Unix without tar?

[Joe Smith]

Recently, someone asserted that tar archives aren't a suitable
distribution format because they aren't understood by every Unix.

Given some reasonable constraints of their contents (ascii files,
names < 14 chars), is this true?  Doesn't every Unix have tar?  I know
there has been some (d)evolution of tar, but aren't simple archives
still portable?  With the availability of GNU tar (and others ?)
which are portable enough to run on other OS's, I found the assertion
hard to believe, but I couldn't refute it.

<Joe
--
 Joe Smith
 University of Pennsylvania                    jes at mbio.med.upenn.edu
 Dept. of Biochemistry and Biophysics          (215) 898-8348
 Philadelphia, PA 19104-6059