It's a question of degree of emulation. A modern PC 'emulates' a PC. There
are no 'PC's left - a co-called PC nowadays is any machine that follows the
'standards' that define a PC. Even Intel processors (and clones/derivatives)
'emulate' the instruction set of the older Intel processors. A Pentium (and
smilar) are now really RISC (at heart) processors that nowadays emulate the
CISC instruction set of older Intel processors. On startup, even a modern
state-of-the-art PC emulates the now ancient 8/16 bit 8088/8086 based PC's -
until the BIOS/OS switches the processor into 32-bit protected mode.
The backwards emulation took its toll to such an extent that PC
manufacturers had to drop ISA and some other old PC standards - but a modern
PC still emulates a LOT of the old XT/AT standards - even if rarely used
nowadays. If the Apple emulator merely emulates 32/64 bit processors and
modern PC standards, then it is possible that a Mac emulating a modern PC
could outperform a modern PC (which still supports 16 bit modes etc.) It
wouldn't be the first time that a different architecture has emulated a PC
and out-performed it. The Acorn Archimedes outperformed 286s and some early
386s when emulating a PC. Even the home Amigas outperformed XTs and some
ATs when emulating PCs
- if the emulator has only to run PC software it's not taking time out
monitoring all the hardware in PCs (it will still have to monitor its own
h/w - but can do that in 'native' mode). I supoose it's posible that some
emulators may recompile the software (when installed) to native instructions
too (treating the PC binaries as a kind of source code). I suspect the Mac's
PC emulator will cope ok with modern s/w but legacy s/w may give it a
headache - legacy s/w can give XP a headache on machines we call PCs. Even
some older PCs had problems with compatability - Apricot Zens and some other
PCs had hiccups running DOS 4.0 for example. Some even older PC clones were
merely MS-DOS compatible - and tripped over when PC programs wrote directly
to the hardware. RML i386 PC clones were an example - they looked like PCs,
had the same buses as PCs and ran DOS and Windows - but some PC software
would crash them and BBC emulators written for them wouldn't run on any
other make of PC. Some of the emulation could maybe be done by support chips
in the Mac. For example, some 16-bit games consoles had Z80A chips in them
(to help with things like sound and I/O) - and these could be utilised by
emulator writers to help emulate older 8 bit computers and consoles. So it
is possible that Macs may have some PC function compatible chips, on the
graphic cards say, that could be used to good effect. I remember a h/w Atari
ST emulator card for early PC's - the card had much of the ST's hardware on
board - and used the Intel processsor to shift output to the PC.
Unfortunately, said card was too processor specific - it only worked with
genuine Intel processors - it locked up AMD and other clones. But on Intel
powered 286s it emulated STs perfectly and was faster than 'real' STs - and
was able to use the PC's hard disk etc. Some musicians I knew had one (in
those days, STs were musicians favourite computers).
Allan
PS No trees were harmed in the sending of this message and a very large
number of electrons were asked their permission to be terribly
inconvenienced. (And threw a party for them afterwards for being really cool
about it).
Disrupting the unnatural balance that you, as a conscious human being and a
confused mass of energy, have created.
-Disturb the mind -
>From: Chuck Norcutt <chucknorcutt@xxxxxxxxxxxxxxxx>
>Reply-To: olympus@xxxxxxxxxx
>To: olympus@xxxxxxxxxx
>Subject: [OM] Re: iMac for Workflow
>Date: Sun, 19 Nov 2006 17:06:17 -0500
>
>I'd believe that if Macs had access to different processors than PC's
>do. But a Mac running Windoze has to run the same software running on
>the same processor and, in addition to the PC's workload, it has to pass
>through the Parallels translation layer at least part of the time.
>
>I suppose it's possible that Apple does their own motherboard support
>chips which might convey a performance advantage but I don't consider
>that likely given their historic cost/volume problems. Sounds like more
>Mac folk lore to me. But I'd consider it a resounding success if there
>was no more than 10% overhead and that is probably quite doable and
>pretty much unnoticeable.
>
>Chuck Norcutt
>
>Chris Barker wrote:
>
>
> > You can run Windoze on the Intel Macs (aaargh! ;-)) with a system
> > called Parallels, about USD60. Apparently it is faster than a PC
> > running the OS.
>
>
>
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