Denali (operating system)
The Denali operating system is "an IA-32 virtual machine monitor, that allows for untrusted services to be run in isolated domains."
Denali makes use of paravirtualization to support high performance virtual machines, even on the notoriously uncooperative x86 architecture. The envisioned usage model for the original Denali was to support virtual machines running lightweight single application operating systems for internet services. A later revision of Denali includes support for running full-featured operating systems.
