I've been playing around with Virtual PC for the last week or so at work. This is amazing. I know that the technology has been out for a long time, but I had never really used it before.

I have an XP virtual session that i run on my XP laptop. The other day I upgrade the XP virtual machine to run the latest Longhorn build. Very cool. In preparation for the PDC I was trying out some libraries that we were creating. So, I turned on the "Undo Disk" feature - basically you can run the session and then at completion choose to throw away all the changes to the machine, completely. Very cool.

I'm running Virtual PC in about the worst possible situation. Virtual PC runs the CPU at near 100%, network at 100%, but disk I/O at some much less that 100%... given that laptops have slow hard drives to begin with, this makes it pretty bad. On top of that, I'm running Longhorn - which is a not-even-alpha operating system right now. Longhorn is fairly video intensive, which makes Virtual PC's video driver (S3 emulation) get very stressed.

Even with this, I still find it to be such a compelling experience. The ability to host multiple OS on a single box (at one point I was running DOS 6.2, Redhat, and Windows XP at the same time!) is just amazing.

For me, Virtual PC is one of those must-have features for developers.