Date : Mon, 27 Apr 2009 11:30:49 +0100
From : bbcmailinglist@... (Ian Wolstenholme)
Subject: A thought for Domesday
I wrote a chunk copier for the ARM7 during the back end of 2006 when I
was doing a lot of Domesday things for the 20th anniversary.
Because I was encountering many disc errors whilst doing the copying,
it also lets you copy from a particular point within a file.
It's for VFS to Econet but I'm sure it could be very easily adapted for
ADFS, it was all official OS calls and a lot easier than I thought it would
be to write.
There's some pictures of it in operation somewhere here:
http://www.BeebMaster.co.uk/Domesday/DataRescue.html
I think I've got nearly all the data, but it's all in 8MB or smaller chunks
on one or two MDFS hard discs in a special "Domesday slice" I made
for the purpose.
I'm not 100% sure I got every byte, there were that many disc errors
that it was a real toil towards the end.
Given that I haven't had the MDFS switched on for about 2 years it
might not be there any more!
The maximum Econet file size is 8MB. On BBC ADFS it's 16MB. RISC-OS
is more: I remember creating a 100MB file on my A5000 to check that
it could cope with file sizes big enough for me to reconstruct the chunks
on the A5000, but I haven't got round to doing that yet. Might be a job
for the 25th anniversary!
I think the Interlace error might be an incorrect *TV setting. Maybe the
copier you are using changes the settings of *TV.
Best wishes,
Ian
----- Original Message -----
From: Joel Rowbottom [mailto:joel@...]
To: bbc-micro@...
Sent: Mon, 27 Apr 2009 08:25:23 +0100
Subject: Re: [BBC-Micro] A thought for Domesday
Hi --
On 27 Apr 2009 00:18:03 +0100, jgh@... (Jonathan Graham
Harston) wrote:
> With any filing system you can copy the data off the laserdiscs, eg
> with *treecopy vfs::0 net::backup.domesday which I did back at
> Stirling, and forgot to keep a backup of.
I'm having some issues doing this tbh, mostly in the file DATA1 where it
dies at an as-yet-unknown place and I get Disc Error 03. The only way to
sort it is a ctrl-break, presumably because either the SCSI interface or
the LVROM is reset into an uninitialised state.
My next step on this is to write something (probably utilising the ARM7)
which will chunk the data off - then at least I'm not starting from the
beginning if it goes mad and can give the player a bit of a rest
occasionally. I have my AUG in my bag to read over lunchtime ;)
Another query: Have any Domesday-ers seen the 'Turn Interlace On' error and
know what causes it? As I'm not using the genlock I've just been plugging
the Master AIV's RGB output straight into a CUB monitor, I'm wondering if
there's some sort of error caused by the genlock because it's not having
any input across it. Reproduceable by doing *VFS from (say) CTRL-A-BREAK to
select ADFS, but if I CTRL-BREAK into the VFS then do *ADFS then back to
*VFS it works fine.
Jonathan: You might be able to answer this one, what's the maximum file
size on ADFS then?
Cheers
j
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