[mdrzn]

"The Plan 9 CD-ROM needed about 100MB for the full distribution, if that."

I have no idea what they are talking about, what Plan 9 is, what is being distributed, why is AT&T involved, etc. Read the whole first post, still have no clue.

[dredmorbius]

Here's a handy guide to uncovering such information for yourself, and being able to write a TIL rather than an IHNFC:

TUHS is The Unix Heritage Society mailing list, which might offer you some cues as to context. There's a link at the top-right of the submitted link:

https://www.tuhs.org/mailman3/hyperkitty/list/[e-mail]/

Rob Pike is Kind of A Big Deal in Unix, C (he's the Pike in Kernighan and Pike, a/k/a The UNIX Programming Environment (https://en.wikipedia.org/wiki/The_Unix_Programming_Environme...)) The Go programming language, and a thing called Plan 9.

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

Plan 9 From Outer Space was a so utterly bad it's ... well, just bad ... 1957 science fiction film.

https://en.wikipedia.org/wiki/Plan_9_from_Outer_Space

Plan 9 from Bell Labs appropriated the name from the film for an operating system building on Pike's (and others') earlier experience developing Unix.

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

You can download and install Plan 9 OS if you like: https://plan9.io/plan9/

Ten Thousand: https://xkcd.com/1053/