Could you please share 'your insight' on the
'set of virtualization problems' that Xen solves ?
Xen lets you run multiple versions of modified OSes on the same box.
Each OS for the most part can treat its small pool of resources as its
own. It hides the underlying hardware from the virtual domain
(although its apparently quite popular to break out bits of hardware
to appear in the virtual domain.)
The Xen paravirtualisation stuff in -theory- should be more
lightweight than full hardware virtualisation and it should perform
better. In practice? That's very much workload dependant.
Xen also lets you write "other" OSes without needing to care about the
hardware. One of my friends bootstrapped a toy OS of his inside Xen.
He can then run it on any and all Xen boxes, unmodified, regardless of
the underlying hardware. That really hasn't been exploited to its full