Who's the host, and who's the guest?

So there's this big announcement today that Microsoft Open Sourced some Linux drivers: specifically the drivers that make Linux run well under Microsoft's hypervisor.

Great, right? This is the new, open minded Microsoft, right?

Well, sort of. It's also the same old Microsoft. While we're all caught up in making Linux better, they're focusing on the real question about virtualization: which one is the host, and which one is the guest?

Because the answer to this question defines whether Microsoft gets to keep their monopoly or not in the long run. Cool, huh?

Look at it this way: right now, 100% of the Windows apps I need to run run just fine on Windows XP. And Windows XP runs just fine under virtualization. In fact, my Linux box + Virtualbox + Windows XP runs faster than Windows Vista. (And Windows 7 is dodging the question by running XP in virtualization anyway.)

In fact, because my virtual hardware can stay the same forever even if my physical hardware gets upgraded, a virtual Windows XP actually has a potentially longer lifespan than a physical one. After all, I can still run Windows 98 under Win4lin under kvm and it'll work forever.

Microsoft's vendor lock-in is all about the fact that you need the new version of Windows to run your apps. They've already started pressuring vendors to stop making XP drivers for their new devices - and it'll get much worse with Windows 7.

But with virtualization, maybe you'll just keep your copy of XP - just about everyone in Canada and the U.S. has one or more legal copies of XP at this point - and run it under whatever OS you want. Suddenly, no more vendor lock in. You can choose whatever OS you want to run on your PC - or Mac - and you don't lose. In fact, you could probably make a business model out of just making a stripped-down Linux kernel designed just to run a virtualized XP, only with updated drivers.

So the question, then is: which OS will you choose, now that you have the choice?

Well, which one is better for virtualizing all the OSes I might need to run?

As of the recent announcement, Windows 7 can run Windows and Linux VMs really fast. Linux can run Linux VMs really fast, but it can only run Windows at "normal speed." (Xen actually built accelerated drivers for Windows too back when it was a research project - but Microsoft cut them off eventually, IIRC.)

You know what? Most people will probably choose Windows 7 as their host anyway, just out of habit. But habits can change over time. Microsoft needs you to have a better reason than just that.