The Altair 8800b was the second computer in the 8800 series from MITS. It was introduced in June 1976. The original Altair 8800 was introduced in January 1975. Costing less than $400 in kit form, it is widely recognized as the computer that ignited the home microcomputer revolution.

The 8800b computer is a general purpose byte-orientated machine (8-bit word). It used a common 100-pin bus structure that allowed for expansion of either standard or custom plug-in modules. It supported up to 64K of directly addressable memory and could address 256 separate input and output devices. The 8800b computer had 78 basic machine language instructions and is made up of a power supply board, an interface board, a CPU board, and a display/control board.

There were several changes and additions made to the 8800b. Five new front panel switch positions were added to expand the front panel capability: SLOW, DISPLAY ACCUMULATOR, LOAD ACCUMULATOR, INPUT ACCUMULATOR, and OUTPUT ACCUMULATOR. The CPU board featured the 8080A microprocessor, and the Intel 8224 clock, running at 2MHz. The four-slot expander cards in the Altair 8800 were replaced by a single piece 18-slot motherboard which contained 100 solder lands which comprise the 100 pin bus.

The 8800b ran Altair BASIC, which was developed by Microsoft, and was their first product. It was distributed by MITS under a contract. The 8800b was compatible with all existing 8800 software and hardware.

This example in our collection has been fully restored and is in working condition.

Manufacturer: MITS
Date: 1st January 1975

This exhibit has a reference ID of CH40645. Please quote this reference ID in any communication with the Centre for Computing History.