= B =
BLT /B-L-T/, /bl*t/ or (rarely) /belt/ n.,vt.
for blit. This is the original form of blit and the
ancestor of bitblt. It referred to any large bit-field copy
or move operation (one resource-intensive memory-shuffling
operation done on pre-paged versions of ITS, WAITS, and TOPS-10 was
sardonically referred to as `The Big BLT'). The jargon usage has
outlasted the PDP-10 BLock Transfer instruction from which
BLT derives; nowadays, the assembler mnemonic BLT almost
always means `Branch if Less Than zero'.
--The Jargon File version 4.3.1, ed. ESR, autonoded by rescdsk.