Date   : Sun, 15 Apr 2007 01:00:42 +0100
From   : jgh@... (Jonathan Graham Harston)
Subject: BBC B progs on a B+128k - any known problems?

>Message-ID: <4ecc11c792info@...>
 
Sprow <info@...> wrote:
>    Jon Ripley <jon@...> wrote:
> > IIRC (Ctrl+)Z+Break selects a special compatibility mode that allows
> > greater compatibility with software that expects a BBC B.
> 
> You're quite right, it works by mangling the commands sent via OSWord &7F
> into the corresponding operation for the 177X.
 
Z-Break doesn't change the operation of the DFS in any way. All
OSWORD &7F commands are translated to the commands the 1770
understands. That's the whole point of an API.
 
The only thing that Z-Break does is intercept OSBYTE 0 and 129
and them identify the machine as a BBC B instead of a BBC B+.
 
-- 
J.G.Harston - jgh@...                - mdfs.net/User/JGH
Opposition is about asking questions, and Government is about not answering
them.