Processor Technology SOL
defects of the original Altair 8800 computer helped create the supporting
industry. Even after the purchaser laboriously soldered together all its
parts and managed to get it working, the original Altair 8800 computer was
little more than a box full of promises. It consisted of a front panel
full of little switches and lights, and a metal cabinet containing a power
supply. The entire computer portion was one CPU circuit board with the
microprocessor chip and a memory of only 256 bytes (expandable to 1,024
Gary Ingram and Bob Marsh, a couple of friends from Berkeley, California,
the Altair's faults were seen as their opportunity. Marsh, a member of the
Homebrew Computer Club, listened to complaints at each of the club
meetings and determined that one of the major problems with the Altair was
the small amount of memory provided with the computer kit. The Altair's
design did provide for plugging in additional memory boards, and both 1K
and 2K Static Memory Boards and a 4K Dynamic Memory Board were offered by
MITS. However, the 4K memory board was considered unreliable.
and Ingram decided to form a company, Processor Technology Incorporated,
to produce improvements for the Altair.
two partners were completely different. Marsh, a small good-looking man
with dark hair and a thick mustache, had an outgoing personality and a
good sense of humor. Gary Ingram was a long haired, reclusive ascetic. He
seldom had anything to say to outsiders. Both
were deeply involved with electronics. Though Marsh had dropped out of
engineering school, he worked on the fringes of the industry. Ingram was
employed as an engineer. The partners developed a wish-list of improved
boards for the Altair.
their ideas as already-completed products, they composed a magazine ad and
a hand-out flier, hoping to generate funds for their enterprise. This was
a common practice in those days. People read ads and would send money to
buy "vaporware," products that were announced and sounded good,
but would only be available "real soon now." In the case of
Processor Technology, their ads reaped a harvest of checks, and the
partners were able to rent Lee Felsenstien's
first product Bob Marsh worked on was a 4K (4,096 bytes) static memory
board. He knew 4K was needed to run the smallest version of Altair Basic,
yet the most glaring defect in the Altair was the lack of reliable 4K RAM
are two kinds of memory chips used in constructing computer memories. The
Read Only Memory (ROM) chip, once programmed, retains its information even
though you turn off the power. However, since its memory can not easily be
re-programmed, the ROM chip is only used for information that does not
Access Memory (RAM), the second type of memory chip, can easily be
re-programmed, and so it is the working memory of the computer. There are
two types of RAM memory chips. The most common, Dynamic Memory (DRAM)
needs periodically to be given a pulse of electricity (refresh) to keep
its memory alive. The alternate choice is Static Memory (SRAM), which
consumes more power, but will retain its information without refresh as
long as it is connected to a power source. Both DRAM and SRAM will lose
information once the power is turned off.
had intended to make memory expansion its first priority, but the
expensive 4K dynamic memory board it created did not work well. The Altair
board obtained its essential refresh pulse from the 8080 microprocessor
chip by a process called "cycle stealing." The problem with this
technique is that sometimes the computer chip is off doing something at a
time when the memory needs to be refreshed. If this happens, the memory
"forgets," and data is completely lost! To make "cycle
stealing" work at all, precise timing is required.
problems in the Altair 4K board were what made it defective. Bob Marsh
designed the very reliable Processor Technology 4KRA Memory using static
memory (SRAM) chips. It had 4,096 (4K) bytes of memory, but if you didn't
need that huge amount you could buy it with only 2K, and later add the
rest. The 4KRA was priced at $218 in kit form, or $280 assembled, while
the defective MITS board cost $264 in kit form and $380 assembled. When
8080 computer users read the ads for the 4KRA, they flooded Processor
Technology with paid-in-advance orders.
instant success of Processor Technology's 4KRA was the catalyst that
launched the company into business. Bob Marsh and Gary Ingram moved from
their garage workshop into a much larger industrial facility in
Tech's Altair Mother Board
the company's great success with the 4KRA memory, Marsh turned his
attention to another acute but much simpler problem with the Altair. It
badly needed a better motherboard, and MITS was not going to provide one.
When you bought the computer kit, MITS only supplied a four-slot
motherboard and one connector for each plug-in board ordered. If you
originally bought the kit with only the Central Processing Unit (CPU)
card, you only had one installed connector. When you wanted to put in a
memory board, you had to disassemble the computer to solder in the 100
pins for the next connector. Most owners only went through that once. They
got smart and soldered in all the remaining connectors at one time. If you
wanted to expand your computer with additional plug-in
boards, you had to solder in additional four-slot motherboards and
really had to be a dedicated hobbyist to go though that kind of torture.
Processor Technology designed an 18-slot motherboard and sold it for only
$35. You could add Altair's full compliment of 18 connectors (at a cost of
$15 each) all at one time. Word of this improvement quickly spread among
Altair owners, and they bought all the boards Processor Technology could
2K ROM Board
Technology offered another product they thought was needed for the Altair
or Imsai, a 2K ROM board. Loaded with
programmed Electrically Programmed read-only Memory (EPROM) chips, this
board allowed the user to start his computer without flipping countless
front panel switches. The board was not much of a success. It came without
the EPROMS, which were difficult to buy and once bought were beyond the
programming ability of most computer hobbyists. In addition, the computer
hobbyists liked to flip the front panel switches. It was part of the
mystique of the computer they were unwilling to share with the casual
Technology proposed to supply its customers with "almost free
software." For only $15, it made Software Package #1 available,
containing an assembler, a text editor, and the system executive programs.
The utility programs in this package made it possible for the hobbyists to
develop applications using the additional memory now available. Processor
Tech also promised a low cost version of BASIC, a promise that caused them
a lot of trouble and was not kept for about a year.
I expressed interest in becoming a Processor Technology dealer, Les called
Bob Marsh from my store and arranged for my dealership. As with IMSAI, my
main supplier, the financial arrangements were simple. My order was paid
for with cash-in-advance, so the company could use my money to buy the
parts to fill the order. I got most of the advanced cash from customers.
They were so anxious to get the boards, they
were willing to pay at least 2/3 of the price up front just to be placed
on my delivery list. Of course, if the wait was too long, I had to refund
the money. But often, no matter how long the wait, customers chose to
leave their deposits rather than take a chance on being dropped from the
best part of becoming a Processor Technology dealer was that it greatly
expanded my customer base. Ed Roberts, head of MITS, would not let his
dealers sell any products that competed with Altair. My philosophy was
directly opposite. My store was the very first to sell more than one brand
of computer, and my policy was to carry all kinds of computers and
accessories. Since I could not sell Altairs,
the people who owned them never had occasion to come into my store.
However, with the Processor Technology line Altair owners flocked in to
shop for the products they read about in the magazines. They bought
Processor Tech boards from me as well as chips, connectors, software,
books, and magazines.
sorely-needed new Processor Tech products revealed to me by Les Solomon
were an input/output board and a Video Display Module. Until this time the
difficult job of getting information into, or out of, the microcomputers
required separate parallel and serial interface boards.
that time, the main input/output device used with big computers,
minicomputers, and microcomputers was the Teletyper.
This wonderful but noisy machine was both a keyboard-input terminal and an
output printer. In addition, many Teletyper
models included a paper tape punch which could be used as the computer's
to a Teletyper, your computer could
"dump" the program or data in its memory by punching a pattern
of holes into a paper tape. These paper punches could also duplicate their
tapes. As many copies as required could be made, and the paper tape could
then be rolled or folded up and stored in a drawer. In the early days,
punched paper tapes became the principal method of distributing software,
mainly because there was no standard for cassette tape.
the microcomputer user, the main problem with the Teletyper
was its cost. The Teletype Corporation sold only to large companies and
then only on a yearly contract. New machines cost about $1,800 (three
times as much as the microcomputers) and were very hard to get. On the
re-sale (gray) market, "used" machines (really, new ones) were
sold for as much as $2,500 and re-built ones for about $1,200. Computer
hobbyists tried to find old, obsolete models to repair and put back into
service, but they were scarce.
if you had a Teletyper, you still needed a
serial interface board to connect it to the computer. The 3P+S Interface
board from Processor Technology had three parallel ports (3P) for
connection of various devices such as keyboards, printers, and plotting
boards. The 3P+S board also had a serial port (+S) for connection of any
kind of Teletyper, no matter how old it was.
This was possible because the 3P+S had hundreds of options, which you
could select by installing various jumper wire combinations. No matter
what printers, terminals or other I/O devices you added in the future, you
would never outgrow the 3P+S.
an effort to provide machines for Altair users, MITS made a deal with
Teletype Corporation. For $1,500, MITS sold a brand new Teletyper
machine that would only work with their Altair I/O board. Within a few
months, the hardware hackers found a way to interface the Altair/ Teletyper
machine with a 3P+S board. The information quickly became available to all
users through the magazines and computer clubs, rapid conduits for all new
breakthrough information. Selling for only $125 in kit form, the 3P+S
became Processor Technology's best seller.
VDM-1 Video Display Module
1975, using a video terminal instead of a printing terminal for computers
was a relatively new idea. The video terminals were sometimes called
"glass teletypes." They were expensive. The price of a video
terminal was many times the cost of a personal computer, so they were only
used for large computers
September of 1973, two years before the Altair appeared, Radio Electronics
Magazine had published an article, "The TV Typewriter" by Don
Lancaster, describing how to build a crude video device. This device used
a TV screen to display the characters which had been typed on a keyboard.
working for Processor Technology, Lee Felsenstein
had been attempting to build a video-operated "Tom Swift
Terminal." Therefore, Marsh and Ingram chose Lee as the person to
build the plug-in video terminal board needed by the Altair.
Processor Technology VDM-1, as it was called, was advertised for sale in
the first issue of Byte in September of 1975. Delivery was promised 3
weeks after receipt of order. Processor Technology, like all the early
computer manufacturers, underestimated the development time required for a
proposed product. The VDM-1 was not actually available until the fall of
1976, and even then delivery might take up to 60 days after order.
the VDM-1 finally was delivered, it did everything promised. You could
connect a keyboard to the computer through the 3P+S Board, plug-in your
VDM-1, connect it to a video monitor, and your computer became its own
video terminal. The VDM-1 also ran one of the first action video games.
Developed by Steve Dompier, Target shot arrows
at targets moving across the screen.
video board was almost too good to be true, with only a few minor faults.
A real video display terminal usually had 80 characters displayed across
the screen and could show 24 lines of text. The VDM could display only 64
characters on each line, and there were only 16 lines of text. A real
video display terminal was made, with special cathode ray tubes (CRT's)
and video circuits designed for that specific purpose. Such CRTs were not
available for use with the VDM-1. You had to use either video monitors
designed for closed circuit television, or converted TV sets. In TV, the
picture is "painted" on the face of the tube by a stream of
electrons. It "paints" (scans) one line at a time. At the end of
the line, the electron stream is blanked out and is returned to the next
line. Then it scans across the tube again. This TV scan rate, which
permitted only time enough to display 64 characters by 16 lines, was used
as the basis for the VDM-1 design. Since typing margins are usually set at
characters from the edge of
the paper, 64 characters proved to be satisfactory for word processing.
The VDM-1 was such a wonderful board that users forgot its shortcomings.
It became another best seller for Processor Technology.
Time of The SOL
VDM-1 completed the full line of expansion boards for the Altair/Imsai
computers. Processor Technology now proposed to write an article
describing how to build a video terminal for the Altair. Popular
Electronics Magazine agreed to publish the article and show the completed
terminal on the cover, provided it was ready for photography within 30
days. Bob Marsh hoped a cover story would assure immediate success for the
new product, so he challenged Lee Felsenstein
to undertake the task. Using the same circuits Processor Tech perfected
for their earlier boards, Lee set to work to meet the deadline. His final
design went further than the requirements for a video terminal. He
developed a complete new computer. This was a different kind of a
computer, one designed not for hobbyists and hackers but for business
people who needed useful applications. This was to be a machine not
relegated to a workroom or the basement, but a computer that could proudly
claim a place in a living room or a private office. The new machine would
look somewhat like a modern blue typewriter with handsome walnut side
panels and an excellent keyboard.
friend of Bob Marsh could supply the walnut side panels for the case, if
the computer was designed low enough to fit them. The height problem was
solved by mounting the expansion boards horizontally rather than
vertically. With only room in the case for five boards, most of the
computer functions, including the CPU, video, I/O ports, and cassette
interface, were mounted on a single large PC board positioned on the
bottom of the computer.
design included a completely new idea, the "personality module."
This was a ROM containing various types of system software which changed
the capability of the computer. It could have a standard operating system,
an intelligent text editing system, or a special operating system designed
for a specific job. To effect a change in personality, all you had to do
was plug-in the appropriate module.
stripped-down terminal version Lee designed for the magazine article had a
personality module, but only had limited RAM memory. It was still more
intelligent than most "glass teletypes," so it was called The
SOL Intelligent Terminal.
full version was to come in two styles. The less expensive one had a
simple keyboard and only one slot for expansion. It was called The SOL-10,
and very few were ever built. The second model was a complete computer
with an excellent keyboard and a card cage with five slots. It was called
The SOL-20, and provided enough memory for general computer applications.
the prototype was complete, the Processor Technology crew headed for
Bob Marsh revealed the name to me, I called Les and joked, "They're
naming the new machine after you_The LES
was flattered by the honor in spite of the fact that when Bob Marsh and
Lee Felsenstein arrived with the computer, it
did not work. It took two days of intensive troubleshooting in Les's
basement workshop to bring the SOL to life.
article in Popular Electronics offered a kit version at a very low price
and free schematics to all who asked. Processor Technology, deluged with
orders, took almost a year to fill them. The SOL-20, the full working
computer, was introduced at the Personal Computing '76 show in
store was selected to be one of the first dealerships to get the SOL. We
were a large, well-established
immediately called the factory for repair instructions.
you wait a few days?" Bob Marsh asked me.
I answered. "What's going to happen? Magic?"
days later, Lee Felsenstein walked into the
Computer Mart and asked, "Where are those dead computers?"
fully operative SOL was important enough to put the designer on a plane
for the first service call. From that time on, all computers were
carefully tested before shipment. We never again received a SOL that did
not work right out of the box. In fact, the SOL became known as the most
reliable machine on the market. By 1977, SOL was the dominant personal
computer in the industry and was the principal product in my store.
the spring of 1977, Processor Technology called a "mandatory"
dealer's meeting at its headquarters in Emeryville, and I traveled to
at the meeting, I received several urgent calls from Steve Jobs asking me
to meet him in his garage "factory." He was so insistent that I
took time out to meet him and Steve Wozniak. What happened there is the
subject of another chapter, but two years from that meeting Apple Computer
had replaced Processor Technology as leaders of the industry.
the Processor Technology meeting, Bob Marsh described the company's plans
to introduce the Diablo disk system. This disk
system, which was to sell for $1,200, was exactly what the dealers needed.
The SOL computer was selling to business people more than home users, and
cassettes were not appropriate for storing business programs and data.
Gary Ingram made one of his rare appearances, and demonstrated the disk
system and the PTDOS operating system. The dealers were also promised
larger memory boards and a new color video board.
was so good that Processor Technology announced it would no longer require
cash in advance. Qualified dealers could now place orders and pay COD.
Thirty-day credit terms were promised in the near future. Dealers had to
submit an order every three months, and for larger orders there would be
an increasing scale of discounts. We all left Emeryville with a feeling of
confidence that both Processor Technology and our dealerships were well on
the road to legitimacy, leaving behind the "hobbyists" stigma
and emerging as a real computer business.
I returned to
the picture wasn't quite as rosy as it seemed for Processor Technology.
The Diablo Company, whose main business was daisy wheel printers, was
purchased by Xerox Corporation, and the development of Diablo's floppy
disk drives was stopped. Most of Processor Technology's work on the floppy
disk drive system was lost. They were back to square one using cassette
and Ingram's answer to this problem was to adopt a new disk drive just
coming on the market, the Persci 270. A new
and untried device, it drove two 8-inch floppy disks with one motor. The
basic idea was to obtain twice the disk storage at less than the price of
two drives. The new Processor Technology floppy disk system, called
Helios, consisted of a cabinet containing the Persci
270 (with two drives in one assembly), the power supply and cables. The
PTDOS disk operating system was included. The cost, $1,895, was later
raised to $2,300.
a while Processor Technology continued to grow, and the dealers prospered.
Then Radio Shack came out with its TRS-80 Model I at half the price of the
SOL. They eventually developed a disk drive and the TRSDOS operating
system. The Apple II appeared and quickly became very popular. The Apple
II sold for much less than the SOL, could do graphics in color, and had an
ever growing library of software. Its drawbacks were a 40-column screen
and the lack of upper/lower case characters. In spite of these drawbacks,
when Steve Wozniak developed an inexpensive and reliable floppy disk drive
for the Apple II, it soon outsold the SOL.
Processor Technology, the partners were mesmerized by the success of their
company. They became aloof, less available to the dealers, and appeared
not to be interested in their problems. Lee Felsenstein
urged them to improve their products, but, except for larger memory
boards, no new products were under development, and no attempt was made to
upgrade the SOL to keep it ahead of its rivals. The promised color video
board was never delivered and neither was the promised improved BASIC.
Though Chuck Grant and Mark Greenberg, owners of North Star Computers, had
been under contract to Processor Technology to develop a version of BASIC
for the SOL, North Star, claiming that their agreement was non-exclusive,
sold it to other computer manufacturers. Processor Technology was under
the impression that the BASIC was exclusively theirs, sued, and lost the
case after a long litigation that hurt both companies.
spite of the growing problems, Processor Technology moved south to a much
larger plant in
North Star developed a new, low-cost, mini-floppy disk drive system that
would work with the SOL. Coming
with its own operating system, the disk cost less than half the price of
he started, Larry did not realize he had undertaken a tremendous task. He
was a wealthy young man who hung out first at my computer store, and then
at Bob Radcliffe's Hoboken Computer Works. Radcliffe,
a former Bell Labs engineer, urged Larry to try this difficult job as a
way of learning about programming and computer hardware at the same time.
As Larry progressed with Bob's help, it became apparent that the job would
sell the product, Larry first sold "program patches" to CP/M
owners that allowed them to run their CP/M software on the North Star 5
1/2" drives. Then, at the suggestion of Tony Gold, who ran the CP/M
Users Group, Tony and Larry formed a business called Lifeboat Associates
because they were "all in the same boat." The partners licensed
CP/M from Digital Research Incorporated and produced a new North Star 5
1/2" Drive version of CP/M. If Processor Technology had adopted the
North Star floppy disk system, it might have avoided additional trouble.
However, because of the past legal problems, the partners refused to even
consider it. They kept trying to sell the Helios disk system to their
dealers. Problems with Helios started to surface almost at once. Although
much faster than most of the other 8-inch disk drives being sold, the Persci
270 was very sensitive, difficult to keep in alignment, and if moved,
might lose alignment and stop working. Unfortunately, these problems only
surfaced after Processor Technology spent thousands on development and
manufacture, and had shipped the Helios to several dealers. It was too
late to switch to another drive.
addition, many people, including the dealers, urged Marsh and Ingram to
abandon PTDOS, their proprietary operating system, and adopt CP/M. The
partners refused to listen, certain that their system would be much
their pleas and recommendations went unheeded, the dealers became less and
less interested in the Helios. They could sell the North Star disk drives
and ignore the undependable, expensive Helios. For the next year most of
the dealers sold SOL computers with North Star disk drives and CP/M from
Lifeboat. This made business applications possible. If
you included a daisy wheel printer and either WordStar or Michael Shrayer's
Electric Pencil, the SOL became an efficient word processing system that
only cost $3,500. In those days, an equivalent dedicated word
processing system cost $10,000. Soon other disk drive systems made by
George Morrow, Micromation and Micropolis
came on the market and could also be used with the SOL and CP/M.
SOL dealers who ignored Processor Tech's Helios disk and its oddball
software prospered, but dealers who sold the Helios found themselves in
trouble because of constant failures. In my case, one of the few Helios I
sold resulted in a lawsuit by my customer against Processor Technology,
one of many such cases throughout the country. Until suit was brought,
Helios customers could not even get the principals at Processor Tech to
discuss the problem. Marsh and Ingram would listen to no one.
if the problems with the Helios drives were not bad enough, Processor
Technology finally came out with a new line of dynamic 32K and 64K memory
boards. These boards used new dynamic memory chips rather than the static
memory used in the original Processor Technology memory boards. The
required refresh cycles for the dynamic memory chips were generated on the
board itself. This procedure supposedly made them "safe" from
the problems associated with the original "cycle stealing"
dynamic memory boards. But all at once, all over the country, these new
memory boards began to fail. At first, Processor Tech replaced the
defective boards, but the problem soon became overwhelming. When dealers
sent in defective memory boards for replacement, none were returned.
with the dealers became more strained. It became harder and harder to
communicate problems to the partners, yet people on the lower level were
not given the power to make decisions.
keep my dealership, Processor Technology required that I send in an order
every three months, but, since I (and other dealers) were
selling more and more Apple II's and less SOLs,
our inventory of SOL boards and computers grew until it reached almost
$100,000. I became very concerned and tried to talk to the company about
my problem. I knew I couldn't afford to buy any more, and I wanted to run
a sale to convert this excess inventory into much-needed cash. When the
ordering period came, I declined to order anything, and Processor Tech
pulled my dealership. In answer to this, I prepared an ad for Byte and
several other magazines saying "SO LONG SOL" and announcing a
clearance sale at 50% off. When Processor Technology heard about it, the
partners called and begged me to take back my dealership.
Ingram himself said, "It all was a terrible mistake. Please don't
drop the line."
would help me reduce my inventory by selling it to other dealers. Because
of our close relationship in the past, I agreed and canceled the ads. But
my problems were only typical of the trouble at Processor Technology. The
accumulated mistakes and the unresolved problems, compounded by the
inaccessibility of the owners, proved to be overwhelming. On
Felsenstein went on to design the Osborne 1
Computer, Bob Marsh went into business building mini floppy disk drives
for the Osborne Computers, and Gary Ingram completely disappeared from the
industry. But the thousands of SOL computers did not disappear; they
survived and were used for years by their owners until they could not be
maintained any longer.