flap

vt. 1. [obs.] To unload a DECtape (so it goes flap, flap, flap...). Old-time
hackers at MIT tell of the days when the disk was device 0 and DEC
microtapes were 1, 2,... and attempting to flap device 0 would instead start
a motor banging inside a cabinet near the disk. 2. By extension, to unload
any magnetic tape. Modern cartridge tapes no longer actually flap, but the
usage has remained. (The term could well be re-applied to DEC's TK50
cartridge tape drive, a spectacularly misengineered contraption which makes
a loud flapping sound, almost like an old reel-type lawnmower, in one of its
many tape-eating failure modes.

