Date   : Fri, 13 Mar 1998 18:54:17 +0000 (GMT)
From   : Tom Seddon <T.W.Seddon@...>
Subject: Re: [BeebEmul8] Master OS

On Fri, 13 Mar 1998, Mark Usher wrote:

> Can anyone tell me to which memory address the Master OS is mapped ?
> ie the BBC is &C000 to &FFFF (or &8000 to &BFFF depending on Jumper 21)

Most of the Master's OS is mapped to &c000 -> &FFFF as per the original
Beeb. (6502 reset vector is at (&FFFC) so the top area of memory has to be
ROM.) Some of the OS exists inside the Terminal ROM, which is why such a
basic utility takes up a whole ROM slot. I seem to remember reading
somewhere that there is relevant code inside most of the built-in ROMs, as
some of the bundled ROMs had some free space in them and there was an
awful lot of stuff to fit in. If you're trying to take a copy, your best
bet is to save all of the built-in ROMs as many of them are
interdependent; I don't think the OS will work without the Terminal ROM,
and BASIC is integrated to some extent with the *EDIT command (and
vice-versa). 

Usual disclaimers for off-the-top-of-my-head-and-it's-been-6-years-since-
I-even-last-*saw*-a-Master type stuff apply :-)

--Tom