The IMSAI 8800
the MITS Altair 8800 was the first practical personal microcomputer and
started the industry, credit for spreading the personal computer
revolution must go to another company_IMS
Associates and its product, the Imsai 8080
computer. While it was not strictly a clone of the Altair, this machine
adopted the bus structure of the Altair and used interchangeable plug-in
circuit boards. This commonality and the availability of the Imsai
assured the dominance of the Altair (S-100) Bus.
Associates was started by William Millard as a computer consulting
company, whose most important consulting project was the development of a
computer system for an automobile dealer. In an effort to reduce costs,
Millard became interested in the new microprocessor chips being
manufactured by Intel, and the possibility of networking many of them into
a powerful computer system he called Hypercube.
the Altair article broke in Popular
Electronics, Millard and his associates tried to order some Altairs
to try out this idea. They immediately ran into two problems. First, MITS
wanted payment in advance, and second, they couldn't promise to deliver
the order for at least 90 days. IMS Associates couldn't get the money
unless they could show their customer that they had a solution to the
problem, and they couldn't wait 90 days. Millard did manage to borrow an
Altair to examine, and he and his associates became convinced that
such a microcomputer represented the best solution to their problem, and
the Altair 8800 was not a commercial piece of equipment by any criteria.
Since the only other choice they had was a much more expensive
minicomputer, with an even longer delivery time, they decided to build a
copy of the Altair. Having made the decision to build their own 8080
computer, IMS Associates decided to correct the obvious defects of the
Altair and build a rugged commercial grade machine.
most glaring defect of the Altair was the location of the expansion
motherboards. MITS used a standard Optima case to house the computer, and
its shape dictated the mounting position of the motherboards. This in turn
caused the board mounting connectors to face the side of the cabinet. As a
result, the connections from the front panel to the motherboard required a
large cable. In addition to making the computer kit harder to build, this
cable was a potential source of trouble over the life of the computer. IMS
Associates designed their own cabinet and made it much deeper than wide.
This allowed the Imsai to be made with the
motherboard perpendicular to the front panel so that the front panel
itself could be plugged into the first connector on the motherboard. This
eliminated the large connecting cable.
front panel of the Altair used small toggle switches to program the
computer in binary machine language (ones and zeros were represented by
switches "on" or "off".) The Imsai
used the same arrangement but replaced the Altair's toggle switches with
heavy commercial-grade "paddle" switches. The plastic switch
"paddles" were colored red or blue. Mounted above the paddle
switches was a colorful plastic panel with the indicator lights showing
through. The name IMSAI 8080 was displayed in the upper right-hand
corner of the panel. To emphasize that this indeed was a commercial-grade
computer, the heavy aluminum cover was painted what was then called
"IBM Blue." In all, the Imsai design
was very impressive and professional.
the Imsai cover was removed, you could see
that the obvious and most impressive difference between the Altair and the
Imsai was the power supply. The Altair used a
power supply rated at 8-amps and constructed of radio grade components.
This was thought to be more than adequate for the original design of the
computer, but not for an expanded system. (MITS later had to upgrade the
power supply to allow for growth.) The Imsai
power supply, on the other hand, came equipped with a massive transformer
and very large computer-grade capacitors. The standard model was rated at
20 amps, and for a small upgrade fee you could get a huge 30-amp supply.
This big power supply could deliver 30 amps at 5 volts and 3 amps at + -
16 volts. Having a large power supply was an advantage because all the
S-100 Bus computers used un-regulated power supplies with power regulators
located on each individual circuit board. One of the most common causes of
failure in S-100 computers was failure of the on-board power regulators.
The use of massive transformers and capacitors provided less electrical
fluctuation and longer life for the power regulators. In addition, larger
power supplies provide a reserve for later expansion.
the computer owner, selection of motherboards for the Imsai
was very important. The standard kit or assembled unit only came with a
6-slot motherboard (2 more than the Altair), but only two connectors. To
expand the system, additional connectors and 4-slot motherboards had to be
added to the computer. Every time you added a connector, you had to
carefully solder 100 connector pins to the board. Whenever a motherboard
section was added, 100 wires had to be added. This required making 200
solder connections, and every solder connection was a potential source of
trouble. The Altair connectors were made with a
different pin spacing than the standard 0.125-inch Texas
Instruments connectors used by Imsai. You
could plug the same circuit board into either type of connector, but the
pins that went into the motherboard were spaced differently. The Imsai
connectors cost from $7 to $10 while the Altair connectors cost $15 each
and were harder to get.
offered a 22-slot motherboard as a $52 option, when you ordered it with
the computer. This was the solution to the motherboard problem. If you
installed with at least 10 connectors, additional soldering seldom had to
be done. Word got around very fast, and almost everybody ordered the Imsai
with 22-slot motherboards and 10 connectors.
the Altair, the Imsai kit only came with the
front panel board and the CPU board. No memory or input/output board was
provided. However, by the time the Imsai was
being shipped, there were several choices of memory boards available. Imsai
made an excellent 4K Static RAM board for $139 in kit form. Processor
Technology had both 4K and 8K Static Ram boards available, and even MITS
had 8K Ram boards and a new 4K Ram board that worked.
really needed about 16K of memory to load BASIC and generate programs with
usable data. You also had to have a working Input/Output (I/O) board to
get things in or out of the computer. I/O boards came in either serial or
parallel form, or both. One of the most popular I/O boards was the 3P+S
from Processor Technology, which had both forms of I/O on one board. Imsai
advertised that they were developing a super I/O board called the Multiple
I/O (MIO) Board, but it never seemed to come out and was referred to as
the "Missing I/O Board."
most important thing that MITS had over Imsai
was the BASIC written by Bill Gates of Microsoft, which was very important
because lack of a good BASIC made operation very difficult.
had little software capability. The only software they supplied Imsai
was a modified version of the Software #1 package, written for Processor
Technology and placed in the public domain. This was delivered on a paper
tape and required 8K of memory. The software consisted of a
executive program, including a text editor and an assembler program for
assembly language. To use it, you had to have a teletype tape reader. The
procedure was not simple. First, you used the computer's front panel
switches to load in a bootstrap loader program, one byte at a time.
the loader was in memory, you could start the tape reader and load the
executive program from the tape. Now, you could use the keyboard on the
teletype to write an assembly program, and the executive program could
assemble it. If that worked, the result was object code for your program,
and it could be stored in RAM memory. If you had enough memory, you could
run your program. Then if everything ran okay, you could store your
program using the punch on the teletype to make a new paper tape. The next
time you wanted to run the program, all you had to do was load the object
code paper tape back into memory and there you were. Simple! This was not
exactly what we today call "user friendly,"
and this is why having a higher level language like BASIC was so
advertised both 4K and 8K BASIC but noted that this was under development
and would be available "real soon now." Imsai
owners did not wait; they got Altair (Microsoft) BASIC by hook or by crook
(mostly by buying it as a group and sharing it among themselves.) Altair
BASIC soon became the standard language for personal computers even before
Microsoft got out of its restrictive agreement with Altair.
spite of its usefulness, the Teletype as an I/O device, printer, and mass
storage device was too expensive, too hard to get, and too hard to use.
The audio cassette interface was a much better choice. Tape recorders were
low in cost and easy to use. The problem was that there was no standard
interface, and tapes made with one interface could not be read by another.
The industry held a meeting in Kansas City to develop a cassette tape
standard, but few adhered to it. Finally, because it worked the best, the Tarbell
Cassette Interface became a de facto standard for S-100 computers,
except for notable exceptions like MITS and Processor Technology's SOL.
Cassette tape took over I/O functions from the paper tape punch and reader
until floppy disks became commonplace. Video terminals and low cost
printers also became available for microcomputers.
had developed the floppy disk to load software, and Altair, Imsai,
and other companies were working to adapt it for use on microcomputers.
The development of floppy disks and disk operating systems, plus cheap RAM
memory, opened up the industry for really useful software, and completed
the transition from hobbyist's toys to really useful computer systems.
of component board interchangeability, almost no one ran a complete Imsai
Computer System. The computer itself might be an Imsai
with its 8080 CPU, but even that was likely to be a Z80 CPU from TDL, or Cromemco.
The memory could come from any of two dozen manufacturers. Seals Memory
were popular 8K boards as were Vector Graphic, IMS (not related to Imsai),
and Processor Technology. In 16K memory boards, Cromemco
and Processor Technology were well thought of, as were TDL, Seals, IMS,
and a few others. The I/O board was most likely to be a 3P+S from
Processor Technology although George Morrow made a popular one and some
people liked the Vector Graphic. The computer terminal was likely to be a
Adam 3A or a Hazeltine 1500. Many users saved
money, and in place of a separate video terminal, installed a Processor
Technology Video Display Module (VDM) and a keyboard. With this
combination, they used the computer itself as a terminal.
data and program storage, they often used the Tarbell
Cassette Interface before the advent of the floppy disk drive. Imsai's
first attempt at a "smart" floppy disk drive was a total
failure. Later, various disk drives from MITS, Pertec
Persi, North Star, George Morrow, Micromation,
and Cromemco were installed in Imsai
computers. Imsai finally did manage to come
out with their own working floppy disk unit. At
first, all the floppy disks were 8-inch units and were very expensive.
When the 5 1/4-inch floppy disk drives came out, many computer owners who
had not been able to afford disk drives purchased them from Pertec,
North Star, and other companies.
very important thing that Imsai did to advance
the use of floppy disks was to license the best disk operating system,
later to be known as CP/M. In fact, it was money from the Imsai
license that encouraged Gary Killdal to form
Digital Research Incorporated and to get into the CP/M operating system
Imsai never became a successful systems house
as did Cromemco and others, the Imsai
8080 with its massive power supply and 22-slot chassis was a foundation
for almost any 8080 or Z-80 system you could think of. Even Alpha Micro
Systems used the Imsai for its first 16-bit
IMS Associates to IMSAI Incorporated
company that developed the Imsai was very
different from the company which invented the MITS Altair. Ed Roberts of
MITS was a technical person who was propelled into the leadership of a
rapidly expanding computer company. Bill Millard, on the other hand, was
an entrepreneur who envisioned the growth of his company into a vast
computer utility. He was a believer in the self-improvement techniques
developed by Werner Erhard, called "EST," which he attempted to
apply to all situations. EST convinced him that once he had made up his
mind to do something it was as good as done. He surrounded himself with
people who had "taken the training," and this was a big factor
in the accomplishment of bringing the Imsai to
market in record time. It was also a factor in the failure to test
equipment before releasing it to the market, and the inability to see
changes in the market as the technology advanced. Fortunately for Imsai,
in addition to Millard and his "ESTheads"
the company also had the services of some of the best sales and marketing
executives in the industry, including Ed Faber, who built both Imsai
and Computerland, and Seymour Rubenstein, who
founded MicroPro the owner of WordStar
said that MITS was an engineering company who did not know how to build
and market their products. Imsai, on the other
hand, was a marketing company who developed one brilliant product and
overexploited it. From the Imsai 8080 on, they
never knew the difference between a prototype and a production model, and
never really had another successful computer.
Life and Death of Imsai
When the Imsai
8080 was in development at IMS Associates, it looked like the company
would run out of money before the computer was completed. As a last
resort, Millard placed an ad in Popular
Electronics Magazine, describing the computer and offering it for sale as
a kit. The ploy worked beyond their wildest dreams. The computer hunger,
fed by the Altair articles and the inability of MITS to deliver, impelled
people to send in checks for the Imsai 8080
merely from the description in the small ads. Millard used some of the
money to prepare a professional ad campaign and place ads in Byte and all
the other computer magazines now appearing. The stream of checks grew to a
flood and people started to inquire about becoming dealers.
owner of the Computer Mart of New York, which was about to open, I was one
of the first people to contact IMS Associates. They were very interested
in selling in volume to dealers, but they had priced the kits at $439, a
price too low to provide for dealer discounts. Quickly they raised the
price to $499 and allowed a discount of only 15% for orders of 10 or more
computers. This was still not enough margin to
allow a dealer to make a profit after paying his overhead, considering the
small quantity we could sell. Then Ed Faber came up with a scheme that
benefited both the company and the dealers. He proposed that if we dealers
could pay for the computers in advance, we could get another 5% and IMS
would pay the shipping cost. For me that was the clincher; I sent off my
check and prayed that IMS Associates would make delivery on time. Little
did I know that I would get priority because Millard and Faber wanted
their computers on sale in New York where they were trying to raise
in San Leandro, the people in IMS Associates
went to work to build their first 50 kits to make the initial shipments.
By December 1975, they had shipped the first lot and were at work
on the second batch of 250 kits. Ten of these were mine, and
never had I sweated out anything more than the arrival of those computers.
I had exactly one complete computer, one partial kit for the Sphere
computer, ten video monitors, one teletype, a
lot of books, assorted parts, chips, and connectors to open a computer
store with. We hoped to open March 1, 1976, but in the middle of January
five of my Imsais arrived and we couldn't wait
to open. Not convinced that we would ever make it, I had been looking for
work and had contracted to write a manual for the Warner Communications
Timesharing Service. We actually opened on New York's Fifth Avenue in back
of Polk's Hobby Department Store in February 1976 and started immediately
quickly saw the potential of the computer stores and took IMS Associates
(now called Imsai ) out of the direct sales
business. Instead, he developed a plan where a dealer had to commit to
only 25 computers a year and put up a deposit of $2,500. The discount was
put at 25%, and Imsai would ship on a C.O.D.
basis rather than requiring cash in advance. For us established dealers,
it was a great help. However, under this plan dealers sprouted all over
the place, in garages, lofts, and hardware stores. In addition, the mail
order discount dealers appeared, and people started to bring in kits they
had bought by mail but couldn't put together.
first big computer show held in Atlantic City, New Jersey, on the weekend
of August 27, 1976, Imsai was not an exhibitor
although MITS and every other company was
showing their products. However Ed Faber walked through the show like a
king. The truth was that there more Imsai
computers than any other make. Every retailer had Imsais,
as well as people selling boards and peripherals. In addition there were
heaps of Imsais piled up and marked with
bargain prices for sale at the show. Although MITS was the biggest
exhibitor at the show and they introduced the new Altair B model, Imsai
got the greatest attention
I was one of the few dealers not showing Imsai
computers. Instead I had a brand new computer made on a single board. It
did not need a teletype because it had its own video output to a TV set.
It had a very fast cassette interface for data storage, and it had its own
version of BASIC that came with the computer. It was called The Apple and
it was being shown in my booth by two young men from California, Steve
Jobs and Steve Wozniak. The Apple proved to be one of the hits of the
show. In addition to the Apple, the show introduced the new Processor
Technology SOL, the new Cromemco, and the TDL
Z-80 CPU board for the S-100 Bus.
we did not realize it at this show, the handwriting was on the wall for
the Imsai 8080 as well as the Altair. The new
generation of computers was already here, and within a year the SOL became
my biggest seller, followed by the Apple II a year later.
as a company tried to introduce several new products as an upgrade to the
8080. One was the "smart disk drive mentioned previously. It was a
single sided 8-inch floppy disk drive originally set for introduction in
1976. The unit was released and shipped before it was completely tested,
and it proved to have all kinds of design problems. When it did work for
any length of time, it grew very hot and generated heat to distort the
diskettes. It quickly became known as "The Imsai
Pizza Oven" and was quickly withdrawn from the market. The next
version took over a year to complete, although it was offered in the Imsai
product launched with an intensive advertising campaign was the Imsai
8048 Control Computer. This was a single board computer designed to
control all kinds of electrical devices. The 8048 computer worked, but
priced at $200 to $400 it found no market. Other devices such as the
Commodore KIM-1 were much more versatile and cost only half as much.
addition to the declining market for Imsai
8080 computers, and the lack of follow-on products, there were other
problems in the Imsai Corporation. Bill
Millard had decided that his future was to be in selling computers rather
than manufacturing them. A man named John Martin had brought him the idea
of setting up a franchise computer business to be called Computer Shack.
Martin had actually copied the idea from Paul Terral's
Byte Shops, but had added some ideas from his experience in the franchise
muffler business. Millard incorporated The Computer Shack franchise
business, put Ed Faber in charge, and started to sell franchises.
business caught the crest of the wave of interest in computer stores and
quickly became a major force in the industry. The only setback was caused
by Radio Shack, which caused a name change to Computerland.
The Computerland stores carried Imsai
computers but they also sold Apple, North Star, and Cromemco.
In fact, the Imsai 8080 became one of the less
popular computers in the stores.
to dominate both the retail franchise and manufacturing ends of the
computer business, Millard forced his Imsai
division to produce a desk top business computer called the VDP-80. This
was an all-in-one machine with the video monitor, keyboard, disk drives,
and computer, all in one cabinet. Millard had the cabinet built in Europe
with an eye to exterior design and no consideration given to the
requirements for the internal components. The new machine was plagued with
problems and in addition had an unproven dual floppy disk drive made by Persci.
This drive was almost impossible to keep in alignment under the most
favorable conditions. In the furnace inside the VDP-80, it refused to run
properly. Although intensive advertising sold this computer, Imsai
could not afford to keep up their warranty. There was a quick re-design
installing 5 1/4-inch drives to replace the 8-inch Perscis
and changing the name to VDP-40. However, the damage had been done. The
Computer Mart of New York refused to sell the VDP-80 and gave up the Imsai
dealership, which had become unimportant anyway.
had stripped Imsai of all its resources and
put them into Computerland. Bankruptcy quickly
followed for Imsai. While Computerland
went on to become the most important retailer of Apple and IBM PCs, the
foundation crumbled and Imsai disappeared.
Many of the assets of Imsai, including the
rights to the name, were bought by Fisher-Fitas,
a former sub-contractor to Imsai. They
continued the manufacture of the original rugged 8080 machines until the
parts ran out and then the Imsai 8080 became
stores prospered as the primary retailer of IBM computers but, when IBM
abandoned the ISA bus and the clone business started, they fell on hard
times. The franchisers joined in a bitter legal battle with Millard and
became independent of his control.