IMSAI 8080

Information Management Sciences Associates

This system was donated by Patrick "Fitz" Fitzpatrick on 8/13/21.

IMS (Information Management Sciences) Associates was founded in 1973 by William Millard and was based in San Leandro, California. It was renamed IMSAI Manufacturing Corporation 1976. In 1977 IMSAI was facing strong competition from the Z80 microprocessor used in competing systems. Mr. Millard decided that starting a retail store for his and other microcomputer products was the best path forward. He opened Computer Shack, later renamed ComputerLand after Radio Shack objected to the name. ComputerLand sold IMSAI as well as Apple, North Star, and Cromemco products. Millard used IMSAI as a funding source for ComputerLand, and IMSAI quickly was in trouble. IMSAI went bankrupt in 1979, but two IMS employees, Thomas "Todd" Fischer and Nancy Freitas bought the IMSAI trademark. manufacturing continued under the Fischer-Freitas name.

The IMSAI 8080 was introduced in 1975 and was based on the new Intel 8080 microprocessor. It uses the same S-100 bus backplane as the Altair. IMSAI licensed the CP/M operating system from Digital Research, modified it, and sold it as IMSDOS.

Somewhere between 17,000-20,000 IMSAI 8080 systems were produced by IMSAI and another 2,500 were produced by Fischer-Freitas.

Information on our restoration effort is here.

This model of microcomputer was featured in the 1983 movie WarGames. How about a nice game of chess?

The original IMSAI 8080 CPU board from this system has been replaced by a Cromemco Z80 ZPU board Revision E. This is a well designed and very reliable board.

The switches at the top right of the board set the power on jump address and are set to C800h. That is a common address for the boot ROMs on a diskette controller. We received this system without a diskette controller or diskette drives.

This is an early IMSAI 4k RAM board. You can see IMS Associates on the PCB at the bottom left corner, It was designed in 1975, before they changed the company name. It is populated with 32x 256 x 4 bit static RAM chips for a total memory of 4k Bytes or RAM.

Another original IMS Associates board from 1975. This board can provide up to 4x 8-bit parallel I/o ports. This board is only partially populated, so the full 4 ports are not implemented. The LEDs are connected to the first output port and reflect the state of the output signals. The I/O ports are jumpered for I/O addressing, with a base address of 0xE0. The left most port is at address 0xE0, then 0xE1, 0xE2, and 0xE3.

This IMSAI SIO board is a little newer than the RAM boards. It has a date of 1976 and the newer name of the company on it. It provides two serial ports with full modem control signals. The ports have a maximum speed of 56,000 baud. This board also supports 20 mA current loop connections to a Teletype.