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

pSather

    A parallel extension of Sather for a clustered
   shared memory model.  It features threads synchronised by
   monitor objects ("gates"); locality assertions and
   placement operators.

   There is an implementation for the CM-5.

   ["pSather Monitors: Design, Tutorial, Rationale and
   Implementation", J.A. Feldman et al, TR-91-031 and TR-93-028,
   ICSI, Berkeley, CA].

   (1995-03-13)