Manchester Baby
The first electronic stored-program computer, which ran its first program on 21 June 1948.
The Manchester Baby, also called the Small-Scale Experimental Machine, was built by Frederic Williams, Tom Kilburn and Geoff Tootill. It ran its first program on 21 June 1948.
It was a testbed for the Williams tube, the first truly random-access memory. The Baby had a 32-bit word and 32 words of memory. Its first program had 17 instructions and ran for about 52 minutes to find the highest proper divisor of 262,144.
Why it matters
It was the first working machine to contain all the elements essential to a modern electronic digital computer. Its successor became the prototype for the Ferranti Mark 1, the first commercially available general-purpose computer.
Key facts
- Ran its first program on 21 June 1948.
- Built by Williams, Kilburn and Tootill.
- 32-bit word, 32 words of memory.
- Tested the Williams tube memory.
- First program had 17 instructions and ran about 52 minutes.
Sources
- Wikipedia, "Manchester Baby", en.wikipedia.org/wiki/Manchester_Baby, accessed October 14, 2026.
- Wikipedia, "Frederic Calland Williams", en.wikipedia.org/wiki/Frederic_Calland_Williams, background reading, accessed October 14, 2026.