[rescue] Burroughs B1000 series minicomputer disk exerciser

[Nigel Williams]

Anyone familiar with the Control Data range of disk drives? I found a
hit on the instrument plate, for a 844-21 disk drive:

http://www.bitsavers.org/pdf/cdc/cyber/brochures/844-21_Feb74.pdf

the tester instrument plate (higher rez than the craiglist):
http://i.imgur.com/oWb17.jpg
front of the tester: http://i.imgur.com/YSBmp.jpg

But no sign of a 975X or HPD (is this high-performance disk perhaps?)