The IMSAI 8080 was an early microcomputer begun in late 1975, based on the Intel 8080 and later 8085 and the S-100 bus. It was compatible with its main competitor, the earlier MITS Altair 8800, by which it was inspired. The IMSAI is largely thought of as the first "clone" computer. The IMSAI machine used a highly modified version of the CP/M operating system called IMDOS. It was designed, made and sold by IMS Associates, Inc. (later renamed IMSAI Manufacturing Corp). In total, between 17,000 and 20,000 units were produced from 1975 until 1978.

History 
In May 1972, William Millard began business as IMS Associates (IMS) in the area of computer consultancy and engineering, using his home as an office. By 1973, Millard began IMS Associates, Inc. Millard soon found capital for his business, and received several contracts, all for software.

In 1974, IMS was contacted by a client which wanted a "workstation system" that could do jobs for any General Motors new-car dealership. IMS planned a system including a terminal, small computer, printer, and special software. Five of these work stations were to have common access to a hard disk, which would be controlled by a small computer. Eventually product development was stopped. Millard and his chief engineer Joe Killian turned to the microprocessor. Intel had announced the 8080 chip, and compared to the 4004 to which IMS Associates had first used, the 8080 looked like a better idea. Full scale development of the IMSAI 8080 was begun, and by October 1975 an advertisement was placed in the magazine Popular Electronics, receiving positive reactions.

IMS shipped the first IMSAI 8080 kits on December 16 1975. In 1976, IMS was renamed to IMSAI Manufacturing Corporation because by then they were a manufacturing company, not a consultancy one. By October 1979 the IMSAI corporation had gone bankrupt, and the 'IMSAI' trademark was acquired by Thomas "Todd" Fischer and Nancy Freitas (former early employees of IMS Associates), who continued manufacturing the computers under the IMSAI name as a division of Fischer-Freitas Co. Support for early IMSAI systems continues to this day.

Uses 
The IMSAI 8080 was used for
 Small business data processing applications
 Data communications and data entry systems
 Scientific applications
 Computer sciences education and development
 Banking and insurance applications
 Military and general government applications
 Personal computer systems

IMSAI in popular culture
An IMSAI 8080 and an acoustic coupler type modem were among the hacking tools used by the main character in the 1983 movie WarGames. However, even by 1983 the acoustic coupler was out of date. It was selected over a more modern model so that the audience would immediately recognize it as the device that connected to the telephone.

Related pages
 Altair 8800

More reading 
 THE HISTORY OF IMSAI: The Path to Excellence, produced 1978
 Jonathan Littman, Once Upon a Time in Computerland: The amazing Billion Dollar tale of Bill Millard's Computerland empire, 1987,

References

Other websites
 Distributor of IMSAI parts, docs and the Series Two model
 Short description of the IMSAI 8080 with photos
 The History of the IMSAI 8080
 Obsolete Technology website - IMSAI 8080 
 The Computer Science Club - IMSAI 8080 
 old-computers.com - IMSAI 8080 
 Collection of old digital and analog computers at oldcomputermuseum.com
 Marcus Bennett's IMSAI Documentation resource 

Computers