[svat]

Hmm interesting; I remember checking this for the time when TeX was written (1977, because of questions about building on top of troff) -- what I remember finding is that Unix wasn't widely available at colleges then. Perhaps things changed in the next 9 years. As far as I know, Knuth's access to computers at the time was still through Stanford's AI Lab (that's why the first version of TeX in 1977-1978 was written in SAIL; see also the comment for 14 Mar 1978 in http://texdoc.net/texmf-dist/doc/generic/knuth/errata/errorl...). Do you know if Unix was installed on Stanford lab computers by 1986? What was the distribution of these 100k Unix installations (academia/industry)?