Daves Old Computers - IMSAI 8080

With the success of the Altair 8800, it wasn't long before others began to join the microcomputer revolution. Although it was already in development by the time the Altair was announced, the folks at IMS Associates realized the value in a standardized architecture and adopted the "Roberts bus" (later to become the S-100 bus) in their design. If the Atlair is the first Personal Computer, then the IMSAI 8080 qualifies as the first Personal Computer clone.

Having the Altair design to study gave IMS a big advantage, and IMSAI 8080 featured a number of improvements: The power supply is stronger, and a large 22 slot single-board backplane provided. The chassis is also of heavier construction, and the front panel design makes it easier to use, and considered by some to be visually superiour to the Altair.

Donated by Richard Parsons.

Click any photo to view a large high-resolution image.

The IMSAI 8080 - Arguably the first personal computer "clone", this machine combines function and form in what may be the most attractive microcomputer ever. The IMSAI gained widespread recognition when it was featured in the 1984 movie Wargames.

Closeup of the IMSAI 8080 front panel. Available in kit form, this particular IMSAI has been consstructed with the front panel switches laid out in octal, which is most compatible with the 8080 microprocessor architecture. Many panels were laid out in hexidecimal such as this one which is all that remains from another machine. Here is a view of the back side of the panel assembly.

Inside the IMSAI 8080 - Note the large one-piece backplane, and heavy duty power supply. The panel is fastened to the front of the machine and plugs into the foremost slot on the backplane. An umbilical cable also connects from the panel directly to the CPU card. Here are views of: Right-side, Left-side, Back, and Bottom.

Installed S-100 cards: IMS: MPU-A, PIO, PROG-8, MITS: 4K-static, TDL: Z16, JTM: 16k, Seals: EPROM, Sigma-100 and a homebrew seral card.

This particular IMSAI used dual tape drives for storage.

The original IMS IMSAI 8080 documentation binder.
IMSAI 8080 User manual (1.8M PDF)
IMSAI 8080 Mainboard manual (1.0M PDF)
IMSAI 8080 Front panel manual (1.4M PDF)
IMSAI 8080 Power supply manual (2.8M PDF)
IMSAI 8080 CPU board (600k PDF)
IMSAI 8080 Parallel I/O board (2.5M PDF)
IMSAI 8080 4K EPROM board (750k PDF)

Early IMS Advertisements (approx 110k JPG each): IMSAI-Jan76, IMSAI-Mar76, 4KRAM-May76, Didn't exist-Aug76, Another side (page2)-Nov76, Experience-Apr77, Power-Jun77, Microcomputers ()-Sep77.