Knuth has said that the story as told above is apocryphal. I quote from here (http://www.informit.com/articles/article.aspx?p=1193856 http://www.informit.com/ar

Knuth has said that the story as told above is apocryphal. I quote from here (http://www.informit.com/articles/article.aspx?p=1193856 http://www.informit.com/articles/article.aspx?p=1193856): > Donald: The story you heard is typical of legends that are based on only a small kernel of truth. Here’s what actually happened: John McCarthy decided in 1971 to have a Memorial Day Programming Race. All of the contestants except me worked at his AI Lab up in the hills above Stanford, using the WAITS time-sharing system; I was down on the main campus, where the only computer available to me was a mainframe for which I had to punch cards and submit them for processing in batch mode. I used Wirth’s ALGOL W system (the predecessor of Pascal). My program didn’t work the first time, but fortunately I could use Ed Satterthwaite’s excellent offline debugging system for ALGOL W, so I needed only two runs. Meanwhile, the folks using WAITS couldn’t get enough machine cycles because their machine was so overloaded. (I think that the second-place finisher, using that "modern" approach, came in about an hour after I had submitted the winning entry with old-fangled methods.) It wasn’t a fair contest. > As to your real question, the idea of immediate compilation and "unit tests" appeals to me only rarely, when I’m feeling my way in a totally unknown environment and need feedback about what works and what doesn’t. Otherwise, lots of time is wasted on activities that I simply never need to perform or even think about. Nothing needs to be "mocked up."