Mac OS X ARM port by Apple work experience kid revealed
Project sparks non-Intel-powered MacBook rumour fever
A Dutch computer science student's homework has stirred the old rumour that Apple may ditch the Intel platform and power its Macbooks with ARM processors.
Tristan Schaap's bachelor thesis at the Delft University of Technology described work he did at Apple as an intern: getting the core of Mac OS X to run on an MV88F6281 processor - an ARM926EJ-S-compatible component, made by Marvell [PDF], rather than silicon from Intel.
Written in 2010 after a three-month spell slaving away in the Platform Technologies Group in Cupertino, Schaap's dissertation was embargoed for a year and published in August 2011. The 16-page document was seized upon by AppleInsider.
The document, Porting Darwin to the MV88F6281: ARMing the Snow Leopard, describes his 12-week job getting Darwin - the lower half of the Mac OS X operating system - to work on a single-core 1.2GHz ARMv5-compatible processor. Bear in mind that ARMv5 is not the latest revision of ARM's architecture; the beefy dual-core CPUs in the iPhone 4S and iPad 2, for example, use much more recent spins of the processor tech.
The essay tracks Schaap's problems with ARM's Thumb instruction set and several kernel bugs. However, the boy did well enough to get a job: he now appears to be working as a Core OS engineer at Apple, according to LinkedIn.
Though the embargo on the paper gives it an air of secrecy, it can't be that much of a surprise that Apple is playing around with these projects and testing out their options. And the fact that they gave the task to the work experience kid doesn't suggest that an ARM-based MacBook Air is anything to expect immediately. Porting an OS to another chip system can be a good way to test for bugs if nothing else.
And then OS X already runs on ARM chips - in the form of the iOS operating system on iPhone and iPad. And in that arena there's plenty of space for Apple to innovate on the ARM platform. Apple supremo Tim Cook told analyst Richard Gardner last week that his company had no plans for an ARM-based MacBook, adding that the iPad will satisfy the needs of anyone who would have been interested in a potential ARM-based MacBook Air. Apple's desire to keep the Air high end could mean they'll stick with more powerful Intel chips for their laptop ranges.
Still, with ARM gunning for the high-performance territory as well as the low-power corner of the chip market, it's up in the air. ®