FACOM 231

This was a transistor-based small general-purpose computer, developed by Fuji Tsushinki Manufacturing Corporation (currently Fujitsu) in March 1963. In contrast with previous small computers, which combined a 1-word calculation system with a drum memory system, this machine featured 1-digit calculation (using a variable word length system) and a magnetic core memory (employing 50mil magnetic core memory with a cycle time of 10microseconds). All data was handled in single-digit form, so the arithmetic logic unit and controllers were simplified and price was reduced. The machine achieved a 520/670microseconds arithmetic speed for addition/subtraction (decimal, 10-digit) using a 200KHz basic clock cycle (which was indicated at the time as "200kc"). A variety of configurations could be achieved to suit the application by using the building block structure -- from the paper tape based basic configuration with a memory capacity of 4 Kdigit, to the top-end configuration with devices like magnetic tape and magnetic drum connected, and a maximum memory capacity of 32 Kdigit.