TrinityOS is a step-by-step, example-driven HOWTO on building a very functional Linux box with strong security in mind. TrinityOS is well known for its strong packet firewall ruleset, Chrooted and Split DNS (v9 and v8), secured Sendmail (8.x), Linux PPTP, Serial consoles and Reverse TELNET, DHCPd, SSHd, UPSes, system performance tuning, the automated TrinityOS-Security implementation scripts, and much more.
bpowerd is a daemon and makes proper use of the system log for error checking. It uses init's powerstatus calls to do it's dirty work, instead of calling shutdown itself. bpowerd is easy to compile and configure, using GNU's autoconf and providing explicit instructions for testing and installation. bpowerd was created using specs provided from the manufacturer, as opposed to reverse-engineering.