Bletchley park

16.10.2012 17:43

I'm spending a few days in London and a this Sunday Jure and I visited Bletchley Park, the famous home of British code breakers during the second world war who cracked the German Enigma codes. It has been converted to a museum recently and is less than an hour of train ride north from London. I've heard some praise for the place and thought it might be worthwhile to check it out. We were not disappointed.

Entrance to Bletchley Park

The place is quite large, quite a bit larger than I expected. Not all of the former military buildings have been renovated though. Those that have been now house a collection about the happenings in Bletchley Park during second world war and the National museum of computing. A few other organizations also have a place there (like the National Radio Centre), but we ran out of time to check them out.

Sorry my decor is tired but a little more funding is required

The Bletchley Park collection includes probably just about every model of the Enigma machine ever made in Germany, plus a few that were modified during the decoding effort (one for instance has mechanical counters installed for statistical analysis). There's an impressive collection of other cyphering machines from all over the world as well, although I missed a bit more thorough description of their operation.

Lorenz cypher machine

All of this fades though in comparison with the centerpiece of the collection - the replicas of code breaking machines that were originally designed and constructed in this place, and later destroyed after the war to conceal the progress British cryptographers have made from the rest of the world. It shows incredible effort made by retired engineers that dedicated years of their life to painstakingly rebuild old machines, often reinventing parts and procedures for which no documentation could be found.

Back side of the Bombe machine replica

The first replica, a Bombe, is an electromechanical device that basically did an exhaustive search for an Enigma key given a known plain text. It's a wonderful missing link between computers and steam engines. While long strands of wires on one side would fit perfectly well in a backside of a Cray, mechanical insides are made with the best practices of steam engine technology, full of sprockets, cam shafts threaded with thin copper tubes supplying lubricating oil, slowly dripping into pans below.

Inside of the Bombe machine replica

There is also a nice tribute to Alan Turing, his life and work, including the official apology from the British government for his wrongful prosecution that led to his suicide.

Statue of Alan Turing in Bletchley Park

The other replicated machine, the first electronic computer called Colossus, was an even larger effort and supposedly included a public call for old equipment using vacuum tube to harvest for usable electronic components. It's housed in the same building that housed the original and has been tested by decoding a message encrypted using one of the preserved Lorenz encryption machines.

Colossus machine replica

The Colossus is also where the Bletchley Park collection touches the Computer Museum one. That one focuses on the history of computing in Britain and goes from the WITCH computer (first time I heard of a Dekatron tube) to the modern age and is much too large to go into any detail here. It includes everything from big main frames to home microcomputers, with the BBC micro having a prominent place. As with the Bletchley Park collection, it's staffed by engineers that will gladly enter into a lengthy debate about this or that tiny detail of the machines they lovingly care for.

HP 250

So in conclusion, Bletchley Park was definitely worth a visit and I wouldn't mind visiting it again on occasion, as one day just wasn't enough to go into any detail when examining all the exhibits.

Posted by Tomaž | Categories: Life


Skoda, da nisi obiskal pred kratkim odprt NRC s strani GB radioamaterjev. Jaz to planiram pri naslednjem verjetno jubilarnem 50. obisku Londona od leta 1970.

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