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May 1978 / Issue #17/ $2.a^[^ 7,50 ! Sfr 8,10 / Ffr 16,0 / UK £2
Ralph Wells 22 PET's Fkst Report Card ... an objective evaluation
Bob Buckman 32 Scope Power! ... a review of Tektronix's Model 922
J. Tom Badgett 36 Trlsls and Tribulations ... one businessman's micro blues
Robert Baker 42 Writing Diagnostic Routines ... while your machine is running
Dan Stogdill 44 Experiments In Software ... serial to parallel conversion
Peter stark 48 Computer Math Primer . .. beginner's introduction to number systems
George Young 54 Kilobaud Klassroom ... No. 10: Bus Traffic Control
John Biankenship 60 Expand Your KIM . . . Part 5: AID interfacing (for joysticl^s!)
Sheila Clarke 64 What's Happening wlth the IBM Selectric?
Dr. Lance A. Leventhal 68 The Top-Down Approach ... with some practical examples Home DiBiasi 76 The North Star Floppy System an ii year-oid can build it!
Stephen Gibson 78 A Simple Mailing System ... a money-making time-saver
Or. Adam Osborne 84 Number Crunching: Two Hardware Solutions
Ken Barbier 90 Money Manipulations ... keep ahead of those cash-flow problems
Richard Roth 94 Strings and Things . . . BASIC conversion techniques
Thomas E Doyle 100 5 Mlnutes or 5 Hours? ... Sorting techniques Compared
Mike Kop 104 Do-lt-Yourself Time-sharing . . . it's easier than you think
Dave Waterman, Dave Lien 110 Cassette Recorder Disaster: Ground Loops
Glen charnock 112 A Different Search Technique ... don't just try it—benchmark it
Publisher's Remarks—4, Editor's Remarlcs—6, Around the Industry—6, TRS-80 Forum—8, Legal/Business Forum—12. KB Club Calendar-13, New Products—14, Booits—16, Letters—17, Kilobaud Classified—114, Contest!—114, Calendar-116 READY for BUSINESS We've got it all together—the cost effectiveness and reliability of our 6800 computer system with a high capacity 1.2 megabyte floppy disk system. . . PLUS—an outstanding new DOS and file management system.
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well. Despite the pressures on The DigKal Group them to deliver systems already being advertised, they've been As a continuing part of my doing their homework and have plan to personally visit as many new systems ready for showing. of the major firms in the micro- Thai's even more remarkable computing industry as possible, 1 when you consider thai they've The snow required by nearby ski areas tends to obscure buildings in recently stopped by The Digital just moved to a new building. New Hampshire. Here's Infolecs plant, somewhere under the snow. Group facility in Denver. The new building should hold They've recently moved to new them for a while. We're so and larger quarters, a move I packed in here at Kilobaud, with virtually fatal flaws. The main Cal Holt stopped by to try and in- envy. Success is almost as diffi- about 70 people jammed into an problem for me was that 1 terest me in buying a PDP8/A to cult to cope with as failure—it's old 40-room house, that those couldn't understand much of take care of the 73/Byte subscrip- just a lot less painful. TDG has modern, spacious offices—some what the salesmen were saying. tion list, bookkeeping, orders, been going through growth prob- not even being used yet—caused They spoke computerese and ap- etc. While Cal was trying to sell lems—and they are many—for- some slight pangs of jealousy. parently had not even a vestigial me on buying a PDP8/A with his tunately, with some success. recollection of English. programming, I was busy selling him on what was happening in One of the reasons for some of In my efforts to learn comput- microcomputers and how I en- the horror stories about early erese, I stumbled through com- The Infolecs Bombshell visioned the future of this new Mils service was the over-success puter hobby newsletters and industry. ofthe 8800Altair. It is almost im- microcomputers. I fell for micro- possible to go through cata- While most of the manufac- computers, hook, Mits line and It took us just five weeks to get strophic growth without ex- turers in the microcomputer field sinker. The newsletters were OK, the first issue of Byte on the periencing severe traumas. The have been concentrating on de- but there really should have been press. This was five weeks of day- "science" of selecting personnel signing and selling hardware, a magazine ... so I started call- and-night work for me, but the is not yet perfect. It takes weeks with just enough software to get ing the editors of the computer- first issue ran 15,000 copies in- or months to find out whether the the hardware to sell, at least one club newsletters to see if I could stead of my original hope of peg is round or square, so the end firm has been taking a different find someone who might be will- 2000. The magazine got off to a result is that you have to train two tack. ing to take a gamble. Hal Cham- good start . . . and so did the berlin wasn't interested. Neither or three people for each job—an Three years ago I looked over microcomputer industry. In was Hal Singer, nor Bob Al- expensive and time-consuming the amount of money 73 Maga- November I managed to lose the brecht. I finally got down to a situation—and all this is happen- zine was spending on outside data magazine ... a story I hope the chap named Helmers who had a ing under great pressure from processing and was amazed to lawyers will eventually allow me newsletter with 300 subscribers frustrated customers. find it was around S2000 a to publish. There are too many and he said, "OK, let's try it." lawsuits going now, so you'll You can imagine the things month. For that amount of On the same day, as I recall, 1 have to wait that one out. that can go wrong as you try to money we could have an in-house came up with the name for the Now, Hash ahead about 2'/: expand from a very small group system that could do what was new magazine: Byte. years to January 1978. Cal Holt —I think Mits had about 15 peo- needed . . . plus much more. I started calling and leaving mes- ple when they announced the Al- sent out word to the computer During the five weeks after the sages for me to get up to see his tair—to ten and 20 times your world that I needed a computer. decisions to get cracking on Byte, plant in Manchester (NH). What original number. Everything that The salesmen flocked in, each I rounded up authors and mailing with CES in Vegas and a ham in- can go wrong will . . . repeatedly. with wondrous descriptions of lists from manufacturers, wrote dustry conference in Aspen, plus TDG has been going through how great his system would be subscription letters, wrote to all a long siege of the fiu in January, this catastrophic growth and and with conspiratorial referenc- of the clubs, put out newsletters, it took me a while. When I finally seems to be emerging reasonably es to competing systems and their etc. It was during this time that made it to Infotecs it was worth the trip. Though I haven't been making a big deal out of it in Kilobaud, I have been discussing the change in the microcomputer market in our Kilobaud Newsletter, which goes to the industry. The fact is that hobby growth has essentially stopped, and most of the growth in the industry has been in sales to small business. Since I had pre- dicted this right from the begin- ning, this has not come as any surprise to me. Here the complete systems are checked out and run in. The whole Infolecs microcomputer system is Being as trapped by the com- thus put together and checked out in a relatively puter hobby as anyone, I have no intention of putting it down. But The CRT and CPU units are tested here as they are small plant in Manchester, New Hampshire. How my rational has been this: The completed. big a plant will they need a year from now? Infotecs has another program they are just releasing. This one is for accountants; it, too, is most comprehensive. Infotecs buys the printer, the keyboard and moni- tor, and makes the microcomput- er board themselves. The whole Publlthtr system sells to the customer Wayne Green Eitcutlve Vice Prttldent through computer stores or other Sherry Smythe dealers for about $18,000, which Editor comes to under $350 per month John Craig Managing Editor on a lease. At that price, no oil John Barry dealer can afford not to get one. Editorial Aailatantt I think Infotecs could sell Oennis Brisson Susan Gross thousands of their oil-dealer sys- Admlnlstrallva AttlslanI tems if they could make them fast Ootty Gibson enough and find dealers with Production Dapanmant Lynn Panciera-Fraser enough backing to be able to han- Craig Brown The CRT, primer and disk thai make up the Infotecs complete system. dle the business. And once they Gayle Cabana The 6100 CPU and memory are in the disk unit. get going on promotion of their Robert Drew Michael Murphy accounting system, who knows Weston ParKer what could happen? Noel R Self Robin M Sloan computer hobby is a very de- men want to spend $12,000 or so Of particular note is the disk Typesetting manding one, requiring a lot of getting the hardware, only to system used by Infotecs. They're Barbara J Lain work and expense for the hobby- have to sit down and write their using a PerSci disk with their own Pauline Halvomk Jennifer Johansson ist who is actually going to under- own programs. Some stores have operating system. The dual disk Marie Walz stand computers and work with been busy writing programs in holds almost two megabytes . . . Ptiotography them. It is, in computerese, a order to facilitate sales, but this is that's right, 946,176 bytes per Bill Heydolph Tedd Clutf nontrivial hobby. awfully expensive. disk. How can they do this? One Associate Editors I felt that this demand on the Imagine my surprise and de- of the tricks is to split the 12-bit Don Alexander words into two characters of six Tim Barry individual would be a limiting light to visit Infotecs and find Sheila Clarke factor. How many people could that they had developed a com- bits each. They have to forego Rich Didday we find who would take the enor- plete microcomputer system of lowercase to do this, but they can Phil Feldman Tom Rugg mous amount of effort required their own, including about the add lowercase if they want to pro- Peter Stark to become serious hobbyists? most comprehensive fuel-oil- vide a word-processing system la- Bookkeeper This had to be a limiting factor, dealer package I could imagine. ter by changing to 12-bit char- Knud E M Keller acters. Marketing whether it came at 100,000 hob- The system is based on the Intersil Sherry Smythe byists or 1,000,000. My predic- 6100 chip, which emulates the The CRT has 24 80-character r^ynthia Gray tions were more in the 100,000 PDP8 . . . thus giving Cal and lines, one of the largest video dis- Circulation Barbara Block range. his programming staff a good plays in the business. The printer Fran Dillon Why did I put the figure that headstart by virtue of their work runs 132-character lines, dot ma- Florence Goldman low? Well, I know how easy it is with the PDP8. The fuel-oil-deal- trix, at 125 lines per minute. Rhonda Ramsey Receptionist to get a ham license as compared er package was mostly written by I talked with some fuel-oil Doni-Anne Jarvis to understanding computers, and Infotecs president Ed Tolson, dealers to see how they felt about Computer Data Control I know how the number of hams and you really have to see it to the Infotecs system. Those al- Judy Waterman Judy Brumaghim has been limited by the effort re- believe how complete it is . . . ready using it are very enthusi- Linda Cafe quired to learn the theory and the right down to providing a print- astic. The owner himself is able to Mary Kinzel code, both trivial compared to out of a customer list showing the do the data input if he wants and Computer Programming Ron Cooke computers. It seemed like a rea- overall profit made on each thus keep control over his busi- Richard Dykema sonable yardstick. customer. ness. The system checks billings Steven Lionel Prlntlr>g Talks with people at computer The program keeps track of against gallons delivered and Michael Potter stores during the last year have each oil truck and its service, warns the operator if things don't William Cering convinced me that my predictions sales, route, driver, etc. It bills add up. It also handles such side- Dwight Perry Mallroom were not far off. Most stores are and sends statements to the cus- lines as diesel oil, gas sales, pro- Theresa Toussaini reporting that sales to hobbyists tomers. It is most complete. Vir- pane sales, furnace cleaning, etc. Bill Barry have not changed seriously dur- tually every oil dealer who has The dealers explained that the Sue Chandler Ethan Perry ing the last year, but that sales to seen the system has signed up for Infotecs system is much cheaper Advertising business have come along from one . . . including two in Peter- Heidi Kulish nothing to about four or five borough. Marcia Stone (continued on pane 20) lla K Willy times those to hobbyists. Those European Distributor stores that are particularly hobby Monika Nedela oriented have been reporting Reader Responsibility Australian Distributor Katharine Thirkell about equal sales between the two UK Distributor factions. You can quickly spot a L P Enterprises hobby store when you walk in One of your responsibilities, as a reader of Kilobaud, is to aid . . . you're ignored unless you and abet the increasing of circulation and advertising, both of H'loOM ft |>uW.th«d moftthl* Err 1001001 WK PwartiOfOugh NH 034M SwMct««.on ralM m in* are a hobbyist. I don't care if you which will bring you the same benefit: a larger and even better US and C«nM« Vi lot on« rM' tX Ic thf»€ fvt m Eufop* Kito«»u
the system comes in—just take a tional Anthem! (Maybe that only look a Photos I and 2. happens with red-blooded com- Actually, that desk is the rea- puter nuts . . . and not everyone.) son why you haven't been hearing too much of the Noval 760 in re- AROUND cent months. They've gone The Gremlin Connection through three suppliers in an at- tempt to get it manufactured to THEINDUSTRY their specs. The hardware and With the problem Noval has software was debugged long ago, been experiencing with the desk, but the desk has kept them from John Craig it's not too farfetched to imagine accepting orders and advertising they might not have survived. the system. However, they are a sister com- ination of the entire industry. The The additional efforts have pany of Gremlin Industries, and The Noval 760: Here it Comes! system is unique, and one of the certainly been worthwhile. You the necessary support has been, big reasons is its "packaging." know, that computer doesn't just and will continue to be, with them Do you remember the Noval Since a picture is worth a thou- pop up out of that desk. Instead, (thank goodness for big sisters!). 760? It first appeared in a full- sand words (I just made that up), it rises up slowly and gently and Gremlin Industries is one of the color ad in the June 1977 issue of I won't strain my typewriter try- brings forth a lump in your throat leading manufacturers of elec- Byte . . . and captured the imag- ing to describe the beautiful desk much as the playing of the Na- tronic arcade games; and the games to run on the machine. veloped some outstanding educa- (That's right, they're the same tional games for grades 2 through games you have to pay a quarter 6. The games make extensive use to play down in your local pub or of graphics and generate a lot of arcade!) Photo 3 illustrates the initiative and competition when system's graphic capabilities in played by two students . . . since one of Noval's most popular the responses are timed and the games. Depth Charge. person with the fastest (and cor- The games, and graphics capa- rect) answer wins. bilities, offered with the 760 are an important part of the overall system approach. The system is a A "People" Compan> home computer, aimed at the hobbyist as well as the lay user. Since most home-systems buyers When I arrived at Noval/ have entertainment applications Gremlin, the first thing to greet in mind, you can appreciate my eyes was an enormous 40-foot Noval's emphasis in this area. banner spread across the front of And . . . you'll be hard pressed the building. "Happy Birthday, to find interactive video games Lonnie Pogue," it proclaimed. 1 such as theirs on any other thought that was neat. I don't Photo /. Is it just another nice-looking desk? No, it's a Noval home systems. think you can appreciate the sig- system ... in its "sleeping"position. I feel that just as much emphasis niTicance of the sign, and how it should be placed on educational reflects the attitude of the com- programs as games—combining pany, until you slop and ask yourself if something like that Noval 760 is an outgrowth of don't we put together a computer them is even better—so 1 was could happen where you work. their efforts in developing system with all this know-how we quite pleased to discover Noval Probably not, right? microprocessor-based video have?" One of the fantastic has done just that. They're in- games. bonuses you get with the pur- volved with the San Diego School They do some other "strange" A few years ago, someone chase of a Noval system is the District in a research program things at Noval that you won't popped up and said, "Hey, why availability of their video arcade called Telemath, and they've de- find at most companies. For ex- ample, they have such a dedicated group that it is not uncommon for individuals to become so en- thusiastic and engrossed in what they're doing that they contribute a lot of personal time to comple- tion of projects. This may not be too hard to understand when you consider, after all, that one of their primary products is games. And the fun and games are cer- tainly in evidence. The Gremlin arcade games are set up every- where . . . and available for the employees to play with in their off time, as you can see in Photos 4, 5 and 6. This "people-oriented" atti- tude is reflected in the design of the Noval 760, also. The system software was designed with the average hobbyist in mind . . . not the professional program-
Photo 2. The 760 . . . "awakened, "and ready for action. Photo 4. The employee lounge at Gremlin.
Photo 6. In the development lab Photo 3. Depth Charge, one of the more popular new games must be tested ... in arcade games available for the Noval 760. Photo 5. It's really rough . . . games everywhere! the name of engineering research. right, in the back, are the various design, you can use an illegal in- interface cards; the video graph- struction mnemonic when assem- ics circuit is situated in front of bling a program. The assembler them on the main board. So much will flag you that it is an error; for the main board—now let's see but if you insist on leaving it in, it what goes with it. will simply be changed to a NOP. The peripherals mounted in the Another nice feature is the listing console consist of a 2500 bps digi- of the Editor commands on the tal Phi-Deck cassette unit, a 12 screen when you call the Editor inch b & w monitor (color op- up for use. tional), a 32-column dot-matrix BASIC is extra. The additional printer and a full ASCII key- cost (under $300) will get you board. 1 don't know if there are Noval BASIC or Noval Extended future plans to add another cas- BASIC installed in PROM . . . sette drive, but a 760 with dual with an added bonus of freeihg minifloppies is on the drawing up the RAM memory it would board. Larger printers can also be normally occupy. Their BASIC ordered, at additional cost. allows full interaction with Prices for the 760 start at $3385 assembly-language programs . . . and include all the hardware (loading and executing), output I've mentioned. and input from individual I/O Photo 7. The heart of the 760 system. The software provided with the ports and (here's the big plus) system consists of a monitor pro- easy-to-use color and b & w gram, a text editor and an assem- graphics commands. There aren't mer. It's forgiving, but not slop- into the three-connector back- bler. 1 found all three easy to use any string-handling functions in py; it's sophisticated, but not plane, is the 760 BASIC in . . . and quite adequate for soft- the "standard" version, but they complicated; and it's capable of PROM. Additional RAM or ware development. Just to give are available in the extended. doing serious home software de- PROM memory segments can be you another example of the hu- velopment—within certain limi- plugged into that bus. On the far man-oriented approach in the 760 (continued on page 20) tations (due to a cassette, rather than disk operating system).
The 760 Ingredienls
The original design was an 8080-based system, which has since been upgraded to a Z-80. Photo 7 shows the rear of the 760 opened up to expose the system board (the whole ball of wax is right there). In the foreground (left front) is the fully socketed 32K of memory that comes with the system. To the left, plugged Photo 8. Ago Kiss, Noval VP and general mgr. Photo 9. Noval's research and development lab.
TRS-80 Forum? It's very impor- gone wrong. tant that you let me know. Let's All "factory type" inquiries re- try the following format and see garding the TRS-80 should be ad- what happens. dressed directly to Hugh Mathi- as, customer service manager. TRS-80 You can call him directly at (817) Hashes from Fort Worth 390-3583. Hugh and his crew do yeoman service, and I think the enlightened attitude that RS is FORUM You aren't alone out there! taking towards customer service Dave Lien TRS-80 sales are very strong. It's is going to go a long way towards quite a surprise that about a third making the TRS-80 the world's trator. Hobbies include comput- of the Level 1 units arc being all-time best-selling computer. How lo Be)>in ers (obviously), writing (maybe ordered with I6K of RAM. That Somelhing like This? not so obviously), ham radio, fly- was a real sleeper. Read it and weep! Field failure ing, sailing; and I keep busy con- Best User Program rate is running a very low two per- By way of introduction, I'm sulting. I have no special ax to of the Quarter the culprit who wrote the operat- grind with or for Radio Shack. cent—not counting, of all things, ing manual for the TRS-80. Hav- The important person in this power-supply failures. Thought ing been part of the project from Forum is you. I'd really rather be that kind of problem was solved There is a classic computer its earliest days, 1 have some off running a computer, but John around 1932. Seems some well- printout from the "heavy small acquaintance with the sys- Craig has a mean hammerlock. meaning soul substituted fast- frames" that goes back many tem. Perhaps in a future Forum blow for slow-blow fuses in one years: Snoopy shaking his fist at we can wax nostalgic and talk batch of the scaled units. Any- the Red Baron. A microcomputer about entertaining and humorous way, the problem's supposed to version of that program simply And Away We Go . . . events that are part of the proj- be solved now-, and units being has to be added to each of our ect's history. delivered have the right fuse. software libraries. Much worse things could have 1 work as a college adminis- What do you want to see in the Tom Kasper of San Diego, one of the first TRS-80 owners, gets software honors this time 30000 END around for his version of Snoopy 30370 REM 'SIN* INPUT X IN DEGREES. OUTPUT Y. in RS shorthand with full TRS-SO 30380 IF X>360 T. X = X/360 : X = (X-INT(X))*360 graphics. Though we won't com- 30390 IF X>90T.X = X/90:X = INT(X*1000+ .5)/I000:Y = INT(X):G.30394 ment on his programming style 30392 G.30400 (and we're not going to be too 30394 X = (X-Y)*90:ONYG.30410,30420,30430 fussy about that sort of thing with 30400 X = X/57.29578 : G.30440 any contributors unless some ma- 30405 G. 30440 jor improvements are manda- 30410 X = 90-X : G.30400 tory), we think his final product 30420 X = -X:G.30400 on the screen is just superb! Beau- 30430 X = X-90 : G.30400 tiful job, Tom! 30440 Y = X-X*X*X/6 + X'X'X*X'X/120-X'X*X*X'X'X'X/5040 Why not submit your own fa- 30450 Y = Y + X'X*X*X'X*X'X'X'X/362880 : RET. vorite original program (on any subject)? (Don't worry about not Fig. I. Dave Waterman's solution. being a professional pro- grammer.) Your fellow TRS-80 owners are hungry for good pro- owners: little software or hard- grams, and will probably "mas- ware tricks you've discovered, sage" it a bit to suit their own questions of common interest, fancy, anyway. Never did see two complaints or just plain com- programmers who completely ments. The sooner you respond, agreed on how best to write a the sooner we can share your < 11 ( 11 OKSC YOI RD MM !M! program. feedback with others. Please We'll be able to publish short write (don't phone): 8662 Dent routines in the Forum, but, gen- Drive, San Diego CA 92119. erally speaking, lengthy pro- Dave Waterman of Alpine CA grams (such as Tom Kasper's) has contributed this valuable should be submitted as articles. feedback. It is a modification to Be sure to send your contribution the SINE subroutine found on (to Peterborough) on cassette page 218 of the TRS-80 User's tape; a hard copy would also be Manual. To confirm that a prob- helpful. Record it several times lem really exists, enter the sub- on the tape and include a tape routine as printed plus the follow- TmnsrcR SJIITS mailer and two first-class stamps ing lines: if you want the cas.sette back. 10 N = 179.95 20 X = N 30 GOSUB 30380 the other readers of the Forum ters is the typo in the Combined Compuler-Scannint> Ihe Future 40 PRINT N, know how it works for you? Function and ROM Test on page 50 N = N -I- .001 Meanwhile, we'll see how Dave's 227. Line 330 should read: 60 GOTO 20 Level II BASIC is not far away. new subroutine works in a really and RUN 330.F.X = OTOA : A(X) = Q : N.X It is nearly finalized at this writ- super Level I biorhythm program ing and looks very good. While The crash of the subroutine is he is working on, which should It seems that thousands of incorporating the most valuable due to the extremely tiny numbers appear soon. users thought they had bad ma- of the standard Microsoft fea- encountered as the value of the All things considered, the first chines because the factory test tures, it also retains most of the SI NE of 180 ° (and multiples of it) printing of the user's manual program said so. Well—it shows Level I features. is approached. Dave's solution is came out pretty well, but even that users really are reading the The cassette Data How rate has shown in Fig. 1 and seems to small typos cause great distress in manual. been nearly doubled, and the solve the problem without intro- a computer program. By far the More on these and other things built-in editor is excellent—simi- ducing any new ones. Why not let greatest initiator of cards and let- in a later Forum. lar to the SOS editor used on big DEC machines. Several printers are available but require use of the extra card box for interfacing. 3 REM SNOOPY BY T.N. KASPER, 5 JANUARY 1978.
Level 111 (for use with floppy 5 CLS disks) is close behind, and is a simple upgrade from Level IL 10 F.A=14T022IS.(A,0)1N.A Matter of fact, most of what's 20 F.B=12T015iS.(B,1)iN.B needed for Level III is already in- cluded in the Level 11 interpreter. 30 F.C=21T02<.lS. (C, 1 ) sN.C More on the future as we get 40 F.C = '.0T0'.5iS. (D, 1 ) iN.D closer to it. Tom Kasper's Snoopy listing, 50 F.E=10T012iS. (E.2) .N.E (continued on page 20) 60 F.F=21T025IS. (F,2 ) IN.F Feedback from Ihe Field 70 F.6=36T0391S.(G,2)1N.6
That's you! Since this is the 80 F.H=45T047>S.(H,2)iN.H first Forum, there is only one 90 F.I=9T010iS.(I.3)iN.I item of major interest from "the field." Only you can solve that 100 S.(12.3) little dilemma. 110 F.J=23T035iS.(J,3)sN.J Of special value will be items of broad interest to other TRS-80 120 F . K = Something for Nothing! Intertec's new INTERTUBEvideo ter- Our combination of price and performance There are lots of video terminals on the mar- minal is really sonnething! But most amazing gives a true advantage to a broad cross-sec- ket today but only the INTERTUBE de- is that it costs you almost nothing! The tion of users in the computer industry. livers significantly better performance for INTERTUBE's S784* price tag combined Whether your requirement is the most so- such an incredibly low price. So before you with our innovative microprocessor design phisticated data entry application or a sim- buy one of those dumb terminals or one of sets new standards in the CRT industry. ple inquiry/response environment, the those other smarter ones, you owe it to INTERTUBE is the best value for your ter- yourself to sit down in front of an The new INTERTUBE obsoletes dumb ter- minal dollar. INTERTUBE. While we admit our motives minals and out performs the smart ones. for recommending that you try the The INTERTUBE offers a variety of inter- Every INTERTUBE boasts such features as INTERTUBE are purely selfish, it's the only faces including RS-232C and 20MA cur- a full 24 line by 80 character display, 128 true way to appreciate the design features rent loop. Better yet, the INTERTUBE upper and lower case ASCII characters, re- and price advantage of our new terminal. interfaces beautifully with the user. Pains- verse video, complete cursor addressing and Mere words just can't do justice to the taking human engineering assures you of control, a 14 key numeric key pad, 16 pro- INTERTUBE. Contact your local dealer to- many hours of enjoyable operation without grammable function keys, blinking, a self- day and discover just how smart you'll be operator fatigue. INTERTUBE's high res- test mode, protected fields and much, much when you spend only S784 for your new olution CRT monitor provides the sharpest more. INTERTUBE. possible display image. And our special Accu-Dot"*"" focusing technique produces For the name and address of your nearest The new INTERTUBE video terminal from ultra clear characters on a non-glare screen. Intertec represents the latest advances in dealer, contact us at one of the numbers microprocessor technology. Speed, silence Our INTERTUBE not only offers unparal- below. It's the only smart thing to do. and flexibility, coupled with the many oper- leled price and performance but is also ator-oriented features of the INTERTUBE backed by Intertec's nationwide factory •S784 is INTERTUBE's "Quantity One- serve to boost the efficiency of both soft- trained service network providing over 250 Immediate Delivery" price. Dealer in- ware and programmers. local dealer and service center outlets. quiries are invited. INTERTEC DATA SYSTEMS Corporate Headquarters Eastern Regional Marketing Western Regional Marketing 1851 Inlerslale 85 Soulti 1 9530 Clut5 House noad 17952 Sky Park Blvd Charlotte. North Carolina Z8208 Gaithersburg Maryland 20760 Irvine Calitornia 927 14 704/377 0300 301/948 2-100 714,957 0300 INTERTEC's TUBE TERMINAL SPECIFiCATIONS MEMORY SIZE: 24 lines by 80 characters per line. ALPHANUMERIC CHARACTER SET: Generates all 128 upper and lower case ASCII characters. LINE DRAWING CHARACTER SET: Eleven special graphics symbols. DISPLAY PRESENTATION: Dark characters on a light background. (Display is reversable through keyboard selection.) VISUAL ATTRIBUTES: Blinking (2 frames per second), underline, reverse video, half intensity. SPECIAL ATTRIBUTES: Protected, constant and print-only fields. STATUS INDICATOR LINE: 25th display line reserved for terminal status messages. (Status line displayed as inverse of normal display.) SCREEN SIZE: 12 inch diagonal. REFRESH RATE: 60 frames per second (50 frames per second—Export model). OPERATING MODE: Conversational: character at a time transmission. Message: line at a time transmission. Page: full or partial screen at a time transmission. TRANSMISSION MODE: Half or full duplex, keyboard and switch selectable. KEYBOARD: Standard teletypewriter-compatible layout plus 14 key numeric pad, local mode and erase. Keyboard lock/unlock under program control. Also, 16 programmable function keys. SELF-TEST MODE: Self-diagnostic firmware testing routine-results displayed on status line. ADDRESSABLE CURSOR: Direct positioning by either discrete or absolute addressing. CURSOR CONTROL: Up, down, forward, backward and home—keyboard selectable. READ TERMINAL STATUS: Allows CPU to interrogate for terminal status, present cursor address and memory value at cursor position. PARITY: Choice of even, odd, marking or spacing-keyboard and switch selectable. WEIGHT: Approximately 37 pounds. PHYSICAL DIMENSIONS: 14 5/8" (H)x21 3/8" {W)x23 1/8" (D). ENVIRONMENT: Operating temperature between 0° to 50° C, Storage 0° to 85° C, 10 to 95% relative humidity, non-condensing. COMMUNICATIONS INTERFACE: EIA RS-232C/CCITT V.24 operates through the range of 75 to 19.2K BPS, switch and keyboard selectable. Available 20/60 MA current loop operates through the range of 75 to 9600 BPS. AUXILIARY INTERFACE: RS-232C/20MA current loop printer port. The most remarkable specification of the INTER- You don't have to buy a hundred terminals or sign a TUBE is its astonishingly low price. The feature- contract to qualify for INTERTUBE's low S784 price packed INTERTUBE compares with terminals costing tag . . . it's our "quantity one-immediate delivery" more than three times as much! Combine this price price. Additional discounts are available under OEM, with the inherent reliability of our microprocessor de- $784 GSA/Educational and Distributor pricing schedules. sign and the result is an industry first! * QUANTITY ONE! Contact an Intertec Marketing office for details. The INTERTUBE and other Intertec products are distributed in these cities: Albany, Alberquerque, Atlanta, Baltimore, Boston, Buffalo,Charlotte, Chicago, Cincinnati, Cleveland, Columbia, Columbus, Dallas, Dayton, Denver, Detroit, Hartford, Huntsville, Houston, Indianapolis, Jacksonville, Kansas City, Los Angeles, Louisville, Madison, Memphis, Miami, Milwaukee, Minneapolis, Nashville,New Haven, New Orleans, New York, Oklahoma City, Omaha, Philadelphia, Phoenix, Pittsburgh, Portland, Providence, Raleigh, Richmond, Rochester, Sacramento, Salt Lake City, San Antonio, San Diego, San Francisco, Seattle, St. Louis, Syracuse, Tampa, Tulsa, Virginia Beach, Washington, DC. International offices located in Australia, Austria, Canada, Denmark, England, France, Germany, Holland, Switzerland. to research and use (e.g., records the right to control information of your birth, marriage, criminal about ourselves come. convictions, ownership of real From the point of view of the property, address, etc.). Count- individual, the right to personal less other records (educational privacy in terms of control of in- transcripts, military records, formation about ourselves is a employment personnel files, relatively recent phenomenon. etc.), though not "public," are Man has kept records of births, accessible by numerous other marriages, deaths, etc., almost people. since he learned to write. They Even if you shudder at the were kept on a very local basis be- thought of a firm such as the fic- cause no methods were available tional International Data Base, for communicating their content. Kennelh S. Widelitz Inc., consider that every piece of Virtually no other information about an individual was record- Atlorney-al-Law information in their hypothetical dossier on you is already known ed. It wasn't necessary to ask a puter to invade what we com- to many other persons (the por- credit-reporting agency if a per- Personal Privacy monly consider our domain of nography company, the Commu- son was credit-worthy. Everyone personal privacy. nist Anti-defamation League, the in his village knew that he was or A discussion of personal pri- You are being interviewed for a airline-reservation clerk, the wasn't. vacy and computers looks at only job. After the usual meetings hotel desk clerk). You did not Perhaps it was with the inven- that portion of personal privacy with key executives, and the think in terms of invasion of per- tion of the Gutenberg printing relating to records and record- three-martini lunch, a clerk in the sonal privacy when you placed press, which made the wide- keeping practices. This comprises personnel department makes a the porn order, gave the contribu- spread dissemination of informa- a very small portion of what is or- critical phone call to Interna- tion, made the airline reservation tion possible, that the question of dinarily referred to as personal tional Data Base, Inc., which re- or checked into the hotel. the existence of a right to person- privacy. ports that although you have not You can see that in defining the al privacy was first raised. The Constitution does not had any prior criminal convic- concept of personal privacy with Subsequent technological ad- mention a right to privacy. tions or arrests, you have ordered relation to records and record vances resulted in the rapid com- Nevertheless, various aspects of $500 worth of merchandise in the keeping, it is not so much a con- munication of information over personal privacy have been pro- last year from a firm specializing cern that others know informa- long distances. Telegraph, tele- tected against government action in pornographic films. tion about you, but rather to phone and radio made the world by traditional interpretation of The report shows that you what extent that information is smaller and information on per- the Bill of Rights. The First bought an additional $200 worth compiled and communicated to sons outside our communities Amendment guarantees the rights of materials from an adult book- persons other than those who more important. That technology of free speech, freedom of assem- store, and made a $1000 contri- garnered the data on a first-hand gave us the means to invade the bly and freedom of religion; the bution to the Communist Anti- basis—that is, those persons nec- personal privacy of a limited Third Amendment prohibits defamation League. It reveals essary to consummate a transac- number of individuals, who tend- quartering soldiers in your home; that you travel without your wife tion. In this context, the right to ed to be the "important" people, the Fourth Amendment prohibits on business trips, but always privacy involves the right of an public people, such as politicians, unreasonable searches and sei- register at hotels as Mr. and Mrs. individual to decide for himself actors and actresses and com- zures; and the Fifth Amendment It also notes that during your when and on what terms his acts munity leaders. Although it was protects against self-incrim- sophomore year in college you should be revealed to the general possible prior to the computer ination. failed a computer-programming public. age to accumulate information Courts have interpreted these course. During the last five years, As stated by Charles Fried in on individual nonpublic persons, protections to prevent an individ- the report discloses, you have an article entitled "Privacy" the amount of effort involved in ual from being forced to reveal paid $10,000 to a psychiatrist. (Yale Law Journal, 1968, p. 482), terms of compiling such informa- political, social or philosophical You are surprised when you do "It is not true, for instance, that tion was relatively large. beliefs. Furthermore, the Su- not get the job. the less that is known about us the With the advent of the com- preme Court has indicated that To my knowledge, such dos- more privacy we have. Privacy is puter, the task of compiling enor- individuals have a right to privacy siers are not currently available to not simply an absence of infor- mous amounts of information on relating to their freedom to prac- potential employers. However, mation about us in the minds of an enormous number of people tice contraception, have an abor- virtually all the information from others; rather it is the control we became possible and economical- tion or read pornography at which such a dossier could be pre- have over information about ly feasible. Once the capability home. The judicial system has pared is presently in a computer ourselves." existed, the applications followed also developed principles that data base somewhere. Of course, for any individual, closely behind. It is with the ap- allow suits for invasion of privacy International Data Base, Inc., privacy as a value is not absolute. plications, such as credit report- in certain situations involving does not yet exist, but many Its importance can vary with sub- ing, that the issue of the right to financial or reputational injury credit-reporting agencies do. Fi- ject matter, time, age, etc. It must personal privacy and its invasion of one person by another. nancial institutions rely on such also be recognized that the right comes to light. The foregoing aspects of pri- agencies to provide information. of personal privacy can conflict Historically, the social utility vacy have nothing to do with the It is commonplace to read of per- with the interests of society (i.e., of record-keeping practices has notion of invasion of personal sons who have been denied fredit records maintained for criminal seldom been questioned. Certain- privacy by computer. "Invasion because of inaccurate reports investigations or national-securi- ly census information and other of personal privacy by comput- issued by credit bureaus. The ty problems). A conflict also ex- statistical records, along with er," of course, does not mean the cause of such inaccurate reports ists in the area of free speech and some intelligence (i.e., police, computer is responsible for inva- is uniformly attributed to "com- the public's "right to know." CIA) and administrative records, sion of an individual's personal puter error." are valuable and useful tools that privacy. It would be more accu- Back to our definition of per- have a positive effect on society. The Problem Historically rate to say "invasion of personal sonal privacy. From the above, it privacy by use of a computer." can be seen that the invasion of It is difficult to define personal personal privacy by use of a com- Having ruminated about the Privacy and Personal Computers privacy in terms of potential inva- puter relates to the compilation definition of personal privacy sions by use of a computer. Be- and dissemination of informa- and the right to it, vis-a-vis com- The foregoing discussion has fore we go on, let's speculate on tion. Some information about puters, it might be useful to con- some repugnant uses of a com- you is public, available to anyone sider from where our notions of (continued on page 21) Commodore PET computers and Toronto, Canada an extensive technical library. According to a brochure from Congratulations to the Toron- the public library, through "the KB €LUB to Region Association of Com- generosity of the membership of puter Enthusiasts (TRACE), the Columbus Amateur Comput- which celebrated its second birth- er Society, the Public Library of day in February. Columbus is now able to offer re- CALENDAR According to public-relations source materials to the growing secretary Ross Cooling, "TRACE number of computer hobbyists in Steve Fuller began in February 1976 as an in- the Franklin County area. Mate- formal meeting of ten people in- rials ... are available for loan at Richardson/Dallas/Fl. Worth TX Ojai CA terested in personal computing, the Business and Technology and quickly attracted followers. Division of Main Library, 96 S. Since that time the club has Grant Ave." W. P. Dart of 231 Valle Rio Here are the highlights of a let- grown to approximately 100 You can contact the Society Ave., Ojai CA 93023, wants to ter I received recently from Neil members and about as many ca- c/o Fred Hatfield, Computer hear from hobbyists in his area Ferguson, president of The Com- sual followers. Nearly half of the Data Systems, 1372 Grandview who are interested in starting a puter Hobbyists Group of North members have personal systems Ave., Columbus OH 43212, or computer club. His phone Texas: of some form. call (614) 488-3347. One of the oldest computer number is (805) 646-5824. "The main purpose of TRACE hobbyist clubs in the country, is to foster communication and CHG-NT holds two meetings per resource sharing among com- month—one for the Richardson/ Granger IN puter hobbyists and profes- North Dallas area and another Augusta GA sionals. The meeting format in- for members in Dallas/Fort cludes one or two talks on micro- Worth. Meetings are conducted A software/hardware library computer-related topics, and on the first and third Saturdays of The CSRA Computer Club to support the Apple-I computer usually a system demonstration. the month at 1 PM unless the dates meets on the third Thursday of has been started here. Interested The club also has a monthly conflict with holidays. Dues of $7 each month at 7 PM in the main persons may write to Joe Torzew- newsletter, group purchasing and per year include a subscription to auditorium of the Augusta-Rich- ski, 51625 Chestnut Rd., Granger a library of product literature, the club newsletter, "The Printed mond County Public Library in IN 46530. books and periodicals. Other ac- Circuit." Augusta. Rolston Wilder, 2704 Rose- tivities include fiea markets, ex- The June meeting will be the hibitions and a software library." club's annual swap meet, known wood Court, Augusta GA 30909, Midland/Odessa TX The club meets at the north as the "Chip and Dip Fest" in will send you a copy of the club campus of Humber College at 8 honor of the IC. Sounds great! newsletter. For more informa- PM on the fourth Friday of the The Permian Basin Computer For more information on the tion, write to Rolston or call (404) month and at the Ontario Science Group has scheduled meetings of club and its activities, write R. 733-8750. Centre on the second Sunday of its two chapters as follows: Neil Ferguson, PO Box 1344, the month. Newcomers are wel- Grand Prairie TX 75051, or call The Midland meetings will be come, and information may be him at (817) 265-9054. held on the second Monday of Rochester NY obtained from Ross at 488-3314, each month at 7:30 PM in the Stu- or Gifford Toole at 828-9202. dent Center on the Midland Col- lege campus. Meeting dates are: Atlanta GA KIM-1 owners in the Rochester May 8, June 12, July 10, August area are invited to join Murray 14, September II, October 9, Smith in forming a club. He says Hou.slon TX November 13 and December II. George Reeves asks us to an- he suspects there are at least 20 of The Odessa chapter will meet nounce that the Atlanta Chapter you out there, so get in touch with on the second Saturday of each of the SOL Users Society him at 1972 E. Main St., Roches- Information concerning activi- month at 1 PM in Room 203 of the (SOLUS) meets twice monthly, ter NY 14609. ties of the Houston Amateur on the first Monday and third Microcomputer Club (HAuCC) Electronics Technology Building Thursday. Consider it done, is available from Clifford Carley, on the Odessa College campus. George. corresponding secretary, PO Box Dates are: May 13, June 10, July 8, August 12, September 9, Oc- Incidentally, time and space 37102, Houston TX 77036; you Investors Club tober 14, November II and don't permit publication of club may call him at 921-7532. December 9. rosters, but thanks for the copy. The club's newsletter, "Nyb- ble," contains schedules of up- Details are available from the I'll know who to call next time The Microcomputer Investors coming events, product briefs Permian Basin Computer Group, I'm in Atlanta! Association, a nonprofit profes- and computer-related job open- c/o John Rabenaldt, Ector Send your requests for details sional group, has been formed to ings in the Houston area. County School District, Box of the current month's club ac- facilitate the exchange of infor- 3912, Odessa TX 79760. The tivities to George at 5002 Crowe mation relating to microcomput- phone number in Midland is (915) Dr., Smyrna GA 30080, or call ers and investments including 697-4607 after 6 PM; in Odessa, him at (404) 436-0718. stocks, bonds, stock options and Columbus OH (915) 332-9151 Ext. 43 from 8 AM commodities. to 5 PM. In order to benefit from the ex- periences of others there is a basic The Amateur Computer Soci- Pensacola PL requirement that, at least once ety of Columbus (ACSC) meets each year, each member submit at 7:30 PM on the first Wednesday Cornwall, England The second Thursday of each an original article for publication of each month at the Center of month is the meeting date for the in the association's newsletter. Science and Industry. North Florida Computer Society, If you'd like an application, President Fred Hatfield notes British hobbyists may obtain according to Eugene Rhodes. send an SASH to Jack Williams, that ACSC is working with the information about the Personal Write to him at 227 Edison Dr., The Microcomputer Investors Columbus Public Library to set Computing Club (PCC) from Pensacola FL 32505, or call (904) Association, 2415 Ansdel Court, up a "Computer Corner" where 453-3844. Reston VA 22091. patrons will have access to two (continued on page 21) _ NEW PRODUCTS ital Research CP/M. Among the Two New Mainframes from TEI software packages that operate under CP/M are two full versions TEl, Inc., has two versions of of Disk BASIC, including Micro- their Computer Mainframe Sys- soft Extended Disk BASIC tem available. The first is Model (4.41), $350. Also available is a The Centronics SI. MCS-112, a foundation unit Structured Systems Group based on an S-100 bus system QSORT ($95), a high-speed, gen- with a 12-slot motherboard. The eral-purpose sort package. A cost 2708 EPROM programmer. suited for use in diagnostic sys- power supply is rated at 17 Amps name and address maintenance Designated the POP-1, the unit tems, CRT hard-copy applica- at 8 V and 2 Amps at ± 16 V. system, NAD ($79), includes lists for $149 and is designed to tions, industrial instrumentation, The second version is Model mailing labels. The manufacturer interface to the company's P-38-1 and demand message printing. MCS-122, a foundation unit also states that all software is current- and P-38-FF EPROM boards, However, since many CRT ter- featuring the S-100 bus system ly available for immediate de- which are SS-50-bus-compatible minals require the RS-232 inter- with a 22-slot motherboard and a livery for use on INFO 2000 Disk products. Complete software is face, the SI should see frequent higher rated power supply. Both Systems. provided on audio cassette. A use as a remotely placed message models are housed in a heavy- Still available for Z-80 systems unique adaptive programming printer. duty, vented aluminum cabinet. is the complete TDL software technique allows most 2708s to be Information about numerous The power supplies consist of a package—including 12K BASIC, programmed in 15 seconds in- other features of the SI (and PI) constant voltage transformer macro assembler, Z-TEL Text stead of the usual 1 '/z minutes. A can be obtained from Centronics providing brownout protection Editor and Word Processor—ex- separate, self-contained power Data Computer Corp., Hudson and showing high noise immunity panded to operate under CP/M supply is used for the program- NH 03051. of better than 100 db between in- and Zapple operating systems. ming voltage to insure sufficient Price, $215. put and output. The front panels current capability to program of both fully tested and assem- All INFO 2000 software oper- EPROMs from any manufacturer. CP/M on North Star Disk bled models include an indicating ates on INFO 2000 Disk Systems ac switch and reset switch. Prices that employ the PerSci 277 dual are $395 for the MCS-112; $495 diskette drive with intelligent CP/M has become the most Microprinter with for the MCS-122. controller. The Disk System is widely used S-100 floppy-disk Serial Interface For more information, contact available for all S-100 microcom- operating system, effectively CMC Marketing Corp., 5601 puters using Z-80 or 8080 proces- making it the software-exchange Bintliff, Suite 515, Houston TX sors, for Digital Group Z-80 and Centronics Data Computer bus for S-100 systems. Vendors 77036. 8080 systems, and for the Heath- Corp. introduces the Microprint- of hardware or software support- kit H8. er-Sl with serial interface. The ing CP/M include Imsai, Cro- INFO 2000 Corp., 20630 S. new printer, which has a single memco, TDL, Digital Systems, Leapwood Ave., Carson CA unit price of $695, allows the user Tarbell Electronics, Microsoft, INFO 2000 Systems Software 90746. to select baud rates, parity and Digital Research and many Supported for 8080 and Z-80 the number of stop bits. others. Also, the CP/M Users' Centronics expects the SI ver- Group is currently operating a INFO 2000 disk-systems own- sion of the Microprinter to enjoy successful software exchange New EPROM Programmer ers may now utilize expanded an even broader range of applica- program. software for both 8080 and Z-80 tions than the PI, which debuted Now North Star Disk users can microcomputers. INFO 2000 Smoke Signal Broadcasting, last June. Both units are aimed at also join the software bus. With- Corp. has increased disk-operat- PO Box 2017, Hollywood CA the home, hobby and micropro- out any hardware changes, CP/M ing software capability using Dig- 90028, announces a new, low- cessor markets, and both are can be run with all the features available to the users of the system on standard Hoppy disks. Microsoft FORTRAN-80 and Disk Extended BASIC can also be supplied on a 5 '/S inch diskette to run on "CP/M on North Star Disk." All the software is fully 8080/Z-80 compatible. Retail prices: CP/M on North Star Disk, $112; FORTRAN-80, $400; Disk Extended BASIC, $300. FORTRAN-80 includes re- locating assembler and linking loader. Full ANSI except for complex data types. Disk Extend- ed BASIC is a CP/M generation of Altair Disk BASIC 4.1. All prices are freight inclusive. Lifeboat Associates, 36 W. TEI MCS-112. The POP-I. 84th Street, New York NY 10024. fast board include auto-jump GRAPHICS start-up and vectored interrupts. Available as a kit for $ 199 or $259 fully assembled. EPROM option costs are $49 for kit and $69 assembled. North Star Computers, Inc., 2547 9th Street, Berkeley CA 94710. SO RRE HISTOGRAMS Video Checkers on Cassette m 19M 1978 Compu-Quote, 6914 Berquist Typefaces may even be miXEC:- on the Ave., Canoga Park CA 91307, has developed several games on same line. cassettes, recorded in the Tarbell format and programmed in Mits The Axiom 801 and sample printout from the 820 ($795). BASIC (3.1). Contained on one cassette. Video Checkers pro- duces checkerboard graphics on publication. There will be 12 is- gramming language can use it. The Axiom Primer the CRT when used with the sues a year, each issue consisting The Computer Mart, 633 West PolyMorphic Video Interface of an audio cassette with six to Katella Ave., Orange CA 92667. and 64-character option. Two ten programs (more, if possible), Axiom has a printer, the EX- versions of the program on one an index and an instruction sheet. 801, part of the EX-800 series, for 60-minute cassette play a chal- Subscription rates available. fast and inexpensive printing. It lenging game that conforms to 4 MHz Z-80A Processor Board prints on aluminized paper ($4 CLOAD Magazine, Box 1267, International Rules. The first ver- per 230-foot roll) by passing a Goleta CA 93017. sion requires a total of 16K of current through the aluminum The ZPB 4 MHz Z-80A proces- memory, inclusive of 8K BASIC. coating, evaporating it and thus sor board is one of several new The second version is more leaving the black-coated paper high-performance products graphic and requires an addi- underneath exposed. Moisture New Business Software Program North Star offers for S-100 bus tional 4K. and sunlight have no effect on the computers. The ZPB will operate As the player and computer paper. The current is passed A new, low-cost ($200) gener- in systems with or without front each take turns, the checkers through eight wires, making a al-business software package for panels. It includes space for 1K of blink and move to indicate their dot-matrix pattern without the microcomputers that includes 2708 EPROM. need for moving wires and their general ledger, accounts receiv- Other features of this versatile. (continued on page 114) fragility. able, accounts payable, finished- The printer, with an 8048 goods inventory control and pay- microprocessor in control, has an roll has been introduced by The input buffer of 256 characters Computer Mart, Orange CA. which can be expanded to 2K, Developed by Larry G. Grimes thus providing a full CRT page & Associates and Computer dump at one time. It will work Products of America, a subsidi- from RS-232, 20 mA serial as well ary of The Computer Mart, the as parallel ASCII. It comes with 24K Grimes Business Informa- 96-character ASCII standard and tion System (GBIS) is specifically is expandable to 256 characters designed for small businesses. In with your own programmable a typical application, the GBIS fonts. Three character widths, can store on a single minifloppy which can be software-selected to diskette up to 400 customer list- provide 20, 40 or 80 columns on ings, 50 vendors, 400 line items of the 5-inch-wide paper, can be inventory, 25 employee records mixed on a line for emphasis. and 60 general-ledger accounts. Axiom Corp., 5932 San Fer- GBIS is written in North Star nando Rd., Glendale CA 91202. BASIC, although other disk BASIC languages can be used for the listings. Programs are written so that someone with a minimal Audio Cassette Magazine understanding of the BASIC pro- Video Checkers in action. CLOAD Magazine, published by R D McElroy & Co. of Goleta CA, and written especially for Radio Shack's TRS-80 computer, is something new. It is "printed" on a standard audio cassette and will load directly into the TRS-80 computer. Its "articles" are pro- grams ranging from short games to involved programs of a practi- cal nature; emphasis will be on education. People can submit programs for CLOAD Magazine. North Star's ZPB. sically reverted to the technically MUHAMD or adding the con- thorough but very dry style of his tents of two double-precision other books. In his defense: He is fields named INSULT and IN- dealing with more complex data JURY help make the learning M O ^ at this point. In truth, there fun. In a chapter on controlling a ^ 2 ft would be no objection to this if he complex peripheral (the Victor hadn't done such a damn fine job matrix printer), examples include in the first part of the book. routines to transform ASCII to In summary, Mr. Osborne has required bit patterns for printing delivered a first-rate book for the the Cyrillic alphabet. This new novice computer hobbyist. It is code (named by the authors) Rus- i^lBOOKS successfully aimed at that great sian Unified Standard Key for In- throng of people who would like formation Interchange (RUSKII) to use computers but care no is then printed. Understanding more about the design and repair this chapter will leave the hard- Chapter 4 is the obligatory dis- An Introduction of such devices than they do ware freaks with little fear of cussion of binary/octal/hex to Microcomputers about the internal workings of tackling an APL printer. arithmetic and logical opera- Volume 0, The Beginner's Book their refrigerators. This is a su- tions. There are numerous ex- At no point do the authors Adam Osborne perb book for any beginner and amples, and the explanations are resort to rehashing material avail- Adam Osborne and would serve very well as the text unusually lucid. able from the manufacturer of Associates, Inc. for an introductory class at any the 8080, but instead choose to Chapters 5 and 6 deal with soft- PO Box 2036 level from junior high school on take a less theoretical, more prac- ware and with system organiza- Berkeley CA 94702, 202 pages up. tical approach. Oh yes, there is tion. The software discussion de- even an index to allow use as a fines those mysterious terms—as- Art McDonough reference manual. One minor ob- Hallelujah! At long last, some- sembler, compiler, interpreter— El Segundo CA jection is that the examples do not one has actually produced a book clearly and concisely. With those strictly follow manufacturers that really is for the absolute concepts established, the chap- standards for assembly-language novice in computer technology. ters describe the various ap- programming—labels are not fol- Like many books before it, this proaches to machine organiza- Practical Microcomputer lowed by a colon and comment one claims to be written for peo- tion. The advantages of different Programming: The Intel 8080 lines begin with a "•" rather than ple who know nothing about word lengths, of different num- Weller, Shatzel, Nice a ";". The style is similar to computers. The novelty is that bers and arrangements of regis- Northern Technology Books assembly language used on larger Osborne et al mean it; and what is ters, and other computer ele- Box 62, Evanston IL machines. even better, the book is for the ments are clearly explained. The 60204 $21.95 Any 8080 or Z-80 user would potential user who doesn't know author's intent in these chapters do well to purchase this work, for how a computer works, will prob- is to bring the reader along to a learning and for reference. ably never know and doesn't par- point where he can intelligently Want to know how your 8080 ticularly care. It is written for a read the specifications of various microcomputer really works? Tim Turner pure user orientation, treating the devices and systems and evaluate Thinking of writing or modifying Spokane WA microcomputer as an appliance these in the light of his own par- system software? Tired of and recognizing that it is possible ticular requirements. BASIC? Ever wondered about to use the appliance without At least one other aspect of The the "Playboy" effect in decimal knowing how to design it, modify Beginner's Book deserves not arithmetic? A necessary step is to Take a Chance it or repair it. The reader need only mention, but unrestrained learn assembly language, and this with Your Calculator only know that the microcom- praise: It is readable, even enter- book is for you. puter exists, that it is potentially Probability Problems for taining. The eager, but frequently Throughout the 18 chapters capable of performing interesting Programmable Calculators misguided, Joe Bitburger is an and 306 pages, the reader is intro- functions and that he'd like to use Lennarl Ride, Dililhium Press engaging hero. He helps to keep duced to hardware features of the one. PO Box 92, the text oriented to a user (rather 8080, presented in a clear, con- Forest Grove OR 97116 Starting from those basic than a designer), and to a rank cise, logical manner. Over 80 ex- assumptions, the book takes the beginner at that. The generous amples are included, most of reader logically and painlessly use of graphics and cartoons aids which are usable as subroutines Take a Chance with Your Cal- through a survey of the current in understanding the text and to programs you will want to culator will help you understand state of microcomputers. The demonstrates (if it was required) write later. Complete chapters basic probability theory by run- first chapter does nothing more that visual aids and humor can in- are devoted to such topics as ning experiments on your pro- than identify the major boxes crease the impact of even tech- stack pointers, arrays and tables, grammable calculator. that make up a microcomputer nical writing. binary/decimal conversion, com- The book is divided into three system and explain some basic Less this sound like a commer- munications with terminals, in- sections. The first is composed of data recording concepts. Chapter cial for Osborne and Associates, I terrupts and subroutines. Sixteen eleven chapters containing a total 2 introduces the book's hero, the should mention that the book pages are devoted to debugging! of 143 problems to be investigat- indomitable Joe Bitburger. In re- does have a few fiaws. As an ex- A powerful plus for this book ed, along with some explanations counting Joe's experiences with ample, on pages 5-21, the text is the authors' determination to of the problems and the methods his first basic kit, Osborne de- refers to a drawing and says that demonstrate why and how to use to be used in solving them. The scribes the frustrations of operat- the number representing an in- each instruction, not merely to second section has 46 pages of ing with only front-panel switch- struction code is circled. In fact, explain how it works. Examples more detailed write-ups on many es and lights for input/output. there are no circles on the draw- are described first in a short para- of the problems. Section three This brings up consideration of ing and the referenced number is graph, then presented in program has over 100 programs, written the Teletype and of keyboard en- in a shaded block. This sort of format with instructions printed for Hewlett-Packard HP-25-type try in general. That consideration thing can be confusing, but there in bold letters for easy readabil- calculators, which are used in leads logically into Chapter 3, are few such errors. ity. No matrix-printer-with-a- solving the problems from sec- which introduces the concept of A second objection is that the weak-ribbon printing here! tion one. logical units (files and records), very readable style of the early Reader interest is maintained Section one contains the real as opposed to physical units, and chapters is not carried all the way through occasional use of humor; meat of the book. It starts with a discusses various components through the book. By the end of interchanging memory locations method of generating random and devices in considerable depth. Chapter 6, Mr. Osborne has ba- named MOUNTN and numbers and then gives methods of testing random-number gener- clude an explanation of the prob- lated the standard deviation, Computers, Computers, he has ators. These are followed by lem, mathematical formulae, dia- nowhere are you told what it rep- pulled together a wide assortment chapters dealing with the genera- grams, fiowcharts or hints on resents or what it can be used for! of fictional treatments of com- tion of specific types of random how to program a solution for the Even with its faults, there is puters. The result can be enjoyed numbers, such as the number of problem. In many cases, a refer- still a lot of useful material in equally by both computerniks spots showing when you throw a ence is given to another book Take a Chance with Your Calcu- and nontechniks. pair of dice. where a more detailed treatment lator. The beginner will certainly The book's 18 short pieces of Chapter 5 investigates assorted of the problem may be found. learn some new concepts; the fiction fall into three categories. problems dealing with random Section three has 79 pages of reader with more background The majority (11) are science-fic- numbers, and other problems in- calculator programs and instruc- may be given a more intuitive feel tion short stories by such authors volved in drawing marbles from tions relating to their operation. for the theory after observing it in as Robert Sheckley, Gordon an urn containing both black and The programs were written to practice. On the other hand, if Dickson, Robert Heinlein and white marbles. Chapters 6 and 7 work on HP-25-type calculators. you are trying to learn probability Barry Malzberg. (In my opinion, deal with towers made of blocks The book claims they will also from scratch, you will need a bet- Malzberg's contribution, "The and the results obtained when run on Texas Instruments SR-56 ter textbook than this. Union Forever," is his most suc- you move a random number of calculators; but 1 believe some cessful short piece.) blocks from one tower to another modification to the programs will Glen Charnock Another category is satire, and randomly selected tower. be needed since the programs ap- Oxnard OA here we find pieces by such lumi- Chapter 8 examines "runs" pear to be written for Reverse naries as Art Hoppe, Art Buch- that are sequences of the same Polish Notation machines. Texas wald and Bob and Ray. The third Instruments uses algebraic entry. category, poetry, includes 18 random digit repeated several Computers, Computers, computer-tinged limericks times in a row. Chapter 9 is about The overall organization of the Computers: In Fiction ("Glorobots" by Gloria Max- random walks, when you ran- book is rather poor. I constantly and in Verse son), as well as several more ex- domly walk either right or left a jumped from the problem state- D. Van Tassel, editor tended poems and a song ("Push random number of paces, and ment in section one to the com- Thomas Nelson Inc. ments in section two to the pro- the Magic Button"—to the tune other extensions to this type of 30 E. 42 St., NYC gram in section three, then back of "Puff the Magic Dragon"). walk. Chapter 10 defines statis- $6.95, 192 pages tics terms, including consistency to section one again. If all of the Although the stories, articles of an estimate, efficiency of an material for a given problem were and poems can be read and ap- estimate and confidence level, collected in one place the book Dennie Van Tassel, author of preciated separately, it seems and exhibits test problems. would be much easier to use. several successful books for com- more interesting to view the col- Finally, Chapter 11 comprises 1 think the greatest fault with puting professionals, has been lection as a whole. In so doing, more miscellaneous problems in- the book is that the author didn't gradually moving into broader try to extract from the different cluding family planning, the seem quite sure just how ad- areas. The Compleat Computer treatments some common notion birthday problem, simulation of vanced his reader would be. In (reviewed in Kilobaud No. I) was of what nontechnical people have an election and queuing problems. some cases explanations are given a tasty assemblage of semitechni- thought computers will do to us. Section two consists of com- in detail, while in others there is cal articles, news items, cartoons The title of the author's introduc- ments on the problems in section no explanation at all. For exam- and some fiction, organized tion says it—"Make Way for the one. Not all problems have com- ple, problem 23 asks you to com- around specific issues of interest Machines." ments, and some comments are pute the standard deviation. Sec- to those attempting to under- quite brief while others are tion two gives a formula for this stand the effects of computing on Rich Didday lengthy. The comments may in- calculation; but having calcu- our society. Now, in Computers, Santa Cruz CA seems to get really nasty in small- larly if there is no source available. business systems. I suppose one 3. Most video boards require a reason is that it all sounds so sim- good-sized driver program. This ple! The boards are proven, the driver must be present in memory software is extensive. Everything concurrently with your BASIC required sits right there in front interpreter, or whatever, and fur- of you. All you need to do is thermore, each program that make a few patches here and must access this drive (probably there and write a little applica- all) will have to have references to tions software. this driver in it. Of course, it's those little de- 4. All dynamic memory boards times small, but it's almost al- tails that get you every time. Since require a refresh cycle. Even From Don Tarbell ways at least ten times as big as I get many calls from people though some manufacturers will you think. This difference is about their problems, I'd like to claim theirs is done at a time that It seems that many new com- called system design and integra- present short answers to a few is "invisible" to the rest of the puter customers have been given tion, and there are companies that seem to recur. system, there is no guarantee that the impression that it's easy to get that make millions of dollars do- 1. Many Z-80 CPU boards some other manufacturer's board a computer system up and going. ing things like it. This phase is don't create a true Altair-bus en- won't need to access memory at The truth is that it can be a can of when you discover that all "S-I(X) vironment. This means that al- this same "invisible" time. worms, depending on the user, compatible" boards are really though the CPU board will work 5. Some programs that work the components and the system not compatible with each other. in some situations, with some fine in your main computer mem- required. It's when you find out that two memory and with some inter- ory (RAM) may not be easily There is one thing in particular big expensive pieces of software faces, it may not work with the modified to work with a mass- that many people don't seem to can't talk to each other. It makes combination you want. storage device such as a floppy understand: There is a world of people work weeks or months 2. Most 8080 software is writ- disk or cassette. Often a whole difference between a bunch of without getting anywhere. In ten to run at a particular location new approach is required. hardware and software computer short, you stand to lose your shirt in memory. If two programs that 6. Noise is almost always a components and a computer sys- if you don't know what you are must run together are written to problem. Some S-100 buses have tem up and working and doing doing! run in overlapping memory, one more noise than others. Termi- what you want it to do. This dif- Everyone runs into system in- must be moved. It is not always nating resistors don't always ference is sometimes big, some- tegration sooner or later, but it easy to move programs, particu- help. The third prong on one wall plug may not be connected to the people like this. They've had the third prong on another wall plug experience to know which boards (would you believe 50 volts of work with which, and which soft- difference?). ware is useful. If you want to 7. Be sure that there are no two shop around and buy one piece interfaces that use the same port here and one piece there, directly numbers. from the manufacturers, you're 8. There is no real standard on taking on the job of designing the U console port numbers, so either system yourself. So don't blame software or hardware may need the manufacturers or the stores to be modified. Sometimes the where you bought these separate hardware is easier. items for your problems. If 9. ASCII is not always ASCII, you're not willing to take the sys- RS-232 is not always RS-232, etc. tem's responsibility (and that in- 10. Some mainframes that cludes maintenance) on yourself, i--®- don't have a front panel also find someone who will. don't provide some of the re- Some manufacturers claim to quirements of the bus that a front be selling computer "systems." panel would have, such as pull-up Watch out! Is the manufacturer resistors, MWRITE line, etc. local? Does he provide a good 11. Because every single com- warranty on the complete sys- ponent in your system tests good tem? Will the software he pro- in someone else's system, that vides really do the job? My feel- doesn't mean they will all work ing is that only the largest manu- together. The best test is the facturers, such as IBM, DEC by the author. By leaving the two reasons: (1) to try to .stem the whole system the component will and UNIVAC, can afford to pro- TVT-II Cursor Control board in flood of biorhythm programs be- work in. vide local support for complete place, removing the 7445 and us- ing published and (2) to demon- 12. There is no memory test business systems of any size (even ing the bit signa]^available_at its strate the proper way to share that goes through all the com- the smallest). That's why I've socket plus the 4, 5 and 5 sig- algorithms (i.e., in an implemen- binations, regardless of what chosen to avoid the word "sys- nals available elsewhere on the tation-independent form). Take anyone might say. Figure it out tem" in any of my advertising board, a 32-character, strobed note that an algorithm is not a yourself if you must, but such a and refer as much business as decoder can be made using only program (all apples are fruit, not test would take longer than your possible to a customer's local two 74159s and half of a 7404. all fruits are apples). lifetime to run. After all, what is dealer. I would rather sell mostly The enclosed schematic shows the Though the exchange of pro- 2A(4096*8), anyway ... and to true computer hobbyists, arrangement I am presently using grams should be encouraged, the then, of course, there's the bit dealers and system designers. in my TVT-11. The page select, 6502 owner derives little from a that drops out after time . . . I hope that the above has cursor control and outside-world Z-80 chess program, much from 13. Programs always take at helped someone. I don't want to commands are implemented in the algorithm for collecting the least five times longer to write discourage anyone from getting a basically the same manner as set of squares containing pieces than you most conservatively es- computer system. I use one in my shown in Fig. 3 of Mr. Wright's that can be captured by either timate, even when the hardware own business and feel that it's one article using this simplified color. works perfectly all the time, of the most valuable assets I have. decoder. An algorithm can be pro- which, of course, it won't. I just want people to have enough grammed in any computer lan- 14. Requirements for software information to buy at the right Roger Wileman guage—BASIC, PASCAL, Z-80 should be specified before those place. Escondido CA or 6502 assembler. An algorithm for hardware. Design the system is more machine independent from the top down if possible. Don Tarbell than a BASIC program. The preceding is not meant to Tarbell Electronics I feel cheated by every pro- give everyone a crash course in gram that is published in assem- Algorithms and system design, but only to point Many thanks, Don. This is a bly-language for a machine I'm Flowcharts, Please out that there may be problems problem we've been trying to not familiar with—I must try to you haven't thought of. If you bring out in the open for some conjure the algorithm from the are a hobbyist, you are probably time. Now, if we can just get As a KIM-I owner and graphic code in order to make use of it, willing to learn (sometimes the some articles into Kilobaud deal- programmer by trade, I feel jus- and try not to get sick at a KIM-I hard way). If you're a systems de- ing with the problems encoun- tified in donning my cloak of program that can't be placed in signer, be sure to keep on learn- tered in system integration righteous indignation when con- ROM because it's self-modifying. ing. And if you're a businessman, . . . the benefits will be tremen- fronted with Larry Woods' bio- But to get back to my original find someone who really knows dous. —John. rhythm program (Kilobaud No. purpose for writing—I feel that what he's doing to help you out. 14, February 1978). the editors must take more re- It may cost you as much as you In any program, one must sponsibility in ferreting kludges paid for the hardware and soft- compromise between the two from this publication. You could ware (or more); but, believe me, mutually exclusive ideals—small start by requiring that a set of Response to if you don't have the time or in- size and quick execution. Al- flowcharts accompany every October Article clination to learn it yourself, the though a biorhythm algorithm is assembler program. money spent is well worth it! trivial, Larry's program is not. Starting with a published al- In the past several months, I've As a TVT-II owner, I read with The DAY # algorithm in the gorithm, rather than a machine- talked to many people who are in interest Richard Wright's article algorithms I have provided will dependent program, each reader trouble now because they under- (Kilobaud, October, 1977) de- work for any date between I can write a program for his own estimated the task they under- scribing ways of decoding the March 1900 and 28 February machine that takes advantage of took. These people would have much needed additional ASCII 2100. I found it in an old com- its unique environment (I/O rou- been better off if they had re- control codes. The circuit shown puter journal. As a side effect, tines, math software, addressing tained someone who already in Fig. 1 should not have been dis- MOD (DAY # (D, M, Y), 7) modes). made the mistakes a few years missed so quickly, though, as the yields the day of the week—SUN I don't want to see a Compu- ago. The computer stores around substitution of a 74159 open-col- :: = 0, MON :: = I, etc., so why Craft micro APL program for the the country, especially the older lector decoder for the 74154 over- all the tables? game of checkers with a Cyber- ones, are the best places to find comes the "one flaw" mentioned I share these algorithms for Clops CRT/TTY MK IV, but I might try my hand at program- computer user, one that was long those of us who are deciding on a (one-half the length of a note) by ming go-maku for my KIM-1 if I overdue. One wonders why some system but who haven't the coding in a SOI. The change is had an algorithm in a structured of the systems manufacturers knowledge or resources available simple and adds only 21 lo bytes to psuedo-language. don't pick up the ball and con- to make an intelligent decision. the code. It makes my version of tribute to the enhancement of I also found the article "Un- "Mary Had a Little Lamb" much D. A. Harrod their systems with such "innova- derstanding Loaders" very infor- more understandable. Rochester NY tions." mative and helpful in my coming 1 also set it up so the program Mr. Parsons' article, "Under- to a decision on a system. gets its speed parameter from a As a mailer of policy we always standing Loaders," was an ex- Please give the readers more ar- table (the speed value), instead of try lo insure lhal flowcharts are ceptionally well-written and time- ticles concerning product evalua- writing it into the code. This included wilh soflware arlicles. ly article. His portrayal of a sys- tion and performance vs price. makes it possible to burn the pro- Somelimes we slip up, loo. As tem's software as a series of load- Very few of us have other re- gram into a PROM and still be far as Larry IVoods' arlicle is ers, one bringing in the next in a sources (computer stores) for able to change the speed. concerned, it works. As a mailer hierarchical manner, is a very im- which to make these evaluations. I have tried both these changes, of fact, I ran it on the day I re- portant concept for users to Your critical advice will be great- and both are incorporated in the ceived your letter and il said I grasp. One can even say (stretch- ly appreciated by your readers. listing shown. As I write this let- was al an emotional peak. Your ing his analogy to its limits) that ter, another change, which 1 letter took care of that!—John. the software of a system is only DwiKht T. Still haven't tried yet, occurs to me. Lawrenceville GA As the program is written, it plays eight different versions of 'he song, then repeats the cycle, ac- BIORHYTHM: PROC; tually, it only p/o^s seven versions AGE = DAY # (TDAY, TMON, TYR)- since the eighth has all output bits DAY # (BDAY, BMON, BYR); disabled and, therefore, plays PHYS = MOD (AGE, 23) Micro Maestro Modification nothing. This silence is annoying EMOT = MOD (AGE, 28) in a long song. INTL = MOD (AGE, 33) END BIORHYTHM; I tried Terry Perdue's "Micro I suggest the following modifi- Maestro" program in the Jan- cation to cure this. After the INC DAY # (D, M, Y) uary 1978 issue. Given the sim- S8004 instruction, insert these IF M > Z plicity of the program and the two lines: THEN DO "interface," I was pleasantly sur- TST S8004 K = Y prised by the results. Terry must L = M -t- 1 BEQ REPLAY be complimented on his arrange- OD ment of "Somewhere My Love." I think this will eliminate the ELSE DO After playing with it for a w hile, I "silent song." K = Y- 1 became frustrated by the pro- L = M+ 13 Well, that's about all. If you OD gram's inability to play rests. I haven't tried the musical micro, I modified the program slightly to urge you to do so. It's neat! FI allows rests—a whole rest (the K = INT (365.25 * K) L = INT (30.6 • L) length of a note) by coding S02 in- Don Korte RETURN K + L-t-D-621049 to the table, and a "half" rest Flint MI END DAY # I M K" RUS ] 1 2 • made of loaders including ap- i • NieBa 'tU'.IC »• ifl Y 2 HP POOP-. n Innovations from the plications programs that load I . wstn IE H f-t Mil Hobbyist Community i 1 LOi*A'.iC> JHHUDCYi*7 e p •<* data, subroutines and user com- • 6 • "^Ovlf : f •• 6 TOO M KOfcIl mands. Mr. Parsons' fluid writ- • IIll us HALF . N^.U coot'9 1 I have been reading Kilobaud ing style enables him to present t B Il lows WNOL PEfl . NOU C0t>E»92 complex topics in down-to-earth 1 2 150 since it was first published, and I ee^e 09C1 9 1 3SP f f [> f t>Ei IB 160 F.M=53T057:S.(M,5):N.M to their nearest computer store and a book called Hobby Com- 170 S.(4,6)iS.(16,6)!S.(19,6)!S.(20,6)!S.(21.6)!S.(27,6) puters Are Here. All the funda- mentals are there, written for the 175 S.(28,6) beginner. It starts with a chapter 180 F.N=53TOS7:S.(N,6)!N.N on what a computer is, then goes on to how it counts, binary num- 190 S.(3.7)iF.P=16T020iS.(P.7):N.P bers and arithmetic. It explains 200 F.Q=52T056iS.(0,7):N.Q the basics of computer languages, and then goes into the circuits 210 S.(2,8)!S.(19,8):S.(50,8)!S.(51,8) that make up a computer: gates, nip-flops, etc. This is the ideal 220 S.(2,9)iS.(19,9):F.R=28T049:S.(R,9)sN.R first book. It costs $4.95 and, as 225 S.( 18, 13) sS.(25. 13) should be no real surprise, we publish it. 2 30 S.(l,10)iS.(18,10)iS.(27,10)iS.(l.ll)iS.(8,ll).S.(9,ll).S.(10,ll) 2A0 S.(18.11)iS.(26,ll)iS.(l,12):S.(7.12):S.(ll,12):S.(18,12) 250 S.(25,I2):S.(l,13)iS.(6,13)!S.(7,13):S.(12.13) 255 S.( 18.13 ) IS. (25.13) AROUND 260 S.(l.l 280 S.(2.15)iS.(8,15)iS.(12,lS)!S.(19.15) (from page 8) 290 S.(26.15) 310 S.(2.16)iS.(9.16):S.(10.16)iS.(11.16):S.(19.16) The Noval Team 330 S. ( 27 . 16 ) ! S. ( 3, 17 ) : S. ( 19, 17 ) 340 F.A=28TD37iS.(A.I7iN.A!S.(A6,17)iS.(47.17)!S.(48,17) Let me introduce you to a few of the key people who keep things sonal computers owned by indi- 350 F.A=51TQ5 in both hardware and software purchase all kinds of information 390 S.(5.19):S.(22,19)IS.(3S,19):S.(44,19)!S.(53,19) developments, and really put the about individuals in the same system through its paces while 1 manner they can buy mailing lists iiOO S.(6,20)iS.(7,20):S.(22,20):S.(33,20)!S.( to share with you, but my camera (from page 13) 550 S.(28,28)!F.A=40T0 43!S.(A,28)iN.A started acting up. When 1 at- tempted to use the strobe, the H. G. Humphrey, chairman, c/o 560 S.(28,29):S.(32,29):S.(43,29)!S.(44,29)iS.(45,29) charge for firing it off came out The Micro-B Computer Store, 22 580 S.(27,31)iS.(29,31)iS.(34,31)!S.(48,31):S.(49,31) of the camera into my left hand Lemon St., Truro, Cornwall TRl . . . passed through my body 2LS England. 590 S.(26,32)!S.(30,32)!S.(35,32):S.(50,32) . . . and then returned to the camera via my right hand. Felt so 6 00 S.(26,33):S.(31.33)IS.(3S,33):S.(36,33):S.(51,33) If your Club Calendar announce- good 1 just had to go back and try 610 S.(26.34):S.(31,34)!S.(36,34)!S.(37,34):S.(51,34) it again! ment contains timely, in addition to general, information about Terry Sorenson, Noval's Chief 620 S.(25,35)IS.(31,35):S.(38,35)!S.(50,35) your club, please mail announce- Engineer, was one of those 1 ment at least two months before 630 S.(25,36):S.(31,36)!S.(39,36):S.(49,36) missed during my camera misad- the date or dates mentioned in the ventures, but he was sure helpful 640 S.(25,37)!S.(29,37)!S.(37,37)IS.(38,37):S.(48,37) announcement. Please mail all during my visit, the invitation for Club Calendar-related material 650 S.(26,38)IF.A+30T0 33:S.(A.38)IN.A which came from Jerry Hansen, to: KB Club Calendar, c/o Steve the president of Noval. All I can 660 S.(38,38):S.(47,38) Fuller, PO Box 218, Spofford say about him is that he's NH 03462. 670 F.A = 27T029!S. (A,39 ) !N.A definitely one of the "white-hat good guys." As I said earlier, it's 680 F.A = 33T037!S. (A,39 ) sN.A a "people organization." They Attention, Authors! not only have a knack for making 690 F.A=44T046:S.(A,39)iN.A you feel at home during a visit 700 S.(30,40):S.(31,40):S.(33,40)iS.(41,40)15.(46.40) . . . I'll bet they make you feel If you write an article for Kilo- just as much at home when you baud, and if that article con- 710 S.(32,41)!S.(33,41)!S.(4I,41):S.(46,41) do business with them. tains program listings and/or 720 S.(33,42):S.(41,42) runs, please submit camera- ready listings/runs. Use a 730 F.A = 46T056!S. (A,42)-.N.A printer (borrow one if you 740 S.(33.43)iS.(41,43):S.(56,43):S,(57,43) don't own one), and please be certain that the machine used 750 5.(32,44) produces dark, clear copy 760 F.A = 41T051 :S. (A,44 ) !N.A (also, try to avoid misspell- ings). If you must use a type- 770 S. (56,44 ) :S. ( 57,44 ) writer, and If it doesn't have a 780 5.(31,45):S.(32,45) carbon ribbon, please make sure that it has a relatively 790 F.A=51T056IS.(A,45):N.A (from page 12) new ribbon. Single-space (or, 800 S.(31,46)!S.(32,46)!S.(51,46)JS.(52,46) preferably, use space and a related the right of personal pri- half if your machine has this 810 F.A = 32Ta51 iS. (A,47) :N.A vacy to large computers owned capability) particularly if the and used by various agencies of 900 P.A.271," •»•••• CURSE YOU RED BARON ::::" listing or run is a long one. government and large private or- This will make our job immea- 910 P.A.936," TOM KASPER 5 JAN 78" ganizations. Before, the issue had surably easier. Thank you. I never been raised in terms of per- 10000 G.10000 Ralph Wells my own, derived primarily from Vice President Engineering personal PETting and aug- Inmarco, Inc. mented by the published 7655 Sunset Blvd. references and conversations Hollywood CA 90046 with sales representatives. To start with, I'll dive into the deep end of the pool of con- troversy and say that, in my opinion, they're going to make it—and make it big! Not with the model I received (serial 171), but because of vertical integra- PET'S First Report Card tion and forward-thinking management. an objective evaluation Setting the Stage Let's review some history to get a perspective of the pros and cons of grading the PET #171. In a sense, this is more of a mid-term interim report card because the PET's true poten- tial has not yet been adequate- ly documented. I've spent most tempt to answer some of these of my time trying to find out (the questions on an unbiased ba- hard way) just what I bought. sis (I'm not selling anything). I There is a gnawing feeling in have personally built or bought the pit of my stomach that they and modified three 8080-based, are going to follow in Radio five 6800-based, three Shack's footsteps and not tell 6502-based and one SC/MP- me much more than I already based microcomputers, so the know. PET has a lot to live up to. From my point of view, the Background PET is really the third product In December 1977, Com- from MOS Technology, preced- modore had never advertised ed by Jolt and KIM (see Photo the PET, but the magazine ar- 1). Although the Jolt is pro- ticles, television exposure and duced by Microcomputer Asso- convention displays made it a ciates, its debut was a result of pre-production marketing phe- their synergistic relationship Photo 1. A family portrait: PET, center, with granddaddy, Jolt, left, nomenon. In fact, I assume the with the then almost-unheard- and proud father, KIM, right. reader has already been ex- of MOS Technology. It was the posed to its fundamental first microcomputer to really specifications. In case you take advantage of read only memory (ROM) to reduce hard- year and a half ago I wrote nounced equipment, but I find haven't, just pick up nearly any ware. A an article for SCCS Inter- that most people entering the back copy of any computer face fAagazine comparing the exciting and mobile field of per- magazine starting last July Of course, others, such as eight personal computers I had sonal computing balk at it— (e.g.. Sheila Clarke's article in Dataworks, with its 5K of oper- bought, built, designed, rede- especially compared to today, the September 1977 issue of ating PROM, preceded the Jolt signed and debugged (or failed when you can walk into a com- Kilobaud). (and Altair) by nearly a to debug). At that time, the PET puter store and get products Right up to the present time year—but the accent was on a was only a gleam in its father's from maybe a dozen suppliers the big question has been: Can firmware operating system, not (Chuck Pettle) eye. Now I have on an off-the-shelf basis. Fur- Commodore produce what they a hardware trade-off. The 6530 one. thermore, you pay for them claim for the quoted price and mask-programmed chip, which At the end of October my PET next month on a credit card. still make enough money to combined ROM, RAM, COUN- arrived, three and a half months I continually hear the query, stay in business? To get some TER and I/O, was, in my opin- after the usual "$800 cash-up- "Is it worth it?" It is. The day official answers from them, I ion, almost as big a milestone front" type order that most of after I received my PET I took it wrote a two-page letter and in large-scale integration (LSI) the others required. Although to a meeting of the Valley Com- received a one-sentence reply progress as the microproces- two weeks tardy, it had a better puter Club and was barraged that contained an honest ad- sor itself... not so much as a record than any of the others, with similar questions from mission to "crummy documen- technological breakthrough except the Scamp and Tarbell, people who already had their tation." After this article was (competing devices had similar which arrived on time. I've own computers. How does it half written, I had a chance to technology), but as a practical come to accept late delivery as stack up? chat with Chuck Pettle, but the adaptation of an emerging technology to take a giant step a way of life for newly an- This "report card" is an at- opinions herein expressed are forward on the path of pro- times as much and used a 4-bit PROM) to get a resident assem- deposit of $800, the closest gress. word. bler, BASIC or both. An even competition providing similar Instead of needing a single The obsolete formats aren't more expensive memory alter- specs cost more than twice as board for a Teletype port (as on dead, yet. Heath took (in my native was, and is, the floppy much. The Radio Shack TRS-80 my Altair 8800), the whole Jolt opinion) a step backward with disk, with magnetic bubble is squarely in competition with took up less than half the real Octal I/O; my new Motorola devices warming up in the bull Commodore's PET, and the fac- estate. The forever-drifting ad- Educator II uses the single-bit pen. tor of vertical integration is like- justments of the Altair were format. All in all, KIM was in- On the software side, BASIC ly to keep the field small. Only a replaced by a ROM/l-0, which deed a big step forward in its has been evolving. Spurred by few companies, such as Texas measured the speed of my TTY time. the San Francisco community, Instruments (with their wrist- and adapted itself! But the real At the time KIM was in- in general, and Tom Pittman, in watch and calculator mass pro- value of the TIM (or Demon) troduced, several other I/O particular, the old original Dart- duction-marketing technolo- 6530 was the documentation. developments were also emerg- mouth BASIC was first freeze- gies), have the high-priced Here were 1000 bytes of I/O and ing. The highest impact devices dried to miniscule proportions chips to pay the entry fees into and then extended. But what is such a marketing race. Let's more important is the cost of take a look at what vertical in- good software. In the late 60s, tegration has done for the PET. "PET gets As in three categories- even moderate software sold MOS Technology started as for thousands of dollars per an independently financed vertical integration, good engi- program, with additional hun- splinter group from Motorola's neering and advanced technology dreds to adapt it to your 6800 development program, system. Contrast this with Tom with associated legal problems Pittman's Tiny BASIC at $5, (now resolved). The resultant Chuck Crayne's 6800 Assem- 6502 microprocessor started as bler or Ed Smith's Trace/Dis- a "cheap" 6800. It uses most of operating system available at were the full keyboard and TV assembler in the $10-20 the 6800 instruction set, but is power-up, and documented in display. The pioneering laurels bracket, and the stage is set for (in my opinion) severely ham- such a way that its subroutines for bringing the digital TV mass usage of computer pered by its lack of a double- could be (and were) used in display out of the high-priced power. Mask-programmable byte accumulator. This defi- every program I wrote. It also range (over $1000) and down to ROMs could utilize this soft- ciency is somewhat offset by served as a workbook for learn- where you and I could afford it ware at reasonable prices, but page zero double-byte indexing ing practical usage of the 6500 belong to Don Lancaster, who only if high-volume sales could capability, which I've never code. literally wrote the book on the amortize mask costs. really been able to master. The Jolt had one big disad- subject. As the demand for low- The time has come for an af- Others have, however, and the vantage—for practical pur- cost full alphanumeric key- fordable computer that does 6502, which seemed to come poses: I had to have a $1000 boards produced larger not require the fervent learning out of nowhere, burst onto the TTY for a $300 microcomputer. volumes, the cost came down. and application of hardware scene in the Jolt as a showstop- A third development was and software skills heretofore per at the 1975 WESCON show. Enter the KIM also underway—BASIC. High- required of a hobbyist. I personally feel that the real Vertical integration started level languages (including innovation was the mask pro- with the KIM. KIM used two BASIC) had been around for a Enter the PET gramming of the MOS Technol- 6530s to double the firmware long time, but, without full The third entry from MOS ogy 6530 I/O chip. In any case, and utility. It preserved the TTY alphanumeric I/O, the com- Technology (a fourth is on the MOS Technology was off and I/O of the Jolt but eliminated puter hobbyist had to work on drawing boards) is another running, nipping at the heels of the total dependence on the the bit, octal or hex level. This significant step forward for its the well-established Intel 8080 TTY. It had its own hexadecimal meant working only in machine time. At the time I paid my and Motorola 6800. keyboard, hexadecimal read- language if you had the mini- out and cassette storage to re- mum computer configuration, place punched tape. The single such as KIM, Scamp, etc. It board (plus power supply) KIM took only a few hours of "bit- outperformed three or four banging" with op-code conver- boards in my Altair and Imsai. sion to realize that there had to It was the end of the octal- be something better—probably binary (switch, LED, front BASIC or an alphanumeric as- panel) I/O era. Toggling data sembly language. one bit at a time with lever Even if you could afford the switches was popular in the extras to interface the neces- in I late 50s and early 60s. With sary keyboard and CRT (around f data in the 3-bit octal format, $1000 a few years ago), there L 111 i { « - 111 M 1111 • the numerical readouts, were other problems. On the K ||M» • ^ IIIIIIM*"' keyboards and printers of the hardware side, you needed III - liiiliiM late 60s and early 70s became memory—lots of it. You could popular. Although my PRO- use RAM, and wait and wait to LOG preceded KIM by a couple load BASIC or an assembler. of years in adopting hex (hexa- Or, you could pay and pay ($425 Photo 2. Front-runners: TRS-80 CPU and keyboard, left. PET's CPU decimal), it cost nearly ten for my ALS-8 assembler on and keyboard, right. As the price of 8080s and do for an encore? The Apple-ll MOS Technology (and Chuck shelling out the money) was, 6800s fell under $30, the 6502 and Ohio Scientific Machines Pettle), the PET was inevitable. "Can Commodore really do it?" lost its price advantage, but it had pushed the use of ROM The pieces fell into place. The Judging from the reaction of was staying ahead in other operating systems and hard- major expense items for an in- people I spoke to and the ar- areas—primarily the KIM. In- ware/firmware trade-offs right expensive computer were no ticles I read, the consensus of tel's Intellec and Motorola's Ex- up to the state of the art for longer the microprocessor opinion was that they couldn't. orcisor developnaent systems 6502. Something radically dif- chips (less than $10 in quantity) When the promised delivery ran into thousands of dollars; ferent was needed. nor the I/O chips, but rather the date came and went (with the KIM was less than $300. Al- I/O devices. The TV headed the same lame excuses I've heard though it didn't do nearly as Enter Commodore list, followed closely by the key- time and again, starting with much as the "biggies," KIM, As an early front-runner in board and cassette recorder. my first Altair) I, too, began to with its superb documentation, the pocket calculator revolu- The next generation of micro- wonder. As of December 1977, was an entry into the world of tion, Commodore faced the computers would require all of Commodore was slipping even microprocessors for the small- same overproduction, price these ... but was it practical? further behind in deliveries. er electronics manufacturer. cutting and market-saturation There was the spectre of Does this mean that they're Until very recently, the lack problems that had left a world- Sphere. Note the marked following in Sphere's shadow? of a good, cheap assembly wide trail of corporate corpses. resemblance between the Will my PET become another language and trace has limited Mits was almost one of these, brand new PET and my two- Sphere-like orphan—the Edsel my use of the 6502. The and we all know what saved year-old Sphere in Photo 3. The . of personal computers? I think availability of Chuck Crayne's them from disaster. resemblance is more than skin not, and here's why: PET gets assembler for use on the The microprocessor original- deep. The built-in TVs and dual As in three categories—ver- Sphere 6800 and Processor ly evolved from calculator tech- keyboards are obvious; not so tical integration, good engi- Tech's ALS-8 for the 8080 has nology—the field in which MOS apparent are the following: a neering and advanced technol- diverted my attention from the Technology also started. To- 10K ROM operating system in ogy. Let's see how PET mea- 6502. My biggest disappoint- day, the calculator field is the Sphere (14K for the PET); sures up to competition. ment with my PET is the virtual headed in two directions: the $5 36K RAM for Sphere (8K for Vertical integration is, nonexistence of the advertised cheapy and the $600 wrist- PET); PIA, dual cassette, TTY perhaps, the greatest asset. "system monitor." It might watch-calculator and/or the and modem for Sphere (dual The PET combines the past ex- have filled this 6502 assembler sophisticated programmable cassette, IEEE, PIA and TV for perience of product develop- void. printing calculator with long- PET). Making allowances for ment (Jolt and KIM) with the LSI Initial forays into a new field, term memory. How could Com- cost of RAM, PROM, etc., a semiconductor design and pro- such as microprocessing, are modore compete with Tl and Sphere that was roughly duction expertise of MOS Tech- usually on a small scale, so the others who had vertically in- equivalent to my PET would nology and the "offshore" sub- KIM filled the bill admirably tegrated to produce everything have cost about three times as assembly production and ag- (and still does). 6502s were "in-house," from LEDs and key- much. The problem lies in the gressive marketing methods designed into new products, boards to LSI chips? You fact that Sphere Corp. went Commodore developed for its and MOS Technology grew. It guessed it—they bought MOS broke about the same time the calculator line. added memory chips to its line, Technology. Commodore is PET was being announced. PET'S competitors have which included character still in the calculator business, The 4K PET was originally equal or greater assets in one generators as well as the 6502 but you have only to look at priced at $500, which promptly or more of these three catego- family. their stock-market history dur- rose to $600, then to $800 for 8K ries, but none can match the The Jolt and KIM were both ing the last year to see where (the only model delivered, so vertical integration of Com- blockbusters when they were the action is, or isn't. far). Even at $800, the question modore-MOS Technology. announced ... but what do you When Commodore acquired in my mind (particularly after Radio Shack's TRS-80 comes closest. They have the best mass sales setup in the world. They also have the only foreign supply expertise that can rival Commodore's. This is perhaps the most important prere- quisite for a cost-effective end product. The highly priced com- ponents of a computer system are: TV monitor, memory, CPU (central processing unit), key- board and cassette recorder. Competition and mass produc- tion have forced the costs of CPU production down to a point where, even if you're mak- ing your own microprocessor (MOS Technology's PET, Motorola's Educator II, etc.), only small reductions in end- Photo 3. Now-defunct Sphere, right, is very similar to PET, left. Note the combined l^eyboard, TV, product pricing can be realized. CPU, integral dual cassette controls and number pad. PET's cassette is built in. boards (see Photo 2). will probably hit 7 on the Rich- As the learning curve pro- ter Scale). gresses, the tables should turn and give the PET a clear-cut ad- The Keyboard, vantage over all comers. PET's Graphics and "Extras" in-house volume base for the Both the PET and TRS-80 6550 (4K, 5 V, static RAM) could have recognized that the family even make this chip a dark- appeal requires electronic : horse contender in the 4K mem- game appeal. This makes a TV i i , ^ ^; 1 ory field. In fact, I'm so im- and keyboard graphics manda- pressed with its performance "i ! • 1 tory and brings up the problem T1J Ur 5 11 (despite four defective chips) of keyboard and/or joystick in- ea r' cmi'' that I'm designing it into a put. Although both have graph- 6800-based controller system. ics capability, neither has a joy- The third factor in vertical in- stick (as does the Dazzler or tegration is marketing. In this Apple-ll). I'm sure that this will Photo 4. PET'S controversial "calculator" keyboard, with quasi- area, the small (often garage- become available in the future standard key placement and conventional calculator number pad. type) computer company is go- since both have expansion ca- Note variety of graphic symbols available with shift. Lowercase is ing to have a very, very rough pabilities to support a joystick. also implemented (see text). time in the next year or two. There is a basic difference in Radio Shack, with its massive the use of graphics in the PET All the other items involve the quantities of proprietary-de- string of franchised outlets, and TRS-80. The TRS-80 splits purchase of devices and/or signed high-technology hard- has a clear-cut advantage, and each character block into a sub-assemblies made abroad. ware from overseas is a major its parent company (Tandy) is decoded matrix like the The biggest item is the TV accomplishment. Delivery and opening a string of computer Cromemco Dazzler, Apple, etc. monitor. Most hobbyist com- quality control require on-site stores. The PET goes a different route; puter manufacturers gloss over monitoring, which necessitates In marketing, the PET is a it gives a unique graphics sym- this item Vi*ith phrases like, a truly international organiza- phenomenon, so far. The Com- bol to virtually every key on "Use your own television set with tion with established opera- modore calculators survived in both keyboards. This provides adapter (not supplied)." A tions in the Orient. a cutthroat marketplace; so a very large selection of fine- reasonable frequency for your Both Commodore and Radio this, along with KIM, gives the line picture elements not TV set mathematically limits Shack can do this ... but, can PET a solid foundation. It's achieved through the older the readability of characters to anyone else? This is probably been further augmented by techniques. It also provides 16 lines, 32 characters per iine, the most important factor in bringing in experienced person- unique game-playing symbols, caps only. vertical integration —it sep- nel from competitors in the such as the card characters of Most hobbyists soon find arates the men from the field. Any newcomer will think hearts, clubs, spades and dia- that this limitation, plus com- boys in low-cost, high-volume twice before going up against monds. Descending lowercase petition for time on the family production. It's possible that this kind of marketing competi- characters (with shift) for all TV, leaves little choice but to these two leaders could pro- tion—the blue chips in this alpha characters and reversing purchase a monitor. A commer- duce more cheap personal game are expensive. white-on-black to black-on- computers in 1978 than all their cial TV monitor with adequate Another factor—the concept white are also provided. competitors combined — and bandwidth for lowercase, long- of utility —sets these con- All this flexibility poses make money at it. Even with line displays can cost almost tenders apart from their prede- several keyboard concept and years of calculator experience, as much as the computer cessors. They are not aimed at design problems, since each however, Commodore is having (before it "grew"). In fact, I'm the hobbyist computer-addict letter key must display six dif- overseas production delivery using monitors that cost as market (although the impact ferent characters. How can it much as my PET. Inexpensive problems (as of December). On but adequate TV electronics the other hand, the TRS-80 is come from Japan, Korea, etc. having problems getting its full So does another major acces- BASIC underway. sory—the cassette recorder. PET'S vertical integration in- The competition now takes cludes LSI production by MOS on an international flavor, and Technology, and when the dust International is Commodore's settles down, this may well be middle name. Most of Radio the deciding factor. Initially, Shack's line of Realistic prod- the TRS-80 had an edge be- ucts are also imported, in- cause it was designed with LSI cluding the TV monitor and already in high production from cassette recorder, which ac- second-sourced suppliers. count for one-third of the cost MOS Technology has had to of the TRS-80 system. PET's cope with the learning-curve keyboard is also imported problems of getting their new (more on that later). LSI RAM and ROM chips into overseas production. These Speaking from personal ex- Photo 5. My Sphere's original alpha keyboard was replaced as perience, I can say the busi- two items account for most of shown. Note pasted editing and control labels on fronts of keys. ness of getting production the costs of the respective CPU Specialized timing controls at far left are not standard. be done economically? PET's used the hunt-and-peck meth- solution was, of necessity, a od for number pad entry, multi- connpronriise. By using two cal- ple key-control character and culator-type keyboards (for special character entry. Unlike which Commodore tooling was touch-typing, most of my pro- probably available) and chang- gramming is really hunt and ing the artwork on the anodized peck, and the PET is just about caps, they got an inexpensive (but not quite) as easy to use as (probably the cheapest in the the Sphere (see Photo 5). A pro- world) alphanumeric keyboard. grammer friend and one of our The alpha key arrangement is keypunchers both claim that only quasi-standard, but the PET'S keyboard drives them up separate calculator numeric a wall. But then, how many PET keypad Is standard. It is also customers are professional small enough for the cassette data processsors? mechanism to be mounted Photo 7. All of tl sette record, playback and erase elec- alongside It and still fit a I understand that the next tronics are on this ^ small PC card. minimum-size case. model PET will have a full key- board, but will cost a lot more. I Both keysets are mounted on could easily wire a $40 key- graphics mode, and ..quires a use with any program written in the same cost-effectively de- board to replace the original POKE 59468,14 to convert the BASIC. The clock runs off of the signed passive motherboard. —in fact, the original lousy display to lowercase. A POKE 8 MHz crystal. Since the keyboard matrix alpha keys on the Sphere 59468,12 returns to graphics. Although it isn't immediately plugs intotheCPU with a single shown in Photo 5 have been re- This is accomplished by some evident, the real-clock function cable (see Photo 2), it would be placed, just that way. Then mysterious hardware/software Is an excellent example of the possible to use a standard- what would I do about the 70 manipulations involving a PIA aggressive design policy that spaced keyboard in parallel graphics and special charac- and ROM that I haven't deci- makes the PET a technical step with, or instead of, the forward, regardless of price. I calculator board. haven't figured out exactly how The most commonly criti- they did it . . . but what I've cized feature of the PET is the deciphered so far Indicates an key placement of the keyboard. "Except for the TRS-80 and PET, cas- impressive utilization of the Keys are more closely spaced latest LSI capabilities from than normal, the middle row sette recorders are a hidden extra MOS Technology (more vertical isn't staggered, and the feel of expense of personal computing." integration here, and a valuable a calculator key isn't the same feature not available from their as that of a typewriter (it's more competitors). Among other like a Teletype). I was told (by a things, the Tl (time) function is TRS-80 booster) that it Is im- a fundamental building block in possible to touch-type on the ters that aren't available as phered, yet. You can't mix automated home program- PET. He was wrong; however, it standard key tops? In short, lowercase and graphics. ming. Since it runs on inter- does take a relearning period, PET'S keyboard If I't great, but Changing modes changes rupts, It will keep the time of much like going back to a stick neither are the practical alter- every shifted character on the day as long as power is left on. shift after driving an automatic natives. screen, but not in memory. It But, unless you trim the for years. Another quirk of the PET is can create some weird effects oscillator, you'll have to keep When I returned to my full that its graphics and lowercase that I used to change graphics readjusting the readout. keyboards on the Sphere and display modes are mutually ex- each second in an experi- Imsai, I realized that I've always clusive. It initializes to the mental STOPWATCH program. PET didn't list its lowercase The Recorder System capability in specifications at By now it should be evident the time I bought it, so it came that the PET's low price was as a pleasant surprise—one of not achieved by making a cut- several "extras." down, stripped version of older A real-time clock is another technologies. Take the built-in of these extras. It doesn't do as cassette recorder, for instance much as an S-100 real-time (Photo 6). In all my other sys- card, but It doesn't cost an ex- tems, built-in recorders are not tra $130, either. It outputs a six- provided. Except for the TRS-80 digit, 24-hour clock word, e.g., and PET, cassette recorders Tl$ = 235959 = 23 hours, 59 are a "hidden" extra expense of minutes and 59 seconds. At personal computing. The gar- 240000 it resets to 000000 and den-variety cassette recorder is software presettable. It also isn't optimized for digital re- outputs JIFFIES, which are 1/60 cording. It sacrifices signal-to- second counts accumulated noise for Idw harmonic distor- from 000000. JIFFIES are about tion and ignores phase distor- Photo 6. Gutted cassette is probably a stopgap measure. Note as fast as anything you could tion. Its electronics are an absence of usual electronics, speaker, jacks, etc. overkill, Including automatic mat for all PET users. There is most cost-effective digital itor (such as the TRS-80) and gain control which prevents no problem in interchange of recording system I've analyzed, still provide the same legibility full-level recording. original recordings, only dupli- although the Educator II is a —another saving. cated copies. close second. It's an A -i- exam- PET'S cassette takes a radi- There is only one external ad- ple of saving money with de- cal departure. All the erase- I really notice the absence of justment: contrast. My PET sign ingenuity. record-play electronics are on a counter on the cassette re- needed vertical centering. It the single card shown in corder. Unless you restrict your was done with the black tabs The TV Board Photos 6 and 7. Obviously, the tapes to two or three per side, on the neck of the CRT. A small All of the other competing gutted mechanism in the cur- you wait forever for the pot at the rear adjusts the computers with CRTs use off- rent models is a stopgap solu- playback to find the right pro- height. So far it has been very the-shelf monitors or TV modi- tion to overseas delivery prob- gram. In desperation, I use a stable and provides a steady fications. In this instance, as lems, and the eventual recorder separate recorder to find the picture with a superior band- with the recorder, PET breaks should be produced at a signifi- approximate start position with width, another A-rated example with tradition, gaining im- cant savings over competing a counter and then transfer it to of cutting costs with creative proved cost/performance by re- systems. the PET—a real pain. Although system design. placing hardware with firm- the baud rate is high (1100 The recording method is a ware. The complex sync sig- The CPU Board baud), a long preamble, double- compromise between dc nals, which use up hardware in buffered recording scheme and Photo 8 shows the CPU saturation digital recording both the traditional character a motor stop between files slow board—PET'S brain. It takes and the frequency-shift-audio generators and monitor, are down the file handling to a less than two minutes to techniques currently in vogue. generated by firmware and the snail's pace, compared to a remove it. Wiring harnesses Dc erase is used, and square very powerful 6522 I/O chip. The Tarbell. The second cassette cost n >ney. Both the PET and waves are fed directly to the video, horizontal and vertical port is fully Implemented on the t e TI.S-80 keep them to a record head. The record current drives are also available on the CPU but, as yet, no recorder is minimum. The board plug is limited to prevent complete rear user terminal. Because the available to make use of it. I connects to the power supply saturation and biased for video board doesn't need to hope it will have a counter. keyboard, video and recorder centering. On my unit this decode sync or amplify video, Incidentally, be careful with the results in about 8 db better Another nice added "extra" it's simpler (and cheaper) than keyboard plug. Mine became in signal output on playback with is the verify mode. After record- competing models. Since the termittent after its first replace- improved phase distortion ing, you can rewind and verify screen is built in close to the ment. The leaf spring contacts characteristics. My unit also the tape playback against operator's eyes, it can be in the female cord connector had two dry-joint solder inter- memory. Since I've eliminated smaller than a separate mon- are easily overstressed and mittents. the intermittents in the record- To find these, I had to create er, it's a bit redundant because a schematic. I also needed the there has never been a play- Information to find out why my back error. PET played back its own tapes Another extra is the unri- flawlessly, but couldn't copy valed simplicity of loading a from one cassette to another program—turn on power, insert as I've been doing with my a cassette and press RUN. It Sphere, etc. The problem was in tells you to play the recorder, the reduced record level and displays the label of the first phase distortion. It worked thing it finds, tells you it's most of the time, and might loading and if it loaded OK and even be practical for short pro- runs the program. Even a very grams, but it certainly isn't small child can do it. An A good enough for longer ones or rating. If children are to realize file storage. PET got some the maximum educational po- demerits when I found that tential of personal computing, several playback errors were this approach will be very help- not caught by the double- ful. If you specify a label, it will recording check. I'm sure that a display each label it finds until mass cassette duplicating it gets the right one—then operation will eventually loads it. duplicate digital tapes in this The PET'S recording format format, but my copy of the first is unique, like those of most of one on the market {not Com- the new computers ... it looks modore) was a disaster. as though the Kansas City I asked Chuck Pettle if PET standard will bite the dust. The was designed that way on pur- PET maximizes the hard- pose to give Commodore an ware/software trade-off. It uses edge in the prepackaged soft- almost a bare minimum of analog devices (room for de- ware field. He was surprised at Photo 8. PET'S brain: Top 16 chips are RAM. Seven ROM chips my difficulties, and assured me sign improvement here), a cou- beiow contain operating firmware. Power supply and cassette #7 that the intention was to pro- ple of PIA ports and no UARTs are along right side. Output ports are along bottom (rear). BUS and vide a truly interchangeable for- or other serial l/Os. It's the memory expansion are at left. may have to be re-formed with a had four failures), you'll need to probe. play musical chairs, since it's Note how the four expansion impractical to apply a memory connectors are made directly test to the low 1K where BASIC to the board through slots in operates its scratchpad. This the side and rear of the case—a device gets an A for design and far more efficient arrangement a D for deportment. than that of any of my other The ROMs in the first units systems. At this time there is (mine included) were not the nothing available to connect to MOS Technology devices cur- them, but when there is, the dif- rently being shipped. They are ference between the utility of 2K devices and are now being the PET and the TRS-80 is likely soldered in. Although PET is of- to give the PET a big com- ficially specified for 14K of petitive edge (see Photo 2). ROM, 2K of the same ROM is The long connector on the used as a character generator. left-hand side has what the The PET is currently oriented TRS-80 has on its single expan- toward the personal-computer sion port. In addition, the ad- mass market; changing only dressing is available decoded the ROMs and keyboard caps into 4K blocks. Current plans could make it a super develop- call for its use in RAM, ROM ment system, smart terminal, and PROM (2716) expansion. dedicated controller, word pro- The monitor and assembly lan- cessor, typesetter or just about guage will probably go into anything micros are, or will be, ROM. used for. It could happen vir- tually overnight, and, with the The current price of $200 for inherent mass-production 4K of RAM makes PET about Photo 9. The power transformer, filter capacitor and 110 ac control economics, it would be a price- the highest-priced RAM on the are the only electrical devices directly wired to the chassis. cutter in any market. (That's market. When the 6550 moves awesome when you think about out on its learning curve, PET Packard) available for use with sinks are the motor controllers it, since MOS Technology could should be in a position to pro- the 488. However, most of them for the cassette recorders. The supply inexpensive masked vide the cheapest memory cost more than the PET and are regulators are running hot now, ROM for any application.) around. special-purpose test instru- so additional loads should be The small connector pad in ments, not really suited to per- limited. Mechanical Engineering the lower left corner is for sonal computing. Motorola and The 8 MHz crystal clock PET gets a B+ for its metal cassette #2. You can play the others are coming out with LSI drives the 6502 microprocessor case. It will probably be re- recorder into it. It works, but, as chips that should make the 488 atl MHz. It also provides theTV placed by a more durable plas- yet, there isn't any recorder system cost competitive with timing and 60 Hz JIFFIES. The tic case, but dies for this size available to use with it. If PET the S-100. This won't happen crystal is stable, but the factory molding are a long time com- doesn't make one available immediately, but when it does, feels that plus or minus IVz ing. In either case, the PET is soon, I'm sure someone else PET will have a well- minute per day is adequate. If utilitarian and its exterior ap- will, and I hope they provide a established lead over the rest you want greater accuracy, pearance can only be com- counter. The center connector of the pack, particularly in soft- you'll have to trim the driving pared to units costing several brings out the aforementioned ware. PET gets an A here be- capacitors next to the crystal. times more. It even has a prop video feeds and half of the cause Commodore's vertical in- A 6-30 pf variable in parallel to hold up the hinged top for powerful 6522 PIA program- tegration should allow them to with 22 pf did the job for me (see servicing. The tooling is a little mable I/O. It's called a User port make inexpensive peripherals Photo 10). Now I can trim it like sloppy and some of the holes and, if documented adequately, that could be used with com- my digital wristwatch. The are mismatched. My degree could become PET's most petitors' microcomputers, as 24-hour clock is counted with was in mechanical engineering valuable asset. well as with the PET. The interrupts and should be soft- (a long time ago), and I ap- The lower right connector is TRS-80 (see Photo 2) with its ware independent. I've en- preciate good mechanical de- the lEEE-488 bus. If and/or single, unique 40-pin port only countered unresolved prob- sign. PET has it. Not only is the when the S-100 bus system rates a D when it comes to this lems with a program that con- case impressive, but so are the yields to another format, it's kind of expansion. tinuously reads Tl$—it speeds circuit-board layout and the up the displayed time. likely to be the 488. This system PET'S power supply, see overall cost-effective design is supposed to allow your PET Photo 9, is 5 volts only (Sphere The 6550 RAMs are 4K, high decisions. Three of the four cir- to talk with up to 18 peripherals uses five different voltages) for speed, low power, static, and cuit boards are inexpensive through a high-speed, 8-bit the digital equipment. The TV require only 5 volts. They are "single sided." parallel bus. Properly im- board has its own rectifier-reg- pinned as IK by 4 bits, so they The case of the TRS-80 is a plemented, it can be almost as ulators. The CPU board splits are socket-mounted in pairs good design job also, but the fast as a motherboard or back- the load into three sections along the front of the board. overall effect looks like a key- plane. with the three 5-volt regulators Page 0 is at the left and the high board with dangling wires to a There are more than 200 along the left-hand side. The nibble is toward the front. If dominating TV, with a cassette devices (a lot from Hewlett- two power transistors with heat memory problems occur (I've and power supply strung around it. The TRS-80 is more nor your local dealer can use it: Pettle, that most warranty sign objective. Currently, there attractive than the uncased it's a factory secret. Now what repairs took less than a week, if are two flaws in the grand plan. Jolt or KIM, but, to the average do you do? worse came to worse. All available parts are being neophyte, it may not look like a First, call the factory. When I OK, so my PET is running used to try to satisfy a huge computer when compared to a called, the girl who answered pretty well, but what about the backlog of delinquent system PET or Sphere. didn't know what I was talking housewife In some boondocks orders. There are no spare about, and the fellow who town without a well-equipped boards for dealers or service- And Now ... might have known was unavail- laboratory, years of experience men. Also, documentation and The Bad News able. People who went through or a WATS line? What if she got test equipment are not yet PET gets low marks in two this with Mits and SWTP in the my #171? Well, as of December, available in what Chuck Pettle areas: reliability and service "old" days (it's changed now) her only recourse would have describes as an "acceptable" maintenance. I give it a D. At know the script. been to return it to California or form. the same time, there is enough After a period of fuming and Pennsylvania and hope that When 1 asked him when 1 room for improvement so that it fretting, punctuated with ex- Murphy's Law, as applied to in- would get schematics ade- could go to the head of the pletives, I decided that $10,000 termittents, wouldn't require quate for servicing the prob- class. It worked when I received worth of test equipment and too many return trips. However, lems with my PET, he told me it. Since then, I've had four in- four years' worth of experience by the time you read this, PET that only the characteristics of termittents; three were bad with microprocessors ought to could be in the best service the I/O were going to be re- solder joints and the fourth was be able to solve the problem position any personal com- leased. and the rest would be a defective connector. I have without schematics. It did puter manufacturer has ever kept "secret from competi- also had four memory failures, —partially. been in. tors." In a vain attempt to get a glitch in my TV horizontal I had to write my own mem- The information and special him to change his mind, 1 sweep, drifting vertical center- ory test program and use a wiring harness should be pointed out that a competent ing, undetected read errors, off- multitrace storage scope to released so that the built-in computer engineer could pro- frequency crystal calibration eventually find the intermit- diagnostics can be utilized by duce a schematic of the whole and a couple of other weird tents and some of the bad relatively inexperienced peo- system in a few days and that goings-on that remain uniden- memory chips (also intermit- ple. Faults could be fixed by any programmer who has writ- tified. To put things into per- tent). Then, another call to the identifying and exchanging the ten a BASIC interpreter (see "A spective, I should add that this factory. This time 1 was put offending circuit. Since there Tale of Four BASICs," Kilobaud behavior is better than that of through to the right man with are only four circuit boards and No. 13, January 1978) could pro- my Mits 8800, Mits 680, Imsai, the right attitude and right a rudimentary power supply, duce a source listing of the Sphere, Jolt or SWTP. answers—a real gem. Three the built-in diagnostics, aug- ROMs. In fact, the only firms Bugs are a way of life when days later I had replacements mented by test cassettes, that possess these In-house you get the first units off a pro- and spares, no extra charges, should easily bracket the skills are his competitors\ As duction line; I expect them. no insistence that I relinquish problem. they say about gun control, "If Mits had trouble with bad mem- my cherished PET for an in- From personal experience, you make gun possession a ory chips on the first 8800 definite stay and a lot of good I'd estimate that most "while-u- crime, then only criminals will boards . . . worse than my solid advice on how to tackle wait-repairs" could be done in possess guns." If PET (or Radio PET'S. They wouldn't send the remaining problems. He less than 15 minutes. The abili- Shack) refuses to supply sche- replacement ICs so I reluctant- also assured me, as did Chuck ty to do this was obviously a de- matics to servicemen and pro- ly sent the useless boards duct designers, then the only back. It was four months and people who can get the infor- $40 extra before I got working mation are their competitors memories from them. with skilled manpower. The big hang-up with bugs in my PET is that there is no ser- I admit I'm biased by the vice information provided; fur- many wasted hours I've spent thermore, it's unlikely that I'll debugging my PET, but I can't see a schematic for a long, long help feeling that Chuck is time, if ever. The local dis- adhering to a shortsighted tributor doesn't have any more policy. However, I feel that he's information or spare parts than a reasonable man, so I hope I do. The 6550s aren't on the someone else will succeed market and there are no com- where I failed, and we'll all plete spec sheets available benefit. for them. A magazine article After rereading what I've just had estimated that factory ser- written, it's evident that, with vice would require two months, the exception of the service including shipping. If you and documentation problems detect a note of frustration, (which may not exist by the you're right! It's even worse time this is printed), the PET when you see a little LED on the has been depicted rather posi- board and know that it's a part tively. As a matter of fact. Com- «f a built-in diagnostic system Photo 10. Author's modification of 8 f^Hz crystal oscillator with modore could easily drop a per- that's using up some of the trimmer capacitor trims 24-hour clock to high precisiort, but soft- haps fatal wad on the PET ven- ROM you bought. Neither you ware problems remain. ture. Several local dealers who were pushing PET a month ago them. I'm betting that PET will act as delimiters. If you're used system that consists orV3D, are now telling customers to have a similar success. to using abbreviated instruc- PDS, Mason's X-DBUG and Pro- buy something else because When it comes to software, tion, you'll be disappointed. gramma Assoc. text editor, it "Commodore is going broke." I PET gets a C, with an "in- The original specs called for would require 20 percent less suspect that delinquent deliv- complete" noted in the margin. a 4K basic operating system. ROM and provide many fea- eries and "cash-up-front" The bare-bones listing of Micro- Compared to my Sphere operat- tures not found in this version dealer policies are the real soft's latest BASIC makes it dif- ing system with only 2K of of the PET. This includes utility motivation, but how much of subroutines such a number- this can PET take? base conversion, multibyte divi- One look at the gutted cas- sion and multiplication, block sette recorder implies a big "If PET refuses to supply moves, hex-decimal-ASCII con- problem with overseas sup- versions, etc. plies. Less obvious, but un- schematics to servicemen and mistakable, evidences abound designers, only competitors Conclusion to attest to the probability that After all the pros and cons my cold-solder-joint intermit- can get the information. " have been considered, it looks tents are the result of question- to me as though Commodore's able production practices and PET has the brightest future of relaxed, or inadequate, quality any microcomputer I've ever control. ficult to work with, much less PROM, the PET is a disappoint- evaluated. It could graduate No matter how cost-effective evaluate. Someone else will ment. There are USR and SYS summa cum laude. Right now a product design may be or how have todo that afterthemanual commands in BASIC, but no it's on shaky ground and could dynamic the pre-production is published. So far it's about facility to load or generate conceivably flunk out, as did sales effort, if you can't pro- the same as the Crayne BASIC machine code except by writing the Sphere. It could have the duce a reliable product on I've been using on the Sphere your own program to POKE it in short-term success of the schedule with efficient and and the Mits on the Altair. It's BASIC. I had hoped that they average microcomputer, such minimal after-sales service, faster, the error messages are would at least start where the as the Jolt. No matter how you'll lose the ball game ... re- better and the files are double two-year-old Sphere system left history marks its final report member Viatron? MOS Tech- buffered, but watch out for off. card, a new era of mass usage nology had problems with the commas within quotation If I were to put the Crayne's of artificial intelligence has early KIMs (mine went back marks, such as addresses in Sphere BASIC in ROM along been ushered in by Com- twice), and successfully solved FILE programs—they tend to with the current ROM operating modore's PET.B "^"l^^ucts that makVyourcoinputCT EXTEND... CONTROL! CA'Vf '•"•A Whether for troubleshooting or analysis, if you have an The Altair/S-100 compatible Relay/Opto-Isolator Control S-100 machine at some point you will need our Extender Board Kit (S117) is a natural for controlling audio systems, Board with Logic Probe Kit ($35). The logic probe makes it lime lapse photography experiments, model trains, robot easy to see which signals are going where . . . our special devices, or any application where you need a number of in- edge connector provides easy clip lead probing, jumper links telligent switches . . . more uses are discovered daily, as in supply lines allow for fusing/current measurement/shut- detailed in our applications notes. 8 reed relays respond to an down independent of system, and a non-skid needlepoint 8 bit word from your computer; 8 opto-isolators accept an 8 probe helps prevent accidental shorting. As with other bit word from the outside world and send it back to your Mullen kits, you also have quality parts, detailed instructions, machine for handshaking or further control purposes. In- and a realistic price. cludes detailed instructions. y Available by direct mail MULLEN COMPUTER (shipped ppd. in USA from board"^ stock; Cal res add tax) or at I many fine computer stores. 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FEATURES PRINTER or TYPEWRITER PRICE and DELIVERY • Complete ASCII character set • May be used as a standard • Assembled and tested, S1750 in supplied element. typewriter when not in use • Available ONLY from author- • Full upper, lower case alpha- with your computer. ized dealers. numeric characters. • Delivery 1 to 2 weeks from • Tab Command, Index (verti- receipt of order. cal tab), Backspace, Bell-all OPTIONS • OEM delivery in quantity within under computer control. • Dual Pitch, $125 • Parallel Interface, standard. • Correction Feature, S125 30 days. • Tractor Feed Platen, $250 • Noise Reduction Feature, $50 ALL ELECTRONICS INCLUDED • Power supply, electronics and cable sets included to permit AVAILABLE SOON micro immediate connection to the • RS-232 Interface parallel port of any computer, computer at standard TTL level. devices SOFTWARE inc. • All necessary conversion soft- 960 E. Orangethorpe, BIdg. F ware in PROM to handle Anaheim, California 92801 ASCII input, directly. Telephone (714) 992-2270 •Registered trademark of IBM Corporation M30 "Innovators to the Microcomputer Industry" Bob Buckman slightly more expensive). 3954 Hillview The scope I bought is the T922 Santa Maria CA 93454 —a dual-trace, 15 MHz band- width, portable instrument that tips the scales at a mere 15 pounds (see Photo 1). I ordered it from stock by telephone from my local Tektronix Service Scope Power! Center and mailed a check; two weeks later, UPS left it on my doorstep. Ah! Nothing beats the joy of opening a box with Tektronix printed on the side! It was packed securely with air space all around and contained a review of Tektronix's Model 922 a manual and two $42 list-price X10 attenuation probes (includ- ed in the price—$850 FOB Bea- verton OR —you thought I wasn't going to tell you). It worked perfectly; that's one ad- vantage of buying an assem- ektronix's motto is "Com- center, to troubleshoot your facturing shortcuts. The scope bled instrument. mitted to Excellence." That hardware. Read on for a short is literally built around the T I was surprised at the length motto, and the resulting equip- course in scopes. scope tube. The huge 8 x 10 —almost 19 inches, most of ment, prices most of Tektron- Tektronix has always been centimeter square screen with which is scope tube ... I ix's products out of the hob- the Cadillac of the industry, internal graticule on the front couldn't resist looking inside. byist range. In 1976, Tektronix with appropriate prices. The of the display won't rotate out The plastic case comes apart announced the T900 series of great thing about the 900 series of place, rub off or fade with after removal of six bolts (see oscilloscopes. Finally, a Tek is that the basic design is the age. With the nominal 12,400 Photo 2). Most of the acton oc- scope 1 could afford! Last June same as for the top-of-the-line volts dc acceleration potential, curs on two single-sided circuit I purchased a medium-priced scopes. Why should you buy the dot size is small and the boards. The pilot light is a neon T922. this scope? What features put writing speed fast. NE-2 with a light pipe guiding You software types should the 900 series above all the The least expensive scope the way to the front panel. Most know what an oscilloscope is. others in the market? in the 900 line is a single-trace knobs are extended with plas- It can display little squiggly instrument that sells for $650. First, the scope tube itself. tic rods to controls positioned lines to enable you, or your All the others in the line are the Designed and constructed by toward the rear of the circuit friendly neighborhood service dual-trace variety (and only Tektronix, it contains no manu- boards. The attenuators, since they are of unique stripline de- sign, are mounted on the front panel near the BNC input con- nectors—altogether an easily assembled, well-planned lay- out, with room for expansion (see Photo 3). I may add the T935 delayed sweep features as soon as I get the other scope manual. The 15-position calibrated at- tenuators are constructed us- ing the same stripline cam- switch techniques from the 500 MHz mainframe machines. With steps from 2 millivolts to 10 volts and a variable control over a 2.5 to 1 range, any volt- age can be easily displayed. The 912 and 922 calibrated time base has 20 steps in a 1-2-5 sequence from 0.5 second to 0.2 microsecond per centime- ter. With a variable control from IX to 10X, the maximum sweep rate is 20 nanoseconds per Photo 1. The complete system. centimeter! things bothered me. First, the chop and alternate sweep mode is selected internally by the sweep-speed switch in the T922, but the rack-mount ver- sion of the same scope has a front-panel switch! I know that the chop mode isn't very useful above half a millisecond per centimeter, but sometimes it is essential for single-shot events and I can't get to it. Frustrating. The second thing is a feature you don't really think about un- til it is time to take a scope photo: a scale illumination. It would require front-panel rede- sign and add at least a hundred bucks to the price, so I accept the lack of scale lighting. The rack-mount version does have scale illumination and takes any 7000 series scope camera —it also costs more. If you're deciding on a scope, consider the Tektronix 900 Photo 2. The tube determines the scope's length, Photo 3. Most controls are extended (left side series. Why not the best? I width and height (right side view from front). from front). know my scope is one of my best investments. A card to Frequency response? Oh will fit on the screen no matter I paid for It. Tektronix's world- Tektronix, PO Box 500, Beaver- yeah—dc to 15 MHz for the 912 where the position controls are wide reputation is simply the ton OR 97077, or a call to your and 922 (my scope), dc to 35 set. Once you've found the standard of excellence. local Tektronix representative MHz for the 930 series. That's trace, set the controls for best This report has been flatter- will result in your getting order- minimum, folks! The top trace position and release the mo- ing. What didn't i like? Only two ing information.! in Photo 4 is an 8080 phase 1 mentary beam-finder button. clocl<; the bottom trace is The balanced delay line (the phase 2. The slight ringing on looped cable in the center of the low side of the phase 2 Photo 2) slows down the input clock is due to a bad ground to signal so the sweep starts be- the scope probe (see Photo 4). fore the display—you can see Triggered sweep assures the part of the signal that that the sweep does not start started the sweep. No more until the triggering conditions guessing what the leading are met. This allows you to easi- edge looks like! ly measure single or repetitive The manual provided with pulses, which will always show the scope is a work of art. It's up at the same place on the actually a scope textbook all by screen. You can select the posi- itself: 20 pages of operating in- tive or negative slope of the structions, five pages of per- waveform and, by varying the formance tests to let you know trigger level, trigger anyplace if the scope still meets its spec- on the waveform. Auto trigger- ifications, 31 pages of service ing, alternate or chop mode information to help you fix (dependent on sweep speed), whatever might be wrong, at TV field or line sync, external least 50 pages of fold-out block sweep and X-Y modes give you diagrams and detailed sche- any combination of triggering matics, complete exploded modes you need. views of all mechanical parts Ever lose the trace? You with a detailed parts list for know the signal is there but the everything —truly a joy to dc level has moved it off the peruse. screen somewhere. Simply de- Did I say anything about re- press the beam-finder button. sale value and reputation? Ten The display will be squeezed years from now, I could sell this vertically and horizontally so it scope for nearly the same price Photo 4. 8080 docks 200 nanoseconds per division. r J rA . i SEE YOUR LOCAL k^/jfi DEALER TODAY . . . rro meg ALABAMA Huntsville Computer Land ARIZONA KANSAS Phoenix Bits & Bytes Mission Computer Center - Byte Shop No. 61 Tempe Byte Shop Wichita Computer System Design Yuma Ozymandias Systems KENTUCKY CALIFORNIA Louisville Cybertronics Santa Ana Advanced Microcomputer Products Louisville Data Domain Costa Mesa Algorithm Personal Computers LOUISIANA Hawthorne Applied Process Laboratories Downsville Bill Gulledge San Rafael Aaron Enterprises MARYLAND Long Beach Avido Electronics Towson Computers, Etc. 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Electronics Cincinnati Cincinnati Computer Store Anafieim Micro Computer Center Kent Ohio Microsystems Santa Monica Mission Control Cleveland Tec Mar, Incorporated Sherman Oaks Peoples Computer Shop OREGON Redondo Beach Personal Computer Center Beaverton Byte Shop - Beaverton Torrance Randal Data Systems Coburg Forethought Products Bakersfield R & H Electronics Aloha Kent's Komputers Scotts Valley Success Systems Eugene The Real Oregon Computer Co., Inc. San Gabriel Sunny Sounds Carson Sunshine Computer Co. PENNSYLVANIA Tarzana Tech-Mart King of Prussia Computer Mart of Pennsylvania San Diego The Computer Center Huntingdon Valley Marketline Systems Orange The Computer Mart Pittsburgh The Electronics Place Santa Monica The Computer Store SOUTH CAROLINA West Lake Village Vector Graphics, Inc, Columbia The Byte Shop No. 32 COLORADO TEXAS Englewood Byte Dallas Altair Computer Center of North Texas Boulder Byte Shop Houston Andy Electronics Company, Inc. 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Atlanta Byte Shop Forth Worth Tandy Computers Atlanta The Computer System Center Richardson The Microstore HAWAII Houston The Computer Store Honolulu Mahalo Microsystems, LTD College Station Young Electronic Service ILLINOIS TENNESSEE St. Posen Bits & Bytes Computer Store Nashville Computer World Champaign Champaign Computer Company UTAH Harwood Heights DMA, Incorporated Provo Computers & Stuff of Utah Evanston Itty Bitty Machine Company VIRGINIA Skokie Lillipute Computer Mart McLean Computer Systems Store Lombard Midwest Microcomputers, Incorporated Newport News The Home Computer Center Oak Park The Computer Store WASHINGTON INDIANA Seattle The Retail Computer Store South Bend Audio Specialists WEST VIRGINIA Bloomington Data Domain Morgantown The Computer Corner Incorporated Indianapolis The D??ta Group, Incorporated WISCONSIN Indianapolis The Home Computer Center Sheboygan Falls DMA Incorporated TARBELL SETS STANDARDS For Hobbyists and Systems Developers Sales to thousands of hobbyists over the past two years have proven the Tarbell Cassette Interface to be a microcomputer industry standard. 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Tom Badgett 1917 Washington Street Blue field WV 24701 Trials and Tribulations one businessman's micro biues smoky hqijhtwh « T ft'X'ACO Smoky Mountain Aero. With about $200,000 per month in aircraft loans—not to mention gasoline sales, service, instruction, charter, rentals, tie-down and advertising—SMA uses a lot of business computer power. ou see, I never had any in- microcomputer user. He was a with a Maryviiie bank, but the make a potential microcom- Ytention of using my micro radio-station engineer and micro handles mailing lists and puter user fold up his memory In my business; I just wanted it owned an avionics service letter writing, aircraft tie-down cards and quit. On the other to play with," Jim Sexton tells facility—among other accom- and maintenance records, air- hand, the Smoky Mountain folk me. I was surprised because plishments—before taking over craft insurance, advertising have a far-reaching view of the other people had said Sexton's Smoky Mountain Aero, one of and sales duties. A second Mits micro business. With this tone Maryville, Tennessee, flying the largest aircraft sales-and- system is in the works. of ambivalence in mind let's service uses a sophisticated service operations in eastern Choosing hardware wasn't start at the beginning. microcomputer business Tennessee. He still maintains easy; writing software is a con- system. his avionics shop and offers tinuing, frustrating job; keeping Software Problems flight instruction and charter the machines on line is a big Never one to do things In a "When I found out you could service besides. headache. Even so, the com- small way, Jim Sexton visited do some useful things with it," Smoky Mountain Aero's puter system is performing various manufacturers and he continues, "I moved the unit primary micro system Is built useful tasks for the business. retailers around the country, from home out to the airport. I around an imsai mainframe "We've got enough stuff on it flying to all the major cities in kept expanding it, and the next with Seals memory, a PROM so we couldn't do without it the East and Midwest for equip- thing i knew I couldn't take It board, Mlts disk drive, a Lear now," Jim smiles wryly. ment demonstrations. The back home anymore." Siegler terminal and an LA-36 But, in spite of the smile, the results were less than satisfy- Jim's background in elec- DEC Writer. Smoky Mountain Smoky Mountain Aero story is ing. He settled on an early tronics made him a natural still shares a larger computer depressing at times, enough to Altair, then because of power supply limitations, bought an more than a novelty appealing Imsai. Hungry for information only to inveterate experiment- to turn his new toy into a useful ers and hobbyists. business tool, he continued Jim has a strong electronics visiting suppliers. background, remember, but Due partly to a lack of soft- each time a glitch develops he ware and apparent equipment has to go to Mits or Imsai for problems, Jim began buying help. Engineers and program- more hardware—a Processor mers naturally want to know Technology SOL, lots of which memory locations he's memory, disks, etc.—but final- using, how his software is con- ly settled on the Imsai/Mits figured, etc.... questions that system he's currently using. only increase his frustration The big problem was, and is, level. getting useful software to run "When I bought the com- on this system. puter I didn't take time to learn "I haven't met anyone in my about memory locations and travels—with the exception of octal and hexadecimal and all Altair Software In Atlan- this stuff; so they'd have to tell ta—who knows what they're me on the telephone which doing," Jim recalls. Even Altair switches to push, what to hit Software Distribution has its next. Then I'd read the panel problems, though. In Jim's six and tell them which lights were visits to buy a word-processing lit, and they'd tell me what they package, the Altair Software thought was wrong." people were unable to show Some recent hardware ad- him one that worked without vances—cheaper memory, file-link errors or disk-drive ROM programming, better disk problems. "Every time they'd systems—perhaps have eased try to demonstrate it, the thing some of the problems Jim suf- Jim spends at least $500 per month on outside computer services would switch off and come up fered through in the beginning. from a local banlt. He gets printouts like this every two weeks to with some kind of error. They've Systems like the Commodore help keep track of aircraft loans, business profits and tax infor- never been able to demonstrate PET and the Radio Shack mation. The printouts also list aircraft operating records, main- a working package to me," he TRS-80 are welcome entries to tenance information and pilot time. He'd like to use his own says. the computer field, but Jim Sex- microcomputer for daily information, but he can't trust it. ton still believes the micro in- Jim tried several books of dustry is too hardware oriented programs, advertised to fill a ness. "Sometimes it is very Aero pushed the price up in a and suffers from a hobbyist plethora of business and hobby hard to know what each sale hurry. mentality. needs. He and his secretaries actually costs." "Over the years, the big com- spent hours keying in the "The problem has been," he Jim believes a computer sys- panies, by withholding technol- printed programs, only to dis- says, "that the micros have tem that worked, coupled with ogy, have been able to sell a cover that none worked proper- been designed for the ex- a reliable software package commodity at a very, very high ly. Based on a close analysis of perimenter—where cost is a could encourage more people price," Jim laments. "But what two of the programs—Depreci- major factor. I don't think it to get into small business and they're doing with their large ation and Celestial Naviga- matters much what it costs, be successful. "I see the com- systems isn't really out of tion—Jim believes the fault is let's get one that'll do the puter as a way of keeping them reach of the micros." There's with the printed program. "I can job—make it reliable and easy from failing," he says, but that ubiquitous software prob- show you what is wrong with to operate—and see if busi- present systems would only lem, though: so far, workable the programs," he says. "The nesses can afford it." "heighten the frustration software that will run reliably formulas are wrong. I don't The business market is level." on a micro has eluded Smoky know where they got those for- where Sexton envisions the Mountain Aero. mulas, but any basic finance future of the micro industry. His Where it Came From; What is the seemingly elu- book can show you the error." business activities over the Where It's Going sive job Jim so desperately years have been varied: grocery What initially sold Jim on wants his micro system to do? Plus Ultra the Hobby Level? stores, filling stations and microcomputers was a lot of It already is doing a great deal. Jim describes his experience other small operations that ran potential at a reasonable price. In addition to typing original with micros so far as "discour- concurrently with other oc- He had checked out large com- advertising letters and han- aging," but he hasn't given up cupations. He'd buy a business puter systems from IBM, Bur- dling maintenance, tie-down on the idea of further utilizing that was in trouble, straighten roughs and others, and the low- and insurance records, the his system to make his busi- it out, then sell it for a profit. est-priced package he could Smoky Mountain Aero com- ness more efficient. He This kind of transformation, he get cost about $58,000. The puter keeps track of flight-train- believes, however, there will says, is relatively easy because basic hardware for that system ing records for Veterans have to be some changes in the same problem usually ex- was only $12K, but enough soft- Administration-supported stu- hardware and software before ists: a lack of knowledge of ware and mass storage to do dents. The VA requires a com- personal computing will be what it is costing to do busi- the job for Smoky Mountain plicated series of records on each student to be filed each is investing even more heavily print out profits at the end of ADM-3 video terminal to his month. At Smoky Mountain in a time-share system. The each day. Currently, he gets DEC Writer, he'd turn off the there are at least 50 VA-certi- micro will continue to handle this kind of information only computer, pull out the I/O board fied students. "The computer the duties it already performs every two weeks from the with the first port configured reduces what used to take well: duties that wouldn't mess bank's computer. Smoky Moun- for the ADM-3 and plug in one three days each month to a cou- up the company's entire book- tain Aero also has a program to set up for the printer. After a ple of hours," Jim says. "Mine keeping system should some- do this on the micro, "but," Jim year of that—even with has paid for itself in that alone thing go awry. They'll purchase reiterates, "I'm afraid to use it repeated calls to Mits for if I could do nothing else with several video terminals to ac- because of the unreliability of help—he wrote a program to it." Still, Jim would like to see cess the bank's computer the computer." overcome an apparent hard- his system do more. directly, perhaps using the Jim Sexton has rejected the ware problem. He'd like to eliminate use of micro system for some internal idea of buying or leasing a big "They kept telling me to read the bank's computer entirely processing; that data could be machine. The cost is too high, the instructions. Well, the in- and switch to in-house process- fed to the large computer in a and he already has committed structions say if you're running ing for a sophisticated ac- block. around $8000 to micros. the thing one way to put a cer- counts-receivable and costing "What I really want to do is Besides, he still believes a tain switch up, but to change program for Smoky Mountain get a daily profit/loss state- microcomputer is capable of that for other conditions," Jim Aero. ment, which in this business is the job he wants done at a says. "They say, 'Where is the "We have an accounts-re- very, very difficult," Jim says. reasonable price. "I'm willing BASIC addressed?' and I have ceivable program written for "In this industry, we are both- to pay a bunch of money to no idea. I say, 'How the hell do use on our computer, but I'm ered by so many taxes and reg- develop a computer system you tell?'" afraid to start using it. If we get ulations that to employ some- that'll work," he admits. With the kind of software Jim into any of these screw- one at minimum wage to work And he'd like to see better wants to run, an important ups—dropping bits and such- the front counter and make documentation with the equip- capability is to read informa- it could really ruin our account- decisions on what Is taxable ment already available. One of tion off a disk or tape, update ing program, so we're still go- and what is not is difficult." the problems he had in the the information and put it back ing with the bank because I He'd like to use a terminal at beginning was with his Altair in the same place without trust the bank." the front desk tied to a comput- 2SI/0 boards. He couldn't make destroying what is on either er programmed to make those either of his two boards switch So, for now, instead of side. Documentation with his decisions, keep track of state, to the second port; so when he switching to an all-micro disk system is so unclear that federal and local taxes and wanted to change from his system, Smoky Mountain Aero so far he has been unable to make it work that way. "They use terms I simply don't understand. If they'd charge me, say, $1800 for the disk system, then another thousand for a six-page booklet of operating instructions I could understand, then I'd be willing to pay the extra thou- sand bucks." Micros Should Get Down to Business Well, I said in the beginning this story would be frustrating, discouraging, confusing. It is doubly so because I've talked with potential micro users and owners who say the same thing: they simply can't under- stand the instruction manuals. The manuals are either poorly written and illustrated, or writ- ten in such technical terms that only a designer or programmer with considerable experience could understand them. "It seems the micro industry is just not conducive to business applications," Jim Jim Sexton has spent hundreds of hours trying to develop hardware and software for his business. observes. "You really have to His experience with micros, however, has been discouraging. "I'd be better off with a mini. That's what I'd recommend to anybody interested in their own business computer," he says. Even so, the want to fool around with a com- investment has been a good one. The computer has paid for itself: "I'm not disappointed in my in- puter, spend hours to make it vestment, it has been worth It. It just falls way short of what I'd like it to do." work; I don't think businesses are willing to accept that. ware needs of that company, A few businesses—Smoky and if somebody else can fit it, Mountain Aero for one—have fine. If they can't. It's just too accepted it, but only because bad. I'd hate to see the micro in- the owners have an interest in dustry get to that point." computers. Most businesses Jim Sexton's working on the are interested only in what the problem. He has hired a full- computer can do for them, not time programmer in an effort to how many bytes it stores, what put his $8K worth of hardware chip it uses or how big the to full use. Right now they're power supply is. working on a parts-inventory The American public is in- program and trying to polish creasingly aware of computers' other aircraft-industry pro- power, and businesses are ex- grams so they will run reliably pecting more and more from on a variety of microcomputers. these machines they've heard Already Jim has what he calls a so much about. The heavy- "pretty good software collec- weights in the computer in- tion" he hopes will benefit Selling and servicing equipment such as this $475,000 Cessna 421 dustry aren't serving the small other Fixed Base Operators is only one facet of the Smol MICROPROCESSORS MICROPROCESSOR 1 FROM CHIPS TO SYSTEMS INTERFACING rf Rodnay Zaks MICROPROCESSOR 420pp, 150 illustr, ref C201 $9.95 TECHNIQUES INTERFACING Austin Lesea, Rodnay Zaks TECHNIQUES Our Bestseller. This book is the result of the 350pp, 320 illustr, ref C207 $9.95 author's experience in teaching microprocessors to more than 2000 persons. 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Allow 3 weeks Springfield Computer Workshop of Northern Virginia, Inc- for personal checks to clear. N.Y. State residents add approp. sales tax. (703) 321-9047 Availability, prices and specs may change without notice. WASHINGTON Bellevue Byte Shop (206) 746-0651 Operating Hours: Bellevue The Microcomputer Center COfuPVlGf M-W105E-S.T- (206) 456-3710 i : TM TH-Fm9E S-T WISCONSIN Janesville Austin Computers c osed sat & sun (608) 752-6002 GflCGrpfUCr P.O. Box 71 Fayetteville, N.Y. 13066 ' realistic controls corporation Phone (315) 637-6208 Today! Robert Baker 15 Windsor Drive A tea N J 08004 Writing Diagnostic Routines while your machine is running ver since personal com- maintenance. The programs the device-dependent tests are and the various control logic, Eputer systems first are written to detect minor passed, the system exerciser trying different bit patterns caught on, the area of diag- faults before they degrade can be run again to verify to check for shorted lines. nostic software has been over- system operation, and to help that that was the only system For convenience, you may looked. Few companies isolate and debug major fault. want to create some of these producing kits and hobby problems when they occur. A bottom up approach programs in ROM and have systems offer diagnostic pro- requires the least amount of them permanently available. grams to test and debug their Diagnostic Methods working hardware to be use- Loading programs would products should a problem be One of two approaches is ful, but a top down approach require a major portion of the suspected. Possibly such pro- generally taken for writing takes less time to isolate a CPU to be in working order, grams haven't been offered and using diagnostic pro- given system fault; so there so using ROM would elimi- yet because of the degree of grams. A bottom up approach are trade-offs. For either nate that problem. customizing each user per- starts by testing the smallest approach, the actual pro- A quick memory check forms while assembling his or entity in the system then grams could be similar, de- can verify that RAM memory her system. Because of using that proven-good device pending on the system and is working correctly by writ- competition in the market, to test the next device in the the application. ing all zeros and all ones to most systems are a conglom- system until all devices have each location, reading it back, eration of bits and pieces been tested. Individual com- Writing A Test Program and comparing the data. You interconnected for a partic- ponents are then tested in Why not write a collection may want to check another ular application. Thus, most clusters or subsystems, and of test programs while you memory pattern such as al- hobbyists are forced to write finally the entire system is have a working system to try ternating ones and zeros their own diagnostic or tested, or exercised, as a them on? Debug your pro- (10101010) as well as check- maintenance programs (usual- whole. grams thoroughly when writ- ing memory addressing logic ly after a major problem A top down approach, on ing them so you're sure that by insuring a test pattern had develops) without really the other hand, starts by any problems detected are not been written into another knowing what they're doing. running a system exerciser to caused by hardware and not location. It's very difficult to debug test all devices at once and software. Try a bottom up software if the hardware is isolate a problem to a given approach first as this should After the CPU and mem- not working properly! subsystem. More detailed, make the programs easier to ory have been tested, you can On mini and larger size device-dependent programs write. Start out with a few then proceed to test any computers, the manufacturer are then run for the particular simple programs to check the other devices you may have usually provides various faulty device or subsystem to CPU machine instructions, in your particular system. diagnostic programs to be run further isolate and help debug checking operands, condition Test each device separately at regular intervals by the the problem. Once the prob- codes, etc. Then check data and thoroughly before going user as a form of preventive lem has been corrected and paths to and from the CPU to the next. For starters, try a program to test your CRT accomplish and how you display or video terminal want to control your test with: programs. • a character generator check, the Computer Store full lines of each character...... , , . , Make It Useful • display memory test (swirl the store for the professional pattern). The first line is a whatever devices are full character set. Each line '^sic after the first starts with the features should be included next letter in the character convenience set after that used on the line increased usefulness of Offers above it. Therefore, each programs. Each test character will be on a diag- ^ program should give onal, and will appear in each ^ '^'eai'ly defined indication A Unique storage location as the test is ^n error is detected, run, and the display scrolls. ^ message For example: ^ terminal or simply a machine stop at a specific address. If error stops are Profit abcdefg used, separate halts or stops bcdefg should be used for each Opportunity cdefg possible error so the address defg at which the machine stops will indicate what error was FOR detected. For added con- Other patterns can be added venience you may even want to test special features, etc., to generate an error die- depending on the particular tioriary to list and describe Software display. To test a keyboard ®3ch possible error halt and you can try a program that: 9ive some possible causes or cures. Also, keep a log of the Companies • displays on your terminal errors and causes detected by or CRT the code for the key your programs for later refer- depressed and the actual char- ence. They may save you acter. from debugging the same Systems Houses • asks you to type each char- problem again several months acter in a set sequence and or years later. checks the code received. Another desirable feature should be the capability to Another useful test could loop on any test for scoping Computer print continuous lines of any purposes, possibly with a character typed in by the sync pulse generated at the user. When another is typed start of each pass. Other Retailers in, the printer would change features can be added as to that character. Similar desired, depending on your The computer Store's Dealer Affiliate tests can be written to check particular system and how Program features the Data General the particular features or you want to test it. Try to microNOVA computer line and estab- functions of other displays keep it simple but flexible, lished professional business applica- and terminals. Use easy-to- and easy to use. tions software for resale to the explo- recognize patterns on printers Plan ahead and prepare sive small business computer market. or terminals and keep the yourself for the inevitable, Sales and technical training included. tests simple! Sooner or later you're bound For details: If you have tape drives, to have a hardware problem, cassettes, floppy drives, opti- and your local TV repairman Call Paul Conover cal readers or joysticks, don't will probably not be able to 617-272-8770 forget to test them also. Test help you, let alone know every device in your system what you're talking about, thoroughly, one at a time. An even better idea: Run the Later you can add a simple tests periodically and catch exerciser to get everything small problems before they fbe Computer Store working at once and check become major ones. Your 120 Cambridge St. for device interactions. My time spent writing diagnostic Burlington MA 01803 617-272-8770 advice is to save this for later programs for your system C34 when you start to get a feel now will be repaid many for what you really want to times in the future. • illustration, the typical routine which converts incoming serial data to parallel form does so by testing the middle of each bit in order to determine whether it represents a binary Experiments in Software 1 or 0. Following examina- tion of the center of one bit, the program will loop through a time delay routine for a fixed length of time. This length of time corre- sponds to the duration of one bit. Upon exiting from the serial to parallel conversion loop, the program tests the next bit, loops . . . and so on. The requisite loops are dependent on the speed with which the CPU executes its instructions (i.e., does it have a 1 MHz clock, 2 MHz clock, Dan StogdiH finite length of time, one bit hardware devices (the UART etc?) and by the access time 182 Victoria Street on each of the parallel wires and the ACIA) designed to of the memory. With slower St. Marys Ontario of the data bus. Nevertheless, achieve this end. Instead of memories it is general Canada NOM 2 VO in order to communicate with hardware, however, software practice to insert one or more the outside world, this may also be employed to wait states before the mem- S most hobbyists are parallel data must frequently attain the same results. ory is read. As a consequence, Aaware, microcom- be converted to serial form in Although there have been to some extent serial-to- puters generally employ which each bit of a given data several articles on this subject parallel conversion routines parallel data to carry out word Is transferred sequen- in the literature, most of tend to be machine or system their internal transactions. tially between the micro- them contain a cautionary specific. That is, the CPU expects all computer and its external note related to the param- In this article, I intend to bits of a given data word to devices. Technology has eters associated with the soft- describe a simple serial-to- exist simultaneously for a provided us with at least two ware timing loops. By way of parallel routine, READ, and a Symbolic Address Location Machine Code Mnemonic Comments CALIBRATE 000-200 041 LXI H Initialize the storage 201 100 location for the 202 000 critical value TST 203 333 IN Input the parallel 204 005 port 205 346 ANI Set up a 206 001 mask 207 302 JNZ If no start bit 210 203 TST go back to TST 211 000 212 001 LXI B Initialize the B-C 213 000 register pair to 214 000 zero 215 315 CALL Call subroutine 216 261 TIMER 1 217 000 220 161 MOV M,C Store C register 221 043 INX H Bump the pointer 222 160 MOV M,B Store B register 223 166 HLT Halt ... Unused memory space TIMER 1 000-261 003 INX B Increment B-C pair 262 333 IN Input the parallel 263 005 port 264 346 ANI Set up a 265 001 mask 266 177 MOV A,A Extra-parallels TIMER 2 267 267 ORA A Extra-parallels TIMER 2 270 312 JZ If no data bit 271 261 go back to TIMER 1 272 000 273 311 RET Return to CALIBRATE Table 1. This routine determines the critical value and stores it in addresses 100 and 101 (octal) on page 0. parallel-to-serial routine, connections made to the =". 2. WRITE, which allows my 3P-I-S in order to boost the OF iC2 Altair 8800 (through one of TTL signals at the parallel I/O the parallel ports on a port to RS232C level 25 = N CONSECTOH Processor Technology 3P-I-S capable of interfacing with CN BiC-^ interface) to converse with my terminal. As can be seen, my CRT terminal which for outputting data, one K employs an RS232C serial output line of a parallel I/O I/O. Of greater importance, I port (available at J1 pin A) is {K> will outline a simple tech- fed back to the input of an -FT 2i nique by which anyone can unused gate of IC 5, the 1488 determine the values of the which normally boosts the loop counters for any partic- 3P-i-S's UART output to ular system. RS232C level. For inputting data, one input line of a Some Preliminaries parallel port (available at J2 Fig. 1. The simple modifications to the Processor Technology 3P+S Fig. 1 illustrates the simple pin Z) is connected to the interface. Symbolic Address Location Machine Code Mnemonic Comments READ 000-000 305 PUSH B Save these 001 325 PUSH D registers 002 345 PUSH H 003 021 LXI D Set up number 004 010 of word bits in reg. E 005 000 Clear reg. D TESTE 006 333 IN Input the 007 005 parallel port 010 346 ANI Set up a Oil 001 mask 012 302 JNZ It no start bit 013 006 go back to TESTR 014 000 015 001 LXI B Initialize B-C pair VALU 1 016 224 with loop counter 017 002 value 020 315 CALL CaU TIMER 2 and 021 061 loop for awhile 022 000 NEXT 023 333 IN Input the parallel 024 005 and fetch a data bit 025 346 ANI Set up 026 001 mask 027 202 ADD D Add D reg. to A reg. 030 017 RRC Shift reg. A to right 031 127 MOV D,A Save byte in reg. D 032 001 LXI B Initialize B-C pair VALU 2 033 270 with loop counter 034 001 value 035 315 CALL Call TIMER 2 036 061 and loop 037 000 for awhile 040 035 DCR E Decrement bit counter 041 302 JNZ Fetched all bits? 042 023 No. Go back to next and get 043 000 another bit 044 172 MOV A,D Put word in Acc. 045 247 ANA A Set the flags 046 342 JPO If parity is odd 047 057 jump to WRONG 050 000 051 346 ANI Strip the parity 052 177 bit 053 341 POP H Retrieve the 054 321 POP D previously stored 055 301 POP B stored registers 056 311 RET Return to calling program WRONG 057 166 HLT Safety halt 060 000 NOP Unused TIMER 2 000-061 013 DCX B Decrement loop counter 062 333 IN Extra-parallels TIMER 1 063 005 Extra-parallels TIMER 1 064 346 ANI Extra-parallels TIMER 1 065 001 Extra-parallels TIMER 1 066 171 MOV A,C Fetch counter value 067 260 ORA B Are B and C zero? 070 302 JNZ No. keep looping 071 061 072 000 073 311 RET Return to calling program Table 2. This program converts incoming serial data to parallel format and checks for even parity. (Note that on my system 1 obtained a critical value of 270-001, as shown by VALU 2.) Resting Level Logic 1 * 2 stop parity bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 start bits bit bit Logic 0 _9.09 ms 100 ms Fig. 2. The bit composition of the ASCII encoded character A (capital), and its associated timing values when transmitted at a rate of 110 baud. Note that the resting level is always logic 1, while the start bit is always logic 0. output of an unused gate of based on the hardware acter A (capital), and its critical value. IC 10, the 1489 which UART. Simply borrow that timing values when it is trans- Table 1 contains a short converts the incoming part of the circuit which is mitted serially at a rate of program labeled CALI- RS232C signal to TTL level responsible for changing the 110 baud. Note that each bit BRATE. This program compatible with the UART's UART's I/O signals to the occupies a time of 9.09 ms operates by testing for the input. appropriate drive level con- and that the resting level is start of transmission of the Owners of other parallel sistent with your particular always logic 1, while the start character A (for example) I/O boards and/or current peripheral. bit is logic 0. In addition, when it is transmitted by the observe that the first data bit loop type terminals can also terminal. Upon detecting the of the A is always a logic 1 interface them readily. Back The Critical Value logic 0 start bit (see Fig. 1), it . . . this is very important in calls up a subroutine TIMER issues of 73 and Kilobaud Fig. 2 depicts the bit com- determining what I call the 1, which alternately incre- contain a number of circuits position of the ASCII char- Symbolic Address Location Machine Code Mnemonic Comments WRITE 000-100 305 PUSH B Save these 101 325 PUSH D registers 102 345 PUSH H 103 247 ANA A Set the flags 104 352 JPE If even parity 105 111 in Acc. then 106 000 skip to EVEN 107 356 XRI Make Acc. 110 200 even parity EVEN 111 127 MOV D,A Save the word in reg. D 112 036 MVI E Set up number of 113 010 word bits in reg. E 114 257 XRA A Zero the Acc. 115 323 OUT Out this as a start 116 005 bit to the terminal 117 001 LXI B Initialize the VALU 2 120 270 loop counter 121 001 122 315 CALL Call TIMER 2 123 061 and loop 124 000 OUTIT 125 172 MOV A.D Move the word to Acc. 126 323 OUT Output a character 127 005 to the terminal 130 017 RRC Shift reg. A to right 131 127 MOV D,A Save the word in reg. D 132 001 LXI B Initialize the 133 270 loop counter 134 001 135 315 CALL Call TIMER 2 136 061 and loop 137 000 140 035 DCR E Decrement bit counter 141 302 JNZ Outed aU bits? 142 125 No. Go back to outit and 143 000 keep outputting bits 144 076 MVI A Put a 1 in Acc. 145 001 Use as a stop bit 146 323 OUT Output the stop bits 147 005 to the terminal 150 001 LXI B Initialize the VALU 3 151 160 loop counter 152 003 for two stop bit lengths 153 315 CALL Call TIMER 2 154 061 and loop 155 000 156 341 POP H Retrieve the previously 157 321 POP D pushed registers 160 301 POP B 161 170 MOV A,B Restore the Acc. 162 311 RET Return to the main program Table 3. This program converts parallel data to serial format and outputs it to the terminal. merits the value in the B-C until all bits have been tested register pair and tests for the and the word assembled in beginning of the first data bit, parallel. a logic 1 (see Fig. 1). Upon the Computer Store detecting the logic 1 start bit, The WRITE Program TIMER 1 is exited with a Table 3 contains the pro- the store for the professional relative value of the bit length gram WRITE, which converts in the B-C register pair. a parallel data word to serial Should you run the program format and outputs it to the several times, you will see terminal. It also assumes that that the critical value stored in the I/O port is located at addresses 100 and 101 (octal) address 005 and that serial will remain quite stable. transmission to the terminal (Note that address 100 con- is occurring through line zero tains the least significant bits of the parallel outport (DOO). and that address 101 contains VALU 3 produces the stop the most significant.) If you bits and is equal to the have access to a terminal with critical value converted to adjustable baud rates, you decimal, multiplied by 2, and will notice that the critical converted back to octal. $595 value becomes progressively smaller as the baud rate Conclusions NEW increases. Both routines assume that they will be called up by The READ Program other programs to provide CENTRONICS Table 2 contains the pro- I/O services; as such, the gram READ which converts states of all registers except A MICROPRINTER incoming serial data to and PSW are saved on the • Low Cost parallel format. It assumes stack so as to not interfere that the parallel I/O is at with other operations. As • Small Size address 005 and, further- provided, both routines • Quiet more, that the serial data is return to the main calling entering through line zero of program with the data word • 180 Lines/Minute the input port (DIO). VALU in the accumulator. In addi- • 5 X 8 Dot Matrix 2 is the previously obtained tion, WRITE assumes that the critical value. VALU 1 repre- data word is in registers A • Elongated Characters sents the critical value con- and B on being called. Lastly • Parallel Interface (P1) verted to decimal, multiplied the routines provide for by 1.5, and converted back to parity generation and check- octal. ing (even parity, in the AVAILABLE: OFF-THE-SHELF TIMER 2 may appear to present case). PERFECT FOR THE APPLE II COMPUTER contain some irrelevant While described from a instructions. Not really. viewpoint of being used with TIMER 1 and TIMER 2 were a terminal, the routines fashioned in such a manner should lend themselves for Also Featuring: that the critical value use as cassette I/O routines in • Data General microNOVA line obtained with TIMER 1 concert with appropriate would be directly applicable encoding/decoding schemes. •CROMEMCO with TIMER 2; their respec- The software connoisseurs • APPLE tive instructions were juggled among us could make them around while insuring timing more efficient memory-wise. • WANG compatibility between the In addition, I am sure that • COMPUCOLOR two routines. CALIBRATE and READ/ The READ program tests WRITE could be combined in for the beginning of the start such a way as to make the OFF-THE-SHELF DELIVERY bit and then circulates whole process automatic in FRANCHISE OPPORTUNITIES AVAILABLE through the loop for a time nature. The Computer Store has a unique franchise oppor- equal to 1.5 bit times What initially started out tunity. Contact the Burlington Store. (governed by VALU 1). At as an experimental project is this point, the middle of the now in everyday use on my first data bit is tested. Sub- system. By all means experi- sequently, TIMER 2 loops for ment with them and have the Computer Store 1 bit length (governed by 120 Cambridge St. 63 S. Main St. fun. As ever, if you have any Burlington MA 01803 Windsor Loclcs CT 06096 VALU 2, the critical value), questions drop me a line and 617-272-8770 203-627-0188 exiting near the center (hope- I will try to help out. Keep fully) of each successive bit on computing. • Peter Stark binary is easy and fast. (Use Box 209 of these number systems Mt. Kisco NY 10549 constitutes external oper- ations.) Whether octal or hex is used depends partially on the length of the binary numbers used, and partially on per- sonal preference. Computers Computer Math Primer handle binary numbers of a fixed length, called a word length. Most hobby com- puters use a word length of 8, beginner's introduction meaning they handle binary to number systems numbers in groups of eight digits. If the binary word length is divisible by three, octal is generally used; if it is divisible by four, hex is employed. If it is divisible by both three and four, or by nce you understand a 16. Table 1 shows their rela- 101 is the fifth number after neither, then it's a matter of Olittle about hex, that tionship. 0, it stands for 5. choice. will make computers a little Notice that binary num- There are no 8s or 9s in So, most hobby computers less magical and bring them bers only use 0 or 1; there are octal numbers, so after 7 with a word length of 8 use down to earth. So here goes. no digits larger than 1. So, comes 10; after 17, 20; after hex (externally), although Hex is short for hexa- the next number after 0 and 77, 100. there are exceptions: the decimal, one of four number 1 is 10 (0010), since we have Decimal numbers go from 8008 CPU uses octal, as does systems used with computers. to skip over 2, 3 and so on. 0 through 9. That's only ten Heathkit's new H8. The The other three are binary, (For most purposes, 10 and different digits, so after 9 we 12-binary-digit (12-bit - a bit octal and decimal. Each is 0010 are the same; the be- have to start doubling up; is a binary digit) Intersil uses based on a particular number: ginning zeros don't change after 9 comes 10, and so on. octal. binary uses the base 2, octal things.) After 10, binary The hexadecimal number Most hex or octal numbers the base 8, decimal the base numbers skip to 11, then skip system has 16 different digits. used with small computers 10 and hexadecimal the base to 100 and 101, etc. Since The first ten are the same as are small two-digit hex or the ten digits of the decimal three-digit octal numbers. system — plus there are six Let's use those as examples of more. how to do magic with them. I think whoever devised (Assume only positive inte- hex made a big mistake here. gers for a starter.) Having six new digits, he should have invented six new Converting Hex to Binary symbols for them. Instead, he For each hex digit, replace simply gave his six new digits it by its four-bit binary old symbols: A, B, C, D, E equivalent from the table. and F. Consequently, we have For example, to convert hex a number system that goes A3, replace A by 1010 and 3 from 0 to F. (After F, by the by 0011 for a binary result of way, you have to start 10100011. doubling up as in decimal. After F comes 10, which Octal to Binary corresponds to 16 in dec- For each octal digit, re- imal.) place it by the rightmost Computers use binary three bits of the corre- numbers for their internal sponding binary number in operations. Octal and hex the table. To convert octal numbers are used by the 243, for example, replace the people who use computers 2 by 010, the 4 by 100 and (not computers themselves) the 3 by Oil. The complete because they are easier to see binary number is 010100011. and interpret (A3, for ex- Now, for a second trick: This ample, is easier to read than procedure gives you a total of 10100011). Computer people nine bits, whereas most small use octal or hex numbers computers need only eight. rather than decimal because Fortunately, the leftmost bit their conversion to and from will usually be a zero, and so Binary Octal Decimal Hex 32+16+4) and you'll see that because you will just get an 0000 0 0 0 binary 10110100 converts to answer of 22.5, and then you 0001 1 1 1 180 in decimal. won't know what to do. Use 0010 2 2 2 pencil and paper. 0011 3 3 3 Octal to Decimal Eight goes into 180 0100 4 4 4 0101 5 5 5 This conversion is the twenty-two times, with a 0110 6 6 6 same as binary-to-decimal remainder of 4. (After a while 0111 7 7 7 except that the values of each you'll figure out how to use 1000 10 8 8 digit are 1, 8, 64, 512 and so your calculator for this, too.) 1001 11 9 9 on — each value is eight times Put away the 4, and divide 1010 12 10 A 1011 13 11 B more than the one before it. the quotient by 8. 1100 14 12 C To convert octal 264, for Eight goes into 22 twice, 1101 15 13 D example, use the preceding with a remainder of 6. Save 1110 16 14 E technique with the new the 6, and divide 2 by 8. 1111 17 15 F values. Eight goes into 2 zero Table 1. times, with a remainder of 2. 2 6 4 Since we are down to a x64 quotient of 0, we can stop can be crossed out, giving the Binary to Decimal 128 48 4 dividing by 8. final eight-bit answer of The easiest way to do this Now add up 128+48+4=180. Now take the three re- 10100011. is to convert the binary mainders (4, 6 and 2) and number to octal or hex first Hex to Decimal write them backwards: 264. Binary to Hex and go to decimal from there. Same as before, except the This is your octal number. Starting from the right, If you insist on doing it di- digit values are now 1, 16, separate the binary digits into rectly, then here's how. 256, 4096, etc. (remember to Decimal to Hex groups of four; replace each In a binary number, each start with 1 at the right) — This conversion is the group by its hex equivalent. bit has a specific value; to each value increases 16 times. same as decimal-to-octal, Binary 01100100 would be convert, you have to multiply Hex 2C4 converts like this: except you divide by 16. For split into 0110 and 0100. each bit by its value and add 2 C(12) 4 example, to convert 180 to 0110 is replaced by 6 and the results. Starting from the x256 X 16 ^ hex, start by dividing 180 by 0100 by 4, giving hex 64. right, the values are 1, 2, 4, 8, 16. This conversion is easy if 16 and so on — each value is 512 192 4 Sixteen goes into 180 the number of bits is any twice the preceding value. 512+192+4=708. eleven times, with a re- multiple of 4. If not, you To convert the binary mainder of 4. Save the 4 and must add zeros at the left 1011, transcribe the number Decimal to Binary repeat. until it is. For instance, to (spread it out), and under Convert to octal or hex Sixteen goes into 11 zero convert 11011 you first add each bit write its value. first; then convert the result times, with a remainder of three zeros to make it to binary. There is a direct 11. Again, we stop dividing 1 0 00011011, then split it up way, but it's likely to take when we get a quotient of 0. 8 4 into 0001 and 1011, and longer, and you will probably Write the remainders down finally convert to 1 B. Remember to start with a make a mistake — so don't backwards, but convert any value of 1 at the right. Now bother. remainder above 9 to its hex Binary to Octal multiply each bit by its value, digit. In this case, the 11 This is the same as the hex like this: Decimal to Octal converts to B, and the hex conversion except that we use 1 0 1 1 This conversion is done by answer is B4. groups of three bits. For x8 x4 x2 Xl dividing the decimal number example, 01100100 is an by 8 and saving the remain- Complements eight-bit number, and eight 8 0 2 1 ders. Keep doing this until A complement is an bits cannot be separated into Finally, add 8+0+2+1 = 11. you get 0, and then put the opposite; in the case of com- groups of three; so we add an (Check the table and you'll remainders together back- puters, complements are used extra zero to make it see that 1011 in binary is 11 wards. for negative numbers. There 001100100. We can then in decimal.) This sounds crazy until are two kinds of comple- break it up into 001-100-100. To see how this works for you see how it's done. Let's ments: one's complements We can convert each group larger numbers, see Example say you want to convert 180 and two's complements. The into octal using the table if 1. (With a little practice, you from decimal to octal. Start one's complement is easy to we note that 001 is the same can skip multiplying by zero.) by dividing 180 by 8. Don't find, but the two's comple- as 0001, or an octal 1; 100 is Add the results (128+ use your calculator for this ment is generally used. the same as 0100 or an octal 4. Thus, binary 001100100 is octal 144. (Just a reminder: We are 1 0 1 1 0 1 0 0 working only with positive x128 x64 x32 x16 x8 whole numbers (integers) 128 32 16 4 now. Negative numbers or fractions are a different ball Example 1. game.)