Virtual Box is a community delovped project, by SUN for the purpose of OS Virtualisation. That is, any other operating systems can be booted inside other operating systems inside a virtualisation window. The Virtual box software will manage the resources required for the newly booted software and the currently running software. It will allocate the free resources within itself, to boot the new operating system virtually.

Presently, VirtualBox runs on Windows, Linux, Macintosh and OpenSolaris and many other guest operating systems. So this includes almost all most frequently used operating systems.

With Virtual box you can boot Guest operating systems in USB, Portable hard drive, or ISO images of operating systems in any host operating system. That is you can boot the downloaded iso images of opertaing systems(linux) in live -cd mode without burning them to a cd.

Rosario Applications, Ubuntu, Virtualisation Ubuntu, VirtualBox