Xok (developed by MIT LCS Parallel and Distributed _(OS)es 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 <A HREF="http://www.stanford.edu/~engler/"
  >Dawson Engler's page</A> (now at Stanford), and the various
<A HREF="http://www.pdos.lcs.mit.edu/PDOS-papers.html"
  >Exokernel and networking papers</A>.
