Ok, back to the ARMv6 vs v7a issue. I'm not sure what all these press releases about 'porting Ubuntu to ARMv7' is really about. I don't know a single Ubuntu (or Debian or any other distro) application which relies much on assembly. They're all written in C, or C++, or occasionally some other high level language.

So, what all of those applications rely on in order to get good performance out of a particular CPU is just this single question: "Did somebody add support for ARM v7a optimizations to GCC already?". If yes, then you can choose to optimize for your architecture of choice by using a particular compiler flag. And potentially make the executable incompatible with older (e.g. ARM v6) architectures.

The real porting to a new architecture goes on in A) the compiler suite, as mentioned above, and B) in the kernel. Not in the distro. Ubuntu is a distro. The kernel porting is done by all those folks (including Nokia, and other companies) contributing to the kernel in general, and linux-omap in particular (for our omap-based ARM devices).

So what does it mean when they say "porting Ubuntu to ARM"? It doesn't make sense. "Ubuntu contributing to ARM Linux kernel development", or "Ubuntu supporting work on the GNU Compiler Collection" would make some sense. "porting Ubunto to ARMv7" does not.