Synonym 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
.