In 1948, the first stored computer program was run, on Manchester Mark I.
The program was to determine the highest factor of a number. The number chosen was quite small, but within days they had built up to trying the program on 218, and the correct answer was found in 52 minutes, involving about 2.1 million instructions with about 3½ million store accesses.
Learn more at http://www.computer50.org/mark1/new.baby.html
