Recently I have successfully finished the task of virtualizing Windows XP under my Windows 7 OS in my Thinkpad X60s. Since I'm fond of installing XP stuff for the sake of nostalgia (after a failed attempt to make Ubuntu look like XP), I knew adding Windows XP to my boot configuration would be unnecessary, so I turned to virtual machines.
What are virtual machines?
Virtual machines are non-physical computers running instructions inside a host computer, similar to a real, physical machine. In layman terms, it's like Inception: a computer within a computer. This is very useful for testing compatibility issues, like testing if your Windows 7 program could work on earlier versions of Windows without using another computer or installing the OS on a separate partition. You can go as many virtual computers as you like, so long as your hardware capabilities can permit. You can have like a computer within a computer within a computer within a computer, and so on.
Disadvantages of virtual machines
Virtual machines will always grab a chunk of the host OS's resources. This means your host OS (the real computer) should have some spare resources to give to the guest OS. Processing power isn't really that much of a requirement, unless you're installing a modern operating system like Vista, 7, or OSX. But memory is a must, and for virtual PCs, 2GBs of RAM or more is recommended.
Also, it can't run as fast as a real operating system can. But it can do whatever a real OS could do.
Cool stuff about virtual machines
One of the most important traits a virtual machine possesses, is that, it is not directly linked to your host OS. It only runs inside the host OS, but it rarely directly communicates or shares files with the host OS unless you set it to. This means that whatever happens in your virtual machine stays in your virtual machine. This is great, because if your guest OS catches a virus, it stays there and it will never infect the host OS unless the guest has privileges to write to a shared folder on the host OS.
You can use the guest OS as a sandbox, go to sites you never dare to visit lest your computer gets messed up, and see what happens. If the guest OS gets nuked by malware and whatnot, don't panic. You can always just remove it and install another one, provided you don't have much sensitive data on your guest OS.
On a side note, virtual machines could be excellent for trolling, as it adds an extra layer of anonymity and protection. Combine that with a good relaying service, some proxies, and good privacy ethics, and you're good to go as a faceless person on the Internet, e.g. a complete Anon. Just don't troll too much, ok?
What you'll need for a virtual machine
- Some spare RAM (256MB+ recommended)
- At least 8GB of HDD space
- A (hopefully genuine and legal) copy of your preferred guest OS
- Time
I used some Windows XP disc I found lurking in my disc archives, it was marked as "Service Pack 3" for the lulz, as I recall I have bought it sometime around 2006. Now remember that the SP3 for Windows XP didn't come until recently in 2009 or so. But this copy was good - uxtheme.dll was already patched, so it had custom themes of its own, it included a basic suite of Microsoft Office 2003, and 2005 versions of Adobe Reader, Mozilla Firefox and Winrar. At least there aren't any bloatware.
