Tuesday, 28 January 2014

Still catching up. Summer 2013, so long ago…

Over the last few months of 2013, I started to relate our adventures in Canada and the USA, where we went for our bi-annual trip to visit cousin Kaybee in Canada and The Son (TS) and family in the USA.  I had to do this retrospectively because once we returned home we were incredibly and unexpectedly busy and Blogging went out of the window for some months.   

We had arranged the timing of our trip to the states last year, so that it would bring us back home just in time to go on my old firm’s reunion and so the next weekend after arriving home, we were off to Bletchley Park where we had all booked into a nearby hotel.  Originally Bletchley Park was a private house in some large grounds in Buckinghamshire not too far from London, Oxford and Cambridge.   Because of its location it became the secret establishment for the codebreaking branch of British Intelligence in 1938.  During WWII the teams there broke the German and Axis force’s codes regularly from 1940 onwards. By 1944 there were about ten thousand staff working on the site and it is estimated that the war was shortened by approximately two years by their work. It is now a large museum of early technology related to codebreaking and computing.

The original house at Bletchley Park
Click on any picture to enlarge it
The Germans used a device known as an Enigma Machine and all their top security military communications were encoded via one of these machines. 

A three wheel Enigma Machine

To decode a message, you needed another Enigma Machine and the settings for the source machine.  Both code books and Enigma machines were kept in great secrecy by the Axis forces but eventually an Enigma machine was captured by the Polish Underground and brought to England. The codebreakers were now in a position to decode the German’s messages and only needed the key to the settings used by the Germans.  This was changed at midnight every night and so every day the codebreakers had to work out what the new settings were.   Since there are 158 trillion different possible settings, this was impractical to work through all of them, but using a machine built to run through a range of possibilities and a great deal of intuition, the team at Bletchley managed. The machine, called the Bombe, was designed by the mathematician Alan Turin and it is an impressive piece of electromechanical engineering.  It consists of a bank of drums that could be interchanged and set up to imitate the possible Enigma settings.   

The front of the Bombe, showing the interchangeable wheels. It is as tall as I am.
The operators then worked through enough different settings against a received message to eventually produce legible German text when the settings were put into a captured Enigma machine.  A working model of the Bombe still exists which, when operating, makes the most astounding din as the wheels and rotary connectors spin round.  It took about thirty minutes to produce a result, but not every result was correct, so the teams worked continuously until they obtained a result. 

The back of the Bombe, with the inspection panel open
Whilst there were Americans involved, and the Americans did eventually capture a German submarine complete with an Enigma machine and code book, unlike the implications of the movie Enigma. Most of the donkey work was done at Bletchley and the decoding of the Lorenz machine, an even more complex encoding system than the Enigma, that was used by the German high command including Hitler was done exclusively at Bletchley.  They did have some help from the Germans for this machine, since a German operator re-sent a message without changing the codes, giving them a great deal of help in identifying how the Lorenz code was set up.
The much more complex Lorenz Machine used by Hitler
Some of the best brains from members of the Allied nations caught up in the war, all worked on the means of decoding and analysing encrypted messages and the first digital computer systems were developed there to speed up the process.   In those days and for several decades after the war, in the UK, the Post Office was responsible for all telecommunications around Great Britain and overseas where both wireless and telecoms staff were at the leading edge of technology. This was borne out by the fact that Colossus, the first ever digital computer system, was built by Tommy Flowers, a Post office engineer.   The only comparable level of advanced technology around at the time was radar. The first electro-mechanical system was not fast enough to keep up with the data being read off teleprinter paper tape, so Tommy Flowers designed an electronic machine to do it.   It contained 1,500 thermionic valves (tubes in the USA).
The reproduction Colossus, complete with bored operator

Some of the 1,500 valves on a panel at the back of the machine
In terms of actual active components in the Colossus, whilst 1,500 was an unprecedented amount of valves at the time when a radio would usually have four. Colossus was the most complex electronic device of its time.  Today, your average smart phone will have several billion active devices, that is transistors, the modern replacement for the valve. Even a bog standard phone will have several hundred thousand transistors in it and both kinds of phone are small enough to fit in your pocket, so Colossus was not very complicated by today’s standards, but it was both the first and the fastest for the time and very impressive.  
A selection of ancient valves
A short discourse here on language regarding the US use of the word Tube.  The Tube is something you ride in under the ground in London, also a tube is the thing a toilet roll is wound on; a valve is something that only allows something to flow one way.  A thermionic valve only allows electricity to flow one way…QED valve is the proper name for these thermionic devices.
The cylindrical red one on the left hand side is an EF50. After the war, these were sold off in their millions and for amateur radio enthusiasts they were a boon and were to be found in all sorts of equipment, both commercial and home made.  When a teenager, I managed to get hold of a box of around fifty or so and spent a happy few weeks using them as airgun targets.  They held together long after being riddled with pellets and so could be used time and again.  Glass valves, whilst exciting because they made a bang when you hit them as the vacuum imploded, only lasted for one hit.  

These made a great air gun target
Whilst Alan Turing was heralded as the brains behind the Bletchley team, and he was amongst other fields of endeavour, a brilliant mathematician, he was not the only smart cookie there and people like Tommy Flowers, Bill Tutte and Gordon Welchman, plus many others contributed to the overall success of the establishment.  Many were never acknowledged because of the intense secrecy surrounding the place. All staff, however humble their role, were sworn to secrecy on pain of death (literally).  It was not until after the 30 year rule lifted the secrecy from much of the work that took place there, that people were able to say what they had done during the war. Many were so ingrained in the spirit of secrecy that they never revealed what they did and took their secret to the grave.  One of the stories we were told by the guides taking us around was that they had two elderly visitors there once, who, when they saw the places where they had worked, only then discovered that both of them had been part of the Bletchley team during the war.  They had kept the secret even from each other during sixty years of marriage and it was a revelation to them both.
Another blast from the past for me, this was the kind of oscilloscope that we used in my college way back in the 1960s when I was studying electronics.   So heavy it had to be placed on a trolley
Altogether a very interesting place to visit, especially for geeks and technophiles like myself and my erstwhile colleagues and we lingered over the ancient technology much to the distress of TBH and the other wives, who soon discovered where the coffee and tea was served to rest their tired feet.
That evening we had a Chinese meal together.  The following day we had originally booked another night in the hotel in order to explore the neighbourhood.  Unfortunately we had a lot to do as a result of my late Brother in law’s death, so we cancelled the hotel room and returned home a day early to start sorting out his affairs.  This unexpected and unwanted task took care of the next six months.  


  1. Fascinating place. We went a couple of years ago.

  2. Erm.... by the way. You're over 70? Surely that's a typo!

  3. As usual, fascinating details! Love the story of the elderly couple! And yes, AJ, I can testify to the fact that he is over 70, but doesn't look a day over 50....at least the last time I saw him!