IMSAI 8080

|colspan=2 style="color: white; background: gray;"|IMSAI 8080|
| --- | --- |
|colspan=2||
|**Manufacturer**|IMS Associates, Inc., later IMSAI Manufacturing Corporation|
|**Type**|Hobbyist computer|
|**Casing**|Aluminum|
|**Production**|December 1975|
|**Discontinued**|1978|
|**CPU**|Intel 8080/8085A @ 2 MHz/3 MHz|
|**RAM**|256/4K bytes on a 4K board (static), 16K, 32K, 64K Dynamic RAM|
|**Expansion**|22-slot motherboard S-100 bus|
|**Software**|First commercial supplier of Digital Research's CP/M (Control Program/Monitor), later followed by IMDOS, BASIC, FORTRAN|
|**Storage**|Optional cassette or 5 1/4" and 8" floppy drives, hard drives (CDC Hawk- 5 MB fixed, 5 MB removable|

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,

## 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