UNIX or Unix

[dmr at alice.UUCP]

The Chicago Style manual advocates spelling trademarks with an
initial cap.  Common usage prefers not to spell words, except
acronyms or other abbreviations, in all caps.  The U word is
a trademark and it is not an acronym.

Ownership of a trademark permits the owner to keep others from
using that mark in trade.  It doesn't generally give the owner legal
rights over permissible English usage.

If you are offering a U product, you had better be sure that your
usage of the term (particularly in advertising and other sales
literature) complies with AT&T's requirements, because
you are using it with their permission.  If you are writing
ordinary English discourse, you may treat requests from AT&T as
indications of AT&T's preference, and decide for yourself
which form you prefer, and whether AT&T's opinion of your
English matters to you.  (If you are an AT&T employee, it
might well matter.)

Similarly, a footnote or other mark is, for most people, a matter of choice.
Few general or trade publications decorate trademarks.
Some do; but it would be thinkable for ACM (say)
to decide, as a matter of style, to forbid the decorations.
They would surely get letters from AT&T and others, and it would
be perfectly safe to write back saying "Thank you for your opinion."

			Dennis Ritchie