Additional Resources | Official Red Hat Linux Administrators Guide

Following are additional sources of information about /proc/.

Most of the best /proc/ documentation is available on your system.

/usr/src/linux-2.4/Documentation/file systems/proc.txt — Contains assorted, but limited, information about all aspects of the /proc/ directory.
/usr/src/linux-2.4/Documentation/sysrq.txt — An overview of System Request Key options.
/usr/src/linux-2.4/Documentation/sysctl — A directory containing a variety of sysctl tips, including modifying values that concern the kernel (kernel.txt), accessing file systems (fs.txt), and virtual memory use (vm.txt).
/usr/src/linux-2.4/Documentation/networking/ip-sysctl.txt — A look at various IP networking options.
/usr/src/linux-2.4 — Some of the most authoritative information on /proc/ can be found by reading the kernel source code. Make sure the kernel-source RPM is installed on your system and look in the /usr/src/linux-2.4 directory for the source code.

http://www.linuxhq.com — This site maintain a complete database of source, patches, and documentation for various versions of the Linux kernel.