Re: Apple emulators that support "floating bus" video sensing?

[Dirk Thierbach <dthierbach@usenet.arcornews.de>]

Michael J. Mahon <mjmahon@aol.com> wrote:
> Perhaps, but I think that any program spending its time maintaining
> a "split" would not be doing anything that required acceleration
> in any case.  

Nothing "requires" acceleration. But it's nice to have, because you
can for example speed up a game during animations that are always the
same, and hence boring.

> And if it were doing something useful besides splitting
> the screen, it would likely be animation, which should be run at 1MHz
> to obtain the original intent.

The problem is not the original intent (if that would be the goal,
then the simples thing is to always run at 1MHz). The problem is user
experience, which is greatly enhanced if he can speed up things from
time to time, under his control. Speed up as in "everything suddenly
is faster, because it was too slow before". And that includes framerates.
At least that's how *I* use this feature of emulators :-)

> It would be a lot nicer to run the computation at full-bore, but
> have a simple way to slow down the screen updates and waits so that
> what is intended for a human to watch would run at constant speed.

In other words, you want to something that ordinary Apple II's couldn't
do, namely have a program that is aware if acceleration. That's fine,
but then you need not restrict yourself to what ordinary Apples could
do. Acceleration is an extra piece of hardware not found in an ordinary
Apple, so there's nothing wrong with assuming that you have extra 
"pseudo-hardware" in an emulator like a real-time clock.

> As I've said, I found a way to do this for all real Apple II's,
> with or without acceleration, but emulation seems not to be equivalent.

If there are no programs using it, and if the programs actually using
the vapour-lock would behave incorrectly, why should the emulator
be geared towrads "wrong" behavior? The emulator should work correctly
with respect to an ordinary Apple (without acceleration), and for
anything else, it should do what's most convenient. Breaking existing
programs just because those programs would break down in the same
way on an Apple with hardware acceleration is not particularly
convenient.

- Dirk