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

[sicklittlemonkey <Nick.Westgate@gmail.com>]

On Mar 18, 4:20 pm, "Michael J. Mahon" <mjma...@aol.com> wrote:
> I think AppleWin may work on the PC, but if it accelerates the "virtual
> video" as it accelerates the processor, then it may not.
>
> All the reasonable uses I can think of for video sensing and VBL sensing
> are related to an absolute time base, and should not be subject to
> acceleration (just as it is not in a real Apple II), but I'm not sure
> that emulator writers agree...

AppleWin, probably like most emulators, accelerates the CPU by running
the whole machine at a faster clock. That includes the bus and
therefore memory reads - which in the case of floating bus reads would
mean software-percieved accelerated video generation.

Even if video rendering is decoupled from the accelerated emulation,
the floating bus reads would be accelerated and not suitable for your
purposes.

> What I'd like to know is which emulators *do* keep the emulated video
> period at 1/60th second (or 1/50th for PAL ;-).

Again, Virtual ][ is the only other one that I know of.

Cheers,
Nick.