"In just a few short months, an open-source software package
called Xen has been catapulted from obscurity to the limelight as
many computing industry powers throw their weight behind the
"Xen lets multiple operating systems run on the same computer, a
feature that's useful for extracting as much work as possible from
a single system. The technology is common among high-end servers
today, but on mainstream systems it requires proprietary 'virtual
machine' software from EMC subsidiary VMware..."