Is plan9 sufficiently unix to be on-topic here?
(I suppose it might not not really be a question of sufficiency; perhaps plan9 is too unix for this site?)
plan9's design is hard-core UNIX philosophy, and I'd be happy to see a few questions here. I can't imagine we'll be overwhelmed.
Although Plan9 and Unix are connected both history-wise and technology-wise, I don't think it really rates as a unix system. Then again modern unices have acquired features inspired from Plan9 (UTF-8,
While I'm sympathetic to the wish to have a good place to discuss “alternative” operating systems, I don't want Unix.SE to be about all-but-Windows. This is primarily a political concern: I don't want to spread the idea that Windows is the normal operating system, and everything else is lumped together under as “alternative”, only-for-nerds, not-serious...
So if Plan9 is to be considered on topic (count me as mildly against), we need to draw a line somewhere (of course getting into the what's-a-unix debate). What about Hurd? Multics? ITS? QNX? VMS? CP/M? OS/2? Windows?