Colossus: The Computer No One Knew Existed

BBG just posted some nice photos of Colossus, the code-breaking computer that cracked the German Lorenz ciphers during World War II. It was the first digital programmable electronic computer, developed in complete secrecy by Post Office engineer Tommy Flowers.

Ten of these massive machines were operational by the end of the war, and several remained in service at GCHQ until the late 1950s. What they were used for during the cold war remains a mystery. All of the others were destroyed and the design would have been lost forever if it weren't for the efforts of a team led by Tony Sale, who reconstructed the machine you see here based on the few scraps of information that had not been destroyed after the war.

The fully operational reconstruction is on display at Bletchley Park in Milton Keynes.

Colossus [Boing Boing Gadgets]
The Colossus Rebuild Project
The Design of Colossus [written by Tommy Flowers himself]