FACOM 631A Magnetic Disk Unit

The FACOM 631 was a high-capacity magnetic disk unit from Fujitsu, and the first model, called the FACOM 631A, was completed in 1965. At the time, magnetic disk units from Fujitsu were the only Japanese made disk units, and there were two models, the FACOM 631A and FACOM 631B. They were primarily used with the FACOM 230-20 and FACOM 230-30 mid-size general-purpose computers.