Large Computer Rescue

long ago as a student programmer, i had a summer job to port 1401 MPIO program to 360-30. basically MPIO acted as front-end they could run 360-30 in 1401 hardware emulation mode and run original MPIO ... so maybe it was just a make-work job for student programmer.

i got to design and implement my own supervisor, task manager, device handlers, storage manager. it was eventaully about 2000 source buttembler cards ... and my default mechanism was to buttemble it under os-360 and then reboot the machine with stand-alone loader.

to fix a bug in source and re-buttemble ... was approx. an hour elapsed time ... rebooting os360, and then re-buttembling my source program (which took half hour elapsed time). so i got relatively good at patching the "binary" card output of the buttembler. I hadn't discovered "REP" cards ... so I would find the appropriate card ... and "multi-punch" a patch using a 026 keypunch (i.e. duplicate the card up to the patch, multi-punch the patch on the new card and then finish duplicating the rest of the card). after a while i got so i could read the key-punch holes as easily as i could read and interpret hex (I could fan the card deck looking for the TXT card with the relative program address of the location needing patching ... i.e. translating the punch holes in the card address field into hex).

one representation that still sticks solidly in my mind is 0-2-9 punch holes for hex '02'. convention was that buttembler and compiler binary executable output cards had 0-2-9 in column one, followed by executable control card "type" (i.e. ESD, TXT, RLD, END, etc).

misc. past posts mentioning 0-2-9 and-or various 0-2-9 card formats