10.5

**Dead medium: The Bletchley Park Colossus**

From: bruces_AT_well.com (Bruce Sterling)

(((This article by Tony Sale came my way through the Fringeware list. Mr. Sales' narrative illustrates just a few of the steep technical, financial and social difficulties involved in resurrecting dead Big Iron. Presumably the reborn Colossus is now up and running. I'd be interested in an eyewitness account of the appearance and function of this living media fossil.)))

The Colossus Rebuild Project Helping to save Bletchley Park

by Tony Sale, FBCS.

The switching on of the rebuilt Colossus on Thursday 6th June 1996 by His Royal Highness the Duke of Kent KG.

Briefing notes.

Colossus was the first large electronic valve computer in the world and it was fully operational in the Spring of 1944, helping to break the German Army High Command messages enciphered using the Lorenz cipher machine. By the end of WW II, ten Colossi were operating in Bletchley Park, the home of Allied code breaking operations. Each one of them used 2,500 electronic valves and they represented a major technological triumph for British invention.

Designed by Dr Tommy Flowers and his team of engineers at the Post Office research labs at Dollis Hill, and manufactured at great speed, they contributed significantly to the war effort by the intelligence that they revealed before and after D Day, 6th June 1944.

The Colossi were special purpose, high speed logic calculators of great reliability. They were kept switched on and running 24 hours a day and operated by girls from the Women's Royal Naval Service, the WRENS.

The very existence of the Colossi was kept a closely guarded secret and unfortunately all but two of them were totally destroyed at the end of 1945. The reasons for this are still not clear. A blanket of silence descended on everything to do with Bletchley Park and this has, until now, prevented Colossus taking its rightful place as one of the greatest achievements of British technology.

It has also allowed the Americans, for far too long, to claim that their ENIAC computer, which first ran in 1946, was the first large electronic valve computer in the world.

The first revelations about Colossus appeared in 1970 when Jack Good, one of the wartime code breakers, gave a brief description in a journal article. This was followed in 1972 by further revelations by Donald Michie, another of the code breakers, and then by the researches of Prof Brian Randell. But even then Colossus was classified as secret and only a few photographs and general details were allowed out.

In 1993 Tony Sale had just finished working at the Science Museum in London restoring some early computers back to working order. Having studied all the available meagre details about Colossus, he decided that given his early career in valve electronics, his involvement with Ml5 and subsequent long career in computing, it would be possible to rebuild a working Colossus.

An approach to GCHQ resulted in all the hardware details about Colossus being declassified, and a further set of wartime photographs emerged from GCHQ archives. Some of the original engineers were still alive, including Dr Tommy Flowers, and they were all enthusiastic about such a project. Work began in November 1993 to reproduce machine drawings from the photographs. (All the original drawings had been destroyed in 1960). All attempts at getting sponsorship for the project failed, and Tony Sale and his wife Margaret decided to put their own money into it in order to make a start since, in view of the age of the original engineers, time was of the essence.

By July 1994 all the gathering of information had been done and the construction phase of the project was inaugurated by His Royal Highness the Duke of Kent KG in Bletchley Park on the 18th July. The Bletchley Park Trust, of which Tony Sale is Museums Director, has kindly made space available and the construction has taken place in the actual room in H Block where Colossus number 9 stood in WW II.

Two years of hard work helped by an ever growing band of volunteers, including some members of the Computer Conservation Society, and some gratefully received financial donations has resulted in 90% authentic rebuild of Colossus which will now be able to demonstrate its code breaking feats of WW II.

His Royal Highness has kindly agreed to switch on Colossus at 10.00 am on Thursday 6th June 1996, an auspicious occasion since it is the anniversary of D Day for which Colossus helped to provide vital intelligence information.

For further Information contact Tony Sale on 01908 645001 or 01234 822788, or by fax on 01908 247381, or by email tsale_AT_qufaro.demon.co.uk