On Fri, 2008-10-24 at 18:09 -0700, Bill Campbell wrote:
The Burroughs Medium Systems mainframes I worked on allowed one to store the program on disk, then compile with modifications in a card deck, using the sequence numbers to replace or insert lines from the cards. There were options to create a new disk file with the patches included, and to resquence the source on disk. Typically there were several card desks in a drawer which could be loaded to recreate the patched disk file by loading them in sequence which was fine until the disk file was resequenced when it was time to punch new cards from the disk file to replace the original deck and patches. Punch cards were far more reliable backup than mag tape and in a pinch one could read the printing on the card to fix a badly damaged card (it was amazing how fast a card reader jam could turn the first card into an accordian fold).
Then came CANDE, TD8xx terminals, and editing on your head-per-track disk. Ah for the good old days, when men were men, and memory upgrades involved fork lifts.
Dave