Date   : Wed, 03 Jan 2007 00:14:56 +0000
From   : jgh@... (Jonathan Graham Harston)
Subject: MOS ROM Structure

>Message-ID: <459ABD64.3040000@...>
 
Richard Gellman <splodge@...> wrote:
> space being tight, and socket 8 being used by ANFS for the Econet,
> my thought is to replace the built-in ADFS with the IDE-patched
> version (I don't plan to try and use an Acorn Winchester/SCSI hard
 
I have grand plans to replace ViewSheet and Edit as well and
replace View with an updated version ;)
 
> Is this a standard 128Kbyte ROM, or is there unusual/unexpected
> address decoding going on to map in the 16K OS ROM?
 
There's information at Andrew Banham's site at http://adsb.co.uk
I think you cannot get 28-pin 128K EPROMs, they only come in
32-pin packages and you have to build a simple carrier board.
 
> In what order are the ROMs laid out? I assume the paged ROMS are
> in the same order they appear in *ROMS, but where would the MOS
> ROM fit, I would hazard a guess at the end after ROM "15"
 
The MOS ROM is "ROM 8". In other words, the 128K ROM is laid out
as:
  00000 MOS
  04000 ROM 9
  08000 ROM 10
  0C000 ROM 11
  10000 ROM 12
  14000 ROM 13
  18000 ROM 14
  1C000 ROM 15
 
> As usual, I've Googled for info, but not come up with much (I
> suspect my choice of search terms are once again at fault), so if
 
It is one of those things where it is difficult to think of the
correct search terms. I only found Not The Abu Dhabi Ship Building
Company by accident.
 
-- 
J.G.Harston - jgh@...                - mdfs.net/User/JGH
United Kingdom Tercentenary : 1707-2007 : http://yr300.org.uk