Date: 15 Oct 1995 00:00:01 EST

  When user A extracts a file owned by user B from a tar archive, 'tar'
  makes the file owned by user A unless user A is the superuser.  Some
  systems allow users to give files away (e.g. IRIX); some do not
  (e.g. SunOS).  On some systems with the restricted behavior (SunOS
  among them), 'tar' tries to give the file to user B whether or not
  user A is the superuser, assuming that the chown system call will fail
  if user A is not.  This is not true if user A is using 'tar' on (e.g.)
  a Sun to extract files onto a filesystem NFS-mounted from (e.g.) an
  SGI.  'tar' may create zero-length files or give away directories and
  then be unable to extract files into them.

  Work around the problem by doing the 'tar' on the SGI or extracting
  onto a Sun filesystem. It is possible that third-party versions of
  'tar' (e.g. GNU tar) are smarter; if so, let us know. You could turn
  the restricted_chown kernel variable on on the SGI, but be aware that
  some programs may depend on unrestricted chown, notably /bin/mail as
  discussed elsewhere in this FAQ.