Altair 8800b

The Altair 8800 is the Fist model of a microcomputer designed in 1974 by MITS and based on the Intel 8080 CPU.^[2] Interest grew quickly after it was featured on the cover of the January 1975 issue of Popular Electronics^[3] and was sold by mail order through advertisements there, in Radio-Electronics, and in other hobbyist magazines.^[4][5] The Altair is widely recognized as the spark that ignited the microcomputer revolution^[6] as the first commercially successful personal computer.^[7] The computer bus designed for the Altair was to become a de facto standard in the form of the S-100 bus, and the first programming language for the machine was Microsoft's founding product, Altair BASIC.

The Altair 8800b - second and last of the 8800 series - was an improved version of the 8800 model of which it corrected some drawbacks.

Externally, the case had a more professional design, with a smarter back-lit front panel including modified toggle switches and five new functions allowing to read/write/Modify CPU accumulator.

Internally, motherboard could support up to 18 S-100 connectors. It was powered by a stronger power supply unit (8V - 18 amp.). The CPU board was also modified: new 8080A processor and Intel chip sets. However the 8800b remained compatible with all Altair 8800 hardware and software. Unlike the 8800, basic version also had a serial interface for Teletype, video terminal or printer connexion.

System had no bootstrap ROM. User had thus to enter a boot program using panel switches each time the system was switched on. However, every 8800 owners quikly bought or built additional card to expand RAM and ROM memory and connect external peripherals.

The inside of the Altair 8800b