= P =
patch space n.
An unused block of bits left in a binary
so that it can later be modified by insertion of machine-language
instructions there (typically, the patch space is modified to
contain new code, and the superseded code is patched to contain a
jump or call to the patch space). The near-universal use of
compilers and interpreters has made this term rare; it is now
primarily historical outside IBM shops. See patch (sense 4),
zap (sense 4), hook.
--The Jargon File version 4.3.1, ed. ESR, autonoded by rescdsk.