A modern day operating system has been written in Lisp. If you're talking about x86, there is Movitz as proof of concept, but there is more to "operating system

A modern day operating system has been written in Lisp. If you're talking about x86, there is Movitz as proof of concept, but there is more to "operating system" than a bootstrapped self-hosted shell. http://en.wikipedia.org/wiki/Movitz http://en.wikipedia.org/wiki/Movitz Regarding high performance numeric code in CL, you have the whole of Richard Fateman's career and body of work to peruse. Recently, Didier Verna did a few awesome things: http://www.lrde.epita.fr/~didier/research/verna.06.imecs.pdf http://www.lrde.epita.fr/~didier/research/verna.06.imecs.pdf http://www.lrde.epita.fr/~didier/research/verna.06.labri-slides.pdf http://www.lrde.epita.fr/~didier/research/verna.06.labri-sli... There was an awesome report from a boutique audio shop that produces gear for audiophiles; they were doing some realtime stuff and they pushed LispWorks harder than anyone I know. Too bad can't think of their name atm.