From: Mike Leo <mleo963@yahoo.com>
A pleasant correction...
Mac OSX is a BSD derivative, not Linux, though they are similar.
I am pretty sure that OSX uses the Mach microkernel, the same one used by the GNU Hurd, and which was developed by Rick Rashid et.al. at CMU in the 1980's. Last I knew Rick took a job at MS as Director of Research, or something like that. I know these things because I was a small part of the et.al. mentioned above. Mach was meant as a base on which to build a Unix-like OS, and FreeBSD had a large influence on how Mach was turned into OSX. I don't know if there is actual code from FreeBSD in it. (Apple has been lax in telling me before they do anything.) Many "Linux" programs, many of which are really GNU programs, run on OSX. -- Keith