digital group computers - the real story

by Dr. Robert Suding

It's difficult to know just where to start, but I think the real start for me and microcomputers just may be around 1972. I had been a serious ham radio operator since 1953, always designing & building my own transmitters, amplifiers, antennas, and sometimes my own design receiver for use on the amateur radio bands from 1.8 MHz through 10,000 MHz. I never had any formal training in Electronics. I just taught myself. My education was as a Latin Teacher. But in 1967, I left teaching and joined IBM in Denver as a field engineer and became a specialist on the IBM 360/20 computer in hardware and software. I loved CPU and Telecommunication problems and had the IBM 360/20 machine language down cold.

I went to Florida State University in 1972 to get my Ph.D., intending to eventually lead the IBM Field Engineering schools. It was at this time that I really started using the bugs - Integrated Circuits - the 7400 family. I never cared for transistors, but the bugs really appealed to me. I designed a Slow Scan Television keyboard that year; that's why I think 1972 was the real beginning for me. It used about 3 dozen TTL bugs, TTL memory and a 2513 character generator. Over the next couple of years I designed transmitting and receiving scan converters for SSTV and had them published in several ham magazines. It was a radical departure from anything I had ever done.

At the same time, unknown to me, Frederico Fagin at intel designed and made a special Integrated Circuit, later known as a 4004, for a use in an adding machine. This adding machine company was infamous for always making adding machines that were perfect unless you plugged them in. The contract fell through and intel had a meeting with Fagin to figure out what the Hell they were going to do with the 4004. The conclusion was the 4004 might have a future as a stop light controller, and intel estimated that the total world wide market for microcomputers in the foreseeable future would be 1000 a year!

Meanwhile, back at IBM, I wandered through several yucky assignments. In the Spring of 1974 I went down to a ham convention in Pueblo, Colorado where I was invited to give a talk on my IC designs used in SSTV equipment. I was wandering around the flea market area later, and ran across a fellow with a strange looking box with a row of LEDs and a row of switches. So I asked him what it was. He said it was a microcomputer. His name was Larry Williams, and the computer was put out by Scelbi using an intel 8008 microcomputer, a successor to the never popular 4004.

So I asked Larry what it did. "It blinks its lights left and right", Larry said. I asked Larry to make it blink its lights left and right. "Can't", Larry said. "We just lost electricity and it will take a 1/2 hour to put the program back in memory." My big chance to see my first microprocessor run - down the drain. Two years later Larry worked at dg and was responsible for the floppy disk controllers. Larry loved the latest parts. So did everybody else so often the disk drive controllers couldn't be shipped because we couldn't get the controller IC.

In July, 1974 what should appear but an article in Radio & Electronics magazine on a microcomputer, the Mark-8, that you can build yourself. PCBs and parts availability were shown. I thought to myself, "anything this DUMB, I've got to get into." So I sent away for the PCBs and parts. I remember the 8008 was $50, big money in those days.

The parts for the Mark-8 arrived a week later, and I assembled everything in a few weeks. But right off, I didn't like what I saw. The 6 PCBs were double sided, but did not have plated through holes. Instead, you had to put a wire through each via and solder it on both sides. The PCBs had no edge fingers so you could plug them in. Instead, on each card was a matching set of 41 holes that you dropped a long piece of #22 bare wire through and soldered each wire to each side of the six boards. To service a card, you "unfolded the deck". A couple of times and the wires started to fracture and you had another problem. Years later I asked Jonathan Titus why he made the PCBs this way. He said Radio-Electronics told him to do it that way because they saw no future in microcomputers, "so make the PCBs as cheap as possible." A set of boards consisted of a CPU board, an Address board, a memory board (256 bytes), an Input board, an Output board, and an LED board for $47.50. A set of parts from intel including the 8008 and several weird ICs cost $120.

I made several changes. I had better things to do in life than decode binary bits, for sure. So I got rid of the LED board and made a front panel that decoded the binary into Octal, displaying the addresses and code on several 7 segment LEDs. I also got rid of all the switches and put in a front Octal keypad. Other designers came from a PDP-8 background with its lights and switches. The IBM 360 was loaded by punched cards. Even the front Octal keypad was a pain, so I connected a standard ASCII keyboard. I designed and made a 32 x 16 character video display board with output to a standard NTSC TV set or monitor. The best thing was an audio cassette interface and a Programmable Read Only Memory (PROM) interface that allowed me to save programs and quickly restore them in case of an electrical outage. And it all worked great by the end of the Summer, 1974. But a snowball stands a better chance in Hell than most hobbyists have of ever getting a Mark-8 to run.

An enterprising teacher, Hal Singer, and students from Cabrillo High School in Lompac, Ca. started putting out a "Mark-8 User Group Newsletter" in September, 1974. It listed the names and addresses of all Mark-8 interested parties in this pre-Internet era. It also published suggested circuits and low cost parts sources, many of dubious character. I complied a list of 18 Colorado guys mentioned in the newsletter as interested in the Mark-8. I called each one, and told them, "I've got one running and if you drive over to my house in Lakewood, Colorado Tuesday night, you can see it. Immediately I had 18 strips of rubber converging on my house.

Everybody was delighted with what they saw, especially Dick Bemis. Dick's parents were into Geothermal Wells in Utah, while poor Dick was doing software support for IBM in Denver. I was the answer to a maiden's prayer. After the dog and pony show, Dick came up to me and asked what I was going to do next. I told him that I would probably just Xerox off the circuitry and sell it at cost. Dick's eyes lit up and he said that he would handle everything if I would do the original effort. We did some calculating and figured we would break even if we sold about 100 copies at $7.50 each. We under estimated the market like everyone else; we eventually sold 575 packets that included schematics and software on an audio cassette. A month later, Dick, his wife, my wife and I incorporated the digital group. Dick reserved 51% of the shares for himself and generously gave me 10%. I thought this was rather unfair, since it was all my designs, but Dick informed me that he was a financial wizard so he deserved 5 times as much as me. Time proved otherwise.

The $7.50 MARK-8 packet customers leaned on us to make PCBs of the video design and the cassette based software design which became our first real products. Our estimate on the demand was way low on these items too, thinking we would sell maybe 75, and eventually sold about 300.

The January 1975 issue of Popular Electronics featured a new microcomputer design too. Unlike the DIY Mark-8, the MITS Altair 8800 arrived all built for $400. It used an 8080 instead of the 8008 disaster. Since I knew the 8080s were going for $200 each, I could not understand how they could produce a whole box and sell it for $400. I later found that intel had cut a special ~$65 each deal with MITS. intel probably lost a bundle on the MITS special deal, and are crying all the way to the bank about it. The Altair as it arrived didn't do much except blink its lights left and right, but it was a major hit in the appliance market, from a company whose previous product line was a windshield wiper control box, sold in the days before it was included with your car.

Dick gave me the tycoon look, and said he wanted to get in on the real action. Though he favored an S100 bus as the Altair design was called, I favored a CPU independent bus, as it was apparent to me that the customer would be the proud possessor of a totally obsolete box every other year. We argued it over and decided to make a CPU independent motherboard, a CPU board for the latest intel offering, the 8080, an 8KB static memory board, an I/O board and a video board with 64 characters across using a 7x9 dot matrix character generator chip from Motorola. A couple of years later, Dick brought out a couple of dg S100 boards but they were a total bust as I predicted.

One of the IBM corporate managers and former IBM Boulder plant manager was one of the Denver area hobbyists that attended my original Mark-8 meeting. Subsequently I taught him all about this new world of microprocessors. In the Spring of 1975, he pulled a few strings and got me a temporary assignment to the Boulder plant, working on a top secret microprocessor and ink jet based copier designed to compete head on with XEROX in 10 years. Inkjet technology was new in those days. Engineers came to work in white shirts and left work with a blue shirt. The processor was called the OPD Mini. It was a 4 bit processor with a total of 16 instructions. It was a primitive throwback at best and the scanning system was a subset of the SSTV designs I had made years before. The department managers were imports from the Typewriter Division in Kentucky and had no idea what they had going on. They assigned me to develop the transport code keeping track of paper flowing through the copier. After the 8008, this simple minded IBM 4 banger was a total yawn. I was given 1 month long due date projects, and I kept completing them in one afternoon. Finally I went up to the management and told them I had not had a raise in a couple of years in spite of obtaining my Ph.D.. I wanted an immediate promotion to Staff engineer and double my existing salary which was well below that of a beginning engineer. I promised that I could cut a year and a half off their development schedule and turn out a superior product. I talked it over with Dick that night and he agreed to minimally support me and my family until dg grew. The next day the IBM managers told me that there were no transfers at that time, but if I "kept my nose clean", they would think about me in 6 months. Not a good answer. I told them I was quitting that day. Bye. Three lawyers read me orally what I knew about the top secret copier project and should never repeat, especially to Xerox. Second level upper managers pleaded with me to stay, telling me what a wonderful job I had. I wasn't convinced. Best decision I ever made.

For the next four years I worked on dg microcomputers, usually in my basement. I designed them 16 hours a day, 7 days a week and got used to having 4 hours of sleep a day for the four years. It was the happiest time of my life.

Motorola wanted to get in on the up and coming microprocessor action, so an engineer by the name of Chuck Peddle and his team put together an interesting microprocessor for them, called the MC6800. This microprocessor was adopted by a company in Utah called Sphere. Sphere never ran well and quickly disappeared from the microprocessor scene, but left a number of anxious investors and parts distributors with real money losses. Later MITS brought out a 6800 based box too, but it never did well either. Undaunted by all this I designed a 6800 CPU board for my CPU independent motherboard and I/O, and it worked fine. But I never cared much for the 6800 because its address bus was dynamic, and when I tried to single step it, all I got was all 1's for address out to my static RAM.

Shortly after all this Chuck Peddle and team left and joined MOS Technology, famous for making digital clock and calculator ICs in Pennsylvania. I got an early sample of their initial chip, the 6501, and modified the 6800 board very slightly to take it. Then I called Chuck to tell him I had it running. Chuck told me about another chip in design called the 6502, identical to the 6501 in software, but quite different in hardware layout, even including an internal clock generator. Chuck and team swung by my house in Lakewood for a visit and promised me anything I wanted. Chuck did the same thing with the Apple founders and they took him up on it. I preferred the 6501 to the 6800 because if I had a problem CPU PCB, I could pop out the dynamic 6800 and put in a static 6501 and new boot code EPROM and quickly single step through the problem software.

Predictably, Motorola sued MOS Technology about that directly compatible 6501 thingie. Chuck apologized to Mitch Motorola, and said he would not market the 6501. All was forgiven, and Chuck brought out the 6502 which was what he wanted to do all along. Wozniak designed the Apple 2 around the 6502 and the rest is history. I made a 6502 board for the dg CPU independent motherboard and we sold a number of them, but it wasn't my first choice IC.

Frederico Fagin, the real father of microprocessors, left intel to form his own company, Zilog. Intel was somewhat pissed by this display of independence and proceeded to erase Frederico from all company stationary, kinda like the new Pharaoh erased the old Pharaoh's name from all the monuments, obelisks and pyramids. I read about Frederico's new chip, the Z-80, in some Electronic magazine of the time. It was supposedly compatible with all 8080 code and added a lot of 16 bit math double register routines. "Yummy," I said to myself. This is a real microprocessor that can do 16 bit math and 16 bit (full 64K) vectored addressing (poorly). It cost $250 each, but if it worked as advertised, it would be worth every penny. Dick was convinced and bought me a couple. I took a saber saw to one of our 8080 boards, and got it running in about two days, using the old 8080 code. It worked great. I then upgraded the 8080 machine code to include the new 16 bit Z-80 codes.

About 2 weeks after receiving the Z-80s, Dick and I took our computers to the National Computer Conference in New York City. Dick had visions of grandeur getting into the business world of microcomputers, but I saw us buried trying to just keep up with the hobbyists. About 50' away from our dg booth was the Zilog booth and Frederico. Frederico was in a very interesting position. His company was unknown, but we had a very loyal hobbyist following. He kept wandering by our booth trying to figure out why we always had a crowd and he had one or two people, tops. I remember one time when Frederico came by complaining about the lack of interest people had in his booth. I said, "Watch this." I took the cover off one of the dg computers and put an AM radio tuned to the low end of the broadcast band on top of the memory board. Then I loaded a special program I wrote which modulated the memory board noise. When I hit start on the keyboard, the computer slowly printed out the flag on the screen while the radio played the Star Spangled Banner. In less than 2 minutes we had a crowd of 50 people watching this happen at our booth. Those were fun days!

Frederico never had a chance to try out his own product, so each morning before the show opened, I showed him how a Z-80 worked. About this time TI, National, and AMD had also gotten into the 8080 production game. But they had all made some minor internal coding errors and I had a program which could access these differences and print on the screen what brand of an 8080 was used in a computer. I told this to Frederico and he got real worried. I loaded the program and it read out that it detected an intel 8080. Frederico was relieved; his boys had copied the right chip.

dg started out in 1974 with 5 people. 3 of them were worthless but each was given 5% of the dg stock. After about 6 months Dick left IBM to become the full time pontiff of dg. In 1976 the workers grew to around 20. In 1977 it grew to around 60 employees and finally peaked in 1978 at 105 employees. Dick was el supremo and did all the hiring. I never could figure out why he hired people. It certainly was not because they had talent. Often it was because Dick and they were friends or acquaintances. Well, I did the same thing. I often got people, like the boy next door and several hobbyists that I know, jobs at dg. But I knew they had talent. Dick hired many that were cheap, many unable to speak English, much less knew anything about computers or even electricity. If a sack of nuts were placed in the front of these people they would put nuts in the kit instead of resistors!

Quality Control was nonexistent. "Assembled and Tested" computers were shipped without ever being plugged in. 80% of the shipments return as nonfunctional. I went ballistic before Dick and he hired a Detroit hobbyist by the name of Ken Jackson to be QC. Ken was sharp. At least he knew when a computer was not running! But the manufacturing duds found that their computer duds weren't getting by Ken and they were running way behind schedule. So they complained to Dick and Dick solved the problem. He fired Ken.

In mid 1978 I stopped any further designs, and became QC. No duds got by me. I think most people got a good system eventually, but often it took customer effort on the phone to get things straightened out.

I was officially the VP of engineering. Didn't mean much. With my teaching experience I was the front man at conventions, helping hobbyists, giving talks at conventions on microcomputer applications. Only the creditors knew Dick. Dick said he would handle manufacturing and sales. He was a silver tongued devil that could get a 90 day line of credit from anyone. But those early days of microcomputers showed explosive growth (we grew 25% a month for the first 2 years) and all the supporting industries were anxious to cash in.

The initial microcomputer devotees were all hobbyists. In 1975, dg could provide a bare bones kit w/o case to them and they could put it together in a month with a high probability of success. I spent about a 1/3 of my day helping hobbyists with problems. In 1975 these hobbyists paid cash for their kit and cash flow was great. As a kit company, very few employees were needed, and we could have been very profitable.

But in 1976 we saw a significant change. The demise of Sphere sent serious ripples through the industry. Sphere probably died on customers' money; even those that got something found it didn't work right and was unsupported. At least that was the sentiments told to me. Hobbyists are a vocal group and news like this travels real good. Towards the end of 1976 we saw a significant shift in the buying habits of the hobbyists. It went from a totally cash up front basis to a significant amount of C.O.D. And I started to get wind of a change in delivery of goodies ordered. I was the convention front man, and so complaints gravitated to me real quick. What was happening was a clear case of negative cash flow. Payroll was not supported by income. If a hobbyist paid cash, it was a sure thing that he would be the last to get the goodies ordered, because his goodies went to the C.O.D. customer so C.O.D. money could be received.

The problem got worse in 1977, and by 1978 suppliers who had been regularly receiving late rubber checks finally got wise and would only provide us with needed parts upon receipt of a cashier's check. If you manufacture a computer with 3000 parts, and you can't get one, you can't ship. If you can't ship, you can't get the C.O.D. You get the picture.

Other companies were going through similar misery and a number of them folded. Apple founders survived because they were wise enough to look for outside cash infusion. This was anathema to Dick. He wanted to control the dg, and he did. Right into the ground. 1978 spelled major doom for dg. We always had a more orders than we could fill. One time I opened a closet door at dg and found about 3000 bingo cards from dg magazine ads from hobbyists wanting more information on a dg computer. I was told there was no money for stamps to send the dg brochure out. Debt was out of control with no relief possible. Industry was looking at buying up these hobbyist industries to get on the microcomputer bandwagon with a running start. Ed Roberts sold MITS to a minicomputer company and retired very wealthy. MITS died soon thereafter. On a couple of occasions a stretch black Cadillac pulled up to the dg plant and some interesting characters climbed out to see Dick. I always wondered if an irate creditor had put a contract out on us. But they were just looking for a company to buy. None bought dg. Surprise, surprise.

Dick got the idea that dg should cater to business applications rather than all these troublesome hobbyists. So he enticed several of his former IBM software support buddies to leave IBM in mid 1978 and then Dick leased the top floor of a building in Cherry Creek, the most expensive area in town! Dick never mentioned this to me, but my spies, whose paychecks had bounced the week before, did. I showed up unannounced at the top floor to the embarrassment of all.

Finally in early 1979 the expected happened, dg declared Chapter 11 bankruptcy. Boy, did this hurt Dick's pride. We had a massive layoff down to 25 good employees and finally started turning out dg computers. But the creditors, lead by Hamilton Avnet, the most severely burned, did not accept Dick's repayment plan (I wonder why), and dg died in early Summer 1979. The final tally of computers built was about 3000. We had gone about $2000 further into debt for every computer shipped.

Aftermath - I moved to Virginia largely to get out of town in case of aftershocks. I became Chief Scientist at GTE Telenet, tripling my salary at IBM four years before, and heard that at one time Telenet was consider buying up dg just to get me. I lost contact with Dick Bemis after that, but someone told me that he had started and folded a couple more companies in the Denver area. I moved back to the Denver area in 1985 and a few years later ran into Dick at a computer book store. Dick asked me what I was into these days and I told him Neural Nets. Dick Bemis told me, "we can form a company called the neural group!"

WRONG!

Final Price List Brochure from the digital group - Spring 1979

Most of the equipment at this time was no longer going to be delivered. In fact, much of it never existed. dg was in Chapter 11, and this brochure was probably published to convince the court and creditors that dg was a viable operation. It didn't work. I thought you might be interested in the original prices. Bear in mind that an equivalent car was about 1/3 the price it is today. Our 3 bedroom house in Lakewood, Colorado sold for $62K in 1979. Today it would go for over $200K. dg always had an order backlog - just no money to fill the order.

My personal dg Computers and Software

Here are some of my dg equipment and software holdings dating back 25 years to dg times. Not being a collector, I have already tossed several dozen boards and my Mark-8. My wife tells me I should post these on E-Bay. I will most like sell them as packages e.g. hardware and software. Several have contacted me expressing interest in the items below, so if interested just e-mail me and I will keep you informed. I have not run this equipment for many years, but most should still be running fine.

Bytemaster. Has a pair of 8" floppies that can used with either single or dual density floppies, either soft or hard formatted. Dick loved this design because it had no screws showing. Dick loved brown. dg had more trouble with cases than everything else combined. The cases were custom made by a sole source that Dick had a habit of not paying. Finally it was a cash on delivery operation with no cash flow in sight.

dg Software. Since I tested everything dg, I have a copy of everything on 8" floppies. I could crash most software in under 5 minutes. Finally the word got out, and the softnerds started checking their software. Then it took 15 minutes to crash.

My favorite dg case was the Mini Bytemaster. It is perhaps the forerunner of laptop computers. Very few of these Mini Bytemasters were made. To get one, you had to know someone (like me). This one has a ham board for CW, RTTY, and SSTV, 64 KB of memory, and a Votrax voice synthesizer. The 5 1/4" single density drive has about 170K capacity.

I have a complete collection of Mini Bytemaster software on 5 1/4" single density disks, plus a considerable amount of special one of a kind software in this 3 ring binder.

The blue 3 ring binder contains everything Mark-8. The early days of microcomputers produced several low circulation newsletters. The second binder has them all. It's fun to look back at what enthusiasts planned to do with their new computer. Also in the box are all the Bytemaster documentation and advertising brochures. In its heyday, dg had its own printing press and photo studio. After one notorious advertisement was printed we had a in house contest to name all the unavailable products!

I used one of these two Teletype 40 chain printers for software development. It was nice to do those long assembly language listings on a 220 line per minute printer. The other printer came from dg software for their order processing. The third TTY40 belonged to dg for their order processing. Last heard, Ron Struthers who worked on the infamous dg dot matrix printers, has this one.

This was one of the projects I should have killed but did not. It was just pure fun. I taught it to speak Latin and English. Will Gasser on a dare taught it to say the Hebrew Blessing of Wine. This is a prototype of the Votrax voice synthesizer. It was carefully potted to avoid algorithm discovery. Because it spoke with a distinctly Swedish accent, the rumor was that it was designed by a Swede from Milwaukee that thought that was how English was spoken. Not true.