VM was a "hypervisor". That is it wasn't really an operating system but an environment whereby multiple operating systems could run on a single machine, each with protected access to the full instruction set and, most importantly, protected from each other. You could crash and burn your private virtual machine and everything else kept on running without a hitch. I can't recall the number of batch jobs I killed because a problem with a program in one partition in DOS/VSE caused the whole machine to crash.

I say "was a hypervisor". Firstly it was an OS in it's own right and thus is more than a hypervisor and secondly it's still around to the point that it'll run Linux as a client operating system. But my experience was from afar, I left the mainframe world and never got to work with it full time.

But now I have my own little virtual world. A while back Microsoft bought Connectix and their virtual machine technology. Oh, I'd tried it along with VMWare a while back and frankly it didn't do much for me either because my hardware wasn't up to it, the software wasn't robust or a combination of both but recently I picked up the latest version of Virtual PC from Microsoft and wow, how the worm has turned, Virtual PC 2004 has come into it's own.

What does it do? Firstly it installs in Windows XP Pro or Win 2k Pro just like any other program. Once set up you're ready to create as many virtual machines as you can find.

A wizard is available to walk you through the set up but it's hardly needed. You set up the amount of RAM and hard drive space you want to allocate to the "guest" operating system and start preparing the virtual machine like you would a regular computer. This might mean partitioning the hard drive, formatting it and then installing the operating system.

What operating system? Doesn't seem to matter. It took more time to track down old floppies than it did for me to install Windows 2003 server, FreeDOS, BSD and DOS 7.0.

Fire up Virtual PC and a console comes up that allows you to select an existing guest operating system or install a new one:

Click to enlarge

What you're seeing is a regular old XP Pro desktop with Virtual PC running Windows Server 2003 (running Internet Explorer) in the lowest position, a DOS VM running Windows 3.1 playing solitaire in the top right position and in the top left is the Virtual PC program console. Want a larger playground? No problem, you can enlarge any virtual machine to full size.

So what? Well it's pretty cool to be able to isolate various operating systems so you can do just about anything yet not have your main machine crash and burn. You can set up a virtual machine just like it's a real computer with it's own IP address, installed programs, anything you can thing of.

Want to try and trash your little virtual machine? By all means do so with no worries, you are isolated from the host operating system and won't bother it. In fact you're so isolated your virtual machine will need to have all patches, anti-virus software, etc. installed just like it was a new standalone machine.

Other than the obvious benefits to developers there's also the legacy aspect of all that great (okay, maybe not so great) DOS software that's still out there. If you've ever wanted to experiment or, if you're a refuge from the old days, experience some of the old stuff again without trashing your current system Virtual PC is the way to do it.

Performance on a perky AMD 4200+ system was brisk. Oh, Windows Server 2003 wasn't as fast as it would have been had it been the only thing running but it was certainly acceptable. Everything else was certainly faster than any hardware I'd used it on before, certainly far, far faster than say an 80286 so it seemed remarkable quick. I did have one session in Win 2003 where I dropped a few characters from the keyboard and from time to time I'd have to tell DOS that there was indeed a floppy in the drive two times (a pain when installing the 8 disk Windows for Workgroups update to Win 3.1) but nothing terminal.

There are troublesome questions; will the police break down your door if you set up a virtual copy of XP Pro using the same copy of XP Pro that's hosting Virtual PC? Read your EULA but Microsoft has announced that they will allow "virtulizing" Windows Server 2003 R2 Enterprise and the Datacenter edition of "Longhorn". Sadly they haven't made any changes to the desktop software license that would allow virtualization.

But there's still plenty of stuff to plink away at and you can try Virtual PC for 45 days for free. List price from Mr. Softie is $129*. I've seen it discounted at several places and, as always, be sure to check around for the best price. Meanwhile if you want to check it out you can download the trial version off the Microsoft info page here.

*Since writing this article my opinion of Virtual PC hasn't changed and I continue to use it daily. One new development is that Microsoft is now giving away Virtual PC for free. It can still be obtained at the link above.

And my biggest problem? Finding a 5.25" diskette drive for all that old software....