And my university (I think -- it's been a while) had some IDE controllers that did the same sort of revert-to original state thing that VMWare does. That is, any changes to the hard drive were made in some sort of scratch space, but when the computer was rebooted, the scratch space was deleted and the computer reverted to how it was the last time it was rebooted. Pretty nifty. I have no idea what the product was, but it worked very well.