Old Photos circa 1986

These are some more old photographs circa 1986 including people and computers. If you click on an image you will see the fullsize image, to get back click the browser BACK button.

The theme is power, computers, heat dissipation.


The electrical power enters via the Low Tension Switch Room from two transformers that reduce the 11,000V supply to 240V in the LTSR. The right hand side supplied Claremont Tower and Claremont Bridge, whilst the left hand side supplied the Sub-Basement Computer Room. Interestingly the air-conditioning plants for the Computer Room were supplied from the Tower side. In the early days it was necessary to isolate the computer supplies from all other power supplies to avoid fluctuations.

Amdahl 5860

This is the power hungry beast, the Amdahl 5860 computer. It used Emitter Coupled Logic. The blue cabinet on the right is the Rotary Convertor. It used 240v 50Hz electricity to drive a motor. On the same shaft was a generator supplying 400Hz electricity to the Amdahl. The motor and generator were very heavy, about a tonne, which meant it had the momentum to power through power glitches.


With a mainframe computer came a Customer Engineer who was based on-site. This is Reg, who was employed by Amdahl. Behind him is the PDU (Power Distribution Unit) that sequenced the powering on of the components. If everything was powered on together the inrush of current would be too great.

Beyond him is the CPU (Central Processing Unit) with its doors closed.


This is the CPU with its doors open. On the left are four power supplies, and the big panel with the red warning triangle is the gate containing 40MByte of RAM.

To the right of the RAM is the "Stack" with its red ribbon cable connections. Below the Stack are six more power supplies.


This is a closer view of The Stack. You can find out more about The Stack HERE.


Banks of disk drive cabinets, 4 disks in each cabinet, about 1GByte per cabinet. These disk drives were reliable unlike the disks in the blue cabinets the engineer in the photograph below is repairing.


View from the other end of the computer room. Calcomp plotter foreground/right.

Under floor

Under the floor was a mass of cables. Power cables are black, channel cables connecting devices are grey, orange cables were mineral-insulated copper-clad cable connecting fire detectors and alarms, thin white network cabling, thin grey telephone lines, and so on.

The cluster of thick grey cables were connecting a bank of disk drives to two mainframe computers, the IBM 370/168 and the Amdahl 5860. The thinner grey cables were power on sequencing cables

Operator's console

The two machines on the right are operator's consoles. Behind them are magnetic tape drives, the second in use.

The Nimbus computer on the left is displaying the status of NUNET (Northumbrian Universities NETwork). It was a star network of LSI11 computers called "Nodes". The node at the bottom centre connected to the mainframe; connected to it were 4 other nodes in other buildings, connected to them other nodes, ...

The connections were copper conductors and the nodes were prone to damage during electrical storms.


Here is Lyn Greenwood standing by three racks that were the heart of NUNET. I can see two PDP11s and an LSI11 node. At the top right is a panel with 4 rows of lights and switches and 3 big buttons, (red/green/yellow). This was a home-made channel interface that connected NUNET to an Amdahl channel.


This is an engineer repairing a Memorex 3683 disk drive. Find more about it HERE.

System Engineers

Lyn Greenwood and Quentin Campbell were software engineers (SEs) employed by the University.


Two more software people, John Aspden and Jill Foster in room M17.


Room M17 was a network room connecting the university to the outside world.


George Brown and Stuart Hay, network technicians, are in SB3 where multicore cables from telephone exchanges terminate and individual cables went off to telephones or modems connected to computers.


Here is Roger Broughton, Operations Supervisor, also in SB3. There the temperature was just right for brewing. On the wall behind him are telephone line termination boxes. In the rack are 9600baud modems.


This is the Plant B air-conditioning plant installed in 1974 for the IBM System 370/168.

There were two refrigeration units. There were two water circuits, a chilled water one encased in green coloured lagging, and a warm water one in naked plastic. To the right you can see a bit of the ductwork through which warm air was drawn by a fan from under the computer room floor. In the ductwork, a metal grillage was attached to chilled water pipes to cool the air down, and the cold air was returned by the fan blowing it above the false perforated ceiling.

The warmed chilled water was rechilled by passing through a heat exchanger that contained very cold refrigerant gas. This refrigerant was then compressed to a hot liquid that heated, by a heat exchanger, the water flowing through the plastic pipes. The plastic pipes went to the top of Claremont Tower where the Cooling Towers were. There the water was cooled by evaporation to the atmosphere and returned to be rewarmed.


This is the chilled water pipework behind ducting, complicated because the 370/168 needed not only chilled air to the computer room but actually chilled water to the CPU. The chilled water in the CPU either went through heat-sinks which hot components were mounted on or through heat exchangers that cooled the air being blown through the CPU.

The two people are Jeffrey Craig and Kevin Renney, technicians, who amongst other things looked after the air-conditioning plant.

Cooling Towers

This is Kevin again, up at the cooling towers. Behind him is a black fan that sucked air from the cooling tower. The air entered the tower through a pack of corrugated plastic sheeting over which the warmed water from Plant B cascaded down, delivered via the black insulated pipes. It was warm water in the pipes so should not freeze, but if the plant was shut down in very cold weather it might freeze.

Water Treatment Plant

At the top of Claremont Tower next to the Cooling Towers is the Water Treatment Plant room.

The cooling towers evaporated water to dissipate heat from the computers. This evaporation increased the concentration of dissolved solids which would precipitate out and block up the system. So periodically fluid was drained off the system to reduce the concentration of solids. Whilst this happenened, a ballcock in the bottem of the tower opened a valve to release treated water from a lagged tank, the edge of which can be seen on the right. Mains water entered the plant from out of sight on the left and went through the blue cylinder on the left where it was softened. From there it went to the green lagged tank on the left where Kevin is recording some test results. From there it is pumped to the lagged tank via an injector connected to the liquid in the white tub. The liquid in the white tub was biocide to kill algae that could grow in the warm water and block the water system.

Another major problem with this sort of cooling tower system was Legionnaires' disease spread by water droplets from the cooling towers. So twice a year the sytem had to be drained and refilled with a mixture of bleach and water, circulated for a while to kill the bug, then drained and refilled with fresh softened biocided water

Hence the need for technicians to maintain the plant. They also cleaned water filters and replaced air filters.