Date : Thu, 04 Jan 2001 10:31:40 -0000
From : Andrew Chesterton <achester@...>
Subject: Re: VFS: (BBC Video Disk) : Doomsday Project
I don't know if the doomsday disks use the same storage formats as normal
Laserdisks, but if they do, you have a choice of two formats each with there
own storage capacities.
The capacity depends on how many 'frames' are stored per track on the disk
Constant Linear Velocity (CLV) disks have the greatest capacity because the
number of frames per track increases as you progress towards the edge of the
disk. A film such as 'Armageddon' fits on a single disk when stored using
this format. The problem is that 'freezing' a single frame does not give a
very stable picture.
Constant Angular Velocity (CAV) disks have less capacty because the number
of 'frames' stays constant accross all tracks. A film such as 'The Matrix'
takes both sides of two disks when stored using this format. The plus point
is that 'freezing' a single frame gives a perfect crystal clear picture.
As for GB storage capacity I have know idea.
Andrew Chesterton.
-----Original Message-----
From: Ben Newsam [mailto:ben@...]
Sent: 03 January 2001 18:09
To: BBC list
Subject: Re: [BBC-Micro] VFS: (BBC Video Disk) : Doomsday Project
In message <3A535808.2F40D4D5@...>, Paul Wheatley
<p.r.wheatley@...> writes
>
>Ben Newsam wrote:
>> Is it unfeasible to transfer the data onto CD-ROM and run new software
>> from Windows?
>
>Theres a few different issues arising there...
>
>Transfering the data to CD-ROM would probably be tricky due to the actual
>volume. There are approximately 200000 analogue pictures on the 2 discs as
>well as around 600 megs of digital data. Depending on what rez you digitise
>them at, that could be an awful lot of data.
I can understand that it would require quite a few CDs. My own interest
in it is in making the data available again, rather than preserving the
data or curating a working system. For the former purpose, there would
be no harm in compressing picture data using JPG format or similar,
which of course would be unacceptable for preserving "pure" data. What
was the capacity of 12" video disks? And did the Doomsday (Domesday?)
Project completely fill both sides of both disks?
>The principle of migrating the data to a modern system and writing a new
>interface to access the information is however a good one. Depending on
time
>available we may produce some new interface software.
Ummm, I *might* be willing to participate, if I can spare the time...
>Migration is one way to preserve some of the significant properties of the
>original, but it does not preserve all of them. Depending on who it is
doing
>the preservation and who they are doing the preservation for, an emulated
>solution *may* be far more ideal.
>
>As an example, in 100 years time a geography researcher would probably
scoff
>at having to use the original clunky interface to get at the valuable data
>entwined in the Domesday package, but a migrated version would suit them
down
>to the ground.
>
>Alternatively a sociology researcher (or even a computer software
historian)
>in 100 years time would probably be rather upset to find out that the only
>way the fabled early multimedia package produced on the BBC Micro had been
>preserved, retained nothing of the look and feel of the original
environment.
>For those users an emulated solution would allow the researcher the chance
to
>see an early user interface, and the computer historian would be able to
>examine the original software as it ran, perhaps even viewing the function
of
>the computer using the emulator's debugger, despite the fact that the last
>real BBC Micro had stopped working many years ago. Don't even get me
started
>on authenticity... These are all pretty tricky questions usually, with far
>more than one answer.
>
>Another issue is preservation of what we preserve. How do we ensure that
any
>work we do now (eg. a new interface written for windows) won't be obsolete
in
>another 15 years (or more likely 5 years)? This is something else we're
>working on, but I've already ranted on enough, so I won't attempt to tackle
>that here.
All very good points. I suspect, though, that CD-ROM format will not
disappear overnight, as there are rather more systems using it than
there were of the 12" videodisks.
By the way, do you know what model(s) are usable? I am looking around to
try to find one, but I don't know which models are suitable.
>Finally, the copyright issues are a major problem, particularly the OS maps
>which OS is unlikely to want accessable in a modern computing environment
>even if they are in bitmap form and 15 years old. So for the moment our aim
>is to preserve but not to allow access, until if/when we can sort out the
>IPR.
That's a shame.
Do the BBC not own all rights to the disks, then? If not, then who does?
Or is it all horribly complicated? I would have thought that they (in
the shape of BBC Enterprises) would be happy to see a reissue, as they
would probably sell more in a new form than they would have of the
original.
--
Ben