Runoff from other systems begat Unix roff. Which begat new roff - aka nroff. both assume an ASR 37 as the output device. When the first typesetter was procured typesetter roff aka troff, was born which assumes the C/A/T as the output device (which is a binary format). This is also were typesetter C comes from. Note these are 3 separate and different programs although nroff and troff mostly take the same input language. These were included in V5/6/7 IIRC When newer typesetters were obtained and after the death of troff’s author, Brian rewrote the nroff/troff package to create ditroff- device independent typesetter roff which also could support ASCII output nroff style This version was released independently of the OS and took a separate license. Ditroff was reimplemented by Clark (IIRC) to create today’s groff which takes mostly a superset of the ditroff input language. Sent from my PDP-7 Running UNIX V0 expect things to be almost but not quite. > On May 14, 2018, at 8:41 AM, Dave Horsfall wrote: > >> On Mon, 14 May 2018, Doug McIlroy wrote: >> >> Here's part of the story. > > [...] > > You mentioned "nroff" a few times; would it not have been "troff" for their C/A/T photo-typesetter? At least, that was the lore that I heard... > > And what was "C/A/T" anyway (assuming that my memory is not failing me)? > > -- Dave