There’s some intriguing news today as a secret experiment has come to light regarding Apple’s Mac OS X Snow Leopard and plans to port it to the ARM architecture. Last year Microsoft also announced its intention that Windows 8 would run on the ARM architecture.

The news of the Apple experiment is particularly interesting after revelations last week whereby earlier speculation of using ARM-based processors in MacBook Airs laptops, seemed to have been dismissed by Apple CEO Tim Cook. The mystery project involving porting OS X Snow Leopard to the ARM architecture was written about in a thesis by former Apple intern Tristan Schaap in 2010. He worked for 12 weeks as an intern in a subdivision of the Core OS department, Apple’s Platform Technology Group, and is now working for Apple as a Core OS engineer. After initially being kept under wraps the academic paper has now been published by the Delft University of Technology in the Netherlands as detailed here.

A summary of the paper in this article tells how Schaap worked with a group of others to get the ‘lower half’ of Apple’s MAC OS X operating system, Darwin, to boot onto Marvell’s ARM processor. This was eventually achieved although not to full effect due to debug hardware issues. Whether the results of the experiment were ever intended to be used in Apple devices is not known but there were three main technical issues to confront, including creating a build system, a stale kernel source and problems with the JTAG bugger. Ultimately any product to be shipped needed more work on the L2 cache and to be used with full potential it was felt it would be necessary to write more drivers.

Last year a rumor surfaced of a MacBook Air prototype using the same ARM-based A5 processor of the iPad 2, which Apple executives apparently said performed “better than expected.” However as that idea now looks to have been scuppered by Tim Cook, who feels an evolved iPad would meet those needs, an A6-powered MacBook Air now looks highly unlikely. Although Microsoft declared that ARM architecture would be used for Windows 8, where its intentions differ from that of Apple’s is that Microsoft tablets are planned using a full desktop OS with a touch-optimized UI layer on top whereas Apple’s intention was taking the iPad tablet’s ARM-based processor to the MacBook Air.

Although it doesn’t look as though an ARM-based processor will be used yet for the MacBook Air then, it’s certainly possible down the line. Another take on this can be seen here where the author feels it’s “more than likely that sooner or later the entire Apple ecosystem will run on ARM.”

We’d like to hear your thoughts on this. Do you think Apple seriously intends to change its architecture again? Let us know by sending your comments.

Tags: ARM, Mac OS X