Linux

http://www.quora.com/Linux/How-many-lines-of-code-if-any-from-Linux-1-0-are-still-in-the-modern-Linux-kernel-and-what-is-it There are more than a few lines of code from Linux 1.0 and even 0.01 in the modern kernel.

http://lwn.net/Articles/528935/ Al Viro on how signals are handled during syscalls in Linux.

http://static.debian-handbook.info/browse/stable/ The Debian Administrator's Handbook is an ebook now available for free on the web.

Yesterday's Gil's LotD was caught by Google's spam filter. If you didn't get an email you can always read it on the website.

http://www.ibiblio.org/oswg/oswg-nightly/oswg/en_US.ISO_8859-1/articles/alan-cox/mac/mac.html Alan Cox on porting Linux to 68k Macintoshes.

http://mjg59.livejournal.com/136274.html A rant on the desire to create "lightweight" open source software replacements. I'm linking this in particular because "To a first approximation, when someone says "Lightweight" what they mean is 'I don't understand the problems that the alternative solves'." is an excellent quote and summary of the issue.

http://devstructure.com/ Blueprint figures out your server's configuration so you can reproduce it later.

http://codemonkey.org.uk/2011/06/01/red-star-kernel/ North Korea has released its own Linux distribution. I'd love to see the source.

http://checkinstall.izto.org/ CheckInstall wraps up standard GNU makefiles and creates packages for various package managers.

http://www.mnxsolutions.com/security/two-factor-ssh-with-google-authenticator.html Google's new two-factor authentication can be hooked into PAM.

http://www.scribd.com/doc/3501952/GNUs-Not-Eunuchs esr and rms slash.