What is Xen? on Linux virtualization

Xen is an open-source virtualization solution.  The Xen hypervisor acts as a thin layer between the hardware and the operating system, allowing multiple virtual servers to run simultaneously on a single physical server.  Each virtual server acts independently of the others, with its own allocated area of RAM and virtual disks.

For more information, see the Xen website, http://www.xensource.com/