An IBM utility program used to quickly patch operating system or application program executable code or disk VTOCs in preference to editing the source code and recompiling. SuperZap could write data given as a string of hex digits to a given disk location in a matter of seconds.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. 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. The program name owed less to its use of the Zero and Add Packed (ZAP) instruction and more to SF films in which aliens were zapped with lasers. [2004-02-05 e-mail from Chris Gage and 2015-01-03 email from Ray Saunders, both IBM employees and SuperZap users].
Last updated: 2021-03-21