The Free On-line Dictionary of Computing (30 December 2018):

BSD/OS

    BSDI's commercial version of Berkeley
   Standard Distribution Unix.  BSD/OS is a
   POSIX-compatible, Unix-like system for the 80386, 486,
   and Pentium.  It is based on the BSD software from UCB,
   a number of other sources, and components engineered by BSDI.
   The initial production release of BSD/OS shipped in March,
   1993.

   (1996-01-13)