This story (and variants) dates back to the IBM2314 disk drive, if not further.
The 2314s were usually cabinet mounted, while the 2311 was a free-standing "washing machine" format. The 2311 had a hydraulic actuator (really).
I'd be more inclined to believe the 2314 variant - it was a disk drive from the mid 60s, 10 platters, 14" no less, a data capacity of 29 megabytes. Oh, and it only did like 3600 RPM and min seek times were in the 50-75ms range (and full-stroke seeks took a lot longer). As a result, you had a lot more mass in the arm assembly, and the full inside-to-outside cycle was down nearer to 100hz where it might conceivably do something useful.
Hewlett-Packard had a 7933 drive some years ago, 404Mbytes, but a large mech and actuator. They were documented in *many* installations (ours included) to dance around a couple of feet or more. With the standalone diagnostics program, you could really make it do tricks.
Jeff
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