Changes

Colossus was designed to deal with the complex intelligence known as Fish, with messages sometimes 10,000 characters in length sent between Hitler's High Command and commanders in the field, and containing vital information on troop dispositions, ration strengths, and even details of leave arrangements for generals. The Morse-transmitted Enigma code, on the other hand, although very complex, used messages of a purely tactical nature, which were never more than 250 characters long. This work had no association with Colossus.

Colossus was designed to deal with the complex intelligence known as Fish, with messages sometimes 10,000 characters in length sent between Hitler's High Command and commanders in the field, and containing vital information on troop dispositions, ration strengths, and even details of leave arrangements for generals. The Morse-transmitted Enigma code, on the other hand, although very complex, used messages of a purely tactical nature, which were never more than 250 characters long. This work had no association with Colossus.

Colossus was engaged on the statistical analysis of the enemy teleprinter intercepts. A separate machine to use this data to decipher each message was needed, and Flowers arranged for me, a former member of the DH staff, then in the Army in North Africa engaged on another DH-backed project, to be posted home to join his team. Busy though he was, Flowers made a daily visit to his small band working in a small laboratory to observe progress.

Colossus was engaged on the statistical analysis of the enemy teleprinter intercepts. A separate machine to use this data to decipher each message was needed, and Flowers arranged for a former member of the DH staff, then in the Army in North Africa engaged on another DH-backed project, to be posted home to join his team. Busy though he was, Flowers made a daily visit to his small band working in a small laboratory to observe progress.

The new machines, codenamed "Tunny", were to be fed with an enciphered message tape, and after being set up according to the Colossus data, were to produce a printed output on a teleprinter in clear German. To facilitate the testing of Tunny, one of the design engineers devised a certain set of code wheel patterns, and on his next visit Flowers was invited to type in the message "Now is the time for all good men to come to the aid of the party". He and his team worked a 12- or 14-hour day throughout the war without complaint.

The new machines, code-named "Tunny", were to be fed with an enciphered message tape, and after being set up according to the Colossus data, were to produce a printed output on a teleprinter in clear German. To facilitate the testing of Tunny, one of the design engineers devised a certain set of code wheel patterns, and on his next visit Flowers was invited to type in the message "Now is the time for all good men to come to the aid of the party". He and his team worked a 12- or 14-hour day throughout the war without complaint.

==Later Career==

==Later Career==