there was an x11 port to plan9. it's still there: $ cl -addr sources.cs.bell-labs.com:564 9p> ls -l extra/X11.iso.bz2 -rw-rw-r-- rsc sys 24878378

there was an x11 port to plan9. it's still there: $ cl -addr sources.cs.bell-labs.com:564 9p> ls -l extra/X11.iso.bz2 -rw-rw-r-- rsc sys 24878378 X11.iso.bz2 9p> that didn't sink plan9. what sank plan9 was that linux was there and was "good enough", and that it took a full decade to realize that the concepts of plan9 can't be backported to unix/linux piecemeal. that they fit much better together in a coherent system that didn't carry the baggage of unix (the root user, for example). this is what the original plan9 papers were trying to say: it's a rethinking, you have to cut the cord to eliminate the baggage. the baggage has proven sufficiently heavy that more than 20 years later you're not seeing private namespaces in linux. instead you see fully virtualized instances of the operating system -- with all the baggage that they carry -- and most efforts are focused on making them work efficiently, rather than on inventing something truly original. that said, if plan9 was open sourced in 1995 and had taken over, we wouldn't be talking now about a linux behemoth bolting systemd onto itself, but a plan9 one. successful software grows itself into morbidity. plan9 would've been no different.