: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 {microtape}s 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.)
-- The AI Hackers Dictionary
