The truth about Colossus - Decoding computer over 2m high used in World War II

The massive Colossus computer takes up as much space as a room, reducing code-breaking time from weeks to hours .

British intelligence agency GCHQ released never-before-seen images of Colossus , the secret British decryption computer that helped the Allies win World War II, BBC reported on January 18. GCHQ released these images to celebrate the 80th anniversary of the invention of the Colossus, the device considered by many to be the first digital computer . The series of photos brings new information about the origin and operation of the computer.

The computer decodes the Colossus code. (Photo: Reuters/GCHQ)

Colossus's existence was kept secret until the early 2000s. "Technological innovation is always at the heart of our work at GCHQ, and Colossus is a perfect example of how our employees help us at the forefront of new technology - even when we can't talk about it ," said Anne Keast-Butler, director of GCHQ.

Bletchley Park Castle , Britain's code-breaking center, successfully cracked the Enigma code used by the Nazis. But in 1943, the Germans used a new and more complex cryptographic system called Lorenz. The messages took up to eight weeks to decode by hand while the codes changed every night, requiring Britain to develop a new electronic computer system to break the Lorenz cipher quickly enough.

British engineer Tommy Flowers spent 11 months designing and building the Colossus at Dollis Hill, northwest London. After testing and inspection, the Colossus Mark I version was transported to Bletchley Park in December 1943 - January 1944. Here, the machine was installed by Harry Fensom and Don Horwood, then went into operation in early 1944.

The first Colossus version was equipped with about 1,600 valves. It was so effective that by the end of World War II, about 10 had been built, including a faster Mark II version with about 2,500 valves. It occupies a space equivalent to a living room with a height of more than 2 meters, a length of about 5 meters and a width of 3.4 meters. The machine weighs about 5 tons and uses 8 kW of power, equipped with about 100 logic gates and 10,000 resistors connected by 7 km of wire.

Colossus helps speed up solving the complex Lorenz cipher from weeks to just a few hours. Historians say computers helped shorten the war. Colossus requires a team of highly skilled operators and technicians for operation and maintenance. By the end of the war, 63 million characters in high-level German messages had been decoded by 550 people working on computers. After the war, 8 out of 10 computers were destroyed.

"From a technical perspective, the Colossus was an important forerunner of the modern digital electronic computer. Of those who used the Colossus at Bletchley Park, many went on to become pioneers and leaders importance of the computer industry in the UK in the following decades ," said Andrew Herbert, an expert at the British National Computer Museum.