Re: Is this true?

[pausch@saaf.se (Paul Schlyter)]

In article <20021113193218.21158.00000705@mb-cu.aol.com>,
JWolf6589 <jwolf6589@aol.comnospam> wrote:
 
> I read this quote: "All PC-compatible computers (even a 1Ghz PIII) are
> equipped with hardware to provide this backward compatibility and are
> therefore able to execute the large no. of applications which have been
> developed for PC-compatible computers in the last 20 years."
> 
> If PC's are designed so smart, howcome the MacOS or should I say OSX is
> not designed to be 100% backward compatible with all software developed
> for any Apple computer ?  I mean all my Apple II software will not work
> on a OSX OS without a emulator,
 
OTOH PC's won't run CP/M-80 software either, without an emulator.  CP/M-80
was contemporary to the Apple II .....
 
> and some of my MacOS classic software will not run under OSX.
 
I think you'll find it impossible to run software for MS-Windows ver 1 or
2 on the latest Windows versions, not to mention software for GEM......
And Windows XP is not that popular among PC game enthusiasts, because
there are so many older PC games which won't run under Win-XP.....
 
> It is true OSX does offer a classic compatibility mode, but using this
> is KINDA like using a emulator.
 
True -- but Windows 95-98-MW-NT-2k-XP does the same thing when
running MS-DOS or Win-3.x programs: it provides an emulator.  That
emulator is built-in in later Windows versions so users rarely think
about it, but it is nevertheless an emulator: when an MS-DOS program
(running in a "DOS box) accesses a port address which it believes
belongs to a hardware device, an exception is generated which is
handled by Windows: then Windows may decide to abort the program or
to provide a software emulation of that hardware device.  If Windows
decides to emulate the hardware device, the MS-DOS program will have
no idea that the hardware wasn't real, but emulated.
 
> Maybe I am blind, but I know that when I use Windows XP I seem to
> have an easier time using older Windows 98/95
 
That's still 32-bit Windows software....
 
> software or even DOS software,
 
Windows runs DOS software within an emulated DOS environment.  True,
the CPU instructions themselves need not be emulated since the Pentium
can run (most of) the old 8086/88 machine codes, but the environment
need to be emulated.
 
> than if I were using Mac OSX and using ProDOS (Apple II software)
 
Attempting to do that would be equivalent to trying to run CP/M-80
software on a Windows machine: that too will require an emulator.
And the Pentium is unable to execute 8080/Z80 opcodes.....
 
> or Mac OS classic software.
 
That is equivalent to attempting to run Win-3.x and earlier software
on a modern Windows machine: that too is done within an emulated
environment.
 
> Also on the PC I am able to partition a hard drive to use any Windows
> or DOS OS,
 
...or, more interestingly, some flavor of UNIX .....
 
> but on the Mac this is simply not true.  Its a pain as I have a few
> usefull programs that will not work in a non OS 7.x environent.  
> Hence the Macs shipping in 2003 will not even be able to boot Mac
> OS 9.x!  
-- 
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