The Original SSEM Machine c. 1949

Today in 1948, the world’s first stored-program electronic digital computer successfully executed its first program. F.C. Williams who designed and built (with Tom Kilburn) the Small Scale Experimental Machine (later nicknamed “Baby”), described the first successful run:

“A program was laboriously inserted and the start switch pressed. Immediately the spots on the display tube entered a mad dance. In early trials it was a dance of death leading to no useful result, and what was even worse, without yielding any clue as to what was wrong. But one day it stopped, and there, shining brightly in the expected place, was the expected answer. It was a moment to remember. This was in June 1948, and nothing was ever the same again.”

Replica of the Small-Scale Experimental Machine (SSEM) at the Museum of Science and Industry in Manchester

To mark the 50th anniversary of the event, a replica of the “Baby” was built by experienced engineers, many of whom made significant contributions in the early days of computing in Manchester. A simulator for the “Baby” was made available, and a competition was organized to find the most interesting new program written for it. The winner was Yasuaki Watanabe from Japan with his noodle-timer program.