VirtualBox is one of the most useful virtualization software available for free.
Creating virtual machine is easy, just a few clicks and we are able to explore new operating system. What we need to sacrifice is some processor time, RAM memory and a few GBof hard drive. These resources can be dynamically allocated, even the hard drive.
Recently, I had set up a developement environment on a virtual machine running Windows 7. Hard disk has been dynamically allocated at 30 GB. I was running GlassFish server with MySQL database and Eclipse IDE. I also had installed ruby with rails framework along and Aptana Studio. As you can imagine VHD become insufficient. As I couldn’t afford to install everything from scratch again, I decided to extend virtual disk.