Operating System Design/Case Studies/XOK
XOK is the newest research exokernel to date. XOK was created by a computer science research team at MIT. XOK is able to compile most UNIX programs (perl, gcc, emacs, etc.) with little or no change, and has equal to or greater speed than FreeBSD when using standard libOS's. However, when using specilized LibOS's, XOK is able to get great performance boosts. The greatest of which has been the Cheetah web server, running at eight times its normal speed on FreedBSD or Linux.