All of the authoritative sources I've found say that it was started in the "late" 1980s, not "mid" 1980s. For instance: > Plan 9 from Bell Labs is a research

All of the authoritative sources I've found say that it was started in the "late" 1980s, not "mid" 1980s. For instance: > Plan 9 from Bell Labs is a research system developed at Bell Labs starting in the late 1980s. https://9p.io/plan9/about.html https://9p.io/plan9/about.html The Wikipedia's citation on the sentence saying "mid-1980s" is the press release for the 2nd edition of Plan 9 (1995, the first generally available version), which doesn't mention anything of the sort. That is to say: Wikipedia's "mid-1980s" claim isn't well-attributed. (The 1st edition of Plan 9 (1992) wasn't generally available, and was only made available to universities.) (My above 1987 citation states that they worked on it in 1987 and implies, but does not explicitly state, that there was no work before that.)