Date   : Sat, 21 Sep 2002 10:08:57 GMT
From   : pete@... (Pete Turnbull)
Subject: Re: BBC B with edge-connectors instead of IDC connectors?

On Sep 21, 11:33, John Kortink wrote:
> On Sat, 21 Sep 2002 09:43:16 +0100, Tim Fardell wrote:

> They aren't. They're just not fitted. Must be an upgraded
> model B where they 'forgot' to fit the three connectors.

Or a partial upgrade.  Companies like Watford sold individual kits to
upgrade specific parts, for those who wanted to do it piecemeal or who only
wanted one additional facility.

> DFS + NFS + Tube I/O code. Usually only fitted to machines
> that (have) run a 6502 second processor.

Actually, it was commonly supplied with 8271 disc upgrades for about the
latter half of the Beeb's sales life.

BTW, if there's actually a disc interface fitted (or an Econet interface)
the filing system will announce its presence as part of the startup
message.  If the appropriate interface is missing, the ROM will remain
dormant and not initialise.

> >Oh, one other thing - can I safely swap the ADFS ROM out of my Master
> >into the B? I assume I will need this if I want to use the disk drive on
> >the B?
>
> Probably not possible. The Master is largely backwards compatible
> with the beeb but it looks like you have a 8271 controller, not
> the 1770 that the Master uses. I don't think ADFS on a Master
> supports the 8271.

John's right, it won't work because DNFS is for an 8271 (only) and ADFS is
for a 1770/1772 (only).  In any case, I'm fairly sure the ADFS for the
Master is different from the ADFS for the B (different cnotroller
addresses).

-- 
Pete                                           Peter Turnbull
                                               Network Manager
                                               University of York