Fascinating piece by Charles Arthur in the Guardian pondering the implications of revelations that Apple has been porting OS X to the ARM chip.

Written by Tristan Schaap, the paper describes working in the PTG [Apple’s Platform Technologies Group] for 12 weeks, porting Darwin to the MV88F6281 – an ARMv5-compatible processor that’s a couple of generations old now. They were then porting Snow Leopard, aka 10.6; Mac OS X is now onto 10.7 (“Lion”), released last year.

“The goal of this project was to get Darwin building and booting into a full multi-user prompt,” Schaap wrote in the introduction that’s generally visible on the DUT page.

But in the paper he goes significantly further: “The goal of this project is to get Darwin into a workable state on the MV88F6281 processor so that other teams can continue their work on this platform.” Emphasis added. That tells you: Apple is working on porting Mac OS X to ARM, and thus giving itself fresh options if the ARM architecture – known for its low power demands, but equally not until now seen as a competitor in processing heft to Intel – starts offering the horsepower users need.

And there have been indications that ARM is moving up the horsepower ratings, even while Intel tries to lower the floor on its chips’ power consumption.