Date   : Sun, 28 Sep 2003 19:27:14 +0100 (BST)
From   : Pete Turnbull <pete@...>
Subject: Re: BBC Micro lazy delayed boot!

On Sep 28, 16:33, Andrew Hancock wrote:

> I think this applies to languages only, eg Basic, Pascal, Logo and
View etc
> Languages must be in a higher priority socket left most socket on a
BBC, and
> OS ROM in the left most socket followed by the language, usually
Basic.
>
> Service roms eg DFS can be in any socket.
> - -----Original Message-----
> From: Chris Thornley [mailto:C.J.Thornley@...]
>
> Isn't there an order you have to have roms in i.e pripority in there
> sockets so they are initalized in a certain order?

Not quite.  There are, for the purposes of priority, three types of
ROMs: language ROMs, filing systems, and other service ROMs.  (Aside:
apart from BASIC, all ROMs, including languages, are also service ROMS.
 But there are some ROMs that are only service ROMs, and don't contain
either a language or a filing system.)

The language ROM in the highest-numbered socket at startup (or reset)
will be othe oner that starts up (and prints its banner).  Similarly
the FS with the highest numbered socket will be the one that beconmes
the default filing system (and prints its baner).  The relative order
of the highest language and the highest FS does not matter, nor does
the order of either language or FS relative to any other service ROMs.

The only things you'll change by re-ordering the ROMs, are the order in
which they get to claim memory at startup (which will determine who
gets what private pages between E00 and whatever PAGE ends up at) and
the order in which they get to interpret "unknown" star commands.

The only thing which will care is a badly written ROM that tries to
grab hardware (eg if you have DNFS -- which knows about the TUBE -- and
also a Torch MCP ROM -- which *thinks* it knows about the TUBE but
doesn't actaully follow the correct Acorn protocol -- and in that case
it will matter which comes first, if you have a second processor
attached).

> I seem to rember but have to check that on certain motherboard
revisions
> jumpers had to be cut.
>
> Chris

Well, yes, for DFS or NFS, you have to remove the relevant NMI link to
enable the filing system to work.  That's true on all revisions.  S9 is
the NMI link for DFS.

-- 
Pete                                           Peter Turnbull
                                               Network Manager
                                               University of York