NAME

       ditroff - classical device-independent roff

DESCRIPTION

       The name ditroff refers to a historical development stage of the roff(7) text processing system.  In roff
       systems extant today, the name troff is a synonym for ditroff.

       Early versions of roff by Joe Ossanna generated two programs from the  same  sources,  using  conditional
       compilation  to  distinguish  them.   nroff  produced  text-oriented  TTY  output,  while troff generated
       graphical output for exactly one output device, the Wang Graphic Systems CAT phototypesetter.

       In 1979, Brian Kernighan rewrote troff to support more devices by creating an intermediate output  format
       for  troff  that  could  be fed into postprocessor programs which actually do the printout on the device.
       Kernighan's version marks what is known as “classical troff” today.  In  order  to  distinguish  it  from
       Ossanna's original version, it was called ditroff (device independent troff) on some systems, though this
       naming isn't mentioned in the classical documentation.

       Today, all existing roff systems are based on Kernighan's multi-device troff.   The  distinction  between
       troff  and  ditroff  is  no  longer  necessary;  each modern troff provides the complete functionality of
       ditroff.

       The easiest way to use ditroff is via the GNU roff system, groff.  The  groff(1)  program  is  a  wrapper
       around (di)troff that automatically handles device postprocessing.

AUTHORS

       This document was written by Bernd Warken ⟨groff-bernd.warken-72@web.de⟩.

SEE ALSO

       CSTR #54
              refers to the 1992 revision of the Nroff/Troff User's Manual by J. F. Ossanna and Brian Kernighan.

       CSTR #97
              refers  to A Typesetter-independent TROFF, by Brian Kernighan and is the original documentation of
              the first multi-device troff (ditroff).

       roff(7)
              provides a history and conceptual overview of roff systems.

       troff(1)
              describes the GNU implementation of (di)troff.

       groff(1)
              documents the GNU roff program and includes pointers to further documentation about groff.

       groff_out(5)
              describes the groff version of the  intermediate  output  language,  the  basis  for  multi-device
              output.