Exokernel was basically a very early form of a hypervisor. It's not totally novel as hypervisors have been around for a very long time but what makes the Exoke

Exokernel was basically a very early form of a hypervisor. It's not totally novel as hypervisors have been around for a very long time but what makes the Exokernel interesting is that it doesn't try to run unmodified guests but rather runs paravirtual guests. It's basically a very early (pretty much a full decade) predecessor to Xen.