Date   : Fri, 27 Aug 2010 18:59:26 +0100
From   : jgh@... (J.G.Harston)
Subject: Does MOS 4.0 work properly in a full Master ?

paul aslin wrote:
> I'm considering making a new 1mbit rom using MOS4.0, and adding   
> ADFS, DFS and anything else needed. Point being it originally is a   
> 512kbit rom, so installing it as the top half of a 1mbit rom leaves   
> 4 unobstructed 16kbit rom slots.

Why MOS 4 exactly?

MOS 4.xx is a 32K MOS in ROM 15 and the C000-FFFF OS space.
ROM 14 and 13 can be replaced with absolutely anything. So,
if you put MOS 4 into an 8-bank ROM instead of the 4-bank ROM
it normally lives in, you've got ROMs 9,10,11,12,13,14 that
you can put absolutely anything in without worrying about
the MOS 3 code that overflows into ROM 9. That code is now
in ROM 15 by virtue of TERMINAL being chucked out.

I haven't got around to looking into it in detail, but are
you sure the Tube code is in MOS 4? I though MOS 4 chucked
away all the drivers for everything. I seem to remember
people ended up putting MOS 3 into Master ETs so they could
use the analogue and serial ports.

I'd recommend:

a patched DFS that allows you to do double-density access
from OSWORD 7F (eg DFS2.24+). In fact, I'd recommend DFS2.24+Mse
which has Mouse drivers in the spare space.
(see http://mdfs.net/System/ROMs/Filing/Disk/Acorn)

ADFS 1.53 - gives you access to IDE devices, ADFS 1.50 is only
useful if you really really want to use a SSCI hard drive.
(also http://mdfs.net/System/ROMs/Filing/Disk/Acorn)
Alternatively if you don't want any hard drive access at all,
and are happy with no Tube access, ADFS 2.00 which has *FORMAT
built in, at the expense of no Tube or hard drive support.

BASIC 4.32 or later. John Kortink has fixed a couple of bugs in
BASIC 4.32, I haven't got around to adding it to my archive yet.
(see http://mdfs.net/System/ROMs/Language)

What I call NewView - a patched View which has extended input
handling to let you enter PC-8 top-bit set characters.
(http://mdfs.net/System/ROMs/TextEd/ViewJ300 is ROM image,
http://mdfs.net/System/ROMs/TextEd for documentation)

That's 6 ROMS: MOS, UTILS, DFS, ADFS, BASIC, VIEW. Leaves two spare.
My MegaROM has ANFS and HADFS in it, bringing it up to 8:
http://mdfs.net/Info/Comp/BBC/SROMs/MegaROM.htm

For consistancy with other arrangements, I would also recommend:
if you include VIEW - put it in ROM 14
if you include ADFS - put it in ROM 13
if you include BASIC - put it in ROM 12
if you include DFS - put it in ROM 9

JGH