Colossus and the Origins of Programmability Draft for discussion at the 2016 SIGCIS Workshop. Do not quote or cite without permission of the authors. Thomas Haigh (
[email protected]) and Mark Priestley (
[email protected]) This is an initial draft of some material from our ongoing project to explore the history of Tommy Flowers, the ways in which Colossus was used and configured, and its place in the history of information technology. This work is sponsored by Mrs. L.D. Rope’s Second Charitable Trust. The current draft is very preliminary, so please do not quote, cite, or distribute without our permission. If names and references are confusing to you our apologies! Fortunately the basics of Colossus and Bletchley Park are well covered in Wikipedia. Colossus was a codebreaking device built by the British General Post Office at the end of 1943, under the direction of career telecommunications engineer Tommy Flowers. It entered use at Bletchley Park in 1944 to speed the work of codebreakers targeting what was then codenamed “fish,” a family of Lorenz teleprinter codes used for high level German military communication. Colossus was not a one‐off machine, like most early electronic computers, but the prototype for a family of ten “colossi,” in which later models incorporated some significant improvements. The machines were used by the Newmanry, a group under mathematician Max Newman, where ingenious codebreaking users discovered new applications for them which, in turn, shaped the provision of additional controls and capabilities in the later models. Unlike ENIAC, which began in modest secrecy but soon graced the front page of the New York Times, Colossus was highly classified and remained unknown to the public until the 1970s.