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.