walking drives

n. An occasional failure mode of magnetic-disk drives back in the days when
they were huge, clunky washing machine s. Those old dinosaur parts carried
terrific angular momentum; the combination of a misaligned spindle or worn
bearings and stick-slip interactions with the floor could cause them to walk
across a room, lurching alternate corners forward a couple of millimeters at
a time. There is a legend about a drive that walked over to the only door to
the computer room and jammed it shut; the staff had to cut a hole in the
wall in order to get at it! Walking could also be induced by certain
patterns of drive access (a fast seek across the whole width of the disk,
followed by a slow seek in the other direction). Some bands of old-time
hackers figured out how to induce disk-accessing patterns that would do this
to particular drive models and held disk-drive races.

