Date   : Thu, 05 Mar 2009 23:13:23 +0000
From   : jgh@... (Jonathan Graham Harston)
Subject: Recommended Master DFS version?

"Michael Firth" wrote:
> According to: http://www.adsb.co.uk/bbc/bbc_master.html
> and http://mdfs.net/System/ROMs/Filing/Disk/Acorn/versions
 
I've just updated that list with better version notes.
 
> It looks from the MDFS list like there are no bugs in the 2.28
> version, but presumably Acorn must have attempted to fix something
> in the 2.29 version?
 
In version 2.28 Tube OSGBPB transfers were trashed, which was
fixed in 2.29.
 
> Is there an accepted 'best version' of the DFS ROM that goes with
> the 3.20 OS ROM collection?
 
All the Master versions of DFS had faulty OSWORD &7F code when
trying to access double-density disks. The programmer had somehow
forgotten that the density select bit had moved from bit 3 of the
drive control register to bit 5. So, although the code is written
to allow drivenum+8 to specify double density, doing that on the
Master attempts to select DS2 as well as the specified drive.
 
Other than that I think I'd say 2.29 is the best version to use on
the Master, though I'll through in a plug for DFS2.29+Mse where I
have put a mouse driver in the spare space at the end of the ROM
and fixed the double-density select bug.
 
I have DFS2.24+Mse in my MegaROM replacement. The oft-quoted
"CLOSE#0 bug" in DFS 2.24 only affects bad programmers who try to
use CLOSE#0 when they should use *EXEC.
 
-- 
J.G.Harston - jgh@...                - mdfs.net/User/JGH
RISC OS Internationalisation - http://mdfs.net/Software/RISCOS