re: Microsoft Windows 8 Unification Plan: Grand, But Risky
"But that doesn't make it any less true that the Windows client, to date, has never officially run on anything except Intel processors or x86 and x64 clones."
...technically true, but very misleading. "Client", of course, refers to the mainstream consumer-branded Windows. But that's missing the point. Even our modern Windows 7 and the upcoming 8 are NT-based operating systems. NT kernel, network stack, security model, process model, drivers, etc.
And anybody who has done their homework knows that the NT family was developed on the ill-fated i860 platform, and was then ported to other architectures including PowerPC, MIPS, DEC Alpha, and (of course) x86.
Naturally, only the x86 and derived x86-64 variants, along with IA64, survive into the modern day. But let's make no mistake about this- the underpinning for a multi-platform OS is already in the Windows codebase. Hence the Hardware Abstraction Layer, among other things. MSFT will have to do a good deal of work to get ARM support going, but they aren't having to reinvent the wheel here.