· http://developer.intel.com provides information about Intel processor architectures, including the x86 (IA32) architecture. If you are developing for x86 Linux and you use inline assembly instructions, the technical manuals available here will be very useful.
· http://www.amd.com/devconn/ provides similar information about AMD's line of microprocessors and its special features.
· http://freshmeat.net is an index of open source software, generally for GNU/Linux. This site is one of the best places to stay abreast of the newest releases of GNU/Linux software, from core system components to more obscure, specialized applications.
· http://www.linuxsecurity.com contains information, techniques, and links to software related to GNU/Linux security. The site is of interest to users, system administrators, and developers.