Date   : Fri, 18 Feb 2011 10:42:31 +0000
From   : jgh@... (J.G.Harston)
Subject: *UNPLUG on a BBC B

Mick wrote:
> I've removed my 'Watford electronics shadow RAM' ROM from my model B as
> I got fed up of it intercepting calls on CTRL-BREAK resulting in my
> machine booting into Interword or Wordwise rather than Basic.

Can't you configure it to not do that? I'll dig out my manual and see
what it says.

> *ROMON  '&'x (insert???), *ROMOFF' &'x (unplug) and *XROMS to switch in,
> out or list ROMs.
> Can anyone recommend a utility ROM that will allow me to regain these 3
> utilities on my B? Perhaps there's any easy poke to do the same??

?(&2A1+romnum)=0 disables access to a ROM until the next Break by
removing it's entry in the ROM service table.

Many ROMs implement a permanent disable bit in the ROM workspace
pointer, so ?(&DF0+romnum)=&80 then Ctrl-Break will effectively
unplug them. DNFS uses two disable bits, &80 for NFS and &40 for DFS.

*ROMs is available on Utility Disk 2 at http://mdfs.net/Mirror/Archive/JGH
and http://mdfs.net/Mirror/Image/JGH

-- 
J.G.Harston - jgh@...