The Domesday System is rare and as time goes by, it becomes even rarer.
To be fair, it's always been rare because not very many were made or sold. The Domesday System was of special interest to schools, colleges and libraries but unfortunately these institutions didn't always have a spare £4,000 washing around to splash out on a Domesday Machine.
The passage of time hasn't helped. The BBC micro is a hardy old thing; a million Beebs of various forms were sold in Acorn's heyday and there are probably more Beebs in service than any other 1980s micro, but sadly posterity hasn't been quite so kind to the Laserdisc players or the Domesday discs.
Many players - not just the Domesday ones - have developed problems with the disc tray mechanism or the laser assembly or one thing and another and the discs themselves are susceptible to warping, splitting and cracking. Some would say Laservision was never the most durable technology in the first place.
So where does this leave us on the 20th anniversary of Domesday?
The Domesday Project had remained largely forgotten for most of the intervening two decades, until somebody came along and held it up as the prime example of "digital obsolescence".
What's obsolescence anyway? Count up the number of people still using a BBC computer launched in 1986 and people still using an IBM-compatible PC launched in 1986 - or even 1996 - and I know who's going to win!
But ironically, it was probably the best thing that ever happened to Domesday since it got people talking about the Domesday System and starting to do something about preserving it.
The end result is that the Domesday Project is probably as well-known now as at any other time since its launch.
That doesn't alter the fact that the number of working Domesday Systems in working order is very, very low.
Some worthy efforts have been made to preserve the contents of the Domesday discs, involving painstaking work on the part of a number of very dedicated individuals. For example, you can now view an emulated version of part of one of the discs online.
I thought I should be doing my bit for Domesday preservation.
To my mind, there are two elements to my Domesday Rescue.
First involves keeping the original Domesday hardware going as long as possible. Using the original computer system is an intrinsic part of the Domesday Project experience. I am lucky enough to own my very own Domesday Machine made up of original parts. Every now and again I fire it all up to make sure it still works and thankfully it's going strong.
Second is trying to copy the information on the Domesday discs onto a more sustainable media. There are two parts to this, the data and the video frames. As far as possible I always like to find an Acorn solution to an Acorn problem, so I have been using my ARM Co-processor, A5000 and MDFS to copy all the data from the Domesday Discs.
In preserving the video part of the Domesday Discs, I have had to place my faith in more modern technology, using my new DVD Recorder.
This section details the progress I have made in rescuing both the data and video elements from the Domesday Discs.