you 5 times the speed and 3 times the storage of your mini drives! Our system provides a standard Shugart interface so you can use either your 8" drives or ours. Omikron drives are enclosed in an attractive metal cabinet, and include a power supply. SOFTWARE CP/M* is the most popular operating system for microcomputers. But many high-level languages and advanced business programs cannot run with the special CP/M* designed exclusively for the TRS-80* The Omikron MAPPER with standard CP/M* allows you to expand your software capability to go beyond the few available TRS-80* compatible packages. TRS-80* with MAPPER out-performs systems costing $1000 more The MAPPER I and MAPPER II are plug- in modules. They don't require any circuit changes, are easy to install, and they don't interfere with the normal operation of your TRS-80? All your original software, includ- ing Level III BASIC will still run properly. 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Prepaid orders given top priority. *CP/M is a TM of Digital Research. TRS-80 is a TM of Tandy Corporation. PROFESSIONAL INCOME TAX PROGRAMS FOR TRS-80™ Accountants, lawyers, tax consultants nationwide, prepared over 30,000 1978 Federal tax returns using our system. Displays and fills in Form 1040 and related schedules on the screen, then prints out the completed forms automatically. Change your mind? Make an error? Correct a single entry and you have a brand new form with all re-computations made automatically. No tax system, running on any computer anywhere, has all the features of our professional system, and yet— Our base program, which does 1040 and Schedule A costs only $189.95 And! You can add schedules for only $37.95 each, customizing your system to your requirements. CONTRACT SERVICES ASSOCIATES 706 SOUTH EUCLID ANAHEIM, CA 92802 TELEPHONE (714) 635-4055 FREE CATALOG AND BROCHURE TO PROFESSIONALS Circle 82 on inquiry card. BYTE September 1979 211 Circle 18 on inquiry card. 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Ask your local dealer or send your check to: Automated Simulations Department Y P.O. Box 4232 Mountain View, CA. 94040 California residents please add 6% sales tax 6800 DEVELOPMENT SOFTWARE An integrated applications development and execution system. SDOS All devices interrupt-driven including typehead. Provides device independent, byte addressable random files. Supports any mixture of floppy or hard disk drives up to 2.5 billion bytes. Sector read-ahead and buffer pool enhance application perfor- mance. Flexible: Currently runs on 7 manufacturers' systems, using 10 different drive/controllers, including mini-floppies and hard disk. BASIC COMPILER For speedy business applications. 10 digit BCD; random access to variable size records; long variable names; formatted out- put; if-then-else; error trapping. Field proven for over 2 years. EDIT A powerful text editor with change, delete, replace commands. Automatic display of modification or context changes; macro facilities for complex or repetitive editing. ASM 2 pass conditional assembler; 32 character labels; symbol table dump and cross-reference; error cross-reference; extensive arithmetic and listing control. IOB Single-step, multiple, real time breakpoints; memory dump; multiple display modes. No special hardware needed. Over 500 pages of documentation to match this proven soft- ware. Complete package: $760.00 Also (not including SDOS) available for SWTP, Exorcisor, SSB and MSI DOS. Write for free catalogue. Sizable distributor discounts. SOFTWARE DYNAMICS 2111 W. Crescent Avenue, Suite G Anaheim, CA 92B04 (714)635-4760 TRS-80 disk software DISKETTE DATA BASE IDM-III 32K $49 You can use it to maintain a data base & produce reports without any programming. Define tile parameters & report formats on-line. Features key random access, multi-keys, sort, select, field arith, audit log. Almost use up all 32K. ACCOUNT manage client accounts & account receivable. Automatic billing & transaction recording. Print invoices and reports. 32K req. $59. WORD PROCESSOR 16K $39 Our WORD-HI is the first word processor specifically designed for TRS-80 that uses disk storage for text. Written in BASIC. No special hardware and text limit. Use for letters, manuals & reports. MAILING LIST 16K $35 It lets you maintain data base and produce reports & labels sorted in any field. Random access. 2-digit selection code used. INVENTORY 16K $39 While others use inefficient sequential file, we use 9-digit alphanumeric key for fast on-line random access. Record has key, description, level, safety level, order ami, unit cost & price, annual usage, location and vendor code. Reports give order info, performance summary, etc. KEY RANDOM-ACCESS UTIL 16K $19 Lets you access a record by specifying a key. Features hashing, blocking, buffering technique, auto I/O error retry, etc. MICRO ARCHITECT 96 Dothan St. Arlington, MA 02174 'TINY' PASCAL tor TRS-80® & NORTH STAR® Now you too can have Pascal! The Chung/Yuen 'Tiny' Pascal has been specially designed for TRS-80 & North Star owners. The full power & elegance of 'Tiny' Pascal is at your command. Programs written in 'Tiny' Pascal run at least 4 times faster than the same program in BASIC! 'Tiny' Pascal is also a great way to learn Pascal Programming, & fun too. The minimum system requirements are: Level II, 16K for TRS-80, (no disk required) & 24K for North Star (specify density). SOURCE TOO! But most important, you also get source to 'Tiny' Pascal written in Pascal with each purchase! You can even compile the com- piler! (Requires 36K for North Star systems, & 32K, Level II for TRS-80). You can customize your own version, or just use it the way it is. 'Tiny' Pascal is a subset of Standard Pascal & includes. RECURSIVE PROCEDURE/FUNCTION, IF-THEN-ELSE, REPEAT/UNTIL, 'PEEK & POKE', WHILE, CASE, & MORE! (Plus full graphics for TRS-80 as well) Also you can save & load programs. You get all this & more, plus a user's manual for $40.00. available from: /mm/on P.O. Box 1628 Champaign, IL 61820 (217) 344-7596 ^ All orders pre-paid, Illinois residents add 5% sales tax 212 BYTE September 1979 Circle 214 on inquiry card. Circle 359 on inquiry card. Circle 102 on inquiry card. BYTE BACK ISSUES FOR SALE The following issues are available: 1976: July 1977: March, May thru December 1978: February, October, December 1979: January thru August Cover price for all issues thru August 1977 is $1.50 plus $.25 postage and handling ($3.50 total foreign). September '77 thru '79 issues are $2.00 plus $.50 postage and handling ($4.00 total foreign). Send requests with payment to: BYTE Magazine 70 Main St, Peterborough NH 03458 Attn: Back Issues KITE )[ Good Buys From Disks, Etc. Verbatim MINI-DISKS 10 for $29.00 or 3 for $10.00 New! Verbatim Digital Quality Cassettes For Personal Computers Professional quality cassettes feature leader-free, splice- free, premium grade tape, precision engineering features. For top performance in popular personal computers, including Apple, PET, Heathkit, Atari and Mattel. 2 for $5.45 1 P^ Mini-Disk Protectors Fit 3-Ring Binders Tough, glare-proof vinyl. Holds 2 diskettes and ID cards. 75* ea., 10 for $5.75 Storage Cases Made of durable, molded plastic. Choice of black or beige. Maxi Case, $4.25 Mini Case, $3.75 MasterCharge, ^ mm m p Q Box 327 c Chicks OK. Disks, Etc. Center Valley, No COD's. 18034 SPECIALIZING IN QUALITY MICROCOMPUTER HARDWARE INDUSTRIAL • EDUCATIONAL • SMALL BUSINESS • PERSONAL BUILDING BLOCKS FOR MICROCOMPUTER SYSTEMS, CONTROL & TEST EQUIPMENT WIRED: $295.00 R 2 I/O 2K ROM 2K RAM 3 Serial Ports 1 Parallel Port KIT: $279.00 WIRED: $310.00 16 K RAM FULLY STATIC MEMORY KIT: $200.00 WIRED: $250.00 ECT-100-F RACKMOUNT CARD CAGES ECT- *>-„„„: vechn. POWER SUPPLIES, CPU'S, MEMORY, OEM VARIATIONS KIT: $340.00 WIRED: $395.00 TT-10 TABLE TOP MAINFRAMES 763 RAMSEY AVE. HILLSIDE, N.J. 07205 ELECTRONIC CONTROL TECHNOLOGY ( 2 od bsg-boso Circle 120 on inquiry card. BYTE September 1979 213 What's New? Low Cost Computer Assisted Instruction APPILOT language is an Apple II ver- sion of the standard computer assisted instruction (CAI) language, PILOT. Using lesson files created by the APPILOT pro- gram editor, APPILOT creates multi- media learning experiences with text, graphics and sound. The student can in- teract with APPILOT using both numbers and words which APPILOT recognizes as student input. APPILOT conforms closely to the pro- posed common PILOT standard, but it incorporates features that fully use the capabilities of the Apple II computer. Among these features are color graphics commands, a musical minilanguage, and disk commands for lesson segmentation which give an effective lesson size up to 90 K bytes. APPILOT also links to the Ap- ple's integer BASIC to allow full calcu- lation capacities. APPN OT is available on tape and disk, and is offered on Super Load tapes and for those Apple owners who wish to run prewritten APPILOT lessons. For $17.95 the user can execute APPILOT lessons on a 16 K byte Apple, using only tape storage. Included on the tape is the interpreter and a demonstration lesson about APPILOT. Also provided is a documentation manual for running APPILOT and for linking it with the MUSE APPEN-I Text Editor, which may be used for creating and editing APPILOT lessons. For institutions that wish to write as well as use APPILOT lessons, the CP/M Text Editor ED-80 is a text editor designed to run under CP/M and derivative operating systems on 8080, 8085, and Z-80 disk based systems. A user's manual of over 60 pages describes both implementation and usage. ED-80 has a simple command structure patterned after the University of Maryland's editor for UNIVAC 1100s. Over 50 commands are provided, includ- ing forward or backward locate, change, and find commands; insert, delete, append, print, list, macro, case, scale, tabset, and window commands; and get and put commands for copying, moving, merging, and duplicating edit files and program libraries. An internal location counter is maintained for dis- playing with text, prompting for user input, and for line positioning. ED-80 provides a window approach to text editing that is not hardware APPILOT Edu-Disk converts a 32 K byte Apple with disk into a complete CAI system. The user can develop lessons, store them on disk, and run them with the APPILOT interpreter. The Edu-Disk comes with interactive lessons that in- struct the user on all aspects of the APPILOT CAI development system. The APPILOT Edu-Disk is being offered for $49.95 which includes a detailed documentation manual. For further in- formation, contact MUSE, 7112 Dar- lington Dr, Baltimore MD 21234. Circle 565 on inquiry card. Machine Language Programs for the PET Computer The SYS7171 and the SYS8181 are two new machine language programs for the PET 2001 computer. SYS7171 is a machine language monitor which allows a programmer or PET user to program in machine language, or in BASIC, without destruction of the monitor once it is loaded. Programs may be saved, loaded or rewritten yet SYS7171 remains coresi- dent and undisturbed. SYS8181 is a machine language re- numbering program which requires only 1 K byte of programmable memory for its operation. After it is loaded, the user can load a BASIC program and it will be renumbered in seconds. SYS7171 sells for $29.71 and SYS8181 is priced at $18.71. For further informa- tion, contact National Artificial In- telligence Laboratory, POB F, Mobile AL 36601 . Circle 566 on inquiry card. Word Processing Software System Autoscribe is a professional word processing system designed for the business world. With Autoscribe, typed text appears on a video terminal screen as it will be printed, and corrections, deletions or revisions can be made in seconds. The finished document is typed at hundreds of words per minute. Letters, contracts and other documents can be produced quickly on single page or continuous form print-out. The ori- ginal data is recorded and saved on the user disk. Documents can be retrieved instantly and reprinted as needed. No computer language is needed. All in- structions are in English. Autoscribe software operates on Z-80 and 8080 sys- tems utilizing North Star disk, a Soroc or Hazel tine terminal and a letter quality printer. For further information contact MicroAge Wholesale, 1425 W 12th Place, Tempe AZ 85281. Circle 567 on inquiry card. dependent. Users may examine and edit data through a one line window as it is moved through the edit file. A window command allows instantaneous full screen displays of both the current line and surrounding lines, with forward and backward scrolling. Compatible with existing CP/M edit files, ED-80 is available on an 8-inch single density disk for $71. For further information contact Software Develop- ment and Training Inc, POB 4511, Huntsville AL 35802. Circle 568 on inquiry card. 16-Digit Scientific Subroutine Package for Microsoft Extended and Disk BASIC Interpreters DPFUN is a comprehensive 16-digit precision scientific subroutine package written for Microsoft extended and disk BASIC intepreters, including TRS-80 Level II BASIC. The 1 3 double-precision exponential, logarithmic, trigonometric, and inverse trigonometric functions pro- vide a valuable utility for engineering and scientific applications. DPFUN uses truncated continued fraction algorithms that result in easily entered code, fast execution, and full exploitation of the precision that is available in 64-bit binary floating-point notation. The com- plete set of subroutines occupies approxi- mately 2.5 K bytes. The DPFUN source code only is available for $10 postpaid. For further information contact Miken Optical Co, 53 Abbett Av, Morristown N J 07960. Circle 569 on inquiry card. Elementary Math Tapes for TRS-80 The Microcomputer Mathematics Pro- gram K-8 consists of a set of tapes for drill, practice and tutorial in addition, subtraction, multiplication, division, fractions, numeration and decimals for kindergarten through 8th grade. The tapes are programmed for use on a Radio Shack Level II BASIC TRS-80 microcomputer and 16 K bytes modified memory. The teacher's manual gives an overview of the program, suggests ways to use the program, correlates the skills to selected mathematics texts, and pro- vides suggestions for individualizing math instruction. One set of microcom- puter Mathematics Program K-8 tapes in- cluding the teacher's manual is $995. For further information, contact Foundation for Quality Education Inc, 802 Mer- chants State Bank Building, 5217 Ross Av, Dallas TX 75206. Circle 570 on inquiry card. 214 September 1979 © BYTE Publications Inc Circle 12 on inquiry card. A COMPLETELY REFURBISHED "SELECTRIC" ASCII TERMINAL FOR THE SMALL BUSINESSMAN OR SERIOUS HOBBYIST. The AJ 841 I/O terminal. Now available from dealers nationwide. Demand for our AJ 841 I/O computer terminal has been great. And now it's getting even greater. So call your local computer shop dealer right away. Supply is limited! You may never have another opportunity like this one to buy your own professional terminal. The A J 841 features: ■ Choice of serial RS 232 or parallel interface • ASCII code • 14.9 cps printout • High quality Selectric printing • Heavy-duty Selectric mechanism • Off-line use as typewriter • Documentation included • 30-day warranty on parts and labor (details available on request) Call toll-free now For location of your nearest AJ dealer, call toll-free: 800/538-9721 California residents call 408/263-8520. l« oV.*°* 'd from Computer Headware . . . the Self-Indexing Query System for your Apple II, North Star, or CP/M machine Distributed by: . Information Unlimited / 219-924-3522 P.O. Box 8372. Merrillville, Indiana 46410 ■ Lifeboat Associates / 212-580-0082 (CP/M model only) 2248 Broadway, Suite 34, New York City 10024 . Structured Systems Group, Inc. / 415-547-1567 5208 Claremont Avenue, Oakland, California 94618 BYTE September 1979 215 What's New? MISCELLANEOUS Computer Communication at Your Fingertips VuePoint is a touch input display panel that measures only V/x inches thick. Vuepoint's 12 line by 40 character flat panel also provides a unique touch input capability. This approach permits efficient and speedy operator inter- action using menu-driven displays. Vue- point's microprocessor based controller provides all standard smart video features plus the following: touch response in matrix or screen echo modes, multiple display buffers, and alternate character sets. Communication is by standard 300-19200 bps asynchronous RS-232 protocol. Options include wall or rack mount, auxiliary printer, and 128 character ASCII keyboard. Vuepoint is priced at $3500. For further information, contact General Digital Corp, 700 Burn- side Av, E Hartford CT 06108. Circle 571 on inquiry card. APL/Z-80 Release 2.0 Vanguard Systems Corp, 6812 San Pedro, San Antonio TX 78216 has an- nounced the release of version 2.0 of APL/Z-80, an APL interpreter for Z-80 based microcomputers. APL/Z-80 in- cludes the following features: dynamic execution of system commands; serial printer support; shared variables; aux- ilary processor for I/O (input/output) ports which allows complete device control using defined APL functions for any device interfaced to the Z-80 I/O port; and auxilary processor implemen- tation of a file system featuring a dir- ectly indexable file having variable length records, each of which can be an APL array of arbitrary type, shape, and size (up to available workspace). A workspace containing defined APL/Z-80 functions, implementing each of the primitive functions not present in this version of APL/Z-80, is distri- buted with each system. The hardware required is a Z-80 processor, a disk drive, and either serial ASCII APL console terminal or ASCII keyboard and video display board compatible with the Vector Graphic Flashwriter or Processor Technology VDM-1. The end user license for use on a single processor is $350. Circle 572 on inquiry card. Distributed Computer System Based on Personal Computers Cluster/One is a distributed pro- cessing alternative to BASIC timesharing. The central Cluster/One unit (the Queen) connects to 15 personal microcomputers (the Drones), via a high-speed parallel data bus (the Clusterbus). An optional feature provides support for an addi- tional 15 Drones. Currently supported as Drone stations are the Apple II, Commodore PET 2001-8, and TRS-80. Programs and data files can be shared among the users of Cluster/One. They are stored on two IBM compatible eight inch floppy disks. Each disk holds up to 315 K bytes of data. Disk data transfer rate is 250 K bits per second, managed by a large scale integration floppy disk controller chip. All data transfers arc cyclic redundancy checked (CRC) and disk writes are automatically verified. Data is transmitted to each Drone sta- tion in packets, with individual error checking. Typical system response time for program loading is two seconds. Cluster/One commands are quite similar to their counterpart cassette tape commands. Disk commands may be imbedded in user programs, permitting menu-driven program loading or chain- ing. Cluster/One comes with a full set of utility programs for system maintenance and backup, along with separate doc- umentation for the end users. Prices begin at $45 00 and vary with the parti- cular configuration and options selected. For further information, contact Nestar Systems Inc, 810 Garland Dr, Palo Alto CA 94303. Circle 573 on inquiry card. Where Do New Products Come From? The information printed in the new products pages of BYTE is obtained from "new product" or "press release" copy sent by the promoters of new products. If in our judgment the information might be of interest to the per- sonal computing experimenters and homebrewers who read BYTE, we print it in some form. We openly solicit releases and photos from manufacturers and suppliers to this marketplace. The information is printed more or less as a first in first out queue, subject to occasional priority modifications. While we would not knowingly print untrue or inaccurate data, or data from unreliable companies, our capa- city to evaluate the products and companies appearing in the "What's New?" feature is neces- sarily limited. We therefore can- not be responsible for product quality or company performance. Heat Scalable Cassette Holder This cassette holder, designated Pocketray, will hold a cassette securely with the title visible. Cassettes are fully protected on three sides. There are 12 Pocketrays to a sheet which is perforated vertically and horizontally. These may be snapped apart into single units or in any multiple to fit the most creative con- figuration. Made of PVC, these cassette holders are easily heat sealed to any vinyl material, with a minimum of tool- ing. Samples, pricing, and literature are available from Charles Leonard Inc, 79-11 Cooper Av, Clendale NY 11227. Circle 574 on inquiry card. 216 September 1979 © BYTE Publications Inc FLOPPY DISK REPAIR • PerSci and Shugart • Quick turnaround • Factory trained on PerSci TKc:';;;; i; !lV>:;;;::::*T^ , T :^t> "^'W COMPUTER SERVICE CENTER 7501 Sunset Blud Hollywood CA 90046 213-851-2226 Circle 68 on inquiry card. GET CONNECTED Connect your S-100 BUS or TRS-80 system to the telephone network and turn it into a terminal. The ^-Phone© is absolutely all you need — it's not just a modem, not just a controller. Just plug the /i-Phone© into your processor and plug it's cable into a standard modular telephone wall jack and you're connected. The fi-Phone© is BELL 103 com- patible and F.C.C. registered. Another Fine Idea From I.D.E.A. 850 Lexington St. Waltham, MA 021 54 617-893-1368 Circle 178 on inquiry card. BASIC/FOUR COMPUTER MODEL 350 Perfect for small to medium sized business applications. Model 350 CPU, 4.2 Mb Disc Drive, Video Display Ter- minal, 1 60 cps Printer, and 6 Disc Cartridges. Under con- tinuous factory maintenance. Full system ready to go $11,000. Contact: Carl Egetter (714) 979-9013 THERMAX SYSTEMS, INC. 3185 "A" AIRWAY AVE COSTA MESA, CA 92626 Come Help Us Celebrate The Child St. Jude Children's Research Hospital continues its search for life-saving knowledge about catastrophic childhood disease. And this search continues because people care. There's no charge to patients or their families, once admitted to its research studies by physician referral. The cost of drugs, equipment, and research programs is met primarily by public contributions. Help us celebrate the child by send- ing your fax-deductible check or request for further informa- tion to St. Jude Children's ^ _ Research Hospital, k A™ 539 Lane Ave., ifej Memphis, TN 36105. Don't Forget! Our New 4K Byte Non-Volatile Memory Boards Won't Let You! • 30 days minimum guaranteed data retention • Ultra low power 450 NSEC static CMOS RAM IC's • On-board regulator, power monitor and battery • S-100 bus compatible Assembled and Tested $395.00 Remember . . . to send for details! 1395 Golf Street Dayton, Ohio 45432 Circle 88 on inquiry card. TRS-80 USERS Three Diskless TRS-80 Programs - Telephone/Address/Mailing list pro- gram - sorts by name or zip code. Retrieves telephone § from name and visa versa. Access time is under 2 seconds, over 100 listings, Level II 16K -$30.00 - Checkbook program - hard electronic copy, easily accessable. 170 listings, Level II 16K -$30.00 - Mandalas for the Cybernectic Age I & II -amazing graphic programs, better than TV - lasts hours without repeating or commercials. 2 sets of four interweaving designs, Level I or II 4K RAM - $30.00 Introductory offer - All 3 for $75.00 Loweco provides complete support Catalog $2.00 LOWECO COMPUTOR 1803 RODNEY LOS ANGELES CA 90027 213-660-7530 6% TAX IN CALIFORNIA Money Order, Cashier Check Speeds Delivery TRS-80, PET, APPLE, SORCERER Hardware/Software Systems Available now: ■ HAM INTERFACE-including the most sophisticated RTTY systems money can buy. ■ Baudot and ASCI I printer interfaces. M Electra Sketch' .ANIMATION GRAPHICS Compiler Write or call for free catalog >VWCROTRONICS,inc. P.O. Box 518 (a ) Keyes, CA 95328 (209) 634-8888 / 667-2888 (R) (S) We are experiencing telephone difficulties, please keep trying. Circle 206 on inquiry card. EXCELLENT BUY: USED CENTRONIC PRINTERS Model 703 $1495. Model 588 S 895. COMPLETE TIME SHARING AND IN-HOUSE SYSTEMS AVAILABLE Texas Instrument 3n Teletype m£ Xerox Intertec Altos Ohio Scientific Exidy Centronics Circle 74 on inquiry card. A Message to our Subscribers From time to time we make the BYTE subscriber list available to other com- panies who wish to send our subscribers promotional material. We take great care to screen these companies, choosing only those who are reputable, and whose products, services, or information we feel would be of interest to you. While we believe the distribution of this information is of benefit to our subscribers, we firmly respect the wishes of any subscriber who does not want to receive such promotional literature. Should you wish to restrict the use of your name, simply send your re- quest to BYTE Publications Inc Att: Circulation Department 70 Main St Peterborough NH 03458 Thank you. Circle 367 on inquiry card. Circle 207 on inquiry card. Wtisfs New? SYSTEMS and MEMORY New Word Processing System Also Supports Data Processing Applications A video based word processing sys- tem capable of handling data processing applications has been introduced by Vector Graphic Inc, 31364 Via Colinas, Westlake Village CA 91361. The new system, called Memorite 2, incorporates the firm's Z80 based MZ microcom- puter with 630 K bytes of disk capacity, their Mindless Terminal, and the Qume Sprint 5, 55 cps printer. For word processing applications, Memorite 2 with dual Micropolis floppy disk drives features advanced text preparation, edit, and delete capabilities. It offers auto- matic letter printing from memory with full formatting techniques such as under- lining, indentation, automatic margins and variable line and character spacing. The system also performs mass mailings, which allow letters to be merged with address lists. Its memory is resident on programmable read-only memory, so users need only type after a "power up and proceed" function. As a data processor, Memorite 2 is capable of performing standard account- ing tasks and custom applications in business BASIC for small firms or departments of large companies. Scien- tific calculations are also available for technical environments. The price for the Memorite 2 is $8,950. Circle 575 on inquiry card. CATCH THE S-100INC. BUS! Vector Graphic 16K Assembled Fast Memory Board Imsai "8080" Kit complete w/Front Panel Computime CT100 Clock, Calendar & Calculator Kit S-100's Three Ring Binder w/Ten Vinyl Jackets for 5 1 A Mini Floppies (Holds Twenty Diskettes Plus Directory Pocket) LIST PRICE OUR SPECIAL CASH PRICE 485.00 350.00 750.00 625.00 199.00 170.00 13.00 7.00 Imsai 80/15 Kit w/8085 CPU 799.00 625.00 We carry all major lines such as S.D. Systems. Cromemco. IMSAI, Vector Graphic. North Star. Sanyo. ECT. TEI. GorJIioul. Thinker Toys. Hazeltine. IMC For a special cash price telephone us. Subject to Available Quantities • Prices Quoted Include Cash Discounts Shipping & Insurance Extra. Bus. Address. Interface. .S-JQD,inc. 7 White Place Clark, N.J. 07066 201-382-1318 Non-Volatile Memory Board The E4K EAROM Memory Board pro- vides a Multibus compatible nonvolatile memory of up to 4 K words by 8-bit capacity. The memory contents are elec- trically alterable under computer con- trol, permitting it to function as a pro- grammable memory but with the advan- tage of long term unpowered data reten- tion. Either word or block erasure is possible. Operating software listings are provided with the board. Typical appli- cations include remote data acquisition systems, numerical control systems, pro- cess controllers, storage of manually entered constants and telephone number storage. The prices for the E4K EAROM Memory Board start at $420. For further information, contact Schneider Instru- ment Co, 8115 Camargo Rd, Madeira OH 45243. Circle 576 on inquiry card. 218 September 1979 © BYTE Publications lnc Circle 316 on inquiry card. HE MM- 103 DA TA MODEM AND COMMUNICA TIONS ADAPTER FCC APPROVED S-100 bus compatible Both the modem and telephone system interface are FCC approved, accomplishing all the required protective functions with a miniaturized, proprietary protective coupler. WARRANTY One year limited warranty. Ten-day unconditional return privilege. Minimal cost, 24-hour exchange policy for units not in warranty. HIGH QUALITY -50 dBm sensitivity. Autoanswer. Auto originate. Auto dialer with computer-controlled dial rate. 61 to 300 baud (anywhere over the long-distance telephone network), rate selection under computer control. Flexible, soft- ware-controlled, maskable interrupt system. ASSEMBLED & TESTED Not a kit! (FCC registration prohibits kits) LOW PRICE-S359. 95 - Bfi/BSIR, plus shipping & handling Potomac Micro-Magic, Inc Write for brochure: First Lincolnia Bldg., Suite B1 4810 Beauregard St. Alexandria, Va. 22312 Call for further information: VOICE: (703) 750-3727 MODEM: (703) 750-0930 (300 baud) DATA TERMINAL EQUIPMENT FROM MICROMAIL T.I. 810 printer $1,695.°° S0R0C IQ 120 $795.°° • RS 232C, upper/lower case, full ASCII • Numeric keypad, protected fields • Cursor keys plus addressable cur- sor • Auxiliary extension port LA34 DECwriter IV M.199" Upper/lower case, 9x7 dot matrix 10, 12, 13.2, 16.5 characters/inch 2, 3, 4, 6, 8 or 12 lines/inch 22"W x 7"H x 15Vi"D, 25 lbs. 110 or 300 baud, RS 232C serial ASCII Friction feed, paper width to 15" S0R0CIQ 140 * 1,250.°° • RS 232C and 20mA current loop • Extensive editing features • 25th line terminal status display • 16 function keys (32 with shift) New from DIABLO DIABL0 1640 *2,690.°° Receive-only $ 2,331 . 00 High-quality daisywheel printing at 45 cps. DIABLO 1650 5 2,779.°° Receive-only * 2,419.°° Metal daisywheel printing at 40 cps. Includes upper/lower case 150 characters per second RS 232C serial interface Adjustable forms tractor NEC Spinwriter Call or write for prices To Order: Send certified check (personal or company checks require two weeks to clear) including handling* and 6% sales tax if delivered within California. 'Handling: Less than $2,000, add 2%; over $2,000, add 1%. Everything shipped freight collect in factory cartons with manufacturer's warranty. cKHCRQklfllL MICROMAIL • BOX 3297 • SANTA ANA, CA 92703 (714) 731-4338 Circle 223 on inquiry card. BYTE September 1979 219 Circle 227 on inquiry card. Paul McCoy Enterprises, Inc. Software TM NARKLE™ The NAME, ADDRESS, REFERENCE, KEYWORD, LETTER, ENVELOPE SYSTEM. DATA FILE NARKLE ™ is an interactive, menu-operated system that allows the creation, maintenance, up-date, delete, etc, of a mailing information file. Using the 100 reference fields you can store data about each client and also use this data as a means of automatically building smaller more specific files. Also, you can list files, view individual records by name or record number, and so much more. LETTER Using the NARKLE data file and your text editor, NARKLE will create hand- crafted personalized letters completely automatically. It features automatic data file name insertions in the inside address, salutation, and the body of the letter; either first name or title last name. Up to 25 ^keywords" can be used, and so much more. NARKLE is the most polite data system on the market today, easily operated by secretarial personnel with a few hours' instruction. NARKLE is sold on diskettes and includes a 43-page operator's manual. Paul McCoy Enterprises, Inc.™ 300 E. 30th Street, Austin, Texas 78705 Phone: (512) 476-1700 Hardware required for NARKLE and XTABFREQ: 8080 or Z-80 Based Microcomputer/ 48k of memory/CP/M or similar software/CBASIC, Disk drive(s) and interface, terminal and printer. XTABFREQ™ The CROSSTABULATION, FREQUENCY, STATISTICS, ENTRY SYSTEM. XTABFREQ is a completely interactive system which secretarial personnel should be able to operate with only a few hours of instruction. The crosstabulation routine can operate in two or more dimensions, generating cell count, cell row and column %, as well as cell % of total table. The routine delivers Chi-Square, Degrees of Freedom, Lambdas, Uncertainty Coefficients, Etas, Kendall's Tau B and Tau C, Gammas and Somer's D. The SPSS'" user will find XTABFREQ NOT TO BE A COMPROMISE but much more convenient and versitile. FREQUENCY Besides for Absolute Frequency the routine generates Adjusted, Relative and Cumulative Frequency. Also a code and symbol for Weighting can be used with the Raw Count. You also get the Mean, Mode, Kurtosis, Minimum, Maximum, Range, Standard Error, Standard Deviation, Skewness, Median, and Variance. REFENTRY Both the Crosstabulation and the Frequency Routine utilize the very powerful data entry and management routine, REFENTRY™. This routine lets you easily build, examine, store on diskettes, manipulate, and extract files for your XTABFREQ JOBS. XTABFREQ will also accept NARKLE™ File interactively. With XTABFREQ you can predict tomorrow without waiting for punchcards. XTABFREQ is sold on diskettes with a 37-page operator's manual. Send $175 for Narkle and $295 for XTABFREQ. Manuals are available at $10 each. Dealer inquiries welcome. SPSS™ is a copyright of McGraw-Hill, Inc. 220 BYTE September 1979 Circle 291 on inquiry card. Circle 79 on inquiry card. Circle 91 on inquiry card. PET WORD PROCESSOR This program permits composing and printing letters, flyers, advertisements, manuscripts, etc., using the COMMODORE PET and a printer. Script directives include line length, left margin, cen- tering, and skip. Edit commands allow the user to insert lines, delete lines, move lines and paragraphs, change strings, save onto cassette, load from cassette, move up, move down, print and type. The CmC Word Processor Program addresses an RS- 232 printer through a CmC printer adapter. The CmC Word Processor program is available for $29.50. Add $1.00 for postage and handling per order. Order direct or contact your local computer store. CONNECTICUT microCOMPUTER 150POCONO ROAD BROOKFIELD, CONNECTICUT 06804 (203) 775-9659 TLX: 7104560052 NO FRILLS! NO GIMMICKS! JUST GREAT DISCOUNTS MAIL ORDER ONLY HAZELTINE 1400 $679.00 1500 995.00 Mod 1 1495.00 CENTRONICS 779-1 954.00 779-2 995.00 700-2 . 1350.00 761 KSR tractor 1595.00 703 tractor 2195.00 MicroPrinter 395.00 NORTHSTAR Horizon I assembled. . 1629.00 kit 1339.00 Horizon II assembled . 1999.00 kit 1599.00 Disk System 589.00 TELETYPE Mod 43 995.00 DIGITAL SYSTEMS Computer $4345.00 Double Density Dual Drive 2433.00 IMSAI VDP 80/1000 $5895.00 VDP44 4195.00 16K Memory assem.. 399.00 PCS 80/15 679.00 15% oil on all other Imsai products DEC LA34 1149.00 CROMEMCO System III $1000 ott . 4990.00 10% off on all other Cromemco products TEXAS INSTRUMENTS 810 Printer 1595.00 Mosl items in stock for immediate delivery. Factory-fresh, sealed cartons. DATA DISCOUNT CENTER p.o.box-ioo 135-53 Northern Blvd., Flushing, New York 11354, 212/465-6609 N.Y.S. residents add appropriate Sales Tax. Shipping FOB N.Y. I BankAmericard, Master Charge add 3%. COD orders require 25% deposit CP/M ® LOW-COST MICROCOMPUTER SOFTWARE CP/M® OPERATING SYSTEM: • Includes Editor, Assembler, Debugger and Utilities. • Standard version for 8080, Z80, or Intel MDS (other versions available.) • For IBM-compatible floppy discs. • $100-Diskette and Documentation. • $25-Documentation (Set of 6 manuals) only. MAC™ MACRO ASSEMBLER: • Compatible with new Intel macro standard. • Complete guide to macro applications. • $90-Diskette and Manual. SID™ SYMBOLIC DEBUGGER: • Symbolic memory reference. • Built-in assembler/disassembler. • S75-Diskette and Manual. TEX™ TEXT FORMATTER: • Powerful text formatting capabilities. • Text prepared using CP/M Editor. • $75-Diskette and Manual. DESPOOL™: • Background print utility. • Use with CP/M (version 1.4) • $50. Diskette and Manual. 1 DIGJTflL RESEARCH P.O. Box 579 • Pacific Grove, California 93950 (408) 649-3896 ® UNCOMPROMISED QUALITY AND PERFORMANCE IN A JOYSTICK FOR YOUR APPLE II* Available now from your local dealer $65 I or by mail from Whether for technical/graphics or a more realistic game of Star Wars, you' 11 love this precision gimballed joystick with self-centering action and unique capacitive switch that activates with only a touch of the control shaft. Front panel accessible X and Y axis trimmers and input pushbutton are featured on the PAIA/ APPLE n Joystick. Plug compatible with the APPLE II game controller. Distributed by: High Technology, Inc. , Oklahoma City - Dealer Inquiries Invited - Send the PAIA/APPLE/n Joystick Controller □ $65. 00 plus $1. 50 postage enclosed. □ Charge VISA MC Card No. Expiration Date: address, city state zip ELECTRONICS DEPT. 9-8.1020W. WIISHIRE BLVD.. OKLAHOMA CITY, OK 73116 Circle 95 on inquiry card. Circle 297 on inquiry card. BYTE September 1979 221 Circle 93 on inquiry card. Circle 211 on inquiry card. 25 START-AT-HOME COMPUTER BUSINESSES In "Low Capital, Startup Computer Businesses" CONSULTING • PROGRAMMING • MICRO COMPUTER OPPORTUNITIES • SOFTWARE PACKAGES • FREELANCE WRITING • SEMINARS • TAPE/DISC CLEANING • FIELD SERVICE • SYSTEMS HOUSES • LEASING • SUPPLIES • PUBLISHING • HARDWARE DISTRIBUTORS • SALES AGENCIES • USED COMPUTERS • FINDER'S FEES • SCRAP COMPONENTS • AND MORE . Plus — ideas on moonlighting, going full-time, image building, revenue building, bidding, contracts, marketing, professionalism, and more. No career tool like it. Order now — if not completely satisfied, return within 30 days for full immediate refund. • 8% x 11 ringbound • 156 pp. • $20.00 Phone Orders 901-761-9090 ! DATASEARCH incorporated 4954 William Arnold Road, Dept. B, Memphis, TN 38117 Rush my copy of "Low Capital Startup Computer Businesses" at $20. NAME/COMPANY ADDRESS CITY/STATE/ZIP □ Check Enclosed □ VISA □ Master Charge Exp. Date KEYED FILE MANAGEMENT Put data at your fingertips. . .easily accessed, displayed and updated by key. Designed to meet all of your data management needs, MAGSAM'" allows you to quickly implement sophisticated keyed file structures through simple CBASIC statements. Standard MAGSAM'" features include record retrieval with random by key. sequential by key. and generic ("wild card") search, and complete compatibility with all CBASIC file facilities. Each MAGSAM'" Package includes the MAGSAM'" file manager. MAGSAMX'" tutorial program, MAGSAMD'" file dump utility. User Guide, Reference Card, and one year update service. Select the version of MAGSAM'" that meets your requirements. All versions of MAGSAM'" are completely upward compatible and may be upgraded at any time for the price difference. • MAGSAM III™ — Most advanced version. Multiple Key support (any number of keys), and Record and Key Deletion with automatic reclamation of disk space $145t • MAGSAM II'" — Single Key support with full Delete capability S99t • MAGSAM I'" — Entry level version. Single Key support without Delete capability S75t • User Guide only - comprehensive tutorial and reference manual $15 Available for 8" soft sector. Micropolis, and TRS-80 disk formats. Requires CP/M - or derivative and CBASIC. Distributed as CBASIC subroutines in source form. Visa and Masterchagre welcome. Dealer and OEM inquiries invited RflMS) MICRO APPLICATIONS GROUP 7300CALDUS AVENUE VAN NUYS. CA 91406 ' Trademark of Digital Research t Single site license SOFTWARE TOOLS ■ C compilers and cross-compilers for PDP-11 's, LSI-11's, 8080's and Z/80's, with complete runtime library. The full lan- guage is supported with efficient code generation. ■ Interface libraries giving access to all system directives for UNIXf RT-11, RSX-11M, RSTS/E, IAS, CP/M, CDOS and ISIS-II. ■ A-Natural narrative assembler for 8080's and Z/80's with librarian and linking loader. ■ Over 75 installations in less than six months. ^UNIX is a trademark of Bell Laboratories. Continuing maintenance and training available. An affordable alternative to Assembler, Fortran or Pascal, for as little as $500 per compiler binary license. Catalogue and references available upon request. Write to ^ 1x1 whitesmiths, Ltd. 127 East 59th Street -NewYork NY10022- 212 799-1200 WELL, BYTE MA BELL! TRS-80® Software-Level I & II, 4k & 16k Have your TRS-80® computer dial the telephone ■ Dial 20 phone numbers, accessed by a single letter code ■ Operates with dial & pushbutton phones ■ Requires a simple interface using $4 worth of parts from Radio Shack" No internal connections are made to the TRS-80® ■ The program is supplied on cassette tape, with complete instructions ■ (Specify Level I or II with order) TRS-80" is a registered trademark of Tandy Corporation Write to : Software Exchange 2681 Peterboro W. Bloomfield, Mi. 48033 , 222 BYTE September 1979 Circle 388 on inquiry card. Circle 332 on inquiry card. Creative Software Introduces: Programs & Products for the TRS-80 (16K level II) NEW! A supm JOYSTICK interface Un \U TRS-80! Three sockets allow you to use one I am liild" ur Iwo Atari*'" joysticks with no modilu alions to the I'RS-80 Joystick interlace with Iwo Jos/slicks lhain luld'" or Ai $65.00 $12.50 Household Finance I & II $15.00 P. ut 1: Inputs data on each household expenditure: lisis. .ultls. updates, changes or deletes previously input items. Wines data In cassette tape. Part II: Reads data tape. Provides monthly and yearly summaries ol liii.im i.il data, simile < ategury summaries, and graphs .i upending ptolile ALSO: New Programs for the PET: PET Word Processor $75.00 Complete word processing capabilities including uppet lowei case, string search, siring change .aid many other lealures lound on cum menial word processors. Package includes both text editoi and Formatter and requires 16K or H2K PET. PET Space War II $10.00 Fantastic real time action! You .ire in complete control ol the Entet prise as you lend off aliens lo search the universe loi colonizublc planets. Requires the Creative Software single joystick lot the PET. Household Utility 1 $12.00 (Ini'ludfb CiliMulai, Loans and Buy or Rem Programs) Household Utility 2 $12.00 Atnoi li/alion and C Many olhei Creative Software products .ire available lor the PET and TRS-80. II yout local denlei doesn't (any Creative Software products or program inlormation, write directly lo the address below. When placing an order please note: Specilv computet & progtarn(s). Add $1.50 shipping lor each program ordered, $2.50 lor joystick interlace. California residents add 6".. sales lax. VISA MASTKKCI 'AHGH accepted. Include PET Road Race . $10.00 ureauve auuware Another great machine different tracks as you anguuge program gn brattle with your opp /es you a i menl to 1 hiioiioo80»oo»iiiiotmooeaoooao8a80oooooo800Ciie88W8»MlHH»»»»8 »m 1-31 chips 32-63 64-99 100-499 250 nsec. $7.50 6.50 5.75 5.50 450 nsec. $6.50 5.50 4.75 4.50 Circle Inquiry number for free newsletter. h Seattle Computer Products, Inc. 1114 Industry Drive, Seattle, WA. 98188 (206) 575-1830 TRS-80 ... all business! ! ...with CP/M, CBASIC2, & applications software. CP/M Operating System (w/Editor, Assembler, Debugger, Utilities & 6 manual set) $150 CBASIC2 Compiler (w/manual) $ 95 DESP00L Print Spooler (w/manual) $ 75 *Osborne & Assoc. PAYROLL W/C0ST ACCTNG $250 *Osborne & Assoc. ACCTS. RECEIVABLE & ACCTS. PAYABLE $250 *0sborne& Assoc. GENERAL LEDGER $250 *=CBASIC2 source programs; add $15 (each) for applicable O & A book. APH - Self-administered Automated Patient History $175 | DOWNLOAD -TR-80 (or other) CP/M to CP/M $95 data/program (source or object) transfer over RS232 link Send 30ri SASE for add'l. Software avail, (including CP/M Users Group software) and FREE "CP/M Primer." CA residents add 6% tax. Visa, M/C,M/0,Check OK. (714)848-1922 aOdt NEWMAN AVENUE HUNTINGTON BEACH. CALIFORNIA 92647 ffainrcinroT^ North Star* and PASCAL Users: JltUifce's announces Hard disk and 8" drive interfaces to North Star DOS and BASIC and PASCAL TIMESHARING for the Horizon — Interrupt-driven, bank switching timesharing software; supports North Star DOS and BASIC and PASCAL. A complete selection of business applica- tion software is available for North Star* systems. Write or call for descriptive literature. Micro Mike's, Incorporated 905 South Buchanan * Amarillo, Texas 79101 * USA (806) 372-3633 SORCERER* SOFTWARE! FOUR PROGRAMS ON CASSETTES FASTGAMMON™ by Bob Christiansen. Thousands of people are already playing FAST- GAMMON on TRS-80 and Apple. Now it is ready for SORCERER, with the sharpest graphics ever! Backgammon players love this machine language program that provides a skillful opponent. Eight-page instruction manual includes rules of backgammon. $19.95 PLOT by Vic Tolomei. Now Apple owners will be envious of how easy you can get good graphics on your SORCERER. PLOT includes both a super high resolution mode and a quick low resolution mode. Both are accessible from your BASIC programs using simple com- mands. Hi-res & lo-res examples included on tape. 514.95 Z-80 DISASSEMBLER by Vic Tolomei. Decode machine language programs, including SORCERER'S monitor and ROM-PACs, with this Z-80 Disassembler written in BASIC. In- struction mode prints out machine code and Zilog mnemonics in standard format. Or use the ASCII mode which converts machine code to ASCII. $14.95 MAGICMAZE™ by Vic Tolomei. A challenging maze game. Ten levels of play. Holding your lantern, you wander through a maze trying to stay on the right path and avoid pitfalls. Automatic scoring tells you how good a pathfinder you are. $1 1.95 SOFTWARE INTERNALS MANUAL FOR THE SORCERER by Vic Tolomei. A musl for anyone writing software for the SORCERER. Seven chapters: Intro to Machine Language, Devices & Ports, The Monitor, Cassette Interface, BASIC structure, Video & Graphics, The Keyboard. Indexed. Includes diagrams and software rou- tines. 64 pages. 514.95 QUTlLITy SOFTWARE 6660 Reseda Blvd., Suite 103. Reseda, CA. 91335 Telephone 24 hours, seven days a week: (213) 344-6599 WHERE TO GET IT: Ask your nearest Sorcerer dealer to see Quality Software's Sorcerer programs. Or, if you prefer, you may order directly from us. MasterCharge and Visa card- holders may telephone their orders and we will deductSI from orders over S19 to compensate for phone charges. Or mail your order to the address above. California residents add 6% sales tax. Orders outside North America add $5 for registered airmail, pay in U.S. currency. " The name "SORCERER" has been trademarked by Exidy, Inc. 224 BYTE September 1979 Circle 204 on inquiry card. Circle 321 on inquiry card. 10-DAY FREE TRIAL Send for our FREE Catalog Keyboard C Keyboard C Keyboard B Keyboard N Keyboard C Keyboard B Keyboard N 4K 8K 16K 16K 32K 32K 32K C — calculator keyboard (only version with tape deck) B — Large Keyboard (graphics not on keys) N — large keyboard with graphics symbols Used 8K PET with 90-day warranty $650 WE BUY USED PET APPLE and TRS-80 COMPUTERS $100 FREE ACCESSORIES WITH 16K0r 32KPET Terminal Package with 8K PET ACCESSOR Commodore Dual Floppy Disk Drive NEW! T/C 2001 Terminal Package for Second Cassette — from Commodore Commodore PET Service Kit Beeper • Tells when tape is loaded Petunia - Play music from PET $ 595 Video Buffer - Attach another CRT $ 795 Combo - Petunia and Video Buffer $995 Betsi 4-slot S-100 Motherboard $ 995 S-100 PET Interface was $289.00 SALE $1195 New Serial Printer Interlace lor PET . . $1195 Integral Data Printer w new interface $1195 pet - Compatible Seleclric in Desk TTY KSR-33 Screen Printer lor PET Ca u Hazeltine 1400 LIST SALE $1295.00 the PET $69.00 $95.00 $30.00 $24.95 $29.95 $29.95 $49.95 $119.00 $99.00 $79.95 $878.95 $895.00 $395.00 I lor Availability Originate Answerback Modem lor PET Bi-directional RS-232 Interfac Q3X3 CBS31 $320.00 $280.00 apple II 200 FR€€ RCC€SSOfll€S The new Apple II with Applesoft BASIC built-in! Elimi- nates the need lor a $200 Firmware Card and includes new Autostart ROM for easy operation. This combined with the FREE accessories from NCE could save you up to S400 on a 48K Apple II system! 16K Apple II Plus — $11 95 (take $100 in free accessories) 32K Apple II Plus — $1345 (take $150 in free accessories) 48K Apple II Plus — $1 495 (lake $200 in free accessories) Apple II Accessories Centronics Printer Interface Disk and Controller Second Disk Drive Parallel Printer Card Communications Card Hi-Speed Serial Card Firmware Card Hobby Proto Card »22S Call lor Availability. $595 $495 $180 $225 $195 $200 $24 OF THE MONTH Call for Availability Microverter RF Mod $35 Sanyo M2544 Recorder $55 APPLE II PRINTER PACKAGE $995 For this low, low price, we choose a Centronics Impact Printer and match it up with an interlace and cable for your Apple II. You save hundreds of dollars. Limited quantities available. *5Q # New 300 baud Originate Answer Acoustic Coupler. Looks good, works great and sale priced at ^$189 CAT COUPLER ■ Desktop Selectrle-Based - Terminal $319! Super bargain while they last: A desktop terminal based on an IBM Selectric typewriter for only $319 including documentation. These terminals were originally designed for use with timesharing sys- tems where top-quality printing was required. The IBM keyboard and printer are separated by a three foot cable and each has its own enclosure (great for custom installations!. Serial RS-232 interface uses PTTC instead of ASCII codes so you will need to write a conversion program (we have ho ASCII interface for this model). 14.8 cps, 134.5 baud 13" line length, pica. Sold in AS-IS condition, our warranty is limited to replacement of missing parts (we check all motors). IN STOCK NOW EVERY ITEM IN THIS ADVERTISEMENT IS IN STOCK AND READY TO SHIP, EXCEPT WHERE NOTED. SAVE UP TO 43% Whlle ,he * last CENTRONICS PRINTERS Refurbished excellent working condition. 10 day return privilege of course. 90-DAY SPEED WIDTH PRINT WORKING WARRANTY MODEL (Ipm) (col's) MATRIX PRICE PRICE SUPER SALE PRICE TOO LOW TO ADVERTISE Immediate Delivery — 2-Year Factory Warranty You may have seen the Hazeltine advertised at $850. You may have seen it sale prices at $749 or even $699 but our new price is so low that we can t even advertise it. Call us for a quote Hurry, we have a limited quantity at this price The 8048-based Hazeltine 1400 has a 12 screen. 24x80 display. TTY-style keyboard, addressable cursor and RS-232 I O from 110 to 9600 baud Hazeltine 1410 — $835 Adds a 12-key numeric keypad to the 1400 tor financial or mathematical applications. 2-year warranty. Hazeltine 1500 — $1069 Full-capability terminal complete with 12" screen. 24 x 80 display, upper lower case, dual intensity. Hazeltine 1510 — $1195 Additional memory is added to provide buffered data entry operations with editing capabilities Hazeltine 1520 — $1499 Buffered like the 1510 but a microprocessor has been added to offer independent printer control. CRT TERMINAL PRINTER PACKAGE Hazeltine 1520 and a Centronics 761-5 together for only $2,295. The perfect work station for use with a buffered communications system. Terminal operations and print- ing may operate simultaneously. • Refurbished 4> 700 13-90 132 5x7 660 1 075 Character Elonqation 701 25-120 132 5x7 695 1 175 Char Elong Bidirectional 761 60 132 7x7 695 1 025 Teleonnter Bidirectional "Model 761 includes Keyboard NCE/CompuMart SELLING COMPUTERS BY MAIL SINCE 1971 1250 North Main Street, Department BY99 P.O. Box 8610 Ann Arbor, Michigan 48107 (313) 994-3200 ' Member: Computer Dealers Association , Inc. SANYO MONITOR 9-inch 15-Inch -$£40. $169 -$400. $279 SANYO MONITOR when you buy the SORCERER $995 Z-80 Processor • Full-size keyboard • User definable characters • Up to 32K on-board RAM • Interchangeable ROM PACs- 30x64 display -Resident 4k monitor ROM- Dual Cassette I/O • Serial and Parallel I/O ■ Complete operator's manual Simply add a monitor and tape decks to complete the system. Can be used as a terminal Microsoft BASIC ROM PAC is standard. NEW! Exidy Word Processing ROM PAC now available which handles tabs, search, replace, etc., many different printers and can be used with cassette or disk. The most flexible W, P system we've ever seen. Sorcerer 8K $995 Sorcerer 16K $1150 Sorcerer 32K $1395 Word Processing ROM PAC Call lor Availability $99 IMPORTANT ORDERING INFORMATION All orders must include 4% shipping and handling. Michigan residents must also add 4% for state sales tax. All foreign orders (except Canada) need an additional 10% for shipping and handling. We cannot process your order without these. Phones open from 9:00 a.m. to 7:00 p.m. EST Monday-Friday, 10:00 a.m. to 5:00 p.m. Saturdays • P.O.'s accepted from D & B rated companies — ship- ment contingent upon receipt of signed purchase order • All prices subject to change without notice • Most items in stock for immediate shipment — call for delivery quotation • Sorry, no C.O.D.'s • In the Ann Arbor area? Retail store open 1 1:00 a.m. to 7:00 p.m. Tuesday- Friday, 10:00 a.m.to 5:00 p.m. Saturdays (Closed Sunday and Monday) Circle 283 on inquiry card. BYTE September 1979 YOUR #1 SOURCE FOR California Computer Systems Available at HOBBY WORLD Model 2500A S-lOO Wire Wrap Board • 5-100 BUS compatible • Double sided PC board • Plated thru holes • Perimeter ground • All S-100 BUS signals labeled and numbered • Accommodates standard size IC sockets • 4 to-220 regulator positions available • Allows either positive or neg- ative regulators • Dense hole configuration . Cat No. 1600 $ 27.00 Model 2501A S-lOO Solder Board • 5-100 BUS compatible ■ Double sided PC board ■ Plated thru holes • Perimeter ground • All $-100 BUS signals labeled and numbered • Accommodates standard size IC sockets • 4 to-220 regulator positions available • Allows either positive or neg- ative regulators • Dense hole configuration .Cat No. 1604 $ 27.00 [Model2501AS-100l Mother Board • 12 slot capability • All 12 S-100 bus connectors in- cluded • Low inductance inner-conned to reduce signal noise and crosstalk • Active termination of all bus lines to further reduce signal noise and line reflections • Distributed bypassing of all power lines • Solder mask both sides of board • Silkscreen of reference desig- nations • Simple strong hoard mounting • Criss-cross BUS lines both sides of board • All holes plated thru • Solder plated circuit area Cat No. 1616 Kit $ 90.00 l Cat No. 1615 A&T $105.00 . Model 2520A S-lOO Extender/ Terminator • Active and/or dynamic term- ination • All power lines fused (or pro- tection • All S-100 lines labeled and numbered • Can be used as an extender and/or terminator • Solder mask both sides of board Silkscreened reference desig- nations • Gold plated fingers .Cat No. 2520 Kit S 37.95 . Model 7811 A Apple II Arithmetic Processor | • Based on AMD AM9511 de- vice 1 Fixed point 16 and 32 bit op- eration I • Floatingpoint 32 bit operation • Binary data formats • Add, subtract, multiply, and divide I • Trigonometric and inverse tri- gonometric functions I * Square roots, logarithms, ex- ponentiation | * Float to fixed and fixed to float conversions 1 Slack oriented operand stor- age ■ Programmed I/O data transfer • End signal selectable interrupt • Supports interrupt daisy chain • Allows DMA daisy chain • Power down ROM | • 256 bytes firmware (ROM) or software (RAM) space avail- able I Cat No. 1635 $375,00 Model 7114A Apple II Prom Module The 7114A PROM MODULE per- mits the addition or replacement of the Apple II firmware without the physical removal of the Apple II ROMS. This allows soft- ware/firmware replacement, change, and/or patch to be made on a ROM or BYTE BASIS. An on-board enable/disable toggle switch rs also available. • BYTE oriented program over- lay " Selectable prom overlay • Power down of PROMS • 14K PROM space available I • Uses +5 volt 2716 type proms 1 Allows use of DMA/interrupt daisy chains I Cat No. 1631 A&T $ 72.00 L Cat No. 1630 Kit $ 62.00 Model 2016B s-ioo 16K Static Memory • Fully static operation • Uses 2114 type static rams • +8 VDC input at less than 2 amps • Bank select available by bank port and bank byte • Phantom line capability ' Addressable in 4K blocks in 4K increments • 4K blocks can be located any- where within 64K bank • May be used as a 4K, 8K, 12K or 16K memory board • Led indicators for board/bank active indication , • Solder mask on both sides of board ' Silk screen with part and refer- ence designation 1 Available fully assembled and tested, as a kit, or as a bare board | Cat N0.I6OIA Kit 450ns 5285.00 Cat N0.I6OIB Kit 200ns $340.00 1 Cat No. 1602 A A&T 450ns $330.00 LC.1I No.16A2B A&T 200ns $385.00 , Model 7470A Apple II 3 3 A Digit BCD A/D Converter The 7470 allows conversion of a DC voltage to a BCD number for computer monitoring and analy- sis. Typical inputs would be DC inputs from temperature or pres- sure transducers. " Selectable interrupt on end of conversion • 20QUS per conversion • -4 to +4 VDC full scale • Plus or minus .05% nanlinear- ttv • Plus or minus 1 count quanti- zation • Correctible offset error • Temperature coefficient ad- justment • Calibration adjustment • Input offset adjustment • Floating inputs • Overange and sign indicators • Input filter • Power down ROM ■ Supports interrupt daisy chain • Allows DMA daisy chain • 256 byte firmware (ROM) or software (RAM) space avail- able Cat No. 1621 Kit $115.00 LCat No. 1622 A&T $135.00. Model 2200A Mainframe S-100 compatible Industrial/commercial quality construction • Flip-top cover • Excellent cooling capability • 12 slot capability (uses model 2301 A) • Input 105. 115, or 12S VAC • Output +8 VDC, 20A + -16 VDC 4A • Active termination of all bus lines Fan and circuit breaker includ- ed • Rugged construction • All parts available separately Cat No. 1612 Kit $330.00 L Cat No. 1614 A&T $375.00 . Model 7440A Apple II Programmable! Timer Module ■ Flexible external interface patch area for custom inter- face applications • Selectable prescaler on timer 3 capable of 4mhz input • Programmable interrupts • Readable down counter indic- ates counts to go to time-out • Selectable gating for frequen- cy or pulse width comparison • Three asynchronous external clock and gale/trigger inputs internally synchronized • Three maskable outputs to patch area • Power down ROM • Supports interrupt daisy chain • Allows DMA daisy chain • 256 byte firmware (ROM) or software (RAM) space . able Cat No. 1617 Kit $135.00 kCal No. 1618 A&T $145.00 A Apple II Model 771 2A Synchronous Serial Interface • Conforms to RS-232C [config- I uration A thru E) • Supports half or full duplex | operation • DTE type configuration • Failsafe RS-232C operation • 14 STD CLK rates 50-19.2K BAUD plus EXT CLK • BAUD rates dip switch select- able • All BAUD rates crystal con- trolled " Programmable interrupts from transmitter, receive;, and error detection logic • Character SYNC by one or two SYNC codes I • Programmable SYNC code re- gister I * Standard synchronous signal- ing rate per RS-269JANSI X3.1- 1976 Peripheral/modem control functions I • Three bytes of fifo buffering on both transmit and receive date 7,8, or 9 hit transmission I * Optional odd, even, or no par- ity bit I • Parity, overrun, and overflow status checks I " Power down prom I • 256 bytes firmware (ROM) or software (RAM) space avail- able ' I • Supports interrupt daisy chain • Allows DMA daisy chain Leaf No. 1627 Kit $ 90.00 1 Apple II Model 7710A Asynchronous Serial Interface • Parity, overrun, and framing I error check • Optional divide by 16 clock | mode • False start bit detection • Software programmable inter- | rupts • Data double buffered • One or two stop bit operation | • Power down PROM • 256 bytes firmware (ROM) or I software (RAM) space avail- able • Supports interrupt daisy chain • Allows DMA daisy chain • 134.5 BAUD available for sol | eclric interface • Conforms to RS-232C (config- uration A thru E) • Supports half or full duplex operation • OCR type interface • Failsafe RS-232C operation • 14 STD CLK rates 50-19.2K BAUD plus EXT CLK • BAUD rates dip switch selec- table • All BAUD rates crystal con- trolled except EXT • 8 and 9 bit transmission • Optional even, odd, and no parity bit • Programmable control regis- ter Cat No. 1624 A&T $145.00 LCat No. 1623 Kit $ 90.00 A Model 7720A Apple II Parallel Interface Two bi-directional 8 bit buses for interface to peripherals • Tow programmable control registers • Two programmable data dir- ection registers • Four individually controlled interrupt input lines; two use- able as peripheral control out- puts 1 Handshake control logic for input and output peripheral operation 1 High impedance 3 stale and direct transistor drive pheri- pheral lines • Programmable interrupts 1 CMOS drive capability on side A peripheral lines > 2 TTL drive capability on all A and B side buffers I ■ Power down ROM Supports interrupt daisy chain • Allows DMA daisy chain [ • 256 bytes firmware (ROM) or software (RAM) space avail- able I Cat No. 1633 A&T $105.00 I Cat No. 1632 Kit $ 62.00 Model 7500A Apple II Wire Wrap Board I The 750OA is used for the I prototyping or building of uniquel circuits for the Apple II computer. • All bus signals labeled on I board • Perimeter ground • Size: 7 inch long x 2.75 inch I high ■ All holes plated thru • Gold plated conector fingers I Cat No. 1606 $ 19.00 | Model 751 OA Apple II Solder Board The 7510A is the same as the 7500A except it is designed for soldering of circuits- 1 Cat No. 1607 $ 19.00 Model 7590A Apple II Etch Board 1 The 7590A is a (wo sided copper | board which allows the actual etching of circuits for use in the | Apple II computer. I Cat No. 1608 $ 19.00 Model 7520A Apple II Extender Board The 7520A is a handy tool when debugging or testing modules in the Apple II. ifal No. 1611 Kit $ 21.00 J 19511 BUSINESS CENTER DRIVE 226 BYTE September 1979 Circle 170 on inquiry card. A I COMPUTER ELECTRONICS CALL TOLL FREE: (800)-423-5387 CA, HI, AK: (213) 886-9200 SOFTWARE SOFTWARE Star Trek III The most advanced ver- sion we've seen! TRS-80 L2, 16K Cat No. 1041 $14.95 Backgammon You play against the com- puter! With hints on strategy, etc. Extremely good! TRS-80 L2-16K Cat No. 1481 $10.95 Sargon Chess Winner of all tournaments! 6 levels of play, excellent fraphics. RS-80 L2, 16K Cat No. 1093 $19.95 Apple II, 16K Cat No. 1317 $19.93 Tarot Excellent graphics, frigh- teningly accurate! TRS-80 L1/L2 4K Cat No. 1042 $5.95 Air Raid An arcade-type real time fame of target practice, xcellent Graphics TRS-80 L1/L2 4K Cat No. 1186 $14.95 Microchess Graphic Chessboard with 3 levels of play. TRS-80 L1/L2, 4K Cat No. 1182 $19.95 Apple II Cat No. 1183 $19.95 CASSETTES CASSETTES Fortran Plus By Microsoft! For TRS-80 L2 with 32K single and disk. Cat No. 1341 $340 Beat the House 4 Casino games: Black- jack, roulette, craps, slot machine. Excellent simu- lation. TRS-80 L2, 16K Cat No. 1347 $14.95 Apple II, 16K Cat No. 1349 $14.95 Level III Basic Gives your TRS-80 the fiower of a full size sys- em. Disk commands, ad- vanced editing, etc. TRS-80 L2, 16K Cat No. 1332 $49 Bridge Challenger You and dummy play against the computer in regular contract bridge. Either you or comp sets TRS-80 L2, 16K Cat No. 1195 $14.95 Apple 1GK Cat No. 1196 $14.95 Machine Language Monitor | Allows you to interact dir- ectly with the TRS-80 at machine language level. 11pp manual. TRS-80 L1/L2 Cat No. 1048 $23.95 Daily Biorhythm Electric Pencil Plots a 31 day graph cen- tered on the day you compute. TRS-80 L1/2 Cat No. 1051 $5.95 The famous word proces- sor for the TRS-80 L1/L2 16K Cat No. 1338 $95 L2 diskette version Cat No. 1338D $145 VERBATIM 574 Diskettes I $27 box of lO 4 boxes for $1 OO Cat No. Type Us* 1147 Soft sector TRS-80, Apple 1148 Hard, 10 hole North Star 1149 Hard, 16 hole Micropolis 8" Disks $37 box of lO 3 boxes for $100 • IBM compatible • Single density • Individually certified I Cat No. 1145 Type 32-1000 Description 32 sector holes, 1 -index hole ICat No. 1146 Type 34-1000 I interchangeable with IBM32,| I 3740, 3770, 3790, etc. EDGE CONNECTORS • Cold plated Description S-100, Imsai type, Solder- tail Cat No. 1376 Price $4.00 | S-100, Imsai type, wire- wrap Cat No. 1428 Price $4.25 S-100, Altair-type, solder- tail Cat No. 1388 Price $4.00 86-pin Motorola type, wirewrap Cat No.1389 Price $2.50 , from Novation CAT Acoustic Modem • For TRS-80, Apple, etc. Lets your computer talk to other computers over standard telephone lines. Also communicates with any Bell 103 compatible $195 modem. Designed specifi- cally (or small computers! Fully assembled and tes- ted. Cat No. 1480 Anadex Alphanumeric Printer $925 • For TRS-80, Apple, etc. Features 80 columns, 84 lines per minute, super high reliability, 9x7 character font. Completely self contained, perfect for terminals or as a stand alone printer. Prints com- plete 96 character ASCII font. Complete with inter- face for RS232C and 20/60mA current loop mode. Also Centronics plug compatible interface which accepts data in a parallel bit, serial char- acter synchronous form. Programmable baud rate, plus dozens of other fea- tures found only in prin- ters costing twice as much. Cat No. 1342 DP8000 Printer $925 Cat No. 1343 TRS-80 Adapter Cable $40 Cat No. 1456 3000 sheets 1 part paper $31.50 Cat No. 1457 1500 sets 2-part paper $40.50 Cat No. 1458 1000 sets 3-part paper $40.50 RECTIFIERS & BRIDGES Order by Cat No, Voltage, and Current 1A 3A 12A 35A 2A 6A 25A RECT. RECT. RECT. RECT. BRIDGE BRIDGE BRIDGE #1001 #1002 #1391 #1392 #1003 #1004 #1034 50V .05 .12 .36 .80 .30 .50 1.20 1O0V .06 .16 .50 .98 .45 .65 1.50 200V .08 .20 .64 1.15 .60 .80 2.00 400V .10 .24 .78 1.35 - 2.50 600V .12 .30 .98 1.60 800V .14 1.26 1.95 - .10O0V .16 1.54 2.30 SSM Available at HOBBY WORLD |Cat No. 1408 1409 1410 1400 A 1401A 1402 1405 1406 1407 1425 1426 1420 1422 1424 1440 1433 1434 Model Price SB1 kit $150 SB1 a&t $212 SB1 bb $35 MB6B kit 450 ns $139 MB6B a&t $139 450 ns $183 MB6B bb $26 MB7 kit $325 MB7 a&t $370 MB7 bb $26 MB3 kit $54 M83 a&t $108 MB4 kit(2MHz)$80 MB4 a&t (2MHz) $132 MB4 bb $26 PB1 kit w/textool $125 MB8A kit $78 MB8A a&t $125 Cat No. 1435 1436 1437 1429 1430 1431 1427 1428 1403 1417 1418 1419 1438 1439 1414 1415 1416 1411 1412 1413 Model MB8A bb MB9 kit MB9 a&t OB1 kit OBI a&t OB1 bb XB1 Connector for XB1 CB-1 kit VB1B kit VB1B a&t VB1B bb VB2 kit VB2 a&t ■02 kit I02 a&t I02 bb I04 kit I04 a&t I04 bb Price $26 $64 $118 $45 $74 $26 $10 $4 $119 $129 $175 $26 $135 $195 $48 $75 $26 $139 $185 $26 Ribbon Cable CLEARANCE SALE {•Flat style, 28AWC | 'Order by Cat No. 7767 & conductors Cond. 10 ft. 10 $1.00 26 2.60 34 3.40 40 4.00 IC Sockets ' Penny-A-Pin Texas Instruments Solder tail Package quantities only Order by Cat No. 1117 and pins 8 pin 20 for $1.60 14 pin 10 for $1.40 16 pin 10 for $1.60 18 pin 8 for $1.44 20 pin 8 for $1.60 22 pin 8 for $1.76 24 pin 3 for .72 28 pin 3 for .84 40 pin 2 for ,80j /Hatchless Systems - TRS-80 /Minidisk Drive Accesses twice as fast as the Radio Shack drive, plus offers 40 tracks as opposed to 35! Includes | case, power supply, and cables. Completely assem- bled and tested, ready to plug in and go! Simple $395 modification to second drive! Cat No. 1375 MINIDISK DRIVE $395 Cat No. 1396 4 DRIVE EXPANSION CABLE $40 Cat No. 1147 Verbatim Diskettes for above - box of 10 for $27 Send for FREE CATALOG Featuring: The best selection of com- f mtcr accessories add-ons, actory fresh IC's, led's, semi's, software, PC aids, ? prototyping aids, books, est equipment, and more! Always updated! Dozens of new products every J Jssue! r Pay by check, COD, Visa,' or Mastercharge. Order by phone or mail. Mini- mum order $10. Please include phone number and magazine/issue you are ordering from. USA: Add $2 for shipping/handling P round; $3 for air. OREIGN: Add. $3 for surface. $6 for air. COD's $1 add'tl. Guaranteed sat- isfaction for 120 days or your money back! Not re- sponsible for typographical errors. We reserve the l right to limit quantities. Dept. B9 NORTHRIDGE, CA. 91324 Circle 170 on inquiry card. BYTE September 1979 227 POB [AMIIHCAN 1 ■ XPRCBS 1 Electrolabs 6721, Stanford, Co. 94305 ,„ cw/om/ 415-321-5601 //»'„- 800-227-8266 TLX: 345567 FLOPPY SYSTEMS NEW . CATALOGUE Crystals Integrated circuits Keyboards Lasers LSI-11 Media RAMs S-1 00 Components Z-80 Components 8" Siemens FDD 120-8 Drive All. Siemen's options included in this drive which can be con- figured hard or soft and single or double density. (Others give only stripped unit) $399.00 "Power One" Model CP206 Floppy Power Unit For two drives going full-out, and poss- ip ably more on less severe service. Wf§ 2.8A@>24V, 2.5A@5V, 0.5A@-5V. t J Beautiful quality. $99.00 DISKETTES (Standard) <^ 8" SV" Boxed 10 Boxed 10 539.00 534.95 *^~. Tarbell ("It Works") Interface (Includes cable set for 2 drives) $265.00 BUT ONLY $219.00 with purchase of two drives. Cable Kits 10' with 50 cond. cable and connectors and also Molex connectors and power cable: For one drive: $27.50 For two drives: $33.95, and for three drives: $38.95 CABINETS for FOD120 and 801 R Drives, or CP206 power supply. Matte finish in mar resistant black epoxy paint. ng type design. $29.99 ELECTRO LABS is proud to announce appointment as DISTRIBUTOR by CI I- Honeywell Bull. PRICE BREAKTHROUGH on SUPERDJSK 10MBY! $3495.00 General purpose controller (requires 2 parallel I/O ports) 1 500.00 S- 100 Controller (DMA) 995.00 "RL-01/RK-05" surrogate 1900.00 (transparent to RT, RS, RX) SOFTWARE: (CP/M Compatible) SUPERD0S1 (Z-80) $695.00 ^ MICR0D0S1 (TRS-80)... $199.00 Power supply (switching) jL $395.00 Enclosure (desktop) "~"1, ". £ 99 00 * aa,uu Removeable Media Cartridge Drive Hi Used Sylvania 12" Video Moni- tors. Composite video 15mhz, 115vac, 50/60hz New Tube. As shown $109 OEM style without case: $99, Anti-glare tube option add $12. Specify p4 or p39 ESAT 200B BI-LINGUAL 80x24 COMMUNICATING TERMINAL Scrolling, full cursor, bell, 8x8 metrix, 110-19,200 baud. Dual Font Appli- cations. Arabic & Hebrew, Multilingual Data Entry, 5%" MINI-FLOPPY DRIVE $299.00 - single or double dens- ity - quick access time - high reliability & durability Mini-floppy CABLE KIT: for TRS-80 or your Tarbell controller. $24.95 Daisy Wheel Printers Qume Sprint: 3\45 Print wheels $8.95 Ribbons $5.95 OEM Style mechanism $1399.00 Forms Drawing, Music Instruction, Specialized Graphics (e.g. Games, Chemical Plants, Switchyards) $349.00 We carry keyboards, cases, power supplies, etc., enough to make an entire system. 228 BYTE September 1979 Circle 115 on inquiry card. The TO ORDER CALL TOLL FREE 800-223-7318 • 16-bit microprocessor • 16K RAM • 13" color monitor (24 lines of 32 chrs.) • 26K BOM opereting system (Includes 14K BASIC) • Sound - 3 tones. 5 octaves • 16 colors: 192 x 256 res. • Large Tl library of ROM programs available. Includes 13"l olor Monitor!! only FINALLY k — — 1$1150 TEXAS \H»^ INSTRUMENTSTI-99/4 Home Computer Many Peripherals. Coming soon! APPLE II PLUS ONLY$1195 A complete sell-contained computer system with APPLESOFT floating point BASIC in ROM. lull ASC 1 1 keyboard in a light weight molded carrying case. Features Include: • auto-start ROM • Hi-Res graphics and 15 color video output. • Expandable to 48K. Disk $595 Programmer's Aid 50 Add-on Disk 495 Speechlab 229 Pascal Card 495 Lightpen 250 Business Software 625 Communication Card 225 Monitor 149 Modem 200 PnnterCard 180 EPROM Programmer 100 NEW D. C. Hayes MICROMODEM II • Combines the capabilities of a communications card and acoustic coupler. • Plugs directly into Apple slot and modular telephone Jack. *o^n • Auto dial/receiver* FCC approved Only* $379 NEW Mountain Hardware SUPERTALKER • Digitized speech recording and playback. • Must be heard to be believed! • Foreign language teaching pack available. • Software compatible. only $279 SUPRBRAIN TM INTE3TEC DATA SYSTEMS ONLY $2995 d:: : m on iv $795 • 14K ROM Operating system • 8K RAM Memory • 9" Video Monitor • Built in Keyboard • Digitally controlled tape S1 495 Complete! 16K Model add $200 32K Model add $500 PET More than an intelligent terminal, the SuperBrain outperforms many other systems costing three to five times as much. Endowed with a helty amount of available software (BASIC, FORTRAN, COBOL), the SuperBrain is ready to take on your toughest assignment. You name it! General Ledger, Accounts Receivable, Payroll, Inventory or Word Processing. . .the SuperBrain handles all of them with ease. Features Include: • two dual-density minifloppies with 320K bytes of disk storage • 64K of RAM to handle even the most sophisticated programs • a CP/M Disk Operating System with a high-powered text editor, assembler and debugger. FREE $35 of Software with purchase of any computer on this page. COMPUCOLOR II Disk-Based Model 3 Advanced hardware and software technology gives you • 13' Color Display • Advanced Color Graphics • 51K Disk Built-in • 16K ROM Operating System • 8K RAM User Memory • 4K RAM Refresh • 8080A Microcomputer • RS-232 I/O |^t SPECIAL SPECIAL $200 FREE Software with,Jy| purchase of 8K PET >* | Over 1000 software tapes, books, disks on display. Come in and brouse. JM Xacc V Wf Data General BUSINESS COMPUTER IMSAI The low cbsl solution lor all small business problems A wide varn of software is available lor ail your needs PCS series include dual llopp.es. 32K RAM. I O. DOS. BASIC • PCS-42 (400KB) $3295 • PCS-44 (780KB) $3995 VDP-42 series adds video terminal, key- board and VIO to above • VDP-42 $4995 • VDP-44 $5595 • VOP 80 $7995 • VDP 180 $8995 10 Megabyte System $17,040 DATA GENERAL ^ micro NOVA The ultimate in small Business Computers when matched with COMPUTER FACTORY'S inicomputer. Software: Accounts Receivable/Payable, Inventory Control/ Order Entry. Genreal Ledger, Payroll Systems. . . . from $12,140 for 64K computer with cabinet, printer terminal, video terminal. dual disk and mutll-user operating system! SOUNDWARE MUSIC BOX only $29.95 Music and Sound Effects for PET, TRS-80. & Compucolor ll Add music and sound effects to your programs. Compose, play, and hear music on your computer. Completely self-contained. Free programs. This fantastic program disk allows the statistician, Moving mathematician, trader in stocks, money or Average commodities, the ability to maintain 30 database Plot series of up to 300 values and plot 3 different moving Program averages of a series at the same time, in 3 different FOR colors. Files can be updated, deleted, changed, APPLE extended, etc. A sure value disk at only $40! Word Processing For Apple on disk.. .$50 ■ £4 User Defined Cher • 240 » SI? Resolution Grai Module! dtugn al lor program* end RDM PAC luture language i COBOL. PILOT. FORTRAN. 8KS 995 16K$1145 32K $1295 48K $1445 SORCERER SPECIAL 12 Video Monitor > for SORCERER ($299 value) ONLY 125 with 8K unit 95 with 16K unit 65 with 32K unit ANDERSON JAC0BS0N S41 1/0 Terminal Ideal (or word procei mg end imall bun • ASC 11 Code • 15 cot Printout • High Quality Selective Printing • Use Keyboard tot PET • Retiebte heavy duty Mechanum • Completely Refurbished by A.J. • Service in 15 Major CitiM foCKII NOW IN s Parallel $1095 $1195 RADIO SHACK • PET • SORCERER |APPLE • COMPUCOLOR • ETC. PRINTERS • PRINTERS • PRINTERS The COMPUTER FACTORY'S extensive CENTRONICS 779 $ 945 inventory and wide seler.lion of computer TRENDCOM 100 375 printers assures you of finding the printer TRENDCOM 200 N/A best suited for your needs and INTEGRAL DATA 795 specifications The following printers work DIABLO/XEROX 2695 well with all known personal computers COMPRINT 560 Min Credit Card Order $75 VISA* Open Mon.-Fri. 10-6 NY restdnnis add 8°'6 sales lax • Same day Cat 1fl A shipment on prepaid and credit card orders ***"■ I"-** • Add S5 shipping lot computers. $3 for boards. $1 each cassette fape. NEW CENTRONICS 730 50 CPS ■ MICROPROCESSOR CONTROLLED! Tractor & Friction Feed • Uses Single Sheets, Roll, Fanfold • Upper & Lower Case • Light Weight Parallel $995 Serial $1045 «&>*£& TO ORDER CALL TOLL FREE 800-223-7318 vH» o^ iW TLft fVMUIDI ITCD CAPTHDV 485 Lexinqton Avenue 750 Third Avenue Mew York. N.Y. 10017 I lit? V-fWlVIn U I Cn TMV^ I \JT\ I (212) 687-5001 (212) PET-2OOI Foreign order desk ■ Telex 640U55 BYTE September 1979 229 computer products, inc. 11542-1 KNOTT STREET GARDEN GROVE, CALIFORNIA 92641 (714) 891-2663 MICROBYTE Z80/I-O • A complete single board Z60A CPU and serlal/paralle I/O system • Fully S-100 Bus compatible, IMSAI, ALTAIR • Z80A CPU (4 MHz version of the 280) • 158 Instructions — superset of and upward compatible from the 8080's 78 Instructions • Provision for up to 4K on board monitor program using 1K (2708), 2K {2716), 4K 2732 • On board EPROM can be hard- ware and/or software deselected • 2 MHz or 4 MHz operation is switch selectable • or 1 wait state for all cycles is switch selectable • 2 RS-232C serial ports with 8251 USARTs • Serial baud rates switch selectable • 24 programmable parallel I/O lines (uses 8255) Gold Contacts for higher relia- bility Power requirements: + 8V ® 800mA, + 16V, @ B6mA, - 16V @ 100mA X" rating temperature 0*-55"C operate with or without IMSAI/ALTAIR front panel ' Low power shottky tri-state buf- fers on all address and data lines 1 Fully warranted for 120 days from date of shipment $325. ( IMSAI CONN. 100 PIN-SOLDERTAIL GOLD CONTACTS $3. 00 each or 10/2.60 each 8251 PROGRAMMABLE/U-ART TESTED® 4 MHZ $5. 00 each TRS-80 Floppy disk drive with cabinet & pwr. supply compatible with Radio Shack Interface. Ass- embled & tested with 1 yr. warranty on parts & labor. Mfg. by Lobo Drive $385 Interface Cable Available SPECIAL .1 @ 12 VOLTS CERAMIC CAP 10$ each or 100/$9. 00 MICROBYTE 16K STATIC RAM BOARD Fully S100 Bus Compatible, IMSAI, SOL, ALTAIR, ALPHA MICRO Uses National's Low Power 5257 4K x 1 Static Rams 2 MHz or 4 MHz operation On board single 5 amp regulator Thermally designed heat sink (board operating temperature a - 70*C) Inputs fully low power Shottky Schmitt Trigger buffered on all address and data lines 1 Phantom Is jumper selectable to pin 67 Each 4K bank addressable to any 4K slot with in a 64K boundary. 4K hardware or software select- able < Selectable port address 4K banks can be selected or dis- abled on power on clear or reset Will operate with or without front panel Compatible with ALPHA MICRO, with extended memory manage- ment for selection beyond 64K No DMA restriction Low power consumption 1.3 amp Fully warranted for 120 days from date of shipment Extended addressing up to 1 megabyte of addressable ram 450 NS $320.°° 300 NS $340. 00 MICROBYTE 32K STATIC RAM BOARD • Fully S1O0 Bus Compatible, IMSAI, SOL, ALTAIR, ALPHA MICRO • Uses National's Low Power 5257 4K x 1 Static Rams • 2 MHz or 4 MHz operation • On board single 5 amp regulator • Thermally designed heat sink (board operating temperature 0* - 70"C) • Inputs fully low power Shottky Schmitt Trigger buffered on all address and data lines • Phantom Is Jumper selectable to pin 67 • Each 4K bank addressable to any 4K slot with In a 64K boundary. • 4K hardware or software select- able • One on board 8-bit output port enables or disables the 32K In 4K blocks • Selectable port address • 4K banks can be selected or dis- abled on power on clear or reset • Will operate with or without front panel • Compatible with ALPHA MICRO, with extended memory manage- ment tor selection beyond 64K • No DMA restriction > Low power consumption 2.3 — 2.5 amps • Fully warranted for 120 days from date of shipment. Extended addressing up to 1 megabyte ol addressable ram 450NS$620. 00 300NSS650. 00 MICROBYTE MOTHERBOARD • Extra wide ground plane • Silk screen and solder mask • Assembled and tested > Active Diode termination > Slot for IMSAI front panel • Terminal block connection for easy hook-up 9 slot kit $70. 00 A&T$100. 00 20 slot kit$125. 00 A&T$155. 00 Bare Board 9slot$30. 00 20 slot $50.°° MICROBYTE DISK CONTROLLER • IBM 3740 Soft Sectored 'Compat- ible • Z80 or 8080 compatible on S-100 Bus • Single density runs both mini and full size drives, runs CPM, on Shugart, Perscl, Memorex etc. • Selectable port/address • On board 2708/2716 for bootstrap or monitor program • No hardware jumpers, uses plug in modules for different drives • Uses 1771 B-Qt controller chip • Assembled and tested • Specify disk drive used when ordering by mail $225.° SHUGART 801-Disk Drive WITH CABINET & POWER SUPPLY ASSEMBLED & TESTED 1 YR PARTS & LABOR Mfg, by Lobo Drive $585. 00 Dual Cabinet & Drives Available 2708's LOW POWER 450 NS. $8. 75 each 8for$66. 00 SHUGART SA400 DISK DRIVE INCLUDES CABINET. NO PWR SUPPLY, CUTOUTS FOR SWITCH, FUSE, & INTERFACE CABLE Mlg. by Lobo Drive 00 2716 5 VOLT ONLY LOW POWER 450 ns $325. $40. 00 SCANBE/RN SOCKETS -LO PROFILE (tin) 1-24 25-99 100-499 500 up REGULATORS 14 PIN .16 .15 .14 .12 16 PIN .17 .16 .15 .14 18 PIN .20 .19 .18 .16 20 PIN .29 .28 .26 .25 24 PIN .34 .32 .30 .28 40 PIN .60 .58 .56 .52 1-9 10-49 50UD 320 T- 5 320T-12 340 T5 340 T- 12 78H05 1.25 1.00 .75 .75 6.00 1.15 .90 .70 70 5.70 1.05 .85 .65 65 5.40 NEW PRODUCTS 8086 — CPU BOARD 8088 — CPU BOARD Double Density Controller CALL OR WRITE FOR DEALER INFO CABLE ASSEMBLY for 8" disk drives (2) 50 PIN CARD - EDGE CONNECTORS ON 4ft. RIBBON CABLE $20. 00 ea. extra conn. $7. 00 ea. ORDERING INFORMATION: Name, Address, Phone Ship by: UPS or P.P. Shipping Charge: Add $2.50 up to 5 lbs., all excess shipping charges will be refunded. Credit cards will be charged appropriate freight. TERMS: We accept cash, check, money orders, Visa, and Master Charge cards. (U.S. Funds Only). COD's: on approval only Open Acct's: companies may inquire for net terms. Tax: add 6% for Calif, residents only 230 BYTE September 1979 Circle 11 on inquiry card. Circle 230 on inquiry card. wmam California computer systems 16K RAM BOARD. Fully buffered addressable in 4K blocks. IEEE standard for bank addressing 21 14's PCBD $26.95 Kil 450NSEC $259.95 PT-1 PROTO BOARD. Over 2,600 holes 4" regu- lators. All S-100 buss functions labeled, gold fingers. PCBD $25 95 PT-2 PROTO BOARD. Similar to PT-1 except set- up to handle solder tail sockets. PCBD $25.95 sSffl FORMERLY CYBERCOM/SOUD STATE MUSIC. PB-1 2708&2716 Programming Board with provisions for 4K or 8K EPROM. No external supplies require textool sockets. Kit $124.95 CB-1 8080 Processor Board. 2K of PROM 256 BYTE RAM power on/rest Vector Jump Parallel port with status Kil $119.00 PCBD $30.95 MB-6B Basic 8KX8 ram uses 2102 type rams, S-100 buss. Kit 450 NSEC ...$139.95 PCBD $26.95 MB-7 16KX8, Static RAM uses U.P410 Protection, fully buffered Kit $299.95 MB-8A 2708 EROM Board, S-100, 8K8X or 16Kx8 kit without PROMS $75.00 PCBD $28.95 MB-9 4KX8 RAM/PROM Board uses 2112 RAMS or 82S129 PROM kit without RAMS or PROMS $72.00 IO-2 S-100 8 bit parallel /IO port, % of boards is for kludging. Kit $46.00 PCBD $26.95 IO-4 Two serial I/O ports with full handshaking 20/60 ma current loop: Two parallel I/O ports. Kit $130.00 PCBD $26.95 VB-1B 64 x 16 video board, upper lower case Greek, composite and parallel video with software, S-100. Kit $125.00 PCBD $26.95 Altair Compatible Mother Board, 11 x 11 Vi x Vt" . Board only $39.95. With 15 connectors $94.95 Extended Board full size. Board only $ 9.49 With connector $13.45 SP-1 Synthesizer Board S-100 PCBD $42.95 KIT $135.95 W7nC // ne WAMECO INC. FDC-1 FLOPPY CONTROLLER BOARD will drive shugart, pertek, remic 5" & 8" drives up to 8 drives, on board PROM with power boot up, will operate with CPM (not included). PCBD $42.95 FPB-1 Front Panel, IMSAI size, hex displays. Byte, or instruction single step. PCBD .-. $47.50 MEM-1 8KX8 fully buffered, S-100, uses 2102 type rams. PCBD $25.95 QM-12 MOTHER BOARD, 13 slot, terminated, S-100 board only $34.95 CPU-1 8080A Processor board S-100 with 8 level vector interrupt PCBD $26.95 RTC-1 Realtime clock board. Two independent in- terrupts. Software programmable. PCBD $23.95 EPM-1 1702A 4K Eprom card PCBD $25.95 EPM-2 2708/2716 16K/32K EPROM CARD PCBD $25.95 QM-9 MOTHER BOARD, Short Version of QM-12. 9 Slots PCBD $30.95 MEM-2 16K x 8 Fully Buffered 2114 Board PCBD $26.95 80B0A $9.95 8212 2.49 8214 4.49 8224 3.49 2708 9.49 5101-1P 6.90 5101-8P $ 8.40 2114 (450 NS) lowpwr ... 7.25 2114 (250 NS) lowpwr... 7.99 2102A-2L 1.50 2102A-4L 1.20 4116 8/89.95 M (415) 592-1800 P. O. Box 424 • San Carlos, California 94070 Please send for IC, Xistor and Computer parts list SEPT SPECIAL SALE ON PREPAID ORDERS (charge cards not included on this offer) 8KX8 RAM Fully buffered 450 NSEC. 2.5 amp typical assembled parts may be unmarked or house numbered. $99.99 MIKOS PARTS ASSORTMENT WITH WAMECO AND CYBERCOM PCBDS MEM-2 with MIKOS ~7 16K ram with L2114 450 NSEC $249.95 MEM-2 with MIKOS =13 16K ram with L2114 250 NSEC $279.95 MEM-1 with MIKOS #1 450 NSEC 8K RAM $119.95 CPU-1 with MIKOS #2 8080A CPU $94.95 MEM-1 with MIKOS #3 250 NSEC 8K RAM $144.95 QM-12 with MIKOS #4 13 slot mother board $89.95 RTC-1 with MIKOS #5 real time clock $54.95 EMP-1 with MIKOS #10 4K 1702 less EPROMS $49.95 EPM-2 with MIKOS #11 16-32K EPROMS less EPROMS $59.95 QM-9 with MIKOS #12 9 slot mother board $79.95 FPB-1 with MIKOS =14 all parts for front panel $134.95 MIKOS PARTS ASSORTMENTS ARE ALL FACTORY PRIME PARTS. KITS INCLUDE ALL PARTS LISTED AS REQUIRED FOR THE COMPLETE KIT LESS PARTS LISTED. ALL SOCKETS INCLUDED. VISA or MASTERCHARGE. Send account number, interbank number, expiration date and sign your order. Approx. postage will be added. Check or money order will be sent post paid in U.S. If you are not a regular customer, please use charge, cashier's check or postal money order. Otherwise there will be a two-week delay for checks to clear. Calif, residents add 6% tax. Money back 30 day guarantee. We cannot accept re- turned IC's thai have been soldered to. Prices subject to change without notice. $10 minimum order. $1.50 service charg* on orders less than $10.00. W03 4007 ■ 4000 - C/MOS (DIODE CLAMPED) 4033 - 22 4069 - .45 4024 - 4026 - 4017 - 4028 - 4079 - 4030 - 4036 - 4D72 - 451 a - 4520 - 4042 4063 - 40GS - 4066 - 74C02 - 74C08- 74C1Q- 74C20- 74C42- 74C73- 70 74C90- 74C15I - 74C157 - 74C160 - 74C16S - 74C173 - 74CI74 - 74CI75- 74CI03- 74C901 - 74C90! - 74C914 - 3623 STATIC SHIP IS-3409 Wl BO BITS □YN.5I' 1.9S B3E23 - 17 95 BJSIZ9 US AY61013 VAHT - 35« TR1 «HB - M B703CTELEDYNEB 3*5 n l«B3 fl PSAT - 1.95 90S0A - 2 *5 BZ ,b _ -CRYSTALS $3.45 •« 2.000 MHz 6.144 MHz 4.000 MHt. 8.000 MHz 3.57 MHz 10.000 MHz 5.000 MHz 20.000 MHz 6.000 MHz RIBBON CABLE PLAT (COLOR CODED) #30 WIRE 26 cond. - .S0/per foot 40 cond. ■ ,75/pcr foot 50 cond. • .90/oor foot CTS 206-8 eight position dip switch $1.60 CTS 206-4 four position dip switch $1.45 LIGHT ACTIVATED SCR's to 18. 200 ,V 1A. .$.70 SILICON SOLAR CELLS 4" diameter .4V at 1 AMP $10.00 FND 359 C.C.. 4" $.60 LED READOUTS FCS8024 4 digit DL-704 C.A. .3" $ .75 C.C 8" display 55.95 DL 747 C.A. 6" $150 FND503C.C. .5" S .85 HP3400 .8"CC $1.95 FND 510 C.A. .5"$ .85 HP3405 ,8"CA $1.95 DL 704 .3" C.C. S 85 PRINTED CIRCUIT BOARD 7WATTLD 65 LASER DIODE I R Sa95 2N 3820 P FET S 45 2N 5457 N FET $ 45 2N2646.UJT S .45 ER 900 TRIGGER DIODES 4 SI 00 ?N G028 PROG UJT 5 65 MINIATURE MULTI-TURN TRIM POTS 100, 1K, 2K, 5K, 10K. 20K, 50K, 200K, 1Mcrj, 2Mcg, 5.75 each 3/S2.00 25 watt Infra Red Pulse I SG 2006 Bquiv. ) Laser Diode (Spec sheet included) S24.95 V E RIPAX PC BOARD $ 12.95 Our new Prototyping is a hi density 4M" x 6V1" single sided 1/16" epoxy board. It will hold 40, 24, 16 (34 units). 14 + 8 pin IC's. There are three busses, + 5V, ground and a Moating buss. There is a pad for a TO-220 regulator. There is a 22 pin edge connector with . 1 56" spacing. FP 100 PHOTO TRANS S .50 RED, YELLOW, GREEN LARGE LED's. 2" 6/$l .00 TIL-118 0PTO-ISOLATOR $.75 MCT-6 OPTO ISOLATOR S .80 1 WATT ZENERS: 3,3, 4.7, 5.1, 5.6, 9.1, 10, 12, 15, 18, or 22V 6/41.00 MCM 6571A 7x9 character gen . . S 10.75 , UNIVERSAL 4Kx8 MEMORY BOARD KIT $69.95 32-2102-1 fully buffered, 1G address linos, on board decoding for any 4 of 64 pages, standard 44 pin buss, may be used with F-8 & KIM Silicon Power Rectifiers 10.50 16.50 1 7 50 20.00 SAD 1024 a REDJCON 1024 sioge a IN 4148 SOLOERTAIL STAHDAHD (TIN) «P*"LP ra 2B pin ST t .99 36 pin ST 1.39 40 pin ST 1.59 SOLOERTAIL STANDARD (GOLD) 2* pin SG S -70 25-49 50-100 28 pin SG 36 pin SG 40 pin SG 1.65 WIRE WRAP SOCKETS (GOLD) LEVEL #3 22 pin WW $ 95 24 pin WW 1 05 28 pin WW 1.40 36 pin WW 159 40 pin WW 1 75 1/4 WATT RESISTOR ASSORTMENTS - 5% 10 OHM 27 OHM 63 OHM I? OHM 15 OHM J3 OHM 39 OHM 8? OHM 100 OHM 18 OHM 47 OHM ?0OHM 22 OHM 56 OHM 50 OHM IBOOHM 220 OHM ,'70 OHM 330 OHM 390 OHM 4 70 OHM 560 OHM 680 OHM 820 OHM 220K 560K I 5M 3.9M 100K 270K 120X 330K 8?0K ASST. BR Includes Resistor Assortments 1-7 (350 PCS.) SO PCS $1.75 50 PCS 1.75 SO PCS 1.75 SO PCS 1.75 SO PCS 1.75 SO PCS 1.75 so pes 1.75 $9.95 ea. $10.00 Min. Order - U.S. Fundi Only Spflc Sheets - 25t! Calif. Residents Add 6% Seles Tex 1979 Catalog Available - Send 4U stamp Postage -Add 5% piusSI Insurance lif desired I PHONE ORDERS WELCOME (415) 592-8097 MAIL ORDER ELECTRONICS - WORLDWIDE 1021 HOWARD AVENUE. SAN CARLOS. CA 94070 ADVERTISED PRICES GOOD THRU SEPTEMBER AV-5-9100 AV-5-9200 AY-5-9500 AY-5-237S HD0165 74C922 TELEPHONE/KEYBOARD CHIPS Push Button Telephone Dialler Repertory Dialler CMOS Clock Generator Keyboard encoder (86 keys) Keyboard Encoder (16 keys) Keyboard Encoder (16 keys) SU.95 14.95 4.95 14.95 7.95 5.95 ICM7045 ICM7205 ICM7207 ICM7208 ICM7209 ICM CHIPS CMOS Precision Timer CMOS LED Stopwatch/Timer Oscillator Controller Seven Decade Counter Clock Generator 24.95 19.95 7.50 19.95 6.95 NMOS READ ONLY MEMORIES MCM6571 128 X9X 7 ASCII Shitted Willi Greek 13.50 MCM6574 126 X 9 X 7 Math Symbol s Pictures 13.50 MCM6575 128 X 9 X 7 Alphanumeric Control 13.50 Character Generator MISCELLANEOUS TL074CN Quad Low Noise bi-let Op Amp TL494CN Switching Regulator TL496CP Single Switching Regulator 11C90 Divide 10/11 Prescalnr 95H90 Hi-Speed Divide 10/11 Prescaler 4N33 Photo-Darlington Opto-lsolalor MK50240 Top Octave Freq. Generator OS0026CH 5Mhz 2-phase MOS clock driver 111.308 .27" red num. display w/integ. logic chip MM5320 TV Camera Sync. Generator MM5330 4K Digit 0PM Logic Block ISpecisll LD110/111 3Vj Digit A/D Convener Set 2.49 4.49 1.75 19.95 11.95 3.95 17.50 3.75 10.50 14.95 3.95 25.00/set LITRONIX ISO-LIT 1 Photo Transistor Oplo-lsolator (Same as MCT 2 or 4N25) 2/990 SN 76477 SOUND GENERATOR Generates Complex Sounds Low Power - Programmable 3.95 each TV GAME CHIP AND CRYSTAL AY-3-8500-1 and 2.01 MHZ Crystal (Chip & Crystal - nc . includes score display, 6 games and select angles, etc 7.95/SBl XR205 XR210 XR215 XR320 XR-L555 XR555 XR556 XR567CP XR567CT XR1310P 1.30 XR1468CN 3 85 XR1488 1.39 1.39 S8 40 4.40 4.40 1.S5 1.50 1.25 EXAR JE2206KA 14.95 JE2206KB 19.95 XR1800 3.20 XR2206 4.40 XR2207 3.85 XR2208 5.20 XR2209 1.75 XR2211 5.25 XR2212 4.35 XR2240 3.45 XB2556 XR2567 XR3403 XR4I36 XR4151 XR4194 XR4202 XR4212 XR4558 XR4739 XR4741 320 299 1.25 1 25 2 85 4.93 360 2 05 .75 1.15 1.47 TYPE IN746 1N7S1 IN752 IN753 1N7S4 IN757 1N7S9 1N9S9 1N965 1 NS232 IN5234 IN5235 1N5236 1N52*2 IW5245 1N456 1N4S8 1N485A 1N4001 DIODES VOLTS W 3.3 400m 5.1 400m 66 4Q0m 6.2 400m 6.8 400m 9.0 400m 12.0 400m 8.2 400m 15 400m 5.6 500m 6.2 500m 6.8 500m 7.5 500m 12 500m IS 500m PRICE 4/1 00 4/1.00 180 10m 50PIV 1 AMP 6/1 00 6/1.00 5/1.00 12/1.00 TYPE 1N4002 1N4003 1N4004 1N40O5 1N4006 1N4007 1N360O 1N4148 1N4154 1N4305 1N4734 1N4735 1N4736 1H473B 1N4742 1N4744 1N1183 1N1184 INI 165 1N1186 1N11B8 VOLTS W 100 PIV 1 AMP 200 PIV 1 AMP 400 PIV t AMP 600 PIV 1 AMP 800 PIV 1 AMP 1000 PIV 1 AMP 50 200m 75 10m 35 10m PRICE 12/1.00 12/1.00 12/1 00 10/1 00 10/1.00 10/1 00 6/1.00 15/1.1 12 1w IS 1w 50 PIV 35 AMP 100 PIV 35 AMP 150 PIV 35 AMP 200 PIV 35 AMP 400 PIV 35 AMP SCR AND FW BRIDGE RECTIFIERS C360 15A ru 400V SCH{2N1W9) C38M 3SA (a 600V SCfl 2N2328 1.6A@ 300V SCR MOA 980-1 12A (rf 50V FW BRIDGE REC. MDA9B0-3 12AiTi 200V FW BRIDGE REC C106B1 MPSA05 MPSA06 TIS97 TIS98 40409 40410 40673 2N918 2N2219A 2N2221A 2N2222A PN2222 Plastic 2N2369 2N2369A MPS2369 2N24B4 2N2906 2N2907 PN2907 PlasKc 2N2925 MJE2955 2N3053 .50 .30 5/1.00 6/1 .DO 6/1.00 5/1.00 7/1-00 5.- 1 00 4/1.00 5/1.00 4/1.00 4/1.00 5/1.00 7/1 .00 5/1.00 Transistors 2N3055 MJE3055 2N3392 2N3398 PN3567 PN3568 PN3569 MPS3638A MPS3702 2N3704 MPS3704 2N3705 MPS3705 2N3706 MPS370S 2N3707 2N3711 2N3724A 2N3725A 2N3772 2N3823 2N3903 CAPACITOR 5/1.00 5/1.00 3/1.00 4/1.00 4/1.00 5/1.00 5/1.00 5/1.00 5/1.00 5/1.00 5/1.00 5/100 5/1.00 5/1 00 5/1 00 65 ^U30_ 2N3904 2N3905 2N3906 2N4013 2N4123 PN4249 PN4250 2N4400 2N4401 2N4402 2N4403 2N4409 2N5086 2N5087 2N5088 2N5089 2N5129 PN5134 PN5138 2NS139 2N5210 2N5449 Si 6/100 4/1 00 4/1.00 4/1.00 4/100 4/1.00 4/1 00 5/1-00 4/100 4/1 00 4/1.00 4/1.00 10 pi 22 pi 47 pf 100 pi 220 pi 470 nl 001ml .0022 ,0047ml ,01ml .1/3SV 15/35V .22/35V .33/35V .47/35V 68/35V 1.0/35V .47 /50V 1.0/50V 3 3/50V 4.7/25V 10/25V 10/50V 22/25V 22/50V 47/25V 47/50V 10O/25V 100/50V 220/25V 220/50V 470/25V 1000/1 6V 2200/16V 50 VOIT CERAMIC DISC CAPACITORS _ iffiL .04 .03 OOVF 04 .03 0O47 M F .04 03 OI^F .04 03 022^F .04 .03 047 >l F .04 .035 ,VF 100 VOLT MYLAH FILM CAPACITORS .10 .07 ,022ml 047ml CORNER .05 .04 .035 12 .09 075 .10 .07 ■22ml ,33 2 4-20% DIPPED TANTALUMS ISOLI01 CAPACITORS -28 .23 .17 1.5/35V .30 ,2 .20 -23 .17 22/25V 31 2 28 .23 .17 3.3/25V .31 .2 .28 .23 .17 4.7/25V .32 ,21 .28 .23 .17 6B/2SV .36 .3' I5/25V .63 .51 .26 .23 .17 MINIATURE ALUMINUM ELECTROLYTIC CAPACITORS W»l Ltwl H.dl.l L»d .15 .13 .10 47/25V .15 .13 .16 .14 .11 .47/50V .16 .14 .14 .12 .09 1.0/16V .15 .13 • .15 .13 .10 1.0/25V .16 .14 -15 .13 10 1.0/5OV .16 14 16 .14 .12 4.7/16V .15 .13 .17 .15 .12 4.7/25V 15 13 .24 .20 .18 4.7/50V 16 14 .19 .17 .15 10/16V .14 12 .25 .21 ,19 10/25V 15 13 .24 .20 .18 10/SQV 16 .14 .35 .30 -28 47/50V .24 .21 .32 .28 .25 10O/16V .19 .15 .45 .41 .38 100/25V .24 .20 33 .29 27 10O/50V 35 30 .55 50 -45 220/16V ,23 .17 .70 .62 .55 470/25V .31 .28 232 BYTE September 1979 Circle 200 on inquiry card. f Transistor Checker — Completely Assembled — — Battery Operated — The ASI Transistor Checker iscap- able of checking a wide range of transistor types, either "in circuit" or out of circuit. To operate, simply plug the transistor to be checked into the front panel socket, or connect it with the alli- gator clip test leads provided. The unit safely and automatically identifies low, medium and high- power PNP and NPN transistors. Size: 35t" x 6*/4" x 2" "C" cell battery not included. Trans-Check s 19.95 ea. Custom Cables & Jumpers Part No. DB25P-4-P DB25P-4-S DB25S-4-S DJ14-1 DJ16-1 DJ24-1 DJ14-1-H DJ16-1-16 DJ24-1-24 DB 25 Series Cables Cable Length Connectors Price 4 Ft. 2-DP25P S!5.95ea. 4 Ft 1-OP25P/1-25S S16.95 ea. 4 It. 2-DP25S $17.95 ea. Dip Jumpers 1 1t i it. 1 ft. 1 it. 1 1t i n 1-14 Pin 1-16 Pin 1-24 Pin 2-14 Pin 2-16 Pin 2-24 Pin $1.59 ea 1.79 ea. 2.79 ea 2.79 ea. 3.19 ea 4.95 ea. For Cuitom Cablet ft Jumpers. 8m JAMECD 1979 Catalog lor Priclnp. CONNECTORS 25 Pin-D Subminiature DB25P las pictured) PLUG (Meets RS232) S2.95 DB25S SOCKET (Meets RS232) 13.50 DB51226-I Cable Cover lor DB25P or DB25S $1.76 PRINTED CIRCUIT EDGE-CARD ISfi Spaano-7in Double RaM-Out — Biluracieg Cooiscts — Fits 054 to 070 PC CaiOi 15/30 18/36 22/44 50/100 (.100 Spacing) 50/100 (.125 Spacing) PINS (Solder Eyelet) PINS (Solder Eyelet) PINS (Solder Eyelet) PINS (Wire Wrap) PINS (Wire Wrap) S1.9S $2.49 $2.95 $6.95 R681-1 $6.95 4-Digit Clock Kit ' Bright .357" ht. red display ' Sequential flashing colon ' 12 or 24 hour operation ' Extruded aluminum case (black) ' Pressure switches for hours, minutes & hold functions ' includes all components, case and wall transformer i Size: 3V* : IV. x 1V« JE730 $14.95 Jumbo 6-Digit Clock Kit » Four .630"ht. and two .3M"ht. common anode displays * Uses MM5314 clock chip * Switches for hours, minutes and hoi- * Hours easily viewable to 30 feet * Simulated walnut case * 115VAC operation * 12 or 24 hour operation * Includes all components, case and w * Size: 6V* x 3to x IV. JE747 $29.95 . cath- ock chip nutes JE701 • Bright .300 hi ode display • Uses MM5314 cl • Switche* lor hour and hold modes • Hrs. easily viewable to 20 ft. • Simulated walnut case • 115 VAC operation • 12 or 24 hr. operation • I net. all components, case & wall transformer • Size: < 3-1/8" IK" 6-Digit Clock Kit $19.95 REMOTE CONTROL TRANSMITTER ft RECEIVER $19.98 Digital Stopwatch Kit * Use Intersil 7205 Chip * Plated thru double-sided P.C. Board * LED display (red) * Times to 59 mln. 59.59 sec. with auto reset * Quartz crystal controlled * Three stopwatches in one: single event, split nmulatlve] 4. taylor (sequential timing) L * 5lz< s 3 pern it f: batteries 11 4.5" x 2.15" x .90" je900 $39.95 MICROPROCESSOR COMPONENTS 8212 S214 8216 8224 8228 B223 8238 8251 8253 8258 H257 8259 -BOIM/HMDA SUPPORT DEVICES- CPU 8 -Bit InpuUOutpul Priority Interrupt Control Bi-Directional Eii.-s Drrvor Clock Generator/Driver Bus Driver System Controller/Bus Driver System Controller Proj. Comm. 1/0 (USAHT) Proo Interval Timer Prorj. Periph 1/0 (PPI) Prog. DMA Control Prog. Interrupt Control 6800/6800 SUPPORT DEVICES — MPU MPU with Clock and FUm 12BXB Static Ram Penph Inter Adapt (MC6B20) Prionty Interrupt Controller 1024X8 Bit ROM (MC68A30-BI Asynchronous Comm. Adapter Synchronous Sena! Data Adapt. 0-600 bps Digital MODEM 2400 Ops Modulator -MICROPROCESSOR MANUALS- M-Z80 User Manual M-CDPtoO? User Manual M-2650 User Manual -ROM'S - 2513(2140} Character Generaior(upper case) 2513(3021) Character Generator^ lower case) 2516 Character Generator MM5230N 2048-Bit Read Only Memory SH.95 24.95 5.95 7.19 12.95 14.95 7.95 9.95 Quad3-SU1eB MICROPROCESSOR CHIPS— MISCELLANEOUS - ZB0{78DC) CPU ZB0A(780-1) CPU CDP1802 CPU 2650 MPU 6502 lil MPU w/clock, RAM. 1/0 lines PS0B5 CPU TMS9900JL 16-Bil MPU w /hardware, multiply 4 divide SHIFT REGISTERS $19.95 21.95 19.95 19.95 11.95 19.95 1995 1101 1103 2101(8101) 2102 21L02 2I11(811t) 2112 2111 2114L 2114-3 2114L-3 5101 5280/2107 74B9 74S200 93121 UPD111 (MK1027) UP0416 (MK1116) IMS4041- 45NL TMS4045 2117 256X1 1021X1 255X4 1024X1 1024X1 256X1 256X4 1024X4 1024X4 1024X4 1024X4 256X4 4096X1 16X4 256X1 256X1 4K MM500H MM503H MM504H MM506H MM510H MM5016H 2504T 2518 2522 2524 2525 2527 2528 2529 2532 2533 3341 74LS670 Dual 25 Bit Dynamic Dual 50 Bit Dynamic Dual 15 ili I Sialic Dual 100 Bit Static Dual 64 Bit Accumulator 500*512 Bit Dynamic 1024 Dynamic Hex 32 Bit Static Dual 132 Bit Static 512 Static 1024 Dynamic Dual 256 Bit Static Dual 250 Static Dual 240 Bit Susie Quad 60 Bit Slatie 1024 Static Filo - RAMS Static Dynamic Static Static Static Static Static MOS Static 450ns Sialic 450ns law power Static 300ns Static 300ns low power Static Dynamic Static Static Trisiaie Static Dynamic 16 pin Dynamic 16 pin Sialic Static Dynamic 350ns (house marked) Dynamic 14.95 14.95 1702A 2716INTEL TMS2516 <271B) TMS2532 270B 2716 T.I 82S23 B2S115 B2S123 741B6 2048 " PROMS FAMQS 16K' EPROM I6K- EPROM 'Requires single i-5V power supply 4KX8 EPROM tin EPROM 16K" EPROM 'Requires 3 voltages. 2048 ) 1024 ) 256 32XB 4096 32X8 A-Y-5-1013 30K BAUD EAM0S Tristale Bipolar Open C Bipolar Open Collector Bipolar Tristale TTL Open Collector TTL Open Collector Static 12V $5.95 59.95 49.95 89.95 10.95 29.95 9.95 3.95 2.95 CONTINENTAL SPECIALTIES Proto Board 203 *75.00 Modal Numbar PB-6 PB-100 PB-IOt LlWlH (Inchail Price 6.0 « 4.5x1.4 S1S.95 6.0x4.5x1.4 SU.95 6.0x4.5x1.4 $22,95 Proto Board 2034 9124.95 Modal LxWxH number llnclteil Pried PB-102 7.0x4.5x1.4 J251S" PD-1IB 9.0x6.0x1.4 $44.95 PB-104 9.8x8.0x1.4 S54.95 62-Key ASCII Encoder Keyboard Kit The JE610 62-Key ASCII Encoder Keyboard Kit can be interfaced into most any com- puter system. The JE610 Kit comes com- plete with an industrial grade keyboard switch assembly (62 keys), IC's, sockets, connector, electronic components and a double-sided printed wiring board. The keyboard assembly requires +5V @ 150mA and —12V @ 10mA for operation. & JE610 FEATURES: •60 Keys generate the full 128 char- acters, upper and lower case ASCII set • Fully buffered • 2 user-define keys provided for custom applications • Caps lock for upper case only alpha characters •Utilizes a 2376 (40 pin) encoder read only memory chip • Outputs directly compatible with TTL/DTL or MOS logic arrays • Easy interfacing with a 16-pin dip or 18-pin edge connector JE610 $79.95 JE200 REGULATED POWER SUPPLY $& JE20Q $14.95 5V-1 AMP POWER SUPPLY "Uses LM309K • Heat sink provided *PC Board construction • Provides a solid 1 amp @ 5 volts *Can supply up to ±5V. + 9V and +12V with JE205 Adapter *l n eludes components, hardware & instructions • Size: 3 , /5"x5"x2"H JE205 g ADAPTER BOARD -Adapts to JE200- ±5V,±9Vand±12V ■DC/DC converter w/ + 5V input •Tortodal hi-speed switching XMFR 'Short circ. protection ■PC Brd. construction ■Piggy-back to JE200 board •Size:3 1 /$"x2"x9/16"h JE205 $12.95 $10.00 Min. Order - U.S. Funds Only Spec Sheets - 254 Calif. Residents Add 6% Sales Tax 1979 Catalog Available -Send 41 i stamp Postage — Add 5% plus $1 Insurance (if desired) PHONE ORDERS WELCOME (415) 592-8097 FREE 1979A CATALOG J ameco MAIL ORDER ELECTRONICS - WORLDWIDE 1021 HOWARD AVENUE, SAN CARLOS, CA 94070 ADVERTISED PRICES GOOD THRU SEPTEMBER The Incredible "Pennywhistle 103" $139.95 Kit Only The PsnnywhliUi IDS is capable of recording data lo and from audio tape wilhoul critical speed requirements lor the recorder and il is able lo communicate directly with another modern and terminal lor telephone "hamming" and communications. In addition, it Is tree of aiiical adjust mentsand is bulit with non-precision, readily available pans. Diti Trentmlulon Method Frequency -Shift Keying, full-duplex (hall-duplei selectable). Miirmum Dili Rite 300 Baud. Dili Format Asynchronous Serial (return to mark level required between each character). Receive Channel Frequencies- . ..2025 Hi for space; 2225 Hi lor mark Trerwmlt Channel Frtquentlai ..Switch selectable Low (normal) = 1070 space, 1270 mark; High = 025 space, 2225 mark. Receive Senilthrth; --46 dam accousiically coupled. Trinim.1L.ml -15 dbm nominal. Adjustable Irom -6 dbm lo-20 dbm. Receive Frequency Tolerance ...Frequency relerence automatically adjusts lo allow lor operation between 1800 Hz and 2400 Hr. Digital Data Interlace EIA RS-232C or 20 mA current loop (receiver is opto isolated and n on -polar). Power Requirement! 120 VAC, single phase. 10 Watts. FTiyalcal All components mounl on a single 5" by 9' printed circuit board. All components included. Requires a VOM. Audio Oscillator. Frequency Counter and/or Oscilloscope to align. TRS-80 16K Conversion Kit Expand your 4K TRS-80 System to 16K. Kit comes complete with: ■ 8 each UPD416-1 (16K Dynamic Rams) 250NS * Documentation for conversion TRS-16K $75.00 COMPUTER CASSETTES .6 EACH 15 MINUTE HIGH QUALITY C-15 CASSETTES . PLASTIC CASE INCLUDED 12 CASSETTE CAPACITY . ADDITIONAL CASSETTES AVAILABLE #C-15-$2.95 sa CAS-6 $14.95 (Case and 6 Cassettes) SUP 'R' MOD II UHF Channel 33 TV Interface Unit Kit Wide Band B/W or Color System * Converts TV to Video Display for home computers, CCTV camera, Apple II, works with Cromeco Daz- zler, SOL-20, IRS-80, Challenger, etc. MOD II is prettified to Channel 33 (UHF}. * Includes coaxial cable and antenna transformer. MOD II $29.95 Kit Function Generator Kit • Provides 3 basic waveforms: sine, triangle & square wave • Frequency range Irom 1 Hz to 100K Hz • Output amplitude from 0-volts to over 6 volts (peak lo peak) • Uses a 12V supply or a ±6V split supply • Incl. chip, P.C. board, compo- nents and insl ructions. JE2206B $19.95 IDEAL FOR TRS 80 CASSETTE CONTROLLER "Plug/Jack interface to any computer system requiring remote control of cassette functions" The CC100 controls cassette motor functions, monitors tape location with its internal speaker and requires no power. Eliminates the plugging and unplugging of cables dur- ing computer loading opera- tion from cassette. #cc $29.50 Micro- Miniature Joystick • 2 each 100K pots (Linear Taper) • Printed Circuit Board Mount • Size: 1"x 1-3/16"x 1-3/16" Micro-Miniature Joystick $4.95/ Circle 201 on inquiry card. BYTE Sepeember 1979 233 Save $ on TRS-80 Products *\ TREMENDOUS > SAVINGS ON 1?r TRS-80 SYSTEMS > Complete system includes: TRS-80 Level II, w/our48KRAM, Dual MPI Disk Drives, and the APPARAT DOS+ soft- ware ($2500 value), only $2049. Line printer and desk options available. SUPERDISK TF-7D Micropolis Largest capacity mini floppy, up to 1 95 Kbytes on 77 tracks with 77TK DOS+ $699 Send for FREE Catalog A Complete Family Of Disk Drives To Choose From . . • In Stock TF-1 Pertec FD200, 5 1 A", 40 track use both sides $379 TF-3 Shugart SA400, 5 1 A", 35 tracks same as tandy $389 TF-5 MPI 5%" 40 track door lock and auto diskette $379 ejection TDH-1 Pertec Dual Head mini-floppy 35 track same $499 capacity as 2 drives All disk drive systems come complete with power supply and chassis • Two drive cable= $25 • Four drive cable= $35 PRINTERS PRINTERS PRINTERS PRINTERS LP779 Centronics 779 w/tractors LP700 Centronics 700 LP701 Centronics 701 NEC Spinwriter $1099 $1175 $1759 $2499 CENTRON LP702 Centronics 702 $1899 LP703 Centronics $2540 LP1 Centronics P1 $ 399 Centronics cables $ 39 Add-on Disk Drives DOES NOT INCLUDE POWER SUPPLY OR CHASSIS • Pertec FD200 or MPI B-52 • Shugart SA400 (unused) • Pertec Dual Head $272.00 $282.00 $399.00 NEW PRODUCTS • Small System RS232 Interface $ 49.00 • Expansion Interface w/32K $499.00 • AC Line Interference Eliminator $ 18.95 • AC Isolator (6 connectors) $ 45.95 • Telephone Interface $179.95 • Verbatum 5" soft sector Diskettes $ 3.39 IMPROVE TRS-80 PERFORMANCE WITH NEWDOS+ Over 200 modifications, corrections and enhance- ments to TRS DOS. Includes utilities. Available in two versions: 35 Track version $99 40 Track version $110 All prices cash discounted. Freight FOB/Factory Memory 16KM 16KRAM Kit Computer $74 Expansion Interface $78 «T /MCROCO/VIPUrER TECHNOLOGY INCORPORATED 2080 South Grand Ave. Santa Ana, CA 92705 (714) 979-9923 Circle 277 on inquiry card. Software • Accounts Receivable $39 • Inventory Control $39 • Job Entry/Status $75 • General Ledger $79 • Game Diskette $19 • AJA Word Processor $75 6000 E. Evans Ave., Bldg. 2 Denver, CO 80222 (303) 758-7275 p pa rat, Inc. Circle 15 on inquiry card. CaUFornia DiqiTAl Post Office Box 3097 B • Torrance, California 90503 Sankyo Magnetic Card Reader These Sankyo I/O units are capable of storing and retrieving over 400 characters of data in under two secords. The flexibility of this device lends itself t'o numerous applications. ]IAs an input reader to a computerized security system, the com- Ijputer has the ability of identifying the card holder and admitting 1 only those individuals who are authorized to enter the premises [■during specified time frames. The device is also suitable for [maintaining customer information files, or any other application where small amounts of information must be quickly entered into a data processing system. Accepts 2" by 4" HP style mag-cards. (Similar to bank cards. ) Motorized feeder pulls the magnetic card across the four channel j read/write head. NEW surplus, original cost $200. Full documentation CONNECTORS your choice f— i HOCO | DB2SP r~" ^ mile plus It hooi I ■ ' _ j DB25S female MUUUUMJL 3.95 iuuuuiu. H j ? o<- Qty. ft. male hd. 10 Hi 2.45 1.15 25 115 2.25 1.05 100 2.15 1.90 .15 WO 2.251.00 JS IK 1.07 1.37 .73 Edge Cannae tors fatal HMff .1251.250 Iks.I v/w.l2Sctattrs Altilr lold.rl. II. 140,o. specials 22/44 Klai lJ.Ht.15t" 25/50 aaMartia .150" 38/72 wldap.lt W/W.155 GOLD 100 PIN IMSAI/ALTAIR • 3.05 3/1 I 00 •4.05 3/(13.00 •5.M 3/(15.00 (1.55 3/15.00 il.09 3/(2.00 • 1.15 3/(5.00 S-100 Mother Board Quiet HEXADECIMAL KEYBOARD MaxISwitch hexadecimal kayboawds tin designed for <4 * J,4j 85 microcomputer syslema that r«qulr«4-blt output «;'i/ •■■■^T* In eUuidard hex coda. Each assembly constats of 18 hermeti- caily sua led road switches and TTL " shot" debounco circuitry. Reliable low friction acatal raaln plungers a/a cradltad (or the amooth operation and long Ufa of this premium keyboard. Rsqulraa single + 5 volt aupply. '24.88 ^s ^UNIVAC KEYBOARD Tht limoui Spoirry Univac 1710 Holianiti keyboard aiaambty 15 now i.niBbK Irom California Industrial for only $24 f!3 The iQoii compular input drrica 'or accountants and mathernilicunjj The mimetic keyi art placad On Ih* lower thiao rowi Id rttcmbl* ■ fen Hay adding mac nine This lor mil allows one handed numeric date entry. Complete with ' TEN _IPX 50 **A% Cxn^nh 9 Certified Digital 4^L SCDtCTl CASSETTES *' 3?5 ""* ND Wort drop. BIT! wTs TELETYPE MODEL 4 3 Ev.ti If w. biva t. g Ivt tk.M .way, w.t. gal.f to ship mora 43'i la 1979 than t>a anragata tf til oar compalltors. Model 43AAA «CH _JL *925. 875. TTL) 85a 825. R5-232 Interface"*." nd»7S0O ..fjpf.i ' Wt M FREE PLASTIC LIBRARY CASE with purchase of each box of .... ' itlm mInl-dlskeWei. 55 value. BOX of 10 IMOduLATOR Trio Atari R.F. Modulator allows computer data to be dla played directly upon your Istlng television system, | Thla unit converts the sig- nal Irom the Apple II and other video sources Into television frequencies. Operates Irom single 5 vol I supply. Complete ^Jit»e_^*"* ^- «H h metal case, mating VrjjV*'^^— —""^ R.F. connector and 15 feet ol coax cable. Schematics and Instructions Included. KETTES SPGCiflL APPLE (I IBK MEM OR COLOR • GRAPHICS* SOUND $1024 PLUS SH1PPIHC Mff.aui. Retail.... •1195 Diskettes | 8lnchSoft(IMH 8 inch 32 sector Mini Soft sec. Mini 10 sector Mini 16 sector hugart Associates SA800-R Floppy Disk Drive The most cost effective way to store data proc- essing information, when random recall is a prime factor. The SA800 is fully compatible with the IBM 3740 format. Write protect cir- cuitry, low maintenance & Shugart quality. >44950 KEYBOARD ASCII ENCODED KEYTRONIC ASCII & ASCII complement. ♦Ten key data pad 1 ♦ Cursor controls ♦Six user switches| * Alpha L ock *Auto repeat ♦Single 5 volt. ♦ Glass reed. NEW TRS-80$| I APPLE II 16k memory (8) 4116's • As you may be aware, publishers require advertisers to submit their ad copy 60 to 90 days prior to "press" date. That much lead time in a volatile market place, such as memory circuits, makes it extremely difficult to project future cost and availability. To obtain the best pricing on memory we have made volume commitments to our suppliers, which in turn affords us the opportunity to sell these circuits at the most competitive prices. Please contact us if you if you have a demand for volume state of the art mem- ory products. STATIC 21L02 450nS. 21L02 250nS. 2114 lKt4 450 2114 lKf.4 300 4044 4Kxl 450 4044 4Ktl 250 4045 1Kx4 450 4045 1Kc4 250 5257 low pow. 1-31 32-99 100-5C -999 1K+ 1.19 .99 .95 .90 .85 1.49 1.39 1.25 * * 5.95 5.50 5.25 4.75 4.50 8.95 8.50 8.00 * * 5.95 5.50 5.25 * * 9.95 9.50 9.00 * * 8.95 8.50 B. 00 * * 9.95 9.50 9.00 * * 5.95 5.50 5.00 4.80 4.60 SPECIAL CIRCUITS Z80A 4 MHz. 8080A CPU 8085 8086 Intel 16 bits TMS9900 16 bits 24.95 9.95 22.50 AY5-1013A UART 4.95 Floppy Disc Controllers WD 1771 single D. 39. 95 WD 1781 Double D 65. 00 WD 1791 D/D3740 * 64+ 4.00 9.00 E PROMS 1-15 16-63 1702A 2K 4.95 4.50 2708 8K 9.95 9.50 2716 5vl6K 39.95 35.00 2716 TI 24.88 20.00 2532 * * ^ !E3 PORTABLE DATA ENTRY SYSTEM These used data terminals were originally designed for chain store inventory con- trol and order entry systems. The operator enters the inventory control number, merchandise on hand and the unit price. After all pertinent data has been entered into the recorder, the main warehouse is telephoned, the handset is placed in the acoustic coupler and all the recorded information is transmitted back to the master computer. With a little Imagination and one of these portable entry systems, you should be able to exchange programs and computer information with associates across the country. Ail units were removed from service in working condition. Original cost $2,500. Each system comes complete with: •Portable Cassette Drive Unit -Five Gould "D" NiCads "DB25 Cable ■Removable Entry Keyboard ■Acoustical Coupler ..Shoulder starp with LED Display "Battery Charger "Full Documentation *-98 188 .81.73.68 | SPDT Miniature Toggles 7101 CM 0N-N0NC-0N 7107 jbt ONOFF(mnt.ON) I 7101 CK ON(momint.ON) Rocker JBT DPDT Rotary 3P-4Poi. Rotary 3P-6-Pos. Pnih B (NO.) $ 39ei. 4/S1 DIP Switch DISCOUNT HSTI1 WO UUire Wrap Center It'a not offen that California Digital ven- tures into the distribution of consumer pro- ducts, but we have reaently come accrose a product that appears so unique that we just had to add it to our product line. This is the System X-10 manufactured by the B SR turntable company. This apace age system will re- motely control any light or appliance in your home or office. Command sig- nals are transmitted from the command console over your existing wiring. From your bed or easy chair you can control up to 16 different electrical de- vices inside and outside your home. Use the System X-10 to control your stereo, television or any light fixture on the premises. The basic sampler package comes complete with command console, battery operated ultrasonic controller, one each of the appliance module, lamp mod- ule and wall switch. The basic package is priced at only $99.50 Additional modules are available for $13. 95 each. f IC SOCKETS wlr. wrap ». 25 SO low profile i«. 25 SO 17< 16 IS 37<36 35 IS 17 16 31 37 34 19 IS 17 99 93 IS 36 35 34 169 1SS 119 63 60 58 £.t KYNARwiSr .98 900 1,000 11,000 *9. SIS. (105. SS9.95 -f BW630 ' (213)679-9001 19 nil inquiry i aid COMPUCRUISE Put a computer in your car, which gives you the most effec- tive and functional cruise control ever designed, plus com- plete trip computing, fuel management sys- tems, and a remark- able accurate quartz crystal time system. So simple a child can operate, the new CompuCruise com- bines latest computer technology with state-of-the-art re- liability in a package which will not likely be available on new cars for years to come • Cruise Control 'Time, E.T., Lap Timer, Alarm • Time, Distance, Fuel to Arrival • Time, Dis- tance, Fuel to Empty • Time, Distance and Fuel on Trip • Current or Average MPG, GPH»Fuel Used, Dis- tance since Fi Hup • Current and Aver- age-Vehicle Speed • Inside, Outside or Coolant Temperature • Battery Voltage • English or Metric Display. $199.95 1 HIDSCEIU I Hi'..u'ii-:,ui L^* f* tBs^cns FLOPPY DISK STORAGE BINDER This black vinyl three-ring binder comes with ten transparent plastic sleeves which ac- commodate either twenty, five-inch or ten, eight-inch floppy disks. The' plastic sleeves may be or- dered separately and added as needed. A contents file is in- cluded with each sleeve for easy iden- tification and organiz- ing, Binder & 10 hol- ders $14.95 Part No. BBOO; Extra holders 95* each. Part No. BOD OPTO-ISOLATED PARALLEL INPUT BOARD FOR APPLE II There are 8 in- puts that can be dri- ven from TTL logic or any 5 volt source. The circuit board can be plugged into any of the 8 sockets of your Apple II. It has a 16 pin socket for standard dip ribbon cable con- nection. Board only $15.00. Part No. 120, with parts $69.95. Part Np. 120A. TIDMA • Tape Interface Direct Memory Access • Re- cord and play programs without bootstrap load- er (no prom) has FSK encoder/decoder for direct connections to low cost recorder at 1200 baud rate, and direct connections for inputs and outputs to a digital recorder at any baud rate »S-100 bus compatible • Board only $35.00 Part No. 112, with parts $110 Part No. 1 1 2A SYSTEM MONITOR 80B0, 8085, or Z-BD System monitor for use with the TIDMA board. There is no need for the front panel. Complete with documentation $12,95. 16K EPROM Uses 2708 EPROMS, memory speed selec- tion provided, ad- dressable anywhere in 65K of memory, can be shadowed in 4K in- crements. Board only $24.95 part no. 7902, with parts less EPROMs $49.95 part no. 7902A. ASCII KEYBOARD TTL & DTL compatible • Full 67 key array • Full 128 character ASCII output • Positive logic with outputs resting low • Data Strobe • Five user-definable spare keys • Standard 22 pin dual card edge connector • Requires +5VDC, 325 mA. Assembled S. Tested. Cherry Pro Part No. P70-05AB. $135.00. ASCII KEYBOARD 53 Keys popular ASR-33 format • Rugged G-10 P. C. Board • Tri-mode MOS encoding • Two-Key Rollover • MOS/DTL/TTL Compat- ible • Upper Case lockout • Data and Strobe inversion option • Three User Definable Keys • Low contact bounce • Selectable Par- ity • Custom Keycaps • George Risk Model 753. Requires +5, -12 volts. $59.95 Kit. ASCII TO CORRESPONDENCE CODE CONVERTER This bidirectional board is a direct replace- ment for the board inside the Trendata 1000 terminal. The on board connector provides RS-232 serial in and out. Sold only as an assembled and tested unit for $229.95. Part No. TA 1000C DISK JACKET™ Made from heavy duty .0095 matte plastic with reinforced grommets. The mini- diskette version holds two 5-1/4 inch disk- ettes and will fit any standard three ring binder. The pockets to the left of the disk- ette can be used for listing the contents of the disk. Please order only in multitudes of ten. $9.95/10 Pack. INTERNATIONAL MICROPROCESSOR DICTIONARY English, French, Dan- ish, German, Italian, Hungarian, Norwe- gian, Polish, Spanish, Swedish. 10 lan- guages, 28 pp. SYBEX. Ref. IMD. $4.95 VIDEO TERMINAL 16 lines, 64 columns • Upper and lower case • 5x7 dot matrix • RS-232 in -RS-232 out with TTL parallel keyboard input • On board baud rate generator 75, 110, 150, 300. 600, & 1200 jumper selecta- ble • Memory 1024 characters (7-21 L02) • Video processor chip SFF96364 by Necu- lonic • Control char- acters CCR, LF, -., *-, t, f , non destructive cursor, CS, home, CL • White characters on black background or vice-versa • With the addition of a keyboard, video monitor or TV set with TV interface (part no. 107A) and power supply this is a complete stand alone terminal 'also S-100 compatible • requires +16, S. -16 VDC at 100mA, and 8VDC at 1A. Part no. 1000A $199.95 kit. RS-232/20mA INTERFACE This board has two passive, opto-isola- ted circuits. One con- verts RS-232 to 20mA, the other con- verts 20mA to RS- 232. All connections go to a 10 pin edge connector. Requires +12 and -12 volts. Board only $9.95, part no. 7901, with parts $14.95 Part No. 7901A. COMPUCOLORII Model 3, 8K $1395. Model 4, 16K$1595. Model 5, 32K $1895. Prices include color monitor, computer, and one disk drive. mm g *— *- PET COMPUTER With 32K & monitor - $1195. Dual Disk Drive -$1195. ffccippta APPLE II PLUS 16K - $995, 32K $1059, 48K -$1123. Disk&cont $589 6502 APPLICATIONS BOOK Z80 APPLICATIONS BOOK* This book will teach you how to connect a board to the outside world and implement practical applications for the 6502, (or 280). Applications range from home con- trol (a complete alarm system, including heat sensor), to in- dustrial applications. You will learn tech- niques ranging from simulated traffic con- trol to analog-digital conversion. All exper- iments can be realized with a minimum of ex- ternal (low-cost! components. They are directly applicable to any 6502-based board such as SYM, KIM, AIM 65. This book also studies in detail input-output techniques and com- ponents, and is the I logical continuation of C202 tor C2B0). By Rodney Zaks. SYBEX. 6502: Ref. D302; Z80: Ref D380. Each $12.95 T.V. INTERFACE • Converts video, to, AM modulated RF, Channels 2 or 3. So powerful almost no tuning is required. On board regulated power supply makes this ex- tremely stable. Rated very highly in Doctor Dobbs' Journal. Recom- mended by Apple • Power required is 12 volts AC C.T., or +5 volts DC • Board only $7.60 part No. 107, with parts $1 3.50 Part No. 107A PARALLEL TRIAC OUTPUT BOARD FOR APPLE II This board has B tnacs capable of switching 110 volt 6 amp loads (660 watts per channel) or a total of 5280 watts. Board only $15.00 Part No. 210, with parts $119.95 Part No. 21 OA. TX fVfJpr • Mention part no. description, and price. In USA shipping paid by us for orders accompanied by check or money order. ' We accept C.O.D. orders in the U. S. only, or a VISA or Master Charge no., expiration date, signature, phone no., shipping charges will be added. CA residents add 6.5% for tax. Outside USA add 10% for air mail postage and han- dling. Payment must be in U. S. dollars. Dealer inquiries invited. 24 hour order line (408) 226-4064. Send for FREE Catalog ... a big self-addressed envelope with 41 'postage gets it fastest! ELECTRONIC SYSTEMS De P l - B p - ° Box 21638,SanJose, CAUSA 95151 236 BYTE September 1979 Circle 125 on inquiry card. TRS-80 ES SERIAL I/O • Can input into basic • Can use LLIST and LPRINT to output, or output continuously • RS-232 compatible • Can be used with or without the expansion bus • On board switch selectable baud rates of 110, 150,300,600, 1 900, 9400, parity or no parity odd or even, 5 to 8 data bits, and 1 or 2 stop bits. D.T.R. line • Requires +5, -12 VDC • Board only $1 9.95 Part No. 8010, with parts S59.95 Part No. 801 OA. assembled $79.95 Part No. 8010 C. No connectors pro- vided, see below. EIA/RS-232 con- nector Part No OB25PS600.«ith 9'. 8 conductor cable S1095 Part No DB25P9 nobon cable witbattached con- nectors to fit TRS- 80 end our serial board S1 9.95 Part No. 3CAB40. RS-232/ TTL INTERFACE • Converts TTL to RS- 232, and converts RS- 232 to TTL* Two sep- arate circuits • Re- quires -12 and +12 volts • All connections go to a 10 pin gold plated edge connector • Board only S4.50 Part No. 232, with parts $7.00 Part No. 232A 10 Pin edge connector $3.00 Part No. 10P MODEM • Type 1 03 • Full or half duplex • Works up to 300 baud • Origi- nate or Answer • No coils, only low cost components • TTL in- put and output-serial • Connect 8 fi speak- er and crystal mic. directly to board • Uses XR FSK demod- ulator • Requires +5 valts • Board only $7.60 Part No. 109. with parts $27.50 Part No. 109A DISKETTES Box of 10, 5" $29.95, 8" $39.95. Plastic box, holds 10 diskettes, 5" - $4.50, 8" -$6.50. RS-232/TTY INTERFACE This board has two active circuits, one converts RS-232 to 20mA, and the other converts 20mA to RS-232. Requires +12 and -12 volts. Board only $4.50 Part No. 600. with parts $7.00 Part No. 600A. S-100 BUS ACTIVE TERMINATOR Board only $14.95 Part No. 900, with parts $24.95 Part No. 900A .■: : -,V,,' !: .. APPLE IK- SERIAL I/O INTERFACE Baud rate is continuously adjustable from to 30,000 • Plugs into any peripheral connector • Low current drain. RS-232 input and output • On board switch selectable 5 to B data bits, 1 or 2 stop bits, and parity or no parity either odd or even • Jumper selectable address • SOFTWARE • Input and Output routine from monitor or BASIC to teletype or other serial printer • Program for using an Apple II for a video or an intelligent terminal. Also can output in correspondence code to interface with some selectrics. • Also watches DTR • Board only $15.00 Part No. 2, with parts $42.00 Part No. 2 A, assembled $62.00 Part No. 2C 8K EPROM piiceon Saves programs on PROM permanentlytuntil erased via UV light] up to 8K bytes. Programs may be directly run from the program saver such as fixed routines or assemblers. • S- 100 bus compatible • Room for BK bytes of EPROM non-volatile memory (2708's). • On- board PROM programming • Address relocation of each 4K of memory to any 4K boundary within 64K • Power on jump and reset jump option for "turnkey" systems and computers without a front panel • Program saver software available • Solder mask both sides • Full silkscreen for easy assembly. Program saver software in 1 2708 EPROM $25. Bare board $35 including custom coil, board with parts but no EPROMS $1 39, with 4 EPROMS $179, with 8 EPROMS $219. WAMECO PRODUCTS WITH ELECTRONIC SYSTEMS PARTS FDC-1 FLOPPY CONTROLLER BOARD will drive shugart, pertek, remex 5" SB" drives up to 8 drives, on board PROM with power boot up, will operate with CPM (not included). PCBD $42.95 FPB-1 Front Panel. (Finally) IMSAI size hex displays. Byte or instruction single step. PCBD $42.95 MEM-1A 8KxB fully buffered, S-100, uses 2102 type RAMS. PCBD $24.95, $1 68 Kit QMB-12 MOTHER BOARD, 1 3 slot, termi- nated. S-1 00 board only $34.95 $89.95 Kit CPU-1 8080A Processor board S-1 00 with 8 level vector interrupt PCBD . . $25.95 $89.95 Kit RTC-1 Realtime clock board. Two independ- ent interrupts. Software programmable. PCBD $25.95, $60.95 Kit EPM-1 1702A4K EPROM card PCBD $25.95 $49.95 with parts less EPROMS EPM-2 2708/2716 16K/32K EPROM card PCBD $24.95 $49.95 with parts less EPROMS QMB-9 MOTHER BOARD. Short Version of QMB-1 2. 9 Slots PCBD $30.95 $67.95 Kit MEM-2 16Kx8 Fully Buffered 2114 Board PCBD $25.95, $269.95 Kit T.V. TYPEWRITER • Stand alone TVT • 32 char/line, 16 lines, modifications for 64 char/line included • Parallel ASCII (TTL) input • Video output • 1 K on board memory • Output for computer controlled curser • Auto scroll • Non- destructive curser • Curser inputs: up, down, left, right, home, EOL, EDS • Scroll up, down • Requires +5 volts at 1.5 amps, and -12 volts at 30 mA • All 7400, TTL chips • Char. gen. 2513 • Upper case only • Board only $39.00 Part No. 106, with parts $145.00 Part No. 1 06A UART& BAUD RATE GENERATOR • Converts serial to parallel and parallel to serial • Low cost on board baud rate gener- ator • Baud rates: 110, 150, 300, 600, 1200, and 2400 • Low power drain +5 volts and -12 volts required • TTL com- patible • All characters contain a start bit, 5 to 8 data bits, 1 or 2 stop bits, and either odd or even parity. • All connections go to a 44 pin gold plated edge connector • Board only $12.00 Part No. 101, with parts $35.00 Part No. 101 A, 44 pin edge connector $4.00 Part No. 44P TAPE INTERFACE • Play and record Kan- sas City Standard tapes • Converts a low cost tape recorder to a digital recorder • Works up to 1200 baud* Dig- ital in and DUt are TTL- serial • Output of board connects to mic. in of recorder • Ear- phone of recorder con- nects to input on board • No coils • Requires +5 volts, low power drain • Board only $7.60 Part No. 111, with parts $27.50 Part No. 111A HEX ENCODED KEYBOARD E.S. This HEX keyboard has 1 9 keys, 1 6 encod- ed with 3 user defin- able. The encoded TTL outputs, 8-4-2-1 and STROBE are debounced and available in true and complement form. Four onboard LEDs indicate the HEX code generated for each key depression. The board requires a single +5 volt supply. Board only $15.00 Part No. HEX-3, with parts $49.95 Part No. HEX- 3A. 44 pin edge con- nector $4.00 Part No. 44P. DC POWER SUPPLY • Board supplies a regulated +5 volts at 3 amps., +1 2, -1 2, and -5 volts at 1 amp. • Power required is 8 volts AC at 3 amps., and 24 volts AC C.T. at 1.5 amps. • Board only $12.50 Part No. 6085, with parts excluding transformers $42.50 Part No. 60B5A TO Ofdfir ■ Mention P art no - description, and price. In USA shipping paid by us for orders accompanied by check or money order. 1 We accept C.O.D. orders in the U. S. only, or a VISA or Master Charge no., expiration date, signature, phone no., shipping charges will be added. CA residents add 6.5% for tax. Outside USA add 10% for air mail postage and han- dling. Payment must be in U. S. dollars. Dealer inquiries invited. 24 hour order line (408) 22B-40B4. Send for FREE Catalog ... a big self-addressed envelope with 41* postage gets it fastest! ELECTRONIC SYSTEMS De Pt- B . p - °- Box 21638,SanJose, CAUSA 95151 Circle 125 on inquiry card. BYTE September 1979 237 Circle 126 on inquiry card. The.) VTA-FRANS 1000 A completely refurbished IBM Selectric Terminal with built-in ASCII Interface. Features: $1395 300 Baud 14.9 characters per second printout Reliable heavy duty Selectric mechanism RS-232C Interface Documentation included 60 day warranty -parts and labor High quality Selectric printing Off-line use as typewriter Optional tractor feed available 15 inch carriage width HO WTO ORDER DATA-TRANS 1000 1. We accept Visa, Master Charge. Make cashiers checks or personal check payable to: DATA-TRANS 2. All orders are shipped F.O.B. San Jose, CA 3. Deliveries are immediate For orders and information DATA-TRANS 2154 0TooleSt UnitE San Jose, CA 95131 Phone: (408) 263-9246 MICRO- PROCESSORS: FROM CHIPS TO SYSTEMS This book cover all as- pects of microp- rocessors, from the basic concepts to ad- vanced interfacing techniques, in a pro- gressive presenta- tion. It is independent from any manufac- turer, and presents uniform standard principles and design techniques, including the interconnect of a standard system, as well as specific com- ponents. It intro- duces the MPU, how it works internally, the system components (ROM, RAM, UART, PIO, others), the sys- tem interconnect, applications. pro- gramming, and the problems and tech- niques of system de- velopment. By R. Zaks. SYBEX. Ref. C201.S9.95 MICRO- PROCESSOR INTERFACING TECHNIQUES Microprocessor in- terfacing is no longer an art. It is a set of techniques, and in some cases Just a set of components. This comprehensive book introduces the basic interfacing concepts and techniques, then presents in detail the implementation de- tails, from' hardware to software. It covers all the essential per- ipherals, from key- board to floppy disk, as well as the stan- dard buses (S100 to IEEE 4BB) and intro- duces the basic trou- bleshooting tech- niques. (2nd Ex- panded Edition). By Austin Lesea and R. Zaks. Ref. C207 SYBEX. $11.95 PROGRAMMING THE 6502 PROGRAMMING THEZBO PROGRAMMING THE 8080' It covers all essential aspects of program- ming, as well as the advantages and dis- advantages of the 6502 and should bring the reader to the point where he can start writing complete applications programs. For the reader who wishes more, a companion volume is available: The 6502 Applica- tions Book. By R. Zaks. 6502: Ref. C202; Z80: Ref. C280; B080: Ref. C208. SYBEX. Each $10.95 44 BUS MOTHER BOARD Has provisions for tan 44 pin (.156) connec- tors, spaced 3/4 of an inch apart. Pin 20 is connected to X, and 22 is connected to Z for power and ground. All the other pins are connected in parallel. This board also has provisions for bypass capacitors. Board cost $15.00 Part No. 102. Connectors $3.00 each Part No. 44WP. AN INTRODUCTION TO PERSONAL AND BUSINESS COMPUTING No computer back- ground is required. The book is designed to educate the reader in all the aspects of a system, from the se- lection of the mic- rocomputer to the required peripherals. By Rodnay Zaks. Ref. C200, SYBEX $6.95 TVT COOKBOOK Bk 1064 — by Don Lancaster. Describes the use of a standard television receiver as a microprocessor CRT terminal: Ex- plains and describes character genera- tion, cursor control and interface infor- mation in typical, easy -to- understand Lan- cascaster style $9.95 COMPUTER PROGRAMMING HANDBOOK A complete guide to computer programm- ing & data process- ing. Includes many worked-out examples. By Peter Staak, TAB $9.95 DIGITAL CASSETTE 5 min. each side. Box of 10 $9.95. Part No. C-5. Tq QrHgf ■ Mention part no. description, and price. In USA shipping paid by us for orders accompanied by check or money order. 1 V\fe accept COD. orders in the U. S. only, or a VISA or Master Charge no., expiration date, signature, phone no., shipping charges will be added. CA residents add 6.5% for tax. Outside USA add 10% for air mail postage and han- dling. Payment must be in U. S. dollars. Dealer inquiries invited. 24 hour order line (408) 226-4064. Send for FREE Catalog ... a big self-addressed envelope with 41 e postage gets it fastest! ELECTRONIC SYSTEMS °* b. P. 0. Box 21638, San Jose, CA USA 95151 238 BYTE September 1979 Circle 125 on inquiry card. PERQOM SAMPLER a r tMf 0ti 300 ' j»[F30M <^l For your CIS-30+ SS-50 bus computer — the • Interface to data terminal and hvo cas- sette recorders with a unit only 1/10 the size of SWTP's AC-30. • Select 30, 60, or 120 bytes per second cassette interfacing, 300, 600 or 1200 baud data terminal interfacing. • Optional mod kits make CIS-30+ work with any microcomputer. (For MITS 680b, ask for Tech Memo TM-CIS- 30+— 09.) • KC-Standard/Bi-Phase-M (double fre- quency) cassette data encoding. De- pendable self-clocking operation. • Ordinary functions may be accom- plished with 6800 Mikbug™ monitor. • Prices: Kit, $79.95; Assembled, $99.95. Prices include a comprehensive instruction manual. Also available: Test Cassette, Re- mote Control Kit (for program control of recorders), IC Socket Kit, MITS 680b mod documentation, Universal Adaptor Kit (converts CIS-30+ tor use with any com- puter). MIKBUG®Motorola, Inc. In the Product Development Queue . . . Coming PDQ. Watch lor announce- ments. 6809 Processor Card — With this SS-50 bus PC board, you'll be able to upgrade with the microprocessor that Motorola designers describe as the "best 8-bit machine so far made by humans." The Electric Crayon™ — This color graphics system includes its own /nP and interfaces to virtually any microcomputer with a parallel I/O port. Printer Interface — For your TRS-80™. Interface any serial RS232 printer to your TRS-80™ with this system. '"ELECTRIC WINDOW. ELECTRIC CRAYON. Pilon- 30 and Pilon-10 are trademarks of Percom Data Company, Inc. TRS-80 is a trademark of Tandy Corporation and Radio Shack which has no relationship to Percom Data Company. Orders may be paid by check or money order, or charged to Visa or Master Charge credit account. Texas residents must add 5% sales tai. For your data storage — Pllon-30™ and Pilon-10™ data cassettes • Orders-of-magnitude improvement in data integrity over ordinary audio cas- settes. • Pilon-coated pressure pad eliminates lint-producing felt pad of standard audio cassettes. • Smooth pilon coating minimizes erra- tic tape motion. • Foam pad spring is energy absorbing. Superior to leaf spring mounted pad which tends to oscillate and cause flut- ter. • Five-screw case design virtually pre- cludes deformation during assembly. • Price: $2.49. For your S-100 computer— the CI-812 • Both cassette and data terminal inter- facing on one S-100 bus PC board. • Interfaces two recorders. Record and playback circuits are independent. • Select 30, 60, 120, or 240 bytes per second cassette interfacing, 110 to 9600 baud data terminal interfacing. • KC-Standard/Bi-Phase-M (double fre- quency) encoded cassette data. De- pendable self-clocking operation. • Optional firmware (2708 EPROM) Operating System available. • Prices: kit, $99.95; assembled, $129.95. Prices include a comprehensive instruction manual. In addition to the EPROM Operating System, a Test Cassette, Remote Control Kit (for program control of recorders), and an IC Socket Kit are also available. CASSETTE SOFTWARE For 8080/Z-80 ju.C« .. . . BASIC ETC — Developed by the co- authors of the original Tiny BASIC, BASIC ETC is easy to use yet includes com- mands and functions required for power- ful business and scientific programs as well as for hobby applications. 9.5K bytes of RAM. 1200-baud cassette and 42-page user's manual $35.00 Cassette Operating System — EPROM (2708) COS for the Percom CI-812 dual peripheral interfacing PC card . . $39.95 If you're programming on a 6800 fiC, you'll want these development and de- bugging programs written by Ed Smith of the Software Works: Disassembler/Source Generator — Dis- assembles SWTP Resident Assembler, TSC Mnemonic Assembler/Text Editor or Smoke Signal Mnemonic Assembler/Text Editor and produces compacted source code suitable for re-editing. Prints or dis- plays full assembly-type output listing. 4K bytes of RAM. (Order M68SG) $25.00 Disassembler/Trace — Use to examine (or examine and execute) any area of RAM or ROM. "Software-single-step" through any program, change the con- tents of CPU or memory location at any time, trace subroutines to any depth. 2.3K bytes of RAM. (Order M68DT) $20.00 EPROM Support/Relocator Program — This program relocates a program in any contiguous area of RAM or ROM to any- where in RAM. Use to assemble and test programs in RAM, adjust programs for EPROM operating addresses and then block move to your EPROM burner ad- dress. 952 bytes of RAM. Loads at hex 1000. (Order M68EP) $20.00 Relocating Assembler & Linking Loader (M68AS) $50.00 Relocating Disassembler & Segmented Source Teit Generator (M68RS) $35.00 Americana Plus — 1 4 tunes for the New- tech Model 68 Music Board in machine language ready to load and run. Cassette compatible with Percom CIS-30+ and SWTP AC-30. Order MC-1SW . . $15.95 HARDWARE Newtech Model 68 Music Board — Pro- duces melodies, rhythms, sound effects, morse code, etc. from your programs. Includes manual with BASIC for writing music scores and assembly language routine to play them. Installs in SWTP I/O slot. Assembled & tested $59.95 The Percom ELECTRIC WINDOW™ — Memory-resident and programmable, this video display character generator board for your SS-50 bus displays up to 24 80-character lines. Features dual character generators, dual-intensity high-lighting. One programmable regis- ter controls scrolling. Compatible with standard video monitors $249.95 SS-50 Prototype Cards: Large card (up to 70 40-pin ICs) $24.95 I/O size card $14.95 PERCOM™ 'peripherals for personal computing' PERCOM DATA COMPANY, INC. DEPT. B 211N.KIRBY* GARLAND, TX. 75042 To order products or request additional lit- erature, call Percom's toll-free number: 1-800-527-1592. For detail technical In- formation call (214) 272-3421. Circle 306 on inquiry card. BYTE September 1979 239 P.O. Box 4430X Santa Clara, CA 95054 ATTENTION ELF OWNERS ANNOUNCING QUEST SUPER BASIC At last a Full Size Basic for 1802 systems. A complete function Basic Including two dimen- sional arrays, string variables, floating point, arithmetic and 32 bit signed integer arithmetic (10 digit accuracy) with I/O routines. Easily adap- table on most 1802 systems. Requires 12K RAM minimum for Basic and user programs. Cassette version in stock now for Immediate delivery. ROM versions coming soon with exchange privilege allowing credit for cassette version. Super Basic on Cassette $40.00 Tiny Basic Source now available $19.00 S-100 Slot Expansion. Add 3 more S-100 slots to your Super Expansion Board or use as a 4 slot S-100 Mother Board. Board without connectors $9.95. Coming Soon: High resolution alpha/numerics with color graphics expandable up to 256 x 192 resolution for less than $100. Economical ver- sions for other popular 1802 systems also. 16K Dynamic RAM board expandable to 32K for less than $150. RCA Cosmac Super Elf Computer $106.95 Compare features before you decide to buy any other computer. There is no other computer on the market today that has all the desirable bene- fits of the Super Elf for so little money. The Super Elf is a small single board computer that does many big things. It Is an excellent computer for training and for learning programming with its machine language and yet it is easily expanded with additional memory, Full Basic, ASCII Keyboards, video character generation, etc. Before you buy another small computer, see if it includes the following features: ROM monitor: State and Mode displays; Single step: Optional address displays: Power Supply; Audio Amplifier and Speaker; Fully socketed for all IC's; Real cost of in warranty repairs; Full documentation. The Super Elf includes a ROM monitor for pro- gram loading, editing and execution with SINGLE STEP for program debugging which is not In- cluded in others at the same price. With SINGLE STEP you can see the microprocessor chip opera- ting with the unique Quest address and data bus displays belore, during and after executing in- structions. Also, CPU mode and instruction cycle are decoded and displayed on 8 LED indicators. An RCA 1861 video graphics chip allows you to connect to your own TV with an Inexpensive video modulator to do graphics and games. There Is a speaker system included for writing your own music or using many music programs already written. The speaker amplifier may also be used to drive relays for control purposes. A 24 key HEX keyboard Includes 16 HEX keys plus load, mat, run, wait, Input, memory pro- tact, monitor select and single step. Large, on board displays provide output and optional high and low address. There is a 44 pin standard connector slot for PC cards and a 50 pin connec- tor slot for the Quest Super Expansion Board. Power supply and sockets for all IC's are in- cluded in the price plus a detailed 127 pg. instruc- tion manual which now includes over 40 pgs. of software info. Including a series of lessons to help get you started and a music program and graphics target game. Many schools and universities are using the Super Elf as a course of study. OEM's use It for training and research and development. Remember, other computers only offer Super Elf features at additional cost or not at all. Compare belore you buy. Super Elf Kit $105.95, High address option $8.95, Low address option $9.95. Custom Cabinet with drilled and labelled plexiglass front panel $24.95. Expansion Cabinet with room for 4 S-100 boards $41.00. NICed Battery Memory Saver Kit $5.95. All kits and options also come completely assembled and tested. Questdata, a 12 page monthly software publica- tion for 1802 computer users Is available by sub- scription for $12.00 per year. Tiny Basic Cassette $10.00, on ROM $38.00, original Elf kit board $14.95. Super Expansion Board with Cassette Interface $89.95 This is truly an astounding valuel This board has been designed to allow you to decide how you want it optioned. The Super Expansion Board comes with 4K of low power RAM fully address- able anywhere In 64K with built-in memory pro- tect and a cassette Interlace. Provisions have been made for all other options on the same board and it fits neatly into the hardwood cabinet alongside the Super Ell. The board includes slots for up to 6K of EPROM (2708, 2758, 2716 or Tl 2716) and is fully socketed. EPROM can be used tor the monitor and Tiny Basic or other purposes. A K Super ROM Monitor $19.95 is available as an on board option in 2708 EPROM which has been preprogrammed with a program loader/ editor and error checking multi file cassette read/write software, (relocatible cassette file) another exclusive from Quest. It Includes register save and readout, block move capability and video graphics driver with blinking cursor. Break points can be used with the register save feature to isolate program bugs quickly, then follow with single step. The Super Monitor is written with subroutines allowing users to take advantage of monitor functions simply by calling them up. Improvements and revisions are easily done with the monitor. If you have the Super Expansion Board and Super Monitor the monitor is up and running at the push of a button. Other on board options Include Parallel Input and Output Ports with lull handshake. They allow easy connection of an ASCII keyboard to the input port. RS 232 and 20 ma Current Loop for teletype or other device are on board and if you need more memory there are two S-100 slots for static RAM or video boards. A Godbout 8K RAM board is available for $135.00. Also a 1K Super Monitor version 2 with video driver for full capa- bility display with Tiny Basic and a video Interface board. Parallel I/O Ports $9.85, RS 232 $4.50, TTY 20 ma l/F $1.95, S-100 $4.50. A 50 pin connector sat with ribbon cable Is available at $12.50 for easy connection between the Super Ell and the Super Expansion Board. The Power Supply Kit for the Super Expansion Board is a 5 amp supply with multiple positive and negative voltages $29.95. Add $4.00 for shipping. Prepunched frame $7. 50. Case $10.00. Add $1.50 for shipping. Multi-volt Computer Power Supply 8v 5 amp, ±18v .5 amp, 5v 1.5 amp, -5v .5 amp, 12v .5 amp, -12 option. ±5v, ±12v are regulated. Kit $29.95. Kit with punched frame $37.45. Woodgrain case $10.00. 60 Hz Crystal Time Base Kit $4.40 Converts digital clocks from AC line frequency to crystal time base. Outstanding accuracy. Kit includes: PC board, IC, crystal, resistors, ca- pacitors and trimmer. TERMS: SD. 00 mm. order U.S. Funds. Calif residents add 6% tax. BankAmencard and Master Charge accepted. Shipping charges will be added on charge cards. Same day shipmont. First line parts only. Factory tested. Guaranteed money back. Quality IC's and other components at fac- tory prices. INTEGRATED CIRCUITS 7IWTTI 740QN 740IN 7«4N 7409M 7410N 7414N 74ZON 7422N 7430N 7442N 7445N 7447M 744BN 7450N 7474N 7475N 7485N 7489N 7490N 7492N 7493N 7495N 741 DON 74107N 74121N 741 23N 741 2 SN 74 MSN 74150H 74I51N 74154N 741 57N 74161N 7416ZN 74163N 74174N 741 75N 74I90N 74192H 74193N 74221 N 7429BN 74365N 743GSN 74367N .86 74LSWTTL 74LS00N .25 74LS02H .25 74LS04K .25 74LS05H .25 74LS06N 25 74LS10N .25 74LSI3N 40 74LS14N 90 74LS20N .25 74L522N .25 7JI.S2BM .41 74LS30N .25 74LS33N .39 741S3BN .30 74LS74N .70 74LS75N .47 74L59QN .51 74LSS3N 51 74LS95N 1 69 74LS107N 35 74LS112N .35 74LS113N .35 74LS13ZN .72 74LS136N .35 74LS151N .67 74LSI55N .67 74LS157N .67 74LS162N Jt 74LS163N .91 74LS174H .95 74LS190N 1.06 74LS221N 1.95 74LS25BN -87 MLS367N 1,35 UttEAR CA3045 .90 CA3046 67 CA3061 1.80 CA3082 1 90 CA30BB 2.95 LM301 AN/AK .35 LM305H .87 LM307N .35 LM308N B9 LM309H 115 LM309K 1-50 LM311H/N 90 LM317T/K ?m LM31B 1M LM320K-5 1?n a,m LM320K-12 w\ LM320K-15 1.15 LM320T-S 1 (Ml LM320TB i n LH320T-12 IM LM320T-1S i no LM324N 1,15 LM339H 1,55 LM340K-5 1.35 LM340K-B 1 35 CM340K-12 138 LM340K-15 135 LM340K-24 1.35 LM340T-5 1,W LM340T-B 1 ?ft LM340T-12 175 LM340T-15 175 LM340T-1£ i n LM340T-2J 125 LM343H 450 LM350 750 LM370 1.15 LM377 :iiio LM379 100 LM3S0N 1.00 IM3SI i m LM382 t no LM703H 40 LM709H 78 LM723H/N SO LM733N 87 LM741CM Vt LM741N 75 LM747H/N .87 LM746N .35 LM1303N .82 LM1304 1,10 LM1305 17/ LM1307 ■I (ill L.M1310 7 7fi LM145B 47 LM1800 1 75 LM1S12 750 LM1889 3 00 LM2111 1.75 LM29C2 150 LM39O0N Ml 1 75 LM3909N 81 MC1458V 50 NES40L ?m NE5SON .65 NE555V 4.1 NE556A .79 NE5GSA 1.00 NE5B6V inn NE567V 1,70 NE570B 5 00 HE571B soo 7BL05 (Ml 7BL08 80 78M05 85 75108 175 7549 1CN SO 55 7549 4CN .89 Ala U CONVERTER 803BB 4fi0 B700CJ 13 95 8701 CN V mi 875QCJ L013Q 'I'lS 8400CJV/I 7 40 ICL7103 g u ICL7107 14.25 F*K. CD4O00 CD4O01 C04002 CD 4006 CD40Q7 CO 4001) CD4O09 CD4O10 CD4011 C040I7 CD4013 CD4014 CD4015 CD401E CD4017 CD401B CD40I9 CO4020 C04021 CD4022 CD4DZ3 CD4074 CO4025 CD4026 CD4027 C0402B CD40Z9 C04030 CO 4035 C04040 CD4042 C04043 CD4044 CD4046 CD4049 C040S0 CD4D51 CD40S0 CO 4056 CD406B C04069 C04070 CO4071 CO4072 CO 4073 C04075 CD4076 CD4076 CD4081 CD4082 CD4116 CD4490 CO 4507 C0450B CD4510 CD4511 C04515 CD4516 C04518 C04520 CD4527 CD4528 CD4S53 CD4566 CD4583 CD45B5 CD40192 74C00 74C04 74C10 74C14 74C2Q 74C30 74C48 74C74 74C76 74C90 74C93 74C154 74C160 740175 74C192 74C221 74C905 74C90G 74C914 74C922 74C923 74C925 74C926 74C927 8T20 5T23 8T24 BT25 8T26 8T28 BT97 BT9B RAM 2101-1 2102-1 2102AL-4 21L02-1 21F02 2104A-4 2107B-4 2111-1 2112-2 2114L-3 inns 2513B R30 MM5262 40 MM52BO 300 MM5320 9 05 MM5330 SM PD411D-3 400 PD411D-4 5 00 P5101L 1395 4200A 9 95 82S25 2.00 91L02A 1.50 HD0165-5 695 MM57100 4R0 G 1 AY 38500- n»(> MCM657IA 9 95 936B 3.50 NB2SI36 8.75 NB2S137 B75 270B 10.50 DM8577 2.90 8223 2.90 2716T1 29.50 271B Intel 48.00 CONNECTORS 44 pin edge 2.75 100 pin edge 4.50 100 pin edge. WW 5.25 IC SOCKETS Bolder Tin Low Profile PIN 1UP PIN 1UP 18 77 36 .58 RESISTORS V. wot 5\ 10 per type 03 1000 per rype 01: 25 per type 025 350 piece peck 100 per type .015 5 per type 6.7! KEYBOARDS 56 key ASCII keyboard *til 167.50 Fully assembled 77.50 53 key ASCII keyboard kR 60 00 Fully assembled 70.00 Enclosure 14 95 uos Red T018 .15 Green. Yellow T016 .20 Jumbo Red 20 Gieen. Orange. Yellow Jumt» 25 Cllplfle LED Mounting Clips 87*175 (specify red. amber, green, yellow, deai) CONTINENTAL SPECIALTIES In Hock Complete line ol breadboard lesi equip 20 79 40 .57 MAM DO 8 dlgH Frtq. Or. 1445 CLOCKS MU5314 MM5315 MM5369 MM5B41 MM5885 CnOOl 5.80 CT7010 8.95 CT7015 7.25 HW5375AA/N 3.90 MM5375AG/N 4.90 7205 16.50 7207 720B 7209 4.» OS0026CN 3 75 050056CN 3.75 MH53104 250 MICnOFKOCESSOR 68O0 1750 6802 18.75 15.95 B0B5 ZBOA 8212 8214 8218 B224 8228 8251 B253 B255 8257 ptae. 13.91 tB02DP plis. 17.95 1B61P 11.50 COP1802CD 19.95 COP1602D 25" CDP1861 6820 6850 6507 6504 6522 UART.'FIFO AY5-1013 AY5-1014 3341 PflOM 1702A N82S23 NS2S123 N82S126 N82S129 N82S131 12.9S 9.95 12.95 12.50 16 50 13.60 WIRE WRAP LEVEL 3 16 .33 28 100 18 57 40 1 23 5MHi 10 MM.' 18 MHz 20MH1 32 MM 32768 MHi 1 B432MH2 3.5795 MHz 2.01DOMH1 2 097152 MHi 2.4576 Mm 3.276B MHi 5.0688 MKi 5 165 MHz 5.7143 MHz 6.5536 MHi 14.31818 MHi 18.432 MHz 22.11B4MHi KEYBOARD ENCODERS AY57376 $12.50 AY5-3600 17.95 74C922 5.50 74C923 5 50 HD0165-5 6.95 D Connecton RS232 D325P 2.95 DB25S 3.95 Cover 1.50 RS232 Complete Set 6.50 DE9S 1.95 0A15P 2.10 DA15S 3 10 TRANSISTORS 2H1893 40 2N2222A IB 2N2369 30 2N2904A 70 2N2907A .25 2N3053 .40 2H363B 25 2N3643 75 2N3904 .IS 2N3906 IS 2N3055 69 2N4400 75 2N4401 .75 2N4402 .20 TIP31 TIP33A SPECIAL PRODUCTS MM586S Stopwatch Timer 9 00 PC board 7 50 Swttchel Mom Pushbutton 27 3 pos lade .25 Encoder HDQ165S 6.95 3 Dlitl Univ. nil Counter Board Kit Operates 5-1B Voll DC lo 5 MHi typ- 125' LED display 10.80 Pintronlti 1D0A Logic Antlyiar Kit 1224.00 Model 10 Triggei if KB 1229.00 Model 150 Bus Grabber KK $369.00 Sinciilr Jli Olgri MiKJmeler III 15 Clort Calendar Ktl 123. K 2.5 MHz FreqoencT Countir Kll 137.50 30 MHr Friquency Countet Kll (47.76 TRANSFORMERS 6V 300 ma 3.25 12 Volt 300 m* IranilOf m« 175 12 6VCT600m» 3.75 12V 250 ma wan plug 2.95 12V CT 250 ma wan plug 3.50 24V CT 400 ma 3 95 10V 17 amp will plug 4 65 12V 6 amp 12 95 DISPLAY L£DS MAN1 CA 270 2 MANS CC 125 MAN72/74 CA/CA 300 1 OL704 CC 300 1 0L7D7(TJL707R CA 300 1 0L727/728 CA/CC .500 1 CA7CC 600 1 CC BOO 1 CC 357 cacA 500 1 CC/CA 500 CC/CA BOO 2 DL747/750 DL750 FND359 FNO50O/5O7 FND503/510 FNO8O0/8O7 3 ciiji: BuDOle 4 digit Bubble 0G8 Fluorescent DG10 Fluorescent 5 digit 14 pin display NSN69 9 digit display 7520 Claires photocells TIL311 Hex MA1001A 8.95 MA1012A 8.98 102P3 Iranerormer 27S Additional Drive Krt iy Din Kll S665 00 Rockwell AIM 65 Computer 6502 based single board with full ASCII keyboard and 20 column thermal printer. 20 char, al- phanumeric display, ROM monitor, fully expand- able. $375.00. 4K version $450.00. 4K Assem- bler $85.00, 8K Basic Interpreter $100.00. Power supply assy, in case $60.00. AIM 65 in thin briefcase with power supply $485.00. Not a Cheap Clock Kit $14.95 Includes everything except case. 2- PC boards. 6-.50" LED Displays. 5314 clock chip, trans- former, all components and full Instructions. Orange displays also avail. Same kit w/.80" displays. Red only. $21.95 Case $11.75 Video Modular Kit $8.95 Convert your TV set into a high quality monitor without affecting normal usage. Complete kit with full instructions. S-100 Computer Boards 8K Static RAM Kit Godbout $135.00 16K Static RAM Kit 265.00 24K Static RAM Kit 423.00 32K Dynamic RAM Kit 310.00 64K Dynamic RAM Kit 470.00 8K/16K Eprom Kit (less PROMS) $89.00 Video Interface Kit $139.00 Motherboard $39. Extender Board $8.99 79 IC Update Master Manual $35.00 Complete IC data selector, 2500 pg. master refer- ence guide. Over 50,000 cross references. Free update service through 1979. Domestic postage $3.50. 1978 IC Master closeout $1 9.50. No foreign orders. Auto Clock Kit $17.95 DC clock with 4-.50" displays. Uses National MA-1012 module with alarm option. Includes light dimmer, crystal timebase PC boards. Fully regulated, comp. instructs. Add $3.95 for beau- tiful dark gray case. Best value anywhere. Stopwatch Kit $26.95 Full six digit battery operated. 2-5 volts. 3.2768 MHz crystal accuracy. Times to 59 min. , 59 sec. , 99 1/100 sec. Times std. , split and Taylor. 7205 chip, all components minus case. Full Instructions. NiCad Battery Fixer/Charger Kit Opens shorted cells that won't hold a charge and then charges them up, all in one kit w/full parts and instructions. $7.25 PROM Eraser Will erase 25 PROMs in 15 minutes. Ultra- violet, assembled $34.50 Hickok 3Vz Digit LCD Multimeter Batt/AC oper. 0.1mv-1000v. 5 ranges. 0.5% accur. Resistance 6 low power ranges 0.1 ohm-20M ohm. DC curr. .01 to 100ma. Hand held, W LCD displays, auto zero, polarity, over- range. $69.95. Digital Temp. Meter Kit $39.95 Indoor and outdoor. Switches back and forth. Beautiful. 50" LED readouts. Nothing like it available, Needs no additional parts for com- plete, full operation. Will measure -100° to + 200°F, tenths of a degree, air or liquid. Beautiful woodgrain case w/bezel $11.75 FREE: Send lor your copy ol our NEW 1979 QUEST CATALOG. Include 28c stamp. 240 BYTE September 1979 Circle 311 on inquiry card. The EXPANDORAM is available in versions from 16K up to 64K, so for a minimum investment you can have a memory system that will grow with your needs. This is a dynamic memory with the in- visable on-board refresh, and IT WORKS! • Interfaces with Altair, IMSAI, SOL-8, Cromenco, SBC-100, and others. • Bank Selectable • Phantom • Power 8VDC, ± 16VDC, 5 Watts • Lowest Cost Per Bit • Uses Popular 4116 RAMS • PC Board is doubled solder masked and has silk-screen parts layout. our new retail loca SD EXPANDORAM 1U ttiUmatt, S-fOO THentMy Circle 312 or Extensive documentation clear- ly written Complete Kit includes all Sockets for 64K Memory access time: 375ns, Cycle time: 500ns. No wait states required. 16K boundries and Protection via Dip Switches Designed to work with Z-80, 8080, 8085 CPU's. )ISC DRIVES EXPAND0 64KIT(4116) 16K $249 32K $324 48K $399 64K $474 SHUGART SA 400 5'/." 110 KB. 35 tracks, SHUGART SA 400 $295.00 SHUGART SA 400 Willi attractive metal case with cutouts lor Data Cable switch. luse and power cord LOBO SA400-C $325.00 SHUGART SA400 with Cabinet and Power Supply. Assembled, tested & guaranteed LOBO SA400-PSC $395.00 SHUGART 801R 8" 6 4 megabits, single or double density, hard Or soft sector, writB protect, and more SHUGART 801R $449.00 Siemens FDD 200-3 8" double-sided double density $650.00 DISC CONTROLLER SD "VERSAFLOPPY" Kit The Versatile Floppy Disk Hnlu '1 <^Q Controller Y'"* ' OT FEATURES: IBM 3740 Soft Sectored Compati- ble. S-100 BUS Compatible for Z-80 or 8080. Con- trols up to 4 Drives {single or double sided). Directly controls the following drives: 1. Shugart SA400/450 Mini Floppy 2. Shugart SA800/850 Standard Floppy. 3. PERSCI 70 and 277. 4. MFE 700/750. 5. CDC 9404/9406. 6. GSI/Siemans FDD120-8. 34 Pin Connector for Mini Floppy. 50 Pin Con nector tor Standard Floppy. Operates with modified CP/M operating system and C-Basic Compiler. The new "Versafloppy" from S.D. Computer Products provides complete control for many of the available Floppy Disk Drives. Both Mini and Full Size. FD1771B-1 Single Den- sity Controller Chip. Listings for Control Soft- ware are Included In price. „ . /«/*nn L CPM for SD Versafloppy & 1 00 lr DUAL SHUGAR DISC DRIVES with"DOWf New from Lobo Drives, a dual Cabinet complete with"power supply; and Shugart 801 R disc drives. • Cabinet accepts 2 801 R drives mounted side by side horizontally. • Power Supply for 2 drives • Ad-on drives available • Assembled, tested and guaranteed by Lobo Drives. • Single or double density • Hard or soft sector • Write Protect • Capacity: Unformatted single density 3.2 megabits double density 6.4 i BM format, 2 megabits 500 KBS transfer, 77 tracks. • Shugart 800 Series Compatible LOBO 801R-1 Pes. Dual Cabinet with 1 drive ....J. $599.00 LOBO 801 R-2 Pes. Dual Cabinet with 2 drives $1025.00 SHUGART 801R Ad-on disc drive $449.00 • bing k»Cap on rV500 ector • Write Proti megabits i megabits,^^L .Z\f. $59! r CQNriNfNTAL SPECIALTIES CORPORATION LOGIC PROBES Logic Probes and Digital Pulsers *«* "^ ^ CSC logic probes are (he ultimate tool for breadboard design and testing. These hand held units provide an Instant overview of circuit conditions. Simple lo use; just clip power leads to circuit's power supply, set logic family switch lo TTUDTL or CMOS/HTL. Touch probB to test node. Trace logic levels and pulses through digital circuits. Even stretch and latch for easy pulse detection. Instanl recognition of high, low or Invalid levels, open circuits and nodes. Simple, dual-level detector LEDs tell It quickly, correct- ly. HI (Logic "1"): LO (Logic "0"). Also Incorporates blinking pulse detector, e.g.. HI and LO LED3 blink on or off. tracking "1" or "0" states at square wave Irequencles up to 1.5 MHz. Pulse LED blinks on for V, second during pulse transition. Choice of three models to meet individual requirements; budget, project and speed ol logic circuits. MODEL LP-1 Hand-held logic probe provides instant reading of logic levels for TTL, DTL. HTL or CMOS. Input Impadanca: 100,000 ohms. Minimum Detectable Pulie: 50 ns. Maximum Input Signal (Frequency): 10 MHz Pulaa Detector (LED): High speed train or single event. Pulse Memory: Pulse or level transition detected and stored. -^ — kCSC Modal LP-1 Logic Probe-Net Each -M*9$ $42.70 MODEL LP-2 Economy version of Model LP-1. Safer than a vollmeter. More accurate lhan a scope. Input Impedance: 300,000 ohms. Minimum Detectable Pulee: 300 ns. Maximum Input Signal (Frequency): 1.5 MHz. Pulee Detector (LED): High speed train or single event. Pulaa Memory: None. _^ - CSC Model LP-2 Logic Probe— Nel Each 04rf3f $23.70 MODEL LP-3 High speed logic probe. Captures pulses as short as 10 tw> Input Im- pedance: 500,000 ohms. Minimum Detectable Pulee: 10 ns. Maximum Input Signal (Frequency): 50 MHz. Pulaa Detector (LED): High speed train or single event. Pulae Memory: Pulse or level transition detected and stored. CSC Model LP-3 Logic Probe-Net Each 3fotfc$5 $66.45 DIGITAL PULSER The ultimate In speed and ease of operation. Simply connect clip leads to .Itlve and negative power, then touch OP-1's probe to a circuit node; automatic polarity sensor detects circuit's high or low condition, Depress the pushbutton and trigger an opposite polarity pulse into the circuit. Fast troubleshooting includes injecting signals at key points in TTL, DTL, CMOS or other popular circuits. Test with single pulse or 100 pulses per second via built-in dual control push-button; button selects single shol or con- tinuous modes. LED indicator monitors operating modes by flashing once for single pulse or continuously tor a pulse train. Completely automatic, pencil-size lab/field pulse generator for any family of digital circuits. Out- put: Tri-state. Polarity: Pulse-sensing auto-polarity. Sync and Source: 100 mA. Pulae Train; 100 pps. LED Indicator: Flashes for single pulse; stays lit for pulse train. CSC Model DPI Digital Pulaer-Nel Each £743$5 $71 .20 SD COMPUTER BOARDS $319 KIT* VDB-8024 Video Display Board With On-Board Z80 Microprocessor • ['nil HIM 'hnmelcr* by U4 llnodlsjiluy • Ctarectcre dttplnycd by Iflflfi Revolu- tion 7x10 Matrix » Kcyhiiurd Timer iuut Interface • ComptaHtc Video Output • Separate TTL Level SpM*ronb»Uon urn! Vldin ( hsipulf. • 2K BytCH Independent (hi Board Memory • Ow-DoanJZttOMlcropnwcwtof • ClU'lii-WDlHoluY • 'M I 'jijiL-r tun) Lower CaacCharactcru • lYl Special ChanictcrSci • \SH Additional »*er Programmable Chafactcm • Full Cursor Control • Forward und Reverse Scrolling Capability • OjierutcsuHun Independent Term Inn! • Vurlnble Speed Display Rale • Blinking, Underlining, Field Reverse. Field I'niieci mid (lomtiinuUiinM $239 KIT' — -n-w SBC-100 Single Board Computer with Onboard RAM, PROM, CTC • Four Channel (.ountcr.'Tlnier (ZaO-CTC) • Software Prof) rain in utile Hand Generator • S-IOO Bus Compatible ■ No From Panel Required (or Ope ■ OpUnnid Vectored Iniemipt* • ZSOCcntnd ProccAaWg t'nit • lM • Serial Input/Outum fun « $249 Z80 Starter Kit A Complete Microcomputer on a Board I Synchro Oiieruilori • I'iimiMi'I I ■ . | .. . Asv.H PRIORITY ONE ELECTRONICS 16723B Roscoe Blvd. Sepulvedo, CA 91343 Terms: Visa, MC, BAC, Check, Money Order, C.O.D. U.S. Funds Only. CA residents add 6% sales lax. Minimum order $10.00, Prepaid U.S. orders less lhan $75.00 include 5% shipping and handling, minimum $2.50. Excess refunded. Just in case . . . please include your phone no. Prices subject to change without notice. We will do our best to maintain prices thru Sept. 1979. OEM and Institutional Dhone orders welcome (213) 894-8171. (800) 423-5633 inquiries invited. '/.HO ('crural Processing I ■ III Kith IBB • Twolli.dlreeUi.nulH-lili IfUltatHt? Instruction* WO) < )n Ikitinl Keyboard uml Display • SwiicliSelcciulilel'kDMiirM Kuiisns Cliv Stundurd Cum write Kesian Interlace • ^K line KIH'ti Minilitir In RUM I'ROM I'ni^runinierlliilll ni-hnurd .Meinunli.MimlnctiiKlCllanKe lixpuiisiiin provtslatl lor 01 iS-HX) ■ fttrtu^iitneonilCliunge C otoieetors • ZHdCI'lRcKlt.terl'.-mniiiicmi.lCliiu Wire \Vru|i nreu liircnstini el mil in, • I piitnEViigrmiiMiuliH-Hrcukpiitiiih SliiHlcfiV.ilil>iH.niitiniwl en mil • Klngte'Siep Ihniugh RAM m PROM programming • Andiiit UHHCtle Ijiudiind lhiui|i IK Bytes nf RAM (lwqnu dabte ti «K • Vectored Imemipi* imwtdetl hv 1 Ivies) ZHO-CTfuiidZHtM'H) IK Itoes ui RAM (lycpu ilatile u UK • Itlcull'iirl^K-rluicntuliiiluiKl Bytes) KvtUuaUngibeXB(l<*11' ■iOiuimel llunlwurcCni U-rrTlmi r i/jvu-W) ORDER TOLL FREE 1-800-423-5633 ORDER TOLL FREE 1-800-423-5633 Visit our new retai TRS-80 DISC DRIVE $ 395 V Shugart SA400, housed in an attractive metal case, complete with power supply and termination net- work. All you need to do is connect the drives to your expansion interface. 1410 $835°° * Separate integral 12-Key Numeric Pad itiw www . All 128 ASCII Codes • 64 Oisplayable Characters • 24x80 Screen Configuration ^^^"^ TC^T * H '9 n Resolution using a 5x7 Dot Matrix ■»— ™" mSm • TTY-Style Keyboard Layout • Cursor Addressing and Sensing • EIA Interlace • Eight Selectable Transmission Rates up to 9600 Baud Microprocessor Based • Remote Commands • Attractive Styling for Contemporary En- vironments Hazeltlne 1400 same as 1410 less numeric pad '735 1 " 1 HaKftnetttt 1500 Reg. $=r*25 s 1098 00 -ah i28Asoii codes • 94 Displayable Characters Including Lower Case • 24x80 Screen Configuration • High-Resolution Characters Using a 7x10 Dot Matrix 1 ANSI Standard Keyboard Layout in- cluding Numeric Pad 1 Cursor Addressing and Sensing 1 Dual Intensity ► EIA and 20MA Interface i • Nine Selectable Transmission Rates Up to 19.2 KB • Auxiliary EIA Output • Remote Editing Commands • Standard or Reverse Video !*• Microprocessor Based HazettW 600 ALL THE FEATURES OF THE "1500" PLUS . . . • Cursor Control Keys • Protected/Unprotected Data > Transmit Page, Line or Batches of Infor- mation ■ Function Keys— up to 127 » Tab/Back Tab/Auto Tab • Format Mode with Insert and Delete Line Keys > 31 Remote Commands including "Ter- minal Status" J 510 Reg.j5J8t£ s 1175 ALL THE FEATURES OF THE "1510" PLUS... Separate Microprocessor-Controlled Printer In- terface which allows: • Interfacing of both serial and parallel printers • Printer speed Independent of communications baud rate • Printer control codes to be sent by the CPU and received by the printer without restriction or alteration of the terminal (especially useful for wide carriage applications) ' Information to be transmitted directly to either the printer or the terminal, or to both • Operating Modes/Remote Commands; Remote/Local Print; Printer On-Llne ^with/without Display; Printer Off-Une 1520 Reg. $t660T s 1495 00 PRICE DOES NOT INCLUDE SHIPPING • Use with TRS-80 • Parallel interface • Continuous variable printing density 80-132 characters per line • 5x7 dot matrix • Prints on plain paper, sheets, rolls, fan fold • Form thickness control • Horizontal and vertical form positioning .-"' CENTRONICS 779 PRINTERS Portable Miniscopes fori Electronic Professionals on the Go!!! The Standout Oscilloscope development of the I decade!!! Now -30MHz, dual trace] model. Compare the performance, then compare the price. 1-inrettGiKMKiiniO0UMJctl|2 rwrllD" l?SunHrnnlh !M(W»»Cing VBCIOi iu't numur Mll'2. « rnounli IGrit IKIcipiulinK ID' tiH"sion • rnciij-jss richf rj c*Cu>U »"0 inuiuci-oni lo> ooi.on ol Mini* tHi« us. or "ailing l*rm.njtiont > LfgtDuMl *SVmoGMDl104MPS) *u !".■:■ Cuntrt.»r.noijit[>«MiL i'H.'i.iMM 1*1 SAl HOsa m<:«orisuir « tiurot' ourO 1„ Price: $29.50 RS232 & "D" TYPE CONNECTORS P = Plug Male S = Socket-Female C = Cover-Hood PART NO. DE-9P DE8S DE-9C DA15P DA15S DA1SC 08 25P OB-25S DB51212-1 DESCRIPTION 9 Pm Mate 9 Pin Female 9 Pin Cover 15 Pin Male 15 Pin Female 15 Pin Cover 25 Pin Male 25 Pin F»mnle 1 pc. Grey Hood DB1 226-1 A 2 pc Black Hood D8110963-3 2 pc. Gray Hood PRICE ■4 S-9 HICKOK LX303 $74.95 3 LEVEL GOLD WIRE WRAP SOCKETS Sockets purchased In multiples of 50 per type may be combined lor best price. 11 'n muMfrU i M'inr J T\ 15 =i 1 2.2 50 130 1.15 DC37P DC37S DC37C DDSOP DO50S ODSOC 02041 8S 37 Pin Mai 37 Pin Female 37 Pm Cover 50 Pin Male 50 Pm Female 50 Pin Cover Hardware Set (2 pa 2.20 2.00 3.20 3.00 1.80 1.45 2.M 2.50 3.75 3.85 1.85 1.40 1.90 1.80 1.80 1.55 3.95 3 SO 575 5.50 2.20 1.95 4.95 47S 7.50 7.20 2.50 2.20 1.00 .80 Connector lor CENTRONICS 700 SERIES: Amphenol 57-30360 lor back of Centronics 700 Series printers 1.4-S900 5.UP-S7 50 S10O-WWO 50/100 Conl. .125 ctrs 3 LEVEL WIRE WRAP 025" sq. posts on 250 spaced rows GOLD PLATED 1-4 5-0 10-34 1400 13 75 13.50 DIP S100ALT 501100 Conl 125 ctrs SOLDER TAIL on .140 spaced rows ALTAIR motherboards GOLD Dialed 14 5.0 10-24 14.50 S4.25 14.00 DIP S100STO 501100 Cont. . 50LDER TAIL on 250 spaced rows loi VECTOR. IMSAI. CROMENCO mother boards GOLD plated. 1-4 50 10-24 S3.50 13.25 13.00 S10OSE 501100 Com 125 ctrs PIERCED SOLDER EYELET tails GOLD 1-4 5-6- 10-24 55.00 54.50 54.00 Other Popular Edge Connoctors 156 ctrs PIERCED i. GOLD plated 10-24 52.20 53.55 53.70 IMSAI Slyle Card Guides 5/51 00 See our July Ad for many other connectors. 25-99 100-249 250999 Spin 14 pin 16 pin 18 pin 20 pin 22 pin 24 pin 28 pin 40 pin .39 .50 .70 .90 .95 .95 1.25 .36 .38 .42 .60 .85 1.15 .34 .36 .40 .55 .75 .80 .80 1.00 .31 .32 .36 .50 .65 .70 .70 .95 All sockets are GOLD 3 level closed entry. 2 level Tail, Low Profile, Tin Sockets and Dip Plugs available. CALL FOR QUOTATION APPLE PLUGBOARD Vector 4609 Peripheral Interface Plugboard (or construction of custom circuits. Plug compatible with Apple II. Commodore PET and Super Kim microcomputers. Three connectors, in addition to the standard 25/50 system bus. are available for input/oulput. A 20/40-contact card-edge connector, fabricated on the rear of the board, mates with a 3-M type ribbon connector. Alternatively, a right-angle solder-tail header may be positioned in this same location. The Model 4609 also accomodates the miniature SIP-type connectors which may be placed on the periphery or in mid-board. 1-4 5-9 10-24 $19.95 $17.96 $15.96 Plugboards 8800V Universal Miciocompuler/ofocessor plugboard, use will) S-100 bus Com- plete with heal sink & hardware 5.3" it 10' x 1/16 1-4 5-9 10-21 S19.95 S17.95 S15.96 8601-1 Same as 8800V except plain less power Ouses & Heal sink 1-4 5-9 10-24 $15.22 $13.79 $12.18 3682 9.6"x4.5" S10.97 3682-2 6.5" X 4.5" 19.81 Hi-Density Dual-ln-Line Plugboard lor Wire Wrap wilh Power & Grd. Bus Epoxy Glass 1/16" 44 pin con. spaced .156 Phenolic PART NO. 64P44XXXP 169P44XXXP 1M6 tfxfflt BOARD .042 dia holes on 0.1 spacing for IC's PRICE SIZE 1-9 10-19 4.5x6.5" $1.56 $1.40 4.5x17" $3.69 $3.32 TRS-80/APPLE MEMORY EXPANSION KITS 4116's RAMS from Leading Manutactumrs <16Kx1 200ns) 8 lor $75.00 3677 9 6"x4.5" $10.90 3677-2 6.5" X 4.5" $9.74 Gen. Purpose D.I. P. Boards wilh Bus Patlern lor Solder or Wire Wrap. Epoxy Glass 1/16" 44 pin ct n. s paced .156 r r l 3662 6.5' r X 4.5' m $7.65 3662-2 9.6" x 4.5" $11.45 P pattern plugboards for IC's Epoxy Glass 1/16" 44 pin con. spaced .156 Add $3.00 for programming Jumpers for TRS-80 Keyboard IC SOCKET SALE 14 pin Low Profile 10/&2.10 100/$1*».00 16 pin Low Profile 10/$2.20 100/S16.00 24 pin Low Profile 3/$1.00 40/S10.00 40 pin Solder Tail 3/$ 1.00 40/S10.00 24 pin Dip Plug with cover 3/$1.004Q/$10.00 3690-12 CARD EXTENDER Card Extender has 100 con- tacts 50 per side on .125 centers-Attached connec- tor-is compatible with S-100 Bus Systems. $25.83 3690 6.5" 22/44 pin .156 ctrs. Exten ders $13 .17^ 3 14 & 16 PIN GOLD 3 LEVEL WIRE WRAP SOCKES 14 - G3 100 for $33.00 16 - G3 100 for $33.00 50 of each for $35.00 J MEMORY MEMORY 2102LIPC Low Power 450ns in lots of 25 $1.10 2102AL-2 Low Power 250ns in lots of 25 $1.25 21 14-3LlKx4 300 ns Low Power 8/S50.00 5257-3L 4Kx1 300ns Low Power 8/550.00 2708 8K 450ns EPROM $9.00 2716 16K 5 Volt Only EPROM $45.00 Tg&& PANAVISE TILTS. TURNS, AND , ROTATES TO ANY POSITION. IT HOLDS YOUR WORK . EXACTLY WHERE YOU WANT IT. WRAP. POST for .042 dia. holes | {all boards on this page) IT44/C pkg. 100 . . S 2.34 IT44/M pkg. 1000 $14.35 I A-13 hand installing toot $ 2.94 IM-10A List $89.00 SPECIAL 556.95 with tube Perfectly balanced fluoroacont lighting with precision magnifier lens. Tough thermoplastic shade. Easy lens re- moval. New wire clip design permits easy Installation and removal of fluorescent tube. Comes with plastic shield to protect tube from soiling and damage. Colors: Gray, Black, and Chocolate Brawn. Comas with on* 22 watt T-S Circlln* fiuorea cam tub^3dloptar janjL ^ I ELECTRONICS * ORDER TOLL FREE 1 80042356; except CA., AK., Hi., Call (213) 894-8171 16723B Roscoe Blvd. Sepulveda CA 91343 Terms: Visa, MC, BAC. Check, Money Order, CO.D. U.S. Funds Only. CA residents add 6% sales tax Minimum order $10.00. Prepaid U.S. orders less than $75.00 include 5% shipping and handling minimum $2.50. Excess refunded. Just in case . . . please include your phone no. Prices subject to change without notice. We will do our best to maintain prices thru Sept. 1979. OEM and Institutional hone orders welcome (213) 894-8171, (800) 423-5633 inquiries invited. TEST EQUIPMENT CALL FOB SPECIAL PRICES ORDER TOLL FREE 1-800-423-5633 ORDER TOLL FREE 1-800-423-5633 Venus 2001 Video Board Assembled & Tested $259.95 •Complete Unit with 4K Memory and Video Driver on Eprom assembled and tested $339.95 kit 199 95 OPTIONAL: • Sockets $10.00 • 2K Memory $30.00 • 4K Memory $60.00 • Video Driver Eprom $20.00 • S-100 plug-in • Parallel keyboard port On board 4K Screen Memory (Optional). On board Eprom (Optional) for Video Driver or Text Editor Software. Up and down scrolling through video memory Reverse Video, Blinking Characters. Display : 128 ASC1 1 Characters 64 X 32 or 32 X 16 Screen format (Jumper Selectable). 7 by 11 Dot Matrix Characters. American or European TV Compatible (CRT Controls Programable) Dealer Inquiries Invited 32-K Static RAM $499. • S-100 Plug-In • Kit includes P.C. board, all parts and assembly manual • Uses 21 14L, 450 nS. I.C. sockets -$20.00 P.C. BOARD BY S-100 CO. 16-K Static RAM 249- • S-100 Plug-In Kit includes P.C. board, all parts and assembly manual. Uses2114L450 nS. Sockets -$10.00 Add $40.00 for 300 nS (4MHz) RAMS P.C. BOARD BY WAMECO z-80 cpu $125. • S-100 Plug-In Kit includes P.C. boards, all parts and assembly manual. FEATURES: 2MHz operation • S-100 plug-in Power-on jump • On board provision for 2708 (optional at $12.95). P.C. BOARD BY ITHACA AUDIO ASCII Keyboard Kit $ 79.95 Assembled and Tested $95.95 • Single +5V Supply • Full ASCII Set (Upper and Lower Case) • Parallel Output • Positive and Negetave Strobe • 2 Key Rollover • 3 User Definable Keys • P.C. Board Size: 17-3/16" X 5" • Control Characters Molded on Key Caps • Optional Provision For Serial Output OPTIONAL: Metal Enclosure $27.50 • Edge Con. $2.00 • Sockets $4.00 • Upper Case Lock Switch $2.50 • Shift Register (For Serial Output) $2.00 Dealer Inquiries Invited Apple II I/O Board Kit Plugs into Slot of Mother Board • 1 8 Bit Parallel Output Port (Expands to 3 Ports) • 1 Input Port • 15mA Output Current Sink or Source • Can be used for peripheral equipment such as printers, floppy discs, cassettes, paper tapes, etc. • 1 free software listing for SWTP PR40 or IBM selectric. PRICE: 1 Input and 1 Output Port $49.00 1 Input and 3 Output Ports $64.00 Dealer Inquiries Invited new ! A DREAM COME TRUE lntroducing:30 MHZ DUAL TRACE PORTABLE SCOPE «„_ for an % CCC amazing \_r\JiJt • Dual trace 2-channel; separate, chopped or alternate modes. • 30 megahertz bandwidth. • External and internal trigger. • Time base - 0.05 .Microseconds to 0.2 SEC/div 21 settings • Battery or line operation. • Line synchronization mode. • Power consumption less than 50W. • Vertical gain - 0.1 to 50 volts/div- 12 settings. • Size: 2.9" H 6.4" W 8.5" D. • Weighs only 3.5 lbs. with batteries. • Complete with input cable and rechargeable batteries and charger unit. OPTIONAL: Leather case $45.00 • 10:1 probe $27.00 (2 for $49.00) ■■ MS -21 5 15 mhz Dual Trace Portable Scope $ 399. MS-1515 mhz Single Trace Scope $ 299. MODEL MS 230 SHIPPING $3.50 / California residents add 6% sales tax ELECTRONICS WAREHOUSE Inc 15820 Hawthorne Boulevard Lawndale, CA 90260 (213) 370-5551 Circle 130 on inquiry card. Circle 1 on inquiry card. FRFFI UPT0S170 IN ' *■*■*■■ MERCHANDISE WITH THE PURCHASE OF ONE OF THE FOLLOWING PET-CBM ITEMS!! ASK ABOUT EDUCATIONAL DISCOUNTS ON PET $119.00 $ 2.25 $ 1.60 IEEE - RS232 Printer Adaptor for PET BETSI PET to S-100 Interface & Motherboard PET Connectors- Parallel or IEEE - Cassette Port Personal Information Management System- Add $3 for PET program cassette Protect-A-Pet dust cover MICROCHESS for PET (Peter Jennings) PET 4 Voice Music Board (MTUK-1002-2) Music Software (K-1002-3C) for PET CmC Word Processor program for PET Bridge Challenger program for PET Adventure 1 for 24K PET Tunnel Vision/Kat & Mouse-maze Graphics Utility Package for PET Stimulating Simulations-Book & PET tape Kite Fight - 2 player action game Write for PET Software List Auto-Repeat Hardware for PET Word Processor for PET — Machine Language version. Auto scroll, insert, delete, form letter append, etc. 8K Version $ 24.00 16K or 32K with disk $ 95.00 * Amount of Free Merchandise with Purchase of PET-CBM Item. PET SPECIALS ust FREE* PET 16N 16K full size graphics keyboard $ 995 $130 PET 16B 16K full size business keyboard $ 995 $130 PET 32N 32K full size graphics keyboard $1295 $170 PET 32B 32K full size business keyboard $1295 $170 PET 16S 16K small keyboard, integral cassette $ 995 $130 PET32S 32K small keyboard, integral cassette $1295 $170 PET 8K 8K small keyboard, integral cassette $ 795 $100 PET 2040 Dual Disk Drive - 343,000 bytes $1295 $170 PET 2040A Single Disk Drive - 171,000 bytes $ 895 $115 PET 2022 Traclor Feed Printer $ 995 $130 PET 2023 Pressure Feed Printer $ 849 $110 PET C2N External Cassette Deck $ 95 $ 12 $ 79.50 WRITE FOR 6502 AND S-100 PRODUCT LIST KIM-1 $159 (Add $30lor Power Supply)SYM-1 BAS-1 Microsoft ROM Basic for SYM Memory Plus SEA-16 New 16K Static RAM Seawell Motherboard-4K RAM space KTM-2 Synertek Keyboard and Video Interface with Graphics Capability RAM 16 4MHz 16K Static S-100 2114 L 450ns 4K Static RAM 2716 EPROM (5 Volt) 6550 RAM (for PET 8K) 6502 Microprocessor Chip 6522 VIA 6520 PIA $222 $ 85 $199 $325 $ 99 1.90 $ 9.50 $ 17.90 $ 49.00 $ 19.00 $ 25.00 $ 13.50 $ 7.95 $ 7.95 $ 13.50 $ 13.50 $ 7.95 $ 24.50 ' FREE! UP TO $170 IN MERCHANDISE BOOKS Programming the 6502 (Zaks) 6502 Applications Book (Zaks) 6500 Programming Manual (MOS) Programming a Microcomputer:6502 Basic for Home Computers $290 $270 $6.95 $ 45 $13.90 $ 9.95 $9.75 $10.50 $ 9.90 $11.90 $ 6.50 $ 8.90 $ 5.90 3M "Scotch" 8" disks 10/$3I 3M "Scotch" 5" diskettes SALE 10/J35 Verbatim 5" diskettes TO/527 (Write for quantity prices) Minimum Order $10.00 A B Computers Cassettes (all tapes guaranteed) Premium quality, high output lownoise in 5 screw housing with labels: C-10 10/5.95 50/25.00 100/48.00 C-30 10/7.00 50/30.00 100/57.00 115-A E. Stump Road Montgomery ville, PA 18936 (215)699-8386 WAMECO THE COMPLETE PC BOARD HOUSE EVERYTHING FOR THE S-100 BUSS * FPB-1 FRONT PANEL BOARD * EPM-2 16K or 32K BYTE EPROM Hex Displays, IMSAI Replaceable $54.95 2708 or 2176 interchangeable $30.00 * FDC-1 FLOPPY DISC CONTROLLER BOARD * QMB-9 9 SLOT MOTHER BOARD Controls up to 8 Discs $45.00 Terminated $35.00 *MEM-1A 8K BYTE 2102 RAM Board ....$31.95 *QMB-12 12 SLOT MOTHER BOARD *MEM-2 16K BYTE 2114 RAM Board ....$31.95 Terminated $40.00 *CPU-1 8080A CPU Board * RTC REALTIME CLOCK With Vector Interrupt $31.95 Programmable Interrupts ., $27.95 *EPM-1 4K BYTE 1702A EPROM $29.95 FUTURE PRODUCTS: 80 CHARACTER VIDEO BOARD, IO BOARD WITH CASSETTE INTERFACE. DEALER INQUIRIES INVITED, UNIVERSITY DISCOUNTS AVAILABLE AT YOUR LOCAL DEALER W7J7C iflC. WAMECO INC. 111 GLENN WAY #8, BELMONT, CA 94002 (415)592-6141 Circle 387 on inquiry card. BYTE September 1979 245 Circle 384 on inquiry card. 10%OFF 20 OFF YOUR OWN TRS-80 SYSTEM AT TREMENDOUS SAVINGS Centronics 730 Same as Line Printer II Special 1st 25 units sold OTRS-80 Complete System DISK DRIVES NOW IN STOCK/ Includes: CPU/ Keyboard, Power Supply, Video Monitor, Cassette Recorder, Manual, and Game Cassette. ©Line Printer ©Mini Disk System OC-10 Cassettes ©Verbatim Diskettes i REG. PRICE OUR PRICE $ 696.00 $ 557.10 ITEM TRS-80 Complete System Level II • 4K RAM TRS-80 Complete System Level II 16 K RAM $988.00 $764.10 Expansion Interface $ 299.00 $ 269.10 Pertec FD200 Mini Disk Drive $ 495.00 $ 385.00 Centronics 779 Printer $1599.00 $1175.00 Centronics 101 Printer $1595.00 $1400 00 Anadex DP-8000 Printer $1295.00 $995 00 Centronics P1 Printer $ 534.00 $ 445.00 TrendatalOOO $1495.00 $1295.00 Memory KM16K) $ 199.00 $ 96.00 ■FREE INSTALLATION Verbatim Diskettes ea. $ 595 3 $ 17.89 10 $ 59.00 Maxell Diskettes ea. $ 10.00 3 $ 30.00 10 $ 100.00 C-10 Cassettes 5 $ 4.95 25 $ 24.75 12 S 29.95 fanfold. C-30 Cassettes Paper (9V;' x 11 3500 sheets) Model Level II— 4K Level II— 16K Expansion Interlace 4.95 12.00 37 00 7.50 21 00 60.00 450 18.75 23 95 $ 35.00 $ 29.95 List Price Our Price $698.00 $628.20 $988.00 $889.20 $299.00 $269.10 $ 850 Reg. $ 895 Anadex 9500 Similar to Line Printer III $1,295 Reg. $1,999 * All printers include cables There are new developments every day — write or call lor the latest information. Outlet Hours: Mon.-Fri.; 9 am.- Sat. 12— 5 pm. -7 pm. 777 Henderson Boulevard N-6 Folcroft Industrial Park Folcroft PA 19032 (215) 461-5300 m TOLL FREE 1-(800) 345-8102 'Orders only! FOREIGN and DOMESTIC DISTRIBUTORSHIPS AVAILABLE niiiitiiiiiiniiimimininiif BUILD YOUR OWN LOW COST MICRO-COMPUTER POWER SUPPLIES FOR S-100 BUS, FLOPPY DISCS, ETC. POWER TRANSFORMERS (with mounting brackets) ITEM NO. USED IN KIT NO. PRI. WINDING TAPS SECONDARY WINDING OUTPUTS 2x8 Vac 2x14 Vac 2x24 Vac SIZE Wx D x H UNIT PRICE T1 T 2 T 3 T 4 0V, 110V, 120V 0V, 110V, 120V 0V, 110V, 120V 0V, 110V, 120V 2x9A 2X12.5A 2x9A 2x4.5A 2x2.5A 2X3.5A 2x2.5A 2x2.5A 2x4.5A 3%"x3 5 /a"x3ya" 3%"x4%"x3 1 /8" 3%"x4Wx3 1 /b" 3%"x3%"x3V8" 19.95 25.95 27.95 19.95 POWER SUPPLY KITS (open frame with base plate, 3 hrs. assy, time) ITEM USED FOR @+8Vdc @-8Vdc @+16Vdc @-16Vdc @+28Vdc SIZEWxDxH UNIT PRICE KIT 1 18 CARDS SOURCE 18A KIT 2 SYSTEM SOURCE 25A KIT 3 DISC SYSTEM 18A KIT 4 DISC SOURCE 8A 1A 1A 2.5A 3A 2A 2.5A 3A 2A 4A 8A 12"x6"x4%" 12"x6"x4%" 14"x6"x4%" 10"x6"x4%" 46.95 54.95 62.95 44.95 EACH KIT INCLUDES: TRANSFORMER, CAPACITORS, RESIS., BRIDGE RECTIFIERS, FUSE & HOLDER, TERMINAL BLOCK, BASE PLATE, MOUNTING PARTS AND INSTRUCTIONS. REGULATED POWER SUPPLY "R2" assy. & tested, open frame, size: 9" x 5" (D) x 5" (H) $69.95 SPECS: +5V +1%, @ 5A, +24V, +1%, @ 5A. OVERCURRENT PROTECTION AND +5% ADJ. FOR BOTH VOLTAGES. REMARK: IDEAL FOR ROCKWELL AIM-65 MICROCOMPUTER. ALSO -5V, @ 1A OPTIONAL, $5.00 ADDITIONAL. - SHIPPING FOR EACH TRANSFORMER: $4.75. FOR EACH POWER SUPPLY: $5.00 IN CALIF. $7.00 IN OTHER STATES. CALIF. RESIDENTS ADD 6% SALES TAX. OEM WELCOME. MAIL ORDER: P.O. BOX 4296 TORRANCE, CA 90510 SUNNY INTERNATIONAL (TRANSFORMERS MANUFACTURER) Telephone: (213) 633-8327 STORE: 7245 E. ALONDRA BLVD. PARAMOUNT, CA 90723 STORE HOURS: 9 AM-6 PM 246 BYTE September 1979 Circle 354 on inquiry card. ••• ••• ••• ••• ••• •••• :•.... ••••• ••••• ••••■ §•••• §•••• ••••• ••••• !•••• >•••■ • •••• • •••• • •••• • ••■< • ••■< «... • ••.. • •••• • ••••■ • •••• #••••< • •••• • ••••' • ••••< • • •••• • ••••• • •••< •••• {•••• • •••• #•■•■ • •••• • ••• • •••• • •«•• • •••• §••••< • *•• • •••• • •*.. 16K EPROM CARD-S 100 BUSS OUR BEST SELLING KIT! USES 2708s! Thousands of personal and business systems around the world use this board with complete satisfaction. Puts 1 6K of software on line at ALL TIMES! Kit features a top quality soldermasked and silk-screened PC board and first run parts and sockets. All parts (except 2708's) are included. Any number of EPROM locations may be disabled to avoid any memory conflicts. Fully buffered and has WAIT STATE capabilities. OUR 450NS 2708'S ARE $8.95 EA. WITH PURCHASE OF KIT ASSEMBLED AND FULLY TESTED ADD $25 8K LOW POWER RAM KIT-S 100 BUSS 250 NS SALE! 'ADD $5 FOR 250NS! $129 KIT (450 NS RAMS!) Thousands of computer systems rely on this rugged, work horse, RAM board. Designed for error-free, NO HASSLE, systems use. KIT FEATURES: 1 Doubled sided PC Board with solder mask and silk screen layout. Gold plated contact fingers. 2. All sockets included. 3. Fully buffered on all address and data lines. 4. Phantom is jumper selectable to pin 67. 5. FOUR 7805 regulators are provided v on card. Blank PC Board w/Documentation $29.95 Low Profile Socket Set. ..13.50 Support ICs (TTL & Regulators) $9.75 Bypass CAP'S (Disc & Tantalums) $4.50 ASSEMBLED AND FULLY BURNED IN ADD $30 , 16K STATIC RAM KIT-S 100 BUSS \r $ 279 KIT PRICE CUT! FULLY STATIC, AT DYNAMIC PRICES .11 I I I I 1 I I I I I I I I I I 1....... ..■.■■!■■ VJUkk WHY THE 2114 RAM CHIP? We (eel Ihe2114willbethenexi industry standard RAM chip (like the 2102 was} This means price. availability, and quality will all be good! Next, the 2114 is FULLY STATIC We feel this is the ONLY way to go on the S-100 Buss' We've all heard the HORROR siones about some Dynamic Ram Boards having trouble with DMA and FLOPPY DISC DRIVES Who needs these kinds ot problems 7 And finally, even among other 4K Static RAM's the 21 14 stands out r Not all 4K static Rams are created equal! Some of the other 4K's have clocked chip enable lines and various timing windows fuil m critical as Dynamic RAM's Some of our competitor's 16K boards use these "tricky" devices But not us! The 21 14 is the ONLY logical choice for a irouble-tree. straightforward design. KIT FEATURES: 1. Addressable as four separate 4K Blocks. 2. ON BOARD BANK SELECT circuitry. (Cromemco Standard!) Allows up to 512K on line! 3. Uses 21 14 (450NS) 4K Static Rams A ON BOARD SELECTABLE WAIT STATES 5 Double sided PC Board, with solder mask and silk screened layout. Gold plated contact fingers 6. All address and data lines fully buffered 7. Kit includes ALL parts and sockets. 8. PHANTOM is jumpered to PIN 67 9. LOW POWER under 2 amps TYPICAL from the ■*6 Volt Buss. 10. Blank PC Board can be populated as any multiple of 4K. BLANK PC BOARD W/DATA— $33 LOW PROFILE SOCKET SET-$12 ASSEMBLED & TESTED-ADD $30 SUPPORT ICS & CAPS-$19.9S 2114 RAM'S-8 FOR $69.95 J 16K STATIC RAM SS-50 BUSS s 295 KIT FULLY STATIC AT DYNAMIC PRICES KIT FEATURES: FOR SWTPC 6800 BUSS! ASSEMBLED AND TESTED - $30 1. Addressable on 16K Boundaries 2. Uses 2114 Static Ram 3. Runs at Full Speed 4. Double sided PC Board. Solder mask and silk screened layout. Gold fingers. 5. All Parts and Sockets included 6. Low Power: Under 2 Amps Typical BLANK PC BOARD— S33 COMPLETE SOCKET SET— S12 SUPPORT ICS AND CAPS-S19.95 NEW! G.I. COMPUTER SOUND CHIP AY3-8910. As featured in July. 1979 BYTE! A fantastically powerful Sound & Music Generator. Perfect for use with any 8 Bit Microprocessor. Contains: 3 Tone Channel, Noise Generator, 3 Channels of Amplitude Control, 16 Bit Envelope Period Control, 2-8 Bit Parallel I/O. 3 D to A Converters, plus much more! All in one 40 Pin DIP. Super easy to interface to the S-100 or other busses. SPECIAL OFFER: $14.95 each Add $3 for 64 page Data Manual. Initial slock very limited FIRST COME FIRST = EFIVED' Z-80 PROGRAMMING MANUAL By MOSTEK, or ZILOG. The most detailed explanation ever on the working of the Z-80 CPU CHIPS. At least one full page on each of the 158 Z-80 instructions. A MUST reference manual for any user of the Z-80. 300 pages. Just off the press. $12.95 PROC. TECH. QUITS THE MICROPROCESSOR BUSINESS! FACTORY CLOSE OUT - SPECIAL PURCHASE! #16KRA 16K S-100 Dynamic Ram Board - $149. 95 ORIGINALLY PRICED AT $429 each! We purchased the remaining inventory of PT's popular 16K Ram Board when they recently closed their plant. Don't miss the boat! These are brand new, fully tested, ASSEMBLED and ready to go. All are sold with our standard 90 day limited warranty!! 72 Page Full Manual, Included Free! NOT ASSOCIATED WITH DIGITAL RESEARCH OF CALIFORNIA. THE SUPPLIERS OF CPM SOFTWARE. Erf Digital Research: Computers ••;::: a •••••A P.O. Box 401565 GARLAND, TEXAS 75040 • (214) 271-2461 TERMS: Add soc postafic w pny hulanri' Oidetsiinilpi NnCOH Wo arropt Visn MastcrCh.iitiP and Anioi.cn Res add 5", Tax Fntpipn ni dpi r (oxcrpt Canada add ^O" Rack Guarantor 1 on alt Moms :if. add 75C handling i Expross raid? Tpx P&H SWPnvMowv ;>:. ••••• >*••• ■•••• ••••• ••••• ••••• ••»•• ••••• ••••• ••••• ••••• ••••• ••••• ••••• ••••• ••••• ••••• ■•••• ••••• ■•••• ••••• •••••• ••••• ■••••• ••••• •••••• <•«••• ■••••• ■■•••• ■••••• •••••• ■••••• •••••• '••••• ■••••• •••••• ■■•••• -••••$ •••••• •••#•• ■••••• — ••• ■••••• •••••• -•••• •••••• -••••§ ■••••• ■••••• •••••• •••••§ •••••# ■••••• ■••••• •••••• ■••••• ■••••• — ••• •••••• •••••• •••••§ •••••• ••»••• •••••• •••••• •••••• • •••••§ •••••§ •••••• •••••• ■••••• •••••# •••••• ■••••• •••••• ■••••• •••••• ■••••• •••••• •••••• ■••••• •••••• ■••••• •••••• ■•••# — ••* ■••••# ••••• ••••• ••••i ••••• -••••• •••••• ••••• •••••• <••••• •••••• •••••f •••••• •••••• •••••• •••••• ■••••• ••••• ■••••• •••••• ••••• ••••i ••••• ••••• ••••• ••••• ••••• ••••• :>* Circle 100 on inquiry card. BYTE September 1979 247 Computer Products i The €xicly SORC6R6R Flenbilty is the key. The Sorcerer Computer gives you the flexibility of using ready-to- run, pre-packaged programs or doing your own thing and personalizing the programs for yourself. Which ever you choose, the Sorcerer is the personal computer that speaks your language. The Sorcerer also provides full graphics capabilties. Each character, formed by an 8 i 8 dot cell, can be programmed as a graphic symbol set. High resolution (512 x 240 addressable points) gives a total of 122.880 locations tor super animation and extremely tight plotting curves. The alphanumeric set gives 64 x 30 characters on the video screen PART NUMBER: SYO-S016A With 16K of memory $1150.00 i mmmmmmmtmmmmmmmm I Rockwell Aim-65: The Head-Stan in microcomputers RKIM-1 compotible machine with on-board printer and o real key- boardl 1375.00 ui/IK ARM MSO.00 w/4K RRM 4K assembler/editor in ROM $80 8H BASIC in ROM: $ 100.00 Power Supply $59.95 Case of RIM-65 $49.95 Special Package Price: $599:00 AIM-65 I4K), Power SuoplV. Case, and 8K BASIC ROM NOVATION iCAT RCOUSTic modgm ^■^ Features Include: 300 Baud onnn fi nsuj er/Originote. S e " ' 03. Comes SI 89.00 Assembled ond Tested PROTO BOARD Includes gold plated fingers. S-100 size, holds 72-16 pin dips, accomo- dates all 8 thru 40 pin dip packages. Reg -S19 9S Special Prlce- $16.95 pART TSX-140B SD SYSTEMS SBC-100 An S-100 single Doard com puler Z-80 CPU wilh 1024 bylesolRAM 8lo32K bytes ol PROM Sertal I O porl Kit $239.95 fesserribjed $369.95 SD SYSTEMS Z-80 STARTER KIT Baied on the powerful Z80 CPU, this hit is an ideal Introduction to micropro- cessors, II has an on-board keyboard and display, plus cassette tape Interface and expansion provisions tor two S-100 connectors. This "Do-it-ail" Board will also program the 2716 2K EPROM Kit $249.95 Assmbld and Tstd $399 95 TEXTOOLZIP DIP* II men. Sockets 16 pin Zip Dip II S5.50 24 pin Zip Dip II 40 pm Zip Dip II $7.50 $10.25 INSERTION FORCE LEEDEX MONITOR • 12" Black ond While • 12MHZ Bandwidth • Handsome Plastic Case $139. rRSaO 1 APPLE 'SORCERER'TRS-BO'APPL JADE MEMORY EXPANSION KITS For TRS-80. Apple. & Exidy 4116'i Everything a person needs to add 16K ol memory. Chips come neatly packaged with easy to follow directions. In minutes your machine is ready for games and more advanced software. $82.00 HIGH QUALITY 13 INCH COLOR MONITOR!— Specially matched lor use with the TI-99/4 console. Uses a simple, sure hook-up. UP TO 72K TOTAL MEMORY CAPACTIY— 16K RAM, plus up to 26K ROM onboard, plus up to 30K ROM In Tl's Solid State Software Command Modules. 16-COLOR GRAPHICS CAPABIL- ITY- Easy to access high resolution graphics have special features that let you define your own characters, create animated displays, charts, graphs, etc. MUSIC AND SOUND EFFECTS— Provides outstanding audio capability. Build three-note chords and adjust frequency, duration and volume quickly and simply. You can build notes with short, straightfor- ward commands. Five full octaves from 110 Hz to beyond 40,000 Hz. BUILT-IN EQUATION CALCULA- TOR— Unique convenience feature helps you find quick Solutions to everyday math problems, as well as complex scientific calculations. TSCFIS INSTRUMENTS TI-99/4 HOM€ CO/WUT6H F€flTUR€S INCWD€ R COLOR MONITOR, 1 6H RRM M6MORV, SRSIC BUILT INTO TH6 CONSOie. RND TUJO COMPRCHCNSIVe MAN- UALS €ASV FOR THE Q6GINN6R - CHaieNG- ING FOR THe OPCRT. Programs are sealed securely in SOLID STATE SOFTWARE COMMAND MODULES. These ROM packs actually add memory to the TI-99/4 so that the console's memory can be utilized (or user input. The software applications are presently broken down into lour areas: 1) Home Management/Personal Finance. 2) Education. 3) Entertainment. 4) BASIC. SVO-8994R $1150.00 JADE SERIAL/PARALLEL I/O BOARD Features Include: S-100 Compatible ■ Two serial I/O Pons using software- programmable UARTS ■ One general purpose latched parallel I/O Port Ideal for printer Interlace or control ■ Switch selectable ■ On board "Kansas City" standard cassette Interface useable upto 1200 Baud, allowing storage of up to 180,000 bytes on a 30 minute audio cassette. Assembled and Tested Kit IOI-1040A, $179.95 IOM040K $124.95 Bare Board with Manual IQM040B $30.00 SVM-l Port Number:CPK-5002A $245 6502- BASED SINGLE BOARD COMPUTER WITH KEYBOARD/DISPLAY, KIM-1 HARDWARE COMPATIBLE. COMPLETE DOCUMENTATION. SVM-l CAS6. C-NX-000005 $39.95 THE BIG Z THE NEW Z-80 CPU BOARD FROM JADE Features Include: ■ S-100 Compatible, available in 2MHz or 4MHz versions. ■ Onboard 2708. 2716. 2516. or 2532 EPROM can be addressed on any 1K. 2K. or 4K boundary, with power-on jump to EPROM. ■ Onboard EPROM may be used in SHADOW mode, allowing lull 64K RAM to be used. ■ Automatic MWRITE generation it Iron! panel is not used. ■ On-board USART for synchronous or asynchronous RS232 operation (onboard baud rate generator). ■ Reverse-channel capability on USART allows use with buffered peripherals or devices with "not-ready" signal. 2MHz- BARE BOARD 4 MHz- tmru CPU-302O0B....S40.00 KifCPU-30200K. 2 lbs $149.95 Kit: CPU-30201K, 2 lbs $159.95 Assembled and Tested: Assembled and Tested CPU-30200A. 2 lbs $199.95 CPU-30201A. 2 lbs S209.95 - GRI KEYBOARDS Features Include: Full 128 character ASCII ■ Trl-Mode Mos encoding ■ MOS/DTL/TTL compatible output ■ Two-key rollover ■ Level and pulse strobe ■ Shift and alpha lock ■ Selectable parity ■ Positive or Negative Logic ■ All new OEM grade components ■ Gold contact, low bounce keyswithces ■ Rugged G- 10 printed circuit board ■ Custom 2 shot molded keycaps ■ Low power consumption ■ Optional numeric pad available ■ Custom enclosures available. Model 756A Assembled- KBA-30756A $79.95 Model 753K (53 Key, Teletype Keyboard with lower case) Kit- KBA-30753K $65.95 DB25-CONNECTORS DB25P- CND1251 $2.25 DB25S- CND1252 $3.25 DB25C- CND1253 (Cover) $1.50 RS232 Special: DB25P, DB25S, plus Hood only $6.50 (Pari Number: CND-1250) MICROPROCESSORS F80 $16.95 280 <2MHz) $10.95 Z80A(4MHz) $14.95 CDP1802CD $19.95 6502 $11.95 6800 $9.75 6802 $14.00 S008-1 $15.95 8035 $24.00 8035-8 $24.00 8080-A $10.00 8085 $23.00 TMS9900TL $49.95 8080A SUPPORT DEVICES 8212 $2.90 8214 $4.65 8216 $2.75 8224 (2MHz) $4.30 8226 $2.75 8228 $6.40 8238 $6.40 8243 $8.00 8251 $7.50 8253 $20.00 8255 $6.40 8257 $18.00 8259 $18.00 8275 $51.20 8279 $17.70 USRT S2350 $10.95 UARTS AV5-1013A $5.25 AY5-1014A $8.25 TR1602B $5.25 TMS6011 $5.95 6800 PRODUCT 6821P $5.25 6828P $9.50 6834P $16.95 6850P $4.80 6B52P $5.25 6860P $9.25 6862P $12.00 6875L $7.30 6880P $2.50 CHARACTER GENERATORS 2513 Upper (1-12+5) $6.75 2513 Lower (1-12+5) $6.75 2513 Upper (5 volt) $9.75 2513 Lower (5 volt) $10.95 PROMS 1702A $5.00 2708 $9.95 2716 $49.95 2716 (5v) $49.95 2758 (5v) $30.00 DYNAMIC RAMS 4115 $5.00 416D/4116 (200m) $12.50 2104/4096 $4.00 2107B-4 $3.95 TMS4027/4096 $4.00 STATIC RAMS 2114 (450ns) 2114 (300ns) TMS4044/ MM5257(4S0m) $8.00 TMS4044/ MM52S7(300m) $9.95 21L02 (450m) 21L02 (250ns) 4200A (2O0m) 410D (200n>) 1—15 $8.00 $9.00 $1.50 $1.75 $9.95 $8.25 16—100 $6.95 $8.00 $7.50 $8.75 $1.20 $1.50 $8.50 $7.00 248 BYTE September 1979 Circle 195 on inquiry card. £ PfilCeS GOOD IN TH€ UN[T€D SW€S AND CANADA PI Af^E HCnCDC THl I CDCC. 800/421 -5«0» Continental U.S. L f\\-r C UnUt rSO I vLL rntt- 8OO/262-1710 Inside Calltomla ULIhen visiting the Los Angeles areo, visit JflD€'s retail store at 1 3340 S. Houjthorne Blvd. in the city of Hoiuthorne 1 INTEGRAL DflTfi SVST6MS MOD6L 440 PRINT6R TH€ PflP€R TIG€R ,Uptol98CPS $99500 I 1.75" to 9.5" Adjustable Tractor Feed I Parallel and Serial Interface I 96 Character ASCII Set I 1 32 columns- 6 or 8 lines/inch I Gight software selectable Character sizes I 1 10, 300. 600. 1200 Baud Rate fOfl THC- GRAPHIC OPTION WITH 2K. HDD J 199 00 Part Number: PRM-33440 MEM-2 16 K Static RAM Board KM- (450ns| $250 00 Kit. (250ns) $285 00 Assembled- (450ns) S325 00 Assembled- (250ns) S350 00 DYNAMIC RAM BOARDS EXPANDABLE TO 64K 32K VERSION. KITS JSei Dili 18Kxl, 2b0ns) Dynamic 3AM's, can oe expanded in 8K rements up to 32K 8K J159.95 24K $249 95 16K $199.95 32K $299.95 64K VERSION. KITS -K.es 4116 (16Kx 1. ?00ns) Dynamic HAM's, can De expanded in 16K ncrements up lo 64K 16K $249.95 32K $369.95 48K $469.95 64K S569.95 DIP SWITCHES Pari No. positions 1-9 SWD-103 3 $1.18 SWD-104 4 $1.20 SWD-105 5 $1.24 SWD-106 6 $1.28 tft-tftftftftftftftf SWD-107 SWD-108 SWD-109 SWD-110 »l.30 $1.34 $1.36 $1.38 CABLES STATIC RAM BOARDS JADE8K Kit5: 450ns $125.95 250ns $149.75 Assembled & Tested: 450ns $139.75 250ns $169.75 Bare Board: $ 25.00 32 K Static Assembled & Tested: 250ns 450ns 250ns Kit $795.00 $725.00 $575.00 L.S. Engineering EPROM Eraser Features Include: Erases up to 48 I.C.s at a time • Uses popular (and readily available 12* shortwave UV bulbs) ■ Handsome smoke-plastic case • Includes bulb • Just plug It in and you're ready to go! XME-3200, $39.95 POUU6R supples 'SD-249A For a Single 5 1 4 Disk rive By Power-One or Alpha Power +5V it,7A, +12V at 1.1A . . $52.00 PSD-205A For Single B Disk Drive By Power-One SV al 1A 5V at 5A. 24V at 1 5A S89 95 PSD-206A For Two 8 Disk Drives By Power One or Alpha Power 5V 2 5A 5V at 5A 24V at $125 00 Rockwell Aim -65 Power Supply PSX 030A S59 95 KiM i or SYM-1 Power Supply PSX-020A $*9 95 MINI-DISK CABLE KIT: To conned two 5 1/4" drives to disk controller board. Contains assembled and testec 5' long signal cable with 34 pin edge connectors. Also includes cables and connector tor D.C. power supply. WCA-3431K $34.95 8 DISK CABLE KIT: To connect two 8' disk drives lo edge-type controller (e.g.. Versalloppy. Ooubic-D) Contains assembled and tested signal cable wilh connectors plus cable and connectors (or both A.C. and D.C. power. WCA-5031K S38.45 8 DISK CABLE KIT: Same as WCA- 5031K except controller end ol signal cable uses Header" lype connector, e.g.. tor Tarbell Controller. WCA-5032K S38.95 SIGNAL CABLE ONLY: For one 5 1/4" drive to edge type controller connector (e.g.. TRS-B0 to Vista Disk Drive). WCA-3421A J24.95 Same as Above, except tor two 5 1/4" drives. WCA-3431A S29.95 JflD€ FLOPPY" DISK SPeCIAl INCLUD€S: ■ Two Siemens/GSI 8" Floppy Dish Drives ■ Power Supply ■ .lode Double Density Board (Kit) ■ CP/M T " Operating System with Basic 6 (CP/M is a registered trademark of Digital Research) ■ Package of 10 Blank 8" Diskettes (Double Density) ■ Interface Cobles. IF purchased seperately this package would cost: $1 544.95. JfiD€ SP€CIAl $1225.00 JADE ISO— BUS MOTHERBOARDS Cornel In either 6, 12, or 18 slot sizes. These boards with , a special ground plane assure a silent operation JADE 6 Slot Kit $49.95 Assembled $59.95 Bare Board $24.95 JADE 12 Slot Kll $69.95 Assembled $99 95 Bare Board S39.95 JADE 18 Slot Kit $129.95 Assembled $149.95 Bare Board $59.95 THE PIGGY MAINFRAME This steak new mainframe Is neatly trimmed to hold six S-100 boards, three mini-floppy drives, and is available In five colors. Power requirements: 115/220 VAC, 50/60 HZ. Weight: 27 lbs. (with drives). Dimensions: 21 .375" Wide X 8.4" High X 1 5.675" Deep. Power Supply: 8 volts at 16 Amps unregulated, + 16 volts at 3 amps unregulated,- 16 volts at 3 amps unregulated, + 5 volts at 3 amps regulated, + 16 volts at 3 amps regulated. THE PIGGY IS HERE! THE PIGGY (Without Drives). . . PART NUMBER: ENS-106320 S475.00 spezini 5'A" Diskettes $29.95/Box of T€N SPeCIFV SOFT, 1 0. or 1 6 S€CTOR 8" SINGL6 SID6, SINGL6 DENSITY $34.95/Sox of T€N TH€ JAD€ "DOUBl€-D" INT6LLIG6NT DISK CONTROLL6R ■ READ WRITE IN SINGLE OR DOUBLE DENSITY ■ X" or S'/i" DRIVES ■ CP M COMPATIBLE IN EITHER DENSITY ■ ONBOARD ZK0 CPU ALLOWS UNIVERSAL SYSTEM COMPATIBILITY ■ PROGRAMMED DATA TRANSFER -NO DMA ■ CONTROLS UP TO S DRIVES ■ SOU WARE SELECTABLE DENSITY Our new controller utili/cs the IBM standard formats for proven reliability. -Data recovery is Cnchaccd through use of a phase-locked-loop data sepcralion circuit and write precompensalion. Single and douhle density diskettes can he mixed in the same system. Assembled and Tested IOD-I200A. 2 lbs. .. $299.95 Kit 1OD-I200K. 2 lbs. .. $249.95 Bare Board w; Manual IOD-I200B. 2 lbs. . .. $55.00 Manual IOD-1200M. I lb. ... $10.00 Computer Products ■"■ 4901 W ROSECRANS AVE.. HAWTHORNE, CALIFORNIA, 90250 (213)679-3313 ORDER TOLL FREE 800-262-1710 pm 800-421-5809 INSIDE CALIFORNIA ||§|j, CONTINENTAL U.S. WRITE FOR OUR FREE CATALOG Cash, checks, money orders, and credit cards accepted. Minimum order $10.00, California residents add 6% sales tax. Minimum shipping and handling charge: $2.50. Discounts available at OEM quantities. PflK€S SUBJ«T TO CHHNG€ WITHOUT PflrOfi NOTKC For fetport information send for a JflD€ IOT€ftNATIONAl CATALOG VB-1B VIDEO INTERFACE S-100 Compatible Serial Inter- face with Sockets Included. Kit $117.95 Assembled & Tested $159.95 Bare Board w/manual s 35.00 FLOPPY DISK INTERFACE JADE FLOPPY DISK (Tarbell board) JADE KIT $190.00 Assembled & Tested $260.00 S.D. Computer Products VERSA-FLOPPY K " S15995 Assembled 8, Tested S2 39 00 DISK DRIVES MPI B51 5 1/4 " MSM-1SS10O $295.00 Single or double density, up lo 40 tracks, track to track access time only 5ms. MPI B52 5 1/4" HSM-15S200 . $450.00 Double head version ol MPI B51 Shugart SA400 5 1/4" $325.00 Single Density, 35 Track Siemens FDD100-8 8" $495.00 Shugart 801 R replacement, Single or double density, runs cooler and quieter. Siemens FDD200-8 8" $575.00 Double head version ol FDD100-8 capable of double density, double sided storage. Shugart 801 R 8 "... $575.00 Hard or solt sectored, 400K BYTE drive. vista V80 mini dish SYSTEM FOR TRS—80 $395.00. PART NUMBER: MSM-35S000 Includes disk drive, power supply, regulator board, and compact case The V-80 often 23% more storage capacity. Simply lake it out of the box, plug in the cable, and it's ready to run Requires 16K. Level II. eipanslon interface. Interface Cable . . $24.95 PART NUMBER: WCA-3421A Circle 195 on inquiry card. BYTE September 1979 249 Circle 296 on inquiry card. COMMERCIAL GRADE PERIPHERALS FOR THE MICROCOMPUTEI PRINTER TERMINALS • '*» » I MODEMS TAPE DRIVES •ASCII SELECTRIC PRINTER/TYPEWRITER: Why settle for less than letter-quality printout from your computer? Refurbished IBM Model 725 can be used as off-line typewriter or on-line printer. Complete with solenoids, power supply, case and ASCII interface card (TTL to CPU parallel port.) Interface includes programmable ASCII translation table on EPROM with up to 8 tables for use with various type spheres. Feedback signals on completion of each print cycle insures fastest printing speed (15 cps.) Price: programmed w/3 translation tables (one type sphere): $795.00 •SELECTRIC I/O TERMINALS (by GTE/Information Systems). Both ASCII & IBM code versions with microcomputer interface software & hardware (RS- 232 connector.) Cassette drive models permit up to 2400 baud data transfer rate as well as off-line data storage, use as memory typewriter, & use as data entry device for office personnel familiar with Selectrtc typewriters but not computers. Wide-carriage, interchangeable type spheres; optional built-in modem. All units cleaned, adjusted & warranted. Model 5541 (IBM Correspondence code) $795.00 Model 5550 Icorres. code, built-in cassette drivel $1195.00 Model 5560 (ASCII code, built-in cassette drive). $1295.00 •DIABLO MODEL 1550 "DAISY-WHEEL" TERMINAL: Refurbished letter-quality terminal with Hytype I printer (30 cps), full ASCII key- board, RS-232 serial prot, 110, 150, 300 baud, 768 char, print buffer, software controlled graphics mode (1/60 in. spacing), built-in stand. SHIP WT. 200 lb. Price, refurbished: $1895.00 • DIABLO HYTYPE I Model 1200 PRINTER MECHANISM: used, complete and tested. Requires power supply, case & mCPU interface. 15 day return privilege - no other warranties. LIMITED QUANTITYI $750.00 —6' Ribbon cable & connector for printer Main Logic PCB $10.00 —14-pin Winchester connector & 18" power supply cable $5.00 -"As-is" spare printer PCB's for parts (Logic, Heat Sink, Control): ea. $20.00 -New Pin-feed Platen (14"): $50 if bought w/printer; separately . . . $100.00 • POS 103/202 "MIX or MATCH" MODEM: BELL 103 and/or BELL 202 FREQUENCIES: Unique POS control design permits use in one housing of both Bell-compatible 103 (0 - 300 baud) and 202 (0 - 1200 baud) modem modules originally made by VADIC Corp. for a telephone company subsidiary. FEATURES: RS-232 serial interface, auto-answer, auto-dial, LED display, telephone line interface via acoustic coupler, manual DAA, or auto-answer DAA (sold separately.) FULLY ADJUSTED; no special tools required. 3,000 mile range over standard dial-up telephone lines. -POS 103 MODEM (with Auto Answer, Auto Dial). $179.95 -POS 202 MODEM (Half-Duplex with Reverse Channel) $249.95 -POS 202 MODEM (Half-Duplex w/Rev.Ch., Auto-Answer) $279.95 -POS 103/202 MODEM (Auto-Answer, Auto-Dial) $399.95 • POS-100 NRZ1 TAPE DRIVE CONTROLLER/FORMATTER: Designed as interface between S-100 bus mCPU and 9-track, 800 BPI, NRZ1 tape drive. Allows microcomputerist to read and write IBM-compatible %" mag tapes. Software provided for 8080 or Z-80 systems. Requires modification for drives of various mfrs. Price: (Includes S-100 card, controller card, 10' cable, software listing) . $750.00 •NRZ1 TAPE DRIVE by WILLARD LABS. 9-track, 800 BPI, NRZ1 format, 12"/sec, 1200 ft. reels (10 megabyte capacity) Fully tested and warranted $599.00 •CONVERT 15" IBM OFFICE SELECTRIC TO I/O TYPEWRITER: Kit includes assembled solenoids, switches, wire harness, magnet driver. PCB plus instructions for installation and mCPU interface $200.00 • DIGITAL CASSETTE DRIVE (from GTE/IS Terminal): 1800 baud, 6"/sec; AC motor; fwd/rewnd circuitry plus tape head, no read/write electronics $25. •FORMS TRACTORS, Moore Variable width "Form A-Liner" for print terminals: alModel 565P for 15" Carriage IBM Selectrics (new): $75.00 bIModel K81 for QUME or DIABLO Hytype I or II printers (new): .... $90.00 •POWER SUPPLIES for Disk Drive, mCPU, tested under load shown: -No. 519 Iw/fan & AC cord): +5V reg., +12V reg., +24V, @4A (10 lb.) . .$39.95 -LAMBDA No. LMEE5w/OV protect: +5V reg. <§> 25A (35 lb.) $69.95 __^ __________„ no RISKI 15 DAY APPROVAL ON ALL MAIL-ORDERS — ^— Full documentation included PLUS interface instructions K PACIFIC OFFICE SYSTEMS, INC. & Call or write for details, quantity prices, catalog. 15day ra 918 Industrial Ave. V Palo Alto, CA 94306 '\ (415)321-3866 where indicated. All equipment is shipped insured FOB Palo Alto within 14 days after check clears or COD order is received. Prices may change without notice. return privilege PLUS 90 day no charge replacement of defective parts. All orders shipped from stock. No back orders, no substitutions. M/C & VISA accepted. ProComp/New England 9Z C micRomflTion ) Specli 'ah announces IMNET ... (IMSAI Multi-user NETwork Operating System) True Microcomputer Networks.... Better than timeshared mini- or micro-systems.... And less expensive. Stop by and see for yourself, Or write or call for our IMNET brochure. 10 Megabyte Winchester Disk, Integrated Video Computer... $10,995. Other Micromation Integrated Video Computer Systems from $5995. Micromation Doubler Disk Controller. ..$395. 'Measurement Systems & Controls 48K Dynamic Flam. ..$595. (617)482-4450 120 Boylston Street 4th Floor Boston, MA/02116 Write, call or stop in (M-F 9-5; S 10-4) for our catalog and Grand Opening Sale Price List. ProComp/New England 250 BYTE September 1979 -page- Wire Wrap Tools c* sfr* BATTERY HOBBY TOOL* • Auto Indexing • Anti-Overwrapping • Modified Wrap BW2628 Tool $19.85 BT30 #30 Bit 2.95 BT2628 #26 Bit 7.95 BC1 Batteries & Charger. . 11.00 'Requires 2 "C" Niced Batteries BATTERY INDUSTRIAL TOOL* • Accepts Industrial Bits and Sleeves (Gardner Denver or equiv.) • Industrial Motor for Production Wire- wrapping • Backforce Avail. (Recommended for #30). ELECTRIC INDUSTRIAL TOOL • Accepts Industrial Bits and Sleeves (Gardner Denver or equiv.) • Industrial Motor for Production Wire- wrapping • Backforce Avail. (Recommended for #30). BW928 Tool 49.95 BW928BF Backforce Model 52.95 EW8 Tool . 85.00 Bit & Sleeve Specify #22-#30 29.50 EW28F Backforce Model . . . 92.90 BC1 Batteries & Charger. . 11.00 Bit & Sleeve #22 or #30 . 29.50 RN HIGH RELIABILITY eliminates trouble. "Side- wipe" contacts make 100% greater surface contact with the wide, flat sides of your IC leads for positive electrical connection. IC Sockets WIRE WRAP SOCKETS 3-level Gold Closed Entry Design All Prices Include Gold. 2-level Sockets Also Available 1-9 10-24 25-99 100-249 250-1 K 8 Pin 14 Pin 16 Pin 18 Pin 20 Pin 22 Pin 24 Pin 40 70 .90 .95 .95 25 Pinst 1.25 28 Pin 1.25 40 Pin 1.65 36 .39 .42 60 .80 .85 .85 .15 .15 1.45 .34 .37 .40 .55 .75 .80 .80 1.00 1.00 1.35 .31 .34 .36 50 .65 .70 .70 .95 .95 1.20 .27 .32 .34 .45 .62 .65 .65 .90 .90 1.10 SOLDER TAIL Low Profile Tin 1-9 10-24 25-99 100-249 250-1 K 8 Pin .21 .18 .16 .15 .14 Closed Entry Design 14 Pin 16 Pin — .19 .21 .17 .19 .15 .13 .17 .15 18 Pin .30 .28 .27 .26 .25 20 Pin .35 .34 .33 .32 .31 22 Pin .36 .34 .30 .27 .26 24 Pin .38 .36 .32 .29 .28 28 Pin .45 .44 .43 .40 .39 40 Pin .63 .62 .61 .58 .57 OK PRODUCTS WD 30 50 ft. Wire Dispenser, Red, White, Blue or Yellow $3.75 WD-30-TRI TRI Color Dispenser 5.50 R-30-TRI Refill for TRI Color 3.75 INS 1416 14 & 16 pin Insertion Tool 3.25 MOS40 40 pin Insertion Tool 7.50 EX-1 IC Extractor Tool 1.49 H-PCB-1 Hobby PC Board 4.99 WSU30 Hand Wrap/Unwrap/Strip Tool 6.25 WSU 30M Same as WSU 30 with Modified Wrap 7.50 AVAILABLE AT page ORDERING INFORMATION • Orders under $25, add $2 handling • Blue Label or First Class, add $1 (up to 3 lbs.) • CODs, VISA & MC orders will be charged shipping • Most orders shipped next day. 135 E. Chestnut Street 5A, Monrovia, California AT SELECTED LOCAL DISTRIBUTORS Circle 299 on inquiry card. 91016 Phone (213) 357-5005 BYTE September 1979 251 *v^; STATICW/RAM BOARDS. nesPt S-100 32K (uses 21 14) ASSEMBLED 450ns. 599.00 450ns. ' 539.95 250ns. 699.95 250ns. 599.95 Bare Board 49.95 Bare Board w/all parts less mem. 99.95 8-1 00 1 6K. (uses 2 1 1 4) KIT (exp. to 32K) 450ns. 250ns. ASSEMBLED 450ns. 325.00 250ns. 375.00 Bare Board 49.95 LOOOS I 8K ASSEMBLED 450 ns. 169.95 KIT 450ns. 125.95 250ns. 189.95 250ns. 149.95 Bare PC Board w/Data $21.95 Now over 1 year successful field experience -Special Offer" Buy (4) 8K 450ns. Kils S 1 1 7.00 FLOPPY DISK DRIVES 1. VISTA v-80 MINIDISK FOR TRS-80 * 23% More Storage Capacity - 40 Tracks * 40 track patch now avail.^*—" ~^v * Faster Drive - f, -__ -_\ Up to 8 Times Faster l*"*WJ 2 Drive Cable Add $2995 > ' 4 Drive Cable Add $39.95 2. VISTA V-200 MINI-FLOPPY SYSTEM * 204K Byte Capacity -k w/CP M. Ba sic "E" •k Double Density Drive f -*^ * One Double Density I W-200 \ Controller w/Case & P.S. V 6e8 -° / Add to your EXIDY, HORIZON, and other S-100 computers. 3. VISTA V-1000 FLOPPY DISK SYSTEM * (2) Shugart 8" Floppy Disk s , * Controller Card, Cable. jC7~5&. Case i P.S. CtlSSSS * CPM & Basic "E", UeBS.0O/ Instructions* Manual ^■— S 4. MPI B51 -5V. 40 tracks 279.00 5. Shugart SA400-5W, 35 tracks. . . . 295.00 6.Siemens/GSIFDD1 00-8 8" 375.00 7. Shugart 800/801 fl 8" 495.00 8. PERSCI Model 277 Dual 1195.00 9. WANG0/8IEMENS 5V Drive . . . 290.00 EXPANDORAM MEMORY KITS * Bank Selectable * Uses 4115 or 41 16 200 ns. * Write Protect * Power 8VDC. ±1 6VDC * Phantom * Lowest Cost/Bit Expando32Klt(4115) Expando64Klt(4116) 8K $158.00 16K $248.95 16K $199.00 32K $369.00 24K $299.00 48K $469.00 32K $349.00 64K $565.00 IMS STATIC RAM BOARDS j,? * Memory Mapping ir Low Power r^ * Phantom * Assembled & tested Recommended by Alphamlcrosystems 250 ns. 450 ns. 8K Static $209.00 $189.00 16K Static $449.00 $399.00 32K Static $799.00 $699.00 ANADEX PRINTER Model DP-8000 compact, impact, parallel or serial. Sprocket feed, 60 cols, i 84 Ifnes/min., bi-directional New only $895.00 VERBATIM" DISKETTES >tl * 5*" Minidiskettes • &&£ Soltseclor , 1 Sector, 1 6 Sector' •W.-rt $4.25 Each, 10/39.95 nM^iwS * 8" Standard Floppy Olsks * TaY* I Soft Sector, Hard Sector V $4.50 Each, 10/41.95 •Add 4.95 for 1 Pack in Deluxe Disk Holder l EXORCISM COMPATIBLE 9600 MPU Module w/6802 CPU $495.00 9601 18 Slot Mother Board 175.00 9602 Card Cage (1 9" Retma Rack Mount) ... 75.00 9603 8 Slot Mother Board 100.00 9604 Switch mode System Power Supply . . . .250.00 961 Utility Prototyping Board 36.00 9616 Quad flK Eprom Module •"" 9620 1 6 Channel Parallel I/O Module .... 295.00 9622 Serial/Parallel I/O Combo •*• 9626 8K Sialic RAM Module 295.00 9627 16K Static 460ns 495.00 9630 Card Extender 68.00 9640 Muttiple Programmable Timer (24 Timers} 395.00 9650 8 Channel Duplex Serial I/O 395.00 96103 32/32 I/O Module 275.00 96702 32 Point Reed Relay Module 350.00 eaOO BARE BOARDS 9620-0 $45.00 9603-0 27.00 9626-0 45.00 9600 56.00 9650-0 45.00 96103 -.55.00 9601-0 60.00 96702 55.00 Also AMI EVK System In Stock APPLE/EXIDY/EXPANDO TRS 80 1 6K-UPGRADE KIT * IbK wiln Jumpers & Instructions for either Level t or Level II $74.95 * 16K for Apple II Upgrade $74.95 Special: TRS80 Schematic S 4.95 Expansion Interface Schematic $ 4.95 TRS 80 TO S-100 PET TO S-100 ADAPTER Allows Pet/TRS 80 to be interfaced to popular S-100 Bus. Pet to S-1 00 Kit $1 89.95 Assembled $269.95 TRS80toS-10O HUH 8100 Kit .... $275.00 Assembled $355.00 KEYBOARD ASCII ENCODED One time purchase of NEW Surplus Key- boards. From the Singer Corporation. The keyboard features 1 28 ASCII characters in a 63 key format, MOS encoder circuitry "N" key rollover, lighted shift lock, control, escape and repeat functions. Ltd Qty <*3 KEY $69.95 UV "Eprom" Eraser ~ M» 7.75 Intro to Micro* VOL I £*v 7 75 8080A Programming J6Q 7.75 6B0Q Prog ram mlng . 'B9 '■"* ZBO Programming. e'SQ 7.75 Vol. II Some Real MMOprocaaaooi w/Btnder . .TrXJQ 27.50 Vol. Ul Soma Real Support Device* w/B-nder . TQ-eo. 18 90 Intro lo Micros Vol III TtHtO. 1B.SO •AIR a MUTHIUH COMHmR MOKI a le\L> Undemtandtnfl Compoler* "B.96- 7.B5 aoeoMteiocompu'e. Etpartmanta. . . . TSteV 11.95 Beginning BASIC ... »•*. 8.95 Beginners Qtouary 6 Quick* SW 5.05 Psanul Butler 1 Jely Guide lo Compute™ TM. S.05 0080 Machine Language Programming .T .0 5. 8.95 Home Compulera Vol I Hardware . . . . . . ... . -TAt 8.B5 Home Computer* Vol. " Software ,. . ... *t»«f> 11.95 THE FIRST TO OFFER PRIME PRODUCTS TO THE HOBBYIST ^ AT FAIR PRICES NOW LOWERS PRICES EVEN FURTHER! 1. PrOVCIl QtlSllty Factory tested products only, no re tests or fallouts. Guaranteed money back. We stand behind our products. 1979 CATALOG NOW AVAILABLE. Send $1.00 for your copy of the most complete catalog of computer products. A must lor the serious computer user. MICROPROCESSORS STATIC RAM HEADQUARTERS SOCKETS ZflOOO ... 2-110 2-aoA F-8 I3U50) 2650 C0 1802 3901 2901A IMS 9900JL CP1600 5502 6902A IM6100 5500 6802P 8035 8755 8748 6809 ..SCALL I4.M 18.95 .. 13.95 . 24.95 19.95 .49 95 6995 ..I CALL ..SCALL SUPPORT DEVICES AM95UAr,ih Pro. .",•-. -■' AM 9511-1300 na AM95T7 OMA Conlrollet 3881 1280 PIOl 38S1-4I4MHH 3BS2 IZ-BOCTCl 3882-4 I4MHH 3883 510 3884 DMA 820&/74S13B Decode' S2i2 8b.ll/0 S2i4Pno»1ymi 8218 But Driver 8224 Clock Gen 8224-4 (4MHi| B226 Bui Driver BI26 Bui Omre. 3228 Sys Control S23B Sys Conl 8251 Prog I/O B253 mi Time' 8299 Prog I/O 8357 Prog DMA 8259 Prog Inl fl27SCHTConlio[ief 8279 Prog Keyboa-d . 6810-1 128 « 8 RAM 6620 PIA 6821 PIA 5828 Priority Int. 6834-1 512*8 Eprom 6850 AClA 6852 Serial Adlpler 6fl45'HD46505CRTC->nl 6860 Modem 6862 ModtrUjior 6871A 1 OMHrOSC 2 50 4.50 250 2 95 9 75 395 239 595 625 49.09 18.06 4.75 595 6.90 695 25 95 8 25 2 39 1-24 25-99 100 1 30 125 21L02 250ns 1 69 1 55 145 2102 125 1 15 1.10 2111 3 75 3.65 3.55 2112-1 295 2 85 2.65 2.70 255 2ll4L-260ns. 12 95 995 21 14L-300na 895 7 95 645 JI14L-450r.S. 750 575 4.73 4044/404 1 300ns 995 8 75 795 4044/4041 490ns. 7.50 675 4.T5 EMM420OA 975 8 75 7 95 EMM4402 7.25 6 25 EMM4804 1250 11 SO 995 7 95 7 95 7 25 upd4IOI4200. 10 95 1025 9 25 AMOOI 40/41 10 95 1025 9 25 AMD9 130/31 12 95 11 95 10 25 FSC 460/464 1 6« CCD Only 9 895 Each 1101 < 95 P212.V93425l46n-, 1 7 95 7 35 7 25 9508 IKil CMOS 7 95 7 95 7 25 6518 IK a 1 CMOS 7 95 7.95 725 745189 54 Oil Ram 3 95 325 250 2i47LowPowe>4XSta|fc 14 Seat CHARGE COUPLED DEVICES 16KCCD ■Firsllimoc 'tared Fa rchild 460 CCD 16K Memory (now yo -iCCO lochnology al a reasonable pnci 17 page Apples. iKhordi iim.ied) $18.95 •«ch (rejg. 43.00) 25 00 6880 Bus Driver MC6B48B 1821 SCO IK RAM 1822 SCO 256 ■ 4 RAM 1824 CO 32 i 8 RAM 9 95 1852 CD B oil I/O 10 95 1854 Uarl 10.95 1856 CD I/O . . . 895 1857 CO I/O 8 95 6920 PIA 7 90 6522 Mull 9 25' 6530-002 . IS 50 6530-003 . 15 50 6530-004 15 50 6530-005 .15 50 DYNAMIC RAMS 416/4118 18K(i8Pln| . .... g.Q5 Selol84l8't 74.95 41 IS 8K [16 Pin) 6.95 4050 ik ■ 1 (ISPmi) .425 I (2? Pin) 4 95 I {IS Pin) . . 3 95 i (IflPin) 4.78 i I (16 Pin) 4 95 4050 4K> 4096 4K i 2104 4K. 4027 4Ki 5261 195 6262 . 195 5270 ...495 5280 a 95 5290 12 45 PROMS 2708 2708-6 1702A 2732 1103 . 4008L 6-5V 12V 2513-001 (5V) Upper ..950 2513-005 |5V) Lower . 10 95 2513-ADM3I5V) Lower 14 95 MCM6571A MCM6574 MCM6575 . 14 50 UARTS/USRTS 7RI602BI5V, 12V) . . Ay510l3(5V. 12V) 4.99 AV51014A/I6I2I5-14V1 . AY51015A/186.1[5V| IMS 6011 (5V. 12V) 1B71BAslro« . 2495 ..B.B3 BAUD RATE OEM WDH 9 95 KEYBOARD ENCODERS AY52376 13 75 AYS-3600 .1375 HD0169 9.95 74C922 9.95 74CB23 B.U A/D CONVERTERS 8700 8 nil Binary. 8701 10 bl Binary 8703 8 :■'■■ TS 9400 Vmi lo F'ag Conv. B750 3-1/2 Digit BCO 140HL6 6oi! . ..... 1408L8 8DI1 . DACOlA/D 13 50 22.0C 1350 22 P.n 51 n TEXTOOL ZERO INSERTION FORCE SOCKETS 16 Pm S 5 50 24 P-n S7 I 40 Pin 110 25 CONNECTORS DS2SPIRS232I DB25S Female Hood. Scrl w/Hood. Sale 22/44 WAV. S/T, KIM 43/86 W/W. S/T, MOT .. 50/100 S-100 Connodo' » 50/t00 S-100 Connector u 55 50 2 95 650 CTS DIPSWITCHES CTS206-4' 51,75 CTS206-8 5195 CTS206-5 SI 75 CTS206-9 Si 95 CIS2056 Si 76 CTS206-I0SI9S CTS206-7 SI 75 CRYSTALS attcroprocaaae* TI Price S5 85 > 8433 4 95 5 85 2 0IMH/ 295 2 097152MIH 585 2 4S76MHt 3 571545MH/ 150 4CMM/ 4 96 4 I94304MH/ 595 4 9I520MH* 5 95 SOMIU 4 95 5 06B8 3.'U3MHi 5 95 6 5536 10 0MHz 13 0MHz 18 0MHz 13 432MHz 20 0MHz 22 1 184 MHz 27 0MHz 36 0MHz 48 0MHz 10OKC DISPLAYS/OPTO/LED'S * THOMIfaT * CALC * CLOCK* * DL 704 (CO, OL 707 (CAl 300" Red. 99 FND 357 (CCI 357" Red 9S FND 500/503 (CO SOD - Red 99 FND 507/51 0(CA| 500" Red . .... ... 90 FND BOO/803 (CO 800' Red 1.7S FND 807/810 (CA) 800" Red 1.7S XAN 3062 .SOO" Q'oen 1.15 HP506 2-773 HCA) 300* Red 99 9 Dflii Bubble Mini Cale Ditpiey ....99 9 Digi! Panapiea DhUtaY 400* 9B 9 Digll Fluorescanl 300' 33 MAI003 12V Auto i:n»fc Module II 96 BdieMo'MAI003 w/Red Filter J 35 MA1002A LED 12 nr. Clock Module 1095 * H«X ENaWLAYt • IMCOOCO DISMJtrt * HP 5062-7340 Red Handecmal 1536 HP 50827300 Red Nymenc 1446 TIL 308 Numeric w/Logic &M TIL 308 Number w/Loglc 10 5 TIL 309 Number w/Logie aos TIL 311 Ha»adeom»i 12-tW MAN 2A . 320" Red Aipna Numeric. 9*5 MAN 10A.270'Red AjphaNumenc B.99 NAKED PC BOARD SALE z-aocpu iiiMcii .. 6O80ACPU BK Sine RAM (Logcil 16K Stain: RAM (2114) 32K Sialic RAM (2114) Floppy i/O aarbem... Caiaelle t/O (Tarbell) BKEprom|2706| 1702 Eprom Board... 270672716 Eprom (tmacaj. . 34 95 2706/2716Eprom(WMC) .30.00 nealiime Clock 34 85 ACPProtoBd.(3MConn. Veclor 8800 Proto ... . Wee lor 8803 1 1 Slot MB ACP Emender w/Conn Video Interlace (SSMi Parallel Interlace ISSM1... 27 95 lSSIolMolherBoartJIWMCl 32 95 SSIOIMolhorBoardfWMC) .2995 8 SKjlMolnerpn panOa&ei 3495 S34 95 34 95 2195 2P95 4995 39 95 29 95 21 95 30 OC 19.95 29 95 15 95 27 95 WAVEFORM GENERATORS 8038 Funcl^nC MC4024 VCO LM566 VCO KH.-206Fune1ic Gem FLOPPY DISK I/O 1771-01 8' « Minifloppy uPrj372 Nac Floppy 1781 Dual Floppy 1791 Dual Floppy TV INTERFACES PiiM-Verter TV- 1 Video Interface Mooverler MAR Modulator 49 95 2995 39 95 650 8 99 -35 00 3500 2716-51 2758 5V 5203AO 1 1 95 5204AO 995 6834-1 1295 IM 56 10 2 95 ■ALE MM S* l • l.M 62S1 15 61 2 i B CTS) . 16.95 823 123 32 ■ fl 2.50 B2S126 258i4 3.50 825129 256* 4 ITS) 3.60 B2S130S12i4(OO 6.50 NSC DM7578 32 * 6 3.95 CHARACTER OEN SPECIAL PURCHASE (while supply lasts) 21 L02-4 (450 ns) 100 @ 99$ ea. 21L02-2 (250 ns) 100 @ $1.15 ea. TMS4060 NL 4K Dynamic RAMS (pullouts) $1.95 ea. 1488 Line Receiver 100 @ 75$ ea. 1489 Line Driver 100 @ 75* ea. 1489 House Marked 100 @ 50$ ea. 1496 L Demodulator 25 @ 75 N 0) tow APPLE II PLUS $990.00 APPLE'S new upgraded APPLE II W/16K is now in stock and available for the lowest price ever, only $990.00. You can add: *• M & R Modulator for $29.95 ** Sanyo tape recorder for $44.95 •* 1 6K upgrade kit for only $74.95 ea. This isa limited offer and we reserve the right tochange without notice. NORTH STAR HORIZON ^oUILi density* Now in stock North Star Z-80-based high-performance computer, • 180K Bytes per Disk # Z-80 Processor • Motherboard * 2 Serial +1 Parallel Port Avail. * 16KRAM Horizon I Kit Reg. $1599.00 Sale $1349.00 Horizon II Kit Reg. $1999.00 Sale $1749.00 North Star Double Density Disk Subsystem Kit PROCESSOR TECHNOLOGY SOL-20 DEALERS & USERS INVITED! ***** We purchased Processor Technology's entire inventory of spare parts, work in process, and finished goods. This material will be sold on a first come first served basis. Advanced will continue to support some SOL products on a limited basis so make sure you get a copy of our complete inventory listing and a place on our SOL mailing list. • New SOL-20 w/o Memory • SOL-20 Keyboards • 8KRA Memory Boards Assembled • NKRA Memory Boardsupto64K $1295.00 $139.95 i $129.95 $CALL ' Plus more endless PTI bargains send for details. WE TAKE B/A, VISA, AM. EXP. • ADD 2.5% HANDLING & POSTAGE • PRICES SUBJECT TO CHANGE W/O NOTICE Circle 4 on inquiry card. BYTE September 1979 253 Widen the ability of your TRS-80 Vi/tol MM The Vista V80: $395 The Vista V80 Mini Disk System is the perfect way to widen the capabilities of your TRS-80* Micro- computer. Quickly and inexpensively. Our $395 price tag is about $1 00 less than the Radio Shack equivalent. Our delivery time is immediate (24 hour turn- around from our Santa Ana, Ca. factory). And our system is fully interchangeable. That's just the start. It will give you 23% more storage capacity by increasing useable storage from 55,000 to 65,000 bytes per drive with our new software patch. It can work 8 times faster than the TRS-80 Mini- Disk system, because track- to-track access is 5ms versus 40ms for the TRS-80. You can realize this added speed •TRS-80 ©Tandy Corp. 254 BYTE September 1979 once the new double disk expansion interface is available without expensive modification of the existing unit. It has a better warranty than any comparable unit warranty available - a full 1 20 days on all parts and service. When you consider how much more goes into the Vista V80, that shows a lot of faith in our product. A full 3 amp power supply means you have 2V2 times the power necessary to operate the V80, and full ventilation insures that there will be no problems due to overheating. The Vista V80 Mini Disk System requires Level II Basic with 16KRAM Expansion interface (it operates from the Radio Shack interface system. It comes complete with a dependable MPI Minifloppy disk drive, power supply, regulator board and vented case. It's shipped to you ready to run - simply take it out of the box and plug it in. You're in business. From the company that means business -Vista Computer Company. The Vista Computer Company. Manufacturers of Quality Computer Systems and Software. 714/751-9201 1320 East St. Andrews Place Suite I, Santa Ana, Ca. 92705 Circle 378 on inquiry card. The NEW Owners Of Radio Hut P.O. BOX 201 5 GARLAND, TEXAS 75041 ORDER BY PHONE— 214-324-5509 * ANNOUCE: THE RETURN OF RADIO HUT SUPER SPECIALS! The EXPANDORAM is available in versions from 16K up to 64K, so for a minimum in- vestment you can have a memory system that will grow with your needs. This is a dy- namic memory with the invisable on-board refresh, and IT WORKS! • Bank Selectable • Phantom • Power 8VDC, + 1 6VDC, 5 Watts • Lowest Cost Per Bit • Uses Major Brand 16K RAMS • PC Board is doubled solder masked and has silk-screen parts layout • Extensive documentation clearly written SD EXPANDORAM Complete kit includes all Sockets for 64K Memory access time: 375ns, Cycle time: 500ns. J • No wait states required |j • 16K boundries and Protection via Dip Switches • Designed to work with Z-80, 8080, 8085 CPU's EXPANDORAM 64K Kit (1 6K Ram) 16K $219.00 32K $279.00 48K $359.00 64K $419.00 WITHOUT MEMORY $159.00 We carry a full line of SD Systems Products. Please write for catalog or call for prices UNSCRAMBLER KIT Interfaces with any monitor or scanner • Easily tuned • Full instructions included • Drilled fiberglass PC. Board • One hour as- sembly • Easy to install • Punched case This unit can unscramble most any scrambled frequency such as the new Motorola scramble and so on. Only $37.95 A&T TELE TAPE Record important telephone conversations now with Tele Tape and your recorder. Each time your telephone receiver is picked up your recorder will start automatically and when you hang up it stops. Tape will be extra clear so you can refresh your memory at a later date. Kit includes everything except case and phono plugs. Assembled and Tested only $29.95 "VERSAFLOPPY" KIT The Versatile Floppy Disk Controller Only $139.00 FEATURES: IBM 3740 Soft Sectored Com- patible. S-100 BNS Compatible for 2-80 or 8080. Controls up to 4 Drives (single or double sided). Directly controls the following drives: 1 . Shugart SA400/450 Mini Floppy 2. Shugart SA800/850 Standard Floppy 3. PERSCI70and277 4. MFE 700/750 5. CDC 9404/9406 BOWMAR 4 DIGIT READOUT ARRAY 4 Jumbo .50" Digits In One ■Stick"! The Bowmar Opto-Stick. The best readout bargain we have ever ottered. Has (our com- mon cathode |umbo digits with all segments and cathodes brought out. Increased versa- tility since any ot the digits may be used inde- pendently to fit your applications. Perfect for any clock chip, especially direct drive units like 50380 or 7010 Also use in treq. counters. DVMs etc. For 12 or 24 hour format. (With colons and AM/PM indicator. I $1.99 I — lllltffffftttlt FLOURESCENT* READOUTS No. DG8F. Seven segments, blue- green in color. Can be directly driven by many MOS ICs. .3" character. .49 Ea. LEDS Jumbo Reds 10/S1.00 Jumbo Green & Amber 51 St. 00 U[ni Red S/St.00 Mini Green, Amber St Clear 6/S1.00 LED WIRING HARNESS* A $10 VALUE! Has one of our LED Rocket switches, one rotary switch, two jumbo LED lamps and two PC edge connectors from desk top calculator plant! 79c EACH POWER SUPPLY A very fortunate purchase. One of the best industrial quality REGULATED supplies we have seen. High performance, small size. In- put is 1 20VAC. 60 HZ. Has the following regu- lated outputs: -5VDC at 800 MA: -15VDC at 1 25 AMP: - 25 VDC at 1 SOMA. $70.95 MINIATURE SPEAKER SPECIAL! 2 INCH — .8 OHM. PERFECT FOR CLOCKS! $.79 TO -5 HEATSINKS* Similar to Thermalloy 2205G Finned with insert. 5 for SI ROCKER SWITCH* HEAVY DUTY S.P.D.T. 3A. 125V.A.C. New, modern styling! 5 for$1 Z80 STARTER KIT SD System's Z80 Starter Kit enables the novice to build a complete microcomputer on a single board. Featuring the powerful Z80 microproces- sor the Z80 Starter Kit features: • Keyboard and Display • Audio Interface • PROM Programmer • Expansion and Wire Wrap Area • On Board RAM • 4 Channel Counter/Timer • Z-BUG Monitor in PROM • I/O Ports. This month's Special: $219.95 Kit $369.95 A&T SD SYSTEMS' STATE-OF- THE ART SBC- 100 KIT $219.00 10.99 Color Burst Crystal 3.57 MHz 89C TERMS: Add 30e postage, we pay balance. Orders under $15 add 75c handling. No COD. We accept Visa, MasterCharge, and Ameri- can Express cards. Tex. Res. add 5% Tax. Foreign orders (except Canada) add 20% P&H. 90 Day Money Back Guarantee on all items COMPUTER CORNER zso cpu;s Z80A 13.99 RELATED CHIPS 21 14 (300ns) 5.99 Z80 PIO 9.95 Z80 CTC 1 1 .95 2708 8.99 41 15 8/34.95 41 16 (200ns) 8/80.00 41 16 (150ns) 8/100.00 DISC CONTROLLER 1771 29.95 While in Dallas visit our retail store at Treehouse Shop- ping center. Garland Road and Jupiter. Circle 317 on inquiry card. BYTE September 1979 255 Fesdep Service To get information on the products advertised in BYTE, fill out the reader service card with your name and address. Then circle the appropriate numbers for the advertisers you select from the list. Add a 15-cent stamp to the card, then drop it in the mail. Not only do you gain information, but our advertisers are encouraged to use the marketplace provided by BYTE. This helps us bring you a bigger BYTE. Inquiry No. Page No. Inquiry No. Page No. Inquiry No. Page No. Inquiry No. Page No. 1 AB Computers 245 89 8 Administrative Systems 80 91 5 Advanced Access Group 110 96 4 Advanced Computer Products 252, 253 93 3 Aladdin Automation 77 94 6 Altos 21 97 16 American Square Computers 174 126 12 Anderson Jacobson 215 99 15 Apparat 234 B6 9 Apple Computer 25 102 10 AP Products 63 101 11 ASAP Computer Products 230 95 19 ATV Research 172 100 7 Automated Computer Software Serv 123 115 18 Automated .Simulations 212 120 21 Avlonlc Enterprise 172 125 13 Axiom 144 130 14 Basic Time 187 132 34 Beta (Div of Measurement 133 Systems & Controls) 154 134 31 Biotech Electronics 152 141 • Bits Inc. 191, 200 150 32 Buss/Charles Floto 172 159 • Byte Back Issues 213 160 36 BYTE Books 113, 114 161 ' Byte Subscriber 217 216 • Byte WATS 172 38 California Comp Systems 37 170 39 California Digital 235 169 41 Roy J Canon 174 175 43 CAP Electronics 52 176 45 Central Data 169 177 46 Centronics 73 178 47 Chrislin Industries 142 53 COMPCO 183 54 COMPCO 192 180 55 COMPCO 195 195 56 Compucolor Corp 39 200 • Computer Factory NY 155, 229 201 70 Computer Furniture & Accessories 161 202 • Computer Headware 215 203 75 Computerland 68, 141, 153 66 Computer Mart of NJ 93 207 68 Computer Service Center 217 206 72 Computer Tax Service 223 205 74 Computer Warehouse 217 208 73 Compulex 148 227 76 CT Micro Computer 60 215 77 CT Micro Computer 146 212 78 CT Micro Computer 147 213 79 CT Micro Computer 221 211 82 Contract Service Associates 211 214 83 Corvus Systems 47 277 84 Cover Craft 176 220 • Creative Software 223 221 80 Cromemco 1, 2 226 40 CTC 104 87 Cybernetic Micro Systems 177 210 85 Cybernetics Inc 224 211 88 Cygol 217 223 Data Access Corp 165 204 Data Discount Center 221 * Data/Print Publishing Co 168 Datasearch 222 218 Datasoulh Computer Corp 194 Data Terminals & Communications 185 198 Data-Trans 238 222 Diablo (Div of Xerox) 79 209 Digital Pathways 167 224 Disks Etc 213 225 Dontho Scientific 210 231 DRC (CA) 221 230 DRC (TX) 247 236 Electrolabs 228 237 Electronic Control Technology 213 255 Electronic Systems 236, 237, 238 256 Electronics Warehouse 244 257 Escon 83 258 Falcon Publishing 210 278 FMG Corp 32 279 Glmix 88 281 Godbout Electronics 173 289 H & E Computronics 197 280 Hamilton-Avnet 85 Hayden Book Co 138 282 Heath Company 17 283 Heath Company 105 284 Hobby World 226, 227 285 Industrial Micro Systems 139 286 Information Unlimited 150, 151 290 Integral Data Systems 49 291 Integrand 178 288 International Design Engineering 287 Assoc (IDEA) 217 293 Intersystems 157 Intertec Data Systems 135 295 Jade Co 248, 249 292 Jameco 232 Jameco 233 294 KML Marketing Inc 184 296 Kybe Corporation 69 298 Lifeboat Associates 90, 91, 149 299 Loweco Computer 217 297 Macrotronics 217 304 Marketllne Systems 171 305 Matrox Electronic System Ltd 44 306 Paul McCoy Enterprises Inc 220 Measurement Systems &. Controls 209 301 Micro Age 201 302 Micro Ap 205 308 Micro Applications Group 222 Micro Architect 212 309 Microcomputing Technology Inc 234 303 MicroDaSys 26 3t2 MicroDaSys 75 Micro Designs 170 374 Micro Diversions 5 315 Micro Focus 64 321 Micro Integration 128 311 MICROMAIL 219 323 Micro Mike's 224 310 Micropolis 108, 109 317 Micro Pro International 56, 57 318 Microsette 172 314 Microsoft 127 322 MicroSoftware (CAI) 210 334 Microsource 13 324 Microtek Inc 59 325 Mlcrotel Inc 147 316 Microware 164 331 The Micro Works 158 * Mikos 231 320 Mini Computer Suppliers 176 329 Mission Control 189 336 Morrow/Thinker Toys 31 330 Morrow/Thinker Toys 43 319 Mountain Hardware 143 Mountain Hardware 186 337 MVT Microcomputer Systems 45 328 National Technical Schools 210 " NEECO 94, 95 327 NEECO 159 332 Netronics 87 333 New England Recruiters 174 335 New World Books 134 340 Newman Computer Exchange 225 351 Northeast Computer Show 203 352 North Star Computers 27 353 NRI Schools/Electronics Div 193 354 Ohio Scientific Instrument CIV 357 OK Machine and Tool 220 359 Oliver Advanced Engineering 178 356 Omikron211 349 Omni Computer Corp 179 358 onComputing 97 355 Organic Software 174 350 Osborne & Associates 199 362 Owens Associates Inc 124 360 Pacific Exchanges 172 365 Pacific Office Systems 250 363 Page Digital 55 364 Page Digital 251 367 PAIA Electronics 221 368 PerCom Data CI 1 1 369 PerCom Data 111 PerCom Data 239 366 Personal Computing 79 180, 181 313 Personal Software Inc 51 379 Personal Software Inc 53 377 Pickles and Trout 177 378 Potomac Micro Magic 219 384 Power One Inc 89 387 Practical Applications 179 388 Priority I 241, 242, 243 389 Pro Comp/New England 250 391 Prog 80 163 393 P S Software House 172 394 Quality Software 224 401 Quest Electronics 240 RSI 33 RACET Computes 136 Radio Hut 255 Radio Shack 137 Radio Shack Auth Sales Center 171 RCA 103 RCA 132 RNB 146 RNB 160 S-100lnc218 S C Digital 204 St Jude 217 Sara-Tech Electronics 134 Frank Schiele 174 Scientific American 81 Seattle Computer Products 224 Michael Shrayer Software 145 Shugart Associates 6, 7 68 Micro Journal 175 Smoke Signal Broadcasting 122 Software Development and Training 156 Software Dynamics 212 Software Exchange 222 The Software Farm 174 . Solid State Music 61 Solid State Sales 231 ' SONTEX Inc 174 Southern Systems of Birmingham 140 SubLOGIC 83 Sunny International 246 SuperSoft 175 SuperSoft 212 SWTPC CM Sybex 125 Sybex 159 Synchro Sound 119 System Engineering Enterprise 131 Tano 133 Tarbell Electronics 11 Technical Software Inc 174 Technical Systems Consultants 117 Technology Transfer Inc 207 Thermax 217 3M Company 19 Robert Tinney Graphics 36 Tora Systems Inc 174 TransNet Corp 166 TRS-80 Software Exchange 162 US Robotics 72 Vector Electronic Co Inc 126 Vista Computer 254 V R Data 246 Wameco 245 Whitesmith's Ltd 222 Wintek Corp 172 Worldwide Electronics 172 X-Comp 92 X-Comp 170 Z s Systems 204 ECM6- GYTE's Ongoing Monitor Box 'Correspond directly with company. Article No. ARTICLE Page June BOMB 1 Ciarcia: Joystick Interfaces 2 Dahmke: Introduction to Multiprogramming 3 Teeters: Interface a Chessboard to Your KIM-1 4 Ellis: Some Musings on Hardware Design 5 Hallgren: A Low-Speed Analog-To-Digital Converter 6 Trimmer: Soldering Techniques 7 Powers: The Nature of Robots, Part 4 8 Harron: Inexpensive, Optical Paper-Tape Reader 9 Albus: A Model of the Brain for Robot Control, Part 4 10 Chrisp: Handy Pulser 11 Kasser:The Amsat-Golem-80 12 Barbier: Add Some Control to Your Computer 10 20 34 62 70 84 96 118 130 160 182 196 William D. Johnston again dazzled our readers with "Computer Generated Maps," Part II, page 100. Second place was taken by James Albus for con- tributing "A Model of the Brain for Robot Control," page 10. Placing a very close third and fourth, respectively, were G. A. Van den Bout, "Designing a Command Language and T. Radhakrishnan and M. V. Bhat, "Stacks in Microprocessors." 256 September 1979 © BYTE Publications Inc Low Cost Add-On Storage for Your TRS-80 In the Size You Want. When you're ready for add-on disk storage, we're ready for you. Ready with six mini-disk storage systems — 102K bytes to 591 K bytes of additional on-line storage for your TRS-80*. • Choose either 40-track TFD-100™ drives or 77-track TFD-200™ drives. • One-, two- and three-drive systems im- mediately available. • Systems include Percom PATCH PAK #1™, on disk, at no extra charge. PATCH PAK #1™ de-glitches and upgrades TRSDOS for 40- and 77-track operation. • TFD-100™ drives accommodate "flippy disks." Store 205K bytes per mini-disk. • Low prices. A single-drive TFD-100 TM costs just $399. Price includes PATCH PAK #1™ disk. • Enclosures are finished in system- compatible "Tandy-silver" enamel. Whether you need a single, 40- track TFD-1 00™ add-on or a three-drive add-on with 77-track TFD-200™s, you get more data storage for less money from Percom. Our TFD-100™ drive, for example, lets you store 102.4K bytes of data on one side of a disk — compared to 80K bytes on a TRS-80* mini-disk drive — and 1 02.4K bytes on the other side, too. Something you can't do with a TRS-80* drive. That's almost 205K bytes per mini-disk. And the TFD-200™ drives provide 197K bytes of on-line storage per drive — 1 97K, 394K and 591 K bytes for one-, two and three-drive systems. PATCH PAK #1™, our upgrade program for your TRSDOS*, not only extends TRSDOS* to accommodate 40- and 77-track drives, it enhances TRSDOS* in other ways as well. PATCH PAK #1™ is supplied with each drive system at no additional charge. The reason you get more for less from Percom is simple. Peripherals are not a sideline at Percom. Selling disk systems and other peripherals is our main business — the reason you get more engineering, more reliability and more back up support for less money. In the Product Development Queue . . . a printer interface for using your TRS-80* with any serial printer, and . . . thef/ecfr/c Crayon™ to map your computer memory onto your color TV screen — for games, animated shows, business displays, graphs, etc. Coming PDQ! PERCOM DATA COMPANY, INC. 211 N. KIRBY • GARLAND, TX. • 75042 ™ TFD-100, TFD-200. PATCH PAK and Electric Crayon are trademarks ot PERCOM DATA COMPANY. •TRS-80 and TRSDOS are trademarks ot Tandy Corporation and Radio Shack which have no relationship to PERCOM DATA COMPANY To order add-on mini-disk storage for your TRS-80*, or request additional literature, call Percom's toll-free number: 1-800-527-1592. For detailed Technical infor- mation call (214) 272-3421. Orders may be paid by check or money order, or charged to Visa or Master Charge credit accounts. Texas residents must add 5% sales tax. Percom 'peripherals for personal computing' Circle 304 on inquiry card. The Microcomputers you should take seriously. The Challenger III Series is Ihe microcomputer family with the hardware features, high level software and applica- tion programs that serious users in business and industry demand from a computer system, no matter what its size. Since its introduction in August, 1977, the Challenger III has become one of the most successful mircocomputer systems in small business, educational and in- dustrial development applications. Thousands of Challenger Ill's have been delivered and today hundreds of demonstrator units are set up at systems dealers around the country. Now the Challenger III systems offer features which make their performance comparable with today's most powerful mini-based systems. Some of these feafures are: Three processors today, more tomorrow. The Challenger III Series is the only computer system with the three most popular processors — the 6502A. 68B00 and Z-80, This allows you to take max- imum advantage of the Ohio Scientific software library and the tremendous number of programs offered by independ- ent suppliers and publishers. And all Challenger Ill's have provisions for the next generation of 16 bit micros via their 16 bit data BUS, 20 address bits, and unused processor select codes. This means you'll be able to plug a CPU ex- pander card with two or more 16 bit micros right in to your existing Challenger III computer. Systems Software for three processors. Five DOS options including develop- ment, end user, and virtual data file single user systems, real time, time share, and networkable multi-user systems. The three most popular computer languages including three types of BASIC plus FORTRAN and COBOL with more C3-B Circle 290 on inquiry card. languages on the way. And. of course, complete assembler, editor, debugger and run time packages for each of the system's microprocessors. Applications Software for Small Business Users. Ready made factory supported small business software including Accounts Receivable, Payables, Cash Receipts, Disbursements, General Ledger, Balance Sheet, P & L Statements, Payroll. Per- sonnel files. Inventory and Order Entry as stand alone packages or integrated systems, A complete word processor system with full editing and output for- matting including justification, propor- tional spacing and hyphenation that can compete directly with dedicated word processor systems. There are specialized applications packages for specific businesses, plus the vast general library of standard BASIC. FORTRAN and COBOL software OS-DMS, the new software star. Ohio Scientific has developed a remarkable new Information Manage- ment system which provides end user The Challenger 111 Series from Ohio Scientific. C3-S1 intelligence far beyond what you would expect from even the most powerful mini- systems. Basically, it allows end users to store any collection of information under a Data Base Manager and then instantly obtain information, lists, reports, statistical analysis and even answers to conventional "English" questions perti- nent to information in the Data Base. OS-DMS allows many applications to be computerized without any programming! The new "GT" option heralds the new era of sub-microsecond microcomputers. Ohio Scientific now offers the 6502C microprocessor with 150 nanosecond main memory as the GT option on all Challenger III Series products. This system performs a memory to register ADD in 600 nanoseconds and a JUMP (65K byte range) in 900 nanoseconds. The system performs an average of 1 5 million instructions per second executing typical end user applications software (and that's a mix of 8. 16 and 24 bit nstructionsl). Mini-system Expansion Ability. Challenger III systems offer the greatest expansion capability in the microcomputer industry, including a full line of over 40 expansion accessories. The maximum configuration is 768K bytes RAM, four 80 million byte Win- chester hard disks. 16 communications ports, real time clock, line printer, word processing printer and numerous control interfaces. Prices you have to take seriously. The Challenger III systems have phenomenal performance-to-cost ratios The C3-S1 with 32K static RAM, dual 8" floppies, RS-232 port. BASIC and DOS has a suggested retail price of under $3600. 80 megabyte disk based systems start at under $12,000, Our OS-CP/M soft- ware package with BASIC, FORTRAN and COBOL is only $600. The OS-DMS nucleus package has a suggested retail price of only $300, and other options are comparably priced. To get the full story on the Challenger III systems and what they can do for you, contact your local Ohio Scientific dealer or call the factory at (216) 562-3101 . C3-B wins Award ol Merit al WESCON 78 as the outstanding microcomputer application lor Small Business C3-OEM