The National Museum of Computing celebrates the 75th anniversary of Colossus with new revelations

The National Museum of Computi...
The Colossus Mark II was the second of 10 Colossus computers
The Colossus Mark II was the second of 10 Colossus computers
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The Colossus Mark II was the second of 10 Colossus computers
The Colossus Mark II was the second of 10 Colossus computers

The National Museum of Computing at Bletchley Park, Buckinghamshire, UK is marking the 75th anniversary of the Colossus Mark II computer today with new revelations about its role in winning the Second World War. At a gathering of those who operated what was one of the world's first electronic computers, the museum will disclose how intelligence gathered by the code-breaking machine helped the Allied war effort in ways that even the computer veterans were unaware of.

On June 1, 1944, the Colossus Mark II computer went online. It was the second of the 10 Colossus machines that were built by the British to break the German Lorenz ciphers that were used to encrypt top secret messages from the Nazi high command and Adolf Hitler himself. Less well-known than the more famous Enigma code, Lorenz was much more complicated and much harder to break.

The previous electromechanical decrypting machines weren't up to the task, so the Bletchley Park team under Thomas "Tommy" Flowers, a General Post Office (GPO) telephone electrical engineer who'd been developing a digital electronic telephone switching system using radio valves, created the first true electronic computer, Colossus.

Colossus Mark I booted up on February 5, 1944 and was so successful that more of the computers were ordered. The Mark II went into service on June 1. According to the museum, this may have been so that the computer could handle the German code traffic during the build up to the still-secret D-Day invasions by the Allied forces, which were to land on the beaches of Normandy on June 6.

Because of the strict secrecy that surrounded the decoding project, the very existence of Colossus was unknown to almost everyone outside the intelligence services until the 1980s, and even during the war the Wrens (Women's Royal Naval Service) had no idea of the significance of their work tending the computer. As part of today's ceremony, the surviving women of the team and others will learn whole story.

The museum says that the event speakers will discuss the pressures of the D-Day code-breaking effort, as well as the results of their National Archives research on the intelligence results from Colossus for the Allied landings – especially how it confirmed that the Germans had fallen for the Allied disinformation campaign to fool the Axis as to when, where, and how the invasion would come.

Source: The National Museum of Computing

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I cannot overstate my admiration for Tommy Flowers. Not only did he conceive the idea of the digital process to enable bulk decryption, he also built it using largely his own money. He actually spent around £1000 of his own, which at that time would bought the average house in London.
Alan Turing has rightfully received so much attention for his codebreaking work, but his work would have meant nothing without the ability of Tommy Flowers invention to decrypt the intercepts quickly.
Thank goodness he is now receiving some belated recognition of his outstanding work!