Questions about dev. ind. troff

[Doug Gwyn (VLD/VMB)]

Device-Independent TROFF is a rewrite of TROFF to improve support
for a wider variety of typesetters; it was done by Brian Kernighan
some time ago and is distributed in two forms:
	Typesetter-Independent TROFF package from AT&T Bell Labs
	(The original packaging; includes tbl/eqn/refer/ideal/pic/-ms)

	Documenter's WorkBench from AT&T Software Sales & Marketing
	(Essentially the same TITROFF with a different complement of
	typesetter filters, minus refer/ideal/-ms, adapted for UNIX
	System V)
TITROFF is (or was) available directly from Bell Labs, unsupported.
DWB is available from AT&T, supported (you will probably need to work
on the device filter for your particular typesetter, though).  Either
requires a separate license.  AT&T was including DWB V1.0 "free" as
part of upgrades from UNIX System V Release 1 to UNIX System V
Release 2.0 until April 1984.

The combination of TITROFF & DWB includes support for the following
typesetters:
	C/A/T (needs work)
	Canon
	Imagen Imprint-10
	APS-5
	Mergenthaler Linotron-202
The font tables are stored external to TROFF and can be edited
without TROFF source (I am not sure how suitable a binary DWB
license is for this).  DITROFF output is ASCII and it is not too
hard to write a device filter IF you have the source for a good
one on hand to use as a guide.  The DWB device filters are, if
anything, excessively commented so one could hardly go wrong
working from one of those.

Apart from supporting a wider range of fonts and so forth, the
most notable functional addition to TROFF accomplished by DITROFF
is a set of graphic typesetter primitives, along with the "pic"
diagram preprocessor.