Re: GS/OS for xgs emulator?

[spec@vax2.concordia.ca (Mitchell Spector)]

In article be404@yfn.ysu.edu (Adalbert Goertz) writes...

>>Dr^5 Tom (owsw@aol.com) wrote:
>>What I'm really waiting and hoping for now is a Mac SE emulator for the
>>IIGS.  : )
>> 
>>Cheers,
>>Tom
>
>Is that feasable?

    Feasible, yes. Practical or usable? Almost certainly no. First off,
the Apple IIgs has a maximum resolution of 640x200, whereas the Mac SE 
had a screen resolution of 512x342 (that's 142 pixels more vertically).
This leaves you with two choices using GS hardware: cut off the lower
part of the screen your emulating, or allow the user to scroll around;
though either way is not a good idea. The best solution would require
either a Video Overlay Card (it supports an interlaced mode that doubles 
the vertical resolution) or a Second Sight card. Keep in mind though
that a relatively small number of people own either card and little
software support has been done for either.

    The next problem is speed, you would need the 65C816 to emulate a
68000 processor running at 7.8 MHz. The fact of the matter is the GS's
processor is much too slow, even with the fastest accelerator added.
You would also have to emulate/translate Toolbox calls, sound, input,
output and other things as well, this would bog down emulation even 
more. The only practical way would be hardware emulation, along the
lines of the PC-Transporter (the Duet card was a shot at it, but it
was cancelled). The chances of anyone releasing such a card now has 
about as much chance as Apple Computer releasing a new Apple IIgs -- 
none at all.

    There was rumour someone was working on a Nintendo Gameboy emulator 
for the Apple IIgs, but I've not heard anything in months and gave up
hope on that (that too would probably be quite slow mind you). In the 
meantime, I'll just use "Executor" for my PC, which emulates a Macintosh 
faster than any real 68k and even some PowerMac's IMO. :) 

Mitchell Spector
spec@vax2.concordia.ca