flap definition

A symbolic mathematics package for IBM 360.

["FLAP Programmer's Manual", A.H. Morris Jr., TR-2558 (1971) US Naval Weapons Lab].

[Sammet 1969, p. 506].

(01 Mar 1994)

1. <storage, jargon> 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, etc. and attempting to flap device 0 would instead start a motor banging inside a cabinet near the disk.

The term is used, by extension, for unloading 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.

2. <networking> See flapping router.

(01 Mar 1997)

Anything broad and limber that hangs loose, or that is attached by one side or end and is easily moved; as, the flap of a garment. "A cartilaginous flap upon the opening of the larynx." (Sir T. Browne)

2. A hinged leaf, as of a table or shutter.

3. The motion of anything broad and loose, or a stroke or sound made with it; as, the flap of a sail or of a wing.

4. <veterinary> A disease in the lips of horses. Flap tile, a tile with a bent up portion, to turn a corner or catch a drip.

<mechanics> Flap valve, a valve which opens and shuts upon one hinged side; a clack valve.

Origin: OE. Flappe, flap, blow, bly-flap; cf. D. Flap, and E. Flap.

(01 Mar 1998)