Colossus

from Wikipedia, the free encyclopedia
Colossus Mark II

Colossus (plural: Colossi ) was an early tube computer built in England during World War II specifically to decipher classified messages from the German military. With his help, the deciphering of the German Lorenz key machine in Bletchley Park became possible from 1943 onwards .

history

A radio telex sent encrypted from Berlin to Army Group Courland on February 14, 1945 using the Lorenz key machine , which was deciphered in BP as a Tunny message .

The encryption method - generation of pseudo-random numbers and exclusive decoding - was recognized by a serious mistake by a Wehrmacht soldier during one of the first test attempts: a message about 4000 characters long with slightly different text, but with the same pseudo number sequence, was transmitted twice, which was strictly forbidden.

The Germans used a key that changed every day and produced different sequences of numbers. Each message therefore had to be deciphered separately. Manual decryption of a message took several days to weeks. The information contained was then usually worthless. The design of the machine, based on ideas for a universal machine from Alan Turing , came from Max Newman , who recognized that deciphering can be significantly accelerated with the aid of a machine. The machine was built by Tommy Flowers at the British Post Office's research center in Dollis Hill .

Structure and performance

Colossus initially (1943) consisted of 1,500 tubes , later of 2,500. With a power consumption of 4,500 W , the machine could process an astonishing 5,000 characters (5 bits each) per second. The memory consisted of 5 characters of 5 bits each in shift registers . The characters were read photoelectrically from a punched tape, the row of holes in the middle of the strip generated the clock, at 5000 characters / sec that is 200 µs. About 100 Boolean operations could be performed on each of the five rows of holes and then on a character matrix in parallel within one cycle . The hits were then counted.

A total of ten devices were built between 1943 and 1946. Colossus allowed a message to be deciphered within a few hours. Colossus is considered to be the first large electronic computer (tube computer). The special computer originated before the huge American tube computer ENIAC , but after the small electronic Atanasoff-Berry computer . Colossus was not used against the Enigma.

First large electronic computer

Colossus was not a programmable computer, but designed as special computers for the breakdown of "Tunny" messages . It was programmed via cable connections and switches. Its existence was kept secret until the 1970s. The first programmable digital computers from the Universities of Manchester and Cambridge can be regarded as successors.

Replica by Tony Sale

Tony Sale (right) in 2006 during a decipherment with the completed machine.
General view of the Colossus replica (2015)

It wasn't until 1970 that Colossus became publicly known. From 1990, Tony Sale , engineer and former employee of the MI5 intelligence service , built the Colossus for the Computer Museum in Bletchley Park . On June 6, 1996, it had its first successful run. For the official inauguration of the device on November 16, 2007, German radio amateurs sent a text encrypted with an original Lorenz machine . Colossus " cracked " the message in three hours and 35 minutes, it contained an invitation to an exhibition with historical computers in the Heinz Nixdorf MuseumsForum , Paderborn . Deciphering was delayed by around 45 minutes because one of the computer's 2,400 tubes had burst. In the competition held in parallel to the broadcast, an amateur radio operator managed to pick up the signal with his club's antenna, process it acoustically and finally decipher it in 46 seconds with a laptop running FreeBSD .

The replica of the Colossus can be seen at the National Museum of Computing in Bletchley Park.

Colossus - the movie

In 1970 the science fiction thriller “ Colossus: The Forbin Project ” was created based on a novel by Dennis Feltham Jones . Although it does not explicitly refer to its older namesake, parallels can still be seen: A gigantic supercomputer, embedded in the interior of a mountain, is supposed to help secure world peace. Professor Forbin (played by Eric Braeden ), the ingenious developer of the computer giant, which is even supposed to survive a nuclear war, does not count on the dangerous potential of his creation.

Comparison with other early computers

Computer model country Installation Floating point
arithmetic		 Binary Electronically Programmable Mighty Turing
Zuse Z3 Germany May 1941 Yes Yes No Yes, using punched tape Yes, without any practical use
Atanasoff-Berry computer United States Summer 1941 No Yes Yes No No
Colossus UK 1943 No Yes Yes Partly, by rewiring No
Mark I. United States 1944 No No No Yes, using punched tape Yes
Zuse Z4 Germany March 1945 Yes Yes No Yes, using punched tape Yes, without any practical use
around 1950 Yes Yes No Yes, using punched tape Yes
ENIAC United States 1946 No No Yes Partly, by rewiring Yes
1948 No No Yes Yes, using the resistor matrix Yes

literature

  • Bengt Beckmann, KO Widmann: Arne Beurling and Hitler's secret writer. Swedish deciphering successes in WWII. Springer, Berlin et al. 2006, ISBN 3-540-23720-8 .
  • B. Jack Copeland : Colossus. The Secrets of Bletchley Park's Code Breaking Computers. Oxford University Press. Oxford et al. 2006, ISBN 0-19-284055-X .
  • Paul Gannon: Colossus. Bletchley Park's Greatest Secret. Atlantic Books, London 2006, ISBN 1-84354-330-3 .

Web links

Commons : Colossus computer  - collection of images, videos and audio files

swell

  1. ↑ a b The code cracker - British reconstruct computers from the Second World War , Süddeutsche Zeitung , No. 265, p. 24, 17./18. November 2007