VirtualBox 5.0.20.106931 portable | 140 Mb
VirtualBox is an application installed on an existing host operating system; within this application, additional operating systems can be loaded and run, each with its own virtual environment. For example, several Linux distributions can be hosted on a single machine running Windows XP; likewise, XP and Vista can run on a machine running Linux, and so on. There is a free for personal or evaluation use proprietary version and a GNU General Public License (GPL) version.