Source : Free On-Line Dictionary of Computing

Early PL/I
     
         (EPL) A {PL/I} subset dialect by McIlroy, Morris et
        al, the first running PL/I {compiler}.  It was used by {Bell
        Labs} and {MIT} to write {Multics}.  EPL had extensions to
        handle the segment/offset nature of {Multics} pointers.
     
        See also {REPL}, {TMG}.
     
        ["EPL Reference Manual", Project MAC, April 1966].
     
        [Sammet 1969, p. 542].
     
        (1995-11-15)