Every now and again someone puts a Domesday machine on sale. Usually the description is a little vague, and often the goods on offer are incomplete. This is a very brief guide to these devices and their components.
Basically, the Domesday machine - or to be more accurate (since this was never the official name), a computer system built for the Domesday Project - is an early examples of British information technology; a fatally flawed attempt to create something not unlike a small version of Wikepedia using 1980s technology. The fatal flaws were that it was
- built around the 8-bit BBC Micro (or a horribly kludgy Research Machines MS-DOS computer with a lot of extra boards),
- used 12-inch laserdiscs as its main storage media - good for capacity, at a time when hard disks were horribly expensive, but it meant that it was always going to be a little slow, expensive and more importantly BIG,
- was released about a year too early for the programmers etc. and
- contained incomplete data. Finally,
- there was no online updating.
So what was the Domesday Project, and why did it need special computer systems?
Basically, the Domesday Project was an attempt at a comprehensive survey of Britain along the lines of the 11th-century Domesday Book. To be in keeping with the modern era, the results eventually took the form of a multimedia package which included maps, endless tables of statistics (mostly collected by schoolkids, so rather suspect, and most schools failed to return at least some of the statistics for their area), lots of short films, music, pictures, etc. There was a "point and click" interface, unfortunately based on joysticks and trackballs since mice were still in their infancy. It was a VERY good idea, just a long way ahead of its time.
The computer needed a special processor and ROMs and extra memory, the special track ball used to control everything was expensive and difficult to use, the laserdisc player was heavily modded for computer control, etc. etc. It worked reasonably well, considering these limitations, and was an extraordinary achievement for its time, but there was only one application available for it, and the market - a couple of hundred major libraries and colleges and a relatively small number of schools able to afford the £1200+ even the basic system cost - simply wasn't big enough for it to really take off. They sold poorly and the project eventually died. Nevertheless it was one of the first real attempts to build an interactive multimedia system, and for a long while probably the best. One important problem that later developed is that once it was released much of the data used to create the discs and write the program was simply discarded. Even so, it was an extraordinary achievement for its time and paved the way for many modern successors. The machines are important landmarks in the history of computing.
There's some variation in designs - the picture above shows the basic configuration of the machine, as supplied to schools, but some versions used a laserdisc player with removable caddies, some were based on Research Machines Nimbus computers (computers based on the Intel 80186 chip which ran a version of MS-DOS, had BBC-compatible graphics cards, but were not compatible with any other MS-DOS computer of the time), some added hard disks, etc.
The components that should be common to all versions are two laserdiscs, a laserdisc player modified for computer control, and a "precision" track ball or joystick designed for accurate movement of an on-screen pointer; the joystick version had a vernier-like control knob. The BBC version should include extra ROMs and memory; I'm not 100% sure of the extras needed for the Nimbus version, but I think it added an external controller box of some sort. You should be aware that the laserdiscs are useless on their own - the data was stored in a proprietary format that can't be accessed without the rest of the machine.
Working systems are now extremely rare and very collectable - but if you are thinking of buying one you are strongly advised to view before buying - try to see everything working including the laserdiscs, track ball or joystick, computer, etc. I'm only aware of one working machine accessible to the public, at the Computer Museum at Bletchley Park.
There are several web sites devoted to these machines - and recently the BBC put the original contents on line, with plans to start updating the project to improve coverage and update content
If you are interested in laserdiscs in other applications see my guide to this technology, player features, etc.
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