patch space

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code, and the superseded code is patched to contain a jump or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 widening use of HLLs has made

this term rare; it is now primarily historical outside IBM

shops. See patch, zap, hook.

[Jargon File]