Re: Apple Drops Backward Compatibility for Next MacOS

[pubpc1@library.ucla.edu]

shack@frii.com (Randy Shackelford) wrote:
><pubpc1@library.ucla.edu> wrote:
>
>> Well, I might agree with you.  The "PowerMac" is as different from a
>>680x0 Mac as it is from a IIGS.  I would like to see Apple actually port
>>GS System Software (GS/OS and the Toolbox) to native PPC code, though.
>>This would be more flexible than a mere emulator and be just like how the
>>Power"Mac" runs 680x0 Mac software.
>
>Wrong again. When the first Powermacs came out, some Apple guys were
>saying that 68K emulation is easily done because only the processor is
>different, the basic architecture is the same as on an '040 Mac. This
>makes emulation a matter of translating the 68K code.

As far as hardware components is concerned, with the exception of the
Ensoniq and the slots and some features of the VGC, the IIGS is pretty
similar to the architecture of the Power"Mac" too!  It uses the same
serial communications chips, supports the same IWM/SWIM (before you say
something, the AppleDisk3.5" driver has built in support for the SWIM
on a Apple II 3.5" Disk Controller...aka. SuperDrive controller) and
the same ADB port.  The hardware is there.  Sure, you may need an AV
model to get Ensoniq like architecture and you would lose 3200 color
mode (no scan line interrupts), but otherwise you could easily implement
GS/OS and the GS Toolbox the same way the Power"Macs" implement MacOS
and the Mac Toolbox.  Initially through emulation, but slowly moving
parts of the code to native mode.  Without a separate emulator, you
would also lose 8-bit Apple II function.

This is, of course, if you decide to emulate no hardware except the
processor (which is what we are discussing).  Otherwise, you could put
in some code to intelligently intercept 3200 color mode function and
throw up a 12-bit graphics screen, doing the conversion on the fly.

>This was done in the first generation with an interpretive emulator,
>which was replaced with the dynamic recompilation emulator. Emulating
>a IIgs would mean emulating the processor and all the hardware too.

The only extra hardware would be the Ensoniq and some features of the
VGC.  Otherwise, the Apple IIGS functions a lot like a Macintosh.  GS/OS
and the Toolbox can be made to run on a PowerMac much as 680x0 Mac
software does.  Again, this is treating the IIGS as a separate 16-bit
computer from the 8-bit Apple IIs.  The Apple II itself is emulated
via the Mega II chip, the same one that is used in the IIe Card for the
Macintosh LC.

>I really can't figure out why anyone would want to run old
>underpowered IIgs native apps on a new Mac.

Because I want to preserve my software and data investment.  Apple never
provided an upgrade path to their loyal customers.  Did they provide a
trade in?  No.  Did they implement translators for GS data formats?  No.
What if I can't afford to plunk down hundreds of dollars for new software?
What if I'm happy with my current software and don't WANT to switch?
What if I need to access my data?

Besides, the usefulness of the native IIGS apps is relative.  If you
compare AppleWorks GS to ClarisWorks, then of course ClarisWorks would
have more features.  It had time to improve over several revisions.

If you compare AppleWorks GS to TeachText, however, AppleWorks GS would
be much more useful.  Because of its tight programming (a necessity on
the IIGS), when run on the same PPC it would run faster than even simple
Mac text editors but have the features of a decent integrated software.
You may be using ClarisWorks for purposses AppleWorks GS was intended,
but AppleWorks GS would take over from other programs.

>This is messed up, first we had that Philip Mcdonnough dude (who has
>since departed csa2) trying to convince people that a IIgs isn't an
>Apple II, now we got a guy saying a Powermac isn't a Mac.