The non-Wintel user group, supporting Acorn, Amiga, Apple, ARM, Be, NCs, PowerPC, Psion, Unix and other alternative operating systems. Services include a non-Wintel news summary.
How Stuff Works: Operating Systems
Unbiased enlightening tutorial with impartial description of how OSs work, and many related links.
Internet Operating System Counter
Statistics on Internet OS use, WWW, FTP, and News servers. Over 940,000 hosts checked in this 1999 survey.
Growing article, with links to many related topics. Wikipedia.