There's been an amazing amount of press over the past
year-and-a-half about Apple's transition from the PowerPC platform
to Intel.
Apple claimed that IBM wasn't able to provide faster processors
for the Power Macs or a G5 for laptops. IBM has disputed this.
However, since the fastest Power Mac
G5 (2.5 GHz) is water cooled and the new Mac Pros (at up to 3.0 GHz) aren't, there
may be something to that.
Whatever the real reason for the switch, as of August 2006 Apple
had completely transitioned to Intel processors.
There are many still using Macs with G3, G4, or G5 processors
(as well as older processors), and Apple will probably continue to
offer support for at least the G4 and G5 in the next few versions
of OS X. If they don't drop G3 support in the forthcoming
OS X 10.5 "Leopard" (which it seems like they will), they will
more than likely drop support in the following version.
Sales of OS X are profitable, so as long as PowerPC users are
willing to purchase it in any kind of volume, Apple should continue
to release versions of OS X for PowerPC Macs.
CPU Transitions
Apple is probably the only mainstream consumer computer company
that has managed to change processors and operating systems several
times. They transitioned from the 6502 in the Apple II to the
Motorola 68000 processor when the
Macintosh was introduced in 1984. [The 6502 had also been used
in the Apple III, and the 1983
Lisa also used the Motorola 68000,
but that is incidental to this article. ed]
Apple also transitioned from Apple DOS to the classic Mac OS and
then to Mac OS X.
Since the Mac was incompatible with the Apple II, it required
all new software, there was a big transition from the Apple series
to the Macintosh. (Apple II models were still available until 1993,
so not only was it a transition, but Apple managed to sell two
different and incompatible types of machines at the same time.)
Ten years later, Apple started transitioning from the Motorola
680x0 family of CPUs to the PowerPC with introduction of the
Power Mac 6100, 7100, and 8100
in March 1994.
After a 12 year run with PowerPC, the Mac transitioned to the
Intel Core family of CPUs over an eight month period in 2006.
Emulation
When the PowerPC transition took place, Apple developed an
emulator that could run 680x0 code on PowerPC processors. This
allowed Apple to slowly port the Mac OS to the new CPU family and
let users run software written for 680x0 Macs.
When Apple and NeXT came together in the 1996/97, NeXTstep was
primarily available on the Intel x86 and 680x0 platforms, with
ports available for other architectures. NeXT has been working on a
PowerPC port of NeXTstep, and Apple had to finish rewriting
NeXTstep to run on the PowerPC chips they were using.
Unknown to most, Apple also continued developing an x86 version
of Mac OS X. This allowed them to have OS X ready to go
for Intel's new Core processors - and the Core and Core 2 processors
are a huge improvement over the older Pentium 4 chips and much more
cost effective than the Itanium (John C. Dvorak speculated
that Apple would move to the Itanium in March 2003).
With the new Intel Macs, we have is Rosetta, which allows
PowerPC programs to run without modification on the new Macs - but
with a speed hit, higher memory demand, and no Classic support.
Windows on the Mac
While it was entirely possible to run Windows on a Power Mac
using VirtualPC, it wasn't very effective. Emulation software is
generally slow, and since you can only make certain resources
available to the emulator, software can't take full advantage of a
system.
For those Mac users who needed to use Windows programs, such
using Microsoft Access or testing Web pages in Internet Explorer 6
(which wouldn't be necessary if IE were standards compliant like
Firefox and Safari), this created a frustrating experience - or it
necessitated the purchase of a Windows PC. Either way, you needed
to pay for a license for Windows, which for some is like supporting
the enemy in the mind of many Mac users.
This has changed with the Intel Macs. Now pretty much anyone can
install and run Windows on their new Mac, though many would wonder
why. (However, if you are into gaming, a Windows PC has many more
options available.)
What many don't know is that Windows was actually available for
the PowerPC, the DEC Alpha, and the MIPS processors in the early
90s. However, Microsoft saw little point in continuing any real
PowerPC support, since very few companies other than Apple made use
of the PowerPC in desktop computers. IBM released some PPC based
machines, but they focused more on their POWER systems for
mainframes and minicomputers and the RS/6000 workstations.
Further, since Apple has such tight control over their hardware,
it would have been extremely difficult to run Windows on Power
Macs.
Today there's a version of Windows Server that runs on the
Itanium platform. However, Windows is very tightly tied to the x86
platform, and it's unlikely that Microsoft would offer a version
for any other hardware platform unless there was a high volume to
support it. Windows just wasn't an option for the Power Mac, since
Apple keeps such tight control over their systems and wouldn't
offer Windows as an option on a Mac.
Market Share
Apple has very rarely commanded over 5% market share over it's
30 year history. That is changing with the Intel-based Macs. One of
the reasons is the ability to actually run Windows on them without
emulation.
It's hard to judge how many Mac owners will actually install
Windows on their machines (or use it to any extent), and installing
Windows on a Mac gives Microsoft increased market share as well as
money, which probably isn't the best idea.
Apple has hedged it's bets. Think about it. They moved away from
the PowerPC because they claimed that IBM was unable to get them
the chips they wanted. No one can really knock them for choosing
the Core chips. The new Core2s are the most powerful processors
available.
However, we know that Intel's track record isn't the
greatest:
- Intel has been slow to market with newer chips. Competition
from AMD has forced them to come out with newer chips and lower
their prices.
- Bugs in the Pentium processors: FDIV and F00F Bugs.
- Recall of the 1.13 GHz Pentium III due to instability
problems.
- Inferior NetBurst Architecture compared to the AMD Athlon64 and
IBM PowerPC G5.
- Excessive heat output of the Pentium 4 (similar to Apple's
problem with the G5).
- Itanium, a supposedly superior chip architecture compared to
x86 that still has very little market share.
Chip Architecture
The Core architecture is based in great part on the older
Pentium III chips. After five years of pushing the NetBurst failure on us,
Intel went back to the older design and improved it. Of course, the
biggest reason that the Core 2 is faster than the Athlon64 in a lot
of benchmarks is because it has a single issue SSE (Streaming SIMD
Extensions - similar to AltiVec in PowerPC) engine. This lets the
Core chips process multimedia type stuff very fast.
The Athlon64 takes two cycles to run an SSE instruction. I'm
willing to bet that when AMD releases their K8L update to the
Athlon64 with true Quad core support later this year (Intel's Core 2
Quads are actually two dual-core chips crammed into a single
package), we'll see Intel's lead dwindle.
If AMD can release a chip that is much better than the Core 2
chips (though it doesn't look likely at this point), you might be
able to get a future Mac Pro with AMD inside. There's no reason
that OS X won't run on an AMD chip, and some have managed to
hack OS X to do just that (not something I can condone, since
it's a breach of Apple's license - even if it is silly).
Let's say IBM (or someone else) releases an even better PowerPC
processor in the next few years, one that makes Intel's chips look
weak. Since Apple is still releasing OS X as Universal Binary,
it wouldn't take very much to come out with a new Power Mac.
Think about it: Most of the parts of a computer, Mac or PC, are
standard - PCI, PCI Express, AGP, USB, IDE, SATA, DDR, DDR2, SDRAM,
etc. All of these are or were de facto industry standards
regardless of the processor. When the Mac
II was introduced, it didn't take ISA cards. The Power Macs
originally came with NuBus and Processor Direct Slots before Apple
moved to PCI.
Other than the processor, the only other processor dependent
chip on a motherboard is the Northbridge
memory controller. AMD proved that they could still compete with
Intel even though AMD was no longer able to put its processors on
Intel motherboards.
AMD's chips have an integrated memory controller, which further
simplifies the design of the Northbridge (but makes changing memory
types more difficult like from DDR to DDR2) and HyperTransport
instead of a conventional front side bus like Intel's.
It would probably benefit Apple immensely to have the ability to
use different processors. Since OS X is based on Unix, and
Unix can run on almost any architecture (The NetBSD version of Unix has even been
ported to a toaster!), it would allow Apple to adopt the best
technology as it becomes available. The only disadvantage is that
Universal Binary software takes up more hard drive space, but
fortunately that don't effect performance.
Transitions
From Motorola 680x0 to Motorola/Freescale and IBM PowerPC to
Intel Core. From the original Apple computer to the Apple II and
III to the Macintosh to the Power Mac and now to the Intel Mac,
it's been an interesting 30 years for Apple.
What processor will your new Mac have ten years from now? Intel,
AMD, POWER, SPARC, or maybe something completely new?
We'll have to wait and see. And we hope Low End Mac will still
be here to tell you about it. 
