Advanced Technology Airborne Computer
The Advanced Technology Airborne Computer was a product of Itek, used on US naval aircraft, and the NASA Galileo.
The ATAC was built using AMD 2901 4-bit processors and had a basic cycle time of 250 ns. It could be programmed in HAL/S, and could be microprogrammed to add new instructions. The Galileo project added four instructions.
Use by Galileo project
The Galileo Attitude and Articulation Control System was controlled by two Itek Advanced Technology Airborne Computers, built using radiation-hardened 2901s. The project wrote their own GRACOS.The Galileo project had radiation-hardened 2901 processors made for the spacecraft.