August 21 – National Museum of Computing

Four Geocaching Challenges


Hello from Medieval Mosaic

In the morning we waited around the house as we were expecting a delivery of 1000 new exhibition brochures. They arrived at midday and we were just heading off for the day when I received an email from Julia at the shop at the cathedral saying that they had run out of booklets so we took a new box up to the cathedral. That was great timing.

When we first arrived at St Alban’s, Mike and I visited Bletchley Park and had a wonderful day. We realised later that there was also the National Museum of Computing at the same site and so have been promising ourselves that we would go back ever since and today is the day. It was a 45-minute drive up M1 before turning off to bypass Milton Keynes in a series of seemingly never-ending roundabouts including some rather exciting double roundabouts. So by the time, we arrived at the Museum we were definitely ready for a break from the traffic.

The National Museum is at the same site at Bletchley Park but is separately run. It is an independent charity housing the world’s largest collection of functional historic computers, including the rebuilt Colossus, the world’s first electronic computer, and the WITCH, the world’s oldest working digital computer. The museum enables visitors to follow the development of computing from the ultra-secret pioneering efforts of the 1940s through the large systems and mainframes of the 1950s, 60s and 70s, and the rise of personal computing in the 1980s and beyond.

Entry only cost us £5 each as we are concessions and we were there for three hours. I realised that there was a tour starting at 2 pm so paid a bit more and to join the tour while Mike continued at his own pace as he wanted to take photographs. I was very glad I took the tour as it was very informative. I was amazed at how clever these people were during WWII at their listening stations and their ability to decipher German messages and how this progressed to building the first computers in the world. Those early computing pioneers were real heroes.

The Tunny Gallery shows the entire World War II code-breaking process of the Lorenz-encrypted messages (Tunny) from signal intercept at the Knockholt receiving station in Kent to the production of the final decrypts on Tunny machines in Bletchley Park. These machines had various drawbacks including the use of paper tape which would intermittently shed and tear and also the terrific heat caused by the transistors but they did the job that they needed it to very successfully. It is hard to believe that the structure of the 12 rotor system of the Lorenz was worked out by British analysts three years before they even saw one. On display, they have a German Lorenz machine as well as a Lorenz teleprinter used for printing the messages. John Whetter and John Pether, volunteers with The National Museum of Computing, bought a Lorenz teleprinter on eBay for £9.50 that had been retrieved from a garden shed in Southend-on-Sea. It was found to be the World War II military version, was refurbished and in May 2016 installed next to the SZ42 machine in the museum’s “Tunny” gallery.

We saw the Colossus, the world’s first electronic computer which had a single purpose: to help decipher the Lorenz-encrypted (Tunny) messages between Hitler and his generals during World War II.  With Colossus, it is widely regarded as having shortened the war, saved countless lives and was one of the early milestones on the road to our digital world.

We also saw the Turing-Welchman Bombe, a working reconstruction of one of the most famous wartime machines. The Bombe is not officially open to the public at present as a team of volunteers is working on getting it going again after it was shifted from Bletchley Park to the Museum of Computing earlier this year. They are preparing for a challenge with a Polish team in a months time and so most of the time the doors are closed to give the team some peace and quiet. We were able to see the Bombe near the end of the day when they had finished their work and talked to the volunteers. You should see the wiring inside. It must be a mammoth effort to get it going again though they seem confident.

We saw the Harwell Dekatron aka WITCH computer, the world’s oldest working digital computer from 1951, and the ongoing reconstruction of the 1949 EDSAC, the computer that transformed research. The Witch was working away at a programme working out the square roots of numbers. It was wonderful to see this historic computer still in working condition. After WWII an English university went on to develop the computer and as it was part of a teaching institution the systems and parts were not patented but were shared which allows our free use of computer systems and hardware today.

The museum has a huge variety of early mainframe computers some of which still work. It was amazing to see how much miniaturization has taken place. They had a huge round metal disk with a diameter of about 3 feet which held 4 Mb each side. They also have a disk drive the same capacity of that which went into space with the Appollo flights. We also saw the use of magnetic tape for storage. The spinning backwards and forwards is the computer finding the bits of information that it needed. The Museum’s largest computer, the huge ICL 2966 of the 1980s, is coming back to life and there is a 1950’s Marconi TAC, 1960’s Elliotts and a 1960s IBM 1130.

There were also display cabinets holding many types of slide rules and things like the abacus and log tables. Many in the group remember using slide rules including me but couldn’t remember how they were used but it soon comes back to you. Mike and I still have our slide rules at home and our log table books, not to mention our first Amiga Computer with all its floppy disks full of programmes. There were slide rules for all different uses. One was for builders to be able to work out how much timber they needed. There was even one sinister slide rule to use in the event of a nuclear bomb hit to work out how long until you could safely come above ground and how long the fallout would last. Yuk!

In the next wing of the building, you start to get to the part of computing that we are more familiar with examples of the early teleprinters, calculators, computers, portable computers, mouse, etc. One of the most interesting was a mechanical pocket calculator named ‘The Curta‘ designed by Curt Herzstark while he was an Austrian prisoner of war in Buchenwald. There were examples of Addiators and a Muldico calculating machine.

There was a timeline of the computer programming languages and their creators including FortranAlgolCobolLispBasicPascalCAdaVisualBasicHTMLJavaPythonRuby and Javascript. There are examples of early computer games which visitors can play. There was also a display of a training programme for airport control which is capable of throwing all manner of problems for controllers to handle. There is a schoolroom where children can try out basic programming as well as newer games including an Augmented Reality headset for visitors to try. It was great to see the development of this as Steven, our son worked on early AR experiments while he was at university. The AR headset and program was in great demand.

The last room was all about the development of the internet. It is amazing to think of this development from the early computers to today where everyone carries around their computers every day in their cell phones and Ipads. We are truly blessed to have seen this amazing change in people’s lives during our own lifespans. We had a fascinating afternoon and we were very pleased that we came.

Rather than head onto the main roads at peak time on, we drove to Little Brickhill which was very close by. On the way, we stopped at the church in Fenny Stratford. We collected all the numbers while parking on a wide pavement. Then a guy who belonged to the church came to talk to us about the church and the fenny poppers which he showed us. St Martin’s church is known as the home of the Fenny Poppers; six small ceremonial cannons which are fired annually on St Martin’s Day (11th November.) The poppers each weigh about 19 pounds (8.5 kilos).

We went to look for the cache but it wasn’t there. Then we noticed that this cache had been disabled. I wish geocaches would not come up on my GPS when they is disabled. Anyway never mind. Maybe we will get another opportunity.

There was a church micro at St Mary Magdalene church in Little Brickhill which we found but I knew that the name meant something else to me. Then I realised that in a woods surrounding the golf course nearby was a series of geocaching challenges which we have qualified to find. So we went to find the finals. The first was the ‘500 Trackables’ challenge and we have logged 720. Then the ‘Iconic’ Challenge where you had to have found caches with 11 different icons. We have done 11 in one day and have actually found 13 different icons. For the ‘Alpha-Numeric’ Challenge, you had to have found thirty-seven caches, each one starting with a different letter of the alphabet (A to Z) and a number from 0 to 10. The fourth challenge we had completed was ‘Reviewing the Reviewer’ where you need to have found caches that have been published by twelve (or more!) different Reviewers and we have 53. There were actually two more challenges which we had qualified but we were starting to flag after such a busy day so went home very happy.