Reverse engineering circuitry in a Spacelab computer from 1980

A reverse-engineering analysis of an ALU board from the Mitra 125 MS minicomputer used in Spacelab. The 16-bit computer lacked a microprocessor, using TTL chips like the 74181 ALU. The article also covers the French computer industry's history, the Plan Calcul, and Spacelab's eventual upgrade to IBM AP-101SL computers.