On Fri, Oct 24, 2008, Phil Schaffner wrote:
On Fri, 2008-10-24 at 16:16 -0700, Raymond Lillard wrote:
That's why you punch sequence numbers in the last 8 columns. :-)
... and some of the fancier card readers would even sort them for you, but remember to number by some integer >> 1 or you had to redo the whole remainder of the deck to insert a line.
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).
COBOL had the sequence numbers in the first six columns while FORTRAN in the last eight.
I always laughed at the early quiz shows where they had a ``computer'' selecting the questions -- where the computer was really a card sorter that would select the picked question into a specific bin.
Bill