1. vt. To make highly efficient, either in time or
space, often at the expense of clarity. "I managed to bum three
more instructions out of that code." "I spent half the night
bumming the interrupt code." In 1996, this term and the practice it
describes are semi-obsolete. In elder days, John McCarthy
(inventor of LISP) used to compare some efficiency-obsessed
hackers among his students to "ski bums"; thus, optimization
became "program bumming", and eventually just "bumming". 2. To
squeeze out excess; to remove something in order to improve
whatever it was removed from (without changing function; this
distinguishes the process from a featurectomy). 3. n. A small
change to an algorithm, program, or hardware device to make it more
efficient. "This hardware bum makes the jump instruction
faster." Usage: now uncommon, largely superseded by v. tune
(and n. tweak, hack), though none of these exactly
capture sense 2. All these uses are rare in Commonwealth hackish,
because in the parent dialects of English the noun `bum' is a rude synonym
for `buttocks' and the verb `bum' for buggery.