Mainframes arrived in the 1950s. They are still with us!

Now refurbished and re-opened in April 2019

Whenever families with children visit, they are always amazed just how big the systems from the 50s, 60s and 70s really were. Their only knowledge of computing might be the PC or laptop they have at home, or the smartphone in their pocket (which has many times more processing power than all the systems on display). We have many visitors with memories of working with these machines and they are usually amazed that we have them working!

There are:

  • A Marconi TAC from the late 1950s

  • Two Elliotts from the 1960s

  • An IBM 1130 from the 1960s

  • An ICL System 25 from the 1980s

  • An ICL DRS6000 from the 1990s

  • And the monster ICL 2966 from the 1980s


TAC - Transistorised Automatic Computer

Dating to around 1958/60 this is one of the more unusual systems we have on display. Contained within four large cabinets and a control desk, it was one of the first transistorised computers made in the UK. Ours, one of only 2, was used as a monitoring system for the Wylfa nuclear power station in north Wales. It gave sterling service from its installation in the early 1960s to finally being decommissioned in 2004 - a period of over 40 years! It was kindly donated to the museum by Wylfa.

The system is currently maintained by Steve Kay.

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National Elliott 803B

This is a fully functioning machine from around 1962 which, when it was donated to the museum, had spent about 15 years in a farm barn. The restoration was originally lead by John Sinclair, and for the past few years, maintained by Peter Onion. This machine as one of the first that the museum acquired and has been been running with little need for attention for many years.

As with any good system we have it working hard each Saturday and some weekdays. Members of the project team keep their programming skills sharp by developing programs for the 803 using the original software tools. These programs play music, draw graphs on the Calcomp plotter or solve mathematical problems. One recent program calculates the cost of a shopping list in pounds, shillings and pence (£sd, the UK's currency pre-decimalisation in 1971). This is a far cry from its original use for planning bakery delivery routes or accounting, but it does allow the system to be shown working and in doing so ensures its continued operation.

Two fully operational Elliott machines; 803B and 903 are on display at TNMOC.

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Elliott 903

The system was donated by Oliver Harlow, after his old school no longer had a use for it. O11y, as he was known, was a well respected volunteer at TNMOC, a funny and somewhat eccentric character who sadly died in 2018 and is missed by everyone who knew him. The system is dedicated to his memory.

The system is now maintained by Peter Williamson and Terry Froggatt and can be seen running most days.

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IBM 1130

The IBM 1130 was launched in 1965 and was the first system IBM designed to work in an office environment, as it did not need expensive air conditioning like its earlier models, and due to its small size and cheaper purchase/lease price. The system

It was still in use in the early 1980s, with an estimated 10,000 systems believed to have been built during a working life spanning nearly 20 years. As well as being used in small to medium sized offices, it was also used extensively in colleges and universities for both scientific and 'office' roles. The one currently running at TNMOC is on long term loan from Liverpool University where, according to some paperwork found with the system, it was used in their Nuclear Physics department. Before it arrived at TNMOC it had been in storage for over 25 years and it took a team of volunteers over 4 years (mainly working on a Saturday) to get it operational again. It is one of only 4 known working examples in the world, with 1 in Germany and 2 in the USA.

The system restoration was lead by and is currently maintained by Peter Vaughan, and the system can be seen running most Saturdays.

ICL 2966

The huge ICL 2966 from 1984 is by far the largest system we have on display at the museum, taking up almost a third of the floor space in the Large Systems Gallery.

This system uses a lot of power - you can't run this from a 13A plug - so we had to install a dedicated mains supply before restoration could begin. It also generates a lot of heat and would normally be in an air-conditioned room. As we could not fit out the whole gallery with air conditioning, we designed a large fan-assisted air venting system fitted to the top of the main cabinets to direct the hot air out through a window. Even so, on cold winter days the Large Systems Gallery is the warmest room in the museum!Our system was used up until 1999 at the construction company TARMAC, who after having decommissioned the system, donated it to the museum where it was put in storage. It was not until late 2007 that we had enough floor space to put it out on display and it certainly is impressive to see.

Whilst restoration of the core parts of the system is now complete, the work is far from over. We are lucky to have had help and advice from the ICL/Fujitsu engineer who maintained the system during its working life at TARMAC and actually decommissioned it.

The machine can be seen operating on selected days when the museum is open to the public.

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