roff was a descendent of TYPESET and RUNOFF; both preceded Unix. https://en.wikipedia.org/wiki/TYPSET_and_RUNOFF https://en.wikipedia.org/wiki/TYPSET_and_RUNOF

roff was a descendent of TYPESET and RUNOFF; both preceded Unix. https://en.wikipedia.org/wiki/TYPSET_and_RUNOFF https://en.wikipedia.org/wiki/TYPSET_and_RUNOFF I would not be surprised if some version / implementation of roff ran on PDP-10 under some OS.