Linux

lwn.net An excellent source of technical articles on Linux

The Linux Scheduler

V4L2 Linux video driver writer's guide

Smallest possible ELF executable - Original at A Whirlwind Tutorial on Creating Really Teensy ELF Executables for Linux

Linux memory management

SystemTap

https://0xax.gitbooks.io/linux-insides/content/index.html

Admin

http://www.ipsure.com/blog/2011/postfix-virtual-setup-dovecot-spamassassin-clamav-maia-roundcube-w-mysql-db-on-freebsd/

http://www.allaboutspam.com/email-server-test/

http://greylisting.org/test/

!linux

I found this blog (Linux Hater's (sic)) while searching for a link to Ulrich Drepper's papers. It has some entertaining gripes.