David Laight writes:

>> (A predecessor to troff was actually one of the first applications
>> Unix was used for.)
>
>Didn't need Unix - runoff (I think it was) ran on the pdp11/40 under
>RSX11/M (and probably somewhat faster under RT11)

Yes, the runoff stuff seems to not have been invented on Unix but
according to history, the first non-developper users of Unix have
been the patent office at Bell Labs, typing documents with ed and
formatting them with roff (and some people today say that text
processing is a rather foreign thing to Unix...:)

--mkb