Date   : Wed, 04 Dec 2002 03:02:19 -0000
From   : "Richard Gellman" <splodge@...>
Subject: Re: DIGITAL DOMESDAY BOOK GETS NEW LIFE

Confession time.

There's a reason I havent done much work on BeebEm lately....

I'm sure Paul won't mind if I admit that I've been doing (most of) the
programming work for this project :)

So, the quick specs on the *modern* system are:

324 Mb Data Image
+ 54,000 frames per disc _side_ at 768 x 576 x 24bit each
+ 1k of Disc Shape info

= 67 Gb per disc side.

And its a little harder than you think, because we had absolutely NO
technical docs at all... Save for Acorn Application note 004, and the LV-ROM
command specifications.

For those wondering what the emulation comprises:

Standard 128K RAM/128K ROM BBC Master 128 with:
Internal 64K 65C102 Co-Processor at 3Mhz
Modified SCSI interface board - (Modified from Acorn Winchester Hard Drive
Host Adapter board)
SCSI Bus
LV-ROM Player with both digital data interface and video control interface
(both through vendor unique SCSI commands)
5-mode Video Mixer
22Khz Stereo Audio Mixer

So, not the easiest thing in the world to emulate ;)

-- Richard Gellman


-----Original Message-----
From: Majordomo List Manager [mailto:majordomo@...]On Behalf Of
Isabel & Robert
Sent: 04 December 2002 02:38
To: Thomas Harte; bbc-micro@...
Subject: Re: [BBC-Micro] DIGITAL DOMESDAY BOOK GETS NEW LIFE


> Which must make the first of my former secondary schools (All Hallows,
Aldershot) look
> stupid, because I browsed the Domesday discs there only around 10 years
ago.

And the person who got the Domesday system from eBay told me he has spent
quite some time browsing it recently, with practically no problems.
He must be looking most stupid of all... :-D  (...not!)

A typical press release exaggeration... it *was* a race against hardware
deterioration, but there is still a working number of those LD players
around.  The Beeb has been emulated for almost 10 years - no problem there,
and plugging in a virtual LD driver can't have been to hard.  The tough part
must have been "ripping" the digital and analogue data off the disc, and
storing it in a suitable fashion/quality readable by that driver.  And even
that sounds straightforward.

I'm curious as to how much data those discs comprise - anyone know?

> Is there any publically available way to browse the project now? Will it
be available on
> CD or DVD or whatever?

I hope so, but I've seen no indication to that effect, yet :-(


Robert