Just like the legs of the giraffe, our interests stretch a long way. Personally, I’ve been involved with computers since the early 70′s. The first computer that I ever worked on, as a trainee computer operator, was an ICT 1301. The Milk Marketing board here in the UK had 2 of these beasts in a room the size of a football field. You could get inside the cabinets holding the memory and controllers. Here is an extract of the Wikipedia entry for the ICT1301
“A typical 1301 requires 700 square feet (65 square metres) of floor space and weighs about 5 tons. It consumes about 13kVA of three-phase electric power. The electronics consist of over 4,000 printed circuit boards each with many Germanium diodes (mainly OA5), Germanium transistors (mainly Mullard GET872), resistors, capacitors and inductors. It contains no integrated circuits, though it does have a handful of thermionic valves and a few dozen relays which work only at human speed when buttons are pressed.”
It had a “drum” as a fast access device which lived alone in a massive cabinet. The drum could record 12,000 words of data. It also had 400 words of ‘reserved’ storage where the computer’s bootstrap program (called Initial Orders) was stored.. All programs were input from punched cards and data was stored on mag tape….no removable high speed storage devices in those days.
The operating console of the ICT 1301
That console had so many lights and switches that they’ve been used in a number of TV shows including Doctor Who and Blakes 7, as well as a couple of James Bond movies.
One great day ICL wheeled in a shiny new 1904A computer. State of the art, it had an operating system (George II) and removable disk drives (EDS 30′s) . These removable disk cartridges each held 30.8 mb of data and cost many thousands of pounds
An operator loads a removable EDS30 cartridge
The cabinets of the mainframe were just as big, but there was more inside them now.
Cabinets of an ICL 1900 series mainframe
It’s hard to believe that today’s desktop PC is 25 million times faster, and has 64 million times as much store as these early goliaths.
I feel so very lucky to have been born at a time of no world wars and everything connected with technology has developed at such an amazing pace.
I don’t work with mainframes these days but I do keep my hand in by building an occasional website, this is my car hire website.