Mac transition to Intel processors
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At the 2005 Worldwide Developers Conference (WWDC), Apple Computer CEO Steve Jobs made the historic announcement that the microprocessors powering his company's Macintosh computer range would transition from PowerPC parts supplied by Motorola and IBM, to those of hitherto rival company Intel.
History
Jobs began by examining the previous transitions successfully completed during the Macintosh's lifetime. The first, itself a processor transition, migrated the platform from the 68K series of chips from Motorola to their new generation of PowerPC parts developed jointly with Apple and IBM.
More recently Apple has transitioned the operating system for their computers from OS 9 to a modern Unix-like operating system known as Mac OS X. OS X was derived from NeXTSTEP which was bought by Apple for the purpose. OS X now includes features such as pre-emptive multitasking, lacking in previous versions of the OS, as well as a graphical user interface that devotees of the platform believe represents the real "heart" of the Mac. For these users, the nature of the processor powering the system is of less consequence than having an OS that for them improves the speed with which they can accomplish tasks.
A long-rumoured internal project within Apple, known as "Marklar" was designed to ensure that builds of Mac OS X were sufficiently cross-platform as to compile for both PowerPC and x86-class processors. Jobs confirmed at the conference that every version of OS X had been thus compiled, continuing the cross-platform tradition of NeXTSTEP. It is not known what other processors, if any, Apple maintains current builds for.
Reasons for the Transition
Two years earlier, Jobs had introduced the PowerPC G5 processor and promised that within a year the clock speed of the part would be up to 3 GHz. In the meantime Motorola had spun off the PowerPC production into another company, Freescale, and this company had a dual-core G4-class chip in the pipeline.
Unfortunately the 3 GHz G5 was not achieved even two years later and rumours continue that IBM's low yields on the POWER4-derived chip were to blame. Further, IBM had been unable to lessen the heat produced by the chip sufficiently to enable it to be deployed in a laptop computer, now the fastest growing segment of the personal computer industry.
Overall, the public impression is of a Freescale somewhat more interested in embedded applications, and an IBM increasingly distracted by games consoles. Whilst the latter are obtaining PowerPC cores at 3 GHz, they will remain unchanged for many years after deployment. In contrast Apple needs a steady stream of incremental improvements without having the sales volumes to drive manufacturers to achieve them.
Meanwhile the x86 instruction set architecture has achieved massive market penetration, in particular at the desktop scale. Intel itself is the world's largest chip vendor and has significant brand awareness among the consumers Apple would like to target. Intel is able to provide Apple with a complete system rather than just a processor and can do this in a volume unlikely ever to be tested.
Apple has relied on two companies for its microprocessor chips and in neither case was there anywhere else to turn when they could not apparently deliver. This psychology may be reflected in Apple's choice of Intel. Although the latter is still a single company it is the largest in the sector and one whose desktop ambitions are unlikely to be undermined by other market considerations. Moreover, should Intel fail to deliver, a move to an alternate supplier (such as AMD) would be an easier objective then either the 68K-PowerPC transition, or the PowerPC-Intel one.
Benefits of the Move
The first and most tangible benefit of the transition will be any performance improvement in Apple hardware. Whilst Apple equipment is not slow at the present time, Jobs implied in his presentation that the performance of PowerPC was likely to tail off going forward, and in particular that the performance per watt (that is, the speed per unit of heat generated) would not be able to match that in the roadmap provided by Intel. With laptop sales being such a important segment of the market, the ability for Apple to rapidly develop lightweight, highly-performant devices with long battery life cannot be overstated.
Advocates of the transition also point out software benefits. Technical users will appreciate the ability of Apple systems to run all four classes of software at near native speeds; OS X binaries, Java applications, GNU/x86 applications and potentially now Win32/.NET/x86 applications. No other hardware vendor can offer more than three of these. Virtual PC, a Windows emulation solution for Apple PowerPC sold by Microsoft, could now enjoy much more success with performance improved through virtualisation rather than emulation. For those customers wishing to achieve a more conventional environment, a dual, triple, or even quadruple boot solution (with OpenSolaris say), would be possible on an x86 Apple device. Apple have already indicated they do not intend to take steps to prevent other operating systems being deployed on their new machines.
Although most games are constrained through the use of DirectX API's not available for the Apple architecture (on either processor type), reductions in the time required to port these from Windows nevertheless might be observed if developers are able to ignore endian issues associated with moving from x86 to PowerPC.
Hurdles Associated with the Move
Not all the outcomes are positive however, and the Macintosh community has voiced its fear and uncertainty since the announcement was made.
Psychological
Apple has benefited greatly among its user community from the psychology of "thinking different." Many Apple users for example, have enjoyed the ready availability of a consumer desktop that was completely separated from the "Wintel" alliance. Those often very technically-inclined users, now feel betrayed by an Apple that has apparently sold its soul. Users express what to PC advocates seem relatively insignificant fears, e.g. that Apple will include the "Intel Inside" logo on the computer, but this is really the surface view of a deeper foreboding that the Intel supertanker will simply crush the minnow Apple. That the latter might become a "me too" vendor of PCs, particularly if Apple is buying the complete system from Intel and not simply the main CPU, has echos of the gradual decline of other companies previously involved with Intel. These arguably include Silicon Graphics, BeOS, as well as NextSTEP itself. A source of chips from AMD would have retained the performance crown and allowed the naysayers to remain on-board.
This suggests that the purchasing demographic of the company's machinery might change from that of technical users now turning to Linux or a BSD which they can use on any preferred configuration, while consumers increasingly disillusioned with Windows' repeated security scares rotate towards Apple as the most obvious desktop alternative. It is likely that the latter demographic represents a much larger market than the former.
Finally there is the supposed cleaner architecture of the PowerPC. Advocates of this architecture suggest that x86 has succeeded in the marketplace by sheer strength of research and development cash, rather than because it is an inherently better design. Moreover, they suggest that a large amount of historical baggage is carried around by x86 for backwards compatibility reasons that isn't needed by Apple. Others counter that whilst the demonstration machine was a Pentium 4, at no point did Jobs say that x86 would be the final deployed chip. Also, arguments about the cleanliness of RISC vs CISC is moot these days, since even CISC designs are RISC at the core. Nevertheless PowerPC advocates are having to eat a certain amount of humble pie at the precise moment at which PowerPC seemed to be in the ascendent with even Microsoft choosing it for XBox 2. It may be that since Microsoft was so ambitious in cultivating alternative chip suppliers in AMD and IBM, that Intel made Apple an impossible-to-refuse offer so as to cultivate an alternative operating system supplier...
Hardware oriented
The most obvious problem Apple has to deal with in the short term, even assuming that they are able to carry users with them to the new processor, is the so-called "Osbourne effect." This is named after Adam Osbourne who was so successful at marketing his upcoming new devices that customers stopped buying the current offerings in anticipation of their arrival. The company went bankrupt before they could be completed and shipped.
Clearly Apple needed to involve developers at an early stage so that software would be available for the new machines when they begin retail. But the reason the announcement has been relatively low-key is so as not to alienate users who might otherwise have bought a PowerPC Macintosh but will now delay purchasing until the new Intel variants have become available. Apple has more cash available than did the Osbourne company, but no company will wish to sit on stockpiles of unsold products for long.
There are questions over the extent to which Apple will retain control over the non-processor components of the system design. The interior of a current Apple G5 is as much a work of art as the exterior. Apple is traditionally a systems builder and if it is simply purchasing whole, or nearly whole, motherboards and chipsets from Intel then it is not apparent how much industrial design differentiation can be expected. On the other hand, Apple is a very agile vendor with little historical baggage to carry. Intel may treat Apple rather as Ford does Aston Martin - a way to test the latest and greatest technology in a premium product hand-crafted for maximum effect before some months later the technology filters down to cheaper systems. At the very least, purchasing most components from Intel ought to guarantee cost savings at the wholesale level.
Apple has indicated that the new Intel PCs will not use their traditional Open Firmware. Some users swear by certain features in this technology (particularly "Firewire Target Disk Mode") and the loss would be keenly felt. A new Intel technology for firmware, Extensible Firmware Interface (EFI), promises more functionality and removes the traditional PC reliance on the BIOS, seen as non-standard and dated.
Intel itself is seen among the Macintosh community as being a purveyor of hot-running chips. Indeed, this unfortunate feature of the Pentium range was the subject of a mickey-taking "Burning Bunnies" advertisement by Apple. If Intel can indeed produce cooler chips (and the widely acclaimed Pentium-M series demonstrates that should be possible) then only the lingering marketing message need be overcome. However versus the current G5, floating point performance is seen as limited and the number of registers available to applications is rather fewer than in a PowerPC alternative. Moreover it is not clear whether the next generation of Intel chips will be able to match AltiVec functionality and is 32-bit only, at a point when Apple has made 64-bit a cornerstone of its marketing.
Finally it has been rumoured that Apple was backed into this position by content producers eager for Apple to take advantage of Intel's otherwise roundly condemned on-chip digital rights management (DRM). This seems unlikely since Apple would not be able to take advantage of it on PowerPC boxes and users would simply continue using their current equipment for tasks requiring DRM. Nevertheless there is every chance that this technology will be used to prevent OS X from working on non-Apple "white box" PCs, a position Apple is determined to maintain despite this limiting the potential take-up of the OS.
For Apple to allow otherwise would cannibalise the hardware sales which still form a very large percentage of their revenue. Whilst Apple devotees anticipate that a "win" for the cracking community of such scale as OS X on an unsupported but highly-desirable top-end Opteron for example, means that it will be inevitably tried, they see the demographic of people willing to accept the consequences of this (such as not being able to use Software Update for example) as being relatively small. This is an unproved hypothesis, however.
Finally the use of x86 means that software performance will be much more transparent than when features of the PowerPC enabled benchmarkers to hide behind the "MHz myth." This was a claim that clock speed hid the true story of a computer's performance as it didn't take account of differences between architectures. While ostensibly true, it allowed machines deficient in specification to be sold long after upgrades were due. Now, identical applications placed side-by-side on OS X and a competing operating system will be comparable based purely on the speed of the software.
Existing applications
Ironically, because of the NeXTStep cross-platform heritage it is likely that application-related disruption will be minimal. The evolution depends somewhat on the as-yet unresolved question of whether the transition is to Intel, or to a dual-platform strategy that includes Intel.
Firstly, Java applications that don't rely on JNI, Dashboard Widgets, and scripts that execute inside an interpreter all work immediately on both processors and are immune from changes. OS X applications that can't be migrated run inside a PowerPC dynamic translator on Intel called "Rosetta." This has limitations, most particularly in that it can't run AltiVec code, but most applications that use AltiVec fall back to a G3 instruction set when AltiVec is not found and will still run in that configuration under Rosetta. Rosetta itself is broadly a better solution than Classic was for OS 9, as it doesn't require a whole OS to be loaded as a sub-system before the application can work and translations are cached for maximum performance on the second and thereafter executions.
AltiVec itself has been encapsulated since OS 10.3 by a vectorisation library that should enable vector-aware applications to be ported readily. It is understood that Intel's SSE3 is being extended to make it "better for games" but this may in fact include certain AltiVec-related changes as well.
A simple recompilation step that generates a Universal (previously called "Fat") Binary is expected for Cocoa applications. Carbon applications may require some additional tuning but not of the complexity of the transition from OS 9. It is worth noting that this is only likely to happen when the target wasn't specifically x86. For example, games ported from x86 or Virtual PC applications are unlikely to get significant PowerPC optimisations if the strategy being pursued is an eventual migration entirely away from the minority architecture.
Future
It seems as of this writing that the transition is fully away from PowerPC although internal builds of these may proceed as have Intel builds for the last five years. Apple has shown that it likes to have processor options and will act on them if the business case seems appropriate. Within the same department, builds should also include those for AMD, as well as SPARC and even Cell.
AMD was the obvious and in many opinions preferable choice for Apple. There are good reasons for even the most ardent detractor to grudgingly admit the benefits of x86 but those same ardent individuals are unlikely to accept Intel at all. AMD has the performance crown and with new production facilities can meet Apple's volume requirements. Moreover since they do not supply the entire platform, there would be less anxiety among the Apple customer base about the loss of identity. AMD were selected by Sun Microsystems to power their recent workstation range and Sun's technical demographic is not dissimilar to Apple's.
However, Sun is not a laptop vendor and AMD does not appear to offer laptop specification chips of the same calibre as Intel. They are also still bound to IBM's apparently failing process technology. Apple may pursue a dual-supplier strategy with AMD in the future to enable those Wintel detractors to once again adopt the platform.
Cell does sport a general-purpose PowerPC core as well as the multiple SIMD cores and while is not intended as a workstation chip has been recently demonstrated powering a Linux environment. This required significant effort to establish however. Finally Itanium has not been a market success and would arguably not improve the Xserve line's penetration if adopted.
Not counting Itanium, the roadmap for Intel in the immediate future suggested by Ars Technica includes "Yonah" (a dual-core Pentium-M successor with a 65nm process), "Sossaman" (a desktop version of Yonah) and "Conroe" (another desktop Pentium-M successor, and 64-bit). None of these processors have been confirmed for Apple at this stage. It is likely that laptop and lower-end machines will be revised first as they are most in need of refresh in comparison to the market as a whole. High-end machines will be revised last as the current G5 is still very competitive and an Intel alternative would not appear to add a great deal of performance.
Less realistically, it is possible that Apple is using this hardware change in order to rekindle previous opportunities to license the operating system. Other than Apple no major vendor sold a desktop PowerPC based system. Now it is possible that Apple will select certain hardware suppliers to increase the roll-out of OS X without simply unbundling the operating system and rekindling the "clone wars." As an existing hardware partner for the iPod, Hewlett Packard seems a plausible choice.
Alternatively Apple could license Sun Microsystems to bring the OS to AMD processors. Apple already has a deep relationship with Sun through Java. Apple has licensed this and related technologies for some time and Sun have incorporated certain desktop Java recommendations from Apple into the source base. Most recently Jonathan Schwartz of Sun has even dared suggest OpenSolaris as an alternative kernel for Mac OS X instead of XNU, a move that for many long-time operating system watchers, would bring together the best of all worlds.