Over the past year and a bit, I've begun playing with Virtualization on my PC. The reason was mainly because I got very tired of having to rebuild my OS when I inevitably got it so cluttered with garbage that it drove me crazy. I'm not talking viruses or other malware, just programs reminants from a variety of shareware and other software installs and uninstalls.
I started with a very brief trial of VMWare Workstation, but gave up on it quickly at the time as I thought it was overkill for what I needed. In fairness, I was actually struggling with the concept of virtualization, and why I'd even need it. After about couple more OS rebuilds, though, I gave it a shot again. VMWare was again the product of choice, and I became a big fan of the snapshot feature.
For those of you who have never used VMWare Workstation, (or any other Virtual Machine software,) you basically install another operating system in a sandbox. So for me, I was running Windows XP on my laptop, and I created a separate copy of Windows XP in a VMWare session. It's completely separate from your original install, so you can do whatever you want to it, without worry of messing up your host OS.
Now the snapshot feature allowed you to install the base virtual OS, and then manage an entire tree of snapshots. So I was able to create a nice clean Windows XP install and take a shot there. From there I was able to create several spinoff images. Let's say it looked like this:
|---> Base + Office 97
|---> Base + Office 2000
|---> Base + Office 2003
|---> Base + Office 2007, Beta 2
|---> Base + Office 2007, Beta 2 + Tech Refresh
At this point, if I wanted to install a totally non office related application, I'd go back to the base snapshot, install the app I wanted, and I'd have a new snapshot with Base + MyApp. All in all a very cool feature.
This was all very good, but one big issue arose when I migrated to Vista... VMWare Workstation does not seem to play very nicely there yet. 🙁
With the upgrade to Vista, it became even more important to me to have a virtual system on my development PC. I'm now running Office 2007, but I will still need to develop and test applications to work in prior versions of Office, and on the Windows XP platform. (I'm not supporting apps on anything earlier.) So far, the only product that I've found that makes the Vista cut is Microsoft's own Virtual PC 2007 Beta.
I can't say much about the product, as I've only been using it a couple of days, but it does not have the snapshot feature that I love so much in VMWare. It does have Microsoft's own flavour of it though, called "Differencing Disks", which sounds similar. The help files are kind of weak on it, but someone pointed out an Excellent article on this feature which explains it much better than I could.
For reference, Virtual PC 2004 is free to use, as the 2007 version will be too.
One other (Free) product worth mentioning here is SVS Juice. This is not a full OS virtualization package, but rather just an application that installs as a sort of layer between your OS and the applications. Any time you want to install a new app, you can create a new layer and install the app into it. You can then activate or deactivate the application at will.
As a case study, let's assume that you get a new game from your brother. You want to try it out, but it needs an install and you're pretty sure you won't want to play it very often. This is the perfect situation for SVS Juice. You create a new layer, install the game, and can play it to try it out. Once you're done, you deactivate the layer, and all the registry keys and disk changes that it made are rolled up into a little package and stored away. They are no longer interfering with your system, and should you choose to delete the layer, will not be left behind.
I used SVS Juice to install any kind of trial software, just to avoid the left over garbage if I didn't want to keep it.
Granted, it doesn't work with everything, and it can be confusing when a file you made that day disappears, or if you want to update layers, but you can get used to it. The sad thing is that it also does not work on Vista yet. 🙁
If you are on XP though, I'd highly recommend checking it out.