Re: 6809 mill clone

[Michael Black <et472@ncf.ca>]

On Mon, 6 Aug 2012, Steven Hirsch wrote:

> On 08/05/2012 11:37 PM, Alex Freed wrote:
>
> > I'm
> > even thinking of designing a new 6809 board for Apple that would be similar 
> > in
> > concept to the PCPI Applicard just as the Mill is similar to the SoftCard. 
> > The
> > new card should run a 68B09 at 2 MHz, have a minimum of 128K of RAM on 
> > board,
> > an MMC card for mass storage and communicate with the Apple bus via a 
> > couple
> > of shared registers.
> >
> > Since this would be a unique design not compatible with any existing 
> > hardware
> > it only makes sense to start it if it is clear who will write the drivers.
> > Even before the final hardware implementation is done we can implement such 
> > a
> > system on the Carte Blanche.
>
> Boisy is most definitely the right person to ask about the intricacies of 
> OS-9/NitrOS-9 and 6809/6309 assembly programming.  He's forgotten more about 
> it than I'll ever hope to know.
>
> I'd love to see a minimum of 512k on such a card, and it goes without saying 
> that I want one :-).
The limitations in the old days were in part the cost of RAM, which no 
longer figures in.  The CoCo was probably the most popular computer to run 
OS-9, yet when the CoCo III was released, it allowed for relatively large 
chunks of RAM, 8K.  That's good for large programs, lousy for small ones, 
and it was simply because the hardware did it in 8K chunks.  Later, there 
was some modification, I never saw it, to allow more RAM, that was later 
when RAM was much cheaper.

So the best solution is to allow for more RAM, but also smaller chunks of 
segments.

  Michael