seL4 has been open-sourced under GPLv2 and 2-clause BSD.
Linux iosnoop Latency Heat Maps, by Brendan Gregg.
SAILDART.net, “This archive presents the index to DART files recorded on tape at SAIL between November 1972 and August 1990.” Includes the original source of TeX.
redo in C++. A feature complete implementation by Jonathan de Boyne Pollard.
Computer Organization and Assembly Language Programming (1978), by James L. Peterson. Uses Knuth’s MIX architecture.
Steve Klabnik: Programming for Programmers, interviewed by Hanna Hurr. Fun read.
polyFORTH Reference Manual (PDF).
Google, Twitch, and the inexorable grind of capitalism, Charles Miller nails it: “It’s a deal that makes perfect sense for both parties, but the consumers lose.”