VirtualBox is free, Open Source virtualization software that allows users to run multiple virtualized Linux, Solaris, BSD, OS/2 and/or Windows systems at one time. Each virtual machine runs as a guest on the host system, which can also be Linux, Solaris or Windows.
Virtualization can be used for many reasons. It can be used to maximize usage of hardware capital resources by running multiple virtual computers on a single piece of hardware. It can be used to provide secure, isolated virtual environments for varied types of software, such as in a development environment where you may wish to do development one one virtual machine and testing on another, both of which are hosted on the same physical computer.
This section discusses various solutions to problems I have encountered while using VirtualBox.