| The National Museum of Computing | |
| Coordinates: | 51.9985°N -0.7435°W |
| Established: | 2007 |
| Location: | Bletchley Park, UK SatNav MK3 6DS |
| Publictransit: | Bletchley Train Station |
The National Museum of Computing is a UK-based museum that is dedicated to collecting and restoring historic computer systems, and is home to the world's largest collection of working historic computers. The museum is located on Bletchley Park in Milton Keynes, Buckinghamshire.[1] It opened in 2007 in Block H – the first purpose-built computer centre in the world, having housed six of the ten Colossus computers that were in use at the end of World War II.
As well as first generation computers including the original Harwell Dekatron computer – the world's oldest working digital computer [2] – Mainframe computers of the 1950s, 60s and 70s, the Museum houses an extensive collection of personal computers and a classroom full of BBC Micros. It is available for corporate, group, school, and individual visitors.
Although located on the Bletchley Park 'campus', The National Museum of Computing is an entirely separate registered charity with its own admission fee. It receives no public funding and relies on ticket sales and the generosity of donors and supporters. The museum has its own cafe and gift shop. In 2024 it was awarded full accreditation as a Nationally-styled museum by Arts Council England.
The Bletchley Park estate was threatened with demolition and redevelopment in the late 1980s and early 1990s. It was saved in 1993 thanks to the efforts of the Bletchley Park Trust (BPT), which had been established in the previous year.[3] One leading member – and secretary to the Trust – was a scientist with electronics and computer engineering skills named Tony Sale (1931–2011). He had worked for MI5 and later at the Science Museum alongside Doron Swade on a series of projects to restore some of the Science Museum's computer holdings to working order.[4] Sale became the first curator of the Bletchley Park Museum, which in its early days was supplemented by more than a score of collections varying from WWII memorabilia to model railways. One of these centred around the history of computing and contained many historic computers, several of which were maintained in working order by enthusiastic volunteers, many of whom were members of the Computer Conservation Society.[5]
In 1993, Tony Sale and a group of volunteers started to rebuild a Colossus (a 'rebuild' as it contains parts from an original) in Block H. By June 1996 they had a prototype machine working, which was formally switched on by the Duke of Kent in the presence of Tommy Flowers who built the wartime Colossi.[6] When in 2004 Block H came under threat of demolition, Sale and colleagues were able to protect it by obtaining Grade II listed building status for it.[7] This led to the detachment of the computing collection from the Bletchley Park Trust museum, and the establishment in 2005 of the Codes and Ciphers Heritage Trust, which became the National Museum of Computing in 2007. Between 1994 and 2007 a group of volunteers led by John Harper built a working replica of a Turing-Welchman Bombe (used to help decipher Enigma–coded messages) in the BPT museum. This was relocated to Block H in 2018.
The exhibits on display in the museum represent only a fraction of the collection, but are chosen to tell the story of computing developments in Britain. There are a number of galleries which can be visited in a broadly chronological sequence, starting with the working replicas of WWII machines that were developed and used by Bletchley Park codebreakers.
This gallery tells the story of Cryptanalysis of the Enigma. Enigma machines were used by the Germans before and during WWII for sending secret messages. Alan Turing further developed, and Gordon Welchman enhanced, an idea implemented by Polish codebreakers, of a machine to assist in decrypting Enigma messages. This gallery houses a fully working replica of a Bombe machine, a working replica Enigma and various related artefacts.
The replica Bombe was built by a team led by John Harper following the release in 1995 to the Bletchley Park Trust of some 2,000 BTM documents and drawings relating to the Bombes that they had built during the war.[8] The replica is owned and managed by the Turing-Welchman Bombe Rebuild Trust, which provides and trains the volunteers who run and demonstrate the machine to visitors on a regular basis.[9]
Separate from the Enigma story is the less well-known endeavour of the diagnosing and deciphering of messages produced by the more secure 12-rotor Lorenz SZ teleprinter cipher attachments, which is told in these two galleries. The Tunny galley exhibits one of the very few Lorenz SZ42 machines still in existence — something that nobody in the Allied side saw until after Nazi Field Marshal Albert Kesselring surrendered in May 1945, shortly before VE-day.
'Tunny' was the name given to the messages, to the unseen cipher machine and to the British-built emulator of it. The gallery contains a reproduction of part of the original Lorenz listening station at Knockholt in Kent, with its multiple RCA AR-88 radio receivers,[10] pen recorders (undulators) and the sort of paper tape and teleprinter equipment that was used to record the messages and transmit them to Bletchley Park. Also on display is a working replica of a British Tunny machine that exactly emulated the Lorenz machine and a working replica of the Heath Robinson machine, the forerunner of Colossus.
The Colossus gallery houses the fully working rebuild of a Colossus Mark 2. During his work to save Bletchley Park, Tony Sale recognised the pioneering nature of the ten Colossus machines that had been designed and built during WWII to assist in breaking messages enciphered by the Lorenz machines. He and his team spent 14 years from 1993 in building this machine.
As its name implies, Colossus is a large machine which weighed five tonnes. It was designed and built for the single purpose of assisting with deciphering messages enciphered with the 'Tunny' machines. At the heart of the machine is a set of five counters that, for each transit of the looped paper tape containing the message, count the number of times that defined Boolean expressions deliver a specified value. These Boolean expressions were programmed by operating a panel of some 190 switches. The looped message tape would be run continuously, being read at 5000 characters per second. A cryptanalyst would specify different Boolean expressions for evaluation according to the results produced. With its 2,420 valves (vacuum tubes) and its programmability, the machine on display is a recreation of the world’s first large-scale, electronic programmable digital computer, albeit a special purpose, not a general purpose machine.
There are a number of related artefacts in this gallery.
This gallery continues the story of valve or tube-based computers and exhibits three large machines and many other related items. The three unique large machines are:
The original EDSAC (Electronic Delay Storage Automatic Calculator) was constructed by the Cambridge University Mathematical Laboratory under Sir Maurice Wilkes.[12] Wilkes had read John von Neumann's seminal paper First Draft of a Report on the EDVAC and attended the Moore School Lectures in Summer 1946. Starting in 1947, he designed and built the machine to serve a user community from many different departments of the university. The EDSAC ran its first programs on 6 May 1949 and is therefore claimed to be the first practical general-purpose stored-program electronic computer.
The vast increase in computing power that EDSAC and its successor EDSAC 2 supplied, contributed to the winning of three Nobel Prizes – John Kendrew and Max Perutz (Chemistry, 1962) for the discovery of the structure of myoglobin, Andrew Huxley (Medicine, 1963) for quantitative analysis of excitation and conduction in nerves and Martin Ryle (Physics, 1974) for the development of aperture synthesis in radio astronomy. All acknowledged EDSAC in their Nobel Prize speeches.[13]
It was used at AEA Harwell until 1957, when a competition was held for colleges to see who could make best use of it. The competition was won by Wolverhampton and Staffordshire Technical College (later becoming Wolverhampton University) and they gave it its second name of the WITCH (Wolverhampton Instrument for Teaching Computation from Harwell). The WITCH was used in computer education for over 15 years until 1973.
For a while the machine was on display at Birmingham Museum of Science and Industry, following which it was disassembled and put into storage at Birmingham City Council Museums’ Collection Centre. In 2009 the machine was spotted by TNMOC volunteers who recognised what it was, and made a plan to bring it to TNMOC for restoration in full public view. This was completed in 2012.[16]
HEC was based on an original design by Andrew Booth of Birkbeck College, London University. His design for a small scientific computer was adapted by Raymond Bird at BTM in 1951 to become a prototype commercial computer designed to work with the punched card equipment familiar to BTM's customers. The first production machine was delivered early in 1955, and the subsequent 1200 series of computers were highly successful.
The HEC and EDSAC had a huge bearing on the development of computing in the UK. In particular, EDSAC led directly to LEO, the world’s first computer to run a business. The WITCH had less influence on the development of computers but in the 1960s and 1970s, and again now, is a great educational tool.
Among the smaller items are several from the productive partnership between the Victoria University of Manchester and the electrical engineering company Ferranti. These include:
This gallery contains many machines of the 1960s, -70s and -80s and one or two from the 1990s. Many machines are in working order and include:
As well as being used in small to medium sized offices, it was marketed to price-sensitive, computing-intensive technical markets, like engineering and education, where colleges and universities used them for in both scientific and 'office' roles.[26]
The machine at TNMOC is on long term loan from Liverpool University who purchased it in 1968. After a period of non-academic use it was transferred to the Nuclear Physics Department around 1982 where it was used to digitise bubble chamber trace photos produced at CERN. Before it arrived at the museum, it had been in storage for over 25 years.
The museum's 2966 was donated by Tarmac who used it as a 1900, until it was decommissioned in 1999, due in part, to fears that it would be affected by the ′Millennium Bug′. Almost all large mainframes were broken up for scrap when they reached the end of their working lives, but Tony Sale, one of the founders of the Computer Conservation Society (CCS), who was directing the Colossus Rebuild, managed to persuade ICL to pay for its transport to Bletchley Park.
Nearly ten years passed before The National Museum of Computing was formed and the system was taken out of storage and set up in the this gallery in 2008. Unfortunately the damp conditions in the semi-derelict buildings that the machine lived in for so many years took their toll. The long and difficult process of restoring the system to working order has been underway since its relocation. The magnetic disc units for these machines require specially filtered and temperature-controlled air which is not available in the 1944-vintage Block H building. Instead, a solid-state device that acts as a virtual disc system was built. The configuration from Tarmac did not include any video terminals, but three original ICL terminals were acquired and restored. The machine is run as a 1900 under the George 3 operating system. Visitors can now use the terminals to play noughts and crosses against the computer, and to explore the twisty windy passages of the classic Colossal Cave adventure game.[28]
This small gallery is used for a variety short-term exhibitions. These have included:
This gallery exhibits a variety of items including:[29]
This gallery exhibits many of the familiar home and business computers of the 1980s and 1990s.[30] Visitors can play some of the popular home computer games of the time as well. On show are, amongst others:
Various substantial exhibitions reside here for periods of months or years.
This gallery covers a wide range of systems that were used in some way to simulate a reality. These include:
These are two adjacent and interconnected education areas. The Innovation Hub was equipped by Fujitsu as part of its Education Ambassador Programme. It contains an array of Fujitsu technology including tablets, hybrid devices, laptops and desktop PCs.
Next door is the BBC Classroom which contains a large set of working vintage BBC Micro computers. This machine was the winning design for the BBC’s Computer Literacy Project[32] and was first demonstrated by Acorn Computers in 1981. The resulting series of computers became a mainstay of British schools in the 1980s. More than 1.5 million were sold, and their rugged design ensured that they survived the school environment. This classroom is used for workshops, activities and talks for a wide range of groups including school and academic groups, families and special interest groups.
This gallery was sponsored by the UK's National Physical Laboratory.[33] It tells the story of how, in 1965, Donald Davies, a member of the team there responsible for building Alan Turing's Automatic Computing Engine (ACE) thought of the idea of a network of interconnected data terminals to access time-shared computers.[34] Rather than a large number of lines, each carrying only a small amount of data, his conception was for the data to be broken up into short messages in a fixed format, which he named ′packets′, with computer 'nodes' running software to switch the packets at high-speeds between physical circuits.[35] This concept of packet switching was first presented in public in the US at the inaugural ACM symposium in Gatlinburg, 1967, and in the UK at the IFIP Congress, 1968, in Edinburgh.[36] Davies' design of data communication for computer networks was adopted by ARPA, a research agency of the US Department of Defense and incorporated into its design of ARPANET, the forerunner of the Internet.[37] ARPANET's first link was established between the University of California and Stanford Research Institute in November 1969, by which time the NPL's packet-switched network was already operational.[38] [39]
The museum entirely depends on voluntary and corporate donations and admission charges. Fund-raising continues and donors have included Bletchley Park Capital Partners, Fujitsu, Google UK, CreateOnline, Ceravision, Insight software,[40] PGP Corporation, IBM, NPL, HP Labs, British Computer Society (BCS), Black Marble, and the School of Computer Science at the University of Hertfordshire.
The museum conducted a crowdfunding campaign in March 2018 to raise funds to build a new gallery for the Bombe.[41] The campaign raised over £43,000 via crowd-funding and an additional £20,000 via direct donations.
The museum secured £500,000 from the Post Office Remembrance Fellowship, conditional on the raising a further £150,000 in matched funding. This was for the restoration of the 80-year-old roof over the Tunny and Colossus galleries and the refurbishment of several museum spaces. In January 2023 they launched a crowdfunding appeal for the matched funding and raised sufficient for the work to start early in 2024.[42]
The Museum is normally open to the public 4 days a week: Tuesdays, Thursdays, Saturdays, and Sundays, from 10:30am to 4:30pm during the winter period, extending to 5pm during the summer months. Demonstrations and talks in the Bombe, Tunny, and Colossus galleries usually occur on the hour, with slight changes depending on the number of visitors. Guided tours operate at 2pm on Tuesdays, Thursdays and Sundays. Booking for tours is recommended as there are limited places.
See the museum website for admission charges, with concessions available for students, over 60s, and children (under 5s free). Annual tickets, offering unlimited return visits for all open days, are also available.
Department of Computer Science and Technology
. 13 September 2024 .