A slight historical note:  Because of the AT&T ownership of the trademark,
people used to avoid using "UNIX," which led to some's shunning of
the "Unix file system" expansion.  These days, it's probably not as
important a thing to worry about.
--
Todd Masco     | "Roam home to a dome, Where Georgian and Gothic once stood
cactus@hks.net |  Now chemical bonds alone guard our blond(e)s,
cactus@bb.com  |  And even the plumbing looks good."  - B Fuller