Introducing . ..the world's lowest cost
computer system TM
JOLT@) is the new, fully-tested microcomputer with the exclusive on-board DEMON@) debug monitor. You can build it, plug it in and talk to it in three h.ours or less .. . for a price of just $249! The basic JOLT@) card includes an 8-bit MOS Technology Model 6502 CPU, which requires no clock, can directly address 65k of memory, has two index registers , 58 instructions with 11 addressing modes , two interrupts and includes both single step and address halt capability. And that's only a part of it. JOL T' s@l CPU card is avail able I MMEDIATEL Y* in either kit form or as sembled ($249 fo r the kit in single quantity and $348 assembled). Either way, the JOLT @l CPU is completely teste d prior to delivery . It comes complete with a termi nal in terface (TTY or EIA) and a unique software DEbugger/MONitor called DEMON@l, for which fu ll documentation is provided. It is ve ry easy to program, and All kits are de livered with a complete instruction manual and packaged for easy visual identifica any JOLT @l delivery inc lu des an easy-to tion of parts to aid you in assembly. fo llow assembly instruction manual, show to any termin al speed from 10-30 CPS. And the quantity of one price is what you in g you exactl y how to pu t everything With it, you can display and alter you r CPU mi g ht expect to pay in quanti ties of together . .. correctly. Complete assem register and memory locations, plus you 100 ... ve ry inexpensive I bly should take you no more th an Ihree can read , write and punch Hex formatted There 's also a JOLT@) I/O card for you, hours if you choose the CPU in kit form. data ... wi th Write/Punch BNPF format Besides the JOLT @l CPU - th e 6502 from data for PROM programmers. It has un li our Peripheral Interface Adapter. You MOS Technology - the basic JOL T@l mited breakpoinl capability along with can't beat the price - single kit 96 card has a fully static memory accom separale non-maskable interrupt entry bucks - or the function. modating 512 bytes of the user RAM . The and id entif ication. External device inter JOLT @l CPU memory also has 64 bytes of rupts can be directed to any location you inlerru p t ve ctor RAM. ROM Program choose, or tlley can be defaulted to memory on the basic card consists of 1k DEMON@l recognition. DEMON@l also bytes of monitor/debugger with an au gives you (1) a completely protected ROM tomatic Po w er-On bootstr ap program resident debug/monitor; (2) the capability - so you can start ta lking to JOLT @l and it to begin execution at any location in mem to you as soon as you plu g it in to your ory; (3) th e capability to bypass DEMON@l terminal. On-board Input/Output devices entirely to permit full control by you over on the JOLT @l CPU ca rd inc lude TTY 20 your system; (4) a high-speed 8-bit parallel mi lliamp current loop and an EI A inter input option ; and (5) it includes user call a Pictured above is the assembled JOL T'fB! CPU face, both fu ll duplex. The card has hig h ble DEMON@l I/O subroutines. MOST IM card with DEMON@!. just plug it in and you 're ready to go. speed reade r interface lines and 16 fully PORTANT, DEMON@l IS INCLUDED AS programmable user I/O lin es with full TTL STANDARD WITH ANY JOLT@l CPU KIT Tile JOLT@l PIA (Periphe ral Interface drive. OR ASSEMBLED BOARD! Adapter) I/O card includes two PI A LSI Nobody, but nobody, except MAl can chips, 32 in put/output lines, two interrupt Obvious ly, the JOLT@) basiC card is a lines , on-board decoding and standard offer you an on-board debugger/monitor computer in and of itself. But you can add TTL drive. It is also fu lly programmable like DEMON @) . It's fully documented, significantly to its capacity and versatil and available IM MED IATE LY' in either kit too . ity by adding 4k RAM JOLT@) memories or assembled form ... at a very attractive The exclusive DEMON@l Debug Moni tor - in one card or a whole bunch. A RAM single un it price ($ 140 assembled). really makes JOLT @l one of the most out card kit is only $265 (S 320 assembled). Considering the function and capacity of standing computer sys tems offered at any the JOLT@) Power Supply Card, you time, at any price. Even without DEMON@l Now. 4096 Bit RAM 4K BYTE and its superior software featu res, JOLT @l Th e JOLT @l memory card is a fu lly static probably th ink the quantity of one price is the lowest cost computer system in ex is 4,096-bit Random Access Memory (RAM) - $145 - is a misprint. It isn't. tence. And DEMON@l is a bonus you'll with 1 microsecond access time and on The JOLT @l fam il y also in c ludes a power have to use to believe. First, it se lf-adapts board decoding. It is also available now.' supply card, which operates at any of three vo ltages - +5, + 12 and - 10. The Th e JOLT @J Universal card is completely •••••••••••••••••••••• •• • power supply supports the basic JOLT@J nude. It' s a bl ank you can use any way • CPU card, plus 4,096 bytes of RAM and you wish, for control panels, T.V. inter • 1/0. The only two words for the price are faces, keyboards, LEO 's, or any other in • THE JOLT PLAIN ENGLISH WARRANTY " di rt cheap. " It is available for delivery • terface logic, because the card's holes • All componenls in the JOLT@> family are immediately with a single unit kit price of • are drill ed to accept 14, 16,24, or 40 pin • new and ful ly tested prior to shipmen t. Kit $145 ($190 assembled). sockets and has the same form factor as • components are fully warranted during the the other JOL T@J cards. Th e single unit • first 60 days of owne rsh ip . Assembled price is just $25. • parts are fully warranted during the fi rst 6 • months of ownership. If you r properly as If you think you need extra cables, wires • sembled kit does not work. just ship you r • order back to Microcomputer Associates and the like, choose a Super Value • Inc . and we'll rep air. replace . or refund JOLT@) Accessory Bag. A $55 Value for • you r money. • just $40 . • • • • Th e JOLT @J Accessory Bag in cludes 25 ••••••••••••••••••••••••• separate parts , enough hardware to con nect one JOL T@J card to another. Order an 20% BONUS The assembled power supply card shown above powers the JOLT@! CPU, I/O, and RAM Accessory Bag for each additi onal JOL T@J NOW! Special ONE TIME BONUS DISCOUNT. Memory cards. card. Th e Bag contains such necessary Order one CPU before November 10,1975 and You can also choose a blank JOLT@) uni items as flat cable, connectors , cord deduct 20% off of all additional cards and ac spacers, hardware, wire , etc. cessories. (Note: Discount does not apply to versal card. Or several. CPU cards, assembled or unassembled.)
We told you JOLT@) was the world's lowest priced computer system. These prices prove it.
JOLT KITS JOll'@' ASSEMBLED PRICES (All PAYMENTS MUST BE IN U.S . DOllARS) (All PAYMENTS MUST BE IN U.S. DOllARS) QUANTITY PRICING QUANTITY PRICING 1-4 5-19 20-49 50-99 100 u~ 1-4 5-19 20-49 50-99 100 uQ JOLT@> CPU $249 $235 $230 $225 $215 JOLT@> CPU $348 $325 $320 $3 15 $305 JOLT@> RAM 265 255 250 245 235 JOLT@> RAM 320 305 300 295 280 JOLT@> I/O 96 90 88 82 75 JOLT@> 110 140 125 120 11 5 105 JOLT@> POWER JOLT@> POWER SU PPLY 145 135 130 128 115 SUPPLY 190 175 170 165 150 JOLT@> UNIVER SAL CARD 25 20 18 16 14 THE NEW JOll'@' FROM MAilS AVAilABLE ONLY ON A DIRECT BASIS. JOLT@> ACC ES SORY USE THIS COUPON TODAY TO ORDER FROM __ BAG 40 36 34 32 30 All JOLT@> KITS ARE DELIVERED COMPLETE WITH A DETAilED ~;\'~~fom,!;~'6',~:,:~~c:.'~ loe. AND ILLUSTRATED ASSEMBLY MANUAL &\ Los Altos, Calif. 94022 I ( Phon e (415) 941-1977 \ r ' Order will be shipped within 15 days. ©1975 Pehaco Corporation , This coupon wi" bring you a JOLT@) ! Complete and return it. I Here is my check, money order or credit card payment for the NOW! Special ONE TIME BONUS DISCOUNT. I following JOll'@' products. If a U.S. or Canadian order, please add 200/0 Order one CPU before November 10, 1975 and 20% $4.86 for shipping, handling and insurance. (Orders to all other BONUS deduct 20% off of all additional cards and ac- BONUS I countries are priced F.O.B. los Alios and will be shipped FREIGHT cessories. (Note: Discount does not apply to COllECT.) CPU cards, assembled or unassembled.) I Send me immediately: PLEASE CHARGE THE TOTA L TO MY CREDIT CARD QUANTITY PRODUCT PRICE BANKAMERICARD # ------I JOLT@> CP U KIT $ _ _ _ _ MASTER CHARGE # JOLT@>RAM MEMORY KIT (include 4-digit #) JOLT@> I/O KIT My cred it card exp ires on JOLT@> POWE R SU PPLY KIT SIGNATURE I JOLT@> UNIVERSAL CARD Al l credit ca rd orders must be signed l ) ___ JOLT@> ACC ESSORY BAG I UNDERSTAND THAT ALL U.S . ORDERS WILL BE SHIPPED VIA U.P.S. AND ALL I ___ JOLT@> CPU ASSEMBLED tNTERNATIONAL ORDERS WILL BE SHIPPED BY AIR. SEND MY ORDER TO: ___ JOLT@> RAM MEMORY ASS EMBLED I ___ JOLT@> I/O ASS EMBLED NAME --- JOLT@> POWER ~~:ALLY ASSEMB LED $ ADDRES S I ORGANIZA TlON ...:.+..:::U"".S""/ ..:::C:..::ANc.:.:A"",D:::A-,--",SHc..::I"--P,-,PIc..:N""G::..:,/H.:cA.:cN.:..::D:..=L,,,-IN.:..::G=:./"-.1N"'S""U""RA:..::N'-'-C=.:E::...... ____ 4.86 NOTE: CA LIFORNI A RESIDENTS , +6% SALES TAX CITY ------STATE ----- ZI P ---- TOTAL REMITTANCE (U.S. DOLLARS ONLY) $ ---- PHONE --~~;::-;--==-r::::;::;-- I (Include Area Code) !IlJI/ MAIL Pehaco Corporation, JOLT@> Sales Agentsd ' Make your check payable to: Microcomputer Associates Inc. I ~rJ, YOUR Microcomputer Associates Inc. Dept. G (ll. j International Orders: Payment should be cabled to Account I ORDER 111 Main St., Los Altos, Ca 94022 ~ #00417-06355 Ban k of America, 215 So. Murphy LTD All 0"", "bj'" 10 1h ' p'i",4a.p.p.r.ov.a.lrofJt.h.e.m.8.n.urfa,4ct.u.re.r••. •••• J.A.ve.n.u.e., rsu,4n.n.yv.a.le.,.caIif.o.rn.ia. '.U.S,Aj' .94 .0.8.6. r J J SOFTWARE - ••••••• is the best thing to feed your computer! Makes it healthy! Gets rid of that dull, aimless, blinking lights expression so many small systems exhibit these days. Feed your machine SOFTWARE! Make it feel good. Machine will then perform services. That will make YOU feel good. Put your machine on a good SOFTWARE diet like some of the following CHOW! ASSEMBLER PROGRAMS FOR THE '8008' Discusses a "minimum length" Assembler program that can reside in 2K of memory, plus a more sophisticated version for those who have additional memory and desire a more powerful version. Included in this manual is a thorough explanation of the fundamental concepts of an assembler's operation, details on how to format the "source listing," step-by-step analysis and presentation of subroutines, program flow charts, and assembled listings of the programs ! Price? A very reasonable $17.95. AN '8008' EDITOR PROGRAM Describes variations of an "Editor" program that can reside in 2K of memory. Additional memory may be used to increase the size of the text buffer. The program enables one to manipulate "text" in order to create "source listings" or perform other kinds of text preparation. Includes discussion of routines, flow charts, and assembled listing. Priced at just $14.95. '8008' MONITOR ROUTINES Describes a "Monitor Control" package that allows you to contro l the operation of your computer from an external "keyboard" device. Various routines enable you to examine and modify memory locations and CPU registers, set "breakpoints" and execute programs for "debugging" purposes, control bulk storage I/O devices, and perform other useful functions. This manual comes complete with subroutine explanations, flow charts, and an assembled, highly commented program listing. Low priced at just $11 .95. NEW! - FOR HUNGRY 8080 MACHINES! AN ~8 0 80' ASSEMBLER PROG RAM This assembler program utilizes some of the unique routines we utilized in our popular '8008' assembler which enables us to provide an '8080' assembler that operates comfortably in 4K bytes of RAM (including the symbol table). An unusual feature of this assembler program is that it has been designed to accept mnemonics closely re lated to those used by SCELBI for our'8008' based machines. What this means is that programs originally written for an '8008' unit can be directly processed by this assembler to produce object code for an '8080' machine! NEAT! Of course, it also handles the extended instruction set of the '8080' as we ll. This program is provided in our popular style of a manual that discusses the major routines, presents pertinent flow charts, and includes a highly commented assembled listing. $17.95. AN '8080' EDITOR PROGRAM This is essentially a "carbon copy" of the material in our earl ier manual describing a '8008' Editor, except the assembled listing is provided with the machine code for an '8080: It is a good deal at $14.95. '8080' MONITOR ROUTINES These routines perform the same types of functions as described above for the '8008' version except routines were specifically developed to utilize the extended capabi li ties of the '8080' instruction set. Great price at just $11.95. WANT TO IISPOON FEED" YOUR MACHINE? You CAN learn how to develop your own machine language programs. And, if you are really serious about utilizing a small system effectively, you had better plan on learning something about it sooner or later! Here is a good way to get started. MACHINE LANGUAGE PROGRAMMING FOR THE '8008' (AND SIMILAR MICROCOMPUTERS) THIS manual was written to provide the reader with the detailed knowledge one needs to know in order to successfully develop machine language programs. This information packed publication discusses and provides numerous examples of algorithms and routines that can be immediately applied to practical problems. Virtually all the techniques and routines illustrated in the manual can also be applied to other similar microcomputers such as "8080" systems (by applicable machine code conversion). The price of this exciting new manual is a low $19.95. (The floating-point arithmetic package presented in the publication is worth that price alone!) Prices given are for domestic delivery at book mailing rate. Add $2.50 for each publication if PRIORITY air service desired (U.S.) Overseas - include $6.00 for each publication for airmail service. (Pricing, specifications, availability subject to change without notice_) Order direct from: 1322 REAR BOSTON POST ROAD Il:llll3l 1:0Mll'IJIIII DEPT OJ MILFORD CONNECTICUT 06460 1:0~llJlII~(i I~I:. In I:he Queue #5 JANUARY 1976 Foreground
LET THERE BE LIGHT PENS ...... _ .. _ ...... 26 Hardware - Loomis LI FE Line 4 _ . . _ ...... __ . ... _ .. _ ...... _ .32 Applications - Helmers GOLF HANDiCAPPiNG ...... " ...... 46 Applications - Haller PHOTOGRAPHIC NOTES ON WIRE WRAPPING ...... 56 p.12 Techniques - Helmers .;1' ',I i ", ,I !.' 11,'1',;i 11" '''"I''II ,"II "111 "l11...,· Background I II'" ",,,,,,,11', !IIII "Ii ,I I ' . '" " .. " II,,', NEW MINI-MICROCOMPUTER SYSTEM ..... __ . . _... . _12 "" 'j""1 ; 'II ' II' I~' Ilt'li 'I Ii' Processors - Baker " HORROR STORY ...... " , _ ...... _ . .. .. 31 FREE-HAND WRITING Problems - Warren TOTAL KITCHEN INFORMATION SYSTEM ...... 42 p.26 Systems - Lau INTEL 8080 OP CODE TAB LE . .. . __ ,. _ ...... 50 Reference - Dittrich MORE TO BLINKING LIGHTS THAN MEETS THE EYE . . 52 Applications - Helmers TAKING ADVANTAGE OF MEMORY ADDRESS SPACE .. 60 System Design - Luscher KO R k? ...... 64 Style - Peshka p . 32 THE CT-1024 KIT ...... 92 Review - Hogenson
Nucleus
In This BYTE ...... _ .4 Beach Ball Software ...... , ...... _ .....9 BOMB ...... 10 For the Joules, It's a Steal ...... 67 Clubs, Newsletters ...... 68 p- 56 MITS Computer Caravan ...... 73 E That Didn't Take Long at All ...... _ .. . . 74 8K --, Classified Ads ...... _ ...... 74 I BYTE magazine is published , 1110ntl1ly by Green Publishing, BYTE's Bugs ...... 77 I If Inc., 70 Main St, Peter , Answers to December Word Hunt _ ...... 77 I borough , New Halnpshire I 03458. Subscription rates aI-e 4K $ 1 2 for o ne year worldwide. Sphere Rolls Into Town ...... __ 80 Two years, $22. Three years, Letters .... _...... _...... 82 $ 30. Second c lass postage II application pending at Peter Book Reviews ...... 88 borough, New Hampshire 03458 and at additional mail The BYTE Questionnaire ...... _ . ...96 p . 60 ing offices. Phone 603-924-72 17. Entire conten ts Reader's Service ...... 96 cop yright 1975 by Gree n Pub lishing, Inc, Peterborough NH 03458. Address e ditorial co rrespondence to Editor, BYTE, 70 Main St, Peter borough NH 03458. New BYTE phone: 603-924-7217 In This ~~TI
On the cover, artist Robert Tinney has provided a scene In the October BYTE , Ri chard Gar dner commented on the depicting the combination of computers and golf handicapping app li cation of personal computers in hou sehold situations. In described by Dr. George Haller in hi s articl e. this issue, Ted Lau continues on th at theme with an article of "structured specul ation" on the Total Kitchen Information How would you like a PDP-ll/40 in your base ment System (TKIS). computer room? The price would probably be too high fo r the typical amateur. But Digital Equipment Corporation also Computers solve problems, right? On e prob lem which makes the LSI-ll, a microcomputer which implements the go lfers have is calculating handicaps so that duffers can pl ay PDP-ll/40 instruction set and inh erits a wealth of ex isting aga i nst pros in th e same tou rn ament. In Golf Handicapping PDP-ll software. Turn to Bob Baker's article on the LSI-ll (or: Buy a New Peripheral with Money Earned from Your for a summary. Local Duffers), Dr. George Ha ll er desc ribes a progra m he concocted to serve as the bas is for a part time bu si ness How do you draw a picture on an osci ll oscope displ ay? Add calcul ati ng golf handicaps at hi s country club. For readers with a Light Pen as described by Sumner Loomis, and you wil l be teenage children, this mi ght make a great opportunity fo r the able to add and delete points of li ght. kids to make som e money to help pay for college expenses while learning how to run a bu siness. When the LI FE program can't figure out a key code, it calls DEFAULT, as described in LIFE Lin e 3. This is sue's LIFE Computer systems have many resources which can be used Line 4 specifies the DEFAULT routine used to enter cursor by the person who assembles or modifies the design . One motion control data and numeric data for th e KEY resource which is very important is the memory address space BOARD INTERPRETER. As a combined hardware and inh erent in the design of the computer. Taking Advantage of software system, the LIFE application enters th e realm of Memory Address Spaces by James Lu scher can provide hardware for the first time with a simple circuit to interface important improvements in speed and function of your the cursor motion control keyboard and an ASCII keyboard sys tem. via the same input port. Wh at is sty le? In his articl e K or k?, Manfred Peshka Wire wrapping is a technique often used to asse mbl e describes some notational conventions which apply to BYTE's circuits. Turn to Photographic Notes on Wire Wrapping for unique combination of hardware and software informati on. some pointers for your own custom computer interfaces . Whil e the change of these standards is incomplete in this iss ue, future BYTEs will empl oy the stand ard abbrev iati ons and According to tradition, no computer is eve r complete units throughout. without blinking lights. But There's More to Blinking Lights Than Meets the Eye, or the control panel designer's utilitari an Wh at is one of the most useful peripherals? Why , the motives. This issue provides a few ide as for using simpl e and television set of course. To us e the TV you need an interface. inexpensive LED indicators in ways far removed from the One such interface is the CT-l024 product by SWTPC traditional control panel application. revi ewed by Jim Hogenson.
4 Lowest Price in the World!
In January of 1975, MITS stunned the computer world with Altair 680 Documentation the announcement of the Altair 8800 Computer that sells for The Altair 680 kit comes with complete documentation $439 in kit form. including assembly manual, assembly hints manual, operation Today MITS is announcing the Altair 680. manual, and theory manual. Assembled units come with The Altair 680, built around the revolutionary new 6800 operation and theory manuals. Turnkey model and CPU boards microprocessor chip, is the lowest priced complete computer on also include documentation. the market. It is now being offered at the special, NOTE: A complete set of Altair 680 manuals in low price of $345! a 3-ring Altair binder is now available for $14.50 (regularly $25). Offer expires January 30,1976. The Altair 680 comes with power Delivery supply, front panel control board, and CPU board inclosed in an Personal checks take 2-3 weeks to 11" wide x 11" deep x411/ l6" case. process while money In addition to the 6800 processor, orders and credit card the CPU board contains the follOwing: purchases can be 1. 1024 words of memory (RAM processed in 1-3 days. 2102 type 1024 x I-bit chips). Delivery should be 2. Built·in Interface that can 30-60 days but this be configured for can vary according to RS232 or 20 rnA order backlog. All Teletype loop orders are handled or 60 rnA on a first come, first Teletype. served basis. 3. Provisions for 1024 words of Altair 680 Prices ROM or PROM. The Altair 680 can be Altair 680 complete computer kit_ . __ .... __ $345 Altair 680 assembled and tested. _. . _ . __ . _...... ____ . $420 programmed from the front Altair 680T turnkey model (complete Altair 680 except panel switches or it can be front panel control board) Kit Only ____ .. _. _. . ____ . .. $280 connected to a computer terminal (RS232) or a Teletype such as Altair 680 CPU board (including pc board, 6800 micro processor chip, 1024 word memory, 3 way interface an ASR-33 or surplus five-level Baudott Teletype (under $100). and all remaining components except power supply) . _$195 The Altair 680 can be utilized for many home, commercial or Altair 680 CPU board assembled and tested ...... $275 industrial applications or it can be used as a development system Option IC socket kit (contains 40 IC sockets. CPU, memory and PROM sockets come with 680 kit) ...... $ 29 for Altair 680 CPU boards. With a cycle time of 4 microseconds, Option cooling fan (required when expanding 680 l6-bit addressing, and the capability of directly addressing internally) ...... _ .. _ . _. .. _...... $ 22 65,000 words of memory and a virtually unlimited number of Option cooling fan installed ...... $ 26 I/O devices, the Altair 680 is a very versatile computer! PROM kit (256 x 8-bit ultraviolet, erasable 1702 devices) $ 25 Connectors (Two sets of 25-pin connectors. Required Altair 680 Software when interfacing 680 to external devices) . . _ ...... $ 22 Software for the Altair 680 includes a monitor on PROM, Prices. de livery and specifications subject to change. assembler, debug, and editor. This software will be available to Altair 680 owners at a nominal cost. Future software development will be influenced by customer demand. MITS will sponsor lucrative software contests to encourage the rapid growth of the Altair 680 "Creative Electronics" software library. Programs in this library will be made available to all Altair 680 owners at the cost of MITS/6328 Linn N.E_, Albuquerque, NM 87108 505/ 262-1951 t. . printing and mailing. MAIL THIS COUPON TODAY! Altair Users Group o Enclose9ischeck forC$----'''---,,;~----,~_+-f!, o BankAmericard # ____ _ All Altair 680 purchasers will receive a free one year o Altair 680 0 Kit qAssembled",D Altair 688T 0 Altai~?80CPU membership to the Altair Users Group. This group is the largest o Socket Kit 0 Fan 0 PROM kiteD Documentation Special of its kind in the world and includes thousands of Altair 8800and o Please send Iitgrature 680 users. NAM~E ______------~------~------Members of the Altair Users Group are kept abreast of Altair I ADDRESS'~ ____~~ ____~ __~ -=T-____ ~ __ ___ developments through the monthly publication, Computer CITY STATE & ZIP...... ,.,... _ _ Notes. MITS/6328 Linn N.E/i"Albuquer;que,NM 8Z~.08 505/2~2.1951 ; CALL FOR PAPERS-ACM '76 OCTOBER 20-22,1976... HOUSTON Our 1976 Annual Conference will be held October You are invited to submit a paper on any aspect of 20 - 22 in Houston. We feel that it will be one of computer research, development, or implementation. the most relevant ACM conferences ever held, both High quality papers of a theoretical, state-of-the'art or for the practicing professional and the researcher. The tutorial nature are welcome. The technical program for conference facilities in downtown Houston's Regency ACM '76 will again be organized around the ACM Hyatt House will be outstanding. You will find that Special Interest Groups, although additional sessions ACM '76 will be a place where you can enjoy your· will be provided for papers of general interest or those self, renew old acquaintances, make some new ones, not related to any SIG. and participate in a serious technical discussion of the problems and potential of our industry. Plan to attend. Papers must not have been previously presented or published; they should not exceed 10 published pages, Olin Johnson including a 100·word abstract, bibliography, and illus General Chairman, ACM '76 trations; and they must be received in four copies by March 1, 1976. All papers will be refereed either by the SIG's or by reviewers selected by the Technical Pro gram Committee. Notification of acceptance will be made by May 1. If you intend to submit a paper, and we sincerely hope that you do, please send in the coupon below. If you have an idea for a good session or some other technical program idea, please do the same or start promoting your idea in your SIG but do it now! Be a part of the spirit of ACM '76!
about the conference about the technical program
II ACMII Be a part of the "Spirit of ACM '76"
ASSOCIATION for COMPUTING MACHINERY 1976 ANNUAL CONFERENCE Roger W. Elliott Technical Program Chairman, ACM '76 Department of Industrial Engineering Texas A & M University College Station, Texas 77843 1713) 845·5531 Name ______Phon e ______Address ______
Ci ty State ______Zip ______o I intend to submit a technical paper. Tentative title ______SI G (optional) ______o I am enclosing a technical program suggestion. o Please call me. I would like to discuss an idea for the technical program.
6 ...... 11~11~11~1I0Riii~S AR~ II~IIAD~ Of JI~I~SE :::
INTEGIATED CIRCUITS 8K BY 8 BOARD", $352 (ADD $48 & WE PROGRAM)
2102 lK STATIC RAM---STILL ONLY $1,95 4K BY 8 BOARD, , ,$200 (ADD $25 & WE PROGRAM) ONE-TH I RD OF A CENT PER BIT--- Our most popu GUARANTEED FASTER THAN 750 NS, Buy l a r memory kit. You get sockets for a ll IC s, 2K BY 8 BOARD", $125 (ADD $15 & WE PROGRAM) industrial-qual ity plated-through board, lots 100, TAKE 20%; BUY 1000, TAKE 30%, of bypassing,S voltage regulators to sha re Now you can stuff up to BK of your favorite soft the power l oad (less thermal problems, more 5203 2K EROM --- $9,50, THIS STATIC ware----edi tor/assembler or what have you----on a re l iability), typical 500 ns access time at MEMORY I S FULLY PROGRAMMABLE AND MAY board. Program it yourself or have us do the pro 25°C, and buffered add r esses and outputs (no BE ERASED WITH UV LI GHT , NON-VOLATILE, gramming . Just I ike the RAM kit, DIRECT ALTAIR input presents more than 1 LPTTL l oad; out 8800 PLUG-IN COMPATIBLE. Includes sockets, bypas puts can drive 20 standarG TTL l oads). May sing, industrial-quality plated- through board, be powered with 8 volts unregulated; or by 11\5204 4K EROM---$24,50 , SIMILAR TO buffered addresses and outputs, on board regula bypassing the on board regula tors, with THE 5203, BUT 4K OF MEMORY, tion. LOW POWER: Full 8K requires tA @ 5V , ISO +5V . Complete with assembly instructi ons rna @ -12V. Fi I e protect feat ure includes 1 ine re and l ogic print of the RAM board. ,1 MEMORY/PROCESSOR 8 BIT CHIP SET: ceiver with real hysteres i s to prevent false trig $32 ,50 BR I NGS YOU 8 OF OUR 2102s ger i ng on noise. EXPANDABLE: If you buy our 2K ALTAI R 8800 OWNERS, PLEASE NO TE , AND AN 8008 MI CROPROCESSOR, board and war:t to move on to bigger and better THIS MEMORY BOARD KI T, LIKE OUR th i n95 ( 1 ike 8KJ. a 11 yo u add is more sockets and OTHER MEMORY KITS, ISO I RECTL Y EROMS' , Your board doesn1t become obso l e te. PLU,G-IN COMPATIBLE WITH THE 8800. ~ We've got 4K by 8 boards pre-programmed with 8080 assembler, editor, and monitor rou ImI tines . $200 buys you the same quality and ALTAIR PLUG-IN COMPATIBILITY as our other Efl()m E()flfl[) memory kits . Another advantage: because this is EROM rather than mask programming, you can make changes if desired. Speaking of changes, alth ough these routines work our really well, we are including 2 free updates to purchasers should bugs or modifi- SfEtlflL ()ffEfl cations develop. Any additional changes are available for a very nominal charge. SEND $2 . 95 (PPD) FOR OUR SOF TWARE INFO PACKET I F YOU WANT MORE INFO OR WANT TO LOAD YOUR OWN ROM BOARD. INCLUDES INSTRUCTION LISTING SCHEMAT I~ ASSEMB L Y DATA, ETC. J~ lOW TINY ~ 0~OPROC"Ot.Sa Aolal~Y 1>0WI12 ~ ~O' S\vitcll SINGLE POLE, SEVEN POSITION + OFF. IN TO- 5 CAN; T I NY FOR kHOII~W CIRCUIT BOARD MOUNTING. GOOD FOR PROGRAMMING & MUCH MORE. $1.25 EA OR 3/$2.95 COMPARED TO STANDARD TTL, LOW POWER SCHOT TKY OFFERS 1/5 THE PO WE R CONSUMPT ION-BU T WITH NO §@[t:!] @[? & SPEED PENALTY . CONSIDERED BY MANY AS THE LO GICAL SUCCESSOR TO STANDARD TTL . ©[}={]§&~ 74LSOO Quad 2 input NAND gate .40 74LS04 Hex inverter .45 A POWERFUL 16 BIT PROCESSOR. 40 PIN DIP; CAPAB ILITY FOR 45 74LS08 Quad 2 input AND gate .40 CLASSES OF INSTRU CT I ONS AND UP TO 337 INSTRUC TIONS. INTERFACE ©[b@©~ 74 LS I 0 Triple 3 in NAND gate .40 CHIPS PROVIDE TTL COM PA TIBILITY- - RAMS AND ROMS PRO V IDE MEMORY, 74LS20 Dua I 4 input NAND gate .40 AND THE PACE DA TA PACKET TELLS YOU HOW TO APPLY EVERYTHING . @D~c~@ 74LS42 BCD to decima l decode 1. 25 74 LSI38 I of 8 decoder 1. 40 TH I SIS THE SUCCESSOR TO OUR PACE DATA PACKET AVAILABLE SEPARATELY FOR $2.50 (COVERS PRINT 74 LSI 68 Dec Syn Up/Down cntr 1. 50 'CHEAP CL OCK ' KIT. IT IS AN ING AND POSTAGE). 80 PAGES OF INFORMATION ON THE CHIP ITSELF, 74LSI69 Bin Syn Up/Down cntr 1. 50 EASY TO ASSEMBLE KIT THAT IN SOFTWARE, SYSTEM ORGANIZATION, AND MORE. ALSO INCLUDES AN 11" 74LSI75 Quad l atch 1. 38 CLUDE S EVER YT HING YOU NEED TO BY 17" INCH FOLDOUT LOGIC PRINT OF PACE IMPLEMENTATION. MAKE A WORK I NG CLOCK, EXCEPT CAS E AND HARDWARE. IF YOUR INTERE ST IS MICROCOMPUTERS, AND PARTICULARLY PACE, YOU WILL WELCOME THIS DA TA PACKET. PURCHASE PRICE REFUNDABLE WITH IT FEATURES 3/10 I N. READOUT5 FOR HOUR S, MINUTES, AND SEC ONDS . 50/60 Hz OPERATION, 12 H~_dfo DR 24 HOUR DISPLAY FORMAT. PACE ORDER' ®.®@)@®OO~ SOCKETS FOR IC AND READOUTS PROVIDED . THE READOUTS CAN BE EAS I L Y lin
TITLE: Microcomputer Dictionary & Guide AUTHOR: Charles J. SippI This new microcomputer dictionary fills the urgent need for all computer people, engineers, scientists, industrialists, communications people - as professionals, amateurs, teachers, or students - to become quickly acquainted with the terminology and nomenclature of a new revolution in computer control capa bilities in areas that pervade most of man's daily activities. Over 3500 definitions and explanations of terms and concepts (approx. 350 pages) relating to microprocessors, microcomputers and microcontrollers. There are also separate appendices on: programmable calculators; math and statistics definitions; flowchart symbols and techniques; binary number systems and switching theory; symbol charts and tables; summaries of BASIC FORTRAN and APL. In addition there is a comprehensive electronics/computer abbrevia tions and acronyms section. Price: $14.95 r~~:::=~~;------l I Dept. 8M, 207 Kenyon Road, Champaign, IL 61820 I Please send me the new MICROCOMPUTER DICTIONARY under your I I 15 day no risk trial guarantee. If payment accompanies order we pay I all shipping and handling charges. (III. customers add 5% sales tax) ,
I Name I I Address I City State ______I Zip I Beach Ball
Software Editorial Il~TI by Carl Helmers staff
What a predica ment. You've bought this sph ere within the limits of your pe rception. PUBLISHERS box full of printed circuit boards, trans Usi ng an appropriate measuring tool you Virginia Green, President former iron and integrated circuit silicon. find that its diameter is 30 cm. The surface Manfred Peshka, General Manager After long hours paying attention to the is resili ent but hard. The ball slips out of EDITOR details of an intricate assembly process it is your hands and drops to the fl oor wh ere its Carl T. Helmers, Jr. PRODUCTION EDITORS "done." To the best of your abilities you've res ilience is confirmed by a healthy rebound. Beth Alpaugh ve rifi ed that the box does what it is After the examination, you put it back on Judith Havey supposed to do . Now it's sitting over there the pedestal. Again, the thought: what good ASSOCIATES on the bench (or living room table (or office is a beach ba ll ? It sits there with no life of its Hal Chamberlin desk)) plugge d into the AC wall outlet and own, not even condescending to wink an Dan Fylstra grinning like a Cheshire cat with a mouth LED at you. How could anyone possibly Don Lancaster full of LED or TVT tee th. So, now what do she ll out hard earn ed cash for such an Chris Ryland you do with it? Like many objects of some o bject? PRODUCTION DEPARTMENT bulk and substance, it seems so useless - but Lynn Panciera-Fraser, Manager is it? There are lots of human design ed Beach Ball Software Nancy Estl e Neal Kandel objects which at first sight appear to be But people do shell o ut lots of hard Peri Mahoney use less. But most turn out to have great earned money for beach balls. And people Bob Sawyer such as you and I are not fools when we buy poten tial va l ue wh ich can be rel eased by the PHOTOGRAPHY active and creative human mind. The secret a quality beach ball. We know beach balls Ed Crabtree of use and enjoyment is the application of are useful thro ugh o ur appreciation of fu n Bill Heydolph that most characteristically human capacity and adve rtising of the products. The beach DRAFTING to think. The ho bby created about these ball is the basic "hardware" required to pl ay Bill Morello artificial "brains" is an excellent training numerous ga mes; beach ba ll s are even used TYPESETTING ground for the human brain - one of the o n occasion for more practical tasks. The Barbara Latti, Manager secrets of its ap peal. beach ball is a wide ly distributed standard Marge McCarthy product with a simple design. Very little user PRINTING documentation is supplied by the manufac Biff Mahoney But Then, What Good is a Beach Ball Either? INVENTORY CONTROL turers and distributors of beach balls. The As an example of a simple object which Marshall Raymond, Manager wide acceptance of the beach ball is due to requires creativity to realize its potential, Kim Johansson the numerous applications inherent in its consider a child's beach ball. Im agi ne for a CIRCULATION des ign. These applicatio ns await the creative moment that your newly constructed com Judy Waterman, Manager minds of human beings who decide what to Pat Gei lenberg puter kit is sitting on its pedestal and begins do with the ba ll and how to do it. Any ga me Dorothy Gibson slowly to change into a beach ball through o r recreation which uses the beach ball as a Pearl Lahey some advanced technological " magic. " Its prop is an example of the "beach ball Deborah Luhrs corners begi n to round, the edges smooth software." Such games may have been made COMPTROLLER out, and after some mome nts of transforma up ge nerations ago and stored in the form of Knud E. M. Keller tion it is a jolly round beach ball having the word of mouth learnin g, printed books or same general properties the computer had: it magazines on the subject. Or, t hey may be sits there looking useless to the skeptic. made up or reinvented spontaneously and As an intelligent and active bein g, never recorded at all. Whatever the source, curiosity is one of your most admirable the game and its rul es form a method of traits. So you walk over to the pe destal, pick usin g the beach ball which takes advantage up that beach ball and begin a thorough of its properties, but is not in any way built examination of its characteristics. What do into the device. you find? As you pick it up you verify that So havin g temporarily approached the it is a solid object which has the expected problem from the point of view of a beach weight of a beach ball. You rotate it about ball, let's invert the transformation and turn several axes and verify that it is indeed a the object back into a computer. We still
9 have not solved the problem of where to get employ the computer. It might be that you the specific creativity required for the com us e the compu ter si mply to improve the puter software, but the beach ball analogy efficiency of some menial task, or you might provides a usefu l model. use the computer in an app li cation - such as A computer system, like a beach ball, is complex interactive ga mes - which would an incomplete system no matter how fu ll y have been impossible to perform minus the A manufacturer who supported by manufacturers' software. No com puter's intelli ge nce. Like any activi ty, supplies a series of manufacturer can tell you what you want to you get out of a computer rewards which are interesting sample pro do with the mac hine in complete detai l. The in proportion to the effort app li ed to under grams to illustrate the use manufacturer can supply suggested uses an d stand and "get into" the activity. build in features which make certain uses of his processor and With computers - as with beach balls - it inherently easy to program, but ultimately system is providing you is often possible to find a starting point in the us er of the computer must decide what this area of app lications and software. with a valuable service .. . to program or when to use the programs Creativity of the individuals who have pre available. The beach ba ll system is com viously thought about the subjects involved pl eted when the beach ball user decides can often be useful as a starting point. By upon a particu lar ga me or practical applica seei ng concrete examples of the uses of the tion in which the beach ball is a key computer systems, you can acquire a element. It might be that the beach ball valuable basic understanding of what can be simply makes the ap plication easie r to per done. One obvious sou rce of such informa form, or it might be that the beac h bal l is so tion is in the form of BYTE articles. crucial that the application wou ld not even Another form is in the user support have been possible without that bal l. The packages provided by manufacturers. A man computer system is also completed when ufacturer who suppli es a series of interesting you - the user - decide how you want to sample programs to illustrate use of his processor and system is providing you with a valuable service - you find out how things are done with his computer in specific and detailed examples. One excellent example of BOMB: BYTE's Ongoing Monitor Box such a service is the documentation which BYTE would like to know how rea ders evaluate the efforts of can be purchased for the assembler and text the authors whose blood, sweat, twisted typewriter keys, smoking editor programs of the SCELB I computers rcs and esoteric software abstractions are reflected in these pages. complete listings of the programs with BYTE will pay a $50 bonus to the author who receives the most detailed expl anati ons and design information points in this survey each month. (Editor Helmers is not eligible for the bonus.) The following rules apply: are provided in the manu als for these SCE LB I program products. When evaluati ng 1. Articles you like most get 10 points, articles you like least get a computer system, look fo r such examples o (or negative) points - with intermediate values according to in the documentation and compare the your personal scale of preferences. 2. Use the numbers 0 to 10 for your ratings, integers only. offerin gs on this poi nt. There are other 3. Be honest. Can all the articles really be 0 or 10? Try to give a sources of information about the creative preference scale with different values for each author. us es of the computers of the world. Direct 4. No ballot box stuffing: Only one entry per reader! information can often be acq uired in the Fill out your ratings, and return it as promptly as possible along context of the computer club, an assoc iation with your reader service requests and survey answers. Do you like an of users for the pu rpose of so lvin g problems, author's approach to writing in BYTE? Let him know by giving him exc hanging ideas, fi lling in gaps in a crack at the bonus through your vote. knowledge, etc. When you tal k to your technological neighbor about wh at he or she Page LIKED is doing, you can get valuab le information No. Article LEAST BEST on the possibl e applications of your 12 Baker: Mini-Microcomputer 0 2 345 6 7 8 9 10 machine; and of course your neighbor 26 Loomis: Light Pens 0 2 3 4 5 6 7 8 9 10 rece ives similar benefits in return. 31 Warren: Horror Story 0 2 3 4 5 6 7 8 9 10 It is this kind of exchange of creativity 32 Helmers: LIFE line 4 0 2 3 4 5 6 7 8 9 10 and ideas among interested individuals wh ich 42 Lau: Kitchen Information System 0 2 3 4 5 6 7 8 9 10 will make the personal computing fie ld into 46 Haller: Golf Handicapping 0 2 3 4 5 6 7 8 9 10 50 Dittrich: Op Code Table 0 2 3 4 5 6 7 8 9 10 a well developed facet of our civili zation, 52 Helmers: Blinking Lights 0 2 3 4 5 6 7 8 9 10 growing out of the scattered and isolated 56 Helmers: Wire Wrapping 0 2 3456789 10 efforts of individuals who pioneered the 60 Luscher: Memory Address Space 0 2 3 4 5 6 7 8 9 10 activity. One of the main reasons for BYTE 64 Peshka: K or k? 0 2 3 4 567 8 9 10 magazine's very existence is to help foster 92 Hogenson: CT-l024 Kit Review 0 2 3456789 10 this transfer of information, to give our readers the knowledge and ideas useful as creative starting points for personal ap pl ica tions of computers. -
10 solder less. DeSlgnmore. Whether youre test your operating circuit. we can fill them. For a full-time engineer With Desi gn Mate 1. hooking larger capacity, save time with or spa re-time up (or cllanging ) a circuit is as ou r Proto-Board " series-660 to hobbyist. there are simple as pushing leads into 3060 terminal points. with or on ly so many hours holes on tile breadboard . Rugged without bu ilt-in regu lated power a day you can 5-point contacts insure reliable. supplies. For small er appli ca- spend designing low-res istance connections ,' tions, use 1 or more and bui lding between resistors. capacitors. of our handy OT circuits . So why transistors . . even I Cs in TO-5 Sockets and Bus TI)e soldering iron. not make the most As a design looi. or DI P packages. And short it's obsole te . /" ,~ Strips, lockin g of your time? lengths of soli d #22 AWG wire 41 them together for Design circuits literally as make interconn ections easy I' infinite expand- fast as you can think. I nstead of wherever you need them . '\_I ability, as you need starting your next project with a At $4995 ~ complete. irs not Test DIP s w ith it. Starting at $2.00. p ower o n a n d so ld ering iron. save time by on lya time-save r. irs a money ~~~~! o,:, ~~ te v en Other ways to starting with our Design Mate™ 1. saver. too. ~~':.~~ ~~t ~i~Cuui t save time and In a compact ( 7 ~ " W x 6%"D x Larger capacity? Smaller Pro to-Cli p .... series. money. Proto- 3X"H) case with a conven ient capacity? Have it your way. Boards, OT Sockets and Bus sloping top it offers solderless Whatever your Strips are just the beginning of breadboarding at its bes t 790 bread boarding the many ways we can help make terminals: a continuously-ad just needs. you r life more enjoyable how able reg ulated 5-15 VDC 600 mA Prolo-Board t03. about a foolproof, shortproof 2250 so lderless su pply: and a DC voltmeter to terminals save way to test DI P lC's-even in monitor the internal supply or you time on every circuit you design. operating circuits-for just $450*? A full-featured. preci sion function generator for $6495*? A professional RIC bridge for $49.95*? A way to instantly see and monitor logic levels in an operating IC. without expensive scopes or elaborate procedures And more. to save you time. money and agg ravati on. D esign M al e 2: versatile function Time is money: generalor. only S64 . 95~ Start saving it. Ask ...... - DeSig n M ale 3: your CSC dealer Precision RI C to show you how to solder bridge. jusl S49.95~ less. design more and take the drudgery out of your electronic li fe . Or send for our free catalog and dealer li st ' M anufacturer's recomme nded retail .
CONTINENTAL SPECIALTIES CORPORATION
44 Kenda ll Street. Box 194 2 New Have=$=n. CT 06509 . 203-624-3103 TWX : 710-465-1227 West Coasl office: Bo x 7809. San Francisco. CA 94 11 9 · 41 5-421-8872 TWX : 910-372-7992 Canada: Le n Finkler Ltd .. Ontario
c 1975 C o nlinenl al Speciailies Corp.
11 Digital Equipment Corporation has a new addition to the microcomputer market. Designated the LS 1-11, it is a complete 16 A New bit microcomputer system o n a single 8.5 inch by 10 inch (21.6 cm by 25.4 cm) printed circuit board, combining the instruc tion set of a PDP-ll /40 with an under Mini - Microcomputer $1000 price. A 3.5 inch H by 19 inch W by 13.5 inch D (8.9 cm by 48.3 cm by 34.3 cm) boxed version of the LSI-11 is designed as an System off-the-shelf microcomputer system. Desig nated the PDP-11/03, it consists of an LSI-11 microcomputer, serial line interface, power supply, and a mounting box designed to mount in a standard 19 inch cabinet. Removing the front panel exposes the LSI modules and cables allowing replacement or installation of a module from the front of The Digital Equipment the PDP-11 /03. The power supply has three front panel switches and indicators accessible through a cutout in the front Corporation LS I-II panel. The lights and switches are still attached to the power supply and functional when the front panel is removed. Input power of the PDP-11/03 is typically 190 Watts at full load.
LSI-ll Evolution The processor, memory, device interfaces, backplane and interconnecting hardware of the LSI-11 are all modular in des ign to allow Robert W. Baker custom tailoring necessary for specific appli 34 White Pine Dr. Littleton MA 01460 cation requirements. It was not intended to be a low end minicomputer, but to provide minicomputer capability to the new micro com pu ter appl ications.
12 To accomplish this goal, the LSI-11 was bus. Every device on the bus capable of designed to optimize system costs rather becoming bus master has a specific priority than component costs. A four-chip micro associated with its position along the bus. programmed central processor was selected When two devices request use of the bus to emulate the PDP-11 instruction set, simultaneously, the higher priority device allowing the inclusion of automatic dynamic wi II receive control. All data transfers on the memory refresh without additional cost. The bus are interlocked so that communication is microprogrammed processor also makes independent of the physical length of the feasible user microcode and an ASCII con bus and the response time of the slave so sole which will be discussed later. long as a bus timeout does not occur. Asynchronous operation allows each device Central Processor to operate at the maximum possible speed. The central processor module consists of Interrupt System the microprogrammed processor and 4096 words of memory, together with the bus Interrupt and DMA handling incorporates transceivers and control logic. The four c'hip two daisy-chained grant signals. This method microcomputer controls the time al location eliminates device polling to service interrupt of the LSI-11 bus for peripherals and per requests and establishes an interrupt forms all arithmetic and logic operations as priority. The highest priority device is the well as instruction decoding. Eight 16 bit, module located electrically closest to the ge neral-pupose registers can be us ed as microcomputer module. Only when a device accumulators, address poi nters, ind ex is not asserting a request does it pass grant registers, stack pointers, or other desired signals to lower priority devices. When an functio ns. Arithmetic operations can be interrupting device receives a grant, the from one register to another, from one device passes to the processor an interrupt memory location or device register to vector which points to a new processor another, or between a memory location or a status word (PSW) and the starting address device register and a general register. Data of an i nterru pt service routi ne for the devi ceo transfers between 10 devices and memory on The current value of the PSW and program the bus occur without disturbing the counter (PC) are stored on the stack. processor registers. The processor operates with the interrupt mask (PSW bit 7) set (1) or cleared (0). Bus When PSW bit 7 is equal to 1, no external device can interrupt the processor with a The bus, which is implemented on the request for service. The processor must be H9270 card guide backplane asse mbly, is the operating at PSW bit 7 equal to 0 for the data path which enables a complete system device's request to be effective. Inter rupts to be configured. This bus was designed to can occur only between processor instruc al low low cost per ipheral interfaces for tions since they change the state of the microcomputer applications, rather than to processor. DMA operations, on the other support the wide range of peripheral config hand, may occur between individual bus urations common to large minicomputer cycles since these operations do not change systems. The processor module is capable of the processor state. driving six device slots along the bus without One signal line on the bus functions as an add iti onal termination, as provided with the external eve nt interrupt line to the H9720 backplane. Devices or memory can processor module. When connected to a 60 be installed in any location along the bus, as Hertz line frequency source, this signal line most bus control and data signals are bidirec can be used as a real-time clock interrupt. tional, open-coll ector lines that are asserted When automatic interrupt dispatch (vec when low. The bus signals includ e 16 multi toring) is not needed, this line may be used plexed data/address lines, 6 data transfer as a common interrupt signa l. Although this co ntrol lines, 6 system control lines, and 5 necessitates device polling (as in earlier interrupt and direct memory access (DMA) computers, such as the PDP-8), device inter control lines. faces may now be slightly less complicated. Any commu nication between two devices A single connection on the processor module on the bus is in the form of a master-slave enables or inhibits the external event relationship. Only one device, the bus interrupt. When enabled, the device con master, can have control of the bus at any nected to this line has a higher interrupt point in time. The master device controls the priority than any device connected to the bus while communicating with another daisy-chained grant signals. device on the bus, the slave. Since the LSI -11 bus is used by the processor and all Power Fail/Restart 10 devices, there is a priority structure to To further increase the system flexibility, determine which device gets control of the several power fail/restart options are avail-
13 able. The power fail sequence is initiated upon sensing a warni ng signal from the power supply signaling an impending AC power loss. The current PSW and PC are pushed on the processor stack and a new PC and PSW are taken from a vector at location 24. Normally, with non-volatile memory, this routine would save processor registers, set up a restart routine, and halt. When only volatile memory is used, the registers cannot be saved but the power fail trap does allow an orderly system shutdown to occur. When AC power is restored, one of the four jumper selectable power-up options is initiated. The first option is loading a pro grammed PSW and PC from the vector at location 24. This would be used with non volatile memory to continue execution of the program at the poi nt where the power fail occurred or to restart the program at an arbitrary address with ROM program storage. If the BHAL T line on the bus (the halt switch) is asserted during this power-up sequence, the ASCII console microcode will be entered immediately after loading the PSW and Pc. The second power-up option causes an unconditional entry to the ASCII console routines. The processor can then be started by an ASCII console command allowing remote system starting without controlling the bus halt line. (More on the ASCII console later.) Alternately, the last two options allow program execution to begin at a specified address in either macro code or microcode. Memory The 4096 word memory on the basic CPU module consists of sixteen 4096 bit dynamic RAMs. This memory logically appears on the external bus while being physically on the CPU module. Being accessible to the bus allows external DMA transfers to take place to and from the basic 4096 word memory. Also, an optional jumper allows the CPU module memory to occupy either the first or second 4096 word block of the bus address space. Various memory modules are available for applications requiring more storage than the standard 4096 word MOS memory on the processor board. Those offered include a non-volatile 4096 word core memory, a 1024 word static RAM, read-only memory (PROM/ROM) with a maximum capacity of 4096 words per board in 512 word incre ments or 2048 words in 256 word incre ments, and a 4096 word dynamic MOS RAM. A common disadvantage of using dynamic MOS memory is the necessity of refreshing the contents of memory at specific intervals. The refresh operation is required to replace the stored charge in each
14 QUICK .... The MODULAR MICROS what number is this? shifts each digit left automatically as a from MARTIN RESEARCH new digit is entered! The val ue on the display is also entered into an internal CPU register, ready for the next opera Here's why the new MIKE 2 and MIKE 3 .0 0.0 are the best values in microcomputers to .0. tion. Simply by pressing the write key, day! for example, the user loads 135 into If you have to read your microcomputer memory. 8008 OR 8080 like this-obit by bit, from rows oflights--the computer's making you do irs work. And if The MON ITOR program also allows the user to step through memory, one loca you have to use rows of toggle switches to Martin Research has solved the problem tion at a time (starti ng anywhere), to bothering many potential micro users program it, you might wonder why they check his programming. Plus, the Swap .... whether to go with the economical call the computer a labor-saving device! Register Option allows use of the inter 8008 microprocessor, or step up to the rupt capabilities of the microprocessor: powerful 8080. Our carefully designed the MONITOR saves internal register bus structure allows either processor to Contrast the layout of a typical pocket calculator. A key for each number and status upon receipt of an interrupt re be used in the same system! quest; when the interrupt routine ends, function; six easy-to-read digits. Why not the main program continues right where The MIKE 3 comes with an 8080 CPU design microcomputers like that? it left off. board, complete with crystal-controlled system timing. The MIKE 2 is based on We invite the reader to compare the pro the 8008. To upgrade from an 8008 to grammability of the MIKE family of an 8080, the user unplugs the 8008 CPU microcomputers to others on the mar board and plugs in the 8080 CPU. Then ket. Notice that some are sold, as basic he unplugs the 8008 MONITOR PROM, units, without any memory capacity at and plugs in the 8080 MONITOR all. This means they simply cannot be PROM, so that the system recognizes the programmed, until you purchase a mem 8080 instruction set. That's about it! ory board as an "accessory." Even then, adding RAM falls far short of a conve If the user has invested in slow memory nient, permanent MONITOR program chips, compatible with the 8008 but too stored in PROM. Instead, you have to slow for the 8080 running at full speed, enter your frequently-used subroutines he will have to make the 8080 wait for by hand, each and every time you turn memory access-an optional feature on the power on. our boards. Better still , a 4K RAM board Here they are! The m odular micros from can be purchased from Martin Research EASY I/O INTERFACE with fast RAM chips, capable of 8080 Martin Resea rch. The keyboard programs speeds, at a cost no more that you might the computer, and the bright, fully The MIKE family bus structure has been expect to pay for much slower devices. decoded digits display data and memory designed to permit easy addition of in addresses. A Monitor program in a PROM put and output ports. A hardware inter In short, the MIKE 2 user can feel confi makes program entry easy. And, even the face to the system generally needs on Iy dent in developing his 8008 system with two chips-one strobe decoder, and one expanded memory and other featu res, smallest system comes with enough RA M latching device (for output ports) or knowing that his MIKE 2 can be up memory to get started! three-state driving device (for inputs) . A graded to a MIKE 3-an 8080 system-in new I/O board can be plugged in any the future. Both the MIKE 2 system, with the popular where on the bus; in fact, all the boards 8008 processor, and the 8080-based MIKE in the micro could be swapped around in EASE OF PROGRAMMING 3 rely on the same universal bus structure. any position, without affecting opera This means that accessories--like our 450 tion. I/O addresses are easy to modify by Instructions and data are entered simply ns 4K RAM--are compatible with these reconnecting the leads to the strobe de by punching the 20-pad keyboard. Infor and o ther 8-bit CPUs. And, systems start coder (full instructions are provided); mation, in convenient octal format, ap this is in marked contrast to the clumsy at under $300' For details, write for your. .. pears automatically on the seven input multiplexer approach sometimes segment display. This is a pleasant con used. trast to the cumbersome microcom puters which require the user to handle FREE CATALOG! all information bit-by-bit, with a confus POWER & HOUSING ing array of twenty-odd toggle switches MIKE 2 and over thirty red lights! The micros described to the left are com MANUAL. .. plete except for a cabinet of your own Th is looseleaf A powerful MONITOR program is in design, and a power supply. The basic book includes micros require +5V, 1.4 A, and -9V, cluded with each microcomputer, stored full information permanently in PROM memory. The 100 MA. The 4K R AM board requ ires on the MIKE 2 MONITOR continuously scans the key 5 V, 1 A. A supply providing these volt board, programming the computer as system, with ages, and ±12 V also, will be ready soon. keys are depressed. schematics. Price for orders rece ived OPTIONS Say the user wishes to enter the number by November 15, 1975 .. $19 135 (octal for an 8008 OUTPUT 16 in I ncludes a certificate worth $ 10 towards A number of useful micro accessories are struction l. He types 1, and the righ t a modular micro system, good 90 days. scheduled for announcement. In addi tion, the MIKE 3 and MIKE 2 may be hand three digits read 001. Then he (Offer valid, USA only.) After 11 / 15: $25. presses 3, and the digits say 013. Finally purchased in configurations ranging from he punches the 5, and the display reads unpopulated cards to complete systems. 135. Notice how the MONITOR program ~ modular micros R martin research F For details, phone, write, or check the (Continued in column 3.) reader service card. Martin Research / 3336 Commercial Ave. Northbrook, IL 60062 / (312) 498-5060
15 memory cell which has been lost through addresses 000 to 376 are usually reserved for leakage currents. To eliminate most of the trap and device interrupt vector locations. control circuitry normally necessary to per Several of these are reserved in particular for form this memory refresh, the LSI-11 CPU software generated interrupts (TRAPS) as microcode features automatic refresh con shown in Appendix A. trol. When enabled by an optional jumper, the Instruction Set CPU refresh control causes execution of a All operations are accomplished with one microcode subroutine ap proximately every set of instructions rather than the conven 1.6 milliseconds; this operation refreshes all tional collection of memory reference in dynamic MOS memory in the system, not structions, operate/accumulator control just the memory contained on the CPU instructions, and 10 instructions. Single and module. While asserting a bus signal causing dou ble operand address instructions for all dynamic memories to cycle at the same words or bytes are used with a wide range of time, the CPU perform s 64 memory addressing modes, providing efficiency and references to refresh their contents. During flexibility in programming. The various the burst refresh time, external interrupts addressing modes include sequential forward are locked out while DMA requests are still or reverse addressing, 8-bit byte addressing, possible. 16-bit word addressing, and stack addressing. Maximum memory size of the 16 bit Using variable-length instruction formatting LSI-11 is 65,536 bytes or 32,768 words. allows a minimum number of words to be Usu ally the top 4096 words of memory on used for each addressing mode. members of the PDP-ll family are reserved Each processor instruction requires one for peripheral device control and data or more bus cycles. The first operation buffers, so the nominal maximum main fetches an instruction from the location memory size is 28,672 sixteen bi t words. specified by the program counter (PC). If no However, the us er is not required to dedicate further operands are required for executing the entire upper 4096 word space to 10, but the instruction, no further bus cycles are may implement only what is needed. Octal used. If memory or an 10 device is
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17 referenced, however, one or more additional niq ue and are shown in detai l in Appendix bus cycles are required. E. These includ e examining and changing the A special maintenance instruction is contents of memory and registers, calcula included in the LSI-11 instruction set to aid tion of effective addresses for relative and in hardware checkout. This instruction indirec t addressing, and the functions of stores th e contents of five internal registers halt, single-step, continue and restart. By in a specified bl ock in main memory. A exa mining the contents of an internal CPU diagnostic program may then be used to register, it is poss ibl e to determine which of examine the information and determine the the five methods of entering the console in te r nal operation of the micro-level routines was us ed. processor. Upon entering the console routine, t he The basic in stru ction set is that of the location of the next instruction to be exe familiar DEC PDP-11/40 without memory cuted will be printed followed by @. The mapping. Included are seve ral operations console routine will then wait for one of the normally not found eve n in other small 14 lega l command characters. Thus, the user PDP-11 processors, such as excl usive-or retains all the direct hardware control of a (XOR), sign extend (SXT), or subtract one conventional li ghts and switches front panel and branch (SOB). There are also two new and gains the ability to boot load from a instructions used to ex plicitly access the specified dev ice in byte transfer mode. processor status word (PSW) . With the optional extended arithmetic chip, full Interfaces integer multiply/divide and floating point The LSI-11 system includ es several arithmetic are also available. The instruction standard interface modul es to handl e a set is more comprehensive than that of the variety of applications. Currently both a PDP-11/05 whi Ie the execution times are a serial and a parall el 10 interface is avai labl e, little slower. Refer to Appendix B for a each as a single 8.5 inch by 5 inch (21.6 cm complete list of the LSI-11 instructio n set by 12.7 cm) PC board. Th e DLV-ll handl es and Appendix C for typical timings. a single asynchronous serial line between 50 The branch instructions make use of the and 9600 baud , while the DRV-11 provides condition codes (PSW bits 0 to 3) which are a full 16-bit parall el interface complete with set after execution of every arithmetic or two interrupt control units. The use of the logical instruction. This allows more two standard interface modul es makes it efficient use of memory by eliminating extra very simple to connect any desired device to instructions and temporary storage locations the LSI -11 bus. Standard devices such as typically used to check results of various teletypes, line printers, analog to digital operations. The res ult of eve ry operation is converters, etc., can be connected directly to directly accessible and can be modified the interface modules with no additional under software control by using any of the circuitry. A simple cassette recorder inter Condition Code Operator instructions. A list face can be made using the DRV-11 parallel of the four condition codes along with a interface, a UART chip, and a simp le speed brief definition of each is listed in Appendix indepe ndent recorder interface circuit such D. as that shown in Don Lancaster's articl e Serial Interface, page 30, in the Septemb er Software issue of BYTE .• Since the LSI-ll uses stand ard PDP-ll software, there is an extensi ve library of programs availabl e from DEC including Are you interested in buying one? diagnostic programs to check out your system after it is built. Th ere is als o a DEC This article has described the details of Users Society (DECUS) which makes ava il the LSI-77 computer by Digital Equipment able a complete library of various PDP-11 Corporation. For those interested in pur programs at reasonabl e prices . Ev ery LSI-11 chasing the board version of this computer, owner automatically becomes a memb er of the Southern California Computer Society is this organi za tion. organizing a group purchase for amateurs. This purchase will in volve an original equip ASCII Console ment manufacturer (OEM) quantity of 50 or The conventional front panel li ghts and more machines, on a basis of cost plus 2% switches are repl aced by an ASCII console/ minimum contribution to SCCS. For further ODT pac ka ge that operates with any stan information contact Hal Lashlee of The dard terminal device communicating through Southern California Computer Society, at a serial interface at a spec ific device address 273·682-3708. SCCS is organizing quantity at any available baud rate. Th e functions purchases of other computer equipment, and available are very similar to those used by is interested in making such offerings avail the fa mili ar PDP-11 Octal Debugging Tech- able through other computer clubs.
18 Branches:
BR Unconditional branch BNE Branch if not equal to III BEQ Branch if equal to III BPL Branch if plus BMI Branch if minus BVC Branch if overflow is clear BVS Branch if overflow is set BCC Branch if carry is clear APPENDIX A: TRAP VECTORS BCS Branch if carry is set
Signed Conditional Branches: Location Vector BGE Branch if greater or equal to III (Reserved) BLT Branch if less than III Time out & other errors BGT Branch if greater than III Illegal & reserved instructions BLE Branch if l ess or equal to III BPT instructions lOT instructions Unsigned Conditional Branches: Power Fail EMT instructions BHI Branch if higher TRAP instructions BLOS Branch if lower or same Console Input Device BHIS Branch if higher or same Console Output Device BLO Branch if lower External event line interrupt FIS option Condition Code Operators:
CLC Clear C Condition Code Bit APPENDIX B: CLV Clear V LSI-ll INSTRUCTION SET CLZ Cl ear Z CLN Clear N MNEMONIC INSTRUCTION CCC Clear all condition code bits
Single Operand - General: SEC Set C Condi tion Code B.i t SEV Set V CLR Clear word SEZ Set Z CLRB Clear byte SEN Set N SCC Set all condition code bits <::OM(B) Complement (l's) INC (B) Increment Jump & Subroutines: DEC (B) Decrement NEG (B) Negate (2's complement) JMP Jump TST(B) Test JSR Jump to subroutine RTS Return from subroutine Rotate & Shift: MARK Mark (aid in subroutine return) SOB Subtract 1 & branch if not III ROR(B) Rotate right ROL(B) Rotate left Trap & Interrupts: ASR(B) Arithmetic shift right ASL(B) Arithmetic s hift left EMT Emulator trap SWAB Swap bytes TRAP Trap BPT Breakpoint trap Multiple Precision: lOT Input/Output trap RTI Return from interrupt ADC(B) Add carry RTT Return from interrupt SBC(B) Subtract carry Miscellaneous Instructions: SXT Sign extend HALT Ha lt Processor Status (PSW) Operators: WAIT Wait for interrupt RESET Reset external bus MFPS Move byte from PSW NOP (no operation) MTPS Move byte to PSW Optional EIS: Double Operand - General: MUL Multiply MOV(B) Move DIV Divide CMP(B) Compare ASH Shift arithmetically ADD Add ASHC Arithmetic shift combined SUB Subtract Optional FIS: Logical : FADD Floating add BIT (B) Bit test (logical AND) FSUB Floating subtract BIC(B) Bit clear FMUL Floating multiply BIS(B) Bit set (logical OR) FDIV Floating divide XOR Exclusive OR Continued on page 22
19 NI~\\' I ... \'1 ,\\-1
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~~ ••I.II •• I ••lt·I ••11 r;., 2465 Fourth Street ~~.. ••• •• ~ Berkeley, Ca. 94710 Continued from page 19 APPENDIX C: TYPICAL INSTRUCTION TIMING
INSTRUCTION TIME (usee) COMMENTS
ADD Rl, R2 3 . 5 Register addressing
MOV R3,R0 3.5
MOV TAGl , 10 (R2) 11.55 Relative & index addressing
TSTB (R3)+ 5.25 Auto-indexed
BMI TAG 2 3.5 Conditional branch
JSR PC , 2 (R2) 8 . 05 Subroutine call
JMP (R4) 4.2 Jump indirect
RTI 10·5 Return from interrupt
Optional EIS & FIS Instructions: APPENDI X D: PSW CONDITION CODES MUL 24 - 64 Multiply
FADD 42.1 Floating add CODE PSW BIT CONDITION WHEN SET = 1 FMUL 52 . 2 - 93 . 7 Floating mult
N 3 If result were negative FDIV 151 - 232 Floating divide
Z 2 If result were zero
V 1 If operation resulted i n an arithmetic overflow APPENDIX E: C If operation resulted in ASCII CONSOLE/ODT COMMANDS a carry from the msb (most significant bit) or a 1 was shifted from the Isb Conunand Function (least significant bit)
< LF> Cl ose current l ocation; open next sequential location.
Up- arrow Open previous location .
Back-arrow Take contents of opened location as a rel ati ve address, and open that l ocation .
@ Take contents of opened l ocation as absolute address and open that l ocation .
r/ Open word at location r.
/ Reopen the last l ocation .
$n/ or Rn/ Open general register n(0-7) or S (PSW).
r;G or r G Go to location r and start program
nL Execute bootstrap l oader using n as device CSR. Console device is 177560 .
; P or P Proceed with program execution.
RUBOUT < DEL> Erases previous numeric character. Response is a backs l ash ('). Continued on page 24
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KIT ASM KIT ASM ONE·CARD COMPUTER : Motorola 6800 microprocesso r, 4K RAM, SPHERE 2: Includes all fea tures of SPHERE 1, plus seria l communica· $350 $520 $999 $1499' 512 bytes EPROM (containing a Program Development Sys tem ), a tions and audio cassett e or MODEM interlace . REAL·TIME CLOCK, 16 LINES OF DIGITAL 1/0 , hard wired ROM Monitor, and a seria l type interface. This is the 100·quanlity price. 1765 2250 ' SPHERE 3: Includes all the features of SPHERE 2, plus memory ex tended to the hobby user for a limited time on a single uni!. totaling 20K which is sufficient to run fu ll extended BASIC Language .
CPU BOARD: Motorola 6800 microprocesso r, 4K RAM, 1 KEPROM 522 622 6100 7995' SPHERE 4: Includes all of the features of SPHERE 3, except the (containing an EDITOR, ASSEMBLER, DEBUGG ER , COMMAND casse tte has been replaced by an IBM-campa table Dual Floppy Disk LANGUAGE, CASSETTE LOADER, D U MPER , UTiLITIESI, and a REAL System . This system includes a Disk-operating System and BASIC TIME CLOCK. Language and a 65 lPM line printer.
SPHERE 1: Includes the CPU BOARD described above, plus 512 860 1400' (\'arious) OTHER SPHERE PRODUCTS: Light pen option ; full color and B/W character vi deo with fu ll ASC II keyboard and numeridcur sor video graphics system ; low cost Dual Floppy Disk System : and full keypad, power supply, chassis. manuals and associated parts. line of low cost peripherals.
"This ASSEMBLED SPHERE System includes the complete chass is. and video monitor as pictured below.
~ ~ SIlI-iEFlE CORPORATION 791 South 500 West Dept. 129 (801) 292-8466 Bountiful, Utah 84010
23 Continued from page 22
BUS A collection of parallel data paths PC Program Counter. A register and power I ines used to which contains the address of the interconnect the various elements next instruction to be executed. of the system, including the central processor, memory, and all peripherals. POWER·UP Two wire jumpers on the CPU SEQUENCE module select one of the four BUS Bus timeouts or bus errors occur possible power-up modes: TIMEOUT whenever the controlling device on the bus (the bus Masted does OPTION POWER-UP not receive a response from the o PC at 24, PSW at 26, or HA LT add ressed device (the Slave) 1 ODT - ASCII Console within a certain length of time. In 2 PC = 173000, or HALT general, these are caused by 3 Special processor microcode attempts to reference non-existent memory or The power-up sequence is peripheral devices. Bus error traps initiated upon supplying power to cause processor traps through the the processor module or on trap vector address 4. restoration of power after a temporary power fail has DMA Direct Memory Access. For high occurred. speed devices, memory may be accessed directly through the bus without the use of program PSW Processor Status Word. Contains controlled data transfers. information on the current status of the processor including the JUMPER The CPU module contains priority mask (bit 7) and the SELECTABLE locations for six wire jumpers to condition codes (bits 0 to 3). OPTIONS control the various operating options as follows: STACK An area of memory set aside by 1. Two wires select which of the the programmer for temporary four possible power-up options is storage or subroutine/interrupt desired. These are normally set to sevice linkage. The stack uses the restart through vector location 24 "Last In - First Out" concept; (so the LS 1-11 acts as a standard thus various items may be added PDP-11 ). to a stack in sequential order and retrieved or deleted from the 2. One wire jumper enables the stack in reverse order. Stack starts external event (or real-time clock) at the highest location reserved interrupt feature when inserted. for it and expands linearly downward. In the LSI -11, register 3. One wire jumper enables the 6 is reserved as the hardware stack automatic dynamic memory pointer and must be initialized by refresh feature when inserted. the software. However, registers 0 to 5 may be used for various 4. Two wire jumpers determine program defined stacks as needed. the addressing of the 4K RAM memory located physically on the CPU module. TRAP Software generated interrupt.
Each wire jumper consists of a short length of bare copper wire VECTOR A unique address which points to soldered between two designated a reserved set of locations (2 holes in the PC board. words) for interrupt or error handling. The first word contains MACROCODE The instruction set which the the starting address of a service programmer sees and actually uses routine (a new PC) while the to implement his program, such as second holds the new PSVV to be the PDP-11 instruction set in this used by the service routine. case.
MICROCODE The low level instruction set used VOLATILE Volatile memory, such as RAM, in a microprogrammed processor MEMORY will not retain useful information to "emulate," or execute, the without power applied macrocode. Microcode is more continuously . Non-volatile primitive in function, but memory, such as core or ROM, executes at a higher speed than will always retain its information the macrocode. with or without power applied.
24 elll nlla! 4K - $115' 8K - $401' 11K - $561' 16K - $6.6'
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The SPHERE Memory board. Is designed to hold 16K of memory on one board. 2107 A-8 memory chips are used on this board and are designed in 4K increments to allow choice of 4,8,12, or 16K. Each memory chip is socketed and is delivered to you completely assembled and tested. The PC memory board connects to the CPU board tri-state buffered bus cables. The memory locations are strap selectable as to order of addressing. Those memory mania purchasers of 12 or 16K who have, or who buy, any SPHERE Computer System will get absolutely free the SPHERE extended BASIC com piler. All documentations will be included. IT'S ALL DYNAMIC MEMORY!
SPHERE CORPORATION I I.------~ Dept. 130 I 791 South 5 00 West I Bountiful, Utah 84010 I ~ I Dear SPHERE: I Yes! The facts j've read have convinced me! I
I 0 Pl ease ru sh me more details on your memory board. I I D Please rush me more details on your low-cost computer I system and periph era ls. (Specific questions, any, are 'W if I I attached.) I Print Name: I I Address: I SIlI-lE~E I City and State ' I CORPORATION Z,p Code. Phone· ______791 South 500 West Dept. 130 (801) 292-8466 ~------______I Bountiful, Utah 84010
25 ...... · . "" ...... ;l ;;i111111W11 ;;;; ;;::.~!!..... !~~ ~ ~~~ll!!m;:.. ":1~~ :~~::' ...... " , ...... ,"" ...... ~ITT£H Cf4 8' DIM ...... """""""," ...... , ...... · '" ...... """ ...... ·...... ~ImH (II 4' DIM · " '" ...... , ., ., . '" ••••••••••••••••••••••••••" " ... I. ••••. • •• ...... '" ...... ,., . "...... , ....::. .: ...... ::::...... : ... : ...... : .:::::::...... ::::::: .:::::::: :::::::: ...... Photo 1: The ease of removing just one dot from a ...... : :: :::::.. .:. .... ::::: .::::::::: full field display depends upon the display size...... The author's X-V display has an adjustable size ::: : \\\~~\~~ ~g~~gmmmmlm~:::::: :::::::::::::::: control which was used in preparing this picture. Let There Be Light Pens
Sumner S. Loomis With only a few components and a few Loomis Laboratories hours of construction you can add a versatile Route 1 Box 131A light pen to the oscilloscope graphics inter Prairie Point MS 39353 face which has been described in the October 1975 issue of BYTE, page 70 ff. By holding the light pen to the face of the cathode ray tube (CRT), a point may be added or removed. This eliminates the awkward and time consuming effort required when using a program or manual switches to change the dots on the screen. The resolution and capability of the light pen are dependent on two characteristics of the CRT. The brightness and the size of the display tube will determine how easily you may add or remove one dot. An idea of the effect of display size may be had from photo 1. The word Test was written twice on a 12 inch (30.5 cm) black and white TV picture tube configured as an XY display like an oscilloscope. The top word was written with the display adjusted to an 8 inch (20.3 cm) size, and the lower word was written with a 4 inch (10.2 cm) display. Each letter was written with only one stroke of the light pen without touch up or corrections. With some practice, and possibly several passes, one dot may be added or removed if the display measures 8 inches (20.3 cm) or more. Further improvements to the pen are required with smaller displ ay tubes. An Photo 2: The light pen can be used in an "erase" mode by filling the screen with "on" advanced circuit that greatly improves the dots then selectively removing dots with the light pen. The titles added to this picture (and all the pictures in this article) were created with a separate character generator capability of the pen with small displays is which is not described. also described in this article.
26 The light pen can erase or draw depending on the setting of a switch. Examples of the two actions may be seen in photos 2 and 3. If the oscilloscope interface is adjusted for a high repetition rate, some smearing or carryover into the neighboring dot positions occurs. The author's system has a front panel control permitting ten repetition rates. A small improvement in resolution can be noted at the lower writing rates, as shown in photo 2. A frame consists of 64 by 64 dots.
Theory of Operation The light pen operates on the principle that brightness is quite intense during the actual interval that a particular dot is being written by the CRT's electron beam. Although phosphor will continue to emit light for some time, the brightness decays in an exponential manner after the writing beam has moved on to the next dot. Figure 1 illustrates the simple light pen Photo 3: The light pen can be used in an "enhance" mode by using a footswitch control to flood the screen momentarily when the light pen is in position. circuit. With proper adjustment of the sensi tivity control (and possibly the brightness control), the photocell in the tip of the light pen will sense the moment in time when a dot is written at the particular location of the light pen. At this instant, the photocell will conduct, biasing the PNP transistor which causes a short pulse to be conducted through capacitor Cl to the base of the NPN transistor Q2. If the pulse is greater than .6 V, this transistor will be driven into satura tion, and the Iight pen output will fall to .3 V. This output line is the connected to pin 5 of the oscilloscope graphics unit which PC·I R-I writes a 1 or a 0 bit (dot or no dot) at MFG PHOTOCELL CONTROL precisely the instant that the dot position TI H-35 1M R5 touched by the pen was addressed. RI 2N5138 TI H-38 2M IK TI L-63 5K The above procedure works quite well if CLAIRE 903 20K the dot to be changed is illuminated at the LIGHT-PEN time. With proper adjustment of the sensi OUTPUT 10 I PIN 5 tivity control, we can usually use an illum I I inated dot just above the point of action (it I 51 b must precede the dot in scan sequence) to LDDU d'DEPOSIT create a new dot in the next space. This SPST LIGHT PEN PC - I action of extending a line can be quite useful for drawing bar graphs on the CRT. This Figure 1: The simple version of the light pen can be constructed according to this mode of entry is possible because screen schematic. All resistors ~ w. persistence allows the light pulse to be carried over into two or three subsequent dot positions depending on the frame speed. RI 2.2K How can the photocell sense the dot's ~Rgu~~~~ CARD _----'\fVVo-----_---_....-_ ~O,~~~~LLOSCOPE R2 position if there is not any illumination to I K trigger it? This is accomplished by the flood -12V ------. R3 R9 5K circuit which is shown in figure 2. This 390-22K circuit overrides the normal Z-axis control and floods the screen with light by feeding a CI logical one signal to the Z axis of the display O.IJ. 27 C3 C4 +5V 10 PIN:! O.II'F 20I'F R7 IK RI Y R4 680 DDU 6 Q t R2 TEXT 1.5K I I R3 I lOOK I I I I MIN. PHONE R6 SI lOOK R5 33K Q 9)-t----' LIGHT PEN PC-I '----1------.------' Figure 3: By adding a pair of oneshots to the circuit, the ability to draw pictures is improved through a short data lockout period which avoids smearing. writing beam reaches that particular dot In figure 3 resistor R4 and capacitor C1 position. Releasing the footswitch removes control the length of the write pulse, and the flood and allows the data to be resistor R5 and capacitor C2 control the examined. wait time. For the 4528 CMOS oneshot, the The circuits just described will probably time of the pulse (T) measured in micro suffice if you wish to use the light pen only seconds is a function of resistance (R) and for occasional correction of data. If you plan capacitance (C) measured in ohms and extensive and detailed work, such as microfarads, respectively, as follows: cartooning or statistical data entry, a modifi cation of the circuit will allow you to tailor T 2.5 R C .85; the light pen's response to your own pa rticu = * * ** lar needs and system speed. The circuit shown in figure 3 is similar to the one shown where a single asterisk denotes multiplica in figure 1. However, it includes two oneshot tion, and a double asterisk exponentiation. multivibrators (contained in one CMOS The circuit shown in figure 3 also DIP). The first one produces a constant includes a switch and connections for using amplitude pulse of approximately 200 nsec the light pen with the author's text display duration wh ich is sufficient to bring about and editing system. Exact details for this the storage of a 1 or 0 bit in most versions of connection are not given here, as they will the 2102 memory (ICs 11 to 14 in the differ with the type and construction of the oscilloscope graphics interface). The second text display system. I found, however, that one delays the generation of another write the shift register type memories commonly command for .25 sec, giving the operator used in these systems require a much longer sufficient time to withdraw the pen from the write pulse than is necessary for the 2102 screen or move to a new location, before a memories. It was also desired to eliminate double or multiple dot can be drawn. Once the holdoff circuit (second oneshot) for this the two pulses have been timed in accor application. These changes are accomplished dance with a given system speed and the with switch 51 and resistors R9 and R5. If operator's writing speed, it becomes very these features are not desired, it is recom easy to draw detailed i mages with the light mended that R9 be replaced by a wire, R4 pen. changed to 4.7 k.Q and C1 to 20 pF. 28 Construction As is shown in the table accompanying figure 1, several different types of photocells are suitable for use in the light pen. The / Texas Instrument (TI) type H-35 or H-38 is a very small device with a built in lens. These were originally designed for use in punched tape and card readers, thus the small size. Their size, sensitivity, and restricted field of view make them ideal for this application. The high impedance of these devices, how ever, makes them somewhat slow for this appl ication, particularly at low brightness levels. The slow response time limits their use at the faster scan rates, and complicates the smearing mentioned earlier. Another device, the L-63 type which is available from Radio Shack (276-140 infared detector), was found to be considerably faster. Being a much larger device, however, it has a larger field of view, and much of its speed advan tage is lost to optical smearing. Models of Photo 4 : This shows a pen based on the TI type L -63 photocell, built using a marking both photocell types were built and tested pen case. by me, with only slight preference for the H-3S. With some careful masking, and possibly the addition of a small, short focal length lens (e.g., Edmund Scientific number 12050 cyl inder lens, or a small drop of clear epoxy), this photocell will probably perform better than the H-35 for this application. The Claire types 903 and 903-L were tried with only fair results. Any ball-point pen or felt-tipped marker can be reworked to make a housing for your light pen . Take a tour of the local stationery store to find likely candidates. The L-63 photocell was found to fit nicely into the end of a Graphi-100 marker pen which can Photo 5 : This picture shows an assembled light pen using a TI type H-35 (or H-38) easily be disassembled with diagonal cutters. photocell with a standard ballpoint pen housing. An example of the construction with the L-63 is shown in photo 4, and the H-35 assembly is shown in photo 5. Secure the photocell in place with epoxy adhesive after attaching the shielded cable. The cable can also be secured against damage from pulling by filling the entire pen with silicone rubber adhesive or ordinary house hold bathtub caulk. It is wise to keep the cable short, especially with the H-35 or H-38 photocells, to obtain maximum possible res ponse speed. I used an 18 inch (45.7 cm) long miniature coaxial cable leading to a miniature phone pi ug. If you are using the simple circuit of figure 1, the parts can be assembled on a small turret terminal board available at most electronic supply houses. This assembly is shown in photo 6. The circuit of figure 3 can be assembled in the same manner with the addition of a 16 pin DIP socket. R4, R5, C1 and C2 should be mounted in such a manner Photo 6 : This photo illustrates how the circuit of figure 1 can be assembled using a small that they can be changed easily (Cambion turret terminal board. The transistors and R5 are mounted out of sight on the rear side 601-1512 component clips are useful here) . of the board. 29 The sensitivity control may be conveniently mounted on the front paneL The operation of the light pen requires control of the inputs to the oscilloscope graphics unit. I have found that one of the most convenient ways in my system is through a set of manual data switches. This type of input was illustrated as a test fixture for the oscilloscope graphics interface in figure 5 on page 75 of the October 1975 issue of BYTE. In my system, these data input switches are shared with a Mark-B minicomputer front panel by means of an B pole double throw toggle switch. It is also possible to set up input codes to the oscilloscope graphics unit using software in the microcomputer system which drives it. In order to enter data with the light pen, a deposit switch is pressed whenever the pen is in the proper position for data entry. The deposit switch should be mounted in a convenient location near the display tube and light pen. In my system the light pen deposit switch was mounted next to the original deposit switch of the Mark-B com puter. Photo 7: Using the improved circuit of figure 3 reduces much of the over-writing of Using The Light Pen multiple dots which occurred using the original circuit of figure 1. This is an enhance To illustrate the use of the light pen, we mode picture. wi II cover the procedure necessary to draw a simple figure on the screen in the erase mode using manual controls. Set the switch register to 1000 0110 binary (turn scan on) and depress the deposit switch. This should produce random dots on the screen. Set the switch register for 10000010 binary (set Z on) and depress the deposit switch again. The screen will show a full field of dots. (If the Z axis polarity of your display tube is reversed, you wi II have to use the "set Z off" command (10000011 binary) to illuminate the screen.} Set the switch register for 1000 0010 (set Z on), but do not activate the deposit switch. Now bring the light pen in contact with the display CRT, and note that the dot or dots within its field of view are erased. To erase the entire screen and start over, simply press the deposit switch and repeat the above procedure. To write in the enhance mode (screen dark, writing illuminated dots), reverse the above procedure by wiping the screen clean with the "set Z off" command (while the scan is on), and after setting the switch register to "set Z on" without the deposit switch, proceed to write dots with the light pen. I n this mode, the flood foot switch must be periodically activated to provide the required illumination. Examples of the light Photo 8: This illustrates a cartoon drawn using the erase mode of operation with the pen's drawing capability can be seen in improved circuit of figure 3. photos 7 and B.• 30 Horror Story Not too long ago, researchers at Stanford "error-checking codes," and form an Jim C. Warren Jr. Medical Center in California were horrified on-going area of applied-mathematics Star Route Box 111 to discover that several years of data that research. In either case, partial redundancy is Redwood City CA 94062 were stored on magnetic tape had important in that it improves reliability, but disappeared. The tapes hadn't disappeared, req uires less additional storage than just the data. The discovery was made when full- or triple-redundancy. they attempted to retrieve some of the data First, the researchers thought (prayed) for analys is, but found only "garbage" that their tape decks were malfunctioning. recorded on the tapes. Even more disturbing Not so. Diagnostic checks were made and the was the fact that these tapes were supposed tape equipment was working properly. Next, to be ultra reliable. They had been especially the tapes were examined. Nothing was developed for storage of important research wrong with them, physically, and in fact, data and used a fully redundant recording new data could be recorded on them and technique for improved reliability. retrieved without difficul ty. They as ked Fully redundant recording is a storage others around the Medical Center if they had technique in which each data bit is recorded encountered similar problems (there are in two different locations. In this case, about 50 computers at the Stanford Medi cal DECtape TM was being used. This is tape Center). None had. Then they looked for that is 3/4ths of an inch wide and has six environmental causes, but there appeared to parallel data recording channels or paths. be none. The temperature and humidity The data recorded in the three channels on recorders, common to biomedical research one side of the tape is duplicated in the facilities, indicated no significant three channels on the other side. Thus, the fluctuations. There had been no fires, no tapes have half the data capacity that they chemical accidents, and there was no x-ray cou ld have, but their re li ability is signifi or high power electronics gear in use nearby. cantly improved. The tapes had bee n in their individual boxes, It should be noted that there are a just like the tapes for all of the other number of other possible redundant storage computer facilities in the Medical Center, techniques in use for improving reliability. and these boxes had been neatly stored on For instance, "triply redundant recording" the bottom shelves of a cabinet, well out of replicates each bit three times in three the way of possible harm. It was a most separate locations. Alternatively, depending frustrating puzzle. on the allowable bit-patterns that may be Finally, however, the mystery was solved. us ed to store data, "partial redundancy" It seems that the janitor had made his may be used. In this technique, a biannual floor polishing rounds, using a computation is performed on the explicit heavy duty rotary floor pol isher. The bit-pattern of each datum. The computation magnetic radiation from its massive motor, result requires fewer bits than the original in proximity to the low shelved tapes, had datum, but may be used to either replicate raised havoc with the bit patterns that had the original datum (thereby recovering it, if bee n recorded on the tapes. necessary) or to at least verify the The researchers now store their tapes on authenticity of the original datum. These are the top shelves. - referred to as "error-correcting codes" and 31 Ine Integrating graphics control commands Carl Helmers In LIFE Line 3, the design of the optionally be performed by depressing either DECODE routine of the LIFE program was the birth key or the death key at the same presented. DECODE is designed as a table time. Thus as many as three keys may be driven mechanism for selecting one of sensibly pressed simultaneously when several subroutines wh ich carry out the entering data. functions of the LIFE program's KEY The large number of combinations BOARD_INTERPRETER. However if you possible for the six bits which will be needed examine table 1 of LIFE Line 3 (see p. 51 of for six switches strongly argues . against BYTE #4), you will note one conspicuous making the software use a table driven and intentional lack: There are no routines algorithm such as DECODE. This is the which process the interactive graphics com reason why no cursor motion and data entry mands required to set up LIFE patterns on commands are found in table 1 of LI FE the scope display. Yet in LIFE Line 1, Lin e 3. Since each bit of the parallel several special purpose keys were introduced information from the motion control as manual inputs for cursor motion control switches can have an independent meaning, a and data definition purposes. Where is the specially programmed determination of missing part of the program which interfaces motion control actions uses less memory these keys? What are the hardware implica than the huge table which would be required tions of requiring a special keyboard? for all the combinations. Thus handling of Answers to these questions are the major motion control is left to the DEFAULT concern of LI FE Line 4. Integrating the routine which is called by DECODE when it graphics control commands is a combined fails to decode one of the commands in table hardware and software topic. The software is 1 of LIFE Line 3. (DEFAULT also handles that of the DEF AU LT routine that inter ASCII numeric inputs, as you'll see a bit prets several keyboard inputs not handled by later in LIFE Line 4.) DECODE; the hardware consists of the design of a special keyboard interface to Graphics Control Hardware Considerations automatically switch between an ASCII key For the hardware of LIFE, how can the board's 7-bit parallel output code and the need of this special set of input codes be LIFE graphics control keypad. reconciled with the need to input ASCII via The main requirement for LIFE cursor the same eight-bit input port? One answer motion and data control is that one, two or lies in the choice of an eight-bit format in three of the input keys can be depressed at which the most significant bit determines the same time. This capability is needed in what lies in the low order seven bits. With order to specify all the possible combina this format, one state of the most significant tions of motion control and optional cell bit indicates when an ASCII code is present birth or death data inputs. The individual in the low order; the other state of the most motion control possibilities (one key at a significant bit indicates when graphic control time) are the movements in four principal keyboard information is in the low order. directions: up, down, left or right. When two This choice of format is supported in hard motion control keys for perpendicular direc ware by the addition of a simple interface tions are selected at the same time, diagonal module which uses seven integrated circuits motion is the desired result. With either to switch between data sources and form of motion control, entry of data can debounce the motion control keyboard. 32 Graphics Control Commands Format: 7 6 5 4 3 2 o x c b u d right movement if one left movement if one down movement if one up movement if one birth/death (one/zero) change enable, if one, move only if zero unused one to indicate a graphics command ASCII Keyboard Input Format: 7 6 5 4 3 2 o o a a a a a a a ASCII characte) (7 bit) I zero to indicate ASCII Figure 1: Data forma ts for graphic control commands and ASCII keyboard input. The combined ASCII and control data prototype is currently using one of the A flip flop with preset and format is illustrated in figure 1. When the surplus Sanders 720 keyboards described in clear inputs can be used in value of bit seven of the interface is read as BYTE m.) The graphic control information place of a hand-wired set one, the pr ogram ming of the DEFAULT is derived through jack J 2 fro m the special reset flip flop. routine will always be entered and the low keyboard via the 7474 flip flops IC1, IC2 order bits will be analyzed as graphic control and IC3. These D flip flops are being used as information as shown by the upper diagram set reset flip flops by gro unding the clock in figure 1. The low order bits zero through line and employing the preset (PRES) and three represent the individual key states of clear (CLR) inputs for data and keyboard the motion control switches and the next acknowl edge functions respectively. The flip two bits, four and five, are encoded with flop outputs for bits zero to three go information on data entry from the birth directly to the data selector to define cursor and death switches. If the value of bit seven motion inputs. The flip flop output for bit is read as a logical ze ro, the program will four (birth switch) also is directly connected interpret the ASCII value of the low order to the selector. However, bit five of the bits through the DECODE routine of LI FE selector's cursor motion inputs is taken from Lin e 3, or through the DEFAULT routine if NAND gate IC4D which encodes a CHANGE the command is not in the table which drives ENAB LE signal when eith er birth or death DECODE. data input is indicated. (Note that the user The hardware needed to implement this of the LI FE cursor motion control keyboard special interface is shown in figure 2. The is on his honor not to push both birth and interface consists of a two way data selector death keys simultaneously - with this (IC6 and IC7) which determines whether the encoding logic, birth always locks out eight bit pattern prese nted to the system bus death.) One item derived from the cursor interface comes fro m the cursor motion control keyboard is a key pressed signal control keyboard or from the ASCII key produced by 7430 NAND gate IC5. This board. The ASCII data is routed straight to signal is inverted by IC4C and used to the data selectors from a jack (J 1) which control the data selector: If any key on the receives a ca bl e which connects to the cursor motion control keyboard is pressed, keyboard unit. (The LI FE Line system the ASCII keyboard will be locked out; 33 LIFE INPUT KEYBOARD JACK J2 1 +5V 1 I~ LO+ KO+ I 4 PRES 0 5 CJ LO - I 1 +5V ...L 3 I 1 1 . ~I,~~RR~22 ~* __ ~fPt~f;-ff-a~'~CI_7_4_7_49 ____~ ~ ______-, KI+ 1 ~()o ~ 10 PRES 0 LI+ S2=LEF;T dCLR C al LI- I 1 13 ...LII B I I R3+¥ fff 1 l /. ~1_~~~=-~~44P~;--a~5 ______~ ~L~2~+~ ______--, K2+ 1 ~ <> • ~ ;PRES _0 J S3=DOWN , I L2 - 1 I CLR C 0 6 1 +5V I ...L3 I I R4 fff IC2 7474 1 I ', ~1-';D~~ __~'0~~S--C~9 ____-+~~L~3~+~ ______, K3+ W <> PRES 0 ~ I U S4=UP! WCLR C ~ <{ \ U. I +5V 13 ...LII B I I IX I ~ fff J W ~"<>-+'~==~ __ ~1~4~I PR~E~S;--a~1,5~ __~+-~~L~4~+ ______~D~A~TA~+- ~~-+~~+-______--, K4+ I- Z 55= BIRjI'H HCLR C 0" L4- Cl 3 IC4D I p+5V I 0. 6 7400 IX I / I R6 10 IC3 7474 13 <{ K5+ 0 ~S6--D' EAT H PRES 0 1 II CHANGE L5+ ID I ~ CL R C QL B: 1 L 5 - 12 ./P':E"'N""'A-::B-:-L"'E-+-t--t-+-H H-+-----+-s-,v >- W I 13 mil K6+ ::.:: ~ IC4C R7 -u-- I 2 3 4 5 [6 111 112 7400 IC5~B 7430 2 5 II 14 13 106 21 5 II 141310613 B 10 U KEYBOARD CJ 12344321 12344321 Y ~ CHANGE A A A A B B B B 15 A A A A B B B B 15 POWER 1 BIRTH DEATH ENABLE DATA 1 000 0 t-'j"'" ~~~57 'I 7'.f'~7 r KEYBOARD I o I I 0 UND 4 Y 3Y 2Y IY 4Y 3Y 2Y IY 1 0 I 1 r. 7 1 I 1 I 12 9 7 4 12 9 7 4 GI l 1 WRITE- I IC4A 4 IC4 B J 6 ACKN- ACKN- I ~~~~3 ______~ , PULSE TO 2 J"L 5 1 KEY BOARD LOW HIGH I DEVICE FOR ORDER ORD ER KEYBOARD SYSTEM INTERFACE JACK JI DO 01 02 03 04 05 0 6 07 TO SYSTEM BUS INTERFACE 01234!i67 (IDLE STATE: 00000000) Figure 2: The logic diagram of a keyboard interface which implements the fonnats of figure 1. Resistors R1 to R7 are TTL pUIl up resistors. The value are not critical, and may range from 1 KO to 10 KO, J;.! w. otherwise the ASC II keyboard is connected computer's data bus, buffered by National and the cursor motion control keyboard is DM8833 Tri State bus transceivers is used. ignored. Note that the cursor motion input T he interface thus consists of two DM8833's has priority over the ASC II keyboard since it used to drive the bus, plus the address controls the data selector. selection logic needed to detect the address Finall y, to complete the interface logic of t he keyboard and produce the bus enable sections A and B of IC4 are used to buffer signal as we ll as the WRITE- signal. For a the computer-generated keyboard WR ITE computer based upon a kit, the input port signal which occurs when the computer logic will be in a standard form designed by writes data into the keyboard location. This the kit manufacturer. What is needed is a signal is used to reset the graphics control parallel input port, which might already f lip flops. The buffered version of the signal exist if your computer kit comes with a (pin 6 of IC4) is used to drive the acknow keyboard and parall el interface. ledge line of the ASC II keyboard unit. A separate buffer is recommended due to the Notes on Assembly unknown loading of the ASCII keyboard T he prototype version of the graphic device. In LIFE Line's design of a program, control keyboard is illustrated in photo 1. the logic of the KEYBOARD INTER The keys were made from conventional PRETER procedure is used to manipulate magnetic reed switches obtained from key the interface. board units found at a computer auction. What is not shown in figure 2 is the actual Any single pole single throw keyswitch can system bus interface. The design of such an be used; options on mounting are left to the interface must be done consistent with a ingenuity of the builder. The arrangement of given computer's data bus. In the prototype keys shown in photo 1 is designed so that system for LI FE Line, a Motorola 6800 t he cursor motion controls are at the top in 34 Photo 1: The graphics control keyboard of the LIFE Line prototype system. The group of four switches with arrows are cursor motion control keys. The two switches with captions "B" and "D" are the birth and death data keys, respectively. a group of four. The arrows were applied Photo 2: Detail illustrating wire wrapped assembly of figure 2 using a general using small pieces of self-sticki ng address purpose prototyping board. labels of the type often used by computer centers. The two isolated switches at the bottom of t his arrangement are the birth (B) routine whenever DECODE cannot match an and death (D) keys. The wiring of the input from this port to an entry in the keyswitches to the computer is accom COMMAND table. Decoding of the graphics plished through a multi-conductor bundle of control format and ASCII numeric wires trailing away at the bottom. This cable characters is left to the DEFAULT routine terminates in a dual-inline header plug which because of the systematic nature of these fits into a socket on the wire wrap board inputs. containing the computer and interface. How is this decoding done? One answer Photo 2 illustrates the wire wrap wiring of of course li es in the des ign of the DEFAULT the interface logic in the LI FE Line proto routine. DEFAULT is specified in a pro type system. cedure-oriented language in figure 3. Basically the DEFAULT processing fo llows Using The Control Information one of two paths of execution according to The purpose of the interface hardware is the hi gh order format identifier bit, bit seven to combine two keyboards into a single of the formats illustrated in figure 1. The input port with software distinguishing input data from the interface is passed to "who called" on the basis of the format DEFAULT in the va riable KEY which is set shown in figure 1. How does the LI FE at line 11 of KEYBOARD INTERPRETER software handle this data format? Recalling (see LI FE Lin e 3, figure 3). The high order the presentation in LIFE Line 3, the bit of KEY is tested by the AND o peration DEFAUL T routine is called by the DECODE of line 3. The masking bit string 10000000B 36 1 DEFAULT: 2 PROCEDURE; 3 IF (KEY AND 10000000B) NOT = 0 THEN 4 DO; / * GRAPHICS CONTROL INPUT CASE */ 5 CALL MOVECURS; /* MOVE CURSOR PER INPUT */ 6 IF (KEY AND 00100000B) NOT = 0 THEN 7 DO; / * CHANGE IS INDICATED */ 8 IF (KEY AND 00010000B) = 0 THEN 9 CALL LPUT(XCOL, YROW,O); /* TURN OFF POINT */ 10 ELSE 11 CALL LPUT(XCOL,YROW,ll;/* TURN ON POINT */ 12 CALL DISPLAY; /* SEND UPDATED LlFEBITS OUT */ 13 END; 14 END; 15 ELSE 16 DO; / * ASCII NUMERIC DEFAULT CASE */ 17 NUM = KEY - 30H; 18 IF NUM > 9THEN NUM = 9; 19 ZUM = 0; 20 DO FOR 1=1 TO 10; / * MULTIPLY = REPEATED ADD */ 21 ZUM = ZUM + ENTRY; 22 END; 23 ENTRY = ZUM + NUM; 24 /* ENTRY NOW HAS NEXT DECIMAL DIGIT ADDED IN WITH * / 25 /* A BCD SHI FT BY ONE PLACE 26 END; 27 CLOSE DEFAULT; selects only the high order bit of KEY so that the result of. the masked test will be zero if bit seven is zero, non zero if bit seven Data (8-bit bytes) used by DEFAULT at this level: is one. If the result of the AND is not equal to zero, the graphics control case will be NUM = temporary data byte used to hold a BCD digit for conversion to executed: the DO .. . END group extending binary. from line 4 to line 14. If the result of the ZUM = temporary data byte used to form the product when ENTRY is AND is zero, ASCII input is present so the shifted left 1 BCD digit by multiplication with 10, lines 20 to 22. character is forced into a numeric entry interpretation. The ELSE DO ... END Data (8-bit bytes) used by DEFA UL T but shared with the clause of lines 15 to 26 handles this alterna whole program. tive . KEY, XCOL, YROW, ENTRY Graphics Control Processing Subroutines Referenced by DEFAULT: The processing of the graphics control format is not at all compl icated. A pro LPUT . .. Routine (used als o by FACTS_OF _ LIFE) which placeS the cedure, called MOVECU RS is executed first bit value of the third argument at a location specified by the first two to decode the four low order bits of the arguments. Thus lines 9 and 11 define a new value for the bit at XCOL graphics control format and adjust the and YROW in the LIFEBITS matrix. cursor position. MOVECURS .. . The routine (see Fig. 11) which moves the cursor up, MOVECURS is specified in a procedure down, left or right depending upon the motion control switches which oriented language in figure 4. This routine are read into the low ord er bits of KEY. contains four IF statements which test the four motion control bits. Motion is achieved DISPLA Y . . .. The rou tine which copies LIFEBITS to the graphics for each logical one bit by simply adding or output device for viewing. subtracting one from the corresponding cursor position variable XCOL or YROW. Figure 3: The DEFAULT routine specified in a procedure-oriented Note that this software takes care of an language. invalid combination of up and down (or left and right) in a unique way: nothing happens . If contradictory commands are input, the 36 4 NEW ALTAIR " 1/0 CARDS III The pri ce of the A LTA IR 4K memory boa rd s trOIll I\I\ ITS was in correc tly li sted at $264 in the " M ITS-MAS " Christillas Cata log prin ted in Dece mber's Popular Electronics. Unfortunately, the price change ca ille after the catalog was printed . Th e A LTA IR -IK board provides 4,096 word s (bytes) of dynaill ic I ~AM (Rando m Access Mem ory) for the ALTA IR 8800. Eac h ind ividual boa rd contains memory pro tect c irc uitry an d address Two new A LTA IR 8800 I/ O boa rd s are now in production. se lec tion circ uitry for anyone of '16 starting address locations in Th ese inc lude a se ri al interface (B8- 2SI0) t hat ca n be ordered in crements o f 4K. The m ax illluill access time o f the A LTA IR -I I< w ith o ne o r two ports, and a pa rallel interfa ce (88-PI0 ) t hat ca n board was recentl y reduced f ro m 300 na noseco nd s t o be ordered w ith up to fou r ports. 200 nanoseconds. Ea ch po rt 01 the new Se rial in terface hoard is use r-selectable Dynamic Illemory was chose n for the ALTA IR 4K board beca use for RS232 , TTL, or 20 m illialllP current loop (Teletype). Th e it is generally fa ster and requ ires less current than static memory 88-25 10 with two ports ca n interface two se ria l I/ O devices, each (a 4K static ca rd that Illeets ALTA IR bus d ri ve spec if ications running at a different baud rate and each using a different elec req uires close to three t imes th e 5 volt c urrent of d ynaillic tricill interconnect. For exam p le, tlw 88-25 10 could be interfaced melllory). to an R5 232 CRT terillin al running at 9600 baud and a Teletype Other A LTA II~ 8800 memory opt ions include a 11< (1,024 words) runn ing at '11 0 haud. and a 2K (2,048 word s) static meillory carel. These low power An on-homcl. c rys tal-controlled clock allows each port to be static memory card s contain Illemory pro tect fea tures and have se t for one o f 12 baud rates: 37. 5, 75 , 11 0, 150, 300, 450, 600, a maxillluill access time of 850 nanosecond s. 1200, 1800, 24()0, 4BOO , o r 9600. Baud rates arc the speed at w hich datil is transfered between the computer and th e I/ O device. ALTAIR 8800 Memory Prices: 4K Dynamic ...... $195 kit and $275 assembled Each port "I the new Parallel interface provides '16 clata lines 2K Static. ... , ' ' .. $145 kit and $195 assembled and four controllable interru pt li nes. Each of th e data lines ca n 1K Static...... , ' .. , ...... $ 97 kit and $139 assembled be used as an input or o utput so that a single port ca n interface a terminal req uiring 8 li nes in and 8 lines out - or it ca n interfa ce two input devices such as a paper tape rea der and a keyboard PriceS. delivery a nd specificati o ns subject to change . or two output devices such as a paper tape pun ch and printer or ilny comhinatio n for custom applica tions. A ll data lines ilre fully TTL compat ible ALTAIR 8800 Interface Prices: 88-2S10 Serial Interface...... $115 kit and $144 asse mbled 88-SP additional 88-2S10 port ...... $ 24 kit and $ 35 assembled "Creative Electronics" 88-4P10 Paralle l Inle rface with o ne port.. . .$ 86 kit and $112 assembled MITS/ 6328 Linn N.E., Albuquerque, NM 87108 505/ 262-1951 88-PP additional 88-4P10 port . . ... $ 30 kit and $ 39 assembled MOVECURS: 2 PROCEDURE; 3 / * MOVE THE CURSOR BASED UPON THE FOUR LOW ORDER BITS */ 4 / * OF THE GRAPHICS CONTROL CHARACTER INPUT */ 5 I F (KEY AND 1000B) NOT = 0 THEN 6 YROW= YROW+ 1; 7 IF (KEY AND 0100B) NOT = OTHEN 8 YROW = Y ROW - 1 ; 9 IF(KEYAND0010B)NOT = OTHEN 10 XCOL = XCOL - 1; 11 IF(KEYAND0001B)NOT =OTHEN 12 XCOL =XCOL+l ; 13 / * NOW, IF THE SELECTED KEY WAS ON, THE APPROPRIATE */ 14 / * CURSOR POSITION REGISTER HAS BEEN CHANGED */ 15 CLOSE MOVECURS; Data (8-bit bytes) used by DEFAULT but shared with the whole program. See Table 2 of LIFE Line 3, BYTE # 4, pg. 55, for details. KEY, XCOL, YROW Figure 4: The MOVECURS routine specified in a procedure-oriented language. Decoding "who called" is cursor position variable in question is both mea ning. At line 17, a valu e of hexadecim al done in software by the incremented and decremented with a net 30, denoted 30H, is subtracted from the key DEFAULT routine. result of no change. Remember also that code. Sin ce valid numeric ASCII characters time delays are bui lt into KEYBOARD _ run from hexadeci mal 30 to 39, this wi ll INTERPR ETER to govern the speed of res ult in data running from 0 to 9 for va lid changes wh en keys are held down contin numeric codes. Th e test of line 18 exclud es uously. invalid co des by forcing a 9 value. (Unsigned Up on return from MOVECURS with the arithmetic is ass umed here so that all 8-bit newly updated position, the remaining integer values not in the range 0 to 9 wi ll be portion of the graphics control processing larger than 9.) Then the previous ENTRY consists of program logic to test for data value is multiplied by 10 using a repeated entry. If the change enabl e bit (bit five) has additi on loop at lines 20 to 22. The new a valu e of one, a change is indicated. Then if entry di git value is then added in to the low the data bit (bit fo ur) is ze ro, the current order at line 23. Note that ENTRY is a position in LI FEBITS is turned off, indi binary number, but that the di git being cating a death ; if the data bit is one, the d efaulted is entered with a decim al current position in L1FEBITS is turned on, weighting. (F or multiplication. an altern ative indicating a birth . Graphics control change to repeated addition in this case would be to processing is completed at line 12 wh en observe that 10 x = 8 x + 2 x. Thus using DISPLAY is called to pu t the new data out three arithmetic left shifts both twice and on the displ ay screen. eight times the original ENTRY cou ld be obtained and sum med produci ng the lO x Numeric Default Processing product.) In the alternative DEFAULT processing After execution of one or th e other of case of an ASCII character which is not the two paths determin ed by the format bit recogni ze d by the DECODE routine, the of the data in KEY , DEF AULT reaches its program will assume numeri c entry. In effect CLOSE statement and returns to DECOD E. wh at this mea ns is that any unrecogni zed non-numeric ASCII character wi II cause Where Does LIFE Stand? i nv al id data to be placed in the ENTRY In the course of LIFE Lin e through this register of the software since this li ttle installment, th e structure of the LI FE pro routine us es brute force to ex tract a numeric gram has been the major topic. L IFELin e 4 38 COMPUTER EXPERIMENTER SUPPLIES FACTORY FRESH-PRIME QUALITY PERFORMANCE GUARANTEED MICROPROCESSORS AND MEMORY 8008 ...... $ 35.00 ---- Commercial Grade-up to 35 ° C. 8080 ...... 135.00 These units are factory 2102 ...... 3.50 fresh, full spec devices. 2102-2 ...... 4.50 COMPUTER GRADE REGULATED POWER SUPPLIES All units are short-circuit proof, fold back current limited and with over-voltage crowbar protection. MD-15 MD-5-1 MD-5-3 MD-5-6 ±15 Volt at 200MA +5 Volt at 1 Amp +5 Volt at 3 Amp +5 Volt at 6 Amp Dual Tracking $24.50 $3 4.50 $44.50 $30.00 MICRO COMPUTER SUPPLY TTL INTEGRATED CIRCUITS COMBINATIONS All devices are factory fresh , full spec uniTs. For the 8008 7400 ...... 23 MD-08-+5 volt at 6 amp, -12, -9 at 200 7404 ...... 25 ma ...... $75. 00 7442 ...... 60 Forthe 8080 7447 ...... 95 MD-80-+5 volt at6 amp, ±12v at 200 ma ... $75.00 7448 ...... 95 For the Fairchild F-8 7475 ...... 60 MD-8-+5 volt at6 amp, +12 v at 200 m a ... $65.00 7490 ...... 60 For the M6800 7493 ...... 60 MD-5-+5 voltat6amp ...... $44.50 741 25 ...... 55 74126 ...... 55 All units are short circuit proof, fold-back current 74192 ...... 1.10 limited and with over voltage crowbar protection. 74193 ...... 1.10 All Prices Subject to Change Without Notice s~ os t devices s ~UARAN;EE Minimum Order $10.00 p Ippable Wi th ' Ipped With in 2 Add $1.00 to Cover Postage and Handling erlormanc In 2 weeks 4 hours II days. De l e gUa ranteed paYment reI' no t Send Check or Money Order (No C.OD.) T o : NO T ectlve On all . Unded ICE' Th ' Parts repi un its 10 . N . J. Residents Add 5% Sales T ax tha t hav~ n IS wa rranty a aCed a t no ch r 30 SOCke ts 10 at been So ld PPIles Only t arge. r YOUr incom' ered. You a Pa rts Ing inspect. mUs t use Ian tests. MICRO DIGITAL CORP. BOX 413, EDISON, NJ 08817. (201) 549-2699 A POWERFUL COMMERCIAL GRADE 8080 BASED MICROCOMPUTER SYSTEM REASONABLY PRICED STANDARD FEATURES INCLUDE: o A co.mmer~ial grade cabinet, made of heavy gauge aluminum, custom designed for this specific product. Rack mounting is available as a special option. o Lucite display panel with a photographically reproduced lei:l!nd and LED display mask. I n addition to standard li ghts and switches, the heavy duty front panel has an extra 8 program controlled LcD's. o Rugged commercial grade paddle switches backed up by reliable debouncing circuits. o Gold plated contacts on board edge connectors to assure corrosion free contact at a ll locations. o A heavy duty power supply to handle lots of extra cards, the power supply delivers up to 24 amperes at 8 volts, and 3 amps each at +16 and -16 volts. o A sturdy card cage to properly support up to 22 printed circuit boards. o Plug removable front panel board that eliminates the normal wiring harness between front panel and back plane. For special dedicated uses, the front panel tioard may be removed from the unit altogetlier and used only when program changes are desired. o A full line of peripheral devices to build truly powerful and complete systems. o An exclusive shared memory facility from the company that pioneered shared memory microprocessing. Shared me mory facilities a ll ow multiple microprocessors in the same cabinet to share the same memory, yet run diffe rent programs in parallel with each other. o A full compliment of board options. BASIC COMPUTER INCLUDES: 8080A Pr~essor Boar~l Front Panel COl;1tro l Board, lights and switches, power supply, Ex pander Board, Cabinet, ... and ... 256 BYTES OF RA,v, (on a 4K Board). PRICES : KIT ... $439 ASSEMBLED ... $621 OPTIONS: Rack mount, RAM & PROM Boards, Parallel & Serial I/O Boards, an 8 level Priority Interrupt/Clock Board, Shared Memory Boards, Interface Boards. PERIPHERALS: Flop'py Disk Drives, 3.2 Column/125 LPM Printer, 80 Column/300 LPM Printer, 50 Megabyte Disk Drive, 30 character per second Printer With Plotting Mode. TERMS: Check or Money Order, Bankamericard" Master Charge, 25% deposit on COD orders. On all orde rs under $1000, add 5% postage and handling. California residents add 0% tax . SEND FOR FREE CATALOG OF IMSAI PRODUCTS Contact : IMS ASSOCIATES, INC. 1922 REPUBLIC AVENUE SAN LEANDRO, CA 94577 (415) 483-2093 SPECIAL NOTICE TO ALTAIR 8800 OWNERS: If you would like to step-up to the commercial qualitr of an I MSA 18080, you will be pleased to know that your ALTAI R 8800 boards are "plug-in" usable-without modification-in the IMSA 8080 cabinet. Furthermore, by acq uiring IMSAI's unique Memory Sharing Facility, your ALTAIR MPU board and IMSAI MPU board can co-exist in the same cabin et, operate in parallel with each other, and share a ll memory In common. This is the technology that laid the foundation for I MSAI's powerful HYPERCU BE Computer and Intelligent Disk systems (recently featured in Computerworld, Datamation and Electronics magazines). 40 has introduced the first hardware co nsidera A bibliography of Scientific American infor tions - the special keyboard - as a mation on LIFE (all references are to Martin requirement in the specification of graphics Gardner's "Mathematical Games" column). control processing. LI FELine 5 wi II con tinu e the software theme by completing the October 1970: page 120. This is the initial specification of the LI F E program original LIFE article, including the design exclusive of the RESTORELlFE, definition of the Facts of LIFE, and SAVEll FE and INITIALIZATION pro illustration of numerous fundamental patterns. cedures which together form a major soft November 1970: page ll8. Answers to ware subject in their own ri ght. LIFE Lin e 5 several questions posed in the first will cover the DISPLAY, RUN, SETXLOC, article on the subject, including SETYLOC, LlFEDONE, and SETNGEN definition of the several varieties of "spa ceships." procedures as its main theme. Then the January 1971: pages 105, 106 and 108. series will turn to the hardware of the LI FE Continued progress on the LIFE system prototype in more detail, to provide front including answers to several a basis for the generation of actual unsolved questions and results of a executable programs which will run on the flurry of computer LIFE activity. February 1971: Special "Mathematical prototype system. The first major phase of Games" article on "celJular automata the LI FE Lin e project will be completed thcory." when it is possible to draw a LI FE pattern March 1971 : pages 1 08 and 1 09. Short on an osc illoscope output device using the note about progress made by Jolm Conway and R. William Gospers, plus cursor motion control keyboard, then illustration of a large scale flip flop initiate the pattern evo lution according to pattern which is delicately balanced the facts of LI FE as presented in LI FE Line and easily destroyed by minor distur 1. bances such as impact of a glider. April 1971: pages 116 and 117. The second major ph ase of the project Exa mples of fuses, the five cell cross will be the addition of the data management series, and announcement of Robert hardware and softwave facilities of the T. Wainright's LIFELINE newsletter. SAVELIFE, RESTORELIFE and November 1971: page 120. Short note on continued progress at the MIT AI INITIALIZE procedures. These facilities will Laboratory. enable the construction of initial patterns January 1972: page 107. The discovery from "standard parts" saved on a mass of the "eater" by Bill Gospers at storage device. As always, the aim of t he MIT. entire series of LI FE Line articles is to show This is an essential list of readily available how the bits and pieces of hardware and information on the LIFE game which interested software design fit together to produce a readers can research in any complete public or working appl ication system. _ university library. An Aside Regarding the Ultimate LI FE calculator, and a Turing machine pattern. LI FE on a 64 x 64 grid is an ac hi evab le The ultimate climax of the eve ning's demon project for the home brew computer stration was Bill's demonstration of a enthusiast. But it is far from the ultimate. disproof - by examp le - of John Conway's My thanks to Bob Clements of Lexin gton, conjecture that no LIFE pattern could grow Massachusetts for arrangi ng a demonstration without limit. The particular example he by R. William Gospers, Jr. , at the MIT used is a colossal moving glid er gun factory Artificial In tell ige nce Laboratory one recent - a pattern which leaves a trail of active Saturday even ing. When LIFE was first glider guns behind it as it travels slowly to widely publici zed by Martin Gardner in hi s the right on the display screen. This pattern October 1970 Mathematical Games column fill s the plane of the LI FE matrix with cells, in Scientific American, it helped set up a and the number of active cells increases in flurry of research work on the subject. proportion to the square of the number of Bill Gospers and his associates at the MIT generations the pattern has lived. After an AI Lab took the definition of John arbitrary length of time, an arbitrary region Conway's game and began constructing a of the pl ane will be filled with glid er highly efficient LIFE system running on a patterns emanating from the residue of Digital Equipment Corporation PDP-6 com glider guns produced by this LIFE machine. puter with a hi gh resolution 1024 x 1024 The programs which form the MIT LIFE position osci ll oscope display. This research system are run on equipment far beyond the tool was used by the MIT peo pl e to genera te range of price a hom e brewer could consider numerous mathematically interesting LI FE - but with the advances in technology it is patterns. These include such fundamental now possible to make a LI FE system which d'lscoveries as glid er guns, space ship d e monstrates many principles without factories, a binary transcend ental number breaking budgets. 41 Total Kitchen Information System Ted M Lau I want to o utline a plan for a total outputs. For example, box 1.0 takes grocery 7740 P Chalmette Dr kitchen information system (TKIS) sui tabl e prices from several markets and spits out a Hazelwood MO 63042 for implementing on a home computer. This list of bargains to be scheduled into meals. outline is the first step in the development Box 2. 0 acce pts a list of on-hand perishables, of TKI Ss of arbitrary complexity from t he in addition to t he output from 1.0, and simplest inventory modules to artificial yields a schedule of meals. Box 3.0 trans intelli ge nce modules (such as those suggested forms the meal schedule into the food by Richard Gardner in the October 1975 needed. Box 4.0 transforms raw, separate issue of BYTE). The functional approach foodstuffs into cooked fare. Box 5.0 turns a used here should all ow the reader to plan a meal into leftovers and garbage, and 6.0 complex system using small and manageable, turns garbage into clean Iin ess. " byte-sized" pieces, o r to interface ind epen Notice that I've ignored inputs that dently developed modules. appear unchanged as outputs, such as the This project began as a gr ipe li st my wife recipes consulted to pl 42 Figure 1: Functions of Total Kitchen Information System. components {a nd are thus fair game for fashi o n. Specifica ll y, TKIS pl ans to review a computer enhancement}, and that any large number of grocery item prices and to distinction between physical and informa call attention to those that meet a specials tional is strictly provisional {and is su bj ect to criteri on specified by the deve loper {1.1}. It erosion as computers expand their capa pl ans to call attention to items in inve ntory bi lities to manipulate objects, as in robotics whose perishabl e date fall s within the next and automation}. So the H chart incor meal scheduling period {2.1}. It pl ans to pOl'ates in to its comprehensive structure retrieve recipes based on key ingredi ents and both modules that are su bj ect to prese nt other characteristics such as casserol e, quick data processing so lu tions and modules that meal, Chinese, price-per-serving, nutritional must wait for future technology. {Readers valu es, etc., (2.4), and to reveal the recipe wi ll identify box 4.0 as the voice responsive ingredients not on hand, or to reveal o nly vending machine in t he rec room of the Star t hose recipes whose in gredients are a ll o n Ship Enterprise.} hand. It pl ans to help t he kitchen operator Notice t hat t he H chart says nothing decide whi ch markets to visit by simulating about computers. It describes my conce p the expenses of buying at vario us markets, tion of a very rigorous manual system that including labor time and gasol ine costs {3.2} . could be performed with paper and pencil. It It plans to calculate the q uantities of ingre purposely steers cl ear of computer concepts dients needed for recipes with adjusted to all ow you to be fle xibl e in making servings {3.1.1, 4.1}. It plans to collect me nu software and hardware design decisions. To and recipe evaluations {yum, good or echch} paraphrase: "Hardware and software may (6.4), along with keeping past meal pass away, but functions endure." The tasks schedul es and market receipts, for f ut ure to be performed by the TKIS remai n analys is in planning menus, purchas ing unchanged f ro m one system configuration to foods, budge ting, and dietetics. It even pl ans another. to sort the items o n each grocery li st into The H chart fu nctiona lly describes my store location o rder, so that by walking view of what must be done to get meals on through the store in a prescribed way the the table. I t is trigge red by specials and items will be e ncounte red in order (3 .3.3). perisnables in that it tries to cut costs by This is big o n my gripe li st: I hate carrying a pl anning meals usi ng bargains, and to reduce pencil to mark t he groceries I buy, a nd I also wastage by scheduling perishables in timely hate chasing allover the store to find the last 43 mately equal to the development time? To answer these questions, someone must RECIPES expand the effort to prepare detailed hard ware, software, and manpower estimates. For example, a recipe retrieval subsystem might use a CRT with keyboard to initiate a 24 search of the recipe file, and to display the results on the cathode ray tube (CRT) (see SEARC H FOR figure 2 for a schematic of the hardware and REC IPES an H chart of the software functions). Assuming a file contains 2000 recipes aver 2.4.1 I 2.4.2 I aging 500 B each, what are the cost and performance tradeoffs between a tape IN ITIATE SEARCHDISPLAY 1 FUNCTION ARGUMENT [ LIST system versus disk system? In order to make this estimate we must know, first, what 2.4.3 2.4.4 2.4.5 response time is acceptable to the kitchen GE T VALID operator. If the program reads records SEARCH J SEARCH DISPLAY ARGUMENT RECIPES RESULTS FILE sequentially, what tape speed is required? S EL ECTIONS [ J 1 What bandwidth is needed for data path A in Figure 2: Recipe Subsystem. figure 2 and how fast must programs exe cute? And so on ... 2 . How can the human labor required for data entry be kept below that required for the manual system? Data entry is the process by which humans, through the sweat of their brows, convert data into machine readable form so that the computer can do marvelous things with it and look like a genius. Data entry is probably one of the most costly items in the operating budget of the TK I5, and certainly one of the most boring. Table 1 lists the tables and files needed to implement a basic version of the TKI5. Of the tables, recipes and prices represent large data entry tasks at initial system startup and at periodic intervals. It would be very nice if the kitchen operator could acquire data in machine readable form (on cassettes or via the phone line). The book and magazine publishers could supply a periodic update of recipes and the markets an update of prices. 5 tandard formats woul d have to be Figure 3: Inventory Subsystem. developed for these interfaces, and a few unmarked items. I have become a customer base must be developed to provide hateful person just because my grocery li st is an economic incentive. unsorted. The files, on the other hand, originate within TKI5 and change continually with Beyond The Hierarchy Chart use, making it difficult to solve the data The H chart tells us what to do bu t not entry problem in the same way. For how, so where do we go from here? I would example, figure 3 describes a test design for hope that some of the readers will come an inventory module. The functions of this forward with data base and fi le designs, subsystem are to add a record (or a count) hardware specifications, and program of each purchased item to the inventory f il e descriptions. This is a massive project and corresponding to the storage location, to certainly in need of special talents and all ow retrievals by item, and to decrement diverse opinions. There are many well the inventories as items are used. The major known techniques for designing computer data entry requirements are to tell the systems, and I think it is sufficient for me to computer what was used and what was mention some of the potential problems that bought. may be encountered. An efficient way to do the former is to 1. Is the proposed TKI5 technically and sign ify what was used, instead of specifying economically feasible in a home? If not now, in detail what was used. By entering the will it become so in a time frame approxi- recipe name (say, recipe B), the operator 44 Table 1: Functional Storage Requirements. File Name Contents Possible So urce A. Tables 1. Prices grocery item prices by brand for each market Grocers 2. Recipes ingredients, instructions, recipe characteristics, Book and Magazine nutritional data, number of servings Publishers 3. Menus groups of recipes, menu characteristics Book and Magazine Publishers 4. Calendar dates, meal times, number of guests, other TKIS User requ irements 5. Markets market name, address, distance TKIS User B. Files 1. Inventories number and quantity of ingredients by location TKIS User freezer } also perishable items by I DNa. refrigerator shelf stock items - number and quantity of items, rate of use (salt, soy sauce) 2. Meal Schedule menu or recipes for each meal TKIS User 3. History past schedules and evaluations, market receipts, TKIS User etc. 4. Working Storage purchase list, grocery lists, etc. TKIS User says in effect that "the ingredients for recipe less accurately describe the condition of the B were used." This requires that the com computer than it does our emotional state puter have a recipe file for translating after the unthinkable has happened.) Backup "recipe B = ingredients D, E, F." If the manual procedures or alternate computer computer lacks this file, the operator must services must be provided to allow the enter the specific ingredients used. Thus a kitchen operator who has become dependent stand alone inventory subsystem is less data on the TKIS to function while the system is entry efficient than one integrated into a full down. Adequate system recovery and restart TKIS (a truism about systems in general). procedures must be designed, and a tech On the other hand, telling the computer nique developed for catching the computer what was bought can be handled rather up on what transpired while it was uncon neatly, by adhering to the rule that once the scious. The importance of these considera data is in machine readable form it should tions will depend upon the complexity and not be degraded out of same. Instead of a reliability of the hardware and software, but paper receipt, the bag person at the market must be conceived and designed as an will plop a cassette in your bag containing all integral part of the total system. the items you purchased and their prices. 4. Finally, assuming a TKIS was This cassette will have been produced by the developed, would a kitchen operator use it? market's point-of-sale terminal which so Besides being more efficient, less costly, and graciously performed the data entry chore all the other good reasons for which we for you by optically scanning your groceries. developed it, the TKIS must be flexible (In fact - or rather in fantasy - the market enough to allow for human inefficiency and won't even have to provide the cassette: you taste preferences. What if the TK I5 user will bring the purchase list created by TKIS doesn't want to prepare the scheduled meal on cassette to the store, insert it into the for the evening? TKIS must be able to take account of human inconsistency. computer at the front door which sorts and prints your grocery list in location order Summary (3.3 .3 and 3.3.4), and carry the cassette to the I have briefly outlined the functions I checkout counter for recording of your think a kitchen information system should receipt.) perform, and mentioned some considera 3. What does the kitchen operator do tions affecting its design. I hope this article when the system goes down because a disk will help catalyze development efforts in crashes, or the bus turns flaky, or a program what appears to be a fruitful home computer blows up? (This picturesque lingo seems to applications area. - 45 DUFFER Program Symbol Table: In order of appearance, DUFFER 002/000 ONCHO 002/217 NEXT I N 002/005 SUBRATE 002/221 INTEN 002/036 NOBRRW 002/230 Golf INUNIT 002/056 INCRD 002/327 GOAHEAD 002/071 ADD200 002/331 DROUTN 002/114 GODIVI 002/334 RSTRT 002/126 DIV1 002/341 CALCULA 002/134 ENDIVI 002/363 BUBBLE1 002/141 SCORE 003/000 BUBBLE2 002/146 I NCRC 003/040 Handicapping SWITCH 002/1 64 RNDLOOP 003/042 ADDSCOR 002/1 75 FRSTRND 003/050 ADDLDOP 002/203 ENDR1'lDT 003/062 Dr. George Haller 1500 Galleon Dr. Table 7: The absolute and symbolic assembly listing of the Naples FL 33940 DUFFER program written for an 8008 computer. Alm ost every golf club kee ps a roster of address octal code label op. operand conunentary its members with up-to-d ate golf handi 002/000 056 003 DUFFER un H (SCORE ) set up address of the 002/002 066 000 LLI L (SCORE) scor e data i caps . By using these handi caps, the members 002/004 125 OUT 12 SCELB! k eyboard handshake; with varying degrees of skill in the game can 002/005 111 NEXTIN IN read SCELBI keyboard; 002/006 240 NDA test status in bit 7; play competitively against each other. Many 002/007 120 005 002 JFS NEXTIN loop til ready. 002/012 125 OUT 12 SCELBI keyboard handshake; large clubs have go ne to se miautomatic 002/013 074 320 CPI "p" is it a "P"? 002/015 150 134 002 JTZ CALCULA if so then go process scores: computer services with terminals in the 002/020 0 16 000 LBI 0 clear input register B; 002/022 074 261 CPI "1 " is it a "1" digit? clubho us e but most clubs still appoint a 002/024 110 044 002 JFZ OUTTEN if not then skip next digit. of members which 002/027 133 OUT 15 send to special display; handicap committee 002/030 016 144 LBI 1000 initialize 100 decimal; meets periodi ca ll y, usuall y monthl y, to 002/032 300 NOP a02/0)3 300 NOP several NOPs here and there calculate each member's handicap. 002/034 300 NOP give room for mistakes; 002/035 300 NOP Basica ll y, a golf han di cap is calculated by 002/036 111 INTEN IN read SCELBI keyboard again; 002/037 240 NDA test status in bit 7; taki ng the average of the best ten of the 002/040 120 036 002 JFS INTEN loop for tens digit; 002/043 125 OUT 12 SCELBT keyboard handshake; twenty most recent scores for a regul ation 002/044 135 OUT 16 tens to special display; 18 hole ga me, subtracting the course rating 002/045 044 017 NOI 00001111B mask BCD digi t in low order; 002/047 022 RAL 2 times tens dig it; from this average, and multiplyi ng this 002/050 320 ICA save in C r egister; 002/051 022 RAL 2 x 2 x tens digit; difference by a factor of 0.85. This result is 002/052 022 RAL 2 x 2 x 2 x tens digit'" B x digit; 002/05) 202 ADe (2 + B ) x tens digit = 10 x digit; rounded off to the nearest whole number to 002/054 201 ADS add in 100s or zero from B; 002/055 310 LSA sav e lOs + 100s in B; become the handicap . As an exampl e, if the 002/056 III INUN IT IN read SCELBI keyboard again; ave rage of the pl aye r's best ten of his most 002/057 240 NDA test status bit 7; 002/060 120 056 002 JFS INUNIT loop for units digi t; rece nt scores is 95.2 and the course rating is 002/063 125 OUT 12 SCEI..BI keyboard handshake; 002/064 137 OUT 1 7 units to special display; 68.6, then the di ffe rence of 26.6 is multi 002/065 044 017 NDI 00001 111B mask BCD digit in 10worder; 002/067 201 ADS 100s + l Os + Is is the number; pli ed by 0.85 giving 22.6. Rounding gives 002/070 310 , LSA save binary score in B again; 002/071 111 GOAHEAD IN look for conunand code; thi s pl ayer a handicap of 23. 002/072 240 NDA test status as usual ; 002/073 120 0 71 002 JFS GOAHEAD loop for D or C command; The calcul ating of these handicaps offers 002/076 125 OUT 1 2 SCELBI keyboard handshake; a small bu si ness op portunity to the owner of 002/077 074 304 CPI "0" is it a " o " ? 002/101 150 114 002 JTZ DROUTN if so then go deposit score; a small computer. Sheets ca n be made up 002/104 074 303 CPI "c" e l se is it a "C"? 002/106 150 126 002 JTZ RSTRT if so then go ignore entry; with spaces for the members' names and 002/111 110 071 002 JFZ GOAHEAD loop til proper 0 or C is found; 002/114 371 DROUTN L>lS deposit score in memory l ocation; columns for the most rece nt twenty scores, 002/115 060 INL increment L r egister; the old and new handicaps. The handi cap 002/116 006 013 define" I" pattern; 002/120 133 OUTLA! 15" '" "J" into 100s digi t; 002/121 135 OUT 16 SEVEN 390n (7) "' " into lOs digit; 002/122 137 OUT 17 "J" into I s digit; OUTPUT SEG MEN T '5~~~~~ DI SPLAY 002/123 104 005 002 JMP NEXT IN begin input sequence again; LATCH DECODER MAN 4 OR 002/1 26 006 012 RSTRT define "I" pattern; LA! "'" 7475 744B DATAUT 704 002/130 133 OUT 1 5 "I" into 100s digit; 002/131 104 005 002 JMP NEXTIN begin input sequence again; DO '6 f---~ '5 ,...+-1++-++-1 002/134 006 014 CALCULA. LAI "U" define "U" pattern; 002/1)6 133 01 '5 f---~ OUT 15 "U" into 100s digit as marker; 002/137 061 DCL start the sort of scores; 02 '0 f---~ '01-~++I 7 I-I 03 9 f---~ 002/140 336 LDL counter gets initial pointer; 02 002/141 056 003 BUBBLE1 LHI H (SCORE) pointer to beginning of SCORE; f---~+-I ~3 I-I 002/14 3 066 000 LLI L (SCORE) also part of SCORE address; 13 14 - 002/145 323 LCD current pointer to C; 002/146 307 BUBBLE2 LAM fetch curr ent byte; 12 1.3 002/147 240 NDA set conditions; 002/1 50 060 INL point to next byte in bubble; 002/151 277 ePM compare next byte in bubble; 002/1 52 140 164 002 JTC SWITCH swi tch if need be; 002/155 021 Dec decrement sort count ; S TRO BE COD E 133 lsi. DIG IT 002/156 110 146 002 JFZ BUBBLE2 keep going on inner loop of sort; CO DE 13 5 2nd. DIGIT 002/1 61 104 175 002 JMP AODSCOR leave sort wh en done; CO DE 137 3rd . DIGIT 002/164 317 SWITCU LB M bubble sort involves a process 002/165 061 DeL of switching neighboring 002/166 307 LAM out of sequence pairs Figure 7: Each one of the three digits of the 002/167 371 I1 46 002/200 026 011 LCI 90 ten = nine plus predefinition. service furnishes these sheets to the golf club 002/202 307 LAM fetch f irst value before loop; 002/203 061 ADOLOOP OCL point to next value; to fill in all the information except the new 002/204 207 ADM add it f rom memory; 002/205 142 217 002 CTC INCHO if carry i ncrement h igh order. handicap. The handicap service then coll ects 002/210 021 DCC decrement loop count; the sheets on a monthly or other periodic 002/211 110 203 002 JFZ ADOLOOP keep adding until done; 002/214 104 221 002 JMP SUBRATE branch around subroutine INCHO; basis and returns them promptly with the 002/217 010 I NC HO INB inc rement B subroutine 002/220 007 RET is simplicity squar ed; newly calculated handicap. If done on a 002/221 2 40 SUBRATE NDA set f l ags; 002/222 024 267 SUI 267 octal low order of course rating; * monthly basis, a reasonable charge mi ght be 002/224 100 230 002 J FC NOBRRW if no borr ow then no adj u stment; 002/227 011 DCB high order adjust if borrow; from o ne to three doll ars per member per 002/230 320 NOBRRW LCA save low order in C; 002/231 301 LAB high order prepared; year depending on the length of the season. 002/232 024 002 SUI 2 octal high order course rating; * This income will not support much of a 002/234 310 LBA save high order in 8; 002/235 342 LEC start multiply by 8.5; computer service establishment, but could 002/236 002 RLC shift left high order of data; 002/237 330 LOA save r esult in 0; help in the purchase of some new 002/240 320 LAC fetch the low order of data; 002/241 240 NDA clears condition flags; peripherals. 002/24 2 002 RLC shift left low order ; 002/243 142 327 002 CTC I NCRO if carry then increment high order; In the author's case a SCELBI computer 002/246 320 LCA D/C !"lOW have twice the result; 002/247 303 LAD fetch high order; with its 8008 CPU was used with a standard 002/250 002 RLC multiply by 2 (4 x total) ; ASCII keyboard and a smal l home brew 002/251 330 LD A save high order; 002/252 302 LAC fetch low order; readout which cost less than ten doll ars for 002/253 2 40 NDA clear flags; 002/254 022 RAL multiply by 2 (4 x total); parts. A program equivalent to this one can 002/255 142 327 002 CTC I NCRO if carry then increment high order; 002/260 320 LCA save low order again; be written for almost any small home 002/261 303 LAD and again fetch high order; 002/262 002 RLC and multiply by 2 (8 x total ) ; computer. The diagram of the readout for 002/263 330 LDA and again save high order; each digit is shown in figure 1. 002/264 302 LAC and again fetch l ow order 002/265 002 RLC and again multiply by 2 (8 x total); The program requires fewer than 320 002/266 142 327 002 erc INCRD if carry then increment high order; 002/271 0 44 370 NOI 370 mask low order in 8 x total. bytes. Golf scores can range from 60 for a 002/273 320 LCA save low order in e again; 002/274 304 LAE fetch old original low order; super player to 150 for a complete duffer. 002/275 012 RRC divide by 2 giving .5 x ; 002/276 0 44 177 Nol 01111111B turn off high order bit; Regulation golf courses have ratings ranging 002/300 340 LEA save in E 002/301 301 LAB fetch origin al high order result ; from 65 to 75 which are always a matter of 002/302 240 NDA clear flags; record at the golf club. 002/303 0 12 RRC divide by 2 giving. 5 x; 002/304 310 LBA saVQ high order in 8 002/305 304 LAE fetch low order; The program to calculate the handicap on 002/306 142 331 002 erc ADD 200 if c arry, adjust low order; an 8008 is shown in table 1. The keyboard is 002/311 240 NDA clear flags; 002/312 202 ADC 8 + 0.5'" 8 . 5 x result; used to input the scores one at a time. If the 002/313 320 LCA save low order B. 5x in C; 002/314 142 327 002 CTC I NCRD increment 0 if carry to high order; first digit is a 1 then 100 (decim al which is 002/317 301 LAB fetch high order; 002/320 0 44 177 NoI 01111111B clear bit 7; equal to 144 octal) is loaded into register B 002/322 203 ADD add other high order giving 8.5 x; 002/323 310 LBA save back into B; and displayed on the left readout. If the first 002/324 10 4 334 002 JMP GOD I Vl branch around two subroutines; 002/327 030 !NCRO IND subroutine increments 0 register; digit is not a 1 then the score is less than 002/330 007 RET and returns almost instantly; 100, and this digit is considered a second 002/331 004 200 AoD200 ADI 100000008 turn on high order bi t if off; 002/333 007 RET and also return almost instantly; digit. The second digit is displayed on the 002/334 036 144 GODIVI LDI 1000 load 100 count in 0; 002/336 046 011 LEI 90 load 9 count in E; central readout. Multiplied by 10, it is then 002/340 301 LAB fetch high order of numerator; 002/341 310 oIVl LBA save high order in B; added to the contents of register B. The fin al 002/342 302 LAC fetch low order to A; 002/343 022 RAL divide by 2; digit is shown in the right readout and added 002/344 320 LCA save low order; 002/345 041 DCE decrement subtraction count; to the contents of register B. The operator 002/346 150 363 002 JTZ ENoIVI if zero, then end divide; verifies the score shown on the three digit 002/351 301 LAB fetch old high order; 002/352 022 RAL r otate left; readout. If it is correct, the key D is pressed 002/353 223 SUD here is the repeated subtract; 002/354 100 341 002 JFC olVl if no borrow then tr ia1 ok; which stores the score in memory and sends 002/357 203 ADD else fix up for false subtract; 002/360 104 341 002 JMP olVl and go back f o r more subtracts; the program back to look for the next score 002/363 022 ENOl VI RAL mul tiply low order by 2; 002/364 340 LEA save low order in E; to be entered. If an error has been made, by 002/365 006 377 LAI 11111111B load all ones into A; pressing key C the program goes back for a 002/367 252 XRC exclusive OR with all ones 002/370 320 LCA complements e; corrected score without storing the incorrect 002/371 104 050 003 JMP FRSTRNo jump around da ta; score in memory. After twenty scores are BLK 320 32 bytes for scores; * * 003/000 SCORE entered, the key P starts the calculating 003/040 020 INeRe INC subroutine to increment C 003/041 007 RET and then return ; routine to process the scores. This routine 003/042 024 012 RNoLOOP SUI 100 subtract 10 from negative of 003/044 030 INO low order, increment couht ; sorts the scores in descending order, adds the 003/045 104 062 003 JM.P ENDRNOT go to cnd test; ten lowest scores, subtracts ten times the 003/050 301 FRSTRND lAB fetch high order; 003/051 240 NoA clear flags; course rating, mUltiplies by 8.5) divides by 003/052 074 062 CPI 500 compare to decimal 50; 003/054 102 040 003 CFC tNeRC if = >50 then increment quotient 100, rounds off the result and displays the 003/057 302 LAC l ow order to A. 003/060 036 000 LOI 0 clear divide count in 0; handi cap. 003/062 240 ENORNOT NoA clear flags; 003/063 074 012 CPI 100 is it less than 1 0?; On Jan. 1, 1976, the multiplying factor 003/065 100 042 003 JFC RNoLOOP if not back for adjustment; 003/070 137 OUT 17 send A to units digit output; changes from 0.85 to 0.96. To adapt the 003/071 303 LAD fetch tens digit result; progra m, take the difference as obtained at 003/072 135 OUT 16 send 0 to tens digit output; 003/073 104 000 002 JMP DUFFER go back to consider next duffer; location 002/233, multiply by 4, add 50, *NOTE : The course rating in this example is assumed to be 69.5 . To account for divide by 100, subtract the quotient (disre· 10 double preci sion adds, this is multiplied by 10 giving 695. In octal, this gard the fraction) from the origin al takes two by tes with 002 in the high order, 267 in the low order. difference, add 5 and divide by 10. The *. NOTE: The mnemonic " BLK" is used to i ndicate that a block of memory quotient, dropping the fraction, will be the i 8 reserved for use by the program , with the name (SCORE here) used to reference the first address in the block. rounded off handicap. _ 47 Microcomputer A new six-volume programmed learning course from Iasis tells VOL V ASSEMBLERS AND you EVERYTHING about what PROTOTYPING SYSTEMS microcomputers are and how 'I/O\. \'II OCO\A~u"t~l' you can design and implement a "t\'\~ e -~\"t 'IA\C~ microprocessor-based system. Since the transistor was invented, no single electronics innovation has made such an impact as the micro computer. Powered by tiny semiconductor chips containing computing elements with the same powers and functions previously found only in large scale digital computers, these dedicated microcomputer systems are now being applied to literally thousands of applications. Microcomputers are automating assembly lines, providing the heart of sophis ticated electronic games, making " intelligent" computer peripherals even smarter, and are going so far as streamlining the operations of the fastest food chains. This revolution is occuring because micro- computers are very inexpensive-costing as little as $30 in production volume-easy to implement into a system, and significantly reduce the time and cost of product development. But there has been one serious drawback to this exp loding industry: Training materials and courses in the basics of microcomputer technology have been virtually non-existent, and the various published manuals and texts have been undecipherable to those not already intimately familiar with ultra-sophisticated logic design. Once a designer has the hang of it, microcomputer design is a snap. But without the fundamentals-never before available in such a readable, understandable and simplified format - microcomputer design has been unbelievably difficult. The comprehensive, step-by-step six volume Programmed Learning Course on Microcomputers from lasis Iasis Texts: 1. Binary Arithmetic makes the unbelievably difficult almost ridiculously simple. The authors of 2. Microcomputer Architecture these texts have been involved on a professional level in the micro 3. The 4-Bit Microcomputer computer industry since it became an industry. Their direct, first-hand 4. The 8-Bit Microcomputer 5. Assemblers and Prototyping experience in the whys, hows, wherefores and potentials of microcomputers Systems 6. 8-Bit Assemblers and Compilers Finally, you can get a comprehensive training course on microcomputers that puts all the hard-to-get information at your fingertips in an easy-to-read, easy-to-understand and even easier-to-implement manner. 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Specific details are provided on four of the indus The lasis course gives you more than 700 pages of detailed, illustrated microcomputer information-including more try's most versatile microcomputers-the 4004, 4040, than 1,700 self-tests you use to evaluate your progress 8008 and 8080 from Intel Corporation-but the basic plus programming and design aids that make the design of design information will apply to any and all micro practical systems very, very easy for you. processors. The si x volumes you receive with the course are: 1) BINARY ARITHMETIC ; 2) MICROCOMPUTER ARCHITECTURE ; 3) THE 4-BIT MICROCOMPUTER; 4) THE 8-BIT MICROCOMPUTER; 5) ASSEMBLERS AND PROTOTYPING SYSTEMS; and 6) 8-BIT ASSEMBLERS AND COM 88 PILERS. Plu s, this detailed course provides you with two programming pads and two simplified design aids so you may quickly and easily develop both 4-bit and 8-bit microcomputer systems. Use the coupon below to order your course from lasis, Inc., 110 First St. , Suite B Los Altos, California 94022 Special introductory price on this remarkable new course is just $99.50 ... and if it isn't everything we say it is or even more, return it within 15 days for a full refund! "I,t· l ~ ", I ,',!; .:: ':",,\":;,1 ,&;', ; " ' t .~':t. 91 ,,", ",' ,''';:'" ~:'::.,~ ,,' :~"j ",:,!~~';" ' ~I~ ~ ,,, <"" •.:: ,~ ~,",~ . , ':~ \~'':: ;':.~ ~ . ii~~ ~ ______• _ -,=--= Order before Nov. 30, and you'll save a full $25 on the Programmed Learning Course I ~1~ on Microcomputers! In addition, all introductory orders will include a bonus seventh I _ volume, the Microcomputer Applications Handbook! I (After Nov. 30, 1975 price for the complete las is course wi ll be $ 124.50, plus $2.50 for postage and handling.) I I Here's my check or money orde r (no cash, please). RUSH my You can use your BankAmericard or Master Charge, too! I 6-volume Programm ed Lea rning Course on Microcomputers, including the bonus Appl ications Handbook and programming 0 CHARGE MY ORDER TO THE CREDIT CARD NO . BELOW: I I aids, to the add ress below. HURRY! BankAmerica rd No . I 0 Send one complete cou rse for $99.50 in U. S. funds. My Master Charge No. I payment is attached. (California residents, pl ease add For Master Charge, add 4-digit number imme- I $5.97 State sa les tax.) diately above you r nam'e on the ca rd . It is I HERE 'S MY SIGNATURE ______0 Send me information by return mail on quantity discounts. (Sign here if credit card charge) I I Crod it ca rd ex piration date______ALLOW 15 DAYS FOR DELIVERY IN THE U. S. AND 6 WEEKS I I FOR DELIVERY OUTSIDE THE UNITED STATE S. NAME ADDR ESS I I Mail 10day 10: lasis, ORGANIZATI ON MAI L STOP ____ 110 First St. Suite B CITYI STATE I ZI P ______I I Los Altos, California 94022 ~--~------~ An Intel 8080 Op Code Table Fred Dittrich Fred Dittrich, 312 N 8 St (no 2), 31 1F 037 RAR 312 N 8 St (no 2) Columbia MO 65201, supplies this table of 32 20 040 Unimplemented 33 Columbia MO 65201 op codes for the 8080 instruction set. The 21 041 LXI H< LO> 50 102 66 146 MOV H,M 179 B3 263 ORA E 103 67 147 MOV H,ACC 180 B4 264 ORA H 104 68 150 MOV L,B 181 B5 265 ORA L 105 69 151 MOV L,C 182 B6 266 ORA M 106 6A 152 MOV L,D 183 B7 267 ORA ACC 107 6B 153 MOV L, E 184 B8 210 CMP B 108 6C 154 MOV L,H 185 B9 27 1 CMP C 109 6D 155 MOV L, L 186 BA 272 CMP D 110 6E 156 MOV L,M 187 BB 273 CMP E 111 6F 157 MOV L, ACC 188 BC 274 CMP H 112 70 160 MOV M, B 189 BD 275 CMP L 113 71 161 MOV M,C 190 BE 276 CMP M 114 72 162 MOV M,D 191 BF 277 CMP ACe; 115 73 163 MOV M, E 192 CO 300 RNZ 116 74 164 MOV M,H 193 Cl 301 POP B 117 75 165 MOV M, L 194 C2 302 )NZ < LO> 51 There's More to Blinking lights Than Meets The Eye Carl Helmers A blinking light peripheral is an inexpen dance and gyrate in interesting patterns has sive, entertaining addition to your computer remained. system. The use of multiple indicator lamps As a simple example of moving lights, under computer control to produce moving consider a single 8 bit byte of memory in patterns can lead to many hours of creative your computer, which might be called programming and pleasant amusement. BLINK. Assume that you have also con Playing with blinking lights is nothing structed an 8 bit output data latch which new to people working with computers. drives eight LEOs as shown in figure 1. When Early systems, to say nothing of science a certain program is started, BLINK might fiction movie caricatures, tended to have be initialized as follows : monstrous front panels with row after row o 0 0 0 1 000 of indicator lamps. These lamps were used to reveal various machine states. As computers Suppose this value is sent to the display, became more sophisticated, the need for which is set up so that a 1 bit li ghts an LED, many of these indicators diminished, but the then the display will look like this : fascination of making the indicator lamps • • • • 0 • • • OUTPUT WRITE - FOR THIS LATCH 7475'S +5V .PIN5 +5V GND-PIN 12 I I LED (a) 2 I 220n (B) A QA 1 ~ 3 14 'CI ~ B QB 6 II tC;( 'CI C QC 7 a 'CI Q( a 0 QD -- ~ \CY 7475 T 4 13 BUS RECEIVERS QUAD LATCH I (USE TYPICAL ICS I OF YOUR COMPUTER I COMPUTER SYSTEM) I DATA BUS K. JL I 4 I I 4 13 I I 2 I tQ{ A QA 3 14 \CY B QB d 6 II d~ C QC 7 a 0 QD J.. .~ ta1 ~ 'CI 7475 i I I QUAD LATCH ~ TO OTHER OUTPUT LATCHES Figure 1: The basic "straightforward" approach to display lamps. One latch is assigned to each of several output ports of the computer. The output port decoding logic will determine when the latch is addressed for output. The result of decoding is a WRITE signal which latches the data presented at the bus receivers. The sample program of figure 2 assumes two such display registers. In principle the idea can be extended to many registers in groups of eight, limited only by the computer's input output addressing capability and the available power for lighting LEDs. In this circuit, TTL fanout limitations on the bus receivers would limit expansion to a total of 10 latches. The LEDs can be mounted on a separate display panel with connections by means of dual in line header plugs and sockets. A neutral tinted glass or plastic cover plate and an attractive wooden frame are good finishing touches for the visible portion of the project. 52 Figure 2: The CATERPILLAR program listing. Opcodes and addresses are specified in octal notation for the BOOB CPU. Comments at the right are designed to help convert the program to other machines. address octal code label op. operand commentary 010/000 250 START XRA c lear carry and A; 010/001 036 377 LDI 11111111B first caterpillar word; 010/003 046 000 LEI OOOOOOOOB second caterpillar word; 010/005 304 MARCH LAE right byte to A; 010/ 006 022 RAL shift left into carry; 010/007 340 LEA then saved for next time; 010/010 303 LAD left byte to A; 010/011 022 RAL shift left into carry; 010/012 330 LDA then saved for next time; * note that RAL shifts old carry into A each time, * thus the above accomplishes shift from E's high * order bit into D's low order bit via carry ... ; 010/013 177 OUT 37 write into left lamps; 010/ 014 304 LAE fetch right value; 010/015 175 OUT 36 write into right lamps; 010/016 026 300 LCI 192D set delay loop constant; 010/020 307 DELAY LAM use 010/021 307 LAM several 010/022 307 LAM longish 010/023 307 LAM instruc tions 010/024 307 LAM to 010/025 307 LAM s t ret c h 010/026 307 LAM o ut 010/027 307 LAM the 010/030 307 LM-I l oop 010/031 307 LAM (a BYTE in time saves nine) ; 010/032 021 DCC decrement delay count; 010/033 110 020 010 JFZ DELAY if non zer o then repeat delay; 010/036 104 005 010 JMP MARCH back for another step; * note that during the operations at addresses 010/013 * to 010/036 the carry bit value set by the last RAL * is retained unchanged , so that the RAL at 010/006 * will shift the old high order bit of the l e ft register * (D) into the low order bit of the right register (E); This program uses only the internal CPU registers for its data, and assumes that 8008 output ports 36 and n are assigned to latched 8 bit displays so that a visible pattern can be seen. The key element in creating an illusion of With a program executing these four motion is time. If the program starts out steps, the pattern of lit indicators will be with data as shown above, waits a short seen moving to the left, disappearing on the time, then executes a left rotate instruction, left in the same step at which it reappears on a new pattern will be obtained. The new the right. By changing the program delay binary value 0001 0000 can be sent to the (step 3), the speed of the pattern's apparent display : motion can be changed. • • • 0 • • • • Figure 1 shows two quad latches which In the simplest of all motion programs, are used to drive 8 indicator lamps. The 220 these three steps are repeated in an endless o resistors are typical values for LEOs as loop: indicators. This value allows reasonable 1. Rotate BLINK left one bit position. brightness with most LEOs. The comple 2. Send BLINK to the display. ment outputs of the 7475 ICs used as latches 3. Wait n milliseconds. produce a lit LEO for each 1 bit received. 4. Go to step 1. When you purchase LEOs for a blinking light 53 B • • • 0 • • 0 • E • 0 • 0 • • • • 0 • 0 0 0 • • • • 0 • • 0 • 0 • A • 0 0 • 0 0 0 0 • 0 • • • • • • • • • • • • 0 • • 0 • • • 0 0 • • • • • • • • • • • • • • • • C • • • • • • • • • D • • • • 0 0 • • • • • • • • • 0 • • • • • • • • • • • • • • 0 • 0 • 0 • • • • 0 0 • e:•••• • 0 • 0 • • 0 0 • 0 • • • 0 • • • 0 • • • • Figure 3: Creativity in the arrangement of the lamps of your blinking light peripheral can make th e show more impressive and interesting. A : The traditional blinking light display, a la control panel, is a straight line of sixteen lamps in a row using two output latches. B: Tradition is nice, but how about a bit of circular thinking, using thirty two lamps in a circle with four output latches. C: Don't rule out the bouncing ball effect either. Here we make a parabola shape using sixteen lamps, one at the focus, with two output latches. D: With enough lamps, we can make a spiral show with one or more arms. Here 'are forty lamps using five output latches. E : There are an infinite number of patterns to be made. In this case, infinity consists of sixty four lamps using 8 output latches. . display, make sure they are all the same, as The cost of two 7475s, eight resistors, and the display will not look as attractive if eight LEOs is about $3 (using BYTE 's lamps of different types are mixed. advertising pages as a source of prices). Thus Now, suppose you use four latches for 16 a very reasonable display of 64 LEOs will set bits of data and 16 LEO s. How do you you back onl y $24 and the time it takes to program an 8 bit computer to do the shifting put it together. li ght pattern function for 16 bits? The bas ic Using a bit of imagination, the extension way in which this is accomplished is to shift of the program can lead to interesting the bits through the carry flag of your patterns running around non-linear configur machine. ations such as those illustrated in figure 3. Figure 2 il lu strates a program which does Variations in the patterns resu lt in displays a 16 bit sh ift in an 8008 microcomputer, of light. Beyond the scope of this short and sends the data to the output ports article are more complicated programs using reached by the OUT36 and OUT37 instruc the same displ ay peripheral : Programs in tions (octal 175 and 177, respectively). The which the light patterns do more interesting result is a moving display of 16 li ghts. A thin gs than simpl y chasing aroun d the race band of several bits is always marching rig ht track at uniform speeds. to left around the display at a steady rate. Try building a simple 16 bit blinking light But, why let the imagination end at a displ ay version first, then go on to bigger mere 16 bit display? The use of 10 ports can and better things. Then see if you don't be extended without too much cost (giv en agree that there's more to BLINKing lights limitations on power supp li es, of course). than meets the eye! • 54 Christmas Time Payment Plan Altair Manuals Altair 8800 Operators. . $ 7.50 lK Altair for Just $68 a Month! Altair 8800 Assembly...... $ 9.00 You can be the owner of an Altair 8800 with a 1.024 Altair 8800 Theory, Schematics...... $10.00 word memory module for just $68 a month. Each month Altair 680 Operators...... $ 7.50 Altair 680 Assembly. . . $ 7.50 (for 8 months) you send in your payment and we send Altair 680 Theory. Schematics . . . $10.00 you part of an Altair kit until you have the complete BASIC Language Documentation ...... $10.00 system. The advantages of the plan are NO interest or Assembler, Monitor, Edit or . . $ 7.50 fin ancin g charge, GUARANTEED price based o n today's 8800 4K Memory (includes Assembly, Theory & Schematics). $ 5.00 price, and free, immediate membership to the Altair Users 8800 2K Memory . . . $ 5.00 8800 11{ Memory $ 5.00 Group includi ng subscripti on to Computer Notes. 8800 SIOA ...... $ 5.00 Our terms are cash with order, BankAme ri card , or Master 8800 SlOB . . ... $ 5.00 Charge. If you send in an early payment we wi ll make 8800 SlOe...... $ 5.00 an early shi pment. By the same token, a late payment 8800 PIO ...... $ 5.00 8800 ACR ...... $ 5.00 will result in a late shipment. (After 60 days past due, COMTER II Operators . $ 6.50 the balance of the deal is cancell ed. All payments must COMTER II Assembly .. $10.00 be made within 10 months ). COMTER II Theory, S chematics...... $10.00 Total $544.00 (Retail price: Alta ir 8800 $439.00. Memory VLCT (Assembly, Operators. Theory) . . . $ 5.00 $97.00. Postage a nd Ha ndling $8.00- Altair Lin e Printer Interface . . .. $ 5.00 totill $544.00) Documentation Special One Altair Users Group Special Altair 8800 Operators. Assembly and TheolY manuals plus BASIC Each mon th th e Altair Users Group sponsors a software contest and Language manuil l (regu larly $3650). NolV just $15.0.0. each month MITS gives away $130 in credit to the winners of th is contest. At the end of th e year. th e aut hor of the overall best program Documentation Special Two will receive $1000 in credit. Alta ir 680 Operators. Assembly and TheolY manuals. Regularly $25. Membership to the Altair Users Group (the largest of its kind in the NolV just $14.50.. world) is free to Altair 8800 owners. However. even if you don't own an Altair. YOLI can be an associate member JOI' one year at th e special low price oj $10 (regu larly $30.). Documentation Special Three As a member of the Alta ir Users Group. you will be kept informed of B/\SIC Language manual. Package I (Assembler. Monitor. Editor). and Alt air developments. software contests. and general computer news BASIC language beginne rs text (My Computer Likes Me When I Speak through th e monthly publication. Computer Notes. You \vill have access BASIC by Bob Albrecht). Regularly $1950. NolV just $12.50. to th e Altair Software Library and you can communicate to other Alta ir users throughout the world. MITS/ 6328 Linn NE/ Albuquerque, NM 87108 Note: These specials expire on J a nu ary 30, 1976. 505-265-7553 or 262-1951 Mail this special Altair Coupon Today! o Enclosed is check for $ 0 BankAmericard # 0 or Master Charge # _____ o Altair 88000 Kit 0 Assembled 0 Fan 0 Christmas Time Plan 0 Expander Board o Altair 6800 Kit 0 Assembled 0 Fa n 0 I/ O Sockets o Teletype 0 Line Printer 0 Comter II 0 VLCT 0 Disk 0 Disk Drive Only 0 Disk Controller Only o Memory Module 0 I/O Module ( 11< 1 on <" 1'",..11,· ,h.·\·t) Postage & Handling: Add $8 for Altair 8800 or Altair freight. Warranty: 90 days on parts .for kits and 90 680 and $3 for any cards or peripherals if ordered days on parts and labor f()r assembled units. PriCes, separately. Teletype and Line Printer shipped by collect specifications, and delivery subject to change. o Documentation Special One 0 Documentation Special Two D Documentation Special Three o Altair Users Group plus Computer Notes o Please put me on your mailing list SHIP TO: BILL TO: NAME. ______NAME ______ADD RES S ______ADDRESS ______CITY CITY ______STATE & ZIP______-=-- __~ ______STATE & ZIP______o Please send Christmas Card to above address COMPANY (IF APPLICABLE) ______announcing gift and anticipated delivery; MITS/ 6328 Linn NE/ Albuquerque, NM 87108 505-265-7553 or 262-1951 Photographic Notes on Wire Wrapping Carl Helmers Photo 1: One of the most widely used Photo 2: The business end of an industrial custom assembly methods in the computer quality wire wrap tool is the bit and sleeve industry is wire wrapping. Special square assembly. The bit is driven by a high speed wire wrap posts are built into sockets or motor (or hand operated mechanism) and mounted directly onto components. The rotates around the post to be wrapped. The stripped ends of insulated wires are con center of the bit has an alignment hole nected to the posts using a special electric or which fits over the wire wrap post to guide hand operated tool. The result is an the operation. The bit also has a groove excellent connection with gas tight "vacuum along its length into which the stripped end welds" at each corner of the post as the of a wire is inserted as shown. The wire is sharp edge cuts slightly into the wire. Wire held in the groove by the sleeve and is pulled wrapping is a quick, easy and permanent out during the process of wrapping. The way to connect point A to point B in your sleeve itself does not rotate and is held custom circuitry. rigidly in position. 56 Photo 3: The bit and sleeve may be removed from the typical industrial wrapping too1. The groove for the wire can be seen as a line running the length of the bit in this photo graph . Note how the groove has an enlarged section near the tip of the bit. This enlarged section allows a small length of unstripped wire to be inserted so that one turn of insulation will be wrapped around the post. Photo 5: To quote the previous caption, " When the trigger has been pulled on a loaded wire wrap gun, the result (hopefully) will be a perfect wrap every time." Here is an example where hope was in vain. A problem which sometimes occurs is the "wrat's nest" wrap shown in this photo graph. The normal operation of the wrapping gun includes retraction of the bit inside the sleeve as the wire layers are added to the coil around the post. A spring loaded mechanism in the gun provides for this controlled retraction. Occasionally the bit sticks and does not retract properly. This results in a jumbled mess as layers of wire wrap over previously wrapped layers. If the wrat's nest wrap occurs only occasionally, the likely cause is your tool position while wrapping. If the bit is not centered about the wrapping post, friction in the pilot hole Photo 4: When the trigger has been pulled can prevent the bit from retracting properly. on a loaded wire wrap gun, the result If the wrat's nest wrap occurs consistently a (hopefully) will be a perfect wrap every likely cause is dirt and grime buildup on the time. The wrapping action begins at the bit. If particles of metal scraped off the wire bottom with a single turn of insulated wire are allowed to accumulate, the resultmg followed by successive layers of stripped friction can inhibit retraction of the bit. wire. In this picture you can count 15 layers Thus if the gun consistently makes wrat's of bare wire on the side facing the camera. nest wraps, removing the bit and cleaning it The single turn of insulated wire is produced may resolve the problem. After cleaning, the by what is called a modified wrap bit. This bit may be oiled. Oiling should be done very single turn around the post uses the insula sparingly at the gun end of the bit so that tion to help act as a strain relief to prevent excess oil does not get in the groove and breakage when handling wires while onto the wire. When a wrat's nest occurs, debugging a system. A standard wrap bit whatever the cause, good practice indicates would start the first coil of bare wire minus that you should remove the mess and start the strain relief feature. over. 57 Photo 6: Continuing on the theme of less Photo 7: The length of the coil produced by than optimal wrapping results, this picture the wrapping action is a function of the shows an example of the "impatient wrap." length of bare wire prepared for insertion in The primary cause of the impatient wrap is the tool. For the typical .025 inch square your own impatience to see the result. If the wrapping posts with 30 gauge wire, approxi wire wrap gun is removed from the post mately 8 layers will be added to the coil for while the wrapping action is under way, the each inch of bare wire inserted into the bit. result will be widely spaced coils of wire This photo shows an example of the "pigmy often covering the length of the post. This wrap." When a short coil of wire is pro example is an exaggerated version concocted duced, one possible explanation is that not on purpose; the typical case is a normal base enough wire was stripped when preparing for to the coil with the top one or two layers the connection. (Another possible explana spread out. The solution to this problem is tion is that the wire broke, leaving most of to allow the gun to do its work before the stripped section inside the groove where removing it from the post. In a case such as it must be removed by disassembling the the one shown here, removal of the connec· tool.) tion and rewrapping should be done. In milder forms of the impatient wrap, the wrap would not necessarily have to be replaced. 58 Photo 8: It is often necessary to connect second post from the right, you must first several wire wrap posts to one electrical bus. remove the second level wrap on that post. The method of accomplishing this is to However, the wire to the second level comes create a chain of point to point wraps. In from the first level wrap of the third post such a chain each wrapping post except the and must be removed at both ends since wire first and the last will receive two wraps: a wrap wire cannot be recycled. But this level one wrap at the bottom and a level two presents the same problem all over again at wrap above it. One way to build the chain is the third post, and the problem will propa to start at one end connecting one post to gate down the chain until all the wire has the next until the last connection is reached. been removed. One way to get around the In the model shown here, wrapping began at problem simply is to clip the removed wire the right and progressed toward the left. and leave a dummy wrap on the post, There is a major disadvantage with this making any new connection at the third technique of chaining. Suppose you want to level if the post is long enough. There is an remove the link between the two posts alternative method of connection shown in furthest to the right in the photo. Note that the next photograph which minimizes the in order to remove the first level wrap on the effects of a chain change on long chains. Photo 9: The alternative method of chaining with an even number of posts, this will put a which minimizes propagation of changes is level one wrap at every post; for buses with illustrated in this photograph. This technique an odd number of posts, one post will be left is highly recommended for initial wiring without a connection after all the pairs are of any bus which connects more than 4 wired. Then, each end of each pair is posts. The principle which governs this form connected to its neighboring pair with a level of wiring is simple: Wires are connected to two wrap, completing the chain. For odd the same wrap level at each end. If a change length buses, the solitary unwrapped post is is required at level two, only one wire has to connected to one of the pairs at this stage. be removed to break a link. If a change is This method of wrapping works only with required at a level one link, three wires must the initial wiring of a chain. If later changes be removed (and two possibly rewired). are made, such as adding or deleting seg When wiring a bus this way, the first step is ments in the middle, necessity may force a to connect all the possible pairs of posts in hybrid version of the two techniques of the bus with wraps at level one. For buses chaining. 59 Taking Advantage of Memory Address Space James Luscher The address space of a computer is the set main memory addressing. Thus there are 2012 Jefferson Street of addressable data locations provided in several distinct address spaces associated Madison WI53711 the design of its instruction set. A common with the 8008 design. misconception is to view a computer's The designers of a computer have to give address space as the equivalent of the actual careful consideration to all the address memory that the machine has. This point of spaces supported by the computer they view is both incorrect and too restrictive for create. The input instruction address space the hobbyist or engineer who is able to allows up to 8 locations as input ports. If the modify his machine. designer of the Intel 8008 had wanted to allow 16 input devices he would have needed Thinking in terms of address spaces is 4 bits. Using the larger address space means more productive than thinking in terms of that some instructions must be modified, memory for three reasons : First memory is eliminated or restricted because the bit normally installed in blocks of addresses retained for addressing cannot be used to where each word is identical in length, speed distinguish instructions. of access, etc. In contrast, an address space You pay for the 'extra address space in need not have identical physical impl ementa your computer even if you don't use it fully. tions at each location. Second there are You pay for 8 input ports even if you only often several logically distinct address spaces need 2 input addresses, and the cost is in in a computer while there is usually only one terms of the instructions which could not be main memory for programs and data. implemented, You also pay in terms of the MUltiple address spaces have separate func bits of memory which are required to hold tions or functionally distinct address spaces the unused parts of the addresses. Deciding (e .g., input output device space and main how to handle the addressing of various memory address space) can be mel·ged. functional elements in a computer is one of Lastly, a computer normally has a smaller the most crucial issues in the design of an main memory than it is capable of instruction set. addressing, thus wasting some (or most) of the address space. Non·Uniform Address Spaces To see that an address space need not A computer's address Non-Memory Address Spaces identify uniform arrays like main memory space is not necessarily As an example of a non-memory address let's re-examine the 8008's ADr instruction, equivalent to the amount space, let's first consider the ADr instruction The register address space can specify one of of memory it has installed. (add register to accumulator) as imple 8 locations with 3 bits. However there are mented on Intel's 8008 microcomputer chip. only 7 registers in the 8008. Each of the Its bit pattern is 10000RRR, where RRR registers numbered 0 to 6 specifies a byte of represents the register address field. This data which is part of the 8008 CPU. These defines an address space for the 8008 CPU registers, named A, B, C, 0, E, Hand L, are which is not directly associated with main the seven "normal memory" addresses in the memory at all. As a second example, con 8008 register address space. Each of these sider the 8008 input instruction, INP. The registers, if selected by the RRR bits of the bit pattern for this instruction is ADr instruction can have its content added 0100MMM1 where MMM is the input unit to the A register when the instruction is address field. This defines a second address executed. The eighth address in this address space for the 8008 which is also unrelated to space (numbered 7) is different in function 60 from the other seven. Address seven in the state of the bit in memory. In either of these register address space is not a register at a ll. first two ways, the unused bits may be wired Referencing register 7 causes the H and L to logical zero or one. A third way, shown in registers to be placed end to end forming a figure 2d, is to connect the ou tpu t of the 16 bit address register. This is t hen used to single bit memory to a ll 8 data lines at the address a byte in main memory. T hu s one interface to the bus. When this method is element of the register address space of the chosen, the data valu e loaded from the 8008 is very different from the other seven one-bit memory locations wil l be either zero elements (see figure 1). or -1 (hexadecimal 00 or FF). The one bit wide memory is much less expensive si nce Using Non-Uniform Main Memory Address only the single bit being used at any address Space has a physical implementation as a memory The previous example illustrated a non device. uniform address space bui lt into the archi tecture of a specific computer chip, the 8008'5 ADR INSTRUCTIONS 8008. There is no reason why t he hobbyist 1 I can't use the same concept of a no n-un iform 10 000 RRR' address space element to hi s advantage in the ~ I Designers of computer INSTRUCTION REGISTER design of custom systems or additions to IDENTIFIER ADDRESS architectures have to give SPACE existing systems. Suppose that someone has RRR REGISTERS careful consideration to all a 6800 processor wi th 4096 bytes of 000 CD the address space memory and wants to implement t he LI FE 001 crJ supported by the com appli cation on this machine. With a 64 x 64 0 10 c:o puter they create. grid, 4096 bytes of memory alone would be 011 C[:J req uired for data storage if one byte is used l 100 CD for each element of the LI FE matrix. Two 101 [JD normal solutions to the problem are to buy 110 more memory or to impl ement subroutines CD III which store 8 matrix elements into each byte, thus requiring only 512 bytes for data cr I H I L plus storage for the packing and unpacking subroutines. This last approach has the unfortunate drawback of being slow, not to mention its added programming difficulty. There is another clever way to solve the Figure 1: An example of a small non-uniform problem of accessi ng large arrays of bits, a address space is provided by the register address space of an 8008 microprocessor. Seven out of way which is open to the hobbyist who eigh t possible locations are registers of the pro designs his own machine or doesn't mind cessor; the eighth (M) however has a very special addi ng to his machine. It is possible to build hardware meaning and is not implemented on the a 4096 bit memory at a cost much lower chip at all. than the cost of a fu ll 4096 byte memory A 6800 system which uses only 4096 board. In effect you are rep lacing t he memory addresses is not using 94 percent of packing and unpacking routines with the its total ava il able address space of 65536 chip address se lection hardware at a nominal possible locations. There is plenty of space dollar cost and a great increase in speed. for another 4096 sin gle bit memory. This Figure 2a illustrates the concept of t he 4096 approach is cost effective, speed effective bit memory added to a system wh ich al ready and makes better use of the hardware has 4096 bytes of random access memory. resources inherent in the CPU chip design. It Since only one bit of information is is a good solution to the problem of storing involved, the way the addressed bit is an array of bits and can be used in any hooked up to the bus interface data lin es is a system which does not require byte memory matter of personal preference and program or peripherals at every avai lable location in ming convenience. One way (figure 2b) is to address space. connect the single active bit to the low order bus line at the bus interface. Testing the 10 and Other Uses of Address Space state of t he stored bit could then be done by In the article "Notes on Parallel Output loading from the memory location of the bit In terfaces" in BYTE #3 (page 52), Carl and testing the zero flag with a conditional Helmers pointed out how memory address branch instruction for the computer being space can be used to address output devices. used. A second way is to connect the active In such a usage, the 10 address space and the memory chip to the high order bit, in which memory address space of a more conve n case the sign of the resul t (in two's comple tional design are one a nd the same thi ng. ment notation) corresponds to the present This is the only way 10 is done in the DEC 61 Figure 2: For purposes of manipulating arrays of 64K AVAILABLE single bit data, it is possible to use otherwise empty ADDRESS BK --, memory address space for a partial implementation Don't make the mistake of SPACE I I 4K X I of read·write memory. a. i11ustrates the memory th inking you have to I INSTALLED BIT : MEMORY al1ocations with such a partial array in a typical include every bit of every I example. b., c. and d. show three alternative word in a memory. connections of the partial word 's data to the bus 4K X B interface. Leaving out one or more INSTALLED BIT MEMORY memory chips will not in general affect the function of the remaining portions TO I BIT TO I BIT TO I BIT of the memory module. ARRAY ARRAY ARRAY LOGICAL 0 FROM LOGICAL 0 OUT '·MEMORY·' IGNORED IGNORE INPUT WRITING TO "MEMORY" LOW ORDER BIT IS SOU RCE FOR ~ WRITE SYSTEM SYSTEM SYSTEM IBUS IBUS IBUS SOFTWARE SEES SOFTWARE SEES SOFTWARE SEES o OR I o OR -128 o OR-I (HIGH ORDER BITS (SIGN BIT , BIT7, (DATA TO CPU REPEATED IGNORED) IS THE DATA 81T) IN ALL 8 BITS) PDP-11 family of minicomputers, as well as the result into Y cou ld be impl emented microcomputers like the 6800 and the 6501 fairly simply: family . These mac hines have no 10 in struc tions at all. In the PDP-11 family, there is LDX X fetch first operand (16 bits); one particul ar 4096 word block of memory STX A16 store into 16 bit A reg ister; LD X Y fetc h second operand (16 bits); address space reserved for use wi th external STX B16 store into 16 bit B register; dev ices; for most microcomputers, specific LDAA #$01 define control code allocations of 10 addresses in memory STAA ( 16 and store it into extern al unit; address space are a discretionary choice of LDX A16 fetch accumu lated result; the system designer. STX Y and store it into Y; Th e addressing concepts used to interface arbitrary 10 devices can als o be used to add The add resses A16 and 816 refer to the new functions to your computer. Since a registers of the external math unit built CPU cannot tell what kind of memory it is along the Iines of figu re 3; the control interacting with over the bus, it is possible to register C16 when set wi th an appropriate have memory locations which se rve special code will execute the math operation - computing purposes. Suppose that you want which could just as eas ily have been a to manipul ate 16 bit words with a 6800 multiply or a divide or so me other function system. Specially implemented address space such as block data move ment or an array locations can be used to store and man operation implemented in hardware. What ipulate data with the longer word length we have done here is to augment the data indepe nd ent of the CPU's restrictions. handling capabilities of the microprocessor Figure 3 shows two 16 bit registers and by addi ng hardware which interfaces one control register for a simple 16 bit through a series of locations in memory arithmetic uni t. Registers A 16 and 816 address space. With this type of har dware occupy two memory address space locations addition, the onl y programming required is eac h, for a total of four locations. The thus a series of loads and stores needed to control register occupies one address loca move the data to and from the special tion. Now su ppose that locations X and X+1 memory locati ons, thus saving a lot of on the main memory section of the com microprocessor programming and making puter contain a 16 bit number, and that extended precision arithm etic much faster locations Y and Y+1 contai n a second 16 bit than the eq ui va lent software version. Wh ile number. A routine to add X to Y and store the ci rcuitry to perform such extend ed 62 DIGITAL DATA RECQRDER for SYSTEM Computer or Teletype Use DATA 6US INTERFACE Up to 2400 Baud $149.95 LOCATION AI6 LOCATION AI6 + I r+ ! ~ LOCATION 616 A DATA A DATA I SWITCH I SWITCH SELECT LOCATION 616+ I HIGH LOW ! A HIGH A LOW WRITE I 6 HIGH LOW I I CONTROL I 6 Uses the industry standard tape saturation method to beat all FSK LOCATION 616+1 systems ten to one. No modems or LOCATION 616 FSK decoders required. Loads 8K of memory in 34 seconds. This recorder LOCATION A16+1 enables you to back up your computer by loading and dumping programs and LOCATION AI6 data fast as you go, thus enabling you to get by with less memory. Great for ~ small business bookkeeping. ADDER ADDER IMAGINE! A year's books on one MRYIN HIGH LOW cassette. I Thousands are in use in colleges and I CARRY OUT r 1 businesses all over the country. This I new version is ideal for instructional, OPERATION L LOCATION CONTROL C amateur, hobby and small business CONTROL LOGIC CI6 use. Ideal for use by servicemen to load test programs. Comes complete A DATA SELECT SWITCH with prerecorded 8080 software program used to test the u nits as they A WRITE CONTROL J are produced. (Monitor) SP£CIFICA TlONS, Figure 3: Another use of memory address space resources is to interface special function A. Recording Mode: Tape SalurJ- F. Comparability: Will interface [iOIl binary. This is not an FSK any computer using a UART or hardware. This diagram shows the concept of a 16 bit arithmetic module which can be or Home type recorder. No voice PIA board. (Altair, Sphere, capability. No modem. M680D etc.) constructed and interfaced as four data locations and one control location in memory B. Two channels (1) Clock, (2) G. Other Data: 110 V - (50-60) address space. Data. Or, two data channels pro- Hz ; 2 Watts total; UL listed viding four (4) tracks on [lie #955D; three wire line cord; cassette. Can also be used for on/off switch; audio, meter and NRZ, Bi·Phase, etc. light operation monitors. C. Inputs: Two (2). Will accept Remote control of motor operations is not trivial, it is a lot less TTY, TTL or RS 232 digital. optional. Four (oat, seven can· D. Outputs: Two (2). Board ductor remoting cable provided. expensive and easier to accomplish than changeable (rom TTY, RS232 or H. Warrantee: 90 days. All units TTL digital. tested at 110 and 2400 baud building a complete CPU with instruction E. Erase: Erases while recording before shipment. Test cassette one trijck at a time. Record new with 8080 software program decodi ng, conditional bran chi ng, su brouti ne data on one track and preserve included. This cassette was three or record on two and recorded and played back during calling mechanisms, interrupts and all the preserve two. quality control. other capabi liti es needed in a processor. This ONE DOLLAR brings operating and main is the way to build an " extended ins truction tenance manual with schematics. set" in a machine which nominally does not COMING NEXT MONTH - IN KIT . . . the central theme is to have any extension possibilities . FORM always keep an open and Extended ar ithmetic hardware of this • Hexadecimal Keyboard - Load pro kind is very common on medium and large grams direct from keyboards' 16 creative outlook towards keys and verifying display. Does not utilizing all the capabilities scale machines where speed improvements use Computer I/O. are needed. For example in floating point your machine provides ... • I/O for use with Computer Aid or arithmetic which involves a lot of double other digital recorders. Variable precision addition and shifting, a common baud rate selectable on externally located unit by one knob. Can load commercial technique is to buy a fast computer or accept dumps without floating point pl·ocessor from an outside software. Turnkey Operation. For vendor and plug it into a minicomputer. This any 8 bit computer. type of extension of the central pl"Ocessor Reco rd /PI ay back Am pi ifi er. Expanded version of our Computer capabilities by doing computation and data Aid board for use with your own manipulation in the address space (ex ternal deck (cassette or reel to reel). Go to to the CPU proper) is something that the 9600 baud on reel to reel. Digital in, diQital out, serial format. advanced hobbyist may find to be a * Interested in these? Send your name challenging and useful addition to the and address for brochure when released. system. Whether adding instruction set Send check or money order for $149.95 extensions or implementing partial memory, plus $2.00 Shipping & Handling (N.J. Resi· dents add 5% Sales Tax) to: the central theme of this is to always keep an open and creative outlook towards NATIONAL multiplex utilizing all of the capabi lities YOUI· machine 3474 Rand Avenue, Box 2BB CORPORA nON provides - especial ly the address space. - South Plainfield, New Jersey 070BO 63 K or k? Manfred Peshka The lack of conventions and standards 15 for the decimal number fifteen. used to abbrevi ate un its of measure, to Leading zeros, on the other hand, are determine scale of measurements, base of important in the re presentation of strings. numbers, or mathematica l, relational, and Arithmetic operations req uire numbers, an d logical operators, may occasionall y lead to logic operations use strings. In the latter confusion and mi sunderstandi ngs. There are case, leadin g zeros are sign ificant. For peopl e who prefer to use such ex pressions as exa mpl e, a 16 bi t register is to be set to a KB for 1024 bytes, CPS for characters per value of 15. On e approach, using numbers, is second, LPM for lines per minute, etc., while to zero the register and add the hexadecim al others fo llow different conventions, such as number F to the register. Another approach, kHz for 1000 hertz, m/s 2 for meter per usin g strin gs, is to load the register with the squared second, MB for megabyte (either bit string '0000 0000 0000 1111 ' whic h can 1,000,000 or 1,048,576 bytes, depending be represented in hexadeci mal notation as upon convention), and so on. Some people '00 OF'. The spaces within the string quotes like to use AMPS, or Amps, or amp s, or A, are not part of the sy mbols representing the to denote the uni t to measure electri c strin g va lue; they simpl y add to the legibil ity current. We fi nd abbreviations vary ing and may be omitted. In the above example, dependin g upon scale; sec stands for second, the strings were qualified: Th e fi rst one is a while ms means milli second. Similar bit string, and the second one a hexadecim al problems may ari se from the use of numerals strin g. An unqualified string, therefore, is to indicate numbers: 11 may mean in binary assumed to be a text string consisti ng of the value three, in octal the va lue nine, in letters, digits, and punctuation marks dec imal the value eleve n, and in hexadecim al including spaces: ' , is a string of a s'mgle the value seventeen. Also relational, mathe space on your typewriter or terminal which matical, and logical operators are not con transl ates to '40' hexadeci mal or '01 00 sistently used. Some writers prefer to use the 0000' binary in the Extend ed Binary symbol AND, others the ampersa nd (&), and Dec im al Interchange Code (EBCDIC). others use the dot (0) to indi cate the logical In other words, numbers are decimal, and AND operation. You find the slas h (/) used strings, which are to be encl ose d in string for divi sion of numbers, or to mean the quotes, are the usu al letters, digits, and logical OR operation. special sy mbols, unl ess they are specifica ll y To help our reade rs understand the use of qualified as binary, octal, or hexadecimal these different symbols, BYTE will attempt representations. to consistently empl oy certai n ab breviations Ambi guity exists als o in the symbols k for frequently used units of measu re, sca le and K used as scale factors. Acco rdi ng to factors in measurements, operators, and Webster's New Collegiate Di ctionary (1975, number bases. page 629), the lower case letter k mea ns All numbers are ass umed to be decimal 1024; according to conventi onal use, such as numbers unl ess it has been stated specifica ll y kg for kilogram, km for kil ometer, etc., this to the contrary : In these in stances the base symbol mea ns 1000. In the co mpu tin g litera of the number syste m is indicated in the ture, on the other hand, the cap ita l letter K text, in a column headin g, etc. Leading zeros is often used in meas urin g memory size and are omitted. The hexadecim al number OF Iine transmissi on speeds. In these ins tances K will be written as F fo r the sa me reason that means a factor of 1024. BYTE will fo ll ow leading ze ros in dec imal numbers are thi s convention : K means 1024 and k is a omitted. We generally do not write 015 but factor of 1000. There are many more sca le 64 factors used in scaling measurements. Table 1 shows the various unit of measure prefixes which will be used in BYTE . All but one scale factor are powers of ten. The exception is K which equals 2**10 or TROUBLED BY 1024. Th e two as terisks have been empl oyed to indicate ex ponentiation instead of the frequently found superscript 210. The pur TRIGGERED pose of this notation is to facilitate the printing of fo rmulas on lin e printers and terminals which otherwise would require speci al hardware and programming to raise SCOPES? the exponent. In a similar mann er the slash (J) is bein g used to indicate di vision. Table 2 below lists operations performed on numbers. Table 1: Scale of Measurement Prefixes Abbreviation Meaning and Example T Tera or one tri II ion; five terabi ts or 5 Tb G Gi ga or one billion ; two gigahertz or 2 GH z M Mega or one million; 28 megabytes or 28 MB K K or 1024; two K bytes or 2 KB or 2048 B k Kil o or one thousand; two kilohertz or 2 kHz h Hecto or one hundred; 5 hectometers or 5 hm The Hickok Model 512 Dual D Deka or ten; six dekaliters or 6 DI Trace Oscilloscope eliminates d Deci or one tenth; fiv e decimeters or 5 dm c Centi or one hundredth; 90 centimeters or 90 cm the set-up and precision m Milli or one thousandth; one millihenry or 1 mH problems you've had to accept u Micro or one millionth; six microfarads or 6 uF using other triggered scopes. n Nano or one bi Ilionth ; 18 nanoseconds or 18 ns It's easy to set up p Pico or one trillionth; four picofarads or 4 pF • Simplified color-coded front panel controls. • Beam finder quickly locates off-scale Table 2: Mathematical Operations traces. • Foolproof triggering to 15 MHz. Abbr Meaning and Example It gives you superior performance x ( ) Function, where x is re placed by a function abbreviation, • 10 MHz response flat within 3dB. and th e arguments are placed in parentheses, e.g., Excellent pulse response. MAX(4, 7, 2) is 7, the maximum of the three va lues. • 3% accuracy on vertical and hori ** Exponentiation; 2**10 zontal ranger. Negation, a prefix operator; - - 4 is 4 Hickok industrial lab quality and con * Multiplication; A * 4 struction Di vision; 4/8 + Addition; A + C Glass epoxy PC boards used through Subtraction ; 5 - 4 out. Regulated power supply. 00 Table 3: Concatenation and Comparisons AT YOUR DISTRIBUTOR $675 complete with probes and accessories Abbreviation Meaning and Exampl e CAT or II Concatenation ; 'aC' CAT ' , yields 'aC ' HICKOK LT < Less th an; , , LT 'a' in EBCDIC NL -,< Not less than the value innovator LE <= Less than or equal to EO Equal to INSTRUMENTATION & CONTROLS DIVISION NE -, = Not equal to THE HICKOK ELECTRICAL INSTRUMENT co. 10514 Dupont Avenue. Cleveland. Ohio 44108 GE > = Greater than or equal to; if AGE B then ... (216) 541-8060 • TWX: 810-421-8286 GT > Greater than ; it is false that 5 GT 6 NG or -, > Not greater than ; 5 NG 6 is true 65 Table 4: Logical Operations and Assignment Abbreviation Meaning and Exampl e Besides mathematical operations which require numbers, relational operations (com NOT or -, Denial, a prefix operator; '0' is --, '1' is always true parisons) may be performed on either AND or & Conjunction; C := A & B numbers or strings; in addition, only strings NAND Negated conjunction may be concatenated, i.e ., tied together. The OR or Alternation D := C A string 'abc ' concatenated with '1234' results NOR Negated alternation in the string 'abc1234'. This may be written Assign ment; X:= 15 either 'abc' CAT '1234' or 'abc' II '1234'. Since not all terminals have these special symbols, an alternative set of two or three amps, AMP, Amp, Amps, AMPs, AMPS, upper case letters can be employed. The ampere, am peres, a or A to denote the unit abbreviations for relational and concatena of measure for electric current. Often abbre tion operations are shown in table 3. viations are not used consistently, e.g., sec Whil e the concatenation of two strings versus ms which stand for second and results in a string, a comparison operation mill isecond, respectively. returns a value of true or false which can be There also seems to be little consistency expressed as a bit. A binary '1' represents in spelling and hyphenating, e.g., Hertz or true (or yes) and '0' false (or no). This value hertz, Giga-Hertz, GigaHertz or gigahertz, of a comparison may be assigned to a logical etc. We decided, therefore, to spell units of (bit string) variable. In this context, the measure in lower case letters. After all, these differe nt uses of the equality symbol are measurement units and not the people become very clear: It is used to assign a after whom they were named. value to a variable, and to test eq uality. Th e inconsistent us age of abbreviations In order to make the difference between creates a real problem; it's like learning the assignment operation and the equality different languages, or dialects, to say the comparison more clear, we wi II use the colon least. We thought that frequently used units followed by an equal sign (: =) to denote the of meas ure should be abbrevi ated as short as assignment, and reserve the equal sign for possible, preferably as a single letter, unless comparisons of equality. To set a 16 bit this conflicts with stan dard usage . We will regi ster RA to a value of 15, you may wri te attempt to us e cap ital letters for abbrevia RA:=15; to compare the register with the tion s becaus e they stand out more clearly value 15, you may write RA=15. In this than lower case letters. instance the comparison happens to return a Acronyms, by the way, are always capital true value, i.e., a '1' bit which may be saved letters because each letter rep rese nts the first in a bit string variable named SWITCH by letter of each word of the compound term writing SWITCH :=RA=15. Of course, this for which the acrony m stands. Multiple latter expression does not mean that you letter abbreviati ons, on the other hand, may may type it into your computer and expect have an initi al capital letter followed by results. This depends on the availability of a lower case letters, such as Hz for hertz. compiler which would generate the appro Table 5 Iists some of the more frequently priate code. On the other hand, this state encountered units of measure in BYTE . • ment expresses an intent and a purpose of a computation, no matter how many machine instructions nee d to be issued, regardl ess of Table 5: Units of Measure Abbreviations the computer at hand. Like numbers, bit strings have their own Abbreviation Meaning and Example set of operations resulting in bit strings. Special graphics are often us ed to indicate A ampere; 5 kA, five ki loamperes these operations. For example, some peopl e b bit; 1 Kb, one K bits, K bits prefer the dot (0) to indicate logical AND, B byte; 14 KB, 14 K bytes others use the ampersand (&), and others use C character; 14.8 Cis, 14.8 characters a second alphabetic keywords like and or AND. We db decibel; 40 db, 40 deci bels will try to be consistent in our use of these g gram; 3 Dg, three dekagrams symbols in order to facilitate your reading of H henry ; 50 mH, 50 millihenry the magazine. Since only a few computer Hz hertz; 2 G Hz, two gigahertz output devices have extended graphic m meter; 10m, ten meters, ten meter ban d character sets, two choices are presented in o ohm; 28 kO, 28 kiloohms table 4. second; 1 ns, one nanosecond Abbreviations of units of measurement v volt; 16 mY, 16 millivolts vary widely. We find, for example, amp, W watt; 2 MW, two megawatts 66 The supply comes as a black box with several interconnection terminals. Two of these terminals are for the 110 V A( input. For The Joules, Three other terminals are for the positive output, negative output, and ground. For +5 Volt TTL then, the negative output should It's a Steal be connected to ground. Since it is a black box, the supply does not come with line cord, pilot light or switch. I surmounted this problem by building the supply into an I just bought a 105 W power supply for Peter H . Helmers aluminum chassis along with a custom ±12 V under fifty cents a Watt. This is the 79 Evangeline St. power supply. Although the unit is built "sophisticated logic supply,"* 21 A at 5 V Rochester NY 14619 with massive heat sinks, I decided to mount which is available from at least two sources: a ventilating fan to ensure good air flow for Meshna Electronics, P.O. Box 62, E Lynn an extra measure of cooling. MA 01904 and Electro Science Mart, 119 The power supply comes with a fuse Foster St., Peabody MA 01960. Using stan protected output and a voltage adjustment dard TTL logic, a good rule of thumb is to pot. The pot adjusts the output from 4 V to allow one A at 5 V for approximately 30 I(s. Thus this power supply, manufactured about 5.6 V. I also hooked up a test load of by Dressen-Barnes, is capable of powering a % 0, 50 W resistor to check on the ripple approximately 600 I(s. For the average of the supply with a 10 A load. I could see only about 10 to 15 mV of ripple on my computer hobbyist who is designing his or oscilloscope. Also, voltage stability over a her own system, one of these supplies will be period of 24 hours was good; I saw no perfect for the main power supply. It is cheap enough to buy right away, and it has measurable drift. In summary, this supply has the capacity sufficient capacity for just about any con to rectify a lot of current problems. Watt a ceivable future expansion (not being "average" myself, I just ordered a second bargain! - supply to cover my anticipated future * As advertised on page 95 of the November 1975 needs). BYTE. No more shorting across DIP leads .. . just quickly clip on an IC TEST CLIP to bring DIP leads out for safe attachment of scope Systems Research, Inc. presents - probes and other leads. !deal for signal input, trac A Complete Microcomputer for only *$575. Ing, troubleshooting, etc. The SRI-500 Patented precision, "con tact comb" design guar Include. TTY and RS-232 Inlerlace•. Connecl. 10 any 20MA loop teletype. Enclo.ed antees no shorting be In a compact, de.k lop unit, II contalnl 1K (word) RAM'" expandeble Prom, power tween DIP leads. Probes ,upply and .xtra main board connecloro 10 accepl many opllon •. The SRI-500 lerle. Rovv-To- Part Model Price can hang "no-hands" free I. d ..lgned around the new Mo.lek F-8. an 8 bll proce.. or wllh a de.lgnero develop Rovv Dim. Number ment program re.ldlng In Ihe program Ilorage unll. making programming an ...y on Test Clip terminals in TC-8 .3IN. 923695 $7.35 'alk even for the Inexperienced u ••r. card racks (unique - see TC-14 .3IN. 92369B 4.50 photo). Engineered Me • Special Introduclory oller TC-16 .3IN. 923700 4.75 •• Addillonil Ram available TC- 16 LSI .5/.6IN. 923702 8.95 chanical clamping plus TC-18 .3IN. 923703 10.00 gold-plated phosphor TC-20 .3IN. 923704 11.55 bronze terminals provide Available Options TC-22 .4IN. 923705 All items completely assembled and tested - 11.55 superior electrical con TC-24 .5 /.6IN. 923714 SRI-510 Keyboard (provides allow 6D-90 days delivery time. All items 13.85 tact. Also unequaled as a TC-2B .5/ .6IN . 923718 full keyboard control) shipped postpaid. 15.25 TC-36 .5/.6IN . 923720 19.95 DIP removal tool. $125 Send Cash or check for: TC-40 .5/.6IN. 923722 21.00 SRI-S20 Video Interface (RF ----8a. SRI-SOO $ __ea. SRI-510 $ or Video) _ea. SRI-S20 $ __ea. SRI-530 $ = $175 We honor M.C. and B.A.C. charges. Mastercharge" _ _ Interbank" ___ _ SRI-S30 Caselte Interface Add sa les tax on OH and CA orders. ~~~= ~~lt:~',~~HAN~~'~G ~.07~ $ 75 ~~nnka~~:ricard " __ Exp. Dale ___ _ (F.O.B. Painesville on company P.O.'s.1 $10.01 to $25.00 1.50 .80 Complete Blackjack game Dealer inquiries invited this chart. 25.01 to 50.00 2.00 .90 program to demonstrate or Systems Research, Inc. exercise the SRI-SOO P.O. Box 151280 (Specify paper tape or Salt Lake City. Uteh 84115 II ~ P;d;~~~n~~;~88;~~C;;;~h~d;;C;~tlons Ca.elte) free with order (801) 942-1093 of SRI-SOD (limited oller) Box 11 O-G. Painesville. OH 44077 • 216/354-210 1 Pittsburgh Group The following note was received from Eric Liber and Fred Kitman of Pittsburgh: Dear Fellow Computer Phreaks : Just a quick note to let you know thaI hobby computing and computers are al ive and well in Pittsburgh. The name of the organization is the Pittsburgh Area Com· puter Club. We had our first meeting on October 8, 1975 and even though the weather was inclement we had 15 people in attendance. In addition there is definite interest from at least that many more! Not bad for a beginning. The name of our acting president is Eric Liber and the name of the secretary/ treasurer is Fred Kitman. We can be reached at the address below or at the following telephone numbers: Day: 412-391-3800; Night: 412-276-6546. The members of the club have a total of 5 computers with 2 Altairs, 1 PDP/11, one Wang and one 8008. Not a bad start!! Pittsburgh Area Computer Club, 400 Smith field St., Pittsburgh PA 15222. Clubs and Newsletters The Santa Barbara California Club Doug Penrod, 1445 La Cima Road, Santa Virginia Seminars Barbara CA 93101 sent in a good letter describing the newly formed club which has David G. Larsen of Virginia Polytechnic been meeting at the Goleta Library. Institute and State University, Blacksburg Interested persons from the Santa Barbara VA 24061 sends in the following notice of area should contact Doug by mail or phone two seminars which will be given this coming (962-3337). The club is best described by March on microcomputer themes. the following paragraph copied from 1. Microcomputer Interfacing Workshop, Datafile, Volume 1 number 0: March 12-13, 1976. A two-day workshop The first meeting of the un-named club of based on the popular Intel 8080 micro computer hobbyists of the Santa Barbara processor. This course is sponsored by the area was held Wednesday evening at 7:30, VPI and SU Extension Division at the 1975 October 8 at the Goleta Library, 500 VPI Center in Reston VA (near Dulles North Fairview. Attendees ranged from Airport). This workshop will include many professionals to those with a keen interest hours of experience in programming and but no knowledge so far. Equipment ranged interface construction with over 12 oper from abacus and slide rule to a Data General ating microcomputers for participant use. Eclipse system. Most expressed an interest in For more information contact Dr. Norris owning a machine of their own, from pro Bell, VPI and SU Continuing Education grammable calculator through microcom Center, Blacksburg VA 24061, puter to minicomputer. Most felt that the 703-951-6328. most valuable feature of meetings is the 2. Digital Electronics for Automation and "random access" period, during which Instrumentation, March 21-26, wh ich is a members mill about and compare notes on hands on laboratory/lecture course covering their projects and problems, and examine basic digital electronics as well as data hardware brought for display and consu lta communications and interfacing using asyn tion. At the first meeting was an HP-65 chronous serial techniques. It is held at VPI (Ralph Boland), a MITS Altair 8800 (Doug and SU in Blacksburg VA and is sponsored Penrod), a MITS Scientific Calculator (Doug by the American Chemical Society, Educa Penrod), a home brew microcomputer built tion Division, 115516th St NW, Washington around an Intel 8008 microprocessor chip DC 20036 (202)-872-4528. (Larry Plate), and a "TV Typewriter" {Grant 68 Runyan). Brian Johnson gave a lecture on microprocessors and computer principles for beginners, during the random access period. -----~©@Uili)(pQO~@(fO~@@] I Everyone who is interested in any aspect of computing/calculating is encouraged to join us at our meetings. If you like mathematical ~ I games and puzzles, computer history, want to learn how computers work, want to build I a computer or calculator, want to learn programm ing - any aspect of software or I hardware, this is the place to meet the people you want to talk to. In addition to I informal exchange of information, help, and goodies, we expect to have tal ks and demon I strations by experts on occasion. We also I offer advice on publications and books. I Assemble your own electronic I Ping· Pong unit that connects I to any TV. It's easy! Complete plans, pIc boards, I preassembled & finished units. Q) Our d8Si~ns include challenging I ~ game aCtion, a computer- Minneapolis-St. Paul Computer Activities I control paddle sound effects & on·screen scoring. Exciting! I The BIT USERS ASSOCIATION is an I Build the basic unit for about $40 in common components. I organization of computer hobbyists and I Send $27.50 for "Superset" small systems engineers serving primarily the pIc board (with aligned hariz. I Minneapolis-St. Paul metropolitan area. The & vert. oscillators) & plans ... I I or . . . send $1 .00 Irefundablel members seek to exchange newsletters and for circuit diagram & info I technical data with organizations or packet of pic boards, plans, individuals with similar interests. I ~. B@O=X 4~204B ac'cessories & completed units. I The BIT USERS ASSOCIATION was $1 for schemati c diagram & info I eMOUNTAIN VIEW,P . o CA 94040 pack !reflmdable on purchase). begun in 1973 by users of the BIT 480-483 minicomputers, and remains a source for '-______.J replacement parts and licenses regarding the said machines. It has expanded to encompass persons with interest in various minicom puters and microprocessors, and is actively ANNOUNCING engaged in the design and construction of selected peripheral devices suitable for BASIC-8 USERS CRT hobbyist use and which can be built at low 1 . 1,920 character display - 80 characters x 24 lines cost at home. Raster-scan television graphic 2. Basic language with extended math functions and uniquely dense alphanumeric television 3. More powerful than many mini-computer basic systems terminals, for example, are in final stages of 4 . AvaUable 1 st quarter of 1976 development. PHONE: 617-966-0929 The sponsor of the BIT USERS ASSO CIATION is the Resource Access Center, a 9080 Microproc ...... $56.00 Replaces 8080 non-profit educational center serving com 91 L02 1 K low power RAM ...... 3.90 munity service agencies. Inquirers are 21021 K RAM ...... 2.90 requested to send self addressed stamped ASCII Keyboard Kit ...... 79.50 envelope, but no other monies please. In FEATURES: Full 55 key, Minneapolis, telephone 824-6406 (or reliable scanning logic, N message service, 823-8247). BIT USERS key rollover, TTL com· ASSOCIATION, RESOURCE ACCESS patible parallel output. Also available-serial out CENTER, 3010 4th Ave S, Minneapolis MN put, parity bit, TTY 55408. current loop output. Other kits available: 1702 PROM Programmer 125.00 Nashua NH Area Computer Club 8223 PROM Programmer 79.50 Audio cassette interface 69.50 CRT TV display Dwayne Jeffries, 181 Cypress Lane , Nashua NH 03060 notes formation of a computer club in the Nashua NH area. For MIKRA-O Inc., information and details, contact Dwayne. IMIKRA-D /'~I P.O. Box 403, Holliston MA 01746 Continued on page 70 69 Miami Area Computer Club and mathematical subroutines for floating point. Specialized functions may be added Terry Williamson, P.O. Box 430852, S. by the user. Miami FL 33143 went to the MITS Caravan The proposed syntax and grammar for seminar in Miami recently. As often TINY BASIC is described in the PCC news happens when people get together wi th paper Vol. 4, nos. 1 and 2. The design common interests, Terry got involved in philosophy is to keep it simple and use as conversations wi th several other personal little memory as possible. Speed is sacrificed. computer addicts at the MITS show. The net PCC would greatly appreciate any help result is the forming of a Miami area and ideas. Sixteen bit (double word) addi computer club. For details contact Terry by tion, subtraction, multiplication, division, mail or at 305-271-9909. Thanks to MITS decimal-binary and random number routines for catalyzing another computer club. are needed. Bernard R. Greening People's Computer Company P.O. Box 310 North Texas Group Menlo Park CA 94025 The Computer Hobbyist Group of North Texas is the name of the computer club in Washington DC Area Club Activity? the Dallas-Fort Worth Area. In a recent letter to BYTE, Bill Fuller (hardware editor Robert Jones of Washington DC is of TCHGNT newsletter) comments: interested in organizing a computer club for " ... thanks for the plugs in BYTE for the nation's capital. If you are interested, contact him at: 4201 Massachusetts Ave, the Texas Club. We went from 35 to 75 Apt. 168 W, Washington DC 20016. since BYTE appeared and that's why I'm so darn busy." The club puts out a newsletter with information on activities, and has arranged Reston VA Club? for some demonstrations by computer com pany representatives and by members who In Reston VA, Andrew Convery reports have built computers. Meetings are held that he is interested in assembling a local monthly. For latest details, contact Bill club. Contact him at 2315 Freetown Ct, Apt Fuller at 2377 Dalworth 157, Grand Prairie 11 C, Reston VA 22091. His home phone is TX 75050. (703) 860-1849, and his work phone is (703) 241-3551. News of NECC Tiny Basic The New England Computer Club held its People's Computer Company has been first meeting on November 5, 1975, at the promoting programming in BASIC. Several Jarrell-Ashe plant in Waltham MA with companies have produced inexpensive micro about 200 people showing up. As is typical processor chips. One ofthese, Intel, has made of "first meetings," the most important the Intel 8080 chip. Currently available objective was accomplished - the assembly versions of BASIC take 4 to 8K words of of a mailing list of interested individuals, and memory. identification of a small group willing to put PCC is working on a TINY BASIC. It will together a more formal organi zation. Future be oriented to: meetings have tentatively been scheduled for the Mitre Corporation cafeteria in Bedford kids having fun MA. teaching BASIC One key goal is setting up a series of games seminars on the technology of hardware and elementary school arithmetic software. Other expected activities are mathematical recreations "show and tell," trading posts for equipment send us your ideas . . . exchange among individuals, and tal ks by manufacturers or computer users concerning It will run on an Intelec 8/Mod 80 or an appl ications of the technology. A newsletter ALTAIR 8800. It will use 16 bit (double will be financed by the sale of 30 Intel 8080 word) integer arithmetic. Its design will be systems manuals donated by the local repre public so that others may reorganize the 10 sentative. 70 You can buy this microcomputer for $39.95, but... We would be a bit surprised if you In fact every part including the powerful could do anything meaningful without Me 6800 CPU and the 8K dynamic RAM additional hardware and software. MC 6800 is guaranteed for 120 days. It has the best Wave Mate's Jupiter IITMisn't the kind of software around, System Monitor and Debug microcomputer kit you only stare at ... when programs (ROM). Includes powerful text you've completed your Jupiter II just plug in editor and Motorola compatible assembler. your teletype and you're ready to go. That's And BASIC at no extra cost. Because we've because it goes beyond the sum of its high been making microcomputer systems for over quality parts. It's the ultimate micro kit 4 years, we can offer you the broadest line of experience. In performance, in documentation, interfaces including TV terminal and dual in reliability. First, consider its superb features. audio cassette. Impressive. And yet the It has small pluggable wire wrapped cards grandest feature is the experience (r) -6-=J--:::-=f}:-...... ,) easily tailored to suit your modifications. of completing a kit that works. ( J Every Ie is socketed and 100% burn-in tested. Guaranteed. W.4¥~ 11lau. IIf------~ ACT NOW AND SAVE. 0 Send details on kit-a-month club II ... Introductory price $1225. (Assembled $1885.) 0 Kit 0 Assembled ... I11III (Good until February 1, 1976) I11III II 0 Send Jupiter II Microcomputer Kit. Includes: 0 RS 232C conversion kit ( telety pe) $47.85 II .... Modular plug-in power • Rack mount module cage 0 I'm not convinced; send me 101 reasons why. ... I11III supply • Wire wrap tool 0 PI d f J . lIS I I11III .... 9 module PC backplane • Wire unwrap tool ease sell ree u plter . ystem cata ogue. II I11III • CPU module • Cables. connectors, all .... System moni tor module other necessary 0 Check enclosed for $ II I11III • 8K dynamic RAM hardware Include $10.00 for postage and handling. California ...... module • Softwa re (edi tor, debug, residents add 6% tax D elivery 60 days ARO I11III I11III • Seri al R S 232 assembler, BASIC) ... II communication interface • Assembly manuals 0 Master Cha rge # ------I11III module • Operators manuals 0 B k A . d # ... II • Front panel module • Theory of operati on an menca r I11III .... Front panel manuals C redit ca rd expires on II I11III • Wire; cut, stripped, color • Annual membership in . II coded. users group N ame II , Address II City/State/Zip _ WAVE MATE II 1015 West 190th Street Gardena, California 90248 II Telephone (213) .~7.~:~~~:...... II (--L nl...... l S WARRANTY E II L~ I) i 120 days on all parts, i II : materials and workmanship. : II -!~~~~~~~~~~~~~~ 71 Permission Granted to Xerox (or 3M, IBM, A peco or otherwise jitcsimile, copy or duplica le) BYTE SUBSCRIBERS Will lEARN ... Abo ut all of th e new small systems co mi ng on the market ... whi ch are real and which are still in development stages ... there will be a simple se ri es of articles on computer languages . .. revi ews of kits . . . in fo on surpl us bu ys and use d equipment . .. circuits for building your own equipment . . . di sc us sions of stand ard s .. . news of use r clubs and programs avail able ... info on specia li zed newsletters ... ga mes and ga me gro ups ... game progra ms . . . computer art . . . computer music ... and if th at doesn't cover it, all you have to do is write in and eith er say what else you want or else start writing the articl es yourse lf. BYTERS SAVE ... With single copies go ing fo r $1.50 (i nsane price ), the $12 subscription pri ce begi ns to lo ok attractive. You won' t want to miss a copy (presumabl y), so fill in the coupon here and se nd it in quickly ... no cash needed, just se nd it in , we'll put you into the sub sc ription computer (with fin ge rs crossed) and send you th e in vo ice . It's pro babl y a business expense, ri ght? If you dislike ripping your soon to be valu abl e issu e of BYTE to shreds by removing a co upon, yo u are hereby given permi ssion in perp etui ty (until sub sc ription ra tes go up) to vi olate th e copyright and make a copy of any one of the fo ur coup ons .. . nea tn ess coun ts. Your fri ends may do likewi se, unless you are a lot less persuas ive th an we thin k you are . The Management r------Cut------r------Tear------i I I I I Name ...... i Name...... I I Address ...... I Address...... • ...... I I I I I City ...... State ...... Zip . . . . • . . I City ...... State ...... Zip ... . . " I l O BI LL ME 0 Check for $12 enclosed : 0 BI LL ME 0 Check for $12 enclose d i I 0 Bill BankAmericard or MasterCharge # ...... , 0 Bill BankAmericard or MasterCharge # ...... , I , I I L------L------l' I Shred I Rip I I I I Name . . . . . •..•...... • ...... : Name ·· · ·· · · · · · · · · · · · · ·· · · · · ·· ···· · · ·· · ·· · ·· · · ··· · ····· 1 I Address ...... I Address ...... I I City ...... State ...... Zip ...... I City ...... State ...... Zip ...... I I I I I D BILL ME D Check for $12 enclosed I D BILL ME D Check for $12 enclosed I I 0 Bill BankAmericard or Ma sterCharge # ...... I 0 Bill BankAmericard or Ma sterCharge # ...... \ 11 I I L ______-1 ______.J • BYTE. Peterborough NH 03458 72 MilS Computer Caravan The Mighty MITS Mobile stopped off in puter systems. MITS is reportedly going to Boston recently and roused the micropro have this ready for use in a few weeks. This cessor byters from the woodwork. It was a certainly will be a major step toward pro good deal like a club meeting as the MITS viding low cost complete operating com Computer Caravan paused to provide a puter systems. seminar for 30 plus enthusiasts. The MITS line printer is also about to be Since it is more than likely that virtually released, complete with its operating system, everyone who is reading this brief report and magnetic tape memories are in the was to some degree snared into the com works. Considering that all this really started puter hobby field as a result of the Altair only about one year ago, the progress by 8800, we won't try to explain who MITS is MITS has been just about incredible. or what they make. The MITS Caravan was thoroughly But reading about the Altair and seeing it enjoyed by everyone and it seems likely that in action are two different things, so the as a result of the group getting together for crowds have been catching the Caravan in that seminar that a club will be forming ... large numbers. It's a good show, so don't another feather in the cap for MITS. This miss it when it comes around. The registra sort of thing has been happening all around tion fee is $12 and for that price you get a the country. - loose leaf binder with schematics of the Altair and notes to go with the short instruction course presented during the Caravan seminar. The book alone makes the price reasonable. You also get an oppor tunity to see the Altair in action and ask questions until you get tired. The 8800 on demo had a teletype 10 and a cassette memory unit, which is what most of us were anxious to see and tryout. The program was a good one, starting out with a discussion of the fundamentals of computers and logic, then the Altair hardware, and finally the software with a demo of MITS BASIC. A couple of non-beginners went out for a short snort or something while the introduc fastest, most reliable tion to logic circuits unfolded .. . everyone method known ... to build, test else listened with interest. The session was and modify experimental circuits run by Mike Hunter, who has been driving 8-bus distribution system High-performance A P Super the Caravan all around the country. plus universal .1" by .1" matrix Strip component matrices consist of solderless. plug-in tie points of 128 terminals of 5 tie points The standard modem tones of 2025 and all in one integral device. each. The 8 buses of 5 connect 2225 Hz were used for the cassette storage Accepts all DIP's and discretes ed 5-tie-point terminals are for with leads up to .032" dia. voltage, ground, reset and clock ... which seemed like a good feature. After lines, shift command, etc. New, a short loading program via the front panel Interconnect with any solid wire non-shorting, instant-mou nt up to No. 20 A.W.G. backing and quick-removal switches BASIC was loaded from a cassette screws are supplied .. . use several and demonstrated. This certainly appears to ORDER BY PART NUMBER Super-Strips to create large-scale be a very good version of BASIC and to have 923252 (nickel·sil,,, "nninal.I ...... $17.00 breadboards on panels up to 923748 (gold·plat.d"nni"I.I ...... • $18.90 1/8" thick. a lot of advantages over other possible We honor M .C. and B.A .C. charg es. Add_ SHIPPING/ HANDLING C.O.D. languages. Add sales tax on OH and CA orders. fees from Up 10 $10.00 $1.00 $ .70 The soon to be released floppy disk (F.O.B. Painesville on company P.O.'s.) Dealer inquiries invited this cha rt. j~~?~~0s6~OO ~ : ~ :: operating system was discussed. This will make fast access bulk memory available for a very reasonable price as compared to com mercial units now available for the minicom- 73 ALTAIR OWNERS CMR PRESENTS That Didn't Take THE MEMORY YOU'VE BEEN WAITING FOR long at All 8K x8 DYNAMIC RAM In the November issue of BYTE we ON ONE PLUG-IN CARD FOR published Dan Fylstra's article "Son of Motorola," comparing the new MOS Tech ONLY 00 nology 6501 and 6502 computers with the $599 * Motorola 6800. At the time the article was written (l ate August) he could not pred ict • FACTORY ASSEMBLED AND TESTED when a kit would be available for the MOS • PLUGS INTO 8800 WITH NO MODI FICATIONS T ec hnology processors. • PROTECT-UNPROTECT CIRCUITRY INCLUDED The f irst MOS T echnology 6502 kit is TO MATCH 8800 now availab le: Microcomputer Associates • TWO 4k BLOCKS OF DYNAMIC R.A.M. Inc., of Cup ertino, California, have • USER OR FACTORY ADDRESS PROGRAMMING ann o unced the JOLT computer kit. (SPECIFY) According to their news release, this kit • EACH CMR-8080-8k is SHIPPED WITH AN EDGE combines hardware and software for small BOARD CONNECTOR INCLUDED. scale computing at a low cost. • EXPANDER BOARDS AVAILABLE (ADDS FOUR Components of the JOLT include the SLOTS TO 8800) ce ntral processor kit, a 4096 byte RAM kit, an 10 interface kit, powe r supply kit, and miscellaneous items such as a uni versal TEN REASONS TO CHOOSE prot otyping card and an accessory kit. The bas ic central proce ssor card conta ins THE CMR MEMORY CARD 512 bytes of programmable random access 1. 300ns ACCESS TIME memory, 64 bytes of interrupt vector ran 2. TWICE THE MEMORY DENSITY dom access memory, and 16 fully program· 3. LESS $$ PER K OF MEMORY mabi e 10 lines. The most important feature 4. DESIGNED FOR THE 8800 of the CPU card is its read onl y memory. 5. USES THE LATEST T.I. CH IPS This memory contai ns the DEMON (DEbug 6. G-1 0 EPOXY BOARDS MONitor) progra m product, a basic software 7. PLATED THROUGH HOLES. element nee ded to run the system 'f rom the 8. GOLD PLATED CONNECTOR CONTACTS. serial terminal interface, which is imme 9.8192 WORDS OF DYNAMIC RAM diately availabl e when you turn on the 10.90 DAY WARRANTY ON PARTS AND LABOR powe r. *ORDERING NOTE: Classified Ads Available for FOR FACTORY PROGRAMMING. SPECIFY TWO 4k MEMORY ADDRESS LOCATIONS FOR EACH CMR·BOBO·Bk Individuals and Clubs MEMORY CARD ORDERED. Readers who have equipment, software or oth er items to buy, sell or swap should send i~ a clearly MAIL THIS COUPON TODAY typed or printed notice to that effect. The notices D ENCLOSED IS CHECK OR M.O. FOR $ ______are free of charge and will be printed one time only D C. O . D . s ACCEPTED WITH 3 0 % DEPOSIT. TOTA L AMOUNT $ 3 0 % = ______on a space available basis. Insertions should be limited to no more than 100 words. Notices can be VA. RESIDENTS ADD 4 % • PLEASE SEND ___ CMR·8080·8k CARD{S)' AS accepted from individuals or bona fide computer DESCRIBED ABOVE @ 599.00 EA. POSTPAID users' clubs only. Commercial advertisers should .PLEASE SEND ___E X PANDER BOARD{S) contact Bill Edwards, BYTE advertising m anager, (ADDS 4 SLOTS TO 8800) BOAR D ONL Y @ 15.00 EA. for the latest rate card and terms. POSTPAID TO : NAME ______ALTAI R 8800, assembled, tested, and completely ADDRESS ______operational includes 1 K RAM board with 256 w ords. Complete documentation including news· CITY______STATE & ZIP______letters, quality built by electrical engineer. ON L Y $500 postpaid. D . Schreiter, 9032 Whit~haven Dr, St. Louis MO 63123. CMR COMPUTER MANUFACTURING CO. P.O. BO X 167. 1921 DOGWOOD LANE Would very much like to buy a used memory board VIENNA, VIRGINIA 22180 (or two) for a Raytheon 704 minicomputer . R ick Loomis, PO Box 1467, Scottsdale AZ 85252, (602) 994·9104 (cal l afternoons or late at night). 74 The DEMON program includ es routines to display and alter registers or memory, and control termi nal interface service routines. DEMON also includes a breakpoint capa bility useful in debugging programs, two A PRECISION kind s of formatted memory read and write operations for program loading and saving, a hi gh speed 8 bit parallel input routine and WAVEFORM several 10 serv ice routines which may be ca ll ed by a user's program. Perhaps the most unique feature of the GENERATOR DEMON program is its adaptable terminal interface service routine; the software senses and automatica ll y adapts to the speed at AT APRICE YOU which the terminal operates between 10 to 30 characters per second . A minimum system built with the JOLT components ca n be asse mbl ed from the CPU CAN AFFORD. card kit, the accessory kit, and a Teletype or RS-232 compatible terminal. With such a system, many of the basic concepts of programming can be demonstrated within the confines of a 512 byte area of user memory. Inpu t and output operations can take advantage of the DEMON subroutin es to interact with the terminal. This would make a good initial system for a person to learn the ropes of computing. As programming sophistication increases the owner may expand the memory by purchasing additional boards. For users who want to breadboard their The Hickok own peripherals, the universal card will come Model 270 Function Generator in handy as a starting point for an interface gives you a lot more waveform construction project. generating capability than you 'd For ordering information and prices, con expect for its price. tact Microcomputer Associates In c., at 10440 N Tantau, Cupertino CA 95014, • Puts stable, calibrated, high 408-247-8940. Delivery is 30 days after quality sine, square and rece ipt of order accordi ng to their news triangle waveforms from 1 Hz release . • to 500 kHz at your fingertips. • With external connections MICROCOMPUTER EXPERT NEEDED. I ' ll pay for the eq uipment. You put it together. We'll both you can produce logic use it once it's running. I'm tired of paying $1 ODD's pulses, sweeps and ramps , to a 370/ 155 batch processing service. My interest is statistic al analysis of large volumes of stock AM and FM outputs, phase market-type data. I need a powerful (for a micro) and frequency shift keying system, with disk or disk-type orientation, tape capabilities, line printer, card reader (maybe), signals, tone bursts and more. BASIC or FORTRAN compiler, telecommunica tion ability. Joe Schachter, 41 Amory St. , Cam • I(s an audio generator and bridge MA 02139. (617) 492·2765. much more. USED MICROCOMPUTER EQUIPMENT NEEDED. See ad above. AT YOUR DISTRIBUTOR $16600 ASR -33 TELETYPE in perfect physical and oper ating condition; 20 mA current loop interface, w/reader power supply and pedestal - $ 500. Also, Kleinschmidt drum printer with parallel ASCII , HICKOK TT L -compatible interface, 30 cps in perfect oper ating condition, w/o dress cover - $300. (617) 757-2037 after 6 pm. D . F . Craft, Jr. the value innovator For sale, DEC PDPB/ L mini computer. The com · INSTRUMENTATION & CONTROLS DIVISION puter is 100% working and in excellent condition. THE HICKOK ELECTRICAL INSTRUMENT CO Hardware: 4K core, TTY interface, Pos I/O inter 10514 Dupont Avenue. Cleveland. Ohio 44108 face Pos I/ O bus board. Software: editor, diag· nost'ics, assembler, other misc. Price $900. Call (216) 541-8060 TWX 810-421-8286 617·592-2937 evenings. Peter A Balkus, Lynn MA. 75 You'll Want to Nybble at these Byte Books Where does the editor of a computer magazine turn to when he must verify some author's hardware design? Information on a 75450 interface gate, or a 74147 priority encoder circuit does not spring forth by magic. Checking the information supplied by authors is part of BYTE's quality control program. When you build a project, you need this same sort of information. All you find in the advertisements for parts are mysterious numbers identifying the little beasties ... hardly the sort of information which can be used to design a custom logic circuit. You can find out about many of the numbers by using the information found in these books. No laboratory bench is complete without an accompanying library shelf filled with references - and this set of Texas Instruments engineering manuals plus Don Lancaster's TTL Cookbook will provide an excellent starting point or addition to your personal library. • The TTL Cookbook by Don Lancaster, published by Howard • The Semiconductor Memory Data Book for Design Engi W. Sams, Indianapolis, Indiana. Start your quest for data here with neers, by Texas Instruments, Incorporated. Don't forget the Don's tutorial explanations of what makes a TTL logic design tick. importance of memories to your systems. Refer to this 272 page 335 pages, $8.95 postpaid. manual to find out about the T.I. versions of many of the popular • The Supplement to The TTL Data Book for Design Engi random access memories and read only memories. Order your neers, by Texas Instruments Incorporated. What happens when personal copy today, only $2.95 postpaid. you can't find a 7400 series device listed in The Data Book for DesilJl Engineers? Before you start screaming and tearing your • The Linear and Interface Circuits Data Book for Design hair out in frustration, turn to the Supplement. The Supplement Engineers, by Texas Instruments Incorporated. When you run has 400 pages of additional information including a comprehensive across one of those weird numbers like 75365 the immediate index to both TTL Data Book volumes. To be complete (and keep frustration problem occurs again. What kind of gate could that be? your hair in place and vocal cords intact) you'd best order the We won't tell in this ad, but you can find out by reading the supplement at $1.95 to accompany the main volume. specifications in The Linear and Interface Circuits Data Book for Design Engineers. You can interface your brain to the 72xxx • The Transistor and Diode Data Book for Design Engineers, (linear) and 75xxx (interface) series of functions by ordering your by Texas Instruments, Incorporated. You'd expect a big fat data copy of this 688 page manual at only $3.95 postpaid. book and a wide line of diodes and transistors from a company which has been around from the start of semiconductors. Well, its available in the form of this 1248 page manual from T.I. which • The TTL Data Book for Design Engineers, by Texas describes the characteristics of over 800 types of transistors and Instruments Incorporated. How does an engineer find out about over 500 types of silicon diodes. This book covers the T.I. line of the TTL circuits? He reads the manufacturer's literature. This 640 low power semiconductors (1 Watt or less). You won't find every page beauty covers the detailed specs of most of the 7400 series type of transistor or diode in existence here, but you'll find most TTL logic devices. No experimenter working with TTL has a of the numbers used in switching and amplifying circuits. Order complete library without The TTL Data Book for Design your copy today, only $4.95 postpaid. Engineers. Order yours today, only $3.95 postpaid. Caution: Heavy Reading Buyers of these books should be cautioned: heavy reading will be required. These books are so filled with information that they weigh in at a total of about 190 ounces (5387 grams). On the basis of sheer mass, these books have got to be the bargain of the century. Make sure that you use a structurally sound book shelf and above all avoid dropping one of these books on your foot. But the mass of these books doesn't affect the bargain: we pay postage on all orders shipped to addresses in the USA and Canada, so the prices you see are the prices you pay. (That's only $.005 per gram on the average.) __ TT L Cookbook @ $8.95 Send to: N"-'-"'am=e ______TTL Data Book @ $3.95 Address __ Supplement to TTL Data Book @ $1.95 __ Linear and Interface Circuits @ $3.95 City State Zip __ Semiconductor Memory Data @ $2.95 o Check enclosed __ Transistor and Diode Data Book @ $4.95 o Bill MC # ______Exp. Oate ____ o Bill BA # Exp. Oate _____ ~~TI PETERBOROUGH, NH 03458 Signature 76 '61( MEMORY I(/T YTE'S LESS THAN 5.5'IWORD 16,384 8-BIT WORDS ON BUGS ON ONE CARD WITH PIGGY-BACK ONL Y Here lies documentation of k nown bugs detected in previous editions of BYTE . .. $895.00 • PLUG DI RECTL Y INTO 8800 • LOW POWER: + 8 TO +10V, LESS THAN 600 mA Roger Frank, 1801 E Girar d #247, Engle +15 TO +18V, LESS THAN 125 mA wood CO 80110 points out the following -15 TO-18V, LESS THAN 30 mA error in the text of Jim Hogenson's " Build • 4K WITH PROTECT-UNPROTECT An Oscilloscope Graphics Interface," page • USES LOW POWER SCHOTTKY TTL 72 of BYTE # 2: The description of control • MEMORY CHIPS SOCKET MOUNTED code 7 at the top of the third co lumn should .50/50 GOLD-PLATED EDGE CONTACTS read : "Control code 7 wi II not set Z, bu t wi II • EPOXY BOARDS WITH PLATED THRU HOLES decre men t the X coord i na te of the di sp l ay . • JUMPER PROGRAM 16K ADDRESS SLOT Thi s changes the hor·izontal section of the .8080 HOME BREW COMPATIBLE counter on ly, without affecting stored data • 420nS ACCESS DYNAMIC RAM in the memory of the interface unit." • NOT A FLAKE Th e remaining portion of the ori gi nal INTRODUCTORY SPECIAL ON ORDERS paragraph describing the 0 an d 7 cod es RECEIVED BEFORE 1/ 1/76 should be deleted, through the words •• Take $50 Discount •• Take Free 50/50 Edge Connector " decrement X contro l code ." •• Pay No Shipping Charges WRITE TO DA VE (K6LKL) at BYTE #4, page 35, tab le 3: The Bau dot co de for the letter Q in the table should read *SPECI FY KIT 16KMDY *CALIF. RES. ADD SALES TAX " 1 1 1 0 1." DUTRONIGB P.O. Box 9160, *MASTER CHARGE - OK Stockton CA 95208 *BANKAMERICARD - OK ANSWERS TO DECEMBER (X, Y) CO-ORDINATES DIRECTION WORD HUNT page 18 4, 3 :*: 5 3 4 ACCUMULATOR 1,3 8 DTL e 16,10 2 MICROPROCESSOR 8,11 2 ADD (not in address) 4,12 2 ECL 9,2 8 MNEMONIC 17,2 8 ADDRESS 1,15 8 EXECUTE 12,17 6 MOS 8, 1 8 ALPHANUMERIC 1,1 2 EXIT 10,17 8 OCTAL 6,13 2 AND 4,3 1 FALSE 15, 10 4 PCB 20,14 5 APL 6,4 5 FETCH 14,4 8 PERIPHERAL 18,1 8 ASCII 16,7 6 FILE 7,7 5 PLOT 12,9 8 ASSEMBLER 19,12 7 FLAG 5, 14 2 POINTER 3,1 8 ASYNCHRONOUS 19,12 4 FOCAL 5,14 6 PRIORITY 14,19 2 BASIC 13,10 4 FORMAT 5, 14 3 PROGRAM 4,8 1 BATCH 8,5 5 FORTRAN 7,20 2 PROM 12,9 5 BAUD 2,20 2 GATE 2, 12 4 QUEUE 2, 7 1 BCD 3,10 1 GLOBAL 11,13 2 RAM (not in program) 8,12 2 BET 9,21 2 HALT 7,3 7 READ 19,17 4 BINARY 12,8 4 INPUT 6 , 6 7 RECORD 11,8 4 BOOLEAN 13,10 7 INSTRUCTION 20, 2 8 ROL 14,2 1 BRANCH 9,21 4 INTERFACE 20,21 6 SOURCE 2,18 2 BUFFER 14,17 2 INTERRUPT 20,21 4 STACK 16,9 4 BYTE 9,21 6 JUMP 2,8 1 STATUS 11,9 6 CHECKSUM 1,4 1 LED 3, 17 2 STORAGE 17,14 6 CHIP 14,7 8 LINK 2,21 2 SUBROUTINE 21,14 4 CLOCK 9,17 7 LIST 17,12 8 SUBSYSTEM 8,3 8 COBOL 13,1 8 LITERAL 13, 18 2 SYNTAX 21,20 4 COUNTER 7,13 6 LOAD 2,1 8 TABLE 12,12 2 DATA 6, 5 4 LOCATION 12, 13 5 TRANSMITTER 10,16 2 DEBUG 6, 5 2 LOG 14, 3 2 TRAP 11,21 4 DESTINATION 2,15 2 LOOP 4,2 6 TTL 3,5 2 DEVICE 1, 16 2 LSI 12,10 6 VCC 14,1 6 DIAGNOSTIC 10,2 8 MATRICES 8 , 11 3 VECTOR 3,16 4 DIODE 21 , 1 8 MEMORY 19,20 6 VERIFY 3,16 1 DISK 12,18 3 MHZ 9,6 8 WIRE 4,19 6 DISPLAY 21,1 6 MICROCODE 17,2 6 WORD 4,19 5 77 Hit the deck in shorts and a tee shirt. Or your bikirii if you want. You're on a leisurely cruise to remote islands. With names like Martinique, Grenada, Guadeloupe. Those are the ones you've heard of. A big, beautiful sailing vessel glides from one breathtaking Caribbean jewel to another. And you're aboard, having the time of your life with an intimate group of lively, fun loving people. Singles and couples, too. There's good food, "grog;' and a few pleasant comforts ... but there's little resemblance to a stay at a fancy hotel, and you'll be happy about that. Spend ten days exploring paradise and getting to know congenial people. There's no other vacation like it. Your share from $245. A new cruise is forming now. Write Cap'n Mike for your free adventure booklet in full color. Name Address C,IV Slate Z'P Phone P.O. Box 120, Dept. 121 Miami Beach, Florida 33139 78 CONTINENTAL $1595 SPECIALTIES . PROTO BOARD 6 JE801 D:VM TheJE&:llisalhreeandonehaNdigit.autopolarity The PB·6 le iSthe user tcsl an(! bUild !..~ digital vol1melcr. ina ki t lorm.ltlcalurcsseve ral cirCUits wi thout soldering or patch t , ' . ' $j l. op lionsnol available in nny com mercial digital vol· cords: all interconnections between ": lmeler.llSiowcostispcrhapslhemoslimportanl componems are mad~ wilh com- lealure . .." .. hichisachievedbyofferingilinakil10rm . ""7",,"=~~ .. _ mon 1122 AWG hook-up wire . Thi s A kit allows lhe unil 10 be used by small OE M's quality brcadboardingkit inludes 8080A $39.95 wherccosl cllcctiv enes s is an imporl an t factor. and 630 componen t tic p,ints at I 8080 AND 8008 SUPPORT COMPONENTS by the hJbbyist who has 10 be concerned with cost. ttlan2.5ceach. ltmCJ!ures6"long 8224 CLOCK GEIlER .... TOR USED TO GENER ....TE TWO PHASE 74LS138 DECOOER PERFECT FOR DECODING THE THREE The unit also lea1Ures on card regUlators. allowing it by ~ ...... 'de . Des ig ned specially to CLOCK NEEDED BY THE 8080 $12.95 10 be operated otf a Single plus and minusliltcen BreadboHd Micropr oce ssor Cir 8008 STATE LINES IfHO 8 USEABLE LINES FOn ADDRESS LATCHING $3.98 voll. unregulated power supply. The uni t has a cu it s $15.95 8228 SYSTEM CONTROLLER GtNERATES A SYSTE M DATA small si1/! 01 three inches wid th. threc and three 82128 BIT INPUT OUTPUT PORT DIRECTLY INTEflFACES Quarters of an inchlenglh. and one and a Quartcr PROTOBDAAD100 BUS AND CONTRO L SIGNALS FOR MEM ORY $21 .25 WITH THE BJ80 TO PROVIDE lIO INTERFACE $5.75 Inch hei~ht. A lo w cost. big 10 Ie capacity !lIeadboardkrtwl:hall lhCQuahtyol CPU'S nAM 'S DT sockctsandltlcbcst oilllcProlo 8008 8BITCPU 519 .95 1101 255X l STATIC 52.25 $39.95 Per Kit printed circuit board BOJrdSCflcS complete down to 8080 SUPER 8008 39. 95 1103 1024Xt DYNAMIC 5.95 the las t nUl , bo_ and scr ew . In 40~0 ·:BIT 8080 39.95 2101 256Xl STATIC 6.95 ciudes 2 OT· 35S Sockets: lDr·35B SR'S 2102 1024Xl ST ATIC 2.95 Bus Strip: :2 5· w~y binding posls : 4 2504 102~ OYNM,llC 59.00 2107 ,1096Xl DYNA MIC 19 .95 JE803 PROBE rubberlectscrcws. nut s. bollS: an!! 2518 HEX 32 Bil 7.00 2111 256X;1 STAT IC 7.95 1"1"' ["'1"' 1' ,,, 1,,·,, .• ,,,,,1,·,1> ,,,, ,, 1,"lh,· easy assembly Instructions. 2519 HE X ~ O BIT ' .00 7010 1024Xl MIlOS 29.95 "",,' 1',11 1 "" 1o ·S I" ·,,,,I,I,· '" 1" ,,, 1,1,· ~I"){. ''''', $19,95 252 J 512 DYNAI," C 3.50 7489 15X4 STATIC 2.49 "H pr 1.",,11,,·\ TTL. IllL. flll. . Cr.·IOS tT 2525 1024 DYNAMIC 6.00 810 1 255X4 STATIC 7.95 ,It'""", II,,' I"'W,'I ,I ,,, ·,·,j'I""I,,,, .,T,·d,,,·,,!IV 2527 DUAL 25GBIT 3.95 8111 256X;1 STAT IC 7.95 " It , ot :Il,' "''':1,, 1 ""d," r,·". dt." """1 ",: .",' ! Brinll tC leallslrompcboardlorlaslsignailracing 2529 DUAL 512 BI T '.00 8599 16X;\ STATIC 3.49 10 ",,.. m." I I ""., ., ~. l:\ NJ "'.," ",,: ,,, and troubleshooliog. Inlectsignals. \'Jlfeunuse JOLT SYSTEM DESCRIPTION JOLT I/OCa rd!perlpherilllnlerlaceAdapler)-2PIALSI JOLT RAM Card _ FullystatIC.I .095 by1esol RAM With I chipS. 32 liOhnes. fourintcrruptlines, on·board dccoding microsecond acces s time and on ·boa rd decoding. Hard · and slan dard TTL drive. Fu lly programmable . Manuals In· ware and assembly manuals Iflciu ded. AVAILABLE FOR el ud ed. AVAILABLE FOR IMMEDIATE SHIPMENT . 595.50 IMMED IATE SH IPMENT . 5199 .95 kit S285 assem· kil 5140 assembled bled . JOLTUniversaI Ca rd - Samesize(4 V, ·· x7··).sametorm That were desl!ln~d lor Clock type ap· JOLT Power Supply _ Operat el: al ... 5, ~12 and ~ 1 0 lac tol as O1hel JOLT cards . Completely blank. drilled to pllcJtlOn s. l1 0Vacprlmary@50Hz. voltages. SUPPOf1S JDLT CPU. 4kbJ'lcsol RAM and JOLT 3ct:cpI14.16.240r40pin soc kels . Usedforadditlonal SlICondar ics : 8·10Vac@ I/OCJrd-or. CPU and 8 l/Dwds. Manuals included . uscr memo ry or 110 con tr ol panels. TV inlerlaces 300 mA·200 rnA AVAILABLE FOR IMMEDIATE SHIPMHH. 599.95 kit. Sl~ 5 kC'l'boards. LEOs . orolher interface logic. AVAILABLE FOR 5O Vac @30mJ..·50mA assembled . IMMEDIATE SHIPMENT . 524 .95 Excellenl lor minillure power supplies 8gasdiscl'largedisplays JOLTA ccessll rvlla ll-Contain s~noughhardwarelocon· JOLT1-5 VBoos terO p1fon _FitsontoJOLTPo werSupply necloneJOLT card to another. Such neCeSs,1ry item s as lIal C<1rd . Suppo rt sCPU ,1 6kbytesoIRAM - or,CPUamI8k SPE CIA L ca!!le.connectors.cordspace s.ha'dw3re .elc. AVAILA8LE byt es RAM and8 110 card s -or. CPU and 4k byles RAM FOR IMMEDIATE SHIPMENT. 539.95. and 161 '0 cardS Manu als included. AVAILABLE FOR 1M· MEDIATE SHIPMENT. 524.95 MULTIPURPOSE KEYBOARDS tDffiII WIRE WRAP WIRE AWG COLOR 25 FT. MIN . SOFT. 100FT. 1000 FT . 30AIVG WHIT E 52 .10 52 .75 $3.50 524 .00 30AWG YELLOW 2.10 2. 75 3.50 24 .00 30 AWG RED 2.10 2.75 3.50 24 .00 ELECTRONIC ROULETTE 30AWG GREEt! 2.10 2.7 5 350 24 .00 30AWG BLUE 2.10 275 3.50 24 .00 Complete k it 30AWG BLAC!oi 2. 10 2.75 3.50 24 .00 with all WIRE component s AWG CO LOR 25 FT MIN 50 FT AWG COLOR 25 FT MJN 50FT case and Vector Wllmg Pen:i!P I73consislsolahandheld lea therwl"!ight(und€rone 1G RED 53.80 55. 05 24 RED 51.55 52 .05 transformer. olmcc) tool which IS used to guide and wrap insulated wirc. led 011 a 18 GflEEN 53 .25 54.30 26 GREEN SI.45 5\.90 sc ll·contJm cd replaceable bobb in . onl0 compon ent leads or termina IS instal· 20 WHITE 57.55 53 .·: 0 2B WHITE $1.25 51 .65 led on pre·punched " P" Pattern Veclorbo rd ' , Conneclions betwee1 lhe 22 BLACK 51 .90 52 .55 JO BLACK 51.25 $1 .55 wrapped wif e and component leads. pad s Of te rminals are made by so ldHing. TO ORDER: SPECIFY GUf"G: COLOR MlD FOOTAGE (25 FOOT MINIMUM) ~Oijlllli ',,\\ Complete with 250 FT of rcd wire . $9.50 ea. 6' 2 CONDUCTOR POWER \. .! .. : 115 VAC REPLACEMENT WIRE - BOBBINS FOR WIRING PENCIL CORDS 125V @ 5A ----....~ , 3/1$ W36·3·A ·Pkg,3 (Gree n) $2.40 8" x 8" x 1" ..~ THREE CONDUCTOR POWER SUPPL Y CORDS W36·3·B·Pkg.3 (Red) $2.40 ~ A 56 page book on the facts W36·3..c-Pkg.3 (Clear) $2.40 NUM8ER LEN GTH AWG 0.0. RATING COLOH PRICE W36-3·Q·Pkg,3 (Blue) $2.40 17236 6 18(41X34) .255 1250W BLACK Special.9gea. of Rou lette included. $29.95 Per Kit lOA·125V 17237 18(41X35) .253 1250W GREY 1.25 9V BATTERY CLIP lOA·125V STANDARD CLIP ~O .. 17238 18 ( ~I X3 4 1 .255 1250W BLACK Special .99 ca . FOR USE WITH 9V ~ "\ - lOA·125V 17239 18(4IX34) 253 1250 1'1 GREY 1.30 Comp lete kit ~~;~~ I S:~~~;TTE RI ES 9 / $.95 10A·125V wi th all 17000 IB( J1 X34) .253 1250 W BLACK .59 10A·125V components case and TERMINAL STRIPS ~ S a tisfaction Guaranteed . $5. 00 Min. Order. U.S. Funds. transformer. ~~~I~~TEJiI~~N~~NTER 0 California Resident s - Add 6 % Sales T ax TERMINAL USED FOR MOUNTING 1 .00 Write for FREE 1976 Catalog - Data Sheets .25¢ each 115 VAC AMP TERMINAL PINS TERMINAL PIN S FOR MOUNTING COMPONENTS ALSO PERFECT FOR USE WITH BOARD CON NECTORS poR!.! ?!!g~2 A 56 page book on the facts AND SUBASSEMBLIES $1 .00/100 pes. PHONE ORDERS - (415) 592-8097 o f Craps included. $19.95 Per Kit Sphere Rolls into Town On a recent Friday evening the chaps etc. Since this is the major potential for from Sphere demonstrated their system to small computer systems this is certainly an about 50 interested computer hobbyists at a enlightened approach. As more and more downtown Boston Holiday Inn. computer stores open up around the country The show was a Despite an almost incredible schedule, a and literature such as that provided by resounding success ... good show was put on. Mike Wise, the Sphere is gotten out to the owners of small president of Sphere, was rocking a little after businesses, sales of these systems cannot be several days of going almost 24 hours a day but astronomical. ... the caravan had driven in from Toronto The Sphere sales literature is extremely that day! ... and it was an every day a well done ... and best of all, it is written for different city deal. the businessman, not the computer expert. The product was certainly impressive ... Computer stores should have little trouble in a computer built into a box the size of a selling this approach to the business world. video display and keyboard unit. That long The utter simplicity of the system will row of switches and LEDs on most CPUs has certainly appeal to the businessman. been replaced by a little PROM software The PROM has quite a repertoire and chip which permits programming to be done includes an editor, assembler, debugger, via the keyboard. command language, cassette loader, dumper and utilities ... all on a 1 KB chip! Since the It was most pleasant to see the system programming is on a PROM, this still leaves turned on and come up ready to be used. the entire 4 KB RAM available for the user The operating system is all built right into it and doesn't tie 1 KB of it up just with the in the PROM so not even a short loading operating system ... a big plus even at program has to be switched in to get it today's low memory prices. working! The PROM operating system permits The Sphere system consists of the rather sophisticated editing techniques Motorola M6800 microprocessor wi th an including movement of the cursor with ease, ASCII keyboard and interface to the 6800, a scrolling of the lines of text through the video display generator system, the Motorola buffer memory, delete lines, add lines, loader, small operating system and monitor. modify lines, etc. The system also permits At $8 60 for the complete kit this is quite a the keyboard to be used for entering pro package. grams into the computer using hexadecimal The Sphere requires an external television or octal notation. It also enables the user to set for a monitor. It will feed video to this look at any address and see what is there . . . monitor, or a few parts can be added to the change the data if desired ... an d then scan video output board which will generate a on through succeeding bytes. Not a bad signal which th e TV set can pick up via its bunch of programs to be crammed into one antenna terminals. Some problems with FCC 1024 byte PROM! licensing of transmitters seems to have held Another plus is the comprehensive Sphere up the supplying of these parts with the kit book of instructions. It is not only itself. amazingly complete (particularly when you Mike told the group that they are well consider how short a time the company has along with a BASIC language package for the been in existance), it is also written in system and that they expect to have a language which is not beyond the relative library of about 4000 business oriented newcomer to computers. programs available. In all, the show was a reso unding success The Sphere literature stresses the business in Boston and a tired, but happy Sphere applications of the system, showing it in use crew packed up for the next night in New in offices, stores, homes, banks, laboratories, York. _ 80 THE SUNTRONIX MODEL KBD IV Keyboard is ideally suited as a general purpose ASCII Keyboard for data terminal applications. This keyboard more than meets the needs of the data entry market for long life and reliability. The KBD IV utilizes the 2 key rollover solid state read-only MaS memory allowing encoded outputs to be strobed out as each key is depressed. A second key may be depressed concurrent with the first, but the second key encoded output will not be strobed out until the first key is released. This feature prevents ambiguity of character codes as a result of two keys being depressed in rapid succession. ELECTRICAL SPECI FICATIONS: * Voltage requirements - +5.0 V and -12.0 V * Power consumption - less than 200 mw * Outputs - standard ASCII; 7 bits + strobe * Negative or positive logic output, jumper selectable * Output connector - standard 14 pin DIP IC socket * Three modes - normal, shitt & control MECHANICAL FEATURES: * Size - 12%" x 6%" x 2y/' * High grade glass epoxy PC board * Keyboard ROM SMC KR2376 40 pin MaS * Electronic shift lock, not mechanical * Keyswitches one integral assembly, not individual keys * Switches have four-finger phosphor bronze contacts with gold inlay * Keycaps are 2-shot high strength ABS plastic These keyboards are available off the shelf in two forms - fully assembled and unconditionally warranteed against defects in manufacture or materials for a full ninety days, or in the more economical kit version. Kit parts are fully warranteed against defects in manufacture or materials for a full ninety days. In either version, full instructions are supplied for operation, including specifications and data sheets. In the kit version, complete instructions are supplied for the assembly process. A reasonably competent technician can completely assemble and test this keyboard in one evening. All parts needed are included. INTRODUCTORY PRICES Factory assembled - $74.95 ppd. Complete kit, w/instructions - $64.95 ppd. Pl ease add $ 1.00 handling per order. Minimum order - $5.00 'S,'l\ ~ JJl~ ]"J Irl D1~ ] J J'{ nDIn Pj) 1] Y 360 Merrimack St., Lawrence, Mass. 01843 o (Telephone orders: 617-688-0751 603-434-4644) 81 WORDS FROM A READER Your answer to a reader's question on the difference between a "bit" and a "byte" and a "word" was pretty good, except for the definition of a word. The difference is made NEVER YOU MIND more apparent if we look at the evolution of computers. Early, so-called first generation machines generally performed arithmetic operations only in accumulators, which were of a fixed OCCUPANT bit length. This length was called a word. BOX BYTE Since all operations were done in accumula PETERBOROUGH NH 03458 tors, each storage address usually had the same bit length, so a word was also the number of bits obtained in one storage reference. I n the second generation, systems were classified as either business or scientific. The scientific machines generally used binary arithmetic, performed in accumulators as before. Business systems, however, did not TASTY BUT NOT FILLING have accumulators, but used storage-to· storage arithmetic. In this system, the con A friend of mine showed me the first tents of two storage locations were input to three issues of your new magazine. I found the ALU, and the ALU output was stored in them extremely tasty but not at all filling; one of those locations. These machines were please send more BYTEs as soon as possible! of variable word length, in that a non-data (I have sent my subscription order in.) bit in each storage location was used to mark I have just one "bit" of criticism: Please the end of a word. Since most of these adopt some designations for end-of-article, machines used 6 data bits and each of the 64 continued-on-next-page, and continued-on bit combinations had an assigned graphic, page-n! Their use is not essential, but my each storage location was usually referred to ETP (English Text Processor) has become as a character. used to finding them (it's a heuristic routine, The IBM 360 series was the first of the you see) and often wastes considerable time third generation, and was designed to be when they're not there. general purpose; that is, either scientific Possibilities include the IBM end-of-file (binary) or business (decimal). Its general Once that happy time code, /*, for end-of-article, or the ASCII purpose registers (which could be us ed as comes to the ham, linking abbreviations ETX (end of text) and FF binary accumulators or index registers or home brew computer (form feed) for end-of-article and go-to memory address registers) were 32 bits long, terminals to their Teletype next-page, respectively. And FF nn could be so this was called a word. The floating point set-ups will combine two used for go-to-page-nn. Alternatively, some accumulators were 64 bits, or a double common notations from assembly languages word. Thus the binary arithmetic instruc of the most fascinating could be used: END, BR *+1 (go to next tions could obtain, in one storage reference, hobbies ever conceived by page), and BR nn (go to page nn); but on either a double word, a word, or a half word the mi nds of men. second thought, these would probably not (16 bits). Decimal arithmetic was performed be as easily recognized by as many people as storage-to-storage, with the instruction con the ASCII symbols. taining the length of each operand. Since the Hope to see your next issue in my term word was used to refer to the register mailbox. Meanwhile, I'm going to try to (accumulator) length, a new term was persuade the proprietors of my college book needed to refer to the number of bits store to carry BYTE. Wish me luck! contained at any single storage address; IBM chose the term byte, and in the 360 series a Jamie E. Hanrahan byte was 8 bits. Fullerton CA In most micros to date, the number of bits at one storage address (a byte) is the Regarding end of file marks, you should same as the length of the accumulator notice by now that articles in BYTE's latest (word), so the terms are interchangable, issues are terminated by a typeset ". ". whether it is 8, 12, or 16 bits. But who We've considered other things ranging from knows what the future will bring? an "EOF" to an END statement. This convention of the black square is simple and R. S. Downs effective, so it became the obvious choice. Raleigh NC 82 OSCI LLOSCOPE GRAPH ICS Now that you've got your computer, sit INTERFACE down and share a byte with a friend. TRI·TEK Acoustic Couplers and Data Modems can get your system on speaking The Oscilloscope Graphics Interface in terms with your buddies' systems for the the October 1975 BYTE is a useful addition price of a phone call. to any microcomputer system. However, if Trade programs, get extra computing power, combine memory capacity or play computer the display ever got really busy, it looks like games across town or across the country - the screen would be a mess. This is due to anywhere you can get to a phone. the fact that when a Set X or Set Y is us ed, If you don't have a computer, turn a the scan continues from that point on down TELETYPE or video display into a remote terminal which will talk to any time·share· the screen. Rapid access to the 2102's, as in rnIT1f~ system found in most large cities or at any sort of "moving picture" presentation, GET YOUR universities. Form your own club, make one computer and share it over the phone lines would never let the trace get down the with your terminal. screen very far. TOGETHER Hundreds of these quality units are in service in industry and business; A simple modification which would alle and TRI ·TEK is now making them available to the small system users in viate the situation would be to have two factory·assembled or kit form. counters feeding the 2102 address lines, one Models avai lable to do your job in TTY, RS232 or DAA, Bell 130. free running at 100 kHz all the time, and the Write for data sheets or use the reader service sheet. other under program control. With three 12 BIT MICRO PROCESSOR CHIP- state buffers (i.e., 8097's), the memory write IM6100 12 bit CPU recognizes POPB/E, Mp·12 and 0·112 Instruction set. FEATURES: silicon gate CMOS, single supply, or chip clock, power·on of new information would gate only the initialize. All interface'control signals produced in CPU. desired address to the 2102's, after which DMA, interrupt, dedicated control panel, directlindirectl auto indexed MEM addressing...... 60.00 the other address (from the 100 kH z TRANSPARENT CONTROL PANEL CHIPS- counters) would again be applied to the Allows IM6100 to free itself of control panel supervision. Control panel functions can be increased simply by adding additional control panel RAM, 2102's. Thus the scan would pick up shortly easing the main memory useage. after the point where it left off. IM5603 P ROM/IM5501 RAM set ...... 21 .00 For readers with an infrequent screen SET OF DATA FOR IM6100 SYSTEM ...... 4 .00 update, this is not necessary, but for those with fast processors doing frequent display Send stamp for ou r tRI-tEk, Inc modification, this approach should work fl yers of new and 6522 N 43rd Avenue su rp Ius el ectronic 'f: nicely. components. W Glendale AZ 85301 Roger Frank Englewood CO You are right, Roger, and the hardware modification you propose will correct the situation. Another way to avoid running into that problem is to use appropriate software: Simply, do full screen updates when changes are desired. THOUGHTS ON TELETYPE You have asked for comments from BYTE subscribers about themselves, and Super-Versatile™ anything els e that may come to mind, and building blocks for experimental circuits here are my thoughts on what I had hoped Universal.l0" matrices of Create custom breadboards in minutes solderless, plug-in tie points with these new instant-mount strips. for and anticipate in your magaz ine. DISTRIBUTION STRIP (top) contains First off, I am a ham, W2ZPW, for some For all DIP's and discretes 2 continuous buses of 12 connected 4- with leads to .032" dia. tie-point terminals. Size: 6.5" by .35". 26 years . That automatically signifies a Interconnect with any solid TERMINAL STRIP contains 128 5-tie General class ticket or better, and General wire up to No. 20 A .W.G. point terminals, holds up to nine 14-pin DIP's. Size: 6.5" by 1.36". Integral, class it is. I am not interested in any high er Nickel-silver terminals non-shorting, instant-mounting back class of Iic ens e for a very good reason . I am ing permits quick build-up of special ORDER BY PART NUMBER breadboards using any mix of strips. entirely deaf. Any additional frequencies 9232n distribution strip ... $2.50 earned with a higher class of license would 923261 terminal strip .... $12.50 Other models available. require hearing for phone or CW (Con We honor M.C. and B.A.C. charges. Add_ SHIPPING/HANDLING C.O.D. tinuous Wave or Morse code for anyone who Add sales tax on OH and CA orders. fees from Up to $10.00 $1.00 S .70 IF.O.B. Painesville on company P.O.'s.1 this chart. ;~?o~~~O~~5000 i : ~ : ~ just immigrated from the Moon) . Dealer inquiries invited My sole interest in ham radio is in Teletype. Since computer technology runs closely parallel, in many ways, with radio 83 frequency communications, there is no As soon as the FCC removes the restric doubt in my mind but that a goodly tion against ASCII coding, a magazi ne such proportion of articl es to come will be as BYTE will then become the obvious slanted toward the amateur radio enthusiast. vehicle for guiding both amateur radio and Considering this possibility it is certainly not computer enthusiasts to combine their too much to hope for to ultimately see a hobbies for the greatest enj oy ment im ag in simple and ine xpensive commercial ASCII able. The possibilities are endless and limited to-Baudot converter that could read il y be onl y by the imagination. used to actuate the widely used Baudot coded amateur Teletype equi pment. Mack O. Santer Brooklyn NY Use of ASCII code is being pondered and will no doubt soon be written into FCC It looks like there is plenty of possibility reg ulations. But eve n so, those amateurs who for the synthesis of amateur radio and have RTTY using five leve l Baudot equip computer activities. It will be interesting to ment will mostly continue to do so because see just what people actually do with this it is in virtual universal use. It is my novel application of computers. BYTE will considered opinion that ASCII will take hold report on developments in the radio/com to a greater degree than 100 WPM Baudot puter field as they occur. did, but by mea ns of soo n to be devised converters (of a simple and inexpensive nature, it is hoped) , switching from Baudot to ASCII, and bac k aga in, will become virtually universal. Once that happy time comes to the ham, QUESTIONS - linking home brew computer terminals to STAR TREK, SURPLUS their Teletype set-ups will co mbin e two of CHIPS the most fascinating hobbi es ever co nceived by the minds of men (and women). It th en In the first three issues of BYTE, which becomes possible to visualize a means of are just what the doctor ordered, you've communi cation co mbining ca bl e and radio. mentioned the ga me of Star Trek a number Where more than one mini-co mputer system of times in your columns. I am a Star Trek is linked by way of telephone lines it will freak with an IBM 1130 at my disposal. Is become a simple matter to "patch" the there any way of obtaining a Star Trek phone line into a radi o station and rebroad program written in Fortran IV or other cast the computer output to form input to information on the subject? another computer repatched back into a In the near future, will any co mp ani es be phone system elsewhere at a distant point. It marketing a 16 bit computer utilizing ope ns entirely new vistas that may take a bit National's IMP-16 CPU chip? of deep thinking to eve n visua li ze at this Wh at companies carry used or surplus point. The possibilities are so broad in scope Teletype machines in worki ng condition at that I hate to eve n begin to enum erate them. reasonabl e prices? Perhaps your magazine can do a series on the surplus market place. In view of the FCC restriction made up on In the first issue you published a review hams to use onl y five leve l Baudot code, of the RGS 008A computer by James most of the amateur eq uipment in current Hoge nson. I found this very informative and use is American made Teletype Corporation am looki ng forward to more such reviews, eq uipment. Some mod el 14, mostly tape perhaps on the Altair 8800 or SWTPC's new gear, is used. Model 15 printers an d the Motorol a based 6800 computer system. companion mode l 19 sets combine model 14 and 15 to form a co mp osite set that will Look in g forward to more fantastic iss ues ei th er produce co ded tape for transmission of BYTE. (but not be received from on the air) or Richard Wexler print out on roll s copy that is receiv ed or Texarkana TX sent. The model 15 printers are often obtain abl e for as low as $25 and rarely hi gher than $100 for the model 19. There is a BASIC version of Star Trel? The ultimate in Baud ot equ ipment at called Space War listed in complete detail in present is the model 28. Obsolete as they 101 BASIC Games, published by DEC in may be where computers are concerned, Maynard MA. See the boo/? review in this they are hi ghl y pri ze d for ham use. There are issue. The closest product to an IMP-76 yet few model 33 and 35 Teletype machines available is the National PA CE chip, its LSI amongst amateu rs but since they are single-chip successor. designed for ASCII use they require some mea ns of conversion to Baudot coding. Continued on page 86 84 ~ % OFF ON ORDERS OVER $~O.OO 10% OFF ON ORDERS OVER $100.00 1 ~ % OFF ON ORDERS OVER $2~0.00 JANUARY SPECIALS TTL DIGITAL MEMORIES CLOCK CHIPS 7451 .17 74154 1.25 7447 BCD to 7 seg. decoder drvr. $ .69 2102 $2.65 5311 $3.95 7400 $ .14 7453 .17 74155 1.07 7483 4 bit binary full adder .59 2102-1 2.75 5312 2.95 7401 .16 7454 .17 74156 1.07 7490 Decade counter .45 2102-2 2.75 5314 3.95 7402 .15 7460 .17 74157 .99 74151 8 channel multiplexer .59 82S23 3.25 5316 4.15 7403 .16 7464 .35 74158 1.79 74153 Dual 4 input multiplexer .79 F93410 CALCULATOR CHIPS 7404 .19 7465 .35 74160 1.39 74180 Parity generator checker .79 256 bit RAM 2.19 5005 $1.69 7405 .19 7470 .30 74161 1.25 74193 Binary up/ down counter .99 7406 .35 7472 .30 74162 1.49 9602 Dual one shot .69 8038 FUNCTION GENERATOR 7407 .35 7473 .35 74163 1.39 75COO Quad 2 input NAND gate (CMOS) .12 7408 .18 7474 .35 74164 1.59 Voltage controlled oscillator - sine, square, triangular 7409 .19 7475 .57 74165 1.59 output. 16 pin DIP with data $3.95 741 0 .16 7476 .39 74166 1.49 LINEAR 7001 CLOCK CHIP 7411 .25 7483 .79 74170 2.30 301 Hi perf op amp mDiP .25 4-6 digit, 12-24 hr. alarm, timer and date circuits - with 7413 .55 7485 1.10 74173 1.49 339 Quad comparato r DIP 1.29 data...... $6.95 7416 .35 7486 .40 74174 1.62 320T 5V neg. V reg. 5V 1.39 7417 .35 7489 2.48 74175 1.39 320T 12V neg. V reg. 12V 1.39 DVM CHIP 4';' DIGIT 7420 .16 7490 .59 74176 .89 340T 12V neg. V reg. 5V 1.39 MM5330 - P channel device provides alilogicfor 4Y:z digit 7422 .26 7491 .97 74177 .84 340T 15V pas. V reg. 15V 1.39 volt meter. 16 pin DIP with data ...... $14.95 7423 .29 7492 .71 74180 .90 7425 .27 7493 .60 74181 2.98 7426 .26 7494 .94 74182 .79 7427 .29 7495 .79 74184 2.29 Data sheets on request. With order add 7430 .20 74% .79 74185 2.29 $.30 for items less than $1 .00 ea. 7432 .23 74100 1.30 74187 5.95 7437 .35 74105 .44 74190 1.35 PUL.TRtJN V.I.P. QUARTZ REGULATED 7438 .35 74107 .40 74191 1.35 7440 .17 74121 .42 74192 1.25 LED WATCH 7441 .98 74122 .45 74193 1.19 7442 .77 74123 .85 74194 1.25 7443 .87 74125 .54 74195 .89 MEN's 5 function - hours, minutes, month, LINEAR CIRCUITS 7444 .87 74126 .63 74196 1.25 day and seconds. 300 Pos V Reg (super 723) T0-5 S .71 7445 .89 74141 1.04 74197 .89 latest slim-line design (pro •• W ' thick) 301 Hi Perf Op Amp mDIP T0-5 .29 7446 .93 74145 1.04 74198 1.79 Four year calendar - requires setting only 302 Volt follower T0-5 .53 7447 .89 74150 .97 74199 1.79 on February 29th. 304 Neg V Reg T0-5 .80 7448 1.04 74151 .79 74200 5.90 305 Pos V Reg T0-5 .71 One year warranty against all defecls in 307 Op AMP (super 741) mDIP T0-5 .26 7450 .17 74153 .99 material and workmanship. 308 Mciro Pwr Op Amp mDiP T0-5 .89 Built-in phototransistor adjusts intensity of 309K 5V lA regulator TO-3 1.35 LOW POWER TTL 310 V Follower Op Amp mDIP 1.07 display. 311 Hi perl V Comp mDIP T0-5 .95 74100 S .25 741 51 S .29 75 190 Sl.49 Gold tone - with adjustable mesh strap. 319 Hi Speed Dual Comp DIP 1.13 74 102 .25 74 155 .33 74191 1.45 320 Neg Reg 5.2, 12, 15 T0-3 1.19 74L03 .2 5 74171 .25 74193 1.69 322 Precision Timer DIP 1.70 74104 .25 74 172 .39 74195 1.69 324 Quad Op Amp DIP 1.52 74106 .25 74173 .49 74198 2.79 $99.50 339 Quad Comparator DIP 1.58 74110 .2.i 74174 .49 74 L1 64 2.79 340K Pos V reg (5V, 6V, 8V, 12V, 74120 .33 74 178 .79 74 L16 5 2.79 +$1.50 Shipping 15V, 18V, 24V) T0-3 1.69 74LJO .33 74185 1.25 340T Pos V reg 15V, 6V, 8V, 12V. 74141 1.49 74186 .69 & Handling 15V. 18V, 24V) T0-220 1.49 Usual 10% Discount 372 AF-IF Strip detector DIP 2.93 373 AM/ FM/ SSB 51rip DIP .53 Applies 376 Pos V Reg mDIP 2.42 HIGH SPEED TTL 377 2w Stereo amp DIP 1.16 74HOO .25 74H21 $ .25 74H55 S .25 380 2w Audio Amp DIP 1.13 74HOl .25 74 H22 .25 74H60 .25 380·8 .6w Audio Amp mDIP 1.52 74H04 .25 74 H30 .25 74H61 .25 381 Lo Noise Dual preamp DIP 1.52 382 Lo Noise Dual preamp DIP .71 74H08 .25 74H40 .25 74H62 .25 LED '. 74HIO .25 74HSO .25 74H72 .39 5SO Prec V Res DIP .89 MV10B Red TO 18 S .22 MEMORtES Timer mDIP .89 74Hl1 .25 74H 52 .25 74 H74 .39 555 MVSO Axial leads .1 8 556A Dual 555 Timer DIP 1.49 74 H20 .25 74 H53 .25 74H76 .49 1101 256 bit RAM MOS S 1.SO MV5020 Jumbo Vis. Re d 560 Phase Loclled Loop DIP 2.48 1103 1024 bil RAM MOS 3.95 (Red Dome) .22 S62 Phase Locked Loop DIP 2.48 1702A 2048 bit static PROM Jumbo Vis. Red Phase Loded Loop DIP TO-5 2.38 8000 SERIES UVeras. 17.95 565 (Clear Dome) .22 566 Function Cen mDIP T0-5 2.25 2102-2 1024 bit slatic RAM 4.25 80!;t1 S .53 8214 S1.49 8811 S .59 ME4 Infra red diff. dome .54 567 Tone Decoder mDIP 2.66 5203 2048 bit UV eras PROM 17.95 8092 .53 8220 1.49 8812 .89 MANI Red 7 seg .. 270" 2.19 709 Operational AMP TO-5 or DIP .26 5260 1024 bit RAM 2.49 8095 1.25 8230 2.19 6822 2.19 MAN2 Red alpha nurn .32" 4.39 710 Hi Speed Voll Comp DIP .35 5261 1024 bit RAM 2.69 8121 .Btl 8520 1.16 8830 2.19 MAN4 Red 7 seg.. 190" 1.95 711 Dual Difference Com par DIP .26 5262 2048 bit RAM 5.95 812] 1.43 8551 1.39 88]1 2.19 MANS Green 7 seg ..27 0" 3.45 723 V Reg DIP .62 7489 64 bit ROM TIL 2.48 8130 1.97 8552 2. 19 8836 .25 MAN6 .6" high solid seg. 4.25 739 Dual Hi Perf Op Amp DIP 1.07 8223 Programmable ROM 3.69 8200 2.33 8554 2. 19 8880 1.19 MAN7 Red 7 seg.. 2 70" 1.1 9 741 Comp Op Amp mDlP TO-5 .32 74200 256 bit RAM tri-state 5.90 8210 2.79 8810 .69 8263 5.79 MAN3 Red 7 seg .. 127" 747 741 Dual Op Amp DIP or T0-5 .71 8267 2.59 straight pins .29 748 Fre q Adj 741 mDIP .35 MAN8 Yellow 7 seg . . 270" 3.45 1304 FM Mulpx Siereo Demod DIP 1.07 9000 SERIES MAN66 .6 " high spaced seg. 3.75 1307 FM Mulpx Ste reo Demod DIP .74 MCT2 Opto-iso transistor .61 1458 Dual Comp Op Amp mDIP .62 9002 S .35 9309 S .79 9601 $ .89 CALCULATOR & 1800 Stereo multiplexer DIP 2.48 9301 1.03 9] 12 .79 CLOCK CHIPS 9602 .79 ...------..... lH2111 Dual LM 211 V Comp DIP 1.70 5001 12 DIG 4 funcl fix dec S2.49 MULTIPLE DISPLAYS Quad Amplifier DIP .35 5002 s.ame as 5001 exc 3900 NSN33 3 digit .12" red led 12 pin 7524 Core Mem Sense AMPL DIP .71 btry power 2.79 fits IC skt . S1.79 8038 Voltage conlr. osc. DIP 4.25 5005 12 DIG 4 fuct w/ mem 2.99 HP45082 5 digit .11 led magn. lens 8864 9 DIG Led Cath Dr", DIP 2.25 CMOS 40Tf)A .56 40S0A .59 MM5725 8 DIG 4 funct chain & dec 1.98 7405 com. calh 3.49 75150 Dual Une Driver DIP 1.75 ",OOOA .26 4017A 1.19 4066A .89 MM5736 18 pin 6 DIG 4 funct 4.45 HP5082 4 digit .11 LED magn. 75451 Dual Perepheral Driver mDIP .35 4001A .25 ·W20A 1.49 4068A .44 MM5738 8 DIG 5 funct k & mem 5.35 7414 le ns comm. cath. ].25 75452 Dual Peripheral Driver mDIP .35 4002A .25 402 1A 1.39 4069A .44 MM5739 9 DIG 4 funcl (btry sur) 5.35 FNA37 9 digil 7 seg led RH 75453 (351) Dual Periph Driver mDiP .35 4006A 1.35 4022A 1.10 4071A .26 MM5311 28 pin BCD 6 dig mux 4.45 dec dr. magn. lens 4.95 75491 Quad Seq Driver for LEO DIP .71 ",OO7A .26 4023A .25 4072A .35 MM5312 24 pin 1 pp5 BCD SP-425-09 9 digit .25" neon direct 4008A 1.79 4024A .89 40nA .39 75492 He. Digit driver DIP .80 interface with MOS/ LSI , 4 dig mux 3.95 4009A .57 4025A .25 4075A .39 1SO VDC, 7 seg. 1. 79 MM5313 28 pin 1 pps BCD ",OIOA .54 4027A .59 4078A .39 6 dig mux 4.45 401lA .29 4028A .98 4081A .26 MMS314 24 pin 6 dig mux 4.45 4012A .25 4030A .44 4082A .35 MM5316 40 pin alarm 4 dig 5.39 4013A .45 4035A 1. 27 4528A 1.60 SHIFT REGISTERS 4014A 1.49 4042A 1.47 4585A 2.10 401 5A 1.49 4049A .59 MM5013 1024 bit accum. dynamic mDlP SI .75 MM5016 500/512 bit dynamic mDIP 1.59 Salis faction guaranteed. Shipmenl will be made via first class mail in U.S., Canada and 74COO ) .22 74C74 SI.04 74C162 $2.9] SL5-4025 QUAD 25 bit 1.29 Mexico wilhin 5 days from receipl of order. Add $.50 10 cover shipping and handling 74C02 .26 74C 76 1.34 74C16] 2.66 for orders under $25.00. Minimum order $5.00. California residenls add sales lax. 74C04 .44 74C 107 1.13 74C164 2.66 74C08 .68 74CI 51 2.61 74C l 73 2.61 INTERNATIONAL ELECTRONICS UNLIMITED HCIO .35 74CI54 3.15 74C19S 2.66 DTL 74C1 57 1.76 80C95 1.]5 74e20 .35 930 S .15 937 .15 949 .15 .a. P.O. BOX 17081 MONTEREY, CA. 93940 USA 74C160 2.48 80C97 1. 13 74C42 1.61 932 .15 944 .15 962 .15 74C73 1.04 74C161 2.93 --.-. PHONE (408) 659-3171 936 .15 946 .15 963 .1 5 I ..... j .; .. : NYBBLE ROLLING HIS OWN At long last one of the thi ngs that I have I am particularly encouraged to see a wondered about all my life has bee n defined. magazine of this type published; most of the I refer to your answer to Stephen Holl and's other publications available either assume letter on page 84 of issue 3. You define a the bac kground of an electrical engineer or nybble as half of a byte. I am a fisherman computer science theoretician, or assume no and had never before known exactly what a background at all. I've always wanted a nybble was. Now will you define stryke? computer of my own, and when the All kidding aside, I enjoy the magazine "Mark-8" project came along, I jumped at greatly. I am a nuts and bolts hardware type the chance to get one. I have it almost with a good technical background, first finished, but have had ~o me problems in phone and amateur extra, and enjoy all the obtaining simple items like a decent power articles. The ones on programming are above supply at a reasonable price (not trusting my me yet. No experience in that area. So, on electrical theory enough to build my own), page 88 I give them a ll 10 (shades of or attractive paddle switches for a front Analog). panel. Fortunately I have not been working Keep up the good work with a balanced alone, having a partner building another magazine that will appeal to all of us for we Mark-8 along with me; we order our com all need to know something about each ponents together and take advantage of other's areas. quantity discounts. Your magazine kept my wheels turning Roy W. Dancy into the early hours of the morning, Dothan AL especially the material on graphics displ ay devices. The 8008 is cheap and that is an A stryke is what happens when lightning important consideration for any one on a hits a computer. It gets all shal?en up and grad student's budget. Perhaps in the future, refuses to work. the other chips and kits will come down in price and us poor fol ks wi II get a ch ance to play wi th the other stuff. Robert Jones Washington DC A well done Spacewar SPACEWAR, game is one of the most ANYONE? - PS, Any chances of an organized project interesting strategy and to get a hardware text editor, loader, assem hand-eye coordination Let me first add a word of ap prec iation bler for 8008 systems? tests ever invented. to all the others you have received. BYTE is a great magazine. Be sure and send me my It is good to hear that you are getting a renewal notice when it comes due . computer up and running, Robert. An 8008 The other item I would like to bring up is will certainly serve you faithfully and Spacewar. This is a game that was played on reliably once you get your system up, conventional computers 5 years ago. How running and debugged. I may be critical of much memory do es it take? Do you know the 8008 at times because it is a machine where I could get a copy of a program of with which I have intimate familiarity: my one of its versions 7 first home brew computer learning experience was an 8008. Aside from the Stewart Shelton relatively slow speed of an 8008, it is quite Madison WV capable of executing all the typical home brew computer person's requirements. Thank you Stewart. We cannot reel off a definite answer on memory requirements for Spacewar, but do believe a reasonably com petent Spacewar application is within the HOUSEKEEPING COMPUTER realm of the home brew computer tech nology as it stands today. We've seen imple My husband just received his first copy, mentations done on minicomputers with less October, of BYTE yesterday, and as usu al I than 32K 76-bit words. When we get some glanced at it as I brought it in . Surprise! An good articles on this application, you'll see article just for me! Most of his magazines them printed in the pages of BYTE. A well don't interest me too much, because their done Spacewar game is one of the most articles are too technical. But Rich ard Gard interesting two-person strategy and hand-eye ner's article was fascinating. We almost coordination tests ever invented. fought over who got to read the magazine. 86 The main reason the article was so interesting to me is that that is almost exactly our story. We have our own com puter (Altair 8800 with 9K of memory), and we have been planning to use it in most of the ways you mentioned. Soon I will be allowed to put my food planning on the computer: recipes, menus, nutritional plan ning, seasonal shopping, etc. I think I'll even key it to alternate speedy meals for days when dinner starts late. Keith has already begun thinking of eventually using it to control our interior environment, which will be very helpful in maintaining proper storage On all models ... simply plug in your conditions for our year's food supply. I obsoletes components and inter think he is eve n planning to use it to play connect with 22-g a. solid ordinary wire. All models accept all selected music throughout our dream house breadboards DIP's, TO-5's and discretes from a central control center to speakers in with leads up to .032" diameter. Multiple buses can easily be linked for power and ground distribution, the various rooms. His original plan was to reset and clock lines, shift command, etc. Bases: gold-anodized alumi deve lop an information retrieval system, to num. Terminals: non-corrosive nickel-silver. Four rubber feet included. reduce the space required in filing. (We have Order ACE Tie DIP No. No. Board Size Price No. Model No. Points Capacity Buses Posts (inches) Each a 4-drawer legal size file cabinet, full, as well 923333 200-K Ikltl 728 8116'51 2 2 4-9/ 16 x 5-9 / 16 $18.95 923332 208 (assem.) 872 8116'51 8 2 4-9 / 16 x 5 -9 / 16 28.95 as many books, notebooks, etc.) And we 923334 201-K (kit) 1032 12 114'51 2 2 4-9 / 16x7 24.95 923331 212 (assam.) 1224 12 114'51 8 2 4-9/ 16 x 7 34.95 have already been having the neighbor kids 923326 218 (essem.) 1760 18114'51 10 2 6-' / 2 x 7-' /8 46.95 923325 227 (assam . ) 2712 27114'51 28 4 8x9-1 / 4 59.95 in playing with the computer. When we get 923324 236 (assam.) 3648 36114'51 36 4 10-1 / 4x9-1 / 4 79.95 the terminal and cassette recorder con We honor M.C. and B.A.C. charges. Add_ SHIPPING/ HANDLING C.O.D. Add sales tax on OH and CA orders. UptoSl0.00 $1.00 $ .70 nected, our only limit will be the sky (or is it fees from $10.01 to $25.00 1.50 .80 IF.O.B. Painesville on company P.O.'s.) this chart. the memory?). Dealer inquiries invited 25.01 to 50.00 2.00 .90 I'm looking forward to hearing more about home computers, and would appre ciate help in programming my food pro grams, as I don't know much of the tech nical aspects. Carol H. Kendall Vernal UT Bulk Memory Microcomputer Audio LOGICAL INERTIA Yes indeed, by all means, instantly enter my subscription to your fabulous, fascin Cassette Interface ating, incredible magazine. My imagination ,f. races at the thought of a Klugeharp. TV o Records and plays back through $ 50~~ typewriters titilate my thoughts. Do it .. . standard TTY interface 83 my check is enclosed. Allow me to share with you a notice o Variable BAUD rate pos ted on the wall of a major com pu ter o Single +5V supply * Unit QuantitY manufacturer I once was associated wi th: o Rate factory set at 300 BAUD for use with inexpensive Today's computers execute instruc audio cassette recorder tions in the sub-microsecond range. This can cause programs to develop Send To: SOUTHWEST 13777 North Central Expwy. considerable logical inertia, making DEVELOPMENT Suite 416 Dallas, Texas 75231 HALTS extremely dangerous, The COMPANY 214-231-2558 following technique is suggested when a HALT is necessary : D Enclosed is check for $83.50. Please send my cassette Stop HALT interface immediately. HALT In case still skidding GOTO Stop D Please send cassette interface C.O.D. Enclosed is my check for $8.50. I will pay postman $80.00 upon delivery. L. E. Staples Name ______San Antonio TX As with all software problems, the solu Address ______tion is a mass of instructions, City ______State _____ Zip _____ 87 BOOK REVIEWS 101 BASIC Computer Games, Digital Equip eating the poisoned piece; the ancient game ment Corporation. Maynard, Mass. $7.50. of GU ESS, where the user tries to guess the number the computer is "thinking of"; HANG, the age-old game of hang-man, with Before you dismiss this as just another of the added "bell and whistle" of drawing the the plethora of BASIC game books, note hung man part-by-part; and TOWER, a game that 707 BASIC Computer Games claims the program that helps the user attempt to solve Because they are simply distinction of being the "first [circa July the old, old puzzle of the Towers of Hanoi, programmed, there are 1973] collection of games all in BASIC," providing a graphic display of each step on endless small games of and "the only collection that contains both the way. a complete listing and a sample run of each chance, games involving There are dozens of standard game game along with a descriptive write-up." out-guessing the computer, playing or sport-simulating programs. For The preface cites the educational val ue of example, in the card game area, we have and venerable "ancient" games as one of the prime motivations for ACEYDU, an acey-deucey game; BLKJ AC, a games, often with modern the book. This is a fact which no one would very comprehensive (Las Vegas rules) black twists thrown in. seriously contest, but which computer jack game; POKER; and the old card game center di rectors seem to overlook as they of WAR. The book also sports baseball, contemplate the hours of wasted computer basketball, bowling, boxing, darts, bull time. Since time on our home systems is fighting, high school and professional foot never wasted, by definition, this shouldn't ball, golf, ice-hockey (against Cornell!), and pose a problem. parachuting games. Board games include Most of the games in the book are bingo, checkers, Go, Monopoly, Nim, and computer simulations of simpl e games of three-dimensional Tic-Tac-Toe (none of chance, sports, "ancient" games, and board which embody much computer intelligence, or card games. And, as the preface adds, very unfortunately). The simulations include few of the games use the innovative capa games of battleship, gunboat, a World War II bilities of the computer "to come up with bombing mission, Can-Am road racing, Civil something new and truly unique." War battles, fur-trading, governing the The authors of this collection have, for ancient land of Sumeria, ruling a modern the most part, put an imaginative or island wisely, successful pizza-delivering, Many of these programs humorous illustration with each game . The A polio capsule landing, lunar lander are over-simplified versions format consists of a short descriptive write maneuvering, space war, and a stock market up of the game, any special language or of the "real" games, due simulation. The gambling games and games computer requirements, a reference to (and of chance are even more numerous. to the dual constraint of sometimes personal notes from) the author, Many of these programs are over-simpli the BASIC language and and a listing of the game, along with sample fied versions of the "real" games, due to the generally limited computer runs. dual constraint of the BASIC language and resources, but this makes Because they are simply programmed, general ly limi ted computer resources, but them even more attractive there are endless small games of chance, this makes them even more attractive for the for the microcomputer games involving out-guessing the computer, microcomputer user. A few of the games are user. and venerable "ancient" games, often with quite comprehensive and thus rather large: modern twists thrown in . For example, blackjack, pro football, Can-Am racing, there's AWARI, an ancient game of rotating lunar landing, and space war (which is really beans in a pit; BAGLES, a 3-digit number a complete Star Trek simulation). guessing game that teaches simple logic; 707 BASIC Computer Games includes a BUG, a dice-rolling game that draws a bug few novelty and scientific programs such as part-by-part; CHOMP, involving eating a BANNER, which prints large letters on computeri ze d cookie, whil e trying to avoid standard terminals in a banner-I i ke fashion, 88 W~~~~~~~~~~~~~~~~~~~~~~~~~M~~~~~~~M~~~~~ S'IIi S. D. SALES CO. From a close out ofVERNIER metal detector DIAL manufacturer. '/2 !-... Turn, 8 to 1 ratio. Internal stops easily removed to make ~ ~ 6 Digit Digital Clock Kit unit multi-turn. ~ ~ M- .. We wanted our word to mean something to you. When _ we first introduced our clock we used such words as ..~ S. D. presents the MAN-64 by Monsanto - 40 ~_ ~ " impossible", "unbelievable bargain", " prime qual- inch character. A ll LED construction - not're- ~ ~ ity", and "unconditional money back guarantee. " We flective bar type, fits 14 pin DIP. Br and new ~ .. anticipated selling several hundred kits. Your response and f actory prime. Left D.P. _ &fl to our clock has been fantastic. Now several thousand $1 .59 ea. 6 for $7 .5 0 ~ ~ kits later, we hear such comments as "outstanding ~ .. va lue", "exceptional service" , " I can ' t believe it ", etc. FAIRCHILD LED READOUTS _ 69c DRIVER" ~ One enthusiastic customer even wrote saying it was FND-70. Common cathode . Rig ht hand RANSISTORS ~ ~ " the best thing since bottled beer." decimal point. .25 inch character. Prime 2N3904 - NPN ~ .. new units. Perfect for clocks, frequency 2N3906 - PNP .. ~ counters , etc. 69c 10 For $6 8 for $1 ~ .. Here's What The Kit Includes: Best Readout Buy in USA! _ ~ 1 - MM5314 National Clock Chip with socket 21021K RAM's - 8 FOR $12.95 ~ ~ 6 - Common Cathode Led Readouts (.25 in. char.) New units by National. We bought a load on a super ~ .. 13 - NPN and PNP Driver Transistors $9 deal, hence this fantastic price. .. ~ 2 - Push Button Switches for time set 95 Units tested for 500NS Speed. ~ ~ 1 - Switch for Time Hold (KIT) FET'S BY TEXAS INSTRUMENTS Qg .. 1 - Filter Cap WITH SPECS. #TIS-75 but with an internal house number. TO-92 ~rA ~ 4 - IN4001 Rectifiers Transformer POSTPAID plastic case. N Channel, Junction type FET. .. ~ 1 - IN914 Diode ~ .. 2 - .01 Disc. Caps $1.50 SPECIAL 5 FOR $1 .. ..~ 9 - Carbon Resistors P.C . BOARD FOR ABOVE FAIRCHILD BIG LED READOUTS 'ill~ ~ $3.00 each A big .50 inch easy to read character. Now available in ~ ~ either common anode or common cathode. Take your ~ ..~ INTEL 1702A 2K ERASEABLE PROM'S $6.95 pick. Super low current drain, only 5 MA per segment ~ .- We tell it like it is. We could have said these were typical. YOUR .. factory new, but here is the straight scoop . We bought FND - 510 Common Anode CHOICE ~ ~ a load of new computer gear that contained a quantity FND - 503 Common Cathode ~ ~ of 1702A's in sockets. We carefully removed the parts, .. ~ verified their quality, and are offering them on one heck H_P_IS BACK! ~ ..~ of a deal. First come, first served. Satisfaction No Rejects or Retests here - You Want ~ ._ guaranteed . Quality? You have it with this popular 0.3" .. L.E.D. by Hewlett Packard. Fits Standard I.C. ~ ~ PROFESSIONAL QUALITY STEREO HEADPHONES Socket. Right hand DP. 'ill ~ Here is the kind of super deal that S. D. is famous for. 5082-7740 - Common Cathode. .$1.25 ~ ,. Treat your ears to a super sound at a super price. Soft 5082-7730-COmmonAnode. ... .$1.25 ~ ~ 6 for $6.00 - .. padded ear cushions, lightweight, fully adjustable ER ~ headband, long coiled cord, wide response. $6 Post 36 ::~V~.~~T~PS. 115VAG 60 HZ. LM324 _ QUAD 741 OP ! ~, Paid - NEW IN ORIGINAL FACTORY BOXES PRI. For power supplies or audio power AMP _ 99c ~ ~ SALE ON CUT LEAD SEMICONDUCTORS amps. Best quality , full y enclosed. $4.95 NE555 _ Timers _ 49c ~ ~ Leads were cut for PCB insertion. Still very useable. 709CH - OP AMPS ~ I N4148 Diode - 40/ $1 2N3904 (House #Transistor) - Signetics , TRI-State He x Buffer. MOS 4 For $1 _ ~ and TTL interface to TRI-State Logic. ~_ ., ial : $1.49. GE SCR C106B1 ~r:. 4 AMP 200PIV. Sensi- ~ ~ 936 DTL BY ITT tive Gate. 59c _ ~ Black with brushed aluminum insert. Medium size, very Prime , house numbered . Hex Inverter M- ~ attractive st Ie. SPECIAL 5 FOR $1 ~ ~ 82S129. ~~~NxE! 'C~i~~:' : R~~Ch faster Ult~~~t~~I~'~:~:eE 3T~'t~~Ep~C:ia~ $1 MOTOROLA PO$~. ~: DARLINGTON " ~ than MOS devices. 50 NS . Tri-stat e FILTER C MJ3001 - NPN - 80 Volts - 10 Amps - ~ ~ outputs. TT L compatib le. Field program- Dual section, 2000 MFD and 1500 MFD HFE 6000 typo To-3 Case. Ideal for ~ .. abl e, and fea tures on ch ip address at 30 WVDC Twist Lock. 79c ea. 3 For $2 power supplies, etc. We include a free -~, _ decoding. Per fect for microprogramming REGULATOR 723 regulator wl schematic fo r power ~ ~ applications . 16 pin DIP. With specs. Like 7805. 5VDC _ 1 AMP output. Has supply with purchase of the MJ3001 ~ .. $2.95 ea. TO-220 plastic power tab _ 99c You get the two key parts fo r a DC ~.:. ~ TEXAS INSTRUMENTS 8 DIGIT for only $1.99. Regular catalog ~ ~ CALCULATOR CHIP TMSO 103NC IN41 MP $1 the MJ3001 is .82 " ~ MOTOROLA NEGATIVE ~ .. VOLTAGE REG ~ ~ MC1463R - Like our 1469R . excePtof uor ~.:." .. negative voltage. Reg . catalog $5. r ~ ~ 5 rice $1.95. " ~ We do not sell junk. Money back ~.:. .. 741C OP AMPS LARGE SIZE LED LAMPS guarantee on every item . WE PAY _ M- Prime , factory tested and marked . Full Similar to MV5024. Prime factory tested POSTAGE. Orders under $10 add 75c " ~ spec on all pa rameters . Not re-test ed, units. We include plastic mounting clips handling. No C.O.D. Texas Res . add 5% ~ _ fun ction al only , units as sold by others. which are very hard to come by. tax. ~ M- 741 CH -TO-58 Lead Metal Can. 31$1 i I ~ - 741CV - 8 Lead Mini Dip. 41$1 MOTOROLA NEG. VOLTAGE REG S D SALES CO ~ K LED R MC1469R . TO-66 9 Lead package . For 3 • • • ~ rA By Litronix . . 65 in ch character . Common TO 30V Outputs. Provides 600 MA direct P.O. BOX 28810 ~ ~ anode. Outperforms SLA-3. perfect for ou tput or more by USing on externa l DALLAS, TEXAS 75228 - ~'liD giant digital clocks. Only 20 MA. per power tran sistor. R ego ca ta1 og $4 ea . Q~ _ segmen t Special $250 ea (Not Class It) With specs . $1 .95 ea. ~ "~~1: MER Rye H R 1ST MAS AND A HAP P Y NEW YEA R ilfnfftmfftr. 89 LIFE, L1FE-2, which is a competitive game are written in "standard" BASIC (where of life, HEXPAWN (see BYTE no. 3). and a "standard" apparently means DEC's children's literature quiz. A few of these BASIC), so some conversion may be games are worth singling out - my favorite necessary for other BASIC systems. I would is a buzzword generator that produces useful emphasize this warning - some of DEC's (?) computer jargon such as "total moni BASIC features used in the games (the file tored mobility," "systematized reciprocal handling procedures, for example) may be programming," "integrated management difficult to convert. options" (surely a useful phrase) and However, it should be clear that 7D7 "parallel digital concept." Another pair of BA SIC Computer Games is really a programs, POETRY and POET, produce "Hacker's Garden of (Computer) Verse," Haiku-like and Edgar Allen Poe-ish verse, and is certainly worth the $7 .50 it costs. For respectively. They're somewhat deter ordering and bulk discount information, ministic, but certainly fun at first. write Digital Equipment Corporation, Soft The preface includes a caveat, warning ware Distribution Center, 146 Main St., any users that the majority of the programs Maynard MA 02154. Man is never satisfied with what he's got - the third section of Microprocessors deals with limitations of microcomputers and how Microprocessors: New Directions for 16-bit unsigned operands in 23 mi cro to push them back a bit. Designers, edited by Edward A. Torrero, seconds. Using only 16 standard SSI and 7975. Hayden Book Company, Rochelle MSI circuits, this CPU addition reduces Park, New jersey. $8.95. multiplication time by a factor of 30 from software, and by a fac tor of 7 from the optional National-supplied multipl y instruc Microprocessors is a paperback collection tion. Other articles include an investigation of reprints, originally published in Electronic of the "microprogrammability" of some Design from 1973 to 1975. Edward A. micros for special applications, construction T orrero has put together a book aimed of a system that allows a conventional mini principally at the desi gn engineer, empha to debug a microsystem, implem entation of sizing the practical aspects of microcom an external push-down stack for the 8008 to puter design. ass ist in interrupt handling, and specifica The first section dea ls with an overview tions for providi ng the clock and drive of the micro's imp act on industry. Represen signals for the 8080, something apparently tative articles are "Focus on Micropro missing from the 8080's application data. cessors," a truly global assessment of the The articles of the fourth and last section current situation and potential of microcom cover an ample range of applications. The puters for the design engineer; and "Smart first is a close-up of a Motorola 6800 CPU Machines in Industrial Electronics," a look used as a controller of a simple drum printer; at micros in num erical control and related the second describes the use of an ACIA equipment. (Asynchronous Communications Adapter) in The second section, " Microcom pu ter a minicomputer context. The last three articles deal with us es of micros in instru For the hobbyist hardware Basics," includes articles on microprocessor selection for various applications, the capa mentation, phase locked loop motor control, expert, the book provides bilities and various techniques of microcom and "intelligent" networks of computers. a fair overview of the puter input and output, the choice between From this (rather exhaustive) list of microcomputer field; for random logic and micros, an analysis of articles, it should be clear that Micropro the person more micro instruction sets, some basics of soft cessors is certainly a useful book for its acquainted with software, ware construction, and an excellent worked intended audience, the electronics des ign it gives a good introduc through example of microprocessor control engineer. It also fills two other important tory look at the field from of traffic lights. This section also features a functions: for the hobbyist hardware expert, it provides a fair overview of the microcom a hardware perspective. detailed look at the internal operation of, and external support required for, the 8008 puter field; for the person more acquainted CPU chip. with software, it gives a good introductory But man is never satisfied with what he's look at the field from a hardware perspec got - the third section of Microprocessors tive, an introduction that I found very deals with limitations of microcomputers useful. and how to push them back a bit. The first article, "Speeding Microcomputer Multipli cation," shows how to build a CPU-comple Chris Ryland mentary multiplication circuit for the 25 Fallen St. IMP-16C that allows multiplication of two Cambridge MA 02138 90 2704 x 4 BIT MEMORY BOARD DATA I NPUT KEYBOARD HOUSi NG This high impact plastic Have you ever loaded a long housing was part of a program into memory, only to famous name programmable have the power fail? Lost the desktop calculator. It is tan, entire program, huh? If so, you has the general appearance know the value of having a non· of a typewriter case, and is volatile magnetic core memory. ideal for many types of compo We have acquired these core uter keyboards. Mounting memory boards, made by center for the keyboard is 15%". 8urroughs. They appear to be The readout space is 15" x 4". ~ 52 x 52 x 4 bits wide (2704 Overall size is 18" x 18%" x 6%". bits x 4), for a total of 10,816 3 Ibs. Will easily house an entire bits. Unfortunately, we don't have data, but for the modest price we TVT.or micrpcomputer. Prepunched -~==~====~~~ are asking they are well worth the effort to figure out. 7%" x 9" x hole In rear for a muffin fan. The opening in the top may vary 1 *". Sh ipping weight 2 Ibs. Less than 1/1 0 cent per bit! the one shown in the drawing. STOCK NO. 85316 Core Memory 80ard $9.95 each, 4/35. STOCK NO. 89176 $3.75 each, 2/7.00 256 X 4 BIT CORE MEMORY BOARD HEA VY DUTY POWER SUPPL Y . - - -! J This power supply is surplus from a maker of . .. computer peripherals. It has outputs of +5v. : \ .. I Another non·volatile magnetic core @ 5 amps, -5v @ 500ma, +12v @ 2.5 amps. ' . . memory board. This one was originally and -12v @ 200ma. All voltages are well . • d made for one of America's largest calcu· filtered and regulated. Ideal for your micro· . .: ill II IIIIIr;. ,iii " " lator manufacturers. It is a complete or mini· computer. All are tested & working. 256 bit x 4 bits wide memory board (1024 bits). Complete with 10% .. x 13%" x 7" high, shipping weight 221bs. core drivers and sensors. 6%" wide x 3*" high, 1 lb. With limited STOCK NO. 85312 $34.95 data. QUANTITY LIMITED. STOCK NO. 85203 $9.95 each ALCO KNOBS FOR EVERY APPLICATION Machined aluminum knobs with 2 setscrews. Clear anod ized KEYTOPS & SWI TCHES finish. Latest distributor price $ .65 to i .05 each. ALCO NO 0 .0. x. HT. DEL TA NO. PRICE TO MAKE YOUR OWN KEYBOARD KS 500A .500" x .625" w / skirt 86176 .40 ea • .10 / 3.50 K 700A .750" x .620" 96177.40 ea. 10/ 3.50 .... K 1250A 1.250" x .750" 86178 .60 ea, 1014.50 ' 2502 AY-5-1013 UART "[,BOARD Brand new, tested, General Instrument AY·5·1013 UART We have a large selection of KE YTOPS and SWI TC H lOS . made bv RAYTHEON CO. The key tops co"," in black . grey and white. (Universal Asynchronous Receiver/Transmitter). This with contrasting legends. The switches mate w i th the tops. and are 40 pin IC is pin compatable with Signetics 2536, T!'s magnetic reed switches . . The followi nSJ combinations are available: TMS6012, SMC COM2502, etc. The UART is the 54 key typewriter set, keys only. black K9276 2.95. 54 key typewriter set. keys only, grey K 9278 ~.95 standard buildin.Q block for para/leI to serial and serial 54 key TTY set. no symbols white K 9 279 2 .95 to parallel conversion, serial communication, etc. A must 54 key TTY set. with symbols white K9282 2 .95 for TVTs, cassette interface, RS·232 interface, etc. 54 key set. keys & switches blac k K 9288 30.00 STOCK NO. B3119 $3.95 each 54 key set. keys & switches grey K9290 30.00 64 TTY set, no symbol. keys 81 Sw. White K9291 30.00 COMPUTER GRADE ELECTROL YTICS 54 TTY set. with symbols. keys & Sw. whiteK9291 30.00 We carry a good selection of capacitors of all types, dipped micas, 11 Key Numeric set. Keys only Black K9283 1.50 ceramic disks, mica trimmers, tantalums, silvered micas, tubulars, 11 Key Numeric set. Keys only Grey K9284 · 1.60 small electrolytics, high voltage, etc. Listed below are a few of our 11 Key Numeric set, Keys only White K92 95 1.50 12 Key numeric set. Keys only white K9286 1.50 large computer grade electrolytic capacitors. VOLT MFD STOCK PRICE 11 Key Num.set. keYI & switches Blac k . K9293 7.00 11 Key Num. set, keys & switchesGrey K9294 7.00 10v 40,000 82026 2.00 each, 6/11.00 11 Key Num. set. keys & switchesWhite K9295 7.00 10v 90,000 82495 3.00 each, 3/8.00 12 Key Num. set, keys 81 switcheswhite K9296 7.50 10v 160,000 82515 3.25 each, 4/12.00 15v 110,000 82352 3.50 each, 3/~.00 Blank key 1 Y, keys wide white K9297A 3 /.25 25v 32,000 82492 3.00 each, 4/10.00 Blank key 2 keys wide white K92978 3 / .25 35v 40,000 82255 3.50 each, 3/9.00 K9297A with switch whitt! K92 9BA 3/ 2 .00 K9297 B with switc h white 50v 10,000 82493 3.25 each; 4/12.00 K92 988 3( 2 .00 75v 6,000 82450 3.50 each, 4/12.00 KR·2376 KEYBOARD ENCODER ROM 200v 500 82345 2 ..50 each, 4/9.00 1458, dual 741 type op·amp. 8 pin mini·DIP. Very versatile. This IC Keyboard Encoder is ideal for use with the above key· STOCK NO. 83112 $1.25 each, 5/5.00 board sets, or with any other keyboard. Made by General Inst., this 40 pin IC features TTL/DTL or MOS compatable outputs, 2 MILLION BIT MEMORY DRUM external parity selection, 2 key roD·over, N·key lockout, self We have one 2 million bit memory drum which was removed from contained oscillator, and static charge protection of all inputs an experimental computer. It was manufactured by General Instru. and outputs. This chip is programmed for ASCII code outputs for 88 keys in the Normal mode, using external Shift operation. ment Co. for Ultrasonic Systems Corp., Mount Laurel, N. J. It is "In the Shift mode, it is programmed for EBCDID outputs. New, G. I. Model MHI2C·I28·189, Serial No. 7816, and U.S.C. Model tested, with data sheets. G.I. number KR.2376-10. 620MDRAI206. It has a maximum access time of 33.4 ms, and a transfer rate in excess of 500K bits/ sec/ track. There are 108 r-_ST_O_C_K_N_O_._B_3_1_1_8 ______---'S...;.9_ .9""5_ea_c_h____ -\ storage tracks, expandable to 128 tracks, with a seperate head for each track. The number of bits/ track = 16,000. For more data, M1568 Clual 15 volt regulator IC. Tracking regulator, 15v phone us and ask for Mel Weiss or Ray Jorgenson. 617·388-4705 @ 100 rna each. 14 pin DIP. STK NO. 84481 $1.50 ea, 4/5.00 S500 MIN IMUM OR DE R $5 .00. I nclude sufficient pos.taga. excell refunded. Send for new 88 page Catalog 15. bigger than aver. __ BANKAMERICARD and MASTERCHARGE • ...... ,,'w. now accepted. minimum charge $16.00. PI.as8 - Incl~de all numbers. Plume ordars !,ccected. Review: The CT -1024 Kit James Hogenson The Southwes t Tech CT-1024 is a key for component placement and two color foil Box 295 board to TV interface which di spl ays 16 pattern diagram . The main board circuit Halstad MN 56548 lines of 32 ASCII characters each on a TV diagram is supplied on a separate 18 inch by screen. The CT-1024 may be ordel-ed with a 24 inch (45.7 cm by 61.0 em) sheet. variety of options facilitating easy interfa ce Documentation for the optional plug-in with any computer. The CT-1024 is a boards is provided with each of those kits. welcome compromise between one line LED Assembly is not difficult, but it is not a displays and commercial CRT or hard copy "one-evening" type of project either. It will terminals. be worth your whil e to take your tim e and Data to be displ ayed is stmed in the form be careful while putting the CT-1024 of ASCII coded characters. The display together. There is a flat charge of $25 if you circuitry scans the memory, converts the have to send your main board in for repair. ASCII codes to 5 by 7 dot matrix charactel's, Getting the CT-1024 adjusted and cali and then generates the video signals brated after assembly is as simple as turning necessary to reproduce th e characters on a four pots. There are no specia l tricks TV screen. involved, and the on ly instrument nee ded is The mai n bo ard holds th e character a VOM . ge n er ator, synchronization and tlml ng The CT-1024 I-equires 5 Vat 2 A, and -5 circuits. This doubl e sided board, meas uring V and - 12 V at 100 mA each. If your 9.5 inches by 12 inches (24.1 cm by 30.5 existing system's power supp ly is unabl e to cm) holds 42 integrated circuits and a few provide this, you can buy the CT-P power other parts. Three cable connectors are supply kit for $15.50; the entire supply mounted on the main board for input, circuit is contained on one small separate output and power supply connections. A board. The PC board, components and trans group of connectms are provided for plug-in former are included in the power supply kit. boards. There is a wide variety of input options The memory board plugs into the main for the CT-1024 al lowing interface with board. The memory uses 2102 type chips to almost anything. Any TTL compatible store 1024 characters. The memory is ASC II input wi ll be accepted. The SWTPC divided into two pages of 512 characters keyboard kit can be connected directly to each. A switch can be us ed to select the the CT-1024 main board. If you do not page, or without a switch, the pages will require data ready control strobes, you can alternate. When one page is fi ll ed, the connect your microcomputer's output display automaticall y selects the other page. directly to the main board input. If this is The main board, memory board, parts for done, however, you must program a time both and a 29 page manu al, constitute the delay between each data transfer. This basic kit se lling for $175. The manu al method will also be error prone if inter includ es step-by-step assemb ly instructions connect cables are more than 2 or 3 feet in for the main bo ard and memory board, length. detai led testi ng and cal i bra ti o n instruc tions, If the CT-1024 is used as a remote five and one half pages of "How it Works," terminal, the ser ial interface kit is an connector diagrams, parts lists, and fo ld outs excell ent option. This kit will al low the 92 LOGIC POWER SUPPLIES New Lambda transistorized, regulated, worth 2 or 3 times our price. 1. (LVEE-5)OV, 5VDC74amp ...... 125.00 2. (LWD - 12) 12 VDC 26.5 amp ...... 100.00 3. (LMB - 5) 5 VDC 3.7 amp ...... 40.00 4. (LMD - 15Y) 15 VDC 9 amp ...... 45.00 SOPHISTICATED LOGIC SUPPLIES By Dressen·Barnes and NJE. Transistorized, finely filtered and regulated. 115 volt input. #41·5S Output 5VDC 6 Amp $25.00 #421 ·32 Output 32VDC 3.3 Amp 12 Ib 20.00 #421-90 Output 90VDC 1.2 Amp 12 Ib 20.00 #NJE 5VDC 34 Amp 351b 75.00 MEMORY SYSTEM $125.00 New memory system by Honeywell, small ... measures only 9x4x 1 inches. 1024 core memory, 1024 words with 8,9,10 bits/word. Random access, with all logic, register, timing, control, core select and sense functions in one package. New, booklet of schematics and data. Looks like a good beginning for a mini-computer. Limited supply on hand. Ship wgt 3 Ibs. #SP-79 ...... $125.00 1,0001lF 15 volt $ .35 2,000 11 F 35 volt 1.00 COMPUTER 2,000 15 .50 12,000 40 2.50 CAPS 1,000 25 .70 3,900 50 2.00 BRAND 3,000 25 1.00 22,000 75 3.25 NEW 1,000 35 .80 CORE MEMORY Another brand new memory, ultra small. Measures only 4 x 4 inches with format on one plane of 32 x 32 x 16 (16,384). Only about 35 units of this on hand. #SP-81 ...... $20.00 SANDERS 720 KEYBOARD ...... $40.00 FREE CA TALOG Please add shipping cost o n above. MESHNA PO Bx 62 E. Lynn Mass. 01904 93 Southwest Tech CT-1024 video terminal . .. built on a homemade base. Row of switches along the top is for extra functions. terminal to communicate via a three wire faster data transfer between the CT-1024 system, phone line, or magnetic tape storage and your microcomputer. The parallel inter system. face board provides the handshaking, The serial interface will convert parallel buffering and timing necessary to transfer data to serial data and will produce not only data properly at high speed in a number of the serial data, but start, stop and parity bits system configurations. The various operating as well. The serial interface will both modes are programmed by jumper wires. transmit and receive, thus making the The versatility of the parallel interface board CT-1024 a complete termi nal. Standard makes the CT-1024 compatible with any speed is 110 baud. Adding optional parts to computer system - from home brew hobby the PC board will provide 150, 300, 600 or systems to large scale commercial systems. 1200 baud. High noise immunity in the parallel inter When the serial interface is used, the face is provided by a special circuit on the keyboard is connected to the serial interface strobe lines and on all inputs from the data board. I n the echo mode, data is transmitted bus. For maximum flexibi lity, all data and to the receiver, but is not displayed on the strobe lines from the 10 bus can be selec . screen until it is transmitted back to the tively inverted by programming jumpers on terminal. Otherwise data is transmitted and the PC board. The keyboard can be directed simultaneously displayed. to just print data on the screen, print data The input and output connections are on the screen and load the data onto the RS-232 compatible and will attach directly output bus, or just load data onto the to most couplers and data sets. To record on output bus. The latter option will allow you or play back from magnetic tape, it will be to have all data echoed back for verification. necessary to build an FSK circuit which is The interface input and output bus lines not included on the serial interface board. can be used separately or parallel for bidirec The serial interface board measuri ng tional systems. To make interfacing even 3.375 inches by 9.5 inches (8.6 cm by 24.1 easier, the data flow control lines can be cm) plugs into the main board. This kit either strobed or operated in a demand/ including thorough documentation sells for response mode. All of these options are $39.95. selected by inserting jumper wires on the PC A parallel interface board is avai lable for board. 94 The para ll el interface boa rd measures 4 Th e c u rsor ge nerati o n circuitry is inches by 9. 5 inches (10.2 em by 24.1 cm) inc luded o n the ma in board. A n opt io nal and plugs in to the main board. Both para ll el cursor cont rol kit will provide a wid er range and se ri al interface boards canno t be used at of controls over the cursor. The manu al t he same ti me. The para ll el interfa ce ki t is cursor contro l kit will prov ide switch pri ced at $22. 95. debo uncing fo r your cho ice of switches. The The CT-1024 produces a video signal use of these swi tches or keys wi II all ow you output whi ch can be viewed on a vid eo to move the cursor up, do wn , left or ri ght. mo nitor or a modifi ed televisio n set. Do n't " Ho me up" will return the curso r to the let the " mo difi ed " scare you away because u pper left corner of t he screen. " Erase to the modi ficatio n is qui te simple. e nd of line" will erase anything bet wee n the I picked up an old tube type junker for cursor and t he end of the line. " Erase to end $1 5. I inserted a 10 pF capacitor as me n of frame" will erase anything betwee n the ti oned in the instructio ns, left o ut the rest, cursor and the lower ri ght corner of the but pl aced a 6.8 kO resi stor and a 180 pF frame. di sc capac itor in parall el between t he The cursor control board plugs into the CT-1024 video o ut put and the TV vid eo mai n board. The cursor contro l swi tches input. I disconnected t he I F stage from the connect via wires to the cursor control grid of the video o utput tu be and connected board . The manu al cursor control kit is the CT-1 024 at that po int. Th e o nl y way to ava il abl e for $11 .50. fi nd out what modi ficatio ns are necessary on If you are not prese ntly in a positio n to your set is to start experimenting. The fork o ut the bill s for a good Teletype, jo in telev ision modi ficati o ns necessary will va ry t he club. And get a CT-1 024. Or for th ose of from one set to the next. you who have a Teletype ri g, how about all The CT-1 0 24 includes another con t hose times you rea d a printout o nce, then veni ence: a cursor. The cursor is a little t hrew it away and tried aga in ? A TV blin kin g sq uare di spl ayed o n the screen terminal mi ght be worth the consid eratio n. whic h shows where the next character T he re are lots of other uses fo r a TV entered will be di spl ayed. An opt io nal typewri ter without the compu ter, too. Wh at switch will stop the blin king actio n or bl ank ever your application mi ght be, it seems that out the curso r if des ired. t here are a lot of satisfied CT-1024 use rs. - ALTAIR OWNERS (and users of Altair components) Interface your computer with the outside world! Now an A/ D D/A board for the Altair with : • 1 or 2 analog outputs with 10 bit resolution .8 Analog inputs .4 Digital outputs for control functions • Complete driving software provided • Interfaces numerous inexpensive sensing devices including photocells, thermistors, ultrasonics, and other analog transducers • Drives plotters, CRT's, servos, etc. with 1 D/A$135 kit $175 assembled 2 0/A 's $180 kit $235 assembled Coming January 1-a one-board video interface for the Altair with keyboard interface • Full graphics capability (48x64 matrix) • 16 Iines of 32 characters (64 characters optional on board for use with high resolution TV monitors) • Graphics and text may be mixed on screen • Upper and lower ·case charactures (7x9 font) • Keyboard input port provided $160 kit $230 assembled (Cal residents please add 6% sales tax) POLYMORPHIC SYSTEMS P.O. Box 2207, Goleta, Calif. 93018 95 reader THE service To get further information on the products advertised in this issue of BYTE merely tear, rip, or snip out this advertiser index, QUESTIONNAIRE fill out the data at the bottom of the page, circle the appropriate numbers, and send the works to BYTE, 70 Main St, Peter borough N H 03458. Readers get extra Brownie Points for sending for information since this encourages advertisers to keep BYTE is dedicated to the needs of its readership. using BYTE - which in turn brings you a bigger BYTE. I n order to better gauge matters of editorial policy and content, as well as to give our advertisers some ADVERTISER INDEX "hard facts," we publish this questionnaire_ A1 ACM 6 A2 AP products 67, 73, 83, 87 A3 BYTE's Books 76 What applications do you have in mind for your A4 BYTE Subscription 72 own personal computer system? A5 CMR 74 A6 Continental Specialties 11 A7 Delta Electronics 91 A8 Dutronics 77 A9 Godbout 7 A 10 Hickok 65, 75 A 11 lasis 48,49 A12 IMS 40 A13 Int'I Elec. Un ltd. 85 A14 Intron 67 A15 James 79 A 16 Martin Research 15 Do you presently have a computer? A17 Matrix 8 A 18 Meshna 93 A19 Micro Digital 39 A20 Mikra D 69 A21 MITS CIV,5,37,55 A22 National Multiplex 63 * Pehaco CII, 1 If you own or use a personal computer system, A23 Polymorphics 95 what is its CPU chip or main frame computer A24 Processor Tech 20,21 A25 RGS 17 design? A26 Scelbi 2 A27 S. D . Sales 89 A28 Southwest Development 87 A29 Southwest Tech CIII A30 Sphe~ 23,25 A31 Suntronix 81 A32 Tri Tek 83 Have you had any "on the job" training using A33 Visulex 69 computers as a tool for some purpose? A34 Wave Mate 71 A35 Windjammer 78 *Reader service inquiries not solicited. Correspond directly with company. Reader's Service BYTE JANUARY 1976 Green Publishing Inc Do you know what a computer language is? Would 70 Main St BYTE acquired via you list the computer languages (if any) which you Pet erborough NH 03458 o Subscription know? Please print or type. o Newsstand o Stolen Name Address These questions are a short form "letter to the editor." If you have additional comments, don't City State Zip hesitate to write! Send completed questionnaires to BYTE, Dept. Q, Peterborough NH 03458. Coupon expires in 60 days . . . Feel free to photocopy this page if you wish to keep your BYTE intact. 96 lj[}:{J 0~ [K\O ~@ &[ID@(!1Jlj & aa@)@@@ggljW~§ @@[MJ~(!1Jlj§rm~ It seem s that a great many people that particu lM bl-and of computer_ face cal-ds are only $35_00 for serial came to t he same conclusion that we SwTPC uses the standard Motomla or parallel types_ did he re at SwTPC_ The M6800 is an MCM6830L7 ROM_ This provides Memory expansion wil l be essen o ut stand ing pmcessor and makes a a utomatic loading and a n operating tial if you ever intend to use a resi gl-eat compute r - "BUT" - Not al l system that is compatable w ith othel dent assembler, or highel- level lan computel-s using the M6800 pro system s using the standard wide ly guages such as APL 01- BASIC on cessor a re the sam e_ May we suggest sold Motomla evalu ation set_ As an your system_ Assemblel- pmgrams that you consid e r the following fea ownel- o f am 6800 computer system, typically require a minimum of4,096 tures w hen you make your ch o ic e_ you are eligib le for m embe l-s hip in wO I-ds of memory and h igh el- level the Motol-o la Usel-s Group_ If you languages require even more_ IT IS A COMPLETE jo in you have access to a li bl-al-y of 6800 SYSTEM? p m grams that w ill I-un on your sys HOW DO YOU ENTER You ca nnot get a ll of the advan tem_ Editor and assemblel- pmgl-a ms AND READ DATA? tages of t he 6800 system with only al-e avai labl e directly hom SwTPC. Let's hope it is by way of a TTY, the processor c hip_ Unless the w hole or video tel-minal_ No one with a 6800 family of ch ips is used you can CAN THE SYSTEM BE EXPANDED serious computer appli cation would not poss ibl y get a ll of the vel-siti lity AT A REASONABLE COST? considel- attempting to entel- data and superiol- perfOl-mance that the Some of the limited system s be from a switch and status Iight con system is capable of pmviding_ If fOI in g offel-ed at laWN pI-ices can be sole _ These may be educational, but instance the design does not use the expanded on ly wi th difficulty _ Check they sure aren't practical. Calculator MC6820 pa l- a ll e l and the MC6850 the amount of m e mory that can be keypads and digital readouts are not se ri a l integrated circuits fa I- inte rfac added and at w hat cost_ How m a ny much better_ Thel-e is no substitute ing, you lose the progl-a mmable intel- add itional intedaces ca n be add ed, if for a full a lphanumeric keyboard and face feature th at m akes it so easy to a n y_ How muc h of the above can be term in al system display fOI- serious intel-connect the compute r system run off of the power supply pmvided work_ w it h outside devices such as termi with the system? The SwTPC 6800 na ls, pl-intel-s, disks, etc_ can be expanded up to 16K wO I-ds of Mi/?bug ® is a registered trademarl? of m e mol-y in t he standa rd cabinet and Motorola Inc. IS THE SOFTWARE w ith the powel- supply provided_ It COMPATABLE OR UNIQUE? m ay also be expanded up to eight If the design does not us e the intedace ( I/ O) bOal"ds fO I- ext e rnal "Motmola" Mikbug® ROM, the n the devices by simply plugging in the Computer System softwal-e and programs that will run cards_ Me mory is $ 125_00 for each with serial interface and 2,048 Words on the system al-e pmbably unique to 4,096 word s o f expansion and inter- of memory ______$450_00 o Enclosed is $450 for my SwTPC Computer Kit 0 Send Data O orBAC ______# ______ / o or MC ______Ex Date ______ NAME ADDRESS C I TY STATE Z IP Southwest Technical Products Corp _, Box 32040, San Antonio, Texas 78284 34 22 042 SHLD < HI> notation for mnemonics is that of the Intel 35 23 043 INX H 8080 Microcomputer System Manual 36 24 044 INR H ( M CS-4 72-0275), publ ished in January 37 25 045 DCR H 1975. The table gives all the 8 bit numbers 38 26 046 MVI H< DATA> 39 27 047 DAA from 0 to 255 in decimal, hexadecimal and 40 28 050 Unimplemented octal so the table can also be used as a base 41 29 051 DAD H conversion chart. The following format is 42 2A 052 LHLD < HI> used for the mnemonics: 43 2B 053 DXC H 44 2C 054 INR L One byte instructions are shown in 45 2D 055 DCR L capital letters only, such as MOV C, H 46 2E 056 MVI L< DATA> Two and three byte instructions have 47 2F 057 CMA symbols in angle brackets signifying 48 30 060 Unimplemented 49 31 061 LXI SP < LO >< HI > the additional bytes following the op 50 32 062 STA < LO >< HI > code, such as LOA , 51 33 063 INX SP where is the low order portion, 52 34 064 INR M and is the high order portion of 53 35 065 DCR M 54 36 066 MVI M< DATA> a 16 bit address; and means 55 37 067 STC immediate data; and 118 76 166 HLT 195 C3 303 )MP < LO> 119 77 167 MOV M,ACC 196 C4 304 CNZ < LO> 120 78 170 MOV ACC, B 197 C5 305 PUSH B 121 79 171 MOV ACC,C 198 C6 306 ADI < DATA > 122 7A 172 MOV ACC,D 199 C7 307 RST 0 123 7B 173 MOV ACC, E 200 C8 310 RZ 124 7C 174 MOV ACC, H 201 C9 311 RET 125 7D 175 MOV ACC,L 202 CA 312 )Z < LO> 126 7E 176 MOV ACC,M 203 CB 313 Unimplemented 127 7F 177 MOV ACC,ACC 204 CC 314 CZ < LO>