Alternative OSs on the Net  
   Huge, comprehensive, alphabetized list of operating systems and OS link sites. All links, no comments.
   http://www.d1.dion.ne.jp/~r_high/GeekOS/indexos.html

A Catalog of Operating Systems  
   Classified, alphabetic listing of most operating systems, past and present, distributed commercially or reported in English-language literature, platform oriented. From Computer Science 258, West Virginia University.
   http://www.csee.wvu.edu/~jdm/classes/cs258/OScat

Entries Relating to Operating System  
   Alphabetized list of some 500 links to entries that relate to OSs, from FOLDOC (Free Online Dictionary of Computing) at the University of Brighton, BURKS project.
   http://burks.brighton.ac.uk/burks/foldoc/subjects/6.htm

Linux Kernel Architecture and Other OS Links  
   Categorized, large link list of resources on several operating systems: Linux, Windows, BSD, Mac OS X, Unix, Solaris, Palm OS, Symbian, Stinger (SmartPhone), general.
   http://cs.uml.edu/~cgould/

Microcomputer Operating Systems  
   Some 70 OSs that run on microcomputers, PCs. User interfaces in earlier systems are command-line, character-oriented; later systems are mostly GUI-based. List, with brief descriptions, no links. From West Virginia University.
   http://www.csee.wvu.edu/~jdm/classes/cs258/OScat/micros.html

The OS Center: All About OSs  
   Alphabetized descriptions and links on many operating systems, related issues, research groups, organizations.
   http://www.icselectionguide.com/

OS Projects  
   Alphabetized list, links to many projects.
   http://www.osdev.org/cgi-bin/projects.cgi

Paul Hsieh OS Page  
   Loosely categorized list of about 100 links to developer resources for creating OSs, emulators, alternative OSs.
   http://www.azillionmonkeys.com/qed/os.html

Operating Systems  
   Links to tutorials, tips, free online how-to guides for BeOS, DOS, Macintosh; POSIX, Unix, Linux; OS/2, Windows 3.x-95/98/Me-NT/2000/XP-CE, mixed. [Knowledge Hound how-to directory]
   http://www.knowledgehound.com/topics/OSs.htm

Just Say No to Microsoft: Operating Systems  
   Describes dozens of living OSs, grouped by family similarities. Most are alternatives to Microsoft.
   http://microsoft.toddverbeek.com/os.html

Open Source Ring  
   Alphabetized list of many links, OSs, projects.
   http://www.webring.com/hub?ring=os