Understandable for beginnerkilobaus ... interesting for expertsd
June 1978 / Issue #18 / $2.00 / DM 7,50 / Sfr 8,10 / Ffr 16,0 / UK £2
Emerson Brooks 22 Taming the I/O Selectric ... Part 1: hardware interface
Norman E. Thagard, M.D. 26 Home-Brew Z-80 System ... Part 1: front-panel construction
AI Gerbens 32 A Strategy for Healthy Living ... computerized exercise/fitness program
John Craig 36 A Tour of the Faire ... Part 1: some of the people and products
Charles R. Carpenter 42 Tiny BASIC Shortcuts ... overcoming some limitations
Howard L. Nurse 46 Baudot... er... Murray, Meet the H8
Michael Slater 52 8080, Z-80 or 8085 ... Intel's latest deserves a closer look
Edward Copes 57 One Keyboard: Hex and ASCII... simple converter circuit
Jjj Dan Dederick 60 Is the Malibu Model 160 the Printer for Your Business System?
Clint H. Woeltjen 64 The Great Computer Conspiracy ... a humorous look into the future
Paul J. Terrell 67 Personal Computer Shows ... some thoughts on the future
Mac Oglesby 68 Cross-Country Balloon Trip ... you and your SR-52
William Nichparenko 72 Transfer Vectors vs Absolute Addressing ... a better approach
Jeffrey G. Towle 76 Error Correcting Codes ... not as difficult as you think
John A. Lehman, Ray Graham 80 ASCII to Baudot... er... Murray (the Hard Way)
Joe Roehrig 84 Bowling Scores for Dollars ... big bucks are waiting!
Dr. Jack W. Crenshaw 90 It's Here: Machine Language for the TRS-80 ... Radio Shack's T-BUG
Dr. Mark Boyd 92 Two Systems Sharing the Same Bus ... a look at distributed computing Dr. Lance Leventhal 100 Computers in Classrooms: Teaching the Teachers
Publisher's Remarks—4, Editor's Remarks—7, Around the Industry—8, Books—11, New Products—14, Letters—18, Kilobaud Classified—112, Calendar—112, Corrections—112, Contest! —117 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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KIWI is a registered trademark of Commodore International Ltd. and the Commodore companies to describe microprocessor boards and systems square feet. When a density of Software Needed one person per ten square feet is reached, an exhibit hall is generally considered full, and it is I don't think there was one difficult for people to move manufacturer or dealer who RIKLIvSHEKV S around. This leaves room for didn't express the universal cry elbows and a bag of literature, for programs. Hobbyists have but not much more. At times the been spending a lot of money on REMARKS show reached this density in the hardware, but so far there has more popular spots, indicating a been very little they could do with Wayne Green possible head count of 1100 in the their expensive systems except aisles. play Star Trek, Submarine, advertising, so it would have to Mastermind and so forth. The French Do It Again That may seem a bit scant in pull a lot of customers to be view of the interesting numbers The Kilobaud plan for dis- worth the expense. Bob said that announced by the Chairwhat- tributing software was enthu- A letter from W3NET included they had renewed their contract ever, but I like to check little nit- siastically embraced by every- a reference from a navy- for the space, if that told me picking items like this, so every so one . . . now all we have to do is published book, and it covers the anything. It sure did. often I would take a quick run get it going. We do have the staff history of Teletype codes. The When we were pricing displays down a few aisles, counting the and the equipment to get this upshot of all this is that the five- for promoting Computermania, feet and dividing by two. There project running, so I hope the level code we've been using all we checked on the cost of the bill- were seven aisles in all, with four first programs will be coming out these years is not Baudot at all boards at the airport . . . hoot of them shortened by the cut-off in the next few months. Programs ... it is the Murray code, mon! They cost a couple hundred corners of the hall. This shorten- for the TRS-80 and PET will be developed by Donald Murray dollars a month each . . . just for ing just about made up for the out on cassettes. We have a first- around 1901. The Baudot code is the billboards ... so I'm afraid space in the three cross aisles. My rate lab for checking out pro- entirely different . . . though still to even speculate what a kiosk counts confirmed the approx- grams, a superb cassette duplica- a five-unit code. For instance, in like that runs. imately 1000 attendance figure tion system for bulk production case you don't want to believe It's located where every pas- during the more crowded times. of cassettes, the publishing facili- me, the letter R in Murray is 2 <£ senger has to go right past it, so ties for printing documentation, 4. In Baudot, R is 3. In Murray the visibility is high. There are When the crowd density gets to the sales force and list of dealers code, the uppercase R is the some brochures available to help five square feet per person, there to distribute and an international number 4. In Baudot, uppercase people remember the name and is no longer room for elbows or rep organization to get us into R is a hyphen. Convinced? address of the store . . . and a much arm movement, and shuf- every country. Murray code is also known as the rough outline of what they are fling around is quite difficult; and this could account for a total Programmers can do a lot International Telegraph Alpha- selling. This is tremendous pro- worse than get in touch with bet No. 2. motion for microcomputing. of up to 2200 people in the exhibit aisles. Kilobaud about publication and It's time to change to ASCII The airline magazines are run- distribution of their programs. With 150 exhibits to see and a and bury this whole mess. ning a special computer section in They must be complete and ready total of 1500 minutes of show June, so keep your eyes open if to go, with thorough documenta- time, maximum, no one could you are traveling to NCC or the tion. The deal is simple: 20 per- spend more than an average of Atlanta Hamfest/Computerfest. cent royalty on our receipts. This ten minutes per booth and see the Spadework is about five times the going rate, whole show. The attendance was and we hope that we can establish scant on both Friday and Sunday this as a norm for this field by There it was! Right by the ramp mornings, so very few people starting it out that way and main- leading to the United Airlines The Second Faire managed to get in the entire 1500 taining this percentage. plane at Logan (Boston) I saw minutes. The familiarity of the this kiosk with a PolyMorphic faces by Sunday indicated that a What kind of programs are microcomputer ... all set up The San Jose Computer Faire lot of people did come all three needed? Just about anything for and running. It was put there by was enjoyed by just about every- days and made an effort to see all the TRS-80 can be instantly the Computer Shop of Cam- one. It was packed with people of the exhibits. distributed. At present the pro- bridge and must have cost a bun- and there were many more pro- grams should fit the 4K systems, dle. I hope it draws some business spective exhibitors than space for Each person who got anywhere but it won't be long before we'll for them. exhibits. near the Kilobaud booth was be needing most programs to asked to fill out a questionnaire Just to be sure, I called Bob Many exhibitors mentioned work with the 16K systems. which would be entered in a Rivers at the Computer Shop and that there seemed to be a lot less Almost anything will go for the drawing for a Caribbean cruise. asked him how effective the kiosk room than there had been last PET too . . . 8K systems. Few passed up the opportunity. was. That's awfully expensive year at San Francisco . . . room In the long run we will be able for fewer exhibits . . . and tiny By Sunday we found that most of to do best for programmers who the passersby had already filled in II aisles which quickly filled up, work on what we call vertical making it very difficult to get a card, indicating a high percent- systems. These would be program around. age of show-goers coming back packages that would enable com- for a second and third day to see A check with a Convention puter stores to sell complete sys- the exhibits. Facilities Directory showed us tems to specific businesses. Let's that San Francisco had 37,000 Though it's possible that a few say a programmer has a good square feet in the main room and people managed to see the show friend who runs a moving-van 30,000 more in the two side and not get near the Kilobaud service. I picked that at random rooms, for a total of 67,000 booth, this is unlikely. Our count by opening the Yellow Pages. He square feet. The San Jose hall had on the filled-out cards, after sort- would then consult with his mov- only 30,000 square feet . . . plus ing out the duplicates (some peo- ing friend and develop a program about 2000 more for the micro- ple try to increase the odds on package that would do everything booths in a separate room. No these things), came to 4100. a moving-van firm could want wonder it seemed so crowded A check with several exhibitors . . . everything. ... it was half the size of the San who were handing out literature Once the package was done Francisco Civic Auditorium. indicated that some had handed and carefully checked with a cou- A rough calculation of the aisle out over 3000 pieces . . . others ple local van firms for accuracy space showed about 11,000 claimed close to 5000. and completeness, we would package it and sell it through ingly? Our system should make it anywhere. On line at present are computer stores. Stores would possible for programmers to get two Altairs, an Imsai, an Ohio take the package, set it up to rich beyond their wildest dreams. Scientific Challenger, a Heath work on a system and then call Suppose we come up with a hot H8, an Hll and five Compu- m*m van firms to come in and see it at moving-van package . . . and colors. Peripherals on line are a work. It is unlikely that many sell it for $995 to the customer. Centronics 51 printer, a G.E. would pass up the system. When This would wholesale to the Terminet, a Teletype, an OSI Publisher you consider that there are over dealer for $597 (40 percent off). disk, two Altair disks, a North Wayne Green 80,000 such firms around the The rep would get 10 percent, Star disk, the H10 and H9, the Executive Vice President country, you can see that sales leaving a net sale of $537.30. SWTP CT-64, a Computalker, a Sherry Smythe Editor could be vigorous. Twenty percent of that would clock module, the Heuristics John Craig come to $107.46. If only 10 per- board, an S.D. Sales Z-80 etc. Managing Editor There are hundreds of vertical John Barry packages that can be developed to cent of the van firms bought the Barry, our tech, is working to Editorial Assistants help computer stores with their system, this would net the pro- I/O all of this to our Prime mini- Dennis Brisson Susan Gross sales . . . and these should bring grammer $859,680 (before taxes). computer system as well as the Administrative Assistant in handsome royalties. I suspect that sales will be more TRS-80 and PET. This will Dotty Gibson Production Department Next we come to computer- like 75 percent of the industry enable us to check out submitted Lynn Panciera-Fraser aided instruction . . . and the than 10 percent, but why build programs on just about every- Craig Brown the pie factory in the sky? A 75 Gayle Cabana possibilities for thousands of thing popularly available . . . Robert Drew more programs. Every course percent sale would bring in about lacking only a 6800 system. Carl Jackson $6.5 million in royalties. Michael Murphy taught in school—and those that In addition to our wanting to Weston Parker should be taught in school—are Is $995 a little high for such a know personally how all the vari- Noel R. Self Robin M. Sloan good prospects for this field. package? The customer would be ous systems work, another reason Typesetting Home-oriented programs will buying about $15,000 or so in for all this hardware is to give us Barbara J. Latti the ability to produce programs Jennifer Johansson be popular . . . security pro- hardware to go along with it, so it Marie Walz grams, general business pro- would really be miniscule . . . for sale . . . and be sure they all Photography grams, games ... the list is, for- work on the systems we say they Bill Heydolph running less than $25 a month! Tedd Cluff tunately, endless. What about my plan for $7.95 will. Associate Editors Programs that are usable on Don Alexander software? Oh, we'll have a lot of Tim Barry more than one system will be that. The programs for games, Bob Buckman checked out on other systems in for homes, general programs, Sheila Clarke What's Coming? Rich Didday the Kilobaud labs ... we have teaching programs, these will be Phil Feldman most of the microcomputer sys- of interest to much wider interest Doug Hogg, PhD Initially we'll be putting out Tom Rugg tems set up for this . . . and even groups, and we can look for sales Peter Stark our maintenance man is into in the millions of these programs. programs on cassettes. After that Bookkeeper we'll probably be using more and Knud E. M. Keller working up programs. Of course Most of the TRS-80 and PET Director of Marketing we have the TRS-80 (16K), the programs will come in this cate- more disks, then perhaps ROMs; Daniel D. Savage PET, Altairs, Imsai, OS1, ISC, but what will be next? Merchandising Manager gory ... at least until the hard- Robert LaPointe Heath H8 and Hll, etc. This ware is available for business use With the prices on video re- Area Rep. Manager place is microcomputer heaven. of these systems. Cynthia Gray cording systems coming down, Circulation Programmers should send in Are you still reading and not we may soon see video recorders Rhonda Ramsey used for program and data Receptionist complete listings, documen- rushing to your computer to pro- Doni Anne Jarvis tation, some data on how to use gram? You need some All-Bran storage. These recorders are all Computer Data Control the programs and what they can set up to be easily controlled by a Judy Waterman . . . badly. Judy Brumaghim do . . . plus a cassette or disk computer. Linda Cate with the program on it, depend- Mary Kinzel Picture, if you will, a study Computer Technician ing on the system. We would like course of the future . . .on video- Barry Bressler to get as good a print of the pro- The Kilobaud Lab Computer Programming tape. It will have full television Ron Cooke gram as possible. action and sound in color Richard Dykema Programmers interested in Steven Lionel As soon as the TRS-80 and . . . and program your computer Printing tackling a major programming PET are brought into the system as it goes along. It will show Dan Morgan package would do well to register material and then stop and ask a Andy Corneau we'll have one of the most exten- Mailroom with us. This could prevent ten sive microcomputing systems question about what has been programmers from working up Theresa Toussaint very similar dental programs, for Bill Barry example. Tell us what you are Sue Chandler Reader Responsibility Ethan Perry planning to put together and we'll Advertising let you know if anyone else is Meidi Kulish One of your responsibilities, as a reader of Kilobaud, is to aid Marcia Stone working on something similar. Bill York Packages will be chosen on the and abet the increasing of circulation and advertising, both of European Distributor basis of excellence, not first which will bring you the same benefit: a larger and even better Monika Nedela Australian Distributor come. magazine. You can help by encouraging your friends to sub- Katherine Thirkell scribe to Kilobaud. Remember that subscriptions are guaran- UK Distributors L P Enterprises teed—money back if not delighted, so no one can lose. You can also help by tearing out one of the cards just inside the back Very Rich Programmers Kilobaud is published monthly by 1001001. Inc . cover and circling the replies you'd like to see: catalogs, spec Peterborough NM 03458 Subscription rates m the US and Canada are >15 lor one year and S36 tot sheets, etc. Advertisers put a lot of trust in these reader re- three years in Europe Kilobaud erschemt moo- tatiich bei Facfueitschnftenvertneb Monika Nedela. We feel it is in the interests of quests for information. To make it even more worth your while 7778 Markdort. Marhstr 3 Abonnement DM 70 plus Porto 7 20 • gesetii MWST Sir 81 plus Porto 7 20 the whole industry that program- to send in the card, a drawing will be held each month and the Australia For subscriptions write—Katherine Thiikdl. Sontron Instruments. 17 Arawatta St . mers get a major piece of the ac- winner will get a lifetime subscription to Kilobaud! Carnegie Vic 3163 Australia UK £20 ster imgyyear - LP Enterprises 313 Kingston Rd . ntord. tion. The ability to sell micro- Essei. IG1 1PJ. England Please write for other computer systems rests on the ex- foreign rates Second class postage paid at Pete' Reader-service card submission is on the increase, so we had borough nh 03458 and at additional mailing offices cellence of the programs . . . Publication No 346690 Phone 603 924 3873 Ent.re plenty to draw from. Winner of a lifetime subscription to contents copyright 1978 by 1001001 Inc INCLUDE more so than the hardware . . . OLD ADDRESS AND ZIP CODE WITH ADDRESS Kilobaud is Fred Schild of Playa Del Rey CA. Congratulations, CHANGE NOTIFICATION so why not make it possible for programmers to benefit accord- Fred. downtown area . . . and get to What about Radio Shack? the parking lot easily. The ground floor ice-skating rink is ringed by On the way back from San Jose a shopping plaza. Prominent in we stopped off in Dallas/Fort the plaza were a giant Radio Worth. Shack store, a Tandy Computer store and a new Tandy Telephone The next day we had lunch with store. Bill Mueller of ICOM and Art The elevators go up to the 17th Housholder of AGL Electronics floor; from there you have to take in Dallas. A Mexican restaurant an escalator to the top corporate right near AGL was fantastic. I offices. don't care if AGL wants to throw While some firms are being run away their advertising money like by uptight people who appear to drunken sailors in other maga- be well on their way to terminal zines, I'll be stopping by to visit constipation, the Radio Shack at every opportunity. crowd seems to be having a good This is the latest Extensys system. It is approaching the top end in per- From there we waddled on to time at their work. I was sur- formance microcomputers . . . and it isn't cheap, either. This is an ex- Radio Shack and Hy Siegel. prised at the large number of cellent example of how far things have gone with micros. Despite a broken leg, gained a hams involved in the higher posi- tions . . . most of whom have been reading 73 for years. I like that in a person. I've known many of the people either through Radio Shack in Boston or Allied Radio. Quite a crew! Tandy has built two tower buildings recently . . . both about 19 floors. They have a third tower going up soon ... 45 floors. Tandy is dominating downtown Fort Worth. Some difference from when I lived in % g.1133^ the area about 30 years earlier On the right of the PETs being checked out is rack and the highest point in town was upon rack of PETs being burned in. They burn 'em the dung heap at the stockyards. in for 48 hours before packing them up for ship- After the visit to the offices Here's a view of the main part of the PET produc- ment. Normally they have those plastic covers over . . . some talking with various tion department. The front line is brand new PETs the burn-in racks to make sure that the PETs are departments about prospective that are being checked out with diagnostic pro- hot, thus aggravating any troubles that might microcomputer growth ... my grams to make sure they work. otherwise turn up later. software plans, etc., Hy took us off to the plant not far away shown. If your answer is right it plant where the PET is being pro- few weeks earlier on the ice- where the TRS-80s are being will compliment you and then go duced. Commodore doesn't want skating rink in the center of the made. Wow! Again, no produc- on with more instructions. If you me to spill the beans on how Tandy building shopping plaza, tion figures were to be let out of goof, the tape will rewind and re- many units they are turning out, Hy took us all over the new Tan- the bag, but you can see from my play the part you screwed up. but I'm sure you will be able to dy headquarters building. pictures that the production is not How far in the future is all get a good idea from my photos. A few blocks away there is an insignificant. They run the sys- this? Jolt had just such a system They have a big bunch of units enormous parking lot, serviced tems in for 24 hours, so you know up and running two years ago going through the production line by a new subway system that ends all the sets you can see are just a . . . using a Sony video system and then through exhaustive in the Tandy building. This per- part of one day's production. and Jolt microcomputer. Prices testing. The PETs are burned in mits people to park and shop the It was so difficult to tear myself on video recorder systems are for 48 hours at a very high coming down; performance and temperature in order to bring on availability are going up. These any possible failures before ship- would seem ideal mates to our ment rather than after. The small computer systems. And think of number of sets in for repairs in- the data storage on a video dicates the quality control system cassette! is working very well. Jolt was recently bought out by How long does it take to put MOS Technology (Commodore), together a PET? From one end of so we may see some of this the production line to the test technology coming along sooner bench it takes a little over one than we think ... if Commo- hour! With the large number of dore lets the Jolt crew have a free PETs coming out of the factory it hand. is amazing that dealers are groan- ing over their back orders . . . some were telling us they could sell ten times as many as they are Speaking of the PET able to get. The factory will be increasing After the Faire, Sherry and I its production soon, but this still stayed over a couple of days in won't take the pressure off. By Here are over 100 TRS-80s being burned in . . . and this is just one part the San Jose area. We made a next year, I'll bet they have a fac- of the burn-in area . . . which goes on and on .. . and on. If anyone visit to Extensys and then went tory several times as large as they tries to tell you Radio Shack isn't making a lot of 80s in Ft. Worth, tell over to Commodore to see the have right now. him baloney. away from the factory that we knowledge in the hardware area almost missed our plane back to . . . and probably even more Boston . . . and home. engineers interested in picking up on programming techniques. EDITOR'S Those people are, of course, in- terested in reading Kilobaud for TRS-80—Is It Any Good? the same reason as anyone else: articles of general interest, objec- tive hardware and software re- I've had letters from hundreds REMARKS views, and the ads. of TRS-80 owners . . . and A good friend of mine recently talked with dozens at the recent John Craig pointed out something about shows, but I haven't had any cessing) and small businessmen. I Byte and Kilobaud that gave me negative comments yet on the Who Reads Kilobaud Magazine? was rather amazed at the number some food for thought. He held system. Oh, everyone wants more of times I made reference to ar- up a copy of one of the two maga- memory and bigger BASIC, but We not only have a reputation ticles in Kilobaud that would be zines and said, "This magazine is they are amazed at what the 80 for being a magazine for "begin- of interest to those people. almost exclusively filled with can do with what it has—and they ners" in this field—we flaunt it! I These two groups were made esoteric, high-level articles and are having a ball with it. think we need to sit back and ex- up of end users, or the mass very little in the way of light read- In view of this, the recent blast amine just who these "begin- market, we've been talking ing material." in PCC at the 80 is a mystery. The ners" are, however. It's really about. If you stop and think Picking up the other one, he people at Radio Shack were very simple . . . we're all begin- about some of the practical ap- said, "Then we have this one, numbed by the negative review ners to one degree or another. plications programs we've run, which is filled each month with . . . and as bewildered as I by it. The person who just developed hardware and software reviews, mostly light reading, short ar- Yes, the case for the keyboard an interest in building or using a and small-business software, I ticles . . . and very little that you and CPU is plastic, but it is very personal computer, and hasn't think you'll see what I mean. can really sink your teeth into. attractive and it resists dings a lot any background, is most definite- Many see this new mass market Two magazines: one which is too better than metal; and if you want ly a beginner. (And speaking of as being made up of people who technical in content, and the to carry the system around the that type of person: I recently simply want to take their new other too light." He suggested way most of us do, you loudly heard of a company that didn't computer system home, plug it that since Kilobaud, rather than hail the use of lightweight plastic feel they should be advertising in in, load a cassette program and Byte, could more likely balance instead of boat-anchor iron. I Kilobaud because of this "be- run! I agree with that concept things out, I should consider in- carried my TRS-80 with me to ginners' magazine" image. What . . . to a point. That point is cluding at least one or two San Jose ... on to Dallas and a hogwash attitude! Are they go- where these people begin to tire of "heavy" articles in each month's back home. I sure wouldn't have ing to totally ignore that ever- all the "canned" programs they issue. I'm inclined to agree with done that if it had been in a metal increasing segment of the can buy . . . and get the itch to him . . . what about you? (Heck, case. What other computer sys- market?) generate some of their own. this business of putting together a tem can you throw in a suitcase Those "total novice" individ- (That's not hard to imagine magazine is a snap! All you have and take with you? uals need to be examined much because many of the younger to do is provide material that will more closely because they're generation will be programming satisfy tens of thousands of read- coming from several different the home computer to solve ers .. . all with varying interests!) directions and have different ob- homework problems, and there- Byting the Apple jectives in mind. Kilobaud, and by exposing mom and dad to pro- every other magazine in the gramming.) There will be another Since they were giving out free personal-computing field, is be- segment of these end users (most The Southern California copies of Byte at San Jose, I stuck ing bought primarily by com- likely those with an electronics Swap Meet a copy in my flight bag to bring puter hobbyists. Some of those background) who will start back. The price was just right. other magazines purport to be tinkering with the system by add- On the flight, I had the choice aimed at the mass market . . . ing new peripherals, modifica- Got anything scheduled for Ju- of sitting back and resting or those millions of average middle- tions and capabilities. ly 1st? If so, get busy and cancel reading the magazine. I made the class Americans who will be buy- Aha! You know what we're go- it . . . and don't plan to go out of wrong choice and soon got a men- ing home systems in the years to ing to have then? More computer town for the July 4th weekend tal hernia over a review of the come. hobbyists'. I wonder what maga- . . . that is, if you live in Santa Apple II by editor Helmers. The key phrase there is "will be zine they'll be buying when they Barbara CA. If you don't . . . Before reading the Helmers buying." That market hasn't ar- go down to their local computer then, by all means, plan to drive view of the Apple, I had the im- rived yet, but it will—and, need- stores? there for the Southern California pression that it was an excellent less to say, we've all got our eye Now . . . what about some of Swap Meet on July 1st. People system. Many of the computer on it. But for right now (ap- the other "beginners" reading will be coming from as far east as store owners I have talked with proaching the middle of 1978), Kilobaud? I hope computer Phoenix ... as far north as San were very enthusiastic about it, Kilobaud is providing a lot of stores, and readers, are directing Francisco . . . and as far south and it seemed to be one of the best material for this mass market. small businessmen (under 5' 5") as San Diego ... so there's no selling systems on the market I've come to this conclusion as shopping for a system toward reason for you not to come! . . . possibly giving Radio Shack the result of recently teaching a Kilobaud. We're doing our best Next month I'll include a map and Commodore a run for their couple of one-day courses on per- to provide material to help them showing how to get to it . . . and money. The reader comments in sonal computing for the Univer- in selecting a system . . . with ar- a photo of the beautiful building the letters had all been very posi- sity of California. At the begin- ticles written with them in mind. the event will be held in. And, tive, so I was unprepared for the ning of both courses, I opened Now we get to the best part: all that's what it's going to be—an vicious attack in Byte. with the comment that even those professional computer en- event: computer hobbyists, hams Helmers, who, I understand, though I was the editor of a gineers and programmers out and electronics experimenters all got the Apple free, may provide computer-hobbyist magazine, I there who read Kilobaud. You getting together for a good time; an object lesson for manufac- had no intention of directing know, there really aren't that and, without a doubt, that is the turers who are feeling generous. myself to computer hobbyists. many people out there who are most important part. He apparently could see no good Those in attendance included experts in every single area of this Admission will be free ... for in the contrivance. He didn't like newcomers interested in home field. To put it quite simply, there buyers. Sellers can drop me a line computers, students, profes- are a lot of software types who (continued on page 106) sional people (some in data pro- are interested in expanding their (continued on page 110) look impressive, he will apply for before being designed into equip- a bank loan to start production. ment. A suggestion to change the He will usually go to a local bank present "Phase 1" line to "Slow rather than a large bank chain. If Memory" was made by Mr. Chil- the loan is received, Hunt empties dress of Midwest Scientific In- AROUND the business of its equipment and struments. Several others present leaves the area, leaving the credi- agreed that this was a reasonable tors and the bank high and dry. change, since "Phase 1" was a THE INDUSTRY Hunt also orders equipment redundant signal that could be from dealers and pays by check. obtained by inverting "Phase 2," which is also present on the bus. John Craig He then stops payment on the checks. When contacted by a If no objections are found, this dealer about why he stopped pay- change will be considered for ac- The following is from an official pretense thefts amounting to a ment, he may say that the product tion by all manufacturers of the bulletin issued by the Santa Maria quarter of a million dollars in five was defective and is being re- SS-50 bus to make the change of- CA Police Department. different states within the past turned, and request that another ficial. four years, other local, state and unit be shipped. A discussion of possible addi- The DataSync Corp. was start- federal agencies declined to pros- When Hunt was arrested in tions, or changes, to the bus sys- ed in early 1977 by Colonel David ecute him. Santa Maria, he had a loaded tem for MC-6809 processors Winthrop and advertised exten- On February 26, 1978, Hunt, shotgun in his closet at home, and brought up the subject of moni- sively in the national computer who had been serving his term at he may be considered dangerous. tor and software compatibility in magazines. In late June 1977, Chino State Prison, escaped from these machines. It was agreed Santa Maria CA Police detectives a minimum security facility. If anyone has information that may relate to this suspect, please that Mr. Dave Shirk of Technical learned that Colonel Winthrop Hunt is currently being sought contact Detective Ernest L. Systems Consultants, Inc., would had used other names and had by California authorities. Hunt is Kapphahn, Santa Maria Police be asked to recommend jump obtained driver's licenses under a white male, 6' 3", 220 pounds, Department, (805) 922-7811, or table addresses that would be at least three names. Police with reddish-brown hair, and Investigator Zeke Hernandez, used by all SS-50 manufacturers learned that the Colonel had de- hazel eyes. He has worked as a Chino State Prison, (714) in these systems. This would in- frauded a Santa Maria man of TV repairman and has run busi- 597-1821. sure that all users of this ad- vanced processor on the SS-50 bus would be able to interchange hardware and software easily be- SS-50 Bus Manufacturers Meet tween monitors written by dif- ferent sources. All manufacturers of SS-50 bus Mr. Robert Lentz, president of compatible hardware met at the The Micro Works, reported that second Computer Faire in San he had conducted some experi- Jose to discuss possible new bus ments with high speed processors signal assignments. Represented and that he had found no prob- at the meeting were Southwest lems with crosstalk, or any need Technical Products Corp., Mid- for terminations, etc., at speeds west Scientific Instruments, up to 3.0 MHz with a standard Smoke Signal Broadcasting, SS-50 bus. Gimix and The Micro Works. The next meeting of the SS-50 It was agreed the uniformity of Manufacturers Association will be use was essential to protect cur- held at Personal Computing 78 in rent and future users of the bus Philadelphia. All manufacturers from the incompatibility and of SS-50 bus compatible products general chaos now being faced by are invited. All users of the bus S-100 bus users and manufactur- are also invited to participate in ers. It was agreed by everyone the meeting and to send any sug- present that any revised, or addi- gestions they may have to any of tional bus line assignments would the above manufacturers for con- be cleared with all concerned sideration at this meeting. $10,000 under the pretense of nesses marketing CB radios, designing a computer board for computer products and jacks for him, and detectives obtained an trailers. arrest warrant for Winthrop His method of operation has along with search warrants for his been to move to a town under a home and his business. Winthrop new identity, rent a house with was arrested at his business and option to buy and to make con- was held under $100,000 bail. tacts in his field of endeavor A check of Winthrop's finger- (recently, computer hobbyists). prints revealed that his true name Hunt will generally begin his was Norman Henry Hunt, Jr., operation by soliciting backing and that he had been a parole for product design from private violator in California since 1965. parties. Often he will sell his Hunt was charged with three qualifications so well that it is the counts of false-pretense theft as victim's idea to ask Hunt to de- felonies, and he entered a guilty sign a product for him. plea to the charges. Hunt was sen- Hunt may then start a business tenced to two years, eight months and solicit partners. He will rent a in prison on the Santa Maria building, hire employees, begin a charges. Although the investiga- credit line with suppliers. After tion revealed that Hunt had been enough equipment has been re- involved in fraud and false- ceived from suppliers on credit to Inter tec's SuperDEC "pull out the guts & screw in the brains"
While we'll admit the difference in ap- oearance between the DECwriter II and jur new SuperDEC is difficult at best to iee, the difference in performance is as- The SuperDEC Optimizer is designed to tounding! The SuperDEC is our new replace the digital electronics in your rhroughput Optimizer designed to be existing DECwriter II. In less than five jasily installed in your existing minutes, your DECwriter can be trans- DECwriter II teleprinter. Not only can formed into a SuperDEC. The Super- sur SuperDEC Optimizer increase the DEC Optimizer is completely "plug- Drint speed of your DECwriter II by as compatible" with the cables in your Tiuch as six times its original speed, it DECwriter. The only installation tool ilso gives you the features offered only required is one that we give you—a jy our famous SuperTerm teleprinter. screwdriver. Just pull out the guts and :eatures you couldn't get on your screw in the brains. No special technical DECwriter until now. skills are required. And if you get bored 1 ou've undoubtedly already heard of watching your DECwriter print faster >ur Super Term. It's the 1200 baud than you can read, the old digital elec- ;eleprinler that has been replacing tronics may be reinstalled in a matter of JECwriters by the thousands. And minutes. It's really just that simple. while you may have purchased your DECwriter prior to the introduction of Every SuperDEC Throughput Optimizer >ur state-of-the-art SuperTerm, you carries a full one year warranty on all :an now have all of the SuperTerm's parts and workmanship. But our com- ncredible features without having to mitment to excellence in service goes hrow out your DECwriter. beyond the warranty. Intertec can also offer on-site service contracts for all of With the SuperDEC Optimizer installed, your upgraded SuperDEC equipment. rou will have such nifty features as bidirec- So, when you're ready to "pull out ional printing, manual and automatic top of the guts and screw in the brains", orm, full horizontal and vertical tabs (address- contact us at one of the ible and absolute), adjustable right and left mar- numbers below and we'll give |ins, an RS-232C interface, a double wide character you the name of your local et and up to 32 user programmable characters. You SuperDEC dealer. He'll :an also add an APL character set, selective addressing show you what a difference ind an answer back feature at nominal cost. your old DECwriter S395 can make. INTERTEC DATA SYSTEMS
Eastern Regional Marketing Corporate Headquarters Western Regional Marketing 19530 Club House Road 1851 Interstate 85 South 17952 Sky Park Blvd. Gaithersburg, Maryland 20760 Charlotte, North Carolina 28208 I rvin e, C aliforn ia 92714 301/948-2400 704/377-0300 714/957-0300
rhe SuperDEC and other Intertec products are represented in these cities: Albany, NY Alberquerque, NM Atlanta, GA Baltimore, MD Boston, MA Buffalo, NY Charlotte, NC Chicago, IL Cincinnati, OH Cleveland, OH Columbia, SC Columbus, OH Dallas, TX Dayton, OH Denver, CO Detroit, Ml Hartford, CT Huntsville, AL Houston, TX ndianapolis, IN Jacksonville, FL Kansas City, KS Los Angeles, CA Louisville, KY Madison, Wl Memphis. TN Miami, FL Milwaukee, Wl Minneapolis, MN Nashville, TN Mew Haven, CT New Orleans, LA New York, NY Oklahoma City, OK Omaha, NB Philadelphia, PA Phoenix, AZ Pittsburgh, PA Portland, OR Providence. RI Raleigh, NC Richmond, VA Rochester, NY Sacramento, CA Salt Lake City, UT San Antonio, TX San Diego, CA San Francisco, CA Seattle, WA St. Louis, MO Syracuse, NY Tampa, FL Tulsa, OK Virginia Beach, VA Washington, DC. International offices located in Australia, Austria, Canada, Denmark, England, France, Germany, Holland, Switzerland, Taiwan. Photo 4. Larry Lowe, layout, Photo 2. Bob Lentz, president Fig. 1. Shannon Sherrick, daughter of the Malibu draftsman and corporate pilot. and master thinker. 160's designer, Mike Sherrick.
a high-resolution digitized pic- some floodlights aimed at the ture . . . and stored into the subject), then we have a monitor computer's main memory. So for the video, the SWTP system far, so good . . . and, up to now with the Digisector sitting on an things have been quite inexpen- extender board (the right one), sive: the cost of an SWTP 6800 minimum of 18K of main mem- system, a $200 to $300 television ory and last, but not least, the camera, a video monitor for Malibu printer. Add it up . . . $150, $170 for the Digisector it's a heck of a lot less than board and a terminal for the anything you've seen before! computer. Not too bad, right? (The cost of the Digisector board Now we're going to have to includes the computer portrait spend a few bucks for a good software.) high-quality printer . . . and the Photos 2 through 6 will intro- Micro Workers feel the Malibu duce you to the sharp team at 160 is the best for the job . . . Micro Works who put it all to- and from what I've seen, I'll gether . . . and Fig. 1 speaks for have to agree (catch the review itself; The Micro Works/Malibu on that printer in this month's combination is a real winner! (By Photo J. Jill Lentz, marketing, and Ann Curtis, HI secretary. Kilobaud). the way, they have an 8080/S-100 Now, let's do a recap of the version of the board in the works, hardware, while referring to which will sell for about the same torR, which interfaces an inex- Photo 1. Going clockwise, start- Computer Portraits price.) pensive TV camera with a South- ing on the left-hand side of the from Micro Works! west Technical Products 6800 table, we have the TV camera sit- Micro Works, PO Box 1110, system. The TV image is convert- ting on top of the terminal (in- Del Mar CA 92014. Ph: (714) Computer portraits have fas- ed, by the Digisector board, into cidentally, you're going to need 756-2687. cinated me for several years, but not for the reason you might think. The electronics, the soft- ware and the hardware of the system aren't much of a mystery, or a fascination. No, I've always been amazed at the tremendous cost of such systems and knew it was just a matter of time before some enterprising micro enthusi- asts came along and developed one we could all buy. Well, it's happened. Let me tell you about it. . . . In last month's editorial I gave you an introduction to what the folks at The Micro Works are up to. They've been building S-50 6800 boards for some time now (they have an EPROM Program- mer, PROM board, Universal I/O board and extender boards), but their latest is really some- thing! They have developed a digital Photo 6. Bob McMann, tech writer and senior tech- video system, called the Digisec- nician. 8080A/8085 Assembly Lan- of you who have absolutely no ex- guage Programming has many perience in computer program- 55- more points to make . . . too ming and occasionally need to many to cover here. This is not a look up the definition or applica- s O •» one-evening book. If you have an tion of an instruction. Simplified 8080 or 8085 (improved 8080) BASIC Programming is an excel- CPU or have access to one, the lent reference manual. ideal learning situation is to try The first section of the book is the examples as you go along. devoted to an in-depth explana- Each chapter has, in addition, a tion of the operation of a time- series of problems for which sharing system. For those of you clues, but no coded solutions, are who have access to a time-sharing ISE BOOKS supplied. These give you a chance system, this section is invaluable. to try your hand at assembly- For the microcomputer owner, language programming. this section may be skipped as conceivable CPU operation. I Particularly interesting is the your system probably operates in 8080.4/8085 Assembly found the code-conversion and discussion on various program- a substantially different manner. Language Programming I/O information especially inter- ming methods: flowcharting, The second section describes, Lance A. Leventhal esting since my current project is modular, structured and top in easy-to-understand language, Adam Osborne & Associates, Inc. to interface an EBCD Selectric down. Although no one method how most of the instructions are PO Box 2036, Berkeley CA 94702 Data Terminal to my SOL. is touted as being the best, each is used. I say most because in 1974 $7.50, 400 Pages There is hardly a page in this explained, and advantages and BASIC was not as sophisticated book that does not contain at disadvantages presented. Clearly, as it is today. Examples of the use Assuming that there are other least one example program with the author leans toward struc- of each instruction or combina- computer hobbyists who enjoy source and object coding plus tured programming. tions of instructions are clearly assembly-language programming flowchart. These examples are Major statements are printed stated. At the end of each as much as I do, I would like to really subroutines that you can in boldface type, and explana- chapter, a review and a quiz are pass on my thoughts about use in countless programming tions to these statements are provided. 8080A/8085 Assembly Language situations. printed in a lighter type. The The last section of the book Programming by Lance A. A partial list of these subrou- tendency is to read only the bold- contains example programs with Leventhal. tines might include: checksums, face sentences until you come to complete documentation and a I use assembly language in situ- finding a given ASCII character, one that you don't understand, at description of the way the prob- ations where BASIC won't do the changing the parity of a string of which time you read the lightface lem was solved. job, such as graphics, input- characters, ASCII-to-decimal type for clarification. Out of This book is a good reference output, or where BASIC pro- conversion, addition, subtrac- habit, 1 found myself reading it for those of us who can't seem to grams won't fit due to memory tion, multiplication, division, all. remember whether a comma or a size limitations. In addition to the sorting, indexing a table, code This is definitely a software- semicolon is necessary to print usual I/O operations (keyboard, conversion and so much more. In oriented text, but an amazing closely spaced output, or any printer and video), I turn various fact, the emphasis in chapters 5 to amount of hardware information other syntax problem that may external devices on and off under 12 is on subroutines that can be is given in the I/O and interrupt drive you to the brink of insanity. computer control. This requires combined to form more complex chapters—probably enough to Although Simplified BASIC being able to manipulate CPU programs. implement any of the designs dis- Programming is available registers, addresses and data Chapters 13 to 16 tie together cussed. through any bookstore, you may lines; it takes assembly-language everything you have learned. This So far, I have covered all the find a used copy for sale at sub- programming to do this. is the dessert course. My assem- book's good points but none of stantial savings at your friendly, I have written many programs, bly-language programming tech- its bad ones. That is probably neighborhood college bookstore. but after skim-reading this book I nique always started with coding because I couldn't find anything And if you are really watching realized that I have missed the after some sketchy mental prob- to criticize. My only negative your budget, you may find significance of, or misused, many lem definition. Dr. Leventhal has reaction has to do with 8080A/ Simplified BA SIC Programming, 8080 instructions. A second, convinced me that this is wrong. 8085 Assembly Language Pro- along with other informative more thorough, study confirmed Problem definition and program gramming having been advertised reading on BASIC, at your local this and contributed greatly to my design should come first, fol- as available in October 1977, library. assembly-language programming lowed by coding, debugging, test- which is when I ordered and paid Jim Cambron ability. ing, documentation, mainte- for it; it was actually not printed Topeka KS Table 1 is an outline of the con- nance and redesign. until late January 1978, which is tents of Leventhal's book. Just when I received it. about every possible question In my opinion, 8080A/8085 that you could come up with is Assembly Language Program- 1. Introduction to assembly-language The 8080A Bugbook answered in one or more of these ming is a worthwhile text; and programming chapters. Chapters 1 and 2 serve Rony, Larsen, Titus 2. Assemblers I'm hoping for a Z-80 version as the appetizer—a comprehen- soon. If my technical library had Howard W. Sams & Co., Inc. 3. 8080/8085 insiruction sets Indianapolis IN sive discussion of assembly- 4. Simple programs to be reduced in size for some language programming and as- 5. Simple program loops reason, this is certainly one book $9.95, paperback semblers. 6. Character-coded data I would keep on the shelf! 7. Code conversion One book out of a hundred Chapter 3 does more than just 8. Arithmetic problems Rod Hallen list the instructions with a brief 9. Tables and lists Tombstone AZ makes you wish you had seen that description; a half page or more is 10. Subroutines one before slogging through the devoted to each instruction and 11. Input-output other ninety-nine. This is such a explicit examples promote better 12. Interrupts book. It should be subtitled "All 13. Problem definition and program Simplified BASIC Programming understanding. Nowhere else You Wanted To Know about the design Gerald and Joan Silver have I seen the 8080 instruction 8080 and Its Support Chips, but 14. Debugging and testing McGraw-Hill, New York set explained with such detail and Didn't Know Where To Look." 15. Documentation and redesign 1974, $12.85 clarity. 16. Sample projects In the Bugbook tradition, the Chapters 4 to 12 are the main 8080A neatly balances theory and course; they take you from the Table I. Simplified BASIC Program- practical example. It comprises simple program through every ming is an excellent text for those eight chapters with titles such as, "What is a Microcomputer?" MOV M,A are 176 and 167, re- the Altair bus structure and have much about either one. and "An Introduction to Micro- spectively, much easier to remem- a high regard for IBM, you won't The idea behind these books is computer Programming." They ber than two dissimilar hex codes. enjoy reading this book. that you can buy Vol. 1 if you're are all informative and readable. The book's overall theme is A little more than half of The in the first category. Vol. 2 if Unfortunately, there are some that the microprocessor is a use- Home Computer Revolution is you're in the second category, or errors (no doubt accidental, but ful tool. No mention is made of related to the author's predic- both if you're in the third possibly confusing to the reader). high-level languages, games or tions of the future home-comput- category. Occasionally, the authors give a heavy number crunching; the in- er world. Therefore, if you are That's the idea behind the detailed explanation that ends terfacing is to practical devices going to read this book, do it books, but how well do they pull just when you expect some vital and the programs are in simple now; very shortly, these precari- it off? Pretty darn well, I'd say. truth to be revealed; but these machine language, all designed to ous prognostications will either Together, the two books repre- rare omissions serve mainly to "do something." And although be history or wrong guesses. sent a heavily edited transcript of demonstrate the thoroughness of the special 8080 support chips are Some of the predictions concern- nine days of conversation be- the rest of the book. all covered in some detail, TTL ing future home-computer input/ tween two people on the subject Each chapter begins with an alternatives are explained where output devices and techniques of home or hobby computing. outline and ends with a summary they can be applied. seem way out (but so was 1984 One of the participants (called and some searching questions. In It is difficult to classify this as not very long ago). "A" because he provides the light of its format, it could well be either a hardware or a machine- On the positive side, I thought answers) has a strong back- used as a textbook. Let's take language software book, since it the historical notes on Mits, ground in computing in general chapter 4 to consider the book's is really both. If the reader could Cromemco and other companies (both hardware and software), style. previously build a kit or follow a were very interesting. Those read- and home computing in par- program, he should, after digest- ers new to home computing will ticular. Title: Generating an output pulse. ing this volume, be able to design find some seldom published The other participant (called Outline: Objectives, definitions, much of his own hardware and background information. "Q") is an intelligent, interested 8080 I/O instructions, device write programs to interface with There are brief hardware de- newcomer to the field who has select, pulse decoding, sample other devices. That's a lot to learn scriptions (Altair bus oriented), visited the computer stores, microcomputer program, de- for only ten bucks. but with home computing mov- picked up some literature and vice select pulses as control ing so fast, a book would have to bought a few magazines, but pulses, example, test, and Ernie Bruoner be published in loose-leaf style needs further help to figure out "What have you accomplished Lakeside MT to keep up with the hardware what it all means. He doesn't in this chapter?" changes. Only a monthly maga- understand too much of what Introduction: "In this chapter zine, such as Kilobaud, can hope he's read, and wants to know, for you will learn how to generate to keep you informed on the cur- example, what is really involved device select pulses ..." The Home Computer Revolution rent hardware. in putting a computer kit together. At the end of the chapter the Theodor H. Nelson Is he better off getting a fully reader is asked to "draw a The Distributors, The program-languages de- assembled system? Why are there schematic diagram for a circuit 702 So. Michigan South Bend scriptions are short, with most so many different microproces- that can generate up to 256 dif- IN 46618, $2 languages getting only one para- sor chips? What does all this ferent device-select pulses." graph. The author suggests that a person learn programming with a RAM/ROM/PROM/EPROM And if you read the chapter you Most computer hobbyists, or BASIC interpreter, and this is stuff mean? What's involved in should be able to do the above, those about to get into comput- probably what most home com- programming? Why are there so and a great deal more. ing, will find this book easy to puterists are doing. many different programming In following chapters the read, as well as entertaining. It is A serious oversight occurs on languages? What can you really authors explain the use of these neither a technical book, nor a page 117. Add the following to do with a home computer? and other signals for the control dry history book. The author has the lists of available magazines on 1024 is 210, which is the number of outside devices via timing combined semitechnical material, that page: Kilobaud, Peter- of questions and answers in the loops and other programming se- computer-historical anecdotes borough NH 03458. two books—thus the title for the quences. Throughout, however, and his forecast of the role of the The Home Computer Revolu- work. But it's more than just a they stress keeping the hardware computer in the future. tion is light reading and generally bunch of disjointed questions simple and exercising control by Reading this book, I found entertaining; one of my next thrown together. The books are software. that my level of interest wavered reading projects will be Comput- well organized and proceed I appreciated most of the between near boredom to moder- er Lib ($7, same source), which is logically from one topic to the simplified, no-mystique ap- ate interest. However, because of referred to often in this latest next, building up your knowledge proach to several things that had the nature of the material, an- book by Theodor Nelson. and tying things together as you long bothered me—among these other reader might find different Gordon Flemming read. were flag testing, the use of status peaks and dips of interest. Sylmar CA Of course, neither book is go- words, and the inside working of For instance, as an advocate of ing to enable you to become a the many conditional branch in- the Altair bus, I reacted favor- professional programmer or structions. The entire instruction ably to the author's repeated sup- hardware designer overnight, but set is covered in greater detail port of this configuration. A they'll give you a better idea of Home Computers: 2" than I had previously encoun- reader using the Digital Group what these people do, and intro- Questions and Answers; tered. It is methodically consid- bus, for example, might be disin- duce you to some of the basics as Vol. 1: Hardware ($7.95) ered by function—by grouping terested in the Altair bus they relate to home computing. Vol. 2: Software ($6.95) the related logical operations, for coverage. Rich Didda) dilithium Press Usually, when I read an intro- example—and whole pages are At the other end of my interest Forest Grove OR 1977 ductory level book or article on devoted to illustrating certain in- spectrum, I found the frequent computing, I find myself saying, structions that might be consid- attacks on IBM to be objection- "That's not a very good ex- ered tricky or difficult. able. I have no particular like or These two books fill a definite ample," or "Boy, that's sure go- The use of octal may disap- dislike for IBM, but I certainly need. Most people who get start- ing to mislead somebody." These point some readers. The explana- found the repeated negative atti- ed in the home-computer field books are a rare exception. The tion is that the 8080 instruction tude distracting. find themselves in one of three questions and answers both have set was designed this way. Logical It's a matter of psychology—if situations: They know quite a bit a nice balance of simplicity, ac- operations all begin with 2 in oc- you like the Altair bus and have about software but nothing about curacy, and (amazingly enough) tal, and MOV instructions with 1. something against IBM, you'll hardware; they know quite a bit realism, and actually convey the The accumulator is 7 and the enjoy the author's comments; on about hardware but nothing memory 6. Thus, MOV A,M and the other hand, if you don't like about software; they don't know (continued on page 111) Radio Shack's personal computer system? This ad just might make you a believer.
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6 V requiring no adjustments, Plotters—Kit and Assembled and a higher video output signal. The circuitry has been simplified Sylvanhills Laboratory, Inc., for easier assembly, and a two- has been sold to Pitsco, Inc., and level TTL output is supplied for offers plotter kits and plotters interfacing. In addition, a power completely assembled. The kits board is supplied so only a 5 V, 1 require the purchaser to mount Amp power source is needed, them on a drawing surface (con- and, in the near future. Solid sole also available as a new prod- State Sales will supply a computer PerCom's LFD-400 system. uct of Sylvanhills) and to do the interface card. interconnection between the con- This kit includes all semicon- trol/status registers and the next the drive and drive power supply. trol PC boards and his computer. ductors, boards, data sheets, dia- 8 access the transmit/receive data System components may be in- Plotters require an 8 bit parallel grams, resistors, capacitors, and registers. This map arrangement dividually purchased, and 2- and I/O port and 5 and 24 V power an 8 mm lens. Assembly has been allows optimum use of indexed 3-drive systems are also available. sources. A basic 8080 software simplified so that the only equip- addressing in I/O intensive sys- The controller board, which is program is included in the ment needed is an oscilloscope, tems and permits the use of a very installed in an SS-50 bus slot of owner's manual. soldering iron and some wire. tight interrupt polling loop. the host computer, includes Sizes available are 11 x 17 ($795 The complete kit sells for $349 The standard configuration of special low-voltage-drop regu- in kit form), 17 x 22 ($950 in kit ($75 to assemble and test). the 9650 is fully populated to 8 lators, a proprietary "bit shift- form) and 22 x 34 ($1300 in kit Solid State Sales, PO Box 74K, channels. Prices range from $395 ing" compensation circuit, an in- form). Consoles priced separately. Somerville MA 02143. in single quantities to $237 at 100. activity time-out circuit to in- Contact the new offices and A partially populated 4-channel crease drive motor life, and pro- manufacturing facilities of version is also available at lower vision for 3K bytes of PROM. Sylvanhills Laboratory, Inc., PO prices. The LFD-400 PROMware DOS, Serial Interface Module Box 646, Pittsburg KS 66762. The 9650 is one of a family of miniDOS, allows SS-50 bus M6800 support modules. All owners to use their existing soft- The 9650 is an asynchronous cards of the family are 6.05 inches ware with simple patches. This serial interface module specifical- by 9.75 inches and utilize a 43-pin was a priority consideration in 202 Video Camera Kit ly designed for compatibility with dual readout edge connector with the development of miniDOS. the M6800 microprocessor bus. It 0.15625 inch pin spacing. The LFD-400 uses the Shugart Solid State Sales 202 Video is pin and outline compatible with Creative Micro Systems, 6773 SA-400 drive. Disk speed is 300 Camera Kit may be used for visi- the Motorola EXORciser and Westminster Avenue, Westmin- rpm, which gives a data-transfer ble or infrared viewing for char- Micromodules and with the ster CA 92683. rate of 125 kilobits per second. acter recognition with computers MEK6800D2 Evaluation Kit. It The read/write head is stepped with external circuits. It will oper- features full address decoding from track to track at 40 ms per ate in a vacuum, under water, at and fully buffered data, address step. The SA-400 drive system Disk Storage System high altitude or in a magnetic en- and control lines. This module features a positive media in- for the SS-50 Bus vironment because there is no utilizes 8 MC6850 Asynchronous terlock, which prevents door high voltage or magnetic deflec- Communications Interface closure on a misaligned disk, and tion. In addition, it may be used Adapters with full RS-232C sig- PerCom Data Co.'s LFD-400, write protection circuitry. The for IR surveillance with an IR nal conditioning. An on-board a minifloppy11 disk memory LFD-400 storage media is a light source, and is excellent for bit rate generator simultaneously system for the SS-50 bus, includes 10-sector hard-sectored minidisk- standard surveillance work be- provides 14 standard rates that a controller PC board, PROM- ette, which accommodates 89.6K cause of its light weight (under 1 can be individually strapped to ware disk operating system, disk bytes of data on 35 tracks. The lb.) and small size. each ACIA. drive and drive power supply, in- recording technique is Bi-Phase- Some advantages offered in The 9650 occupies 16 consecu- terconnecting cable, two mini- M (also known as "double fre- this new kit from previous models tive memory addresses. The low- diskettes, an operator's manual quency"). are all clock voltages operating at est 8 of these access the 8 con- and a compact enclosure to house PerCom Data Company, Inc., 318 Barnes, Garland TX 75042.
CT Terminals
COMPUTER TEXTile an- nounces its line of high-quality hard-copy hardware. CT sells re- conditioned QUME and Diablo daisy wheel printing terminals, which feature 30-cps printers, 96-character keyboards with 10-key numeric pad, ASCII cod- ed, RS-232 interface. Also included are 256-charac- • *
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Wintek's analog interface module.
desk is sturdily designed to last a long time under normal condi- ter buffer, user's and service ity for maintenance, mechanical time. The complete plug-in inter- tions. manual, with full graphics capa- door interlock with a manual face with software sells for Computer Systems Design, bility packaged in a cabinet with override button, targeted media $49.95. 1611 E. Central, Wichita KS black-and-chrome-wheeled ped- loading, and a patented "wear- Microproducts, Dept. K, 1024 67214. estal. Options include 45-cps and free" diskette hub rated for over 17th Street, Hermosa Beach CA 55-cps mechanisms for some 100,000 insertions. Prices for the 90265. QUMEs, other encodings, pin- Innovex Series 400 range from Microprocessor Analog feed platen, tractor forms feeder $575 in single quantities to $435 interface Module and service contracts. each for orders of 100. Microcomputer Storage System Each terminal comes with a Innotronics Corporation, The Wince Analog Interface limited 30-day warranty. Quanti- Brooks Rd., Lincoln MA 01773. Module makes it easy for labora- ties are limited. Prices from The Computer Systems Design tory and control engineers to in- under $2000. Also available are Microdesk is a new addition to terface thermocouples and other Kilobaud's microcomputer lab. reconditioned ADM-ls, modems Printer Interface for Apple II transducers to a microprocessor. and paper tape punch/readers. (We ran a release on the Micro- It makes it equally easy to inter- COMPUTER TEXTile, 10960 desk in November 1977; now face the microprocessor to Wilshire Blvd., Suite 1504, Los Microproducts has announced we've had a chance to utilize it.) motors, servos, etc. Options in- Angeles CA 90024. a printer interface for the Apple The desk's ease of assembly clude a 16 channel multiplexer, II computer which is compatible makes for a quick and useful ad- an 8, 10, or 12 bit analog-to- with the Southwest Technical dition to any room, with one ad- digital converter, and one or two Products PR-40 Printer. It will be justable shelf that you can ar- 8 bit digital-to-analog converters. Innotronics Floppy Disk Drives marketed as a preassembled PC range to your specific needs. Be- The base price is $99. Other board that plugs directly into the cause of its air-vented design, the Wince Modules include the Con- Apple II computer, an intercon- upper shelf is an excellent loca- The new Series 400 diskette trol, RAM, ROM, EROM Pro- necting cable and a cassette con- tion for your unit. You can keep grammer, CMOS RAM/Battery, drive, offering an array of new taining the operating software. the unit close at hand without its features that were previously un- Driver/Sensor, Console I/O, The printer prints one line at a being in the way. There's plenty available in the market, has Cassette Interface. time when the return key is of room for your terminal, and a recently been introduced by In- Wintek Corp., 902 N. 9th St. struck. The printer subroutine sliding keyboard shelf can put the notronics. Unique new features Lafayette IN 47904. can also be called in BASIC to keyboard within comfortable include automatic head-unload print the entire contents of the reach—or out of the way when and stepper motor time-outs, video screen. While in the BASIC you're not using it. bidirectional write-protect, radial The Stringy Flopp> mode, using the list subroutine, The lower shelf fully handles stepping ability for truly overlap- the printer will continually record the task of holding all the ping seeks, host power-failure the program, while the video manuals that accompany a small detector and six different LED The Exatron Stringy Floppy™ screen scrolls up one line at a microcomputer lab. The Micro- activity indicator electronics. is a subsystem consisting of a con- Both the Model 410 (soft- sectored, IBM-compatible) and the Model 420 (hard-sectored) provide single- and double- density recording capability. In addition, a proprietary data sep- arator design, coupled with a digital noise filter and a unique way of handling recorded signals, results in 35 percent greater data integrity margins. The Series 400 also incorpo- rates the field-tested Innovex mechanical design, which in- cludes filtered air operating en- vironment, single-side accessibil- 8085 + PASCAL = 85/P
The new 85/P, programmer's workbench from Northwest Microcomputer Systems, Inc., combines the throughput of the 3 MHz Intel 8085 and the power of PASCAL. The standard system features: (1) 8085 CPU with 54K bytes of static user RAM; (2) one mega- byte of storage in two double- density Shugart floppy-disk drives; (3) 24 x 80 high-resolution display with 103 station Hall ef- fect keyboard; (4) two serial ports Central Data 2650 Computer System. Northwest's 85/P. for printer and second terminal or modem; (5) a choice of attrac- tive solid oak or walnut cabinets trol board connecting to the Sta. A, Champaign IL 61820, of- board and video monitor. that enhance any home or office. S-100 bus, a small drive module fers a 16K RAM board specially The Naked Terminal, priced at outside the computer mainframe designed for use in S-100 com- $395, displays 80 characters by 24 The 85/P gains its efficiency in and the connecting cable. puters. The dynamic memory lines, using both uppercase and program preparation and code The individual continuous- board uses a reliable refresh lowercase characters in a 5 x 7 execution from the increasingly loop tape wafer, less than a method that inserts cycles be- font. Half duplex, full duplex popular PASCAL language. The fourth the bulk of the standard tween the computer's normal ac- and a block mode that allows 85/P provides the full PASCAL audio cassette and holding up to cess cycles. The 16K RAM board editing before transmission are environment including a 700 1pm 40K bytes, is inserted in the slot in uses less than one-half the power features of the Naked Terminal. compiler/interpreter, random the front of the drive module, and of a comparable static RAM Editing is aided by an addressable and sequential files, a screen- will save or load 4K bytes in board. cursor. oriented editor, interactive, about 5 seconds. All operations CD's board comes completely Switch-selectable features in- source-linked debugger, plus full are software controlled; the utili- assembled, tested and burned in clude black-on-white or white- documentation and a 90-day war- ty programs are contained in an —just plug it in and start using. on-black, blinking or nonblink- ranty. EPROM on the control board. Each board also comes with a full ing cursor, and variable baud The complete system costs The subsystem is delivered ready one-year warranty. Price is $289. rates. $7495. Delivery is quoted at 30 to to operate, and is backed by a There is capacity on the board for No software is required. The 60 days, with Northwest Micro- one-year full warranty and a up to 32K RAM ($475), or add Naked Terminal can be config- computer Systems paying for de- 30-day money-back guarantee. 16K for $200. ured by DIP switch to drop into livery on any order shipped later Exatron Corp., 1030 East S-100 extender board, assem- an existing system, replacing the than 60 days. A variety of options Duane, Suite I, Sunnyvale CA bled and tested, is $110. The 2650 serial I/O card and stand-alone is available. 94086. Computer System board retails terminal without making any Northwest Microcomputer for $275. System board features changes to software. Systems, Inc., 121 E 11th, include: 80 x 16 line display, 2650 The Naked Terminal is a com- Eugene OR 97401. microprocessor, 300 baud cas- plete dumb terminal on an S-100 The Electric Pencil U sette interface, supervisor pro- board. It contains a microproces- gram, two parallel ports, one in- sor with its own memory, its own 'Byte-Size Breadboards" Michael Shrayer Software, put and one output, and 2048 software drivers and its own in- from CSC 3901 Los Feliz Blvd., Los Angeles bytes of read-write memory. ternal bus. It won't take up any CA 90027, announces the Electric of the 64K memory address space Pencil II. Some of the new fea- of the S-100 bus. The age of LSI has put a lot of tures include: CP/M compatibil- Like all Dynabyte products, power in Lilliput for users of Naked Terminal Cuts ity, simple file management, the Naked Terminal is completely Continental Specialties Corpora- Dumb Terminal Costs Vi dynamic print formatting, multi- assembled, socketed, tested and tion Experimentor Socket solder- column printing, cassette backup burned in. Dynabyte's guarantee less breadboards. This seems es- capability, centering, underlining Dynabyte, Inc., lowers the cost is for a full year—the longest in pecially true for the palm-size and boldface. of a dumb terminal with its the industry. EXP350 and EXP650. Each is The Electric Pencil II is now Naked Terminal, an S-100 Dynabyte, Inc., 4020 Fabian, just 3.6 inches long. The EXP350 available on CP/M—standard module that functions with a key- Palo Alto CA 94303. offers .3 inch center spacing to printer versions $225; Diablo printer versions $275. System hardware must include: 8080 or Z-80 based microcomputer, printer, video display, CP/M supported disk system, or North Star minifloppy disk, or cassette interface (Tarbell or SOL). The Electric Pencil I is still available for non-CP/M users. Contact Michael Shrayer for more information.
Central Data Boards
Central Data, PO Box 2484, Dynabyte's Naked Terminal. The EXP650. accept standard DIP packages; the EXP650 offers the wide .6 inch spacing appropriate to wide LSI DIPs. Their small size offers the perfect opportunity for byte- size modularity. This can happen in several ways. A complex LSI function IC like a UART, for example, can be ac- commodated, along with perti- nent support discretes and con- necting cables as a module on a CSC EXP650. An LSI function can be synthesized with less com- plex circuitry. A counter, decoder and display, for example, can be ment system; text editor; and cessories includes a numeric pad, combined on a single EXP350 linking loader. custom cables and connectors. n p-i and treated as a unit—as can a RCC offers a wide range of op- The versatile interface allows user data converter, an interface cir- tions for the REX system, in- selection of parity, positive or I,... . i.. cuit or any of a number of func- cluding b & w or color video negative logic data and strobe tional modules. monitors, rf modulator genera- outputs, alpha lock operation CSC's EXP350 is priced at tor, expansion microfloppy and both dc level and pulse strobe $5.50 (unit), the EXP650 at drives, RAM memory to 64K on signals. A latching shift lock key $6.25. the motherboard (no bus slots is included, and all outputs are Continental Specialties Corpo- needed), a 120 cps 80/96 column TTL-DTL-MOS compatible. Kit LUU ration, 70 Fulton Terrace, New printer programmable serial is $64.95; assembled and tested communications channel, and a model, $75.95. A matching en- Haven CT 06509. Bottom oscilloscope signals show data communications modem. closure, Model 702, is $29.95. noise reduction made possible by The REX system lists for $2495, George Risk Industries, Inc., the Glitch Grabber. assembled and tested only. REX Computing System GRI Plaza, Kimball NE 69145. Realistic Controls Corp., 404 W. 35th Street, Davenport IA supply for MOS Technology RCC introduces REX—the 52806. KIM users, and for others need- Computer-related Cases total microcomputer system, ful- ing a 5 volt and 12 volt regulated ly assembled, complete with a supply. The model 512 comes Z-80 CPU, 24K of RAM, video The Buckeye Stamping Com- completely assembled and in- New Model 756 output, system keyboard, a pany, 555 Marion Rd., Colum- Full ASCII Keyboard cludes a total 4.3 Amp capacity microfloppy disk drive featuring bus OH 43207, now offers instru- and additional 8K memory. double-sided recording, cabinet ment cases with keyboard holders The K L power supply features and power supply. The Model 756 keyboard from and CRT canopies. These com- + 5 volts regulated with 1.4 Amp The REX system includes an George Risk Industries provides puter-related additions, fabricat- maximum, + 12 volts regulated S-100 motherboard containing encoding for all 128 ASCII char- ed of durable, extruded alumi- with 1.0 Amp maximum, +8 volts the CPU, video display interface, acters and control functions, im- num, are offered in standard 17 unregulated with 4.5 Amp max- bootstrap and Monitor PROM, posing no limitations on software inch widths. The new cases are imum, and + 16 volts unregulat- and powerfail and vectored inter- design or hardware capability. now offered with blue or black ed with 1.0 Amp maximum. It rupt circuitry. The system comes Utilizing reliable IBM series key- vinyl tops with matching feature has regulated outputs with cur- complete with a modern walnut- switches and low-power MOS en- stripes, or with teakwood vinyl as rent limit and thermal overload sided cabinet and a 15 Amp coder circuitry, Model 756 is de- an option. protection, fuse-protected power supply, and includes space signed to bridge the gap between The new Buckeye computer- primary, ac line cord, and con- for a second microfloppy drive basic keyboards and expensive related cases sell in small quanti- nector cable. plus five slots for S-100 bus custom OEM models. Assembly ties in a price range of $110 or options. and mounting are simplified $215, complete. The unit is enclosed in a Bake- A complete line of low-cost through OEM industrial grade lite case with aluminum bottom software options is available. components and a rugged MIL- plate and rubber feet. It is 6.8 x These include ANSI FORTRAN grade printed-circuit board. The 5.6 x 3 inches and weighs 3.5 lbs. IV with subroutine library and durable circuitry is complement- Power Supply for KIM Price is $37. 8080 and Z-80 extensions, includ- ed by custom molded keytops and ing advanced math and string- a line of heavy-gauge steel en- K L Power Supplies, PO Box handling functions; floppy-disk closures for desktop use. 86, Montgomeryville PA 18936, New "Glitch Grabber" operating system; file manage- The 756's complete line of ac- announces the model 512 power from Extensys
A board interconnection de- vice from Extensys Corp. signif- icantly reduces noise, glitches and jitter on the S-100 microcomput- er bus and carries a suggested retail price of $79.50 in single quantities (large-volume dis- counts available). Called the "Glitch Grabber," the printed circuit edge-connective device maintains clean signals on the notoriously noisy S-100 bus, safe- guarding the low tolerance volt-
(continued on page 111) (like those of the 1N444X family) on a typical case (not necessarily at a forward current of .1 mA the worst case) and experimental have a static forward voltage of trial. I built my first crystal set in maximal .55 volts (these figures 1933 and also know about ger- come from the TI manuals). manium and use IN695s if If now the output of a TTL nothing else will work for a gate is driving the input of a fol- "quick and dirty" NOR. Many lowing gate via a decoupling computer mods, where only a diode, the low-level input voltage single extra input is needed, can for this gate can be .5 plus .55 or be quickly solved with a single 1.05 volts or even higher, depend- diode, and some of ours have doors. And try to stay upwind PC Board-makers, Take Note! ing on the size of the pull-up been working for years with no . . . If you must work indoors, resistor. The maximum permis- problems. make sure there's plenty of ven- sible low-level voltage for all When designing from scratch, Your otherwise fine article on tilation—not just from an open devices of the 7400 and 74LS I presently prefer CMOS, but making printed circuit boards window or two, but from a strong series, however, is only .8 volts. when modifying someone's de- (Kilobaud, April 1978) fails to window exhaust fan. That means this arrangement sign, any trick of the trade is valid give instructions and precautions • "Wear neoprene rubber gloves operates in a voltage range that is in my view. Diodes often solve a for handling the chemical used to and goggles. If you splash your- outside of the manufacturer's problem simpler than any other develop the photoresist-coated self, wash the affected area im- specifications. The circuit may approach. Diode ANDs are still boards. The resist developer mediately with soap and water. work sometimes, and then it may another method where input recommended is of completely • "Keep children away from the not work, depending on the whim switching matrices for memory different nature than the chem- work site, and store the container of the ICs, power buses, tempera- use can be implemented such as in icals normally encountered by the out of their reach." ture and phase of the moon. Don Lancaster's TTL Cookbook home photography enthusiast. The developing of the photoresist That's the reason diode logic (Fig. 6-27, p. 256). I'm sure that your readers are could easily be performed safely with TTL devices having a nor- aware that the resist developer is Ralph W. Burhans in the backyard after sunset. The mal (totem-pole) output should flammable and will take precau- Athens OH photoresist is not so light sensi- not, I repeat, not be used (unless, tions to exclude potential ignition tive that night background il- maybe, you are using hot carrier sources. They may not be aware lumination would be a problem. diodes, which have a lower for- that methylene chloride is the ac- None of the chemicals used in ward voltage but are very expen- Due Credit tive ingredient in paint remover. this process should be stored in a sive, or germanium—remember As such it will rapidly ruin any refrigerator that contains food, germanium—diodes, which are painted or varnished surface with Just received Kilobaud No. 16 and flammable chemicals should slow). which it makes contact. A more yesterday; the article was in there. never be stored in any home serious consequence of splashes is Erich A. Pfeiffer What a good feeling, until I refrigerator. that the developer is a serious skin Granada Hills CA spotted the title block. Oh my! With these precautions and and eye irritant. new 4K EPROM board from common sense, printed circuit SWTP Methylene chloride is an ex- boards can safely and successful- tremely volatile liquid. This Ralph Burhans' Reply ly be made at home. Credit needs to be given where means that a room containing an credit is due. open tray of the developer solu- Jim Warner tion would rapidly have its air Board of Studies in Chemistry The critique of "The Wired new 4K EPROM board from contaminated with substantial University of California OR . . . Again!" is perfectly cor- APTEC amounts of the vapor. In a small Santa Cruz CA 95064 rect in stating that use of diodes in series with normal totem-pole The goof was not in the proof bathroom with the windows and copy I received because no title doors closed to make a temporary TTL output (not O.C.) could create problems in excessive zero block was included. darkroom, the vapor concentra- The Wired OR . . . Again! Harley D. Johnson tion could far exceed the recom- voltage drop and is not recom- Oregon City OR mended peak exposure level. The mended by chip manufacturers. present federal peak limit is 2000 I read with interest R. W. Bur- However, experimenters often do ppm, but the National Institute hans' letter (p. 21) regarding the what is possible and not what is wired OR in the December 1977 recommended, particularly if the for Occupational Safety and 8080 Simulator Notes Health has recommended that it Kilobaud and would like to inject risk of failure is very small. be substantially reduced. some word of warning. The wired Before the widespread use of OR (or, more correctly, wired MSI and LSI, many of us used I want to commend your maga- Methylene chloride, which NOR), when used with TTL de- Don Lancaster's technique (TTL zine and Lee Stork for a func- enters the body by inhalation, is vices, should be used only, I Cookbook, Fig. 3-18A, p. 146) tional and useful program/article rapidly metabolized. One of its repeat, only with open-collector where a 74154 decoder is used to on the 8080 Simulator (Kilobaud, breakdown products is carbon J types. The M L logic (I love Don address a diode ROM matrix with September 1977, p. 64). After de- monoxide. This reacts with the Lancaster's term) or diode logic a lot of NOR intersections. These bugging I was able to adapt this hemoglobin in blood and reduces should be used only, I repeat, work quite well, and I don't recall program to an Intellec 8/Mod 80, its oxygen carrying capacity. The only with CMOS devices (which any failures. With the 74LS138 to which 1 have access. For the heart and circulatory system must have logic levels much more for- mentioned previously, a two benefit of readers who have tried, then work extra hard to pump giving than that of TTL) or if the diode NOR with one pull-up re- or are going to try, this program, blood faster in an attempt to input consists of a switch. sistor provides elegant simplicity here are a few notes: make up for the decreased oxygen Anybody who follows Mr. driving a D input on a KIM 1. At address 134, the mne- supply. Methylene chloride also Burhans' advice and uses diode 74LS145 with no problems in my monic LSI should be LXI. affects the central nervous system isolated AND or OR configura- limited experience with four or 2. At address 172, MVI B, 5 as an anesthetic. tions with normal (totem-pole five different chips. was necessary to send a line feed I recommend that anyone us- output) TTL gates of the 7400 or It is also correct to state that to my console output device (a ing a developer containing 74LS family is asking for big CMOS has essentially no prob- CRT terminal). methylene chloride follow the trouble. The reason is simple: lem ... so where is the argu- 3. Likewise, address 138 need- general recommendations for The worst-case low-level output ment? The basic difference in our ed MVI B,2 to give me the prop- paint removers in Consumer voltage for gates of the 7400 thinking is perhaps that adverbs er display format. Reports (August 1976, page 434): family is .4 volts; for 74LS family like "no" or "only" are applied 4. At address IFD, my ICOM • "If at all possible, work out- it is .5 volts. Fast silicon diodes here with some judgement based FDOS II assembler creates a 108 contains errors in syntax, es- month or so . . . doing some- OUTPT: IN 1 ;GET STATUS BYTE pecially on line 72, which calls for thing . . . should be a piece of ANI 4 ;MASK BYTE a function not directly executable cake . . . you could add . . . and JNZ OUTPT ;LOOP IF NOT READY on these machines within the you would be able to have . . . MOV A.M ; READY FOR DATA number of steps allotted, and on the schematic . . . was not avail- ANI 7FH ;ZERO PARITY BIT CMA MNVERT BYTE line 63, where no error halt at a able ... at some time in the OUT 0 ;SEND IT TO PORT 0 "flashing 9.999 999999 99" will future will be invaluable. Etc. I DCR B ;DCRM. LOOP CNTR occur, at least on the TI-58/59, am keenly interested in this sub- RZ ;RETURN IF DONE unless an R/S is provided or flag ject and just wanted to express INX H ;GET NEXT CHAR. IF 8 is set. Furthermore, even after my disappointment. ;NOT DONE all syntax is corrected for the TI- JMP OUTPT H. J. Kuhman 59, this program will not yield the INP: IN 1 ;GET STATUS Pittsburgh PA ANI 01 MASK expected result with a seed of 0.9 JNZ INP given on pp. 108-109. Once in a while I really blow it, IN 0 I suggest that in future articles CMA and this was one of those occa- on TI calculator programs, you ANI 7FH sions. It was simply my enthu- RET specify the calculator model for siasm for the subject, and that of which the program is intended, many readers, that made me de- Table 1. and that you provide a copy of cide to run the article. Thanks for the PC-100A program-listing the feedback; I'll try to be more printout, so that no ambiguity in careful. —John. interpretation is possible. machine code of 41,00, rather This was anticipated, since any- David P. Leising than the necessary 41,20. This thing short of enclosing your pay- Grand Rapids MI can be rectified if a space follows ment within a ton of cement is A Stimulating Response the A in the source of DW 'A'. usually insufficient to allow any It is an SR-56 program, and I It should read DW 'A '. correspondence to escape from Thank you for sending our apologize for the omission. 5. My assembler didn't like the the batch-processing syndrome. book, Stimulating Simulations, —John. instructions given it on addresses Therefore, Consumer Computer, to a reviewer who took the time to 210-212, it would rather have Inc., was overcome in its first read the text and actually put the seen SPACE: DB 20H,20H,20H. skirmish. No billing problem was program listings into the comput- 6. Similarly, address 213 as- corrected and a fee for the ser- Defective Formula er. Robert Soltysik's statements sembles to 0A0D, rather than the vices of Consumer Computer was (Kilobaud, April 1978, p. 13), al- necessary 0D0A. A source state- certainly not collected from the though not in complete agree- In the December 1977 Kilo- ment fix of DW 0A0DH will firm issuing the improper billings. ment with mine, were obviously baud, p. 24, one of your cor- straighten that out. Round two saw "yours truly" based on careful examination of respondents suggests the formula 7. As is necessary for most ma- taking American Express to New the book. His objectivity was cer- arc sin X = ATN(X/SQR chines, 1 had to rewrite the I/O York City's Small Claims Court. tainly a relief after I read a review (1-X**2)). This formula has the routines to conform with the Intel Running true to form, American of The Devil's Dungeon in the defect that when X = 1 or -1, a TTY interface card. For those of Express failed to answer the sum- March issue of Interface Age. division by zero is required. Also, you who have an Intellec 8/Mod mons to appear in court. This The Interface Age reviewer made when X is close to 1 or -1, ac- 80, the routines are shown in caused a judgment to be entered statements that indicated he had curacy is impaired through the Table 1. against American Express. The not entered the program in the loss of significant digits in form- This program is an asset to any arbitrator, who calculated the computer or even read the sce- ing 1-X1. hobbyist or programmer who amount of the judgment award, nario carefully. Instead, he vent- programs in 8080 assembly allowed an added $70 for ex- I suggest instead the formula ed his hatred for computer language. penses (largely Consumer Com- arc sin X = 2 • ATN(X/(1 + games, The Wumpus in particu- puter, Inc). Thus, Consumer SQR(1-X*X))). This formula is lar, on my poor little book, which Rick Beutnagel theoretically exact and preserves Hilton NY Computer, Inc., won an over- many readers and publishers have whelming victory by correcting the number of significant digits. found delightful. Thank you for my billing difficulties and collect- Also, X*X usually executes faster employing intelligent and consci- ing $70 from "Goliath," rather and more accurately than X**2. entious reviewers. The next time I Score 2— than the $25 fee it was originally The formula arc cos X = -arc want to communicate with the For Consumer Computer hoping to charge American Ex- sin X + (0.5 * it) holds in all West Coast, it will be through press for its services. cases, giving the angle between 0 your magazine. and it radians. In the March 1978 issue of Beware Master Charge, Visa, There was one problem with Kilobaud, a short article entitled Carte Blanche, et al—Consumer Charles A. McCarthy the review, however. My address "Consumer Computer, Inc.," Computer is ready to pounce St. Paul MN and the price of the book were appeared. This work describes wherever and whenever you make omitted. Stimulating Simulations software, written in North Star the slightest error by slipping a sells for $5 and can be purchased BASIC, capable of generating loose bit in your overgrown com- Meatless Article from Engel Enterprises, PO Box replies to billing form letters pro- puter frame. 16612-K, Tampa FL 33687. duced by large computers em- Joseph Roehrig The quality of articles in Kilo- Jane E. Engel ployed by giant corporations. Middle Village NY baud has always ranged from Publisher The article stated that this soft- fantastic to restating the obvious, ware is running on an Imsai 8080 and 1 have no complaints about and is being utilized to do battle this. However, in the April issue, "Tiger Trouble" Trouble 6800 Owners: Look Out! with one of the largest credit-card on pages 116, 117, I found the companies in business. biggest waste of paper I have ever Well, the results are in, and This letter refers to the article seen in your magazine. Jim Huff- I recently purchased Practical Consumer Computer, Inc., lost a "Tiger Trouble" (p. 106) in the man's "Finally: 8080 Meets the Microcomputer Programming: few battles but won the war. The March 1978 issue. Although the Fairchild Video Game" was a The M6800 by W. J. Weller, form letters generated by the calculator used was not identi- farce. It was nothing more than Northern Technology Books, microprocessor were completely fied, I have assumed that it is two pages of: . . . 9023, a num- 1977, $21.95. I am very disap- ignored by American Express and either an SR-52, TI-58 or TI-59. ber not yet given in any data pointed with the book and hope its overgrown computer system. The program as printed on p. books . . . will release data in a you will not promote it. Here are ten in North Star BASIC, since I my complaints: reach into and pull out articles on Demystifying the April no longer had Altair equipment. 1. There are no equipment a particular computer. We pub- Tic-Tac-Toe Program block diagrams, such as to de- lish articles that have been writ- This changed the article dras- scribe programming models of ten. If you, or any other 1802 tically. the MPU, PIA or ACIA. This is a owner, would like to see more I'm sorry about the errors in 5. We decided to go with cor- particular disadvantage when try- material on the 1802, then go the Tic-Tac-Toe article appearing rected versions of the typed list- ing to describe the behavior of the directly to your typewriter . . . in the April Kilobaud. Basically ing so as not to change the article. peripheral chips. do not pass GO ... but perhaps what happened is: 6. In the confusion, the neces- 2. There is no description of the you will collect that $200! You 're 1. I wrote the article before I sary corrections were not incor- hardware interrupt signals, even right about the 1802 gaining in had a printer and attempted to porated and one additional type- though there is a chapter on inter- popularity and I'll be happy to type the listings from my video. setting error was added. rupts. Also, this chapter contains see more written about it.—John. 2. Kilobaud returned a draft of I have no Altair BASIC, so I inaccurate or misleading state- the article. This draft contained cannot supply a listing. The cor- ments. numerous errors in the listing (my rections are shown in Fig. 1. 3. The book departs from Other answers to questions are Computer-Portraits Franchise fault) and pages of program list- Motorola assembly language ing were out of order (Kilobaud shown in Fig. 2. with several pseudo-ops, with placed page 10 in front of 9). In addition to the correc- some of the number base conven- I read with interest your letter 3. The new proof was sent to tions, I have attached a North tions and with indexed address and reply in the letters column of me and we still had problems. Star listing of a similar game notation. December 1977 on the subject of John Craig and I decided to hold (see below). 4. The book uses no flowcharts computer portraits. We are pres- publication of the article until I Thanks for your under- to outline or generalize programs. ently setting up a franchise orga- obtained a computer-generated standing. 5. The chapter on floating- nization that will allow just about listing. Joseph J. Roehrig point arithmetic could have been anyone to go into computer por- 4.1 sent computer listings writ- Middle Village NY written for any computer or traits. The franchise fee will be, microprocessor. It had no real not $7000 to $10,000, but only how-to-do-it information and did $5000 for everything, including not even mention any actual the computer, line printer, TV 30 FORA = 1T03:A1 = A'10:FC)RA2 = 1TOIO:FORA3 =ffT03 floating formats. camera, video monitor and soft- 105 IFA>640R1>ATHENPR1NT'1LLEGAL MOVE'iGOTCWO I feel that the book is not well ware. We feel this system will 200 M3 = -9 organized, but this, I know, is a have more capabilities than any 280 IF5>A6THENM2 = M2 +• A6tA6:GOT0300 subjective matter. other system available, and we 320 IFM2>M3THENM3 = M2:M4 = A Who am I? MSEE with ten are dedicated to continually 392 A1 = INT((M4-1)/16) + 1:A2 = M4-((A1-1)*16) 1000 PRINT'POSITIONS ARE';:FORA =0TO3:FORAl = 1T013STEP4:A2 = 20 + (A1*4) years' experience on minis and in- upgrading all units in the Field so it will remain so. Anyone desiring terfacing. Owner of Altair 680 Fig. 1. and MEK6800D2 kit. Instructor more information is invited to (moonlight job) on 6800 system write me at Tri Mark Engineer- at Midwest College of Engineer- ing, 12402 W. Kingsgate, Knox- NEXTA1.A Altair BASIC lets you end multi for loops with ing. 31 years as W9CUP. ville TN 37922. NEXT by listing the variable of the loops to be ended I do like Barden's book (re- Marshall Dudley SS(A) Altair BASIC treats string variables similar to viewed in January 1978 Kilo- President numeric values. Thus : baud) and the Scelbi 6800 Soft- Altair SJ(1) could mean -UU' and SS(2) would be 'CO ware Gourmet Guide and Cook- Sounds like a good topic for an North Star SS(I.2) = 'UU' and SJ(3.4) = 'CC' book. article, Marshall.—John. Hg. 2. Terry A. Jackson Lombard IL
10 DIMS(64),U<3»76>,S$<64> ,V<76> 11 DIMC9(64. 8 > More Articles on the 1802? 20 FORA-1 TO10\FORAl-OTO3\REAElU < A1 * A ) \NEXTA1\NEXTA 30 F0RA=lTO3\Al=A*10\FORA2=lT01O\FORA3=OTG3 40 U ISH. O) • •H JQ f/ / CO I I a) o IfiI ">O y- h ^ ir*i "oO .oQ -""IT i Emerson Brooks case letters, and automatic 517 Melody Lane Richardson TX 75081 page formatting. This was to be done by means of non- printing control characters, as will be explained in part two. The Mechanical Marvel The Selectric typewriter is a mechanical marvel or night- mare, depending on whether Taming the I/O it is working right or you are trying to understand how it works and repair and adjust it. The basic typewriter is Selectric (Part 1) entirely mechanical except for the electric motor and switch. The characters are It's time to get that I/O Selectric you've been using as a typewriter selected by tilting and and interface it to your home computer rotating the ball (typing ele- ment) to get the proper char- acter in position, and then striking the ribbon and paper It makes beautiful copy. Now with it. The sequence of I can type assembly listings, events goes something like use my computer as a text this: The motor drives a editor and type out letters or pulley through a toothed articles like this one. belt, which drives the opera- Last January I gave a talk tional shaft on the right side about my Selectric Interface of the machine. A series of at a meeting of the Computer clutches and cams on this Hobbyist Group of North shaft performs the carrier Texas, which was received return, line feed, tab, space, with a lot of interest. Editor back space and shift func- John Craig heard about it and tions (more about this later). suggested an article for Kilo- The pulley also drives the baud. So, I am now sitting at cycle shaft on the left my TVT typing words into through a clutch on the RAM and printing them out pulley. The cycle shaft drives on the Selectric. the filter shaft and print shaft through gears and does the Photo 1. The IBM Model 731 Selectric as used in the 1014 Remote The Selectric Interface is print function. Inquiry Unit. The case has an extension on the bottom to house the presented in two parts: Part solenoids, which permit remote operation of the typewriter. one describes the hardware, When you press a key, an and part two will cover the interposer is pushed down so software. that it trips the cycle clutch IBM is no longer making the I/O Selectric and as more and more IBM to start the print mechanism. systems are upgraded there will be an increasing number of these units More Than a Printer It is also positioned so that a coming onto the surplus market. I've seen several articles on interfacing blade on the filter shaft the Selectric, but / believe this is one of the best. It's very likely the I/O The 1014 Remote Inquiry Selectric will become more and more popular as a hard copy device for Terminal is of early 1960 strikes it and pushes it for- hobby systems due to its rugged construction Ino comparison with an vintage. The Selectric is ward. The interposers, a dif- office Selectric) and the cost IS700 to $950). The Model 731, which mounted on a heavy steel ferent one for each key, have Emerson's article is based on, is mechanically the same as the Model desk, which is full of power teeth that push against six 735. — John. supply, relays and diodes. I selector bails. The selector didn't have room for the desk bails in turn push latches so I removed the Selectric from under a latch bail that is and discarded the relay en- being pushed down by cams ast spring I was just get- work, and a friend offered me coder and decoder circuitry. on the cycle shaft. If the Lting started in the home a surplus IBM 1014 Remote That meant that I had to latches are left hooked, the computer hobby. I had as- Inquiry Terminal, which con- provide everything between latch bail will operate a sembled my SWTPC M-6800 tained an IBM Selectric the 6800 output and the sole- mechanical differential kit and was making my first Model 731 typewriter. So, noids in the Selectric. I also mechanism that moves attempt at programming here was my hard copy out- decided to give my hard copy pulleys to pull on the steel when it became obvious that put device; all that I had to printer some extra smarts by tapes. These tapes are any serious work would re- do was interface it with my arranging for computer con- wrapped around two drums quire a hard copy output. As computer. trol of typewriter on/off, which rotate and tilt the type is the case with all computer Well, it's all working now, single or double spacing, all element. If the six latches are hobbyists, I talked about it at and I am very happy with it. capitals or upper and lower- hooked, they produce rota- tion of one unit (R1), two You don't have to under- units (R2) and two units stand all this to get the point (R2A) to the right, and tilt of — to control the Selectric by one (T1) and two (T2) units. the computer, all you have to The five-unit rotation (R5) is do is provide solenoids to an exception. Latching pre- control the latches. Similar vents five units of rotation to solenoids can control the the left. Combinations of clutches for space, back these latches can then print space, carrier return, line any of the 44 characters on feed, tab and shift. My Selec- half of the type element (four tric had all of the solenoids rows with 11 characters per except for the shift. If yours row). The shift operation doesn't, and you have a little turns the ball 180 degrees so mechanical ability, you that the characters on the should be able to add sole- other half of the ball can be noids made from old relays. printed. Before you start, be sure to Though all this may sound get a copy of the service like a Rube Goldberg manual for your typewriter. Photo 2. The type element is visible on the carrier. The carrier rides on the print shaft, which is driven by gears on the left side. The 11-inch machine, it is really a care- Manuals and repair parts can platen has pins for paper drive. fully designed device, with be obtained through your interlocks to prevent im- local IBM office or through proper operation if the oper- an IBM Parts Distribution ator presses two keys Et once, Center, which, in major or if there are other timing centers like Dallas, provide problems. Long trouble-free 24-hour service at fair prices. service is obtained through wear-adjusting compensation. How Many Control Lines? You have to take your hat off There are 13 Selectric to the Selectric designers. functions, so it would seem SHIFT • 48V MJE340 SOLENOID _J o o jT —•yF, , , jjO!!iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiih.i..in^. ©O _JAB_ Photo 3. The belt drive is in the center of the photo. To the left of the drive pulley are the cycle dutch, five-unit cam, selector cam and reset cam on the cycle shaft. To the right is the operation shaft with the 3R shock release dutch, carrier return dutch and pinion, tab governor and o pinion, space and back space dutch and cam, and carrier return and index clutch and cam. The shift mechanism is on the right end of the operation shaft. _CR_ o SAME CIRCUIT TO ' DRIVE OTHER that 13 control circuits from circuit diagram (Fig. 1), the SOLENOIDS the computer would be re- CK line that is always on quired to control the type- when a character is being writer. However, when the typed is used to control the £ typewriter is typing a char- electronic equivalent of a six- =D— acter only the seven type pole double-throw switch. g element control functions, When CK is on, the type R1, R2, R2A, R5, T1, T2 and element control functions are CK (trip the cycle clutch), connected to the computer. and SH (shift) may be re- When CK is off, the non- x> quired at the same time. The printing functions are con- next five functions, SP nected. (space), BS (back space), CR The shift function must (carrier return), IND (index = "iCHCH" not change during a character IBM for line feed) and TAB typing operation and is pro- (tabulate), do not need any vided a control line of its own of the type element control so that it may be controlled functions. This allows a line- separately from the other saving multiplexing scheme to functions. Fig. 7. Interface circuit diagram. be used. As shown in the With this interface cir- cuitry, all of the functions of cause down shift. Then used surplus Motorola two one-shots with about 20 the typewriter can be con- binary 00000001 or hex 01 MJE340 Darlington tran- milliseconds on time to drive trolled. For example, to do a would cause "-" to be typed. sistors, one for each solenoid. the two shift solenoids. The line feed, binary 00100000 or Following this pattern, you All of the solenoids in the shift line switching on should hex 20 should be the output can make up a table of type- typewriter were disconnected then trigger the up-shift one- to the typewriter. To type a writer codes for all of the from the original circuit, and shot and when the shift line capital A requires shift up, characters on the type ele- reconnected with common switches off the down-shift tilt two units and rotate left ment just by noting what leads to the +56 V supply. one-shot should be triggered. two units. The typewriter shift, tilt and rotation is The transistor collector was The 5 V power supply is a then requires binary needed. connected to the other 1 Amp regulated supply I got 10100111 or hex A7. If the Turning on the typewriter terminal of the appropriate in a kit. The 56 V supply was typewriter was in a down- and the power supplies is a solenoid, with a 1N4007 made from a surplus 40 V 1 shift condition, a binary little different because the diode to protect the tran- Amp transformer, bridge 1 10000000 or hex 80 would switching circuit can't work sistor from the solenoid Amp rectifiers, a surplus be required to shift up before with the power supply off. fly-back voltage. (A similar 1000 uF 100 V filter capac- sending the typewriter the A7 To get around this I used the fly-back protection diode is itor, but no regulator. to type A. As soon as the CA2 handshake control line provided with the power re- The interface circuitry was typewriter has started the to directly operate a relay lay.) The transistors are built on Vector .1 inch per- type operation, the output (Radio Shack #275-004). The driven directly from the TTL forated circuit board and should be changed to 80 to power relay applies the 115 V ICs with a series 1k Ohm with a Vector wiring pencil hold the up-shift condition ac to the typewriter motor, resistor to limit current. The and solder-through wire. All but allow resetting of the the 5 V and 56 V power power supply is 56 V to allow of the circuitry and power latches to prevent typing a supplies. for voltage drop in the tran- supplies were mounted on a string of AAAAAAAA. Now, The solenoids in the type- sistors and supply 48 V to the plastic cradle in the space if a hyphen is to be typed, writer require about 48 V dc solenoids. under the typewriter shift down, tilt three and five at about 100 mA to operate The solenoids in the type- mechanism, as shown in the right rotation are required. reliably. This is too much for writer operate trip-type photo. The third transformer Before typing, 00 would be the usual TTL device, so a mechanisms — that is, when a was required because my sent to the typewriter to driver circuit is required. I solenoid is energized it trips a typewriter motor turned out latch, and then even if the to be a 208 V motor. I found solenoid is turned off, the a 75 V 1 Amp surplus trans- function is still enabled. To former, which I connected up prevent the typewriter's being to boost the line voltage to left in some unknown char- 190 V, and that was high acter condition, the CA2 line enough to make the motor interlocks the CK and SH start and run properly. functions so that none of the type element control func- Timing By Software tions can be tripped while the The Selectric had many typewriter is off. contacts on it for use as My Selectric had no shift character input to the com- mechanism when I got it. puter and as feedback con- Since a shift is necessary to tacts for timing purposes. I get all the desired characters, had decided not to use the I had to add it to the Selectric keyboard for two machine. I bought all the reasons. First, I felt that the necessary parts except the TVT terminal made a more solenoids from the IBM Parts convenient input device, and Center for about S20 and second, the type element used an old relay to operate with the characters that I the shift clutch mechanism. wanted bore no relation to With this arrangement, the keyboard arrangement. My shift circuit must be 731 Selectric has a non- energized whenever shift-up is standard keyboard. Therefore required. The standard IBM I removed the character input shift circuit uses two latching contacts to get them out of solenoids with one being the way and make servicing energized to trip the shift-up easier. Photo 4. A view of the underside shows the seven selector solenoids at condition and the other to I originally thought of the left rear. These push the latches from under the latch bail for trip the shift-down condition. character selection. The vertical bars at the front under the keyboard using the feedback contacts If your Selectric has the are the interposers. and the horizontal bars are the selector bails in a handshaking mode ol mentioned in the text. On the right side are the five operation solenoids standard shift solenoids you operation with the computer. for space, carrier return, etc. Below these is the relay / added to trip the will want to change the cir- But then I considered the shift mechanism. The solenoid near the middle is a keyboard lock-out cuit shown by providing an- need to maintain contacts, which / have not used. The typewriter mechanism sits in a plastic other transistor to operate cradle, which serves as a mounting for the parts for the electrical the added interface circuitry interface. the second shift solenoid and required and the possibility SELECTRIC HOWE TYPEWRITER INTER- t FACE "v D L U. L * ' M, J Jl Fig. 2. System block diagram. of the computer's hanging up with a difference. The cycle waiting for a missing contact and shift clutches are wrap-up closure because of grease, dirt spring clutches, and take hold > £ or other problems. Open loop almost instantly. The space, # software timing by the com- back space, carrier return and Photo 5. On the left is the 56 V power supply to operate the solenoids. The other large transformer is to adapt the 208 V motor to the 117 V puter looked pretty good, line feed clutches are power. The circuit board with the transistors, diodes, and the ICs that and as it has turned out it was sprocket-and-dog clutches, control the solenoids are mounted on the bottom of the cradle beneath a trouble-free choice. the sprocket having nine the power relay. The 5 V power supply is at the rear. In order to do the soft- teeth. This means that there ware timing, you have to is a 1/9 operational shaft know accurately the time re- revolution time uncertainty quired for each function, or or 1 5 milliseconds in the time allow extra time for the un- for these functions. For this certainty and thus slow down reason, the space and back the output rate. space functions are allowed The basic timing comes 81 milliseconds. from the rotation of the oper- Line feed requires a full ational shaft, which turns at turn of the operational shaft 7Vs revolutions per second. and gives a time of 148 milli- When the cycle clutch is en- seconds when the clutch un- gaged to type a character it certainty is added. The time turns at the same speed as the required for carrier return is operational shaft. The cycle dependent upon how far the shaft cams are double lobed, carrier has to travel. I allowed and so type a character in 525 milliseconds for the half a revolution. This means carrier return — enough for that the basic maximum an 80-character line. typing speed is 15 characters Photo 6. The shift dutch, cam, and solenoid had to be added to my per second (or 67 milli- Where Do You Plug It In? machine. The shift cam pushes out the arm with the pulley on the upper end, which pulls the rotate tape to turn the type element 180 seconds per character), which There are ten wires going degrees. is pretty respectable. The to the typewriter — eight for pull-in time for the solenoids typing functions, one for the is appreciable, about ten power relay and a common tem block diagram (Fig. 2) when a character has been milliseconds. However, all of ground. These connect to an shows how this was done. sent to the TVT and the the typewriter functions are MC6820 peripheral interface Two NAND gates (7400) ACIA has received it, the initiated by solenoids; so this adapter (PIA) in the com- were connected in cascade, ACIA interrupts the com- common time doesn't have to puter: the eight control lines with the ECHO switch tied to puter through the nonmask- be counted, as far as the to the data output PIA one of the inputs of the able interrupt line (NMI). The software timing is concerned, terminals and the power relay second gate. The two inputs computer takes the character because the pull-in time can line to the CA2 terminal. of the first gate connect to from the ACIA receive overlap the completion of an- Then the computer only has the serial data line from the buffer, converts it to the other function. to put the proper outputs to computer to the TVT. When proper control byte for the Shift up or shift down the PIA to control the type- the ECHO switch is on, the typewriter and puts the byte must be done as a separate writer. output of the second gate out to the PIA. After the function, and not while I thought the easiest way echos the serial data going to proper time delay for type- typing a character. A half to interface the typewriter to the TVT. When that switch is writer operation, the com- revolution of the operational the program requiring hard off, the output is high or puter is returned to the main shaft is required for either copy output would be to mark. The output is con- program. shift up or shift down (1/15 have the typewriter echo nected to the serial input The software that does all second or 67 milliseconds). what is being written on the terminal of an MC6850 asyn- of this and controls the Space and back space are TVT screen, thus requiring chronous communications Selectric typewriter will be also done in half a revolution minimum modification of interface adapter (ACIA). described in part two of this of the operational shaft, but existing programs. The sys- With the echo switch on. article. • Norman E. Thagard, M.D. 669 Edmonds Dr. James Island SC 29412 Home-Brew Z-80 System (Part 1) If you want to build your own system from scratch, just follow these instructions. Due to the informal nature of Kilobaud, we don't normally provide used but would require the use bringing BUSAK low. On the an author's profile with each article... or even discuss an of an external refresh circuit. CPU card, this signal is inverted author's background. With Norm Thagard, I'm going to make an My home-brew TVT is entirely to become the S-100 signal exception. Norm was one of 8079 applicants for America's next stand-alone with off-line PHLDA (DMAG or DMA grant). generation of astronauts ... the NASA Mission Specialists who capability; so I did not care that If the front panel has re- will be going into orbit aboard the Space Shuttle. When the com- DMA by other devices, such as quested the DMA, the address petition got narrowed down to 208 aspirants Norm called me on DMA requiring TVTs, would not bus is controlled by 74193 the phone and told me he wanted to use the fact that he had built a be possible during front-panel counters through Tri-state buf- home-brew computer system, and published an article on it, as ad- operation. This would not be a fers ICs 15 to 17. At the same ditional leverage with NASA. Maybe it helped, because he was one time, control of the data-out of the 35 selected for the mission-specialist slots. Congratula- serious disadvantage consider- tions ... and the very best to you, Norm.—John. ing the normal reason for using bus is made possible should a the front panel, that is, for front-panel write operation en- small program development sue. Finally, the CPU card Tri- he availability of several especially wanted from my and/or bootstrapping tape pro- state buffers are disabled by low-cost S-100-compatible system: First, compatibility T grams into memory. With data the active low signals CC Z-80 CPU boards, the high cost with the many commercial latches and additional logic, it DSBl, DO DSBL, SDSBL and (for a medical student) of com- S-100 peripherals available. would be possible to restore ADDRDSB. mercial S-100 systems and a Since I was using the commer- full DMA operation. Single-step ICs 19 to 21 are depicted as burning desire to have a per- cial CPU card, this aim was operation is a nice feature per- 74LS368 Tri-state buffers, but sonal Z-80 system prompted easily met—I only had to avoid mitting you to go through a pro- could be 8T98 or 8098 types as me to design and construct a compromising what was gram op code by op code. This direct replacements. However, front panel that provides the already there. Second, an is very handy for debugging the 8T98 will draw more current logic to use the commercial expandable system—up to 64K software and, fortunately, very and the 8098 will represent a CPU boards in an otherwise of memory and I/O ports galore. easily implemented. larger load to the bus. Alter- home-brew system. In my case, Basically, this meant the use of natively, 7404, 7405 or 7406 the S.D. Sales Z-80 CPU card Tri-state buffers in an expand- Theory of Operation types could be used with a dif- was available locally and was able bus configuration. ferent pin-out and higher bus the starting point for the DMA is possible with a Tri- Also, I wanted to use, loading. The 74LS04 cannot be design. state bus system and some wherever possible, standard means to suspend MPU opera- used because it will sink only Lacking software experience TTL chips that I had pulled off tion. On the Z-80 chip is a pin eight mA in output low state. A with the Z-80, I needed a old boards at an average cost labeled BUSRQ. It might better bit that is at logic one will software-independent unit. In- of three or four cents. I wanted be named DMARQ because cause the indicator LEDs to be deed, one of my major goals to avoid, at all costs, the use of bringing this pin low forces the forward biased and the 10 or 12 was to have a system with special devices. However, in MPU to set its address, data mA should give adequate light which I could develop software. the interest of reducing bus and Tri-state output control output. The result was a manual front loading and parts counts, I was signals to the third, or high- To load the address, set the panel permitting direct access willing to use some low-power impedance state, thereby 16 sense switches, SS0 to to memory for both read and Schottky packages. facilitating DMA operation. In SS15, to the desired location write operations. our case, switch S3 (Fig. 1) is I was also willing to sacrifice and toggle the LOAD ADDRESS Armed with the Z-80 debounced and forces PHOLD the dynamic refresh capability switch S7. This brings the load technical manual and the low, which is applied through a of the Z-80 to take advantage of pin on the four counters, IC11 schematic of the S.D. Sales Tri-state buffer at the CPU card a straightforward method of to 14, low, which latches the ad- CPU card, I began the design. to pin 25 of the Z-80 MPU (Fig. front-panel operation. This dress. Then this address ap- The outgrowth of the effort is 2). As soon as the current method is called direct memory pears at the Q outputs and at depicted in this article. machine cycle is ended, the access (DMA) and is readily im- the address bus via the buffers. MPU grants the request and Design Considerations plemented with the Z-80 MPU. To increment an address acknowledges the grant by already loaded, toggle the EX- There were several things I Dynamic memory could still be its socket. Bend pin 11 outward carefully and replace the IC (be careful that pin 11 remains out- side the socket). If other Z-80 circuit boards output the machine cycle state Ml on bus line D05 (S-100 bus line 39) dur- ing PSYNC, it may be necessary to disable this feature in a similar manner. Otherwise, attempts to load memory from the front panel may result in errors in bit 5 as two Tri-state devices fight each other for control of that bit. Construction Because of a fortuitous cir- cumstance (low price and availability), my front panel was constructed on a large pro- totyping board with excellent ground and power buses. Either this sort of board or an S-100 prototyping board is recom- mended. If the S-100 board is used, you can simply take a standard aluminum chassis of appropriate size, mount the desired number of S-100 edge connectors on top of the chassis, hand-wire the connec- tors together and place the front-panel board in the for- wardmost edge connector. (The Results of my efforts. pin connections on the diagrams reflect S-100 bus signals.) AMINE NEXT switch S5, which enable pulse from IC9a, the ad- switch S2. This switch is de- Is debounced and applied dress counters are incre- bounced and clocks in a logic A PC board is really not very through IC7a to pin 5 of IC11. mented automatically to ac- one to the D flip-flop IC2a. This, practical. It would be tedious to Note that the increment does cess the next sequential loca- in turn, allows PRDY to go high design and would not be suited not occur until S5 is released. tion. via IC4c and 10. PRDY commu- for the inevitable modifications This is because the 74193 The data-in bus is con- nicates with WAIT on the Z-80 that home-brew enthusiasts counts up on a zero-to-one tran- tinuously monitored by the in- MPU. As long as WAIT is held are prone to make. Wire-wrap sition, which does not occur un- verter/LED circuitry of IC6 and low, the Z-80 will continue to and wiring pencil are the two til S5 is released. 22. Here, 7404 types are used "spin its wheels" by executing techniques usually employed; I Access to the data-out bus is because there is little need to wait states. used the latter. Layout is by no through buffers IC17 and 18. reduce loading on a bus that Activating the STEPPER means critical, and I actually These buffers are activated on- usually communicates only switch allows the Z-80 to used no bypass capacitors ex- ly during a write operation. with the CPU. resume normal operation until cept for 50 uF electrolytics at After the desired address is If a program has been loaded the next instruction-fetch cycle the points where Vcc entered loaded, the data is set by sense into memory, it will execute, comes up. When this happens, the board. However, good prac- switches SSO to SS7, which do starting at location 0000,,, by the Z-80 signals the event by tice (according to Don Lan- double duty as data and low- returning the DMA switch to bringing its M1 pin low. This caster's TTL Cookbook) calls order address byte switches. RUN and then depressing the signal appears inverted as SM1 for one 0.01 to 0.1 uF ceramic With the data set, the DEPOSIT RESET switch S6. If the CON- on the S-100 bus and will trigger capacitor per four gate pack- switch S4 is activated. If DMA TINUOUS/SINGLE STEP switch the one-shot IC1. In turn, IC1 ages or per two MSI packages. has been granted to the front S1 is in CONTINUOUS mode, clears the flip-flop once again, When using a wiring pencil, it is panel, the debounced toggle the execution will continue un- bringing PRDY low and throw- a good idea to check continuity passes through IC7b to IC9a, a til a software HALT, 76,„ is en- ing the Z-80 back into neutral of each interconnection with an one-shot. The one-shot places countered or DMA is requested until the next STEPPER switch ohmmeter. the data on the data-out bus by and granted. If SINGLE STEP toggle. You may generally follow the enabling IC17 and 18 and trig- mode is selected, each op code One change should be made layout shown in the accom- gers the write pulse generator must be executed one at a time on the S.D. Sales CPU card. panying photograph or change IC9b. At the end of the data- by toggling the STEPPER IC20 should be removed from it to suit your own inclinations. A word of advice: the DEPOSIT, threes for octal. Although be phenomenal. ICs in this project are all "at the EXAMINE NEXT and STEPPER space requirements may tempt corners," as is standard with switches will be frequently you to place the sense Checkout TTL, so make sure they are con- used and should be convenient- switches as close together as Prior to applying power, use nected to the appropriate bus. ly placed. The sense switches possible without grouping your ohmmeter to ensure that With no other device in the can be grouped in fours as them, don't do it! With such an no Vcc-to-ground short exists. system, power up the front shown for hex notation or in arrangement your error rate will The supply connections to the panel. It should draw about 1 Amp at 5 V dc depending on high level. If this is the case, regulated and have on-board memory location where it can how many LEDs are illu- then it should be safe to plug in regulators. be examined. minated. With a voltmeter, the CPU and memory cards. Be You can now perform a quick 1. Set DMA switch to DMA check the enable pins of the Tri- sure to remove power before checkout and run a simple pro- mode and SINGLE STEP switch state buffers of the address inserting these cards, and bear gram at the same time. The pro- to CONTINUOUS mode. It may and data-out buses. These pins in mind that the commercial gram will add two binary num- be necessary to activate the should be in the disabled or boards require +8 V dc un- bers and store the result in a RESET switch to get a DMAG Fig. 1. Front panel. ICs The address indicators will TINUOUS mode by moving the 1 74121 show 0000,, and the data LEDs DMA switch to DMA and tog- 2 7474 will display 3E„. Activate the gling RESET. The address indi- 3, 5, 8 7402 STEPPER switch once. The ad- cator will show 0008,,, indi- 4 7437 dress will now be 02,, and data cating that program execution 6, 22 7404 will be C6„. Address 0001,, will is complete and the MPU has 7 7408 appear to have been skipped halted. Return the DMA switch 9 74123 but, in fact, will have been ac- to DMA and LOAD ADDRESS 10, 15-18 8T97 cessed and 08„ will have been 0010,,. The result, 10„, should 11-14 74193 loaded into the accumulator. once again appear on the data 19-21 74LS368 As the MPU does not enter wait LEDs. Miscellaneous states until instruction-fetch 1 circuit board of choice 7" x 12" (see text) cycles occur, it will always ap- Conclusion 1 edge connector for circuit board pear to skip certain locations. This article has described a 24 LEDs MV5054 or similar Continue toggling the STEP- simple manual front panel that 24 300 Ohm, V« W 10% resistors PER switch until the HALT in- can be combined with commer- 1 10 330 Ohm, /« W 10% resistors struction is encountered. cial S-100 Z-80 CPU boards to 18 2.2K Ohm, Va W 10% resistors 13. Now return the DMA provide a working Z-80 com- 2 10K Ohm, Vi W 5% resistors puter system. This will allow 1 20K Ohm, V< W 5% resistors switch to DMA mode and then 1 10 pF disk cap move the SINGLE STEP switch the user to bootstrap tape pro- 1 0.01 uF disk cap to CONTINUOUS. LOAD AD- grams into his machine and to 1 0.1 uF disk cap DRESS 0010,, and the result of develop simple routines. It is an the addition, 10„, should ap- excellent way to experiment Switches pear on the data LEDs. and familiarize yourself with 51, S3 SPDT toggle switches 14. DEPOSIT 00„ in location the Z-80 instruction set. It is 52, S4-7 SPDT spring-loaded toggle switches 0010,,. Try now to execute the probably the cheapest way to SS0-15 SPDT toggle switches same program in CON- assemble a working system.• Parts list. » Z-80, PIN 25 (BUSRO) from the CPU. stored in the location in 2. Set up address 0000,, on memory specified by the next sense switches SS0 to SS15 two program bytes. and load this address by tog- 8. DEPOSIT 10„. The low- PRDY [72>- ^D—>- • Z-80, PIN 24 (WAIT) gling LOAD ADDRESS. All ad- order byte of a two-byte ad- dress LEDs should extinguish. dress is specified first in a •5V +SV Remember, all Z-80 programs Z-80/8080 system. In a 6800 must begin at zero on start-up. system, the high-order byte is ET M sr • Z-80. PIN 26 (RESET ) 3. Using SS0 to SS7, set up specified first. In our case, the I data byte 3E„(001111102) and address in which the ac- enter this byte into location cumulator contents are to be Z-80, PIN 27 I Ml) 0000,, by toggling DEPOSIT. stored is XX10,„ where XX is The address LEDs should now specified in the next memory indicate 0001,,. 3E„ is the Z-80 entry. X-SEE TEXT op code for load accumulator 9. DEPOSIT 00„. The high- Z-80, PIN 91D5) -O DOS immediate, and its execution order byte of our storage ad- will cause the byte in location dress is now specified to be 0001,, to be placed in the accu- 00,,. The complete address is mulator register of the MPU. 0010,,. —<53 DO DSBL 4. DEPOSIT 08„. The ad- 10. DEPOSIT 76„. This is the dress should now read 0002,,. op code for a software HALT; 5. DEPOSIT C6„. This is the its execution will halt the MPU, Z-80. PIN 23 IBUSAKI -<£6] PHLOA op code for add accumulator causing it to execute NOPs (no immediate and will result in the ops) until interrupted or reset. addition of the byte stored in The indicated address should A the next sequential memory now be 08„. location to the contents of the 11. LOAD ADDRESS 0000,,. CC/DSBL accumulator. The result will re- The data LEDs should indicate main in the accumulator. 3E„. Using EXAMINE NEXT, Z-80. PIN 27 (Ml) -O SMI 6. DEPOSIT 08„. This toggle through the first seven number will be added to the 08„ memory locations to verify the already in the accumulator. program you have just entered. A 7. DEPOSIT 32,,. This is the 12. Place the SINGLE STEP op code for load memory imme- switch in the SINGLE STEP - the most powerful 3D software yet Bit Pad. for your 8080 and Z80 • 10 projection modes. 500 lines/second • Interlaces to any S100 display device The new, • Uses 8K memory • Only $30 tor Tarbell tape and documentation (MATROX interface program included.) low-cost digitizer for small computer systems. Write to us lor more deleils and a complete catalog ol 8080 280 6800 and BASIC graphic systems Box 3442 Bit Pad is the newest product from Summagraphics. the leading LOGIC producer of professional digitizers. 11 has a small 11-inch active area and Culver City, CA 90230 S49 a small $555 price tag But the list of applications is as big as your imagination RO CHE Systems Better than a joystick or keyboard for entering graphic information, MULTI-CASSETTE it converts any point on a page, any vector, any distance into its digital equivalents. It's also a menu for data entry. You assign a value, or an CONTROLLER instruction to any location on the pad At the touch of a stylus, it's entered into your system. Who can use it7 Anyone from the educator and the engineer to the hobbyist and the computer games enthusiast. The data structure is ^ Mil-cram CMTMtUI byte oriented for easy compatibility with small computers, so you can add a power supply, stand-alone display, cross-hair cursor and many Read and write records from and to up other options. to 4 cassette recorders with one Tarbell $1,000.00 creativity prize. You can also add $1,000.00 to your Cassette Interface. bank account as a reward for your inventiveness. Just write an article Included software handles Assembly on an original Bit Pad application and submit it to any national Language and BASIC. small-computer periodical. If the editors publish it - and the decision Much more software available. Find out by writing for our free brochure. is solely theirs - Summagraphics will pay you $1,000.00 Contact Ask about our complete line of data Summagraphics for rules concerning this offer. processing supplies. Distributed by: ELLIAM ASSOCIATES 24000 Bessemer Street Woodland Hills, CA 91367 NOW HEAR THIS ! ! ! rHEUf X DISPLAYS ARE HERE! • 4 bits in dispays 9 through F • Built in latch and leading zero blanking • Use 6 modules to display hex address and data • Connect 2 modules to an output port to display registers, data, etc. • End confusing strings of discrete LEDs 7 seg. 1/3 in. display - - - Sb 80 7 seg. Vj in. display - - - $7.50 NORTH STAR SOFTWARE • Variety package # 1 - - inventory, hex and dec. translators, memory fill, electronic Design, memory test, games, and more complete package on one double-sided diskette S20 • Additional double-sided diskettes - S5 Add SI shipping and handling for orders under S20 W\&tmmaduwhiQl MC or VISA welcome 24 hours ::f!IJEi ' corporation MIDWEST DIGITAL -UTIIITIIJ 35 Brentwood Ave . Box 781. Fairfield. CT 06430 S48 863 Wood Ave. Wichita, KS 67212 Phone (203) 384-1344 TELEX 96-4348 316-722 1711 M42 physical fitness is accom- plished using three ten- minute exercise sessions per week. During each of these sessions you monitor your pulse rate and attempt to maintain it near a predeter- mined value. Each session re- quires more work to produce the same pulse rate as your condition improves. Timing the segments in each ten-minute session and timing six seconds to obtain a A Strategy for pulse count turned out to be a pain in the neck. For ex- ample if you begin at 06.59:22 and time one Healthy Living minute, then you should stop at 07:00:22 and then begin timing the next two minute This computerized exercise/fitness program provides a systematic segment. It's now 07:02:22 and time to check pulse rate approach to getting—then staying—in shape. for six seconds while counting the beats. Then miltiply the pulse count by Afs exerciser program has laid the AI Gerbens book entitled Total Fitness in ten in order to get the rate, groundwork for some really ex- 1038 E. 6th PI. 30 Minutes A Week by and begin another two- citing possibilities. The next step Mesa AZ 85203 minute countdown at is to have an analog-to-digital Morehouse and Gross (Simon pulse counter so the computer and Schuster, NY, 1975). I 07:02:37. Let's see .. . add- can monitor the pulse continu- later purchased a copy, read ing two minutes gives ously. And, along with that, 07:04:37. . .. It's really not ecently, in the process it and began following much speech output so the computer of the advice and direction it all that complicated until you can tell you (as you exercise) if Rof surviving that ordeal try it while concentrating on the pulse rate is high or low! — known as a physical examina- contains. Very briefly, the exercises. I thought that John. tion, I was introduced to a building and/or maintaining programming our microcom- puter to assist in timing and pulse rate determination 10 INPUT"HOW MANY DATA POINTS DO YOU HAVE?",W would be an interesting ap- 20 FOR Z=1 TO W plication. Here is the result. 30 #"ENTER THE NUMBER OF BEATS FOR POINT";Z 40 INPUT X(Z) 50 #"ENTER THE VALUE OF T FOR POINT";Z 60 INPUT Y(Z) Exercise Program Functions 70 NEXT Z The program listed pro- 80 #"DATA ENTRY COMPLETE" 90 FOR Z=1 TO W vides the functions of: 100 Hl = LOG(X(Z))*LOG(Y(Z)) 110 H=H+H1 1. Reviewing the major con- 120 Jl=LOG(X(Z)) 130 J3=J3+J1 cept of utilizing pulse rate as 140 J2=LOG(Y(Z» an effectiveness indicator. 150 J4=J4+J2 160 Kl = LOG(X(Z))*LOG(X(Z)) 2. Displaying the exercise se- 170 K=K+K1 quence. 180 Ll = LOG(X(Z)) 190 L2=L2+L1 3. Calculating and displaying 200 Ml = LOG(Y(Z)) your training pulse rate based 210 M=M+M1 on your age. 220 Ql = LOG(Y(Z))*LOG( Y(Z)) 230 Q=Q+Q1 4. Displaying that segment of 240 NEXT exercise sequence to be ac- 250 J=(J3*J4)/W complished next. 260 L=(L2*L2)/W 270 B=(H-J)/(K-L) 5. Timing each segment while 280 A=EXP((MAVM(B)*(L2)/W» displaying segment elapsed 290 R2=((H-J)*(H-J))/((K-L)*(Q-(M*M/W))) 300 #"B=";B time on a video display in 310 #"A= ";A five-second increments. 320 #"CORRELATION FACTOR = ";R2 330 #"USE THE FOLLOWING EQUATION FOR LINE 308 IN THE EXERCISER PROGRAM." 6. Indicating when pulse rate 340 #"Bl=INT(EXP((LOG(":A;"/T))/((-l)*(";B;"))))" determinations should be 350 END made. Calibration routine. 7. Accepting 15 pulses that correspond to heartbeats, and acting as a frequency counter crease or decrease in the rate displayed. begins in line 290. When calculating and displaying of activity, including taking a called up the subroutine your pulse rate. break. Timing of any recom- F req u e ncy/Pulse Rate watches input port one for 8. Interpreting that pulse rate mended breaks is auto- Counter. any change from 255, which and recommending an in- matically accomplished and The pulse rate subroutine it sees if all eight lines are left RUN PRESS THE BUTTON AFTER EACH BEAT. KEEP MOVING! EXERCISER PROCEED WHEN YOU ARE READY. THIS PROGRAM PROVIDES THREE 1 FUNCTIONS RELATED TO THE FIRST LEVEL EXERCISES DESCRIBED IN [|TC.] -TOTAL FITNESS IN 30 MINUTES A WEEK-BY L.E. MOREHOUSE. THANK YOU RATE = 123 BEATS/MINUTE THE THREE FUNCTIONS ARE SEQUENCE. TIMING AND PULSE RATE SELECT ANY EXERCISE SUCH AS DETERMINATION. RUNNING IN PLACE. THE OBJECTIVE IS TO GET YOUR PULSE RATE UP TO TO CHECK PULSE RATE, FIRST 111 BEATS/MINUTE AND KEEP IT LOCATE YOUR PULSE BY PRESSING THERE FOR ABOUT FIVE MINUTES. AN INDEX FINGER AGAINST ONE BEGIN EXERCISING AND CHECK TEMPORAL ARTERY AT THE SIDE OF YOUR PULSE RATE IN ONE MINUTE YOUR FOREHEAD,(TEMPLE). START USING THE OTHER HAND SHARPLY PUSH THE BUTTON IMMEDIATELY [COUNTDOWN ONE MINUTE FIVE SECONDS AT A TIME] FOLLOWING EACH HEART BEAT. IF CORRECTLY ENTERED A SINGLE PULSE RATE CHECK AGAIN NUMBER WILL APPEAR ON THE PRESS THE BUTTON AFTER EACH SCR EEN. BEAT. KEEP MOVING! AVOID HOLDING THE BUTTON DOWN PROCEED WHEN YOU ARE READY TOO LONG. MULTIPLE ENTRIES CAN 1 RESULT 15 BEATS WILL BE ENTERED AND |TC] THEN YOUR PULSE RATE WILL BE AUTOMATICALLY DISPLAYED. THANK YOU RATE = 153 BEATS/MINUTE THE EXERCISE SEQUENCE IS AT 153 BEATS/MIN. YOU SHOULD SLOW DOWN. 1) LIMBERING UP(1 MIN) CUT YOUR EXERCISE RATE TO ABOUT 2) MUSCLE BUILDUP(4 MIN) ONE HALF OF WHAT IT HAS BEEN 3) CIRCULO-RESPIRATORY FOR THE LAST ONE MINUTE. CONDITIONING (5MINS) NOW CONTINUE EXERCISING FOR THE NEXT TWO MINUTES. THE REFERENCED TEXT SHOULD BE [COUNTDOWN TWO MINUTES FIVE SECONDS AT A TIME] READ BEFORE PROCEEDING FURTHER. TIME FOR ANOTHER PULSE RATE CHECK. WHAT IS YOUR AGE? 34 PRESS THE BUTTON AFTER EACH YOUR BEGINNING TRAINING PULSE BEAT. KEEP MOVING! RATE IS 111 BEATS PER MINUTE. PROCEED WHEN YOU ARE READY 1 BEGIN WITH ONE MINUTE OF LIM- BERING EXERCISES, SUCH AS [ETC.] 1) STRETCHING 2) TWISTING THANK YOU 3) BENDING R AT E = 130 EASY DOES IT. LIMBER UP SLOWLY. LETS CONTINUE. TWO MINUTES REMAIN IN THIS SESSION. START 5 SECONDS [COUNTDOWN TWO MINUTES FIVE SECONDS AT A TIME] 10 SECONDS THIS SEQUENCE SHOULD BE [ETC.] REPEATED THREE TIMES PER WEEK. SEE YOU IN TWO OR THREE DAYS. 60 SECONDS READY ONE MINUTE Sample run. NEXT UP, 4 MINUTES OF MUSCLE EXERCISES TO ADD MUSCLE TISSUE. DO 15 PUSH AWAYS AND THEN 15 SITBACKS IN APPROXIMATELY THE Program listing (continued on following pages). NEXT TWO MINUTES. THEN CHECK YOUR PULSE RATE. [COUNTDOWN TWO MINUTES FIVE SECONDS AT A TIME) 10 GOSUB318 12 #" EXERCISER" NOW LETS CHECK YOUR PULSE RATE. 14 #" PRESS THE BUTTON AFTER EACH 16 #"THIS PROGRAM PROVIDES THREE" BEAT. KEEP MOVING! 18 #"FUNCTIONS RELATED TO THE FIRST" PROCEED WHEN YOU ARE READY 1 20 #"LEVEL EXERCISES DESCRIBED IN" 2 22 #"-TOTAL FITNESS IN 30 MINUTES" tc] 24 #"A WEEK- BY L.E. MOREHOUSE." 26 GOSUB314:GOSUB318 4 28 #"THE THREE FUNCTIONS ARE" 32 #"SEQUENCE, TIMING AND PULSE RATE" THANK YOU 34 ^"DETERMINATION." RATE = 120 BEATS/MINUTE GOOD, WITH A PULSE RATE OF 36 GOSUB314: GOSUB318 120 38 #"TO CHECK PULSE RATE, FIRST" YOU CAN NOW REPEAT THE PUSH- 40 #"LOCATE YOUR PULSE BY PRESSING" AWAY AND SITBACK EXERCISES. 15 42 #"AN INDEX FINGER AGAINST ONE" TIMES EACH; TAKE ABOUT 2 MIN. 44 #"TEMPORAL ARTERY AT THE SIDE OF" 46 #"YOUR FOREHEAD. (TEMPLE)":GOSUB314 [COUNTDOWN TWO MINUTES FIVE SECONDS AT A TIME] 48 #"USING THE OTHER HAND, SHARPLY" 50 #"PUSH THE BUTTON IMMEDIATELY" NOW LETS CHECK THAT PULSE RATE. 52 FOLLOWING EACH HEART BEAT." 54 GOSUB314 56 #"IF CORRECTLY ENTERED A SINGLE" alone. Grounding one of To help prevent multiple 58 #"NUMBER WILL APPEAR ON THE" these lines produces an input 60 #"SCREEN.":GOSUB314 entries caused by holding the 62 #"AVOID HOLDING THE BUTTON DOWN" different from 255, and the button down for too long, 64 #"TOO LONG. MULTIPLE ENTRIES WILL" program drops into another each beat is displayed on the 66 #"RESULT.":GOSUB314 68 #"15 BEATS WILL BE ENTERED AND" loop. Vou can momentarily video screen as it is recorded. 70 #"THEN YOUR PULSE RATE WILL BE" ground one of the port one Try it a few times; it won't 72 #" AUTOMATIC ALLY DISPLAYED." input lines by using a push take long to get the hang of 74 GOSUB314:GOSUB318 76 #"THE EXERCISE SEQUENCE IS:" button attached to a ten-foot it. If you have trouble, two 78 #" 1) LIMBERING UP (1 MIN)" cord, which allows you to solutions are potentially help- 80 #" 2) MUSCLE BUILDUP (4 MINS)" move around during the pulse ful. 1. Increase the timing of 82 #" 3) CIRCULO-RESPIRATORY" 84 #" CONDITIONING (5 MINS)" rate determination. It is im- the counting loop by chang- 86 GOSUB314:GOSUB318 portant not to stand perfectly ing the software. 2. Add some 88 #"THE REFERENCED TEXT SHOULD BE" still during this process. Ac- hardware in the form of a 90 #"READ BEFORE PROCEEDING FURTHER." 92 GOSUB314:GOSUB318 cording to the book, passing nonretriggerable one-shot 94 INPUT"WHAT IS YOUR AGE? ";A out cold is a possible con- between the push button and 96 A1=INT(.6*(220-A)) sequence of remaining still the input port. 98 #"YOUR BEGINNING TRAINING PULSE" 00 #"RATE IS ";A1BEATS PER MINUTE." immediately following exer- 02 GOSUB314:GOSUB318 cise, and my computer's bag Counter Calibration 04 #"BEGIN WITH ONE MINUTE OF LIMB-" of tricks does not yet include 06 #"ERING EXERCISES; SUCH AS: Each time through the 08 #" 1-STRETCHING" administration of smelling counting loop, the variable T 10 #" 2-TWISTING" salts or respiration-assistance is incremented. Calibration 12 #" 3-BENDING" 14 #"EASY DOES IT. LIMBER UP SLOWLY." capability. Enter each heart- was not as easy as I expected, 16 GOSUB314:GOSUB318 beat as you feel it with one however, because the rela- 18 #TAB(12);"START" hand by momentarily pushing tionship between pulse rate 20 FORX=1T08:#"":NEXT 22 M=60:GOSUB264 the button with the other and T turned out to be non- 24 #TABdO);"ONE MINUTE" hand. To feel your pulse, linear. After collecting a few 26 GOSUB318 lightly press an index finger data points and cranking 28 #"NEXT UP IS 4 MINUTES OF MUSCLE" 30 #"EXERCISES TO ADD MUSCLE TISSUE." against one of your temporal them through linear and ex- 32 GOSUB314 arteries (located in the temple ponential curve fit routines, I 34 #"DO 15 PUSHAWAYS AND THEN 15" area of your head). Never 36 #"SITBACKS IN APPROXIMATELY THE" obtained a 99.8 percent fit 38 #"NEXT TWO MINUTES. THEN CHECK" press both arteries simul- using the power curve 40 #"YOUR PULSE RATE." taneously. V=AXb line fit routine on an 42 GOSUB314:GOSUB318 44 #TAB(10);"START" HP-65 programmable calcu- 46 M=120:GOSUB264 lator. Realizing a lot of 48 #"NOW LETS CHECK YOUR PULSE RATE" people don't have access to 50 GOSUB282 52 IF B1 >Al + 20 THEN #'TAKE A MINUTE BREAKBEFORE CONTINUING." this resource, I've written a 54 IF B1 >Al + 20 THEN156 ELSE164 routine in BASIC that you 56 #"KEEP MOVING AROUND DURING THE" can enter into your micro- 58 #"NEXT MINUTE TO IMPROVE BLOOD" 60 #"CIRCULATION":M=60:GOSUB264 computer for calibration of 62 G0T0168 the counting loop on your 64 #"GOOD, WITH A PULSE RATE OF" system. Here's how to use it: 66 # B1 68 #"YOU CAN NOW REPEAT THE PUSH-" 70 #"AWAY AND SITBACK EXERCISES. 15" 1. Enter the exerciser pro- 72 #"TIMES EACH; TAKE ABOUT 2 MIN." 74 GOSUB314 gram, or just the counting 76 #TAB(10):"START":M=120:GOSUB264 loop if you prefer. 78 #"NOW LETS CHECK THAT PULSE RATE." 80 GOSUB282 2. Collect three or more data 82 IfBl HERE'S LOOKING TH mo©[^3> AT YOU, KID Give your 6800 computer the gift of sight' The Micro Works Digisector* opens up a whole new world for your computer Your micro can now be a part of the action taking pictures like this one to amuse your friends watching your home while you re away helping your household robot avoid bumping into walls providing fast to slow scan conversion for you hams the applications abound The Micro Works Digisector is a completely unique device its resolution and speed are un- matched m mdusiry and the price is unbeatable anywhere The Digisector and a cheap TV camera are all you II need to see eye to eye with your 6800 Since operation is straightforward you don t have to be a software wizard to utilize the Digisector s extensive capabilities The Micro Works Digisector board provides the following exclusive features • High Resolution—a 256 x 256 picture element scan • Precision —64 levels of grey scale • Speed—Conversion times as low as 3 microseconds per pixel • Versatility—Accepts either interlaced (NTSC) or non-interlaced (Industrial) video input • Compactness-Utilizes 1 I/O slot in your SWTPC 6800 or equivalent • Economy—The Digisector is a professional tool priced for the hobbyist The Digisector (DS-68) like all Micro Works products comes fully assembled, tesied and burned m Only the highest quality components are used and the boards are double sided with plated through holes, solder mask and silkscreen All software is fully source listed and commented The Micro Works is proud to add the DS-68 to its line of quality computer acces- sories for the hobbyist Prlc* 169.95 The Micro Works 6800 series of computer accessories also includes U2708 EPROM Software 29 95 PSB-08 PROM System Board 119 95 Casette tape 9 95 regulated + 1 2 volts 124 95 UIO Universal I /0 Board 24 95 B-08 2708 EPROM Programmer 99 95 X-50 Extender Board 29 95 regulated +12 volts 104 95 X-30 Extender Board 22 95 Visa and Master Charge Accepted P.O.BOX11ia DEL MAR, CA. B2Q14 714-756*2887 M31 John Craig A Tour of the Faire (Part 1) Kilobaud's editor, John Craig, takes a look at some of the people and products that made up the San Jose show. he Second West Coast TComputer Faire. What a show! I always enjoy getting out for a good convention, and this one was no exception. It occurred to me that you folks who couldn't make it would also like a peek at what the show had to offer. Therefore, I took my camera along ... and shot pictures like crazy! I sin- cerely hope you find it as inter- esting and entertaining as I did. As a matter of fact, I'd appreci- ate any feedback on how you feel about the effort... I was a little concerned with the length. If you're looking for software OK, TRS-80 owners, here it is: for home or small business, the first computer cassette Bob Lentz, the president of Micro Works, is as pleased with the you'll find it here. If you're look- "magazine." CLOAD Magazine arrives by first-class mail each computer portrait system his company has developed as the ing for the latest in mass stor- month on a C-30 cassette... gentleman on the left who just had his picture taken. (PO Box 1110, age, you'll find that also. Ter- for $24 a year. Should be in- Del Mar CA 92014.) minals? You bet. New, low-cost teresting! PO Box 1267, Goleta systems—one or two. Boards CA 93017. and components ... all over the place! Finally—some of those miscellaneous pieces of hardware you've been hoping someone would develop for SD COMPUTER PRODUCTS your system. What the heck- mention that you saw it in Kilo- baud when you drop a line to these companies, OK? Not all is well in "photogra- phy land," I'm afraid. I shot seven rolls of film at the Faire. You're going to be seeing the results of six rolls ... and I'm going to be looking for a new film processor! There are quite a few companies, large and small, who didn't make it into this write-up because of that goof—and I'm truly sorry. I keep hearing more and more good things about Come along with me and I'll the service and products from S.D. Sales ... and give you a grand tour of the Sec- they sure were doing a brisk business at the ond West Coast Computer Kinda show-offish, don't you think? Although it Faire. Bet they'll send you their catalog if you Faire ... and, above all, enjoy sure did the trick when it came to attracting write for it... or, better yet, just check their ads yourself .'• crowds! in Kilobaud. Is it Dynabyte ... or dynamite? Let me tell you, these folks have some exciting things going! On the left we have Mike Watts, president of Dynabyte, standing in front of their Z-80 based dual minifloppy system ... and their new double-sided, double-density Shugart floppy system. They have a rather unique dedicated-controller board (shown in the middle photo), which uses BASIC, which is why it's called a BASIC Controller. They were using the controller to run the two robots shown in the right photo, and they sure were a hit. (I think it was the robots that attracted the crowds . . . but it could have just as easily been Pam Farnsworth, the young lady minding the cables and the booth.) They have several other interesting products you might want to check into . . . drop 'em a line: 4020 Fabian Way, Palo Alto CA 94303. r,. .. . % vO Hey, there he is. The handsome and debonair Dr. Lloyd Rice, What can I say? That staid, conservative gentleman on the left is creator of famous Computalker Voice Synthesizer. If you're in the the one and only Bill Godbout! (The mood of revelry was probably market, give this one a listen before you buy. Computalker Con- due to the tremendous success of his Econoram memory boards sultants, PO Box 1951, Dept. K, Santa Monica CA 90406. ... and all the other items in his catalog!) The smiling face in the center belongs to none other than Carl Warren, the Senior Editor of Interface Age. The gentleman on the right? That's the real George Morrow. (Somebody who looks like George posed for the ad on page 128 of the April Kilobaud, but I know it wasn't really him be- cause George always wears tennis shoes—and you'd never catch him with a tie on!) Godbout Electronics, Box 2355, Oakland Airport CA 94614. COMPUTER PRODUCTS 5351 W 144TH LAWNDALE CALIF 90260 I pwin'?'lOft. I One of the busiest booths at the Faire had to be Jade Computer Products! The man behind all the action is Don Smith (shown in the center photo with his better half, Joanne). One of the latest products to be added to their line is the REX personal computer shown in the left photo. Don's "adopted son," Heath Kline, president of Priority One Electronics (10031 Woodley Ave., Sepulveda CA 91343), was sharing the booth—and showing off his MiniScope (and many other items). You cannot believe the incredible line of computer systems, components and peripherals Jade is carrying these days. Their spring catalog will make you drool! 5351 West 144th St., Lawndale CA 90260. Tandy was there in force . . . with many new goodies for the TRS-80. Don French (merchandising mgr. for Tandy Computers) is behind the TRS-80 on the left. His head is directly above their new elec- trostatic screen printer, which sells for $599 ... and spews out printed copy at 2200 characters per second! They also had their new mini floppies and business systems line printer up and going (right photo). Be sure to send off for their new 1978 catalog . . . it looks like they're carrying every brand on the block! 1500 One Tandy Center, Ft. Worth TX 76102. Hobby®' Computer Would you buy a reconditioned Diablo ($1995) or QUME-based terminal ($2495) from that gentleman standing in the background? Sure you would, because he's Ken Widelitz, attorney-at-law, author of Kilo- baud's Legal/Business Forum and president of COMPUTER TEXTile, the company offering those terminals. 10960 Wilshire Blvd., Suite 1504, Los Angeles CA 90024. I think I really captured the flavor of the moment here. The man on the left was a serious shopper who stopped by the Cromemco Hey, that RCA VIP (Video Inter- booth and hit Harry Garland (president of Cromemco) with some face Processor) is quite a little good questions about his system. As you can see, Harry machine! The price is kind of thoroughly enjoys himself when it comes to answering such ques- high ($275 kit), but it sure is a tions and pointing out the merits of his system. If you're shopping snap to create video patterns around, perhaps you should check into this "Cadillac" of S-100 and games. I'd sure like to see it systems. (Send for their new Spring Microcomputers/Peripherals made a little more affordable because the 1802 has a lot go- catalog—$1.) Cromemco, 2400 Charleston Rd., Mountain View CA ing for it. RCA Solid State, Box 94043. 3200, Somerville NJ 08876. That's Mike Sherrick, the de- Dr. Curt Childress, president of Midwest Scientific Instruments, is on the left with Midwest's super signer of the fantastic Malibu 6800 system . . . and their new double-sided disk system. Curt borrowed a copy of Issue #10 of Kilo- printer, and we have a review of baud and entered the Rugg/Feldman benchmarks; and he and Wayne Green are checking out the the Malibu 160 in this month's issue. (One of their largest dis- results in the photo on the right. At 1.6 MHz, the MSI 6800 came up with the following mind-blowing tributors is Jade Computer speeds: #J, .5 sec; #2, .5 sec; #3, 6 sec; #4, 10 sec; #5, 9 sec; #6, 12 sec; #7, 15 sec. Furthermore, the Products. Drop a line to Jade system can be run at even higher clock speeds! Their Catalog #2 is chock-full of 6800 boards, for more info.) peripherals and whatever. . . send for it: 220 W. Cedar, Olathe KS 66061. 0** BUS letaitcts There seems to be an abundance of S-100 disk systems hitting the market, right? Well, in the If you 6800 owners haven't checked into the line course of shopping around, be sure to look over of SS-50 bus products from Smoke Signal Broad- the capacity and software being offered with the casting then you're missing the boat! They have The Digital Group was demon- Micropolis MetaFloppy and MacroFloppy drives. a DOS that supports from 1 to 3 of their mini flop- strating a graphics system that Their Extended Disk BASIC has file-management pies . . . patches for SWTPC BASIC . . . and a co- made a lot of mouths water. and programming capabilities, and they also resident editor/assembler. They also have a 16K have a 16K DOS. 7959 Deering Ave., Canoga Park static memory board ($529), and more. PO Box CA 91304. 2017, Hollywood CA 90028. There he is, folks. The man be- Here's the group from ALF: Greg Bloom, Philip hind the CP/M Users' Group: Tubb (did you catch his "Incredizing" article in Isn't that a beauty? The new Bytemasterfrom the Tony Gold. Drop him a line. . . the April issue?) and Tim Gill. If you're into com- Digital Group . .. Z-80 based with either floppies they've got twenty-four vol- puter-generated music, these folks have some (DISKMON OS) or Phi-decks (PHIMON). They umes (diskettes) in the library top-notch boards for the S-100 bus. Send for their have a complete product catalog now. PO Box at this time! 164 W. 83rd St., catalog: 128 South Taft, Denver CO 80228. 6528, Denver CO 80206. New York NY 10024. Kilobaud the Computer Moku.IX The Frontrunner from Paraarfc When it comes to quality S-100 systems, you're going to have to look far and wide before you find something comparable to the Equinox 100. . . both electrically and mechanically. There were For those of you who haven't had the opportunity to meet our ex- three factors that accounted for the tremendous crowds around ecutive vice-president, Sherry Smythe, then allow me to introduce the Thinker Toys/Parasitic Engineering booth: George Morrow's her. Her son, Matt, is on the far right... and is one of the best new floppy interface board, which can be configured for mini or booth managers in the business. (Unfortunately, we're going to standard-sized drives, the Equinox 100 and Lauren Kawakami. have to do without his fine services for a couple of years while he Thinker Toys, 1201 10th, Berkeley CA 94710—Parasitic Engineer- goes down to Central America for some missionary work.) ing, PO Box 6314, Albany CA 94706. fCATHKTT There's Chuck Grant, president of North Why is this man smiling? Because he's Star Computers, with his arm resting on Lou Frenzel, director of computer market- one of their Horizon systems. Keep your ing at Heath, and he (along with everyone eyes open for a review of that system in an else at Heath) is tickled pink at the way Oh, yes . . . the chess tournament. What a upcoming issue. With the wide-ranging their systems have taken off in sales. Now crowd! I wasn't able to follow the action, use of North Star hardware and software their floppies are here . . and Heath's but it was sure there. My friend, Doug these days, I suspect Chuck is quite even happier! I can't tell you who that Penrod (inset), played a big role in getting pleased with what they've done. (I would gentleman kneeling down (eyeing their this event going through his "Computer have asked him, but he was too busy sell- new floppy system) is, but his initials are Chess" newsletter (which will be a feature ing systems!) 2547 9th St., Berkeley CA Steve Jobs! Drop a note to Heath and ask in Personal Computing magazine in the for their new catalog: Heath Co., Benton 94710. future). Harbor Ml 49022. MULLEN CowpujGftpiDdujcti /AMW&M tXTA PdOOOOS l&K STATIC RAM It never fails. At almost every computer Who says the camera never lies? In this convention you have at least one person photo, Bob Mullen (guess which one) ap- go berserk and try to hit master reset and pears as a thoughtful, contemplative, crash a system. I guess the strain was iust handsome and debonair designer of the Becky Sallume, of Vandenberg Data Prod- too much for Nancy Millikin .. . and I sure only S-100 logic-probe/extender board and ucts, was one of the most lively "flyer- hope she felt better after hitting that but- relay/opto-isolator control board on the hander-outers" at the Faire; but this photo ton! On the serious side, if you'd like some market; his partner, Keith Britton, appears was taken at the end of the last day! If additional info on Meca's fantastic mass- to be awake/ (Hey, check into their new you're in the market for a 16K S-100 board storage system (with a voice prompt and logic-probe/extender board. It uses a that runs cool, then send VDP some of response capability) write to them at: PO 7-segment display, and does the job your hard-earned money ($330 kit; $365 Box 696, 7026 Old Woman's Spring Rd., nicely!) Mullen Computer Products, Box assembled). PO Box 2507, Santa Maria CA Yucca Valley CA 92284. (Ask for their 6214, Hayward CA 94545. 93454. mass-storage buyer's guide.) Software Works, If that dapper gentleman looks like Dick Milewski of The Soft- Wanna draw a crowd? Put up a Digital Research Oliver Audio Engineering was looking good! ware Works, there's a good rea- sign! I don't know whether you've noticed it or Beautiful booth . . . and normally big crowds son for the resemblance! If not, but there are two pieces of software playing around it! By the way, did you know their new you're looking for a North Star- a dominating role in this microcomputer indus- PROM programmer simply plugs into an existing based inventory-control pro- try; Microsoft BASIC . . . and Digital Research's PROM socket to do it's thing (read, program, gram, they have one. (A review CP/M Operating System! Heck, you can even get verify and duplicate)? Two models—and they of the package is coming up in CP/M for the North Star drive (Lifeboat Associ- both sell for $295. OAE, 676 West Wilson Ave, Kilobaud.; Drop them a line for ates, 164 W. 83rd St., New York NY 10024) and for Glendale CA 91203. more info: PO Box 4386, Moun- the ICOM Frugal Floppy (Computer Mart of New tain View CA 94040. Jersey, 501 Rt. 27, Iselin NJ 08830)! Digital Research has a new macroassembler and sym- bolic instruction debugger, both of which will be reviewed in an upcoming issue of Kilobaud. Ver- sion 1.4 of CP/M is out, too. Drop them a line for more info: PO Box 579, Pacific Grove CA 93950. matron CUSTOMS 1H Blossom W If you're in the market for a low-cost mass-storage system, then take a look at what the folks at Exatron have come up with! It's not called a cassette... it's a continuous-loop tape wafer (called the Stringy Floppy). Each wafer holds 40K bytes; and the transfer rate is an incredible 7200 kilobaud. Loads a 4K program in about 5 seconds. The system includes an S-100 controller board (with 4K monitor/assembler/editor) and the drive for $289.50. (They also have a Tiny BASIC and a 5K BASIC Hey. .. the folks at the Com- available.) 1030 East Duane Ave., Suite I, Sunnyvale CA 94086. puter Room have a couple of beautiful business systems. The one Lawrence Grijalva is demonstrating in the photo is available with a cost-estimat- ing package (for heavy-duty construction) and inventory control. They also have a Ran- dall Data Systems machine with a BMI (Building Materials Industries) package . . . every- thing you need for running a lumber yard. 124 H Blossom Hill Rd„ San Jose CA 95123. Once again I managed to chase off the crowds Well, that should do it for tor a second to grab a shot of Dan Meyer, presi- dent of Southwest Technical Products (sporting this time. We'll finish up our a new beard). They have a new dual-drive disk TSC started off in the 6800 software business, little tour of the Faire next system (the DMAF1) for business applications but they're now offering some of the same pack- month with Part 2: more of that has a file management system called FLEX. ages (their text processing, in particular) in 8080 the people and products.— (Oh, the drives are double-sided. . . 600K bytes code. They would dearly love to send you a copy John. each.) Send for their new catalog, and include of their new '78 catalog. Technical Systems Con- $.25, OK? Box 32040, San Antonio TX 78284. sultants, Box 2574, W. Lafayette IN 47906. Bitty Computers, PO Box 23189, San Jose CA 95153.) These are not significant handicaps if you're estimating the effect of several alter- natives. Round numbers are usually acceptable if you only want to get on base in some specific ball park (cliches are Tiny BASIC Shortcuts fun once in a while). Byte-saving Tips Saving bytes of memory is a Tom Pittman's Tiny BASICs (6502, 1802, etc.) are somewhat limited practical approach if your com- in capabilities. This is the first of several articles discussing puter has limited memory (I methods to expand those capabilities. have 1250 bytes of free space now). Let's talk about the memory-saving part first. Fig. 1 is an example of a pro- gram with no statement short- Charles R. Carpenter preter's limitations. The utility • 72 characters maximum on cuts; Fig. 2 uses all the implied 2228 Montclair Place program in Fig. 1 shows how to Input lines. and abbreviated statements Carrollton TX 75006 work with some of these lim- • Implied statements and ab- possible in this Tiny BASIC in- itations. This program is titled breviations to save bytes of terpreter. Memory in Fig. 1 is "Loans," but it could be any memory. 492 bytes, an average of 17 comparison of WHAT-IF alter- (Note: Tom Pittman now has an bytes per line, while Fig. 2 uses riting small but useful natives. Here's what we'll be experimenter's manual avail- 410 bytes for an average of 14 Wprograms in Tiny BASIC working with (and without): able that explains many of bytes per line. REM comments (to paraphrase Tom Pittman) is • Decimal numbers not al- these features and how to work were added later and used 470 a practical reality. Getting the lowed. with them. They are not as sim- bytes. most out of your programs is • Number range limited from ple as my approach. The Using implied statements easier if you work with the inter- -32768 to + 32767. manual is available from Itty causes the program to run 220 LET A = A + 1 :LIST 230 PRINT 10 REM TINY BASIC FOR KIM-1 240 PRINT"LOAN NUMBER ";A;"" 11 REM 6502 V.IK BY T. PITTMAN. 250 PR I NT" INTEREST IS $";l 12 REM 260 PRINT 13 REM PROGRAMMED BY: 270 PRlNT"MONEY OWED IS $";0 14 REM C.R. (CHUCK) CARPENTER W5USJ 280 PRINT 15 REM 2228 MONTCLAIR PL. 290 PRINT"PAYMENTS ARE $";M 16 REM CARROLLTON TX 75006 300 PRINT 17 REM 310 LET N = N - 1 18 REM THESE PROGRAMS ILLUSTRATE BYTE SAVING 320 IF N>0 THEN GOTO 170 19 REM TECHNIQUES IN LIMITED MEMORY SYSTEMS. 360 PRINT 20 REM THE FIRST PROGRAM USED 492 BYTES. THE 370 PRINT"DONE" 21 REM OTHER USED 410 BYTES. AN INCREASE 380 PRINT 22 REM (OR SAVING) OF 82 BYTES. IMPLIED 390 END 23 REM STATEMENTS AND ABBREVIATIONS ARE 24 REM THE REASON. 25 PR 26 PR 100 PRINT"LOANS : HOW MANY 1 = 0 110 INPUT N 1 I = 1 + 2 115 PRINT 2 GOSUB 1 120 LET A = 0 RUN 130 PRINT"INPUT: PRINCIPAL IN HUNDREDS (P)" 140 PRINT" RATE IN PERCENT (R)" !226 AT 1 150 PRINT" TIME IN YEARS (T)" END 160 PRINT" PAYMENTS IN MONTHS (X)" 170 INPUT P,R,T,X :PRINT"THERE ARE ";I;" BYTES LEFT" 190 LET I = P*T*R THERE ARE 288 BYTES LEFT 200 LET 0= 100*P + I 210 LET M = 0/X Fig. 1. First program version using no shortcuts to write the program or save bytes. This program uses 492 bytes, exclusive of the REM statements. REM statements use 470 bytes. The short routine above illustrates how Tiny BASIC finds the number of bytes of free space remaining. The user's manual tells how to do it. slower, but the increase in pro- reason, accountants would by the prompting question data. I've done this on some gram lines is worth the loss of probably not want to use Tiny mark and following space. This data-processing routines with speed (if speed is your concern BASIC.) reduces actual data input to 70 good results. then Tiny BASIC may not be for Lines 130 through 180 are the characters, including the re- There's another way to ac- you, anyway). Memory saving input lines for this program. I quired commas between the commodate more data than the wasn't really necessary for this used principal in hundreds and data entries. With the loan line will hold. Simply input as short program; but in a 100-line rate in percent to avoid decimal amount in hundreds, I was able many loan numbers (or WHAT- program over 200 bytes could percentage entry and to pre- to input values for six loans in- IFs) as needed in line 100. When be saved (12 to 15 lines' worth). vent dividing percent by 100 (to stead of five. To overcome the the program has used the data Such significant savings allow get back to a decimal percent- limited data-input situation, entered, it will ask for more un- you to write longer programs. age). The math comes out right write programs that will per- til the number of N entries is The programs are still small, when it's printed out in line 250. form calculations, hold the reached in line 320. Question but even a few more lines make I then multiplied the total loan results and return for more marks will show up each time them more useful. And that's value by 100 in line 200 to make what we're trying to do. Bytes the right amount print in lines could be saved in a few more 270 and 290. places, such as the spaces in Principal input in hundreds the print input, lines 130 LOANS: HOW MANY - also helps avoid the number- ?6 through 160, but in the interest limitation problem. Keeping the of clarity, I left them alone. numbers to be operated on INPUT: PRINCIPAL IN HUNDREDS (P) small limits precision but RATE IN PERCENT (R) TIME IN YEARS (T) Decimal Values keeps the multiplication re- PAYMENTS IN MONTHS (X) Calculations involving sults in range. Adding a state- decimal numbers can be han- ment in a print line to multiply ?40,10,3,36,40,12,4,48,40,18,5,60,50,10,3,36,50,1 dled several ways. Anytime a (or divide, etc.) by some factor 2,4,48,50,18,5,60 percentage or a calculation will put the answer back in the LOAN NUMBER - 1 right magnitude. This is sort of resulting in a fraction occurs, a INTEREST IS $1200 decimal number results. like using engineering notation Dollars and cents are decimal with a slide rule. The difference MONEY OWED IS $5200 numbers, too. Tiny BASIC trun- is the lack of decimal numbers. PAYMENTS ARE $144 cates decimal numbers down An input-line limitation of 72 to the next lower whole num- characters restricts the LOAN NUMBER - 2 ber. If the number is less than amount of data you can input. INTEREST IS $1920 one, the result is zero. (For this Two character spaces are used MONEY OWED IS $5920 PAYMENTS ARE $123 :LIST LOAN NUMBER - 3 INTEREST IS $3600 100 PR"LOANS : HOW MANY -" 110 INPUT N MONEY OWED IS $7600 115 PR 120 A = 0 PAYMENTS ARE $126 130 PR"INPUT: PRINCIPAL IN HUNDREDS (P)" 140 PR" RATE IN PERCENT (R)" LOAN NUMBER - 4 150 PR" TIME IN YEARS (T)" INTEREST IS $1500 160 PR" PAYMENTS IN MONTHS (X)" 165 PR MONEY OWED IS $6500 170 INPUT P,R,T,X 190 I = P*T*R PAYMENTS ARE $180 200 0=100*P + I 210 M = 0/X LOAN NUMBER - 5 220 A = A + 1 INTEREST IS $2400 230 PR 240 PR"LOAN NUMBER - ";A;"" MONEY OWED IS $7400 250 PR"INTEREST IS $";I 260 PR PAYMENTS ARE $154 270 PR"MONEY OWED IS $";0 280 PR LOAN NUMBER - 6 290 PR"PAYMENTS ARE $";M INTEREST IS $4500 300 PR 310 N = N - 1 MONEY OWED IS $9500 320 IF N>0 GOTO 170 360 PR PAYMENTS ARE $158 370 PR"DONE" 380 PR DONE 390 END Fig. 2. Second program version using implied statements and Fig. 3. Sample run. Simple interest calculations of two different abbreviations to save bytes. This version uses 410 bytes. loan values at three rates. From Fig. 3 From Fig. 5 Simple Int Compound Int LOANS: HOW MANY - ?3 lnterest% Years Amount Equlvlnt% Years Amount 1. 10 $5200.00 11 3 $5320.00 INPUT: PRINCIPAL IN HUNDREDS (P) 2. 12 5920.00 15 4 6400.00 RATE IN PERCENT (R) 3. 18 » 7600.00 26 5 9200.00 TIME IN YEARS (T) PAYMENTS IN MONTHS (X) Mult Actual Loan Value Difference ? 40,11,3,36,40,15,4,48,40,26,5,60 1. 1.331 $5324.00 + $ 4.00 2. 1.574 $6296.00 - 104.00 LOAN NUMBER - 1 3. 2.288 $9152.00 + 48.00 INTEREST IS $1320 Fig. 4. For a loan of $4000. MONEY OWED IS $5320 PAYMENTS ARE $147 line 170 runs out of data and value Is input for N is LOAN NUMBER - 2 decremented in line 310 until line 320 is still greater than INTEREST IS $2400 zero. the data sets, input in line 170, This program only calculates are used up. The counter that MONEY OWED IS $6400 simple interest loans. Com- starts in line 120 numbers the PAYMENTS ARE $133 pound-interest calculations re- printed output each time a pass quire decimal numbers and through the program is com- LOAN NUMBER - 3 raising numbers to some pleted. INTEREST IS $5200 power. The multiplier for com- I tried to use N to do both, but pounding over n periods is could not without using more MONEY OWED IS $9200 n program lines. Otherwise, this (1 + l) , where I is the interest PAYMENTS ARE $153 expressed as a decimal and n is is simply a fundamental pro- the number of years (or gram with input between lines DONE periods). 100 and 170, calculations be- Fig. 5. Loan value two, rerun to show the effect of compound in- You can use this multiplier to tween lines 190 and 220 and out- terest on the total loan value. Compare the results with the sim- calculate the approximate put between lines 240 and 290. ple interest calculation. equivalent while percentage over the term of the loan. Your Summary calculated answer will result in It is easy to save bytes of a much more realistic loan memory if you remember to use evaluation. I made some of implied statements and state- etc.). Line input characters until you reset your system. If these calculations, and Fig. 4 ment abbreviations. The user's limited to 70 (72 with prompting you have to reset and want to has some examples. manual for Tiny BASIC shows question mark and space) can save the program already in In the program itself, there what is, and is not, allowed. also be handled by pro- memory, then reenter the inter- are no unusual or unique pro- Both the decimal number and gramming techniques. preter at the soft entry point. gramming techniques. There number range limitation can be Remember, if you input more The Tiny BASIC user's manual are two counting loops—one handled by using software than a total of 72 characters in explains how to do this, too. A starting at line 110 and the math techniques (multipliers, a single line, the program will program does not have to be other at line 120. Whatever dividers, engineering notation, stop. Nothing more will happen big to be useful.• Datapoint CRT Terminals NortliStaf Software RAINBOW COMPUTING INC. 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SPSS, BMD's Terms COD Residents add 6% sales tax and St 00 shipping M-33 KSR Teletypes $595 ASR 33 $735 Call us for service on CRTs, micros, main-trames COMPASS, MACRO. 6800, & Z80 assembly languages Leasing. Quantity discounts available Alpha Data Systems A48 TELECOMMUNICATIONS SERVICES CO. 10723 White Oak Ave., Granada Hills. Ca. 91344 Box 4117. Alexandria. Va. 22303 (213)360-2171 R1fl Box 267. Santa Barbara. Ca. 93102 • 805/682-5693 703-663-4019 I TLX 89-623 T26 Try COMPUTER DIGEST... And Get A Digest of EDP & Scanning News Without Risk By subscribing to COMPUTER DIGEST, you problems, because you will be more knowledge- have the facts you need about computers and able about computers and optical scanning. optical scanning. With this information, you can act immediate- • It's a timely summary of what is being ly on new business opportunities. Subscribe and written about computers and optical scanning in each month you get: the business press. 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We have found this is software. the best way to introduce businessmen to this • Not only can you find new markets, but newsletter. This way, we take all the risk, so you the reports will help you solve customer have nothing to lose by trying this publication. CLIP AND MAIL- Send to: COMPUTER DIGEST North American Building, 401 N. Broad St., Philadelphia. PA 19108 send me COMPUTER DIGEST, also incorporating OPTICAL • Bill company for $40 Yes, SCANNING NEWS. I understand I can look at 2 issues, and if not • Bill me for $40 satisfied, I will owe nothing. I can write "cancel" on the bill, and owe nothing. If I like the newsletter, I will pay the $40 bill I receive. • Payment enclosed Name- -Title. Company. Address — City/State/Zip fM % * Computer Digest is published by North American Publishing Company, leaders in editorial excellence. KB/6/78 Howard L. Nurse 665 Maybell Avenut Palo Alto CA 94306 Baudot... er... Murray, Meet the H8 There is an inexpensive way of obtaining reliable and quiet hard copy for your home system; and an old five-level code teletypewriter is the answer. H8 system. Baudot printers use bols to cover the desirable ments by modifying the lookup Publisher's note: The Baudot referred five information bits, rather ASCII characters not available table used in the driver program to in this article is actually Murray code as per my remarks on page 4 than the seven bits used by in the Baudot set, the missing to convert ASCII characters Have we all been the victim ol a characters can be accom- generated in the computer to dastardly French revisionism plot? ASCII printers, to print 52 char- acters. Even though ASCII tele- modated. The following assign- Baudot characters. printers can print many more ments have been made in this Hardware audot teleprinters, fre- characters than Baudot ma- driver: chines, there are only a few pro- The ASCII/Baudot driver was Bquently available as sur- Backspace = X gramming characters lacking written for the Heath H8 com- plus for next to nothing, can be Percent (%) = (C) in the five-level printer. puter system. This documenta- used with the driver described Asterisk (*) = (X) here as a listing device for your By assigning arbitrary sym- tion assumes that the interface Plus( + ) = (P) to the teleprinter will be made Less Than (<) = (L) via an H8-2 parallel I/O port. Equal ( = ) = (E) Since Heath software makes Greater Than (>) = (G) no distinction between serial Integrated Circuits At (@) = (A) and parallel ports, an H8-5 U1 AY-5-1013A UART -12 Required Left Bracket ([) = (B) serial port can be used. How- on Pin 2 Reverse Slant (\) = (R) ever, you will normally have a U1 (Alt.) AY-3-1015 UART -12 Not Right Bracket (]) = (B) Required CRT console already con- Up Arrow (t) = (U) U2 NE555V Timer nected to a serial I/O port, with Underline (_) = (-) U3 SN7404N Hex inverter the second port on the board automatically committed to the You can make arbitrary assign- Resistors R 1 18k, V* W R 2 50k, 10 Turn Potentiometer R1 I6K R 3 47k, V« W u 7 VCC TRC RJ R 4 1k, Va W 47 K EPE U2 NE5S5 CLSI Capacitors CLSZ JO, J R2 GNO SFIS 50 K C 1 .01 uF Disk Ceramic 6 can be obtained for $71.25 (plus tax in California) plus $2 A N C FOR 5 VOLT UARTS - 12 VOLTS FOR ALL OTHERS (SEE PARTS LIST) postage and handling. B ALL RESISTORS 14 W 10* C ALL CAPACITORS IN UF D H&-2 110 CONNECTIONS AT END OF HB-2 CABLE Table 1. Interface parts list. Fig. 1. H8-2 to external UART interface. in the same way as for an H10. H8-2 Interface UART Interface Software The ASCII/Baudot driver Signal Function Pin Wire Color Flow Pin Function uses a lookup table to convert the ASCII character being sent White-Black - 11 TBR1 Data 0 1 to the system console to a Data 1 2 White-Brown — 12 TBR2 Baudot character compatible Data 2 3 White-Red — 13 TBR3 with a five-level teleprinter. The Data 3 4 White-Orange - 14 TBR4 routine is placed at the upper Data 4 5 White-Yellow — 15 TBR5 Data 5 6 White-Green — 16 TBR6 end of user RAM, just below the Data 6 7 White-Blue — 17 TBR7 stack, where provisions have Data 7 8 White-Violet — 18 TBR8 been included in Heath soft- Ground 9 White-Gray 24 GND ware to allow user memory Data Taken 10 Red-Black — 21 TRE space. Take Data 11 Red-Yellow — 20 TBRL The Heath software must be 12 Red-Green Device Cntrl reconfigured to allow the ASCII/ Device Rdy 13 White-Black-Red Baudot driver to be used. The Device Cntrl 14 Pink changes include: (1) redefining Send Data 15 Tan Data Sent 16 White the high-memory limit as de- Ground 17 Gray tailed in Table 3; (2) changing Data 7 18 Violet five memory locations in each Data 6 19 Blue Heath program, as shown in Data 5 20 Green Table 4. Data 4 21 Yellow Once the Heath software has Data 3 22 Orange been reconfigured, the ASCII/ Red Data 2 23 Baudot routine is loaded with Data 1 24 Brown the Heath program. The ASCII/ Data 0 25 Black Baudot driver need only be Table 2. H8-2to UART interlace. loaded once when going from one Heath reconfigured pro- cassette tape I/O. A second serial I/O board could be used, but an unusable tape I/O port would result. A universal asynchronous re- ceiver transmitter (UART), hex- inverter integrated circuit, Baudot clock and 60 mA loop circuitry are required to com- plete the interface. A sche- matic and parts list for this out- board circuitry are given in Fig. I and Table 1, respectively. The baud-rate potentiom- eter, R2, should be adjusted to a frequency 16 times the tele- printer baud rate. If the tele- printer has 60 wpm gears, the clock rate should be 727 Hz; if the machine has 100 wpm gears, the baud-rate clock should be adjusted to 1187 Hz. Table 2 shows the connec- tions that must be made be- tween the interface circuitry and the H8-2 parallel I/O con- nector. The parallel I/O cable is wired as recommended by the H8-2 parallel I/O manual for the H10 tape reader/punch. Finally, the jumpers on the parallel I/O channel should be configured Fig. 2. Program flowcharts. Examples: MSB 7 6 5 4 3 2 LSB 1. Assume A is the ASCII character. [_ 1 = Left parenthesis Binary byte for A is 00001100. 0 = No parenthesis Octal equivalent of binary byte is 1400. Baudot machine prints A. 1 = Uppercase (FIGS) 2. Assume = is the ASCII character. 0 = Lowercase (LTRS) Binary byte for = is 10000101. Octal equivalent of binary byte is 2050. Baudot character Baudot machine prints (E). 3. Assume 5 is the ASCII character. 1 = Right parenthesis Binary byte for 5 is 01000010. 0 = No parenthesis Octal equivalent of binary byte is 1020. Baudot machine prints 5. Fig. 3. Lookup table byte structure. gram to another. For example, the following describes a 1. Load Distribution Tape. typical use of the driver with the 2. Change High Memory using Reconfigured High Memory below. H8 editor and assembler. 3. Change Pad from 4 to 1 (optional). 4. Record Heath program using "SAVE." 1. Load ASCII/Baudot driver 5. Proceed to instructions on Table 4. from cassette tape. 2. Load reconfigured H8 Total Actual Dec- Actual Oc- Begin Equ Reconfigured editor. User RAM imal Limit tal Limit High Memory 3. Push GO. The Baudot 4K 12287 057377A 056000A 11775 printer will now print each 8K 16383 077377A 076000A 15871 character sent to the CRT, with 12K 20479 117377A 116000A 19967 substitutions where required. 16K 24575 137377A 136000A 24063 4. Write and/or edit source 20K 28671 157377A 156000A 28159 24K 32767 177377A 176000A 32255 code. 28K 36863 217377A 216000A 36351 5. Save source code on cas- 32 K 40959 237377A 236000A 40447 sette tape. 6. Load reconfigured H8 as- Table 3. Reconfiguring Heath programs. sembler. 7. Push GO. The assembly will proceed normally, with all information printed on the CO — — oc CO Baudot teleprinter. X o — »O CO UJ V) UJ UJ (_> W) UJ O ac O X UL X T/> o CO UJ QC X CC — OC X »- 3 o x O A= UJ x 3 co Flowcharts for the driver are x o — 3 3 a a a z o o — O UJ X ox H— oc • CC>-QXQQCC_)UJ UJ oo u. zw>t9 u. 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