quite extensive overview » http://www.ntlug.org/~cbbrowne/lisposes.html

Movitz is a dev. platform for LISP like OSes, currently with a kernel, Cross Compiler for x86 based metal. “The Movitz system aspires to be an implementation of ANSI Common Lisp that targets the ubiquitous x86 PC architecture 'on the metal'. That is, running without any operating system or other form of software environment. Movitz is a development platform for operating system kernels, embedded, and single-purpose applications.” http://www.cs.uit.no/~frodef/los0/

see: Lisp Machine