Bletchley museum treasures vintage tech

Bletchley museum treasures vintage tech

Summary: ZDNet UK took advantage of a recent visit to Bletchley Park to uncover some of the thousands of items of IT heritage that the National Museum of Computing has in store

TOPICS: After Hours

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  • Ferrite core memory

    Ferrite core memory
    Invented in 1955, ferrite core memory was the mainstay random access storage medium for mainframe and minicomputers throughout the sixties. It works by hundreds or thousands of tiny O-shaped ferrite rings — ferrite being a iron-containing ceramic — that can be magnetised when current passes through two wires threaded through their centre.

    This magnetism can be read back by another wire — the sense wire, which also passes through the core. However, to get this signal, the ferrite has to be demagnetised by a pulse of electricity through the first wires. Thus, once read, the ferrite has to be reset back to its original state. Density is low, with one bit per ferrite, but planes of core memory.

    When not being read, however, ferrites were non-volatile; you could switch a computer off overnight and turn it back on with memory contents intact. The first solid-state memory replacements for core store had huge batteries to try and replicate this behaviour, until it was realised that reloading off tape was almost always more sensible.

    Photo credit: Rupert Goodwins

  • Post Office modem

    Post Office modem
    Something of a mystery object, this is probably one of the first data modems used in the UK. With separate data modulation and demodulation units, together with a control unit and a power supply, this modem is as one would expect an FSK (Frequency Shift Keying) design, with two oscillators supporting two channels, one for data zero and one for data one.

    If this unit was designed to work over ordinary telephone lines, it will be no faster than 300bps. That seems plausible, as it seems to have an auto answer mode, which wouldn't have been needed on a leased line.

    However, any further information will be gratefully received. Data Modulator No. 9A has secrets yet to plumb.

    Photo credit: Rupert Goodwins

  • Psion Protea Prototype

    Psion Protea Prototype
    There's a huge story to tell about Psion, one of the UK's most innovative consumer electronics companies and one of the few that could outdesign anyone on the planet. Protea was the codename for the Series 5 PDA, which remains one of the benchmarks for elegance, functionality and plain fit-for-useness.

    Running an ARM chip from two AA batteries that lasted up to 20 hours, it had a half-VGA resolution backlit greyscale LCD and an utterly charming slide-out keyboard that, in the opinion of many, has yet to be bettered in anything this size. The operating system, EPOC32, became Symbian, and came with built-in spreadsheet, word processing, database, diary and contact management.

    It was never actually produced in yellow. Shame.

    Photo credit: Rupert Goodwins

Topic: After Hours

Rupert Goodwins

About Rupert Goodwins

Rupert started off as a nerdy lad expecting to be an electronics engineer, but having tried it for a while discovered that journalism was more fun. He ended up on PC Magazine in the early '90s, before that evolved into ZDNet UK - and Rupert evolved with them into an online journalist.

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  • Always pleased to see news about Bletchley. I was going to visit (again) this holiday period but the weather was too good!