Date   : Fri, 20 Sep 2013 11:41:14 +0100
From   : percy.p.person@... (Ed Spittles)
Subject: Early BBC MOS EPROMs

Looks like OS 0.1, according to
http://www.stardot.org.uk/forums/viewtopic.php?f=3&t=4542

If it doesn't work, it might even be a pre-production version.

Cheers
Ed



On 20 September 2013 10:36, Dave Curran <bbc@...> wrote:

> I've been going through a pile of used EPROMs I got on ebay a while ago
> and have found 4 2732 EPROMs labelled 'C', 'D', 'E' and 'F'. It was mainly
> 27128s in the box, and that was what I was after at the time. I remember
> looking at the time to see if there were any marked 'A' and 'B', so I just
> assumed they were an incomplete set from something and put them to the back
> of the box.
>
> Now I'm after some 2732s I thought I'd check what was on them. The
> following string stands out:
>
>  :
>  :   (c) 1981 ACORN Computers Limited
>  :
>  :
>  :   BBC Microcomputer Machine Operating System (MOS)
>  :
>  :
>  :   Change record:
>  :   032 12-Aug-81 PB     Swop '_'
>
> Above that it says OPT MOS70.
>
> I then twigged that there probably wasn't an A and a B, and the CDEF must
> refer to C000-CFFF, D000-DFFF etc. and I remembered reading about early
> BBC's having the OS on 4 EPROMs. I think there is a way of arranging the
> jumpers to set the board up for this (may just have been the early
> issues?). Anyway, I was interested to see if they worked so rather than
> work out the jumpers, I combined the 4 images onto a 27128 and put it into
> a BBC in place of OS 1.2.
>
> It beeped (but the beep didn't stop) and the screen showed
>
> BBC Computer 32K
>
> No language ROM?_
>
> So I put in back the BASIC ROM and tried again
>
> BBC Computer 32K
>
> BASIC
>
>
> ?_
>
> No response from the keyboard and the beep doesn't stop, so I presume some
> of the device addresses or OS entry points might have changed.
>
> Just wondering if there is a copy of this in an archive somewhere or if
> anyone is interested. Doesn't seem to be usable on the issue 4 board I
> tried it on, but might be of interest to someone?
>
> The ROM ends with
>
> (C) 1981 Acorn Computers Limited.Thanks are extended to the following
> people, companies and locations, contributors (among others too numerous to
> mention) to the development of the BBC Computer:David Allen,Bob Austin,Ram
> Bannerjee,Paul Bond,Allen Boothroyd,Cambridge,Cleartone,John Coll,Computer
> Laboratory,Chris Curry,Designers of the 6502,Jeremy Dion,Tim Dobson,Joe
> Dunn,Paul Farrell,Ferranti,Steve Furber,Jon Gibbons,Lawrence Hardwick,Dylan
> Harris,Hermann Hauser,Hitachi,Andy Hopper,ICL,Martin Jackson,Brian
> Jones,Chris Jordan,David King,David Kitson,Paul Kriwaczek,Peter
> Miller,Arthur Norman,Glyn Phillips,Mike Prees,John Radcliffe,Peter
> Robinson,Richard Russell,Kim Spence-Jones,Graham Tebby,Chris Turner,Adrian
> Warner,Wilberforce Road,Roger Wilson,Alan Wright.
>
> Which seems to differ slightly from the message in the OS1.2 ROM:
>
> (C) 1981 Acorn Computers Ltd.Thanks are due to the following contributors
> to the development of the BBC Computer (among others too numerous to
> mention):- David Allen,Bob Austin,Ram Banerjee,Paul Bond,Allen
> Boothroyd,Cambridge,Cleartone,John Coll,John Cox,Andy Cripps,Chris
> Curry,6502 designers,Jeremy Dion,Tim Dobson,Joe Dunn,Paul
> Farrell,Ferranti,Steve Furber,Jon Gibbons,Andrew Gordon,Lawrence
> Hardwick,Dylan Harris,Hermann Hauser,Hitachi,Andy Hopper,ICL,Martin
> Jackson,Brian Jones,Chris Jordan,David King,David Kitson,Paul
> Kriwaczek,Computer Laboratory,Peter Miller,Arthur Norman,Glyn Phillips,Mike
> Prees,John Radcliffe,Wilberforce Road,Peter Robinson,Richard Russell,Kim
> Spence-Jones,Graham Tebby,Jon Thackray,Chris Turner,Adrian Warner,Roger
> Wilson,Alan Wright.
>
> Thanks,
>
> Dave
>
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