Date   : Wed, 31 Mar 2004 11:01:28 +0100
From   : jgh@... (Jonathan Graham Harston)
Subject: Re: Watford > Acorn DFS

Sprow <info@...> wrote:
> > Would I be right in saying that I could fit a Watford DFS ROM to my
> > master, having *unplugged the other DFS/ADFS present
> > and thereby read my old 5-1/4 double density Watford disks?
 
> I'd be almost 100% certain that this wont work as the Watford DFS will
> expect to find an 8271 disc controller (like the BBC micro has).
> The added confusion will come in that the Master 1770 interface is in a
> different place in the memory map and the control register is layed out
> differently too: so even that might not work.
 
It won't work. Having the misfortune to once work for Watfraud I had the
chance to look at WDFS's innerds.
 
Watford DDFS 1.5x (1770 version) looks for the 1770 controller and driver
control port in i/o in a completely different place from where it actually
exists in the Master. And, as Sprow points out, the control register is
laid out differently as well.
 
Your best bet is either a BBC B with 1770 controller, or a program that
runs on the Master and pulls the files off a DDFS disk.  There may be ones
floating around, if you can't find one I can throw one together.
 
> When writing DOSFS I decided to attempt to detect which machine I was
> running on, choose the base address and register layout based on that, then
> select the appropriate NMI handler based on that,
 
Ditto!  That's what HADFS does.
 
-- 
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/