I used to think that virtualisation was only for people running server farms, or for Mac users wanting to also run Windows. After trying out VirtualBox for the past few weeks I have discovered that could be useful for a far greater range of users.
In 1996 I partitioned my hard disk into separate Windows and Linux areas for the first time. This was to enable me to dual-boot, so I could work on programming my honours project in Linux at home, instead of squeezing onto one of the shared Sun SPARCstations at Uni. Since then I always had at least two partitions, reaching a peak of four operating systems: Windows 98, Windows 2000, Linux (probably Mandrake) and BeOS. I always had a FAT partition that all OSes could see, so I used that as a shared area. This was the way things were until VirtualBox, and a better way presented itself.
The major benefit of VirtualBox is that multiple OSes can be run simultaneously. If I'm in Windows and I want to compile some code in Linux I just need to run the VirtualBox application and start my Linux virtual machine. I can continue doing my Windows work while Linux boots in another window. When it has loaded data can be shared in specific folders, or copied via the clipboard.
Anything that happens in the virtual machine is completely independent of the WIndows "host" system. This makes it great for testing software. Just set up a Windows "guest", make a snapshot, then test away. If you damage the virtual Windows then you can easily revert to the snapshot. Whilst I run Windows XP as my main OS, I have a Windows 2000 and Windows 7 virtual machine for testing. If I want to see if the new RealPlayer is as intrusive as the old versions I can install it in the Windows 2000 virtual machine, and leave XP pristine. As I mentioned previously, Windows 7 ran games too slowly, so I couldn't switch to it full time. VirtualBox lets me play with it without the hassle of setting up a separate partition, and without having to reboot when I want to test a new feature that I've just read about in LifeHacker.
VirtualBox is surprisingly fast. My Windows Experience Index only deteriorated in the area of graphics when comparing VirtualBox with a proper installation. This is not unexpected, because VirtualBox does not yet support Direct3D (though it does do OpenGL acceleration).
Virtualisation has a bright future. Before I purchase my next CPU I'm going to make sure that I get one with built-in virtualisation features, because I know that I'll be a committed virtual machine user for many years. I can't wait for the next VirtualBox release.