http://georgetoft.com/georgeslaw.shtml
From my college days . . .
"Hey, Grampa, tell us the story about 80 column punch cards, and why a
good rubber band was your best friend. You mean you couldn't just talk
to the computer?"
"Well, Sonny, columns 1-5 were for your numeric labels. A 'C' in column
6 meant it was a continuation from the previous line, and your code went
in columns 7-72. Columns 73-80 were your card sequence number and it was
optional. Nobody liked to put numbers there because if we moved a block
of code, we would have to resequence the cards. Screw that - just make
sure you had a good rubber band, and another one as a backup in case the
first one broke. Gives you a whole new meaning of data backup, huh."
"Grampa, what was the deal with column 1 on the printer?"
"Oh, yeah. Put a 1 in column 1 and the printer won't advance. Print
about 10 lines with this:
1====================================================
and all of the print wheels on the line printer would line up and the
strikers would synchronize and go WHOMP WHOMP WHOMP and shake the whole
computer center. Heh, heh, heh. The computer operators would jump out of
their skin - they definitely knew when I ran a job."
"Grampa, what's a line printer?"