Thomas “Tommy” Flowers is perhaps one of the most important and least known people in modern computing history. Born on this date, Dec 22, in 1905, Flowers developed the first electronic programmable computer, known as Colossus.
Colossus was designed specifically for decoding intercepted communication between the top leadership of the Nazi party including Hitler, Admiral Durnetz and Field Marshall Rommel as well as their generals on the battlefront. The Germans entrusted their most secret messages to a machine known as the Lorenz SZ40 cipher system, which they used from 1941 until the end of World War II in 1945. It was Flowers who developed the computer that was able to secretly decipher the messages of the Nazi high command.
Flowers was a British engineer that was hand picked by Max Newman to be part of a special team at Bletchley Park to improve the semi-automated decoding process of the Lorenzo Cipher. When Flowers arrived at Bletchley Park in 1941 most of the decoding was being done by hand and on a rudimentary machine known as ‘Robinson’. The process was painstakingly slow and error prone.
Flowers proposed building a different type of decoding machine that was based on 1,800 thermion valves (vacuum tubes) that would serve as of series high speed reliable electronic logic gates. The idea was so radically different that his superiors refused to provide a budget for the project thus forcing him to fund a great deal of the project with his own money to the tune of over £1000. £1000 was a considerable amount of money in 1941 and Tommy Flowers was not a wealthy man.
During the time that Flowers and his team were building the Colossus at his Dollis Hill laboratory, 1941 to late 1943, the German’s improved their level of encryption several times on the Lorenz thus significantly reducing the number of intercepted messages that could be decrypted by the codebreakers and the Robinson.
Flowers first generation Colossus was delivered and installed on February 5, 1944, it was immediately put to work. The Colossus quickly doubled the codebreakers output and silenced the critics at Bletchley Park. The new computer eliminated the synchronised tapes of the Robinson, boasted superior speeds by a factor over 5 times and was also much more reliable, due to Flowers’ redesigned counters and the use of valves in place of relays throughout.
The Bletchley Park authorities immediately ordered 4 more units from Flowers and insisted that the next one be delivered by June 1, 1944. After many sleepless nights and considerable stress, Flowers and his team had Colossus II operational on time. The new machine was faster and more reliable than it’s predecessor.
On June 5, 1944 the codebreaking team was able to successfully decode a message from Adolf Hitler to Field Marshall Rommel and other his high command leaders on the strategy for defending the Western Front (the Atlantic Wall) against an Allied invasion. Hitler believed that the Allied forces would invade Normandy as a decoy to draw the German defenses away from what he felt was their true invasion spot of France’s Pas de Calais region. Hitler had the Pas de Calais region well fortified and did not want his military resources to be redeployed to Normandy for what he believed was a red herring. He ordered all of his commanders to stand firm for 5 days if the Allied forces launched an assault of Normandy as he didn’t want to weaken his strong hold positions.
Bletchley Park immediately passed the intercept onto the Americans and General Eisenhower issued the order to launch a full scale invasion, known as D-Day, at Normandy for the very next day, June 6, 1944. He knew from Hitler’s broken communication that he would have the element of surprise and ample time to overwhelm the defending German forces on Omaha Beach.
The hard fought victory for the Allies at D-Day was the turning point in the war in that it allowed the Allied troops the ability to advance by land into Germany. World War II was over with a year from D-Day.
The German high command continued to use the Lorenz Ciper Machines after D-Day but they changed the frequency of the encryption key decoding on a more regular basis. Several Colossus (aka Colossi) computers were dedicated to just breaking the ever-changing key decoding while several others were used to decode the actual communication. By the time the war ended in 1945 there were 10 Colossus computers in active service.
The entire Colossus program was classified, 8 of the Colossus computers were disassembled immediately at the conclusion of the war and the remaining 2 were disassembled in 1958-60.
For Tommy and Colossus, the work that was done at Bletchley Park was to remain a secret for a very long time. Tommy Flowers kept his word and remained silent about his contribution to the war effort. No doubt others benefited from his work, but Tommy did not. He never revealed these secrets, only doing so when the restriction was lifted.
The American Government was given the details of Colossus by the British Government as part payment for all the food and armaments America had supplied throughout the war. It’s rumored that many of the technical specifications of Colossus were shared with the team that was developing ENIAC at the University of Pennsylvania.
The secret Colossus program was initially revealed by the USA’s Freedom of Information Bill in 1970 and the release of the information Britain had given the USA.
Recognition came after the release of the Colossus information but much too late to give Tommy any real benefit. He received an honorary doctorate from Newcastle University in 1977, and another from De Montfort University in Leicester. More was planned. It became known that he was being considered for a knighthood, possibly in the New Years Honors List. Sadly, Tommy Flowers died from heart failure at home in London on October 28, 1998. He was 92.
Flowers significant contributions in computer science have been credited by Prime Minister Winston Churchill and General Dwight Eisenhower with shortening World War II by at least 2 years and saving at least hundreds of thousands of lives.