_(Andy Tanenbaum)'s <A HREF="http://www.cs.vu.nl/pub/amoeba/"
  >Amoeba</A>, the reference among _(distributed) *(OS)es, is now free. To take full advantage of its _(distributed) programming model, related _(programming language) <A HREF="http://www.cs.vu.nl/vakgroepen/cs/orca.html"
  >Orca<A> has been codevelopped.