We were asked to describe the simplest, most amazing code we had ever written or witnessed.
My answer should probably be some esoteric APL code that I personally wrote, like inverting a matrix with a single character program, but many of my readers wouldn’t understand it. In any case, modesty prevents me from choosing my own code.
So, instead, let me tell the story that took place long ago when we were installing an IBM 709 in Bermuda, as part of the NASA space-tracking network. The 709 was a “naked” installation, with little surrounding peripheral equipment, and nothing like it in Bermuda to help us.
In particular, we didn’t have an off-line printer or a punch-card duplicator, so we needed to use the 709 itself to do these jobs—but we had no utilities because we were probably the only naked 709 in the world.
My colleague, Marilyn, who was by far the best programmer I ever knew, went to our keypunch (the only unattached peripheral we had), inserted a blank card, and proceeded to punch (in row binary) a card-to-card duplicator program for the 709. She did it as I watched, in a single pass through the keypunch.
You’d have to understand row-binary format to appreciate what a feat this was—multiple punched columns of alternate instructions in binary. To top it off, she actually punched in (in the same pass) the self-loading program AND the parity check row for her entire card.
She then loaded this card into the 709’s card reader, picked it up and reentered it as input to itself, and so punched a duplicate. She took the duplicate to the keypunch and added one punch to one of the rows. She now had a 709-to-printer program—two incredible error-free programs for the price of one.
I’ve never seen anything like it before or since. Until that time, I thought I was a pretty good programmer. After Marilyn’s feat, I realized that the best I could ever hope to be was Number Two.
How about you? Any amazing code stories to share?