Apple has confirmed a Register report that Panther, aka Mac OS X 10.3, will not be a fully 64-bit operating system.
Greg Joswiak, Apple's vice president of hardware product marketing, this week admitted that Panther will be a 32-bit operating system tweaked to support 64-bit addressing.
That's the same technique implemented in Mac OS X 10.2.7, the version of the Apple operating system that will ship with the first 64-bit Power Mac G5s. Mac OS X 10.2.7, codenamed 'Smeagol', is a 32-bit OS, but certain libraries and other elements have been recoded to allow it to make use of the 64-bit addressing provided by the G5's 64-bit IBM PowerPC 970 processor.
In the run up to the launch of the G5 and subsequently, many Mac users assumed that Panther would be a fully compiled, 'true' 64-bit OS.
However, reporting on an chat with Greg Joswiak, Apple's vice president of hardware product marketing,PC World.com this week noted: "Apple hasn't announced plans for a pure 64-bit operating system; Panther, an updated 32-bit OS due out the end of this year, will have [Mac OS X 10.2]-like 64-bit support."
Joswiak himself says: "The important thing for us [is] we didn't want to create a separate OS that is 64 bits. What is essential is that this OS and this hardware will run 32-bit applications with no recompiling - it will just run them."
The interview confirms comments from sources close to the development of the Power Mac G5, which we reported exclusively earlier this month, that Panther will not be a fully 64-bit OS.
The 970 makes use of an optional part of the PowerPC specification which allows "allows 64-bit implementations to retain certain aspects of the 32-bit architecture that otherwise are not supported, and in some cases not permitted, by the 64-bit architecture", according to IBM PowerPC documentation.
The PowerPC architecture was always defined as a true 64-bit environment with 32-bit operation defined as a sub-set of that environment and a 32/64-bit 'bridge', as used by the 970, to "facilitate the migration of operating systems from 32-bit processor designs to 64-bit processors".
The 'bridge' technology essentially allows the 970 to host 32-bit operating systems and apps that have been modified to support 64-bit addresses and larger files sizes as both Smeagol and Panther have. Adding 64-bit address support to existing applications lies at the heart of the optimisations for the Power Mac G5 that Apple suggests developers make.
As we've written before, this approach allows Apple and its developers to start leveraging its new 64-bit processor as soon as possible, without having to recompile operating system and applications. The 970's 'bridge' technology also ensures that developers who aren't interested in 64-bit addressing can continue to target G4-class processors and systems and know that their code will still run on the G5.
It's a smart move that allows the platform to take advantage of the key aspects of 64-bit computing without forcing a migration from the 32-bit world. It also gives developers breathing room to get their applications 64-bit clean in time for when Apple decides that it does want to go fully 64-bit, presumably when all new Macs are based on 64-bit CPUs and there's a large enough user base of legacy 64-bit systems.
Most buyers of AMD's upcoming Athlon 64, by contrast, will have to wait until Microsoft ships a fully 64-bit version of Windows XP before they can take advantage of 64-bit computing. There is no Panther-like hybrid option available - 32-bit code that can cope with 64-bit addressing.
Initially, Windows users will be stuck with the 32-bit version of the OS, which the Athlon 64 also supports but which doesn't deliver any of the new chip's 64-bit benefits. More technically adept Athlon 64 users will presumably be able to run 64-bit Linux in the run up to the Microsoft release. However, many developers are waiting for 64-bit Windows XP to arrive before shipping 64-bit apps of their own - that isn't expected until early 2004, according to internal AMD roadmaps. ®