flap
vt. 1. 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 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. See also macrotape. 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.)