At 2022-06-06T11:40:42+1000, Warren Toomey via TUHS wrote:
> Hi all, we have a new addition to the Unix Archive at:
> https://www.tuhs.org/Archive/Documentation/Manuals/Unix_4.0/
> 
> This is the documentation for Unix 4.0 which preceded System V. The
> documents were provided by Arnold Robbins and scanned in by Matt
> Gilmore.

Thank you all very much for this.  As an amateur *roff historian I think
among the other treasures here is a January 1981 addendum to Ossanna's
1976 Nroff/Troff User's Manual.  This would be _after_ Kernighan's
rewrite of the code to become device-independent troff.  Indeed, the
only troff (cf. nroff) device documented as supported is "Wang
Laboratories' C/A/T phototypesetter".  Not the Linotron, not the
Autologic, not the Imagen.

This is the earliest attestation of device-independent troff I'm aware
of, and moreover it's _documentary of the system_.  Great stuff!

(I've effused about this on the groff list already.)

Regards,
Branden