After seeing the instant success of the MITS ALTAIR 8800 computer, the first "home computer" ever made, others soon tried their luck in this new business space. One of the first to do so was Bill Millard who founded IMS Associates.
The computer they designed, the IMSAI 8080, was very similar to the Altair 8800 and was designed to run the same software. However, it was a much better design, with a higher specification power supply, an anodized aluminum chassis, 22 slots on the S-100 bus, and a great front panel design.
The IMSAI 8080 aimed to take advantage of the Altair's popularity, the inability of MITS to meet a growing demand for the product, and the need to improve on some of the internal components. Like the Altair, the IMSAI came either in kit form, or preassembled at the factory.
At the production starting, the IMSAI was shipped deliberately missing many parts in the kit version, because the company hadn't received them yet. But since IMSAI promised delivery by a certain date, they shipped them anyway!
Like the Altair system, there were no keyboard but a front panel and switches used to program the system. The LED's blinked, depending of the values found on the address and data buses. One could manually stop the CPU, single step the CPU, and read and write to memory locations.
In the end, the IMSAI outlasted the Altair by several years. Owners were delighted to see it featured in the 1984 movie "War Games", with Matthew Broderick and Ally Sheedy. Through the years, it has remained a much-beloved design amongst vintage computer collectors, and newly-manufactured parts and documentation are still available! (see Web links)
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I was lucky enough to buy the IMSAI 8080C computer at a computer business that had an auction after the owner passed away for $14. ! It works great but I couldn''t bid on the two 8"floppy drives because the $14. was all I had! I begged the auctioneer afterwards for the drives as they didn''t sell, but he wouldn''t relent... My unit needs 3 switch covers(orange/blue) as I accidentally knocked them off... I have them somewhere. The computer is immaculate and works as if new,(love the robustness of older technology electronics). One big TO-3 voltage regulator(5V?) on the back wall on a aluminum 90 degree fin in front of the fan and two big capacitors(electrolytic) in the front in the voltage supply area on the right, walled off by aluminum shield from the S-100 bus slots on the left. The CPU is white w/gold cap. Such a joy to see it operate on the front panel as I load address and data registers(8 bit)using the switches in single step load/review mode. Then I flip then switch for Run and toggle the start switch and watch the digital light show as it computes, branches, adds and moves REAL Binary Data around before I hit the start/stop toggle switch or it reaches a halt in the program. I need to make a digital video of it in action someday. It is still a joy to operate, setup, run and observe the data in red Light Emitting Diodes(LEDs). This was one of the first times we could SEE our data bits and computing in action.
I was a programmer in the Air Force on 64-bit machines in the early 70''s... COBOL, PL/1, RPG, FORTRAN and assembly.
This machine is a museum piece that STILLl functions as it was designed. I had a few Timex Sinclair''s as well. Also great inexpensive machines for their day. Clive Sinclair was a mathmatician and it is reflected in the tight byte codes of his BASIC language computers for the masses. They are great as 8/16 bit scientific BASIC computers, not just for gaming, which is fun, and drove the computing industry to where it is today.
Steve Ingham 9-19-2018
Wednesday 19th September 2018
GOplayer (USA)
I bought my IMSAI 8080 as a kit back in 1976. By 1979 I had it feeding a Heathkit H9 terminal and was running Northstar Basic. Writing and running Basic Code LOL. Everything is still downstairs in my basement in boxes, although I havent fired them up since 1983.
Saturday 12th November 2022
Lorno (Calgary, Canada)
I used a couple of IMSAI 8080''s at NASA in the early 1980''s. Each had a Z80 4MHz CPU and 64KB of RAM. For storage each had a dual set of 8-inch floppy drives. Each also had a 5MB hard drive but were never used much because they were not very reliable and eventually failed.
Thursday 29th September 2011
Edward Kenny (Huntsville, AL USA)
NAME
8080
MANUFACTURER
IMSAI
TYPE
Home Computer
ORIGIN
U.S.A.
YEAR
Start of 1976
BUILT IN LANGUAGE
None
KEYBOARD
None, front panel switches are used to program the system
CPU
Intel 8080A (rarely 8080)
SPEED
2 MHz (each instruction takes 4 clock cycles)
RAM
256 bytes
ROM
Unknown
TEXT MODES
Depending on the video terminal used (optional 64 x 12 card)
