After his success with COLOSSUS, Max Newman, Turing’s old lecturer, moved to a chair at Manchester University in late 1945 where he worked on the design of an electronic digital computer. Through Hartree (see next section) and Flowers, he was introduced to the ideas of the EDVAC report.

In the summer of 1946 Freddie Williams (of the Telecommunications Research Establishment) started work on an electronic storage device based upon the use of the Cathode Ray Tube (an idea from the Radiation Laboratory at MIT in the USA) - the same device that allows you to see pictures on your television screen. Later that year he moved to Manchester and largely took over the computer work, working closely with Tom Kilburn, also from T.R.E.

The Manchester Prototype (or 'Baby'), which was the first Manchester machine, had a store of only 32 words and no form of mechanised input or output. Consequently its usefulness was very limited as compared to the ENIAC.

Nevertheless, when it first ran a program on 21st June 1948 it became the first working stored program electronic computer to hold its program in a read-write store. Its distinction from the ENIAC, which ran the very first stored program, is that the Manchester Baby, unlike ENIAC, had a read-write store, thus allowing the programs to modify themselves as they ran and making them more versatile.


Following the construction of the prototype, Williams and Kilburn went on to construct two more, improved specification computers based on the design of the Manchester Baby. One of these computers began operation just before EDSAC (the Manchester Mark I) but did not become fully operational with input and output until somewhat after EDSAC, in the summer of 1949.

This machine attracted Government attention and Ferranti Ltd was given Government funding to support the production of a computer. The Ferranti Mark I was delivered in February 1951 and is believed to have been the first commercially available stored program electronic digital computer.

The early Manchester series of machines, starting with the Prototype and the Manchester Mark I (which itself went through several versions) had an advantage over other early machines in using the fast Williams store.

Tom Kilburn

Frederic C. Williams