Re: [MiNT] Mac emulator

[tlang (Torsten Lang)]

Hi there,
> 
> > JK>Speaking of projects like this, by the way:
> > JK>
> > JK>   Anyone interested in a Mac emulator?
> > 
> > yes
> 
just a few remarks:
I personally like the idea of having a MacOS run on my Atari. I'm using
ShapeShifter on my 060 Amiga and can tell you that especially older versions
were quite stable. But there are a few cons:

1. The MacOS MUST have all its vectors at VBA=0, so ShapeShifter patches
the AmigaOS to move its vector table to a higher address (preferably Fast RAM).

2. The MacOS needs exclusive access to the video hardware. On an original
Amiga (or ST) this is no major problem since you can just open a second
screen (quite elegant on AmigaOS, for the ST we would need to fiddle around
with the BIOS). On gfx boards you run into trouble - so if an Amiga screen
is in front MacOS writes it over all around the screen...

3. MacOS is TERRIBLE slow since 7.1. But the older 6.x systems are not 32bit
clean. When you see an 040 Mac booting a newer OS with a lot of extensions
you'd think Windos NT is booting really fast...

4. Because of 3. you'll need at least a '040 (33-40MHz) to work. I think
there are not too many ST owners around with such machines...

5. Newer software and games are mostly for PowerPC based Macs. But there is
no ST compatible HW around with PPC (which doesn't matter since ShapeShifter
has no PPC support).

6. To use MacOS legally you need an old Mac to get the ROMs...

7. MacOS likes to have real SCSI and as far as I know at least a '020, so
the minimum requirement would be a TT (please note: Falcon SCSI has similar
limitations like the ST DMA concerning the transfer itself).

8. MacOS and its applications like lots of RAM. I you really want to WORK
with it (let's say Adobe Photoshop) I think 64-80MB would be OK (well, my Amiga
is equipped with 150MB so that AmigaOS and MacOS can work quite good in
parallel).

So before investing lots of time in porting an emulator for another dying
(or already dead) hw platform think about how many users really could use
it...

Please don't misunderstand me: As I said I like the idea of having a MacOS
running in parallel on a MiNT machine but from a realistic point of few
it may not make very much sense...

With best regards,
             Torsten Lang