Also see: Virtual machine | Emulation | x86

Homepage: http://www.cl.cam.ac.uk/Research/SRG/netos/xen

License: GPL

Xen is a virtual machine monitor, or an operating system contained inside another, for x86 that supports execution of multiple guest operating systems with unprecedented levels of performance and resource isolation. It requires a part of the kernel to be modified. Works on Linux 2.4 and 2.6, FreeBSD, NetBSD and Plan 9. The guest OS requires no modification of source code. A port of Windows XP was developed for an earlier version of Xen, but is not available for release due to licence restrictions.

Here is a performance benchmark between VMware and UML (User-Mode Linux).


According to the benchmarks on the site, it is much faster than both VMware and UML with only a 10% overhead. A disadvantage of Xen is being part of the host OS kernel needs to be recoded or patched. Also, VMware is a commercial and closed source app and UML is made to only run Linux inside of Linux solely.


TakeDown.NET -> “Xen