from
The Free On-line Dictionary of Computing (8 July 2008)
SuperZap
<tool, IBM> An {IBM} {utility program} used to quickly {patch}
{operating system} or {application program} executable {code}
in preference to editing the {source code} and recompiling.
The SuperZAP program was a quick hack written by one IBM
Engineer, possibly from IBM UK, in the late 1960s to directly
fix executable files. He needed to fix a bug but it would
have taken hours to rebuild the vast {OS/360} executables.
The {S/360} architecture has an instruction ZAP (Zero and Add
Packed) for {packed decmial} arithmetic, that sets the byte at
a given address to a given value. Superzap used this to write
data given as a string of hex digits to a given location in an
executable file in a matter of seconds.
Soon the IBM development labs were releasing all Programming
Temporary Fixes (PTFs) to OS/360 in this form. OS/360
included a version called IMASPZAP or AMASPZAP which persisted
through {MVS}, {MVS/SP}, {MVS/XA}, {OS/390} and probably still
remains in {z/OS}, the distant descendent of OS/360.
[Private 2004-02-05 e-mail from Chris Gage, IBM employee and
SuperZap user, 1970-].
(2007-03-15)