Wow.. I thought the iPhone/iPod touch were pushing ARM and BSD out with their 37 million units. But ARM goes through 1.3 billion units every quarter? That's huge.
ARM is in everything. Since their architecture is so flexible, they have solutions for the simplest needs as well as the more complex (netbooks). Anything you look at, from MP3 players and cell phones to flash controllers have a very good chance of having an ARM processor in them.
ARM is hugely popular on portable hardware. ARM processors are everywhere: consider that each Nintendo DS has 2 ARM processors, and that's sold 100m units alone.
I wonder how much of the NT codebase is still portable. Back in the "early days" you could get NT for MIPS and Alpha (http://en.wikipedia.org/wiki/Windows_NT#Supported_platforms) but I don't think Microsoft is willing to make a ARM version of Windows v.Next. This seems to be a pretty huge roadblock for manufacturers of these netbooks. It's my opinion that to remain mainstream and continue to sell large numbers of units they (Asus, MSI, etc) will have to offer Windows on every model.
Windows NT also supported PowerPC (the CPU was switched to little-endian mode on boot).
I'm sure they could support ARM for the base Windows OS, but lack of application compatibility would mean a lot of user confusion that would only damage the brand. ("It's called Windows, it looks like Windows, so why doesn't anything happen when I insert the install CD for FooApp from 1999?")
Emulating x86 on ARM wouldn't do much good either. Apple was able to pull it off for their PPC->x86 transition because the new CPUs were substantially faster and memory had become abundant. ARM-based netbooks don't have either of those benefits (if the budget for these machines allowed big CPUs and lots of memory, they would just use x86).
I think the power benefits of ARM, and the resultant loss of Windows compatibility, will the nudge to allow netbook makers to rethink what they're trying to achieve.
It's clear now that the iPhone isn't a phone, it's a tiny, handheld, portable computer. A computer for which both Windows and Office are meaningless, it's all about the browser. Netbooks could be something similar, just a bit larger, but not while they're tied to the boat anchor of being hardware compatible with XP even when you're running Ubuntu or Android on it.
