Version 7

Version 7 alt. V7 /vee' se'vn/ n.  The first widely
   distributed version of {UNIX}, released unsupported by Bell Labs
   in 1978.  The term is used adjectivally to describe UNIX features
   and programs that date from that release, and are thus guaranteed
   to be present and portable in all UNIX versions (this was the
   standard gauge of portability before the POSIX and IEEE 1003
   standards).  Note that this usage does *not* derive from the
   release being the "seventh version of {UNIX}"; research
   {UNIX} at Bell Labs has traditionally been numbered according to
   the edition of the associated documentation.  Indeed, only the
   widely-distributed Sixth and Seventh Editions are widely known as
   V[67]; the OS that might today be known as `V10' is instead known
   in full as "Tenth Edition Research Unix" or just "Tenth
   Edition" for short.  For this reason, "V7" is often read by
   cognoscenti as "Seventh Edition".  See {BSD}, {USG UNIX},
   {{UNIX}}.  Some old-timers impatient with commercialization and
   kernel bloat still maintain that V7 was the Last True UNIX.