Date   : Fri, 02 Aug 2002 11:07:56 +0100
From   : "Dave Gilbert (Home)" <gilbertd@...>
Subject: Re: Executable programs on EPROM

Dawn and Austin wrote:
> Hi all,
> 
> I'm afraid I'm just going to have to display my ignorance here.
> 
> What can you 'write' to EPROM (I'm aware a suitable burner is required)?
> Are there any circumstances whereby a BASIC program can be written to EPROM
> and then run, the Equivalent of CHAINing them?

Yes it can.  The trick is to build an EPROM that is a ROM filesystem 
with a !Boot file that gets run (or is it chained....). There was a 
program in Acorn User many many moons ago to create an image from a set 
of files.

> Assuming this were possible, would it be possible to specify that the EPROM
> software be run automatically upon startup of the Beeb.  I know you can
> specify which 'slot' you want the computer to start up with, but for my
> above example the BASIC interpreter would have to be running for the ROM
> contents to be executed.

You can swap the meaning of break and shift-break using a keyboard link
in the dip switch area. (or on a Master with a config), such that power 
on or standard break, or ctrl-break autoboots.  If there is no DFS then 
it will autoboot off the ROM filesystem.

Dave