DISK  DRIVES   and   CONTROLLERS


In this  disk  folder are descriptions of all the disk drives and their controllers that I have in my collection :

RL and RK disk drives


Picture view of disk drive technology advances
One RA81 disk drive, with on top of the RA81 the Fujitsu M2322K disk drive. These Fujitsu disk drives were quite common on the more modern UNIBUS PDP-11's, like the PDP-11/44. The M2322K needs 3 power supply voltages (+24V, +5V and -12V) and the energy requirement is 144 W. The Fujitsu in the picture (with the cover removed to expose the platters and the heads) is dated October 1986. The M2322K disk drive weighs a bit more than 11 kilos and has a capacity of 168 Mb.
RA81 and Fujitsu M2322K disk drives
And for comparison, here you see that same Fujitsu M2322K disk drive. On the top platter lies a modern IDE disk drive used in laptops, year 2005. This IDE disk drive has a capacity of 40 Gb ...! This IDE drive weighs approximately 82 grams, compare that, its capacity and power requirements with an RA81.   An RA81 weighs a bit more than 67 kilos, has a capacity of 456 Mb and energy requirement of 644 W! But then, unlike the Fujitsu and the IDE drive, the RA81 has its power supply incorporated in the drive ...
IDE laptop disk drive and Fujitsu M2322K