Do you choose applications or operating system first?

According to The Register, XenSource have demonstrated Windows XP running on their virtualisation software (as opposed to running a *nix operating system). This is software that allows you to run multiple operating systems on one machine simultaneously, without having to reboot to change from one to the other.

I run VMware on my PCs, including my laptop. That means I can run Windows when I need or want to, or a *nix, including Solaris. It's great to have that kind of choice. When Apple moves from PowerPC to Intel processors, I would be brilliant if I could run OS X as well.

Which brings me back to the classic question, do you choose your applications first, and then an operating system which will run them, or do you choose the operating system first, and then the applications? If you are lucky enough to have this choice, I think there is a new answer:

1. Choose the applications you need first (if possible);
2. Choose the virtualisation software that can run the different operating systems you need for those applications;
3. Choose enough operating systems to run those applications with your virtualisation software.

It's an incredibly liberating thing, not to be tied to one operating system any more. So good news to see vendors giving us choice. Combined with the virtualisation support being added to processors by AMD & Intel, things are looking pretty darn good, as they say.