Mainframes & large systems

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

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 iPhone 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.
• and PDP 11 based Air Traffic Control system and PDP 11 based Blacknest monitoring system in other galleries

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 was used as a monitoring system for a nuclear power station. It gave sterling service for many years from its installation in the early 1960s to finally being decommissioned in 2004 - that's over 40 years! That is amazing considering the technology being used. It was kindly donated to the museum.

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 lead by John Sinclair, and the machine has been running with little need for attention for many years. It has recently had two upgrades: The addition of a Calcomp drum plotter and some additional input/output features. As well as the system on display here at TNMOC, John has also restored and maintained an 803B system for the Science Museum in London.

As with any good system we have it working hard each Saturday. 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 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.

IBM 1130

The IBM 1130 was launched in 1965 and was the first system IBM designed to work in an office environment. It was still in use in the early 1980s with over 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 came from Liverpool university and is on a long-term loan, and according to some paperwork found with the system, it was used in the Nuclear Physics department. Before it arrive at TNMOC it had been in storage for over 25 years and it took a team of volunteers over 3 years 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.

ICL 2966

Since the advent of the PC, the imminent demise of "big iron" has been predicted, but they are still here - alive and well in the cloud.

The Museum's largest computer, the huge ICL 2966 from around 1985/7, is coming back to life. It 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. What is more surprising is that we did not actually have room for all of it, it fact what you seen on display is less than half of its original size..

This system uses a lot of power - you can't run this from a 13A plug - so we had to have a separate mains supply fitted to enable the restoration to continue. 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, it still gets hot. At least we know that on cold winter days the large systems gallery will probably be the warmest room in the museum (assuming our resident ICL Mr Fixit can get it going!)

The system itself was used up until 1999 at 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.

The long and difficult process of restoring the system to full working order is now well under way. We are lucky to have help and advice from the ICL/Fujitsu engineer who maintained the system during its working life at TARMAC and actually decommissioned it.

Restoration work takes place on most Saturdays.