Xok (developed by MIT LCS Parallel and Distributed OSes group) is an OS based upon the idea of an "exokernel" (much like the no-kernel idea behind Tunes: there is no more runtime kernel in the OS, which yields up to 10000% performance gain).

Also see Dawson Engler's page (now at Stanford), and the various Exokernel and networking papers.

This page is linked from: Aegis   Microkernel   Microkernel Debate