L4, a family of *(OS)es originally by
_(Jochen Liedtke|http://l4ka.org/team/liedtke.jpg)
(R.I.P., was chair of the <A HREF="http://i30www.ira.uka.de/index.php">System Architecture Group</a> at the University of Karlsruhe)
are *(microkernel)s to demonstrate how optimizing performance requires
_(OS) _(kernel)s to be completely hardware-dependent, and even _(CPU)-version
dependent in a same family of _(CPU)s.

<ul class="links">
<li><A HREF="http://l4ka.org/">L4/Ka - The L4 microkernel family and friends</a>
at <A HREF="http://i30www.ira.uka.de/">System Architecture Group</a>, University of Karlsruhe
<li><A HREF="http://os.inf.tu-dresden.de/L4/">The L4 -Kernel Family</a>
at <A HREF="http://os.inf.tu-dresden.de/">Operating Systems Group</a>, TU Dresden.
</ul>
