The more proximal referent is Plan 9 from Bell Labs:

https://9p.io/plan9/

> Plan 9 from Bell Labs is a research system developed at Bell Labs starting in the late 1980s. Its original designers and authors were Ken Thompson, Rob Pike, Dave Presotto, and Phil Winterbottom. They were joined by many others as development continued throughout the 1990s to the present.

I've suspected; have no evidence to back this up, that "plan9" is a play on the roman numerals IX (9) at the end of "UN IX" and also that "research unix" never had a 9th or 10th version fully developed and released. And, TIL there's another thing called "IX"[1]

[1]https://www.cs.dartmouth.edu/~doug/IX/

Here's a funny thing I just found out: in chasing the reference cited by Wikipedia regarding the naming, I learned that UTF-8 was invented for Plan 9.

http://catb.org/~esr/writings/taoup/html/plan9.html

My understanding was it was a work in progress and they showed it to one of the plan 9 guys who pointed out a way to make it better and then implemented it into plan 9, not that it was particularly originally for plan 9.

There is a pretty complete description of the origination of UTF-8 here:

https://www.cl.cam.ac.uk/~mgk25/ucs/utf-8-history.txt

Rob Pike opens with:

> Looking around at some UTF-8 background, I see the same incorrect story being repeated over and over. The incorrect version is: 1. IBM designed UTF-8. 2. Plan 9 implemented it.

> That's not true. UTF-8 was designed, in front of my eyes, on a placemat in a New Jersey diner one night in September or so 1992.

ah, thanks for the source!

True, but that in turn was named after Ed Wood's Plan 9 from Outer Space. And its mascot "Glenda" is a reference to another of Wood's movies, Glen or Glenda.

That's not funny though, and it's an obvious reference to the movie.

> The name Plan 9 from Bell Labs is a reference to the Ed Wood 1957 cult science fiction Z-movie Plan 9 from Outer Space.[17] The system continues to be used and developed by operating system researchers and hobbyists.[18][19]

https://en.wikipedia.org/wiki/Plan_9_from_Bell_Labs

yes, but since you haven't nailed the humor yet, the original pointer-outer should have pointed out, "Plan 9 from Userspace is a follow-on to the Plan 9 operating system from Bell Labs, which was whimsically named after the film Plan 9 From Outer Space. Since the unix operating system is built on a simple security model of kernel-space and userspace, this clever word play is also informative about the architecture"

Having just watched it, I'll agree with the "so bad" part, but definitely not the "it's good" one.

Apparently plan 9 is specifically the space people's plan to resurrect the recently dead humans on Earth by shocking their pituitary glands.