IMSAI 8080

IMSAI 8080

The IMSAI 8080 was one of the earliest microcomputers released for the public, and was released towards the end of 1975. It was made and sold by IMS Associates Inc. It was essentially a clone of the earlier released MITS Altair 8800, and is known to most computer historians as the first clone computer, or computer designed specifically to mimic another computer system. The IMSAI 8080 was originally sold as a DIY kit in December of 1975, but eventually sold as already assembled machines. The DIY version sold for a little over $400 at the time, and the assembled units selling for around $600. These prices closely resembled the pricing for the MITS Altair 8800 charged.

The origins of the IMSAI 8080 are quite interesting. IMS Associates Inc actually wanted to purchase several Altair 8800s from the MITS company, but delivery time for these microcomputers would have taken a substantial amount of time, as MITS had originally only planned to sell a couple of hundred and were shocked to immediately get orders numbering in the thousands. IMS decided they would make their own, essentially making their own version of the Altair 8800. The IMSAI 8080 actually had several advantages over the Altair 8800 at first, including easier assembly, more motherboard slots, and a larger power supply. This attracted quite a number of buyers and reviews for the IMSAI 8080 were very positive. In 1976 Altair acknowledged these advantages and released their Altair 8800B which shared many of the same features as the IMSAI 8080.

IMSAI 8080 Inside


The processor for the IMSAI 8080 was the Intel 8080. Initial speed was 2 MHz. Ram started at 256 bytes and up, usually 8K. There was no ROM in the microcomputer, although PROM could be added. Storage was the same as the Altair 8800, with paper tape, cassette tape, and both 5.25″ and 8″ disk drives available as options. Expansion included up to 22 slots, and it used an S-100 bus. Terminal based video and optional video cards were available for the unit. I/O included both serial and Parallel. OS options included CP/M, Northstar DOS, and several others.


The IMSAI 8080 is widely recognized as the first clone computer, and along with the MITS Altair 8800 it was based on, started a new era for microcomputers that would go on to launch the personal computer boom years later. It was one of the first microcomputers to appeal not only to hobbyists and enthusiasts, but also to businesses and people who weren’t necessarily interested in the ins and outs of the machines, but just wanted to own and use one. It may also be the most successful clone, as it sold more than the MITS Altair 8800, and the company actually lasted longer.

Interesting Facts

In the popular 1983 suspense film “WarGames”, Matthew Broderick’s character uses the IMSAI 8080 along with other tools to engage in his hacker activities. For many Americans this was their first exposure to personal use microcomputers. The IMSAI 8080 was also featured in the crime movie “Before The Devil Knows You’re Dead”.

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