【Fujitsu】 FACOM 463K Disk File Unit

Completed in June 1969, the FACOM 463K was a disk file unit from Fujitsu which employed a removable media housing a single 14-inch disk inside a cartridge, and a fixed head system.

This unit was developed as a high-speed, high-capacity auxiliary memory unit and external memory unit for the FACOM 230-10D small computer (an improved model of the FACOM 230-10) by using the results and knowledge obtained with the FACOM 631A/B magnetic disk unit. A maximum of 3 units could be connected to the DFC (Disk File Channel) of the FACOM 230-10D.

The heads of this unit were the air floating type, and 36 heads were fastened around the entire cartridge. Each head was equipped for 2 tracks, and data on 72 tracks could be accessed without moving a head. Therefore the system had high-speed access times like a magnetic drum. Average access time with 60Hz drive was 16.7ms. The cartridge had a disk with diameter of 37cm and a weight of approximately 1.5kg, and the memory capacity of one side was 131,072 bytes. Both sides of the disk could be used by remounting the disk.

Specifications of FACOM 463K Disk File Unit
Completion date June 1968
Memory capacity 131,072bytes (8bits/byte)
Capacity per track 2,048bytes
Capacity per record 256bytes
Number of records/track 8
Number of tracks/side 72tracks
Average access time 16.7ms(60Hz)/20ms(50Hz)
Disk rotation speed 1,800rpm (60Hz)/1,500rpm(50Hz)
Data transfer speed 73.7 Kbyte/s(60Hz) /
61.3 Kbyte/s(50Hz)
Connected system FACOM 230-10D

FACOM 463K Disk File UnitDisk of FACOM 463K Disk File Unit