A compiler for a substantial subset of PL/I for the Univac 1100, from the University of Maryland.
["PL/I Programming with PLUM", M.V. Zelkowitz, Paladin House, 1978].
(1995-02-23)
Try this search on Wikipedia, OneLook, Google
Nearby terms: Pluggable Authentication Module « plugh « plug-in « PLUM » Plumber » plumbing » Plural EuLisp