Re: Accelerator / VGA Graphics card

[Sheldon Simms <sheldonsimms@yahoo.com>]

On Thu, 23 Oct 2003 17:14:36 -0400, Charlie wrote:

> "Sheldon Simms" <sheldonsimms@yahoo.com> wrote in message
> pan.2003.10.23.02.54.24.863017@yahoo.com">news:pan.2003.10.23.02.54.24.863017@yahoo.com...
> 
>> A Transmeta Efficieon can supposedly operate with only passive
>> cooling, which indicates even lower power requirements.
> 
> I looked at their website and the Efficeon does seem to be a better choice
> although they are vague about the actual power usage.  The most I could find is
> that it uses under 7 Watts.

I couldn't even find that. Do you have a URL for that?

> You would have to add a video chip though.  There
> is supposed to be a nVidia chip designed to work with it.

That mainly means that nVidia and Transmeta are doing common
marketing, but if there is going to be a reference design with
both chips, then it could well be a winner.

>> As for software, I know it can be done. In fact, I can do it.
>>
>> Perhaps I should simply write the software to run in supervisor
>> mode after being booted from a DOS floppy. That would solve that
>> problem. The question would then be whether anyone is interested
>> in helping get the hardware in place.
> 
> Yes, I believe that writing the software is the first thing you should
> do, assuming that some type of hardware is truly feasible.  I realize
> that this is sort of a "chicken or egg" thing.

It is somewhat. Ideally development work on both would proceed
at the same time, but the software may well take longer than the
hardware anyway, so it might be good to get started on that first.

But before I do that, I'd like there to be at least one person
provisionally committed to do some hardware work. Ideally that
would be someone who already has access to board design software.

> I wish I knew enough to
> help with the hardware because I think your basic idea is cool, but most
> of it is over my head.
> This of course doesn't stop me from asking stupid questions.  So here
> goes:
> 
> Would the processor on the card be running in place of the 6502/65816
> or would both be running?

It would replace the 6502/65816.

> Would all Apple II memory be maintained on both the card and the Apple?

The memory on the card would be the "real" memory. The main reason
for that is speed. There's no point in crippling the card's CPU by
requiring it to spend 90% of it's time waiting for the "old"
Apple II memory.

Apart from that reason, the 65816 emulation (perhaps I should call it
65816 code-morphing firmware :-) will require some memory, and once
you've got a SODIMM slot on the board, you might as well put at least
64Mb in it, so the memory will be there to use.

> How do you handle Apple software that relies on precise timing such as
> disk I/O?

The same way that traditional Apple II accelerators do - by slowing
down for a while after accessing timing-sensitive devices. How this
slowing down would be accomplished is yet to be determined. It may
be possible to do it completely in software, or it may require some
hardware assistance.