Earlier this year I wrote about Controlling the Scottish electricity grid in the 1980s and have since found some more information.

I found, scanned and uploaded some brochures about the grid control centre to the internet archive: SSEB Grid control brochure 1972 and the 1981 revision: SSEB Grid control brochure 1981. I also uploaded SSEB: Your electricity - a corporate video from 1987 that I found on a VHS video tape.

I was interested to find another brochure, which I also scanned and uploaded: SSEB Cathcart computer building. This describes a new building, specially designed to house the mainframe computer which ran the company.

I'm glad I didn't have to build a special building when I bought my laptop.

The brochure shows that the Dual ICL 2972 computer had:

I don't know how much storage this computer would have had, but the centre for computing history says:

"A bank of 5 EDS200 disk drives similar to ours would hold 1GB of data"

This suggests that the 17 drives (which presumably took up a chunk of this building) could hold around 3.4Gigabytes of data.

I found a model summary at Ancient Geek. The 2972 isn't listed, but the 2977 (of 1981) says "Machine cycle time: 113 nanoseconds" which is roughly 9MHz.

A bright pink child's camera which I found online for £7.89 would likely have similar amounts of RAM and storage, but much more processing power.

Yet this computer is reported to have carried out:

Can you imagine if an IT consultancy company today said "We'll run your whole company on a child's bright pink £8 camera"? Yet it was possible then…

I think it would be a fun art project to clear the building and have nothing but this tiny camera in the building, running the whole company. Nothing but space, and a tiny object in the middle with a cable radiating from it.

What of the building now?

It looks as though the SSEB headquarters were at Cathcart House, 42 Spean Street, Cathcart, Glasgow, with the computer building next door.

After privatisation SSEB become ScottishPower who look to have moved headquarters into the centre of Glasgow - so I assume the Cathcart site became vacant.

I can't find a huge amount of information online, other than this property brochure showing the rather splended headquarters building (apparently a former Victorian mill). It looks as though the building has now been converted into luxury flats and the computer building cannot be seen.

I'm the kind of person who would rather like having a mainframe computer in their back garden, but I think we're few and far between. I think it's unlikely to have been a consideration for the property developers so it's likely that the 1970s building may sadly have been demolished.

I hope that uploading this brochure preserves a tiny part of history.

See also

The ICL 2900 Series; J.K. Buckle (At ancientgeek.org) - a textbook describing the architecture of the computer.

There is a good amount of technical information about the computer and its operating system at ancient geek. There is a photo of what is presumably a similar computer - the 2976, from 1975 and wikipedia has some information. The grid control brochure shows an ICL 7500 terminal on the front cover, which was likely linked to this mainframe.