Date   : Wed, 10 Jan 2007 13:55:05 -0600
From   : julesrichardsonuk@... (Jules Richardson)
Subject: Domesday players and modern hardware

Ian Wolstenholme wrote:
> Not me, I've only ever connected up my VP-415 player to similarly
> ancient hardware!

Aha - I'll provisionally point a finger at Darren then ;-)

> Just before I decommissioned my Domesday Machine before Christmas
> I tried connecting the laserdisc player to a Beeb via the 1MHz bus
> with an Acorn host adapter but I didn't have any luck.  Although ADFS
> apparently mounted the disc, any attempt to catalogue or read the
> disc just gave Bad FS Map and similar errors.  This would suggest that
> the free space map/directory structure under VFS may be slightly
> different than ADFS, or maybe sector 0 isn't in quite the location that
> ADFS expects due to the other information on the disc.

Hmm, it's hard to tell. The only document that seems to discuss VFS at all is 
the Master AIV user guide - it says that VFS is based upon ADFs, but doesn't 
give a listing of what the changes/enhancements are. It does give a listing of 
VFS capabilities, but I'm afraid that I'm not familiar enough with ADFS to say 
what's altered. In various places it talks about ADFS compatibility, though...

According to the VP-415 manual issued by Philips, different "partitions" on 
the disc are handled as different SCSI logical units (LUNs), and I'm not sure 
what support ADFS has for that - it quite possibly hard-codes the LUN to 0.

> I'm pretty sure I've also had the VP-415 connected up to an
> Archimedes with SCSI podule in the past.  I can't remember exactly
> what happened but it would have been nothing to write home
> about otherwise I would have... written home about it!

:-) If the Archimedes controllers are dumb (i.e. devices are driven purely 
according to software config) then that could well work, as I think the basic 
read and write operations for the player are standard SCSI - it's just missing 
some of the frills expected on more modern devices.

> It's definitely been done with modern hardware though, either
> for the first "rescue" attempt (the "Loyd Grossman" one) or the
> more recent work which led to the web version.

Hmm - good point. I'll give Paul Wheatley / Adrian Pearce a prod as they 
should be able to give me info about what they did.

> As for the other discs you mention (Ecodisc, Volcanoes, Countryside)
> there will be data which could be archived.  They are all LV-ROM
> discs with a mixture of VFS data and video frames.

Yes, I thought they were - although Volcanoes appears to require application 
data to be loaded from floppy (but still presumably contains a VFS filesystem 
on the LV disc). Eco and Countryside possibly contain access software on the 
discs themselves (like Domesday) - or at least I've not seen any obvious 
floppies kicking around for them...

cheers

Jules