Pax

pax (Portable aRchive eXchange) is an uncompressed archive file format, and a multi-format archiving utility. The file format is rare, and some versions of the pax utility do not support it.

Specifications

 * Format of pax archives

Links

 * Wikipedia article (mostly about the pax utility)
 * pax man page, from a version of pax that supports pax format