The Jargon File (version 4.4.7, 29 Dec 2003):

walking drives
 n.

    An occasional failure mode of magnetic-disk drives back in the days when
    they were huge, clunky washing machines. 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.


The Free On-line Dictionary of Computing (30 December 2018):

walking drives

    An occasional failure mode of magnetic-disk drives
   back in the days when they were huge, clunky washing
   machines.  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.

   [Jargon File]

   (2009-05-14)