Re: Accelerator / VGA Graphics card

[Lockar <lockar@nospam.com>]

   It does sound like you are building a new computer here.  Why not
just do a PCI card that could work in a PC or Mac. Perhaps work in
both.  Like the //e card for the mac.  Now I know the ROMS might be
problam, but most people that would be interested in buying such a card
would actually have a couple of //gs's around.  So just pull the ROMs
off them.  Although I do see the problem of would the card use ROM 01
or ROM 03 or both.

    Now, I konw this stuff is way over my head, but that's what I am
thinking after I read all these messages about a card for the Apple II.

   -Lockar


In article <vpn9ar6h9ga818@corp.supernews.com>, brad <mrbrad@ll.net>
wrote:

> just lurking here... but if the "Woz" is watching..do we have a nice little
> hardware project to propose for you!!!!!!!!
> 
> i mean everyone else is into retro computing....why not you as well
> 
> my 2c worth
> 
> back to discussion at hand
> 
> brad
> 
> 
> 
> 
> 
> "Sheldon Simms" <sheldonsimms@yahoo.com> wrote in message
> pan.2003.10.25.18.55.39.204261@yahoo.com">news:pan.2003.10.25.18.55.39.204261@yahoo.com...
> > On Sat, 25 Oct 2003 06:51:35 +0000, Michael J. Mahon wrote:
> >
> > > Sheldon Simms replied:
> > >
> > >>On Fri, 24 Oct 2003 21:56:34 +0000, Michael J. Mahon wrote:
> > >>
> > >>> Sheldon Simms wrote:
> > >>>
> > >>>>On Fri, 24 Oct 2003 14:59:39 -0400, Charlie wrote:
> > >>>
> > >>> <snip>
> > >>>
> > >>>>> That makes sense and I like the idea of the 1MHz clock generating an
> > >>>>> interrupt on the card.  Wouldn't this free up the emulator to do
> other
> > >>>>> things (graphics) in between interrupts?
> > >>>>
> > >>>>Well yes, but it would probably do everything it needs to do and then
> > >>>>still be waiting around.
> > >>>
> > >>> Have you checked out how long the Pentium M requires to take an
> > >>> interrupt and restore state and return?  I'll bet that caches are much
> > >>> less helpful for this than you imagine, and _lots_ of cycles are
> needed.
> > >>
> > >>After reading this I poked around a bit in Intel documentation but
> > >>they are not very forthcoming. However, considering the front side
> > >>bus frequency of 400Mhz, and the fact that all code on the Pentium M
> > >>would be running in supervisor mode (i.e. - no need to change protection
> > >>level), I have a hard time believing that it couldn't handle a 1Mhz
> > >>interrupt source. But perhaps I'm wrong. In that case other measures
> > >>would be required.
> > >
> > > Note that FSB speed only applies to burst transfers from RAM to and
> > > from cache, and does not include the startup latency, which is probably
> > > 50-60ns.
> > >
> > > I'm not saying that the processor can't handle interrupts at a 1MHz
> > > rate, but I am saying that it may use a lot bigger fraction of the
> > > processor's time than a first reading of the specs might suggest.
> >
> > Well another option would be to have a bus-width bank of shift
> > registers (a shift-memory, if you will). The emulation code writes
> > the entire bus transaction out to this memory which is then clocked
> > out onto the bus by the 1Mhz clock.
> >
> > > If you're into computing for speed, Apple II's are a terribly
> > > inefficient way to get there.  ;-)
> > >
> > > And if you're into computing for fun, Apple II's will get you
> > > there at a very enjoyable speed.
> >
> > Well fun is the point of this card too. I'm not planning on replacing
> > my PC with an 80 Mhz IIgs...
> >
> > -Sheldon
> >
> >
> >
> 
>