Quote Originally Posted by PAVB View Post
So it was a check-digit calculation! now I can see it LOL

Man, that was one of the best inventions of the 70's, second only to punching an "*" on column 80 -to signal some exception LMAO
For my money adding a divide by zero fault checking would have been the best invention of the 70's. When I was in high school we had a mini computer with teletype terminals. A disgruntled student would occasionally initiate a divide by zero error, in order to crash the computer, then leave. The people who maintained the computer would spend the next hour trying to recover everything. I suppose it was funny the first few times he did it. Fortunately I was doing all my work on the Atari 800 with a basic cartridge and a cassette tape drive. Not that I am old or anything...