Date   : Fri, 12 Jan 2001 23:56:18 +0000
From   : jgh@... (Jonathan Graham Harston)
Subject: Re: VFS: (BBC Video Disk) : Doomsday Project

Ben Newsam <ben@...> wrote:
> >Could somebody with a working VFS do:
> >*VFS
> >A%=7:PRINT~USR!&21E
> I fear that it will have to be on a fully working system with a disk
> player as well, because all I got was "Turn interlace on", and when I
> did, it locked up before the prompt came up.
 
As in *TV,whatever?
 
> Interstingly, it has added "VFSDir", "VFSNoDir" and "NoEject" to the
 
The VFS equivalents of *Config. DIR and NODIR.  Presumably NoEJECT
prevents the little kiddy-winks from popping the lazerdisk out of the
machine and putting their grubby little paws all over it ;)
 
> *configure list, and attempts to boot up in VFS on CTRL-Q/BREAK and
> CTRL-L/BREAK.
> Does anyone know why my machine should lock up on CTRL-Z/BREAK?
 
Ctrl-Z-Break starts up 1770 DFS in "8271 Emulation" mode.  Essentially, it
ignores some 1770 DFS calls, but specifically, hooks into OSBYTE to return
1 from Osbyte0,<>0, to make the computer identify itself as a BBC.
 
When VFS starts up, as with ANFS, it issues an Osbyte 0,<>0 to find out
what machine it is running on.  If it's not a Master (X=3,4,5) then it
issues an error, something like "Bad ROM" or "Bad OS".  On a Beeb an error
on Break causes the machine to enter a hung loop: .here:JMP here
 
-- 
J.G.Harston (JGH BBC PD Library) 70 Camm Street, Walkley, SHEFFIELD S6 3TR
jgh@...                - Running on BBCs & Masters with SJ MDFS FileServer
Z80+6502/CoPro+Tubes/Econet+SJ - - - - - - - http://www.mdfs.net/User/JGH/
                             Et In Arcadia Ego