Source : Free On-Line Dictionary of Computing

troff
     
         /T'rof/ or /trof/ The grey eminence of {Unix}
        text processing; a formatting and phototypesetting program,
        written originally in {PDP-11} {assembly code} and then in
        barely-structured early {C} by the late Joseph Ossanna,
        modelled after the earlier {ROFF} which was in turn modelled
        after {Multics}' {RUNOFF} by Jerome Saltzer (*that* name came
        from the expression "to run off a copy").  A companion
        program, {nroff}, formats output for terminals and line
        printers.
     
        In 1979, Brian Kernighan modified troff so that it could drive
        phototypesetters other than the Graphic Systems CAT.  His
        paper describing that work ("A Typesetter-independent troff",
        AT&T CSTR #97) explains troff's durability.  After discussing
        the program's "obvious deficiencies - a rebarbative input
        syntax, mysterious and undocumented properties in some areas,
        and a voracious appetite for computer resources" and noting
        the ugliness and extreme hairiness of the code and internals,
        Kernighan concludes:
     
        None of these remarks should be taken as denigrating
        Ossanna's accomplishment with TROFF.  It has proven a
        remarkably robust tool, taking unbelievable abuse from a
        variety of preprocessors and being forced into uses that
        were never conceived of in the original design, all with
        considerable grace under fire.
     
        The success of {TeX} and desktop publishing systems have
        reduced troff's relative importance, but this tribute
        perfectly captures the strengths that secured troff a place in
        hacker folklore; indeed, it could be taken more generally as
        an indication of those qualities of good programs that, in the
        long run, hackers most admire.
     
        {groff} is {GNU}'s implementation of {roff} in {C++}.
     
        [{Jargon File}]
     
        (1995-03-21)