Film-Tech Forum ARCHIVE: Digital "Domesday Book" Decoding Takes 16 Years

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Posted by John Pytlak (Member # 331) on 12-02-2002, 06:52 AM:

Here's an article from the BBC News about the UK digital "Domesday Book" that stored historical images and artifacts on optical disks in the mid-1980's. Trouble is, it's taken two university computer teams 16 years to decode the obsolete Acorn Microcompter program to be able to again access the data and images stored on the disks! [Roll Eyes]

http://news.bbc.co.uk/1/hi/technology/2534391.stm

Posted by Mark Gulbrandsen (Member # 72) on 12-02-2002, 07:53 AM:

I think thats hilaroius!! Usually the BBC is much more careful about things technically. First off.....everyone can still remember the 1980's and all the "culture rich" data thats on the disk to begin with.....
Geez, all these folks had to do was look on E-Bay for one of the old computers! I fear that my uncle Rube musta been running that program......
Now that NASA data thats from the late 50's and early 60's might take that long to decode. The 80's, who cares about the 80's?
I hope that they remember to deposit the computers used to decode all this at the public records office as well.
Mark @ CLACO

Posted by John Moriarty (Member # 1153) on 12-02-2002, 09:18 AM:

One of my lecturers (Dr. M Richards) is also working on a related project (though it wasn't mentioned in the article). As I understand it, the software for the original was written in a programming language called BCPL (a typless precursor to C) which was developed by Dr. M Richards at Cambridge University. Unfortuneately the people who wrote the original code had a policy of destroying source code after a X years, and so only the compiled (for the BBC/Acorn computer) code still exists. Hence the task now is to decompile the BBC code back into BCPL, which could then be compiled for use on a more modern machine.

This of course serves to illustrate an important lesson; look after source code, especially for projects that might have historic significance.

John

Posted by Leo Enticknap (Member # 534) on 12-02-2002, 11:06 AM:

There has been a lot of misinformation kicking about over this BBC Domesday restoration project. For example, this article states that:

quote:
The trouble was that the discs could only be viewed using a special BBC Micro computer, which cost £5,000 to buy. Few were purchased, and only a handful are left in existence.

Wrong - it would run on a slightly modified Nimbus 286 PC under DOS as well. We had it at my high school on such a system. Furthermore, you can get working BBC Micros from just about any electronics junk shop or second hand retailer. Failing that, try the classified columns of the computer mags. It really shouldn't take a high-powered university researcher to get their hands on a working BBC Micro (the interface unit to the laserdisc drives which ran the discs is probably a lot harder to find, though, which might be what the author is really refering to). The computers themselves cost around £300, though I can believe that the whole system, including a lot of extra memory, a second processor, the interface unit and laserdisc drive would have cost around £5k.

quote:
'We have got a couple of rather scratchy pairs of discs, and we are confident we will eventually be able to read all their images, maps and text,' he said.

The discs were distributed to virtually every secondary school and public library in the country. Furthermore, I'd be astonished if the BBC hadn't kept the glass masters. It shouldn't be that hard to find an unscratched set. But finding a clean set is probably important, though. The Domesday disc consisted of four laserdisc sides, three of which were analogue CAV and one of which (it held video only) was CLV. Still images, moving images and audio were all analogue, with only the text content being stored digitally. The software basically told the laserdisc player's read head where to go, and didn't perform any data conversion.

Given that laserdisc drives are virtually obsolete and there's probably nowhere that still presses discs, I'd have thought they'd have had to digitise the content, which in turn would mean completely new software to play it back. That would surely make Acorn emulation irrelevant.