[4ad]

This is not from 2012, this is ancient. It talks about IL and 8½, which were removed more than 13 years ago.

[dang]

Ok, we'll take out the year until someone can suggest a plausible one. Though perhaps the author was working with obsolete info in 2012?

[smorrow]

It's "Notes on (the paper) 'Plan 9 From Bell Labs, 1995', 2012"

[rdc12]

The Barney Stinson homage, would put it at 2005 at the earliest (when the show started)

[4ad]

It's earlier than that, 4th edition was released in 2003, and IL and 8½ were removed between 3rd (2000) and 4th edition.