Andrew Morton: Ext3 for Linux 2.4 Kernel: Provides links to documentation, patches, downloads, tools, CVS and mailing lists.
JFS for Linux: Provides specifications, documentation and downloads for IBM's journaled file system.
John's Spec of the Second Extended Filesystem (ext2fs): File structure compiled from resources published on the Internet, personal experience and Linux source code.
Simple Software Solutions: e_Fs: Provides description of features and links. Links include scenarios for use and list of efs function calls to replace standard C functions.