Unix and Linux

Mac Development Center has great articales on Mac OS X and Macs implimintation of Unix

The following table lists some of these folders that you'll see (Appendix A of Mac OS X for Unix Geeks contains a more comprehensive list)

File or Directory Description
.DS_Store This file contains Finder settings.
.Spotlight-V100 This file contains Spotlight settings.
.Trashes This directory contains files that have been dragged to the Trash.
.fseventsd Used by the File System events framework.
.hotfiles.btree This is used by Mac OS X's Hot-File-Adaptive-Clustering feature to keep track of frequently used files.
.vol/ This directory maps HFS+ file IDs to files.
Applications/ This directory holds all your Mac OS X applications. Check out its Utilities/ subdirectory for lots of fun stuff!
Developer/ Apple's Developer Tools and documentation. Only available if you have installed the Developer Tools.
Library/ Support files for locally installed applications, among other things.
Network/ Network-mounted Application, Library, and Users directories, as well as a Servers directory.
System/ Contains support files for the system and system applications, among other things.
TheVolumeSettingsFolder/ This directory keeps track of details such as open windows and desktop printers.
Users/ Home directories.
Volumes/ Contains all mounted filesystems.
.automount/ This directory handles static NFS mounts.
bin/ Contains essential system binaries.
cores/ If core dumps are enabled (with tcsh's limit and bash/sh's ulimit commands), they will be created in this directory as core.pid.
dev/ This directory contains files that represent various devices.
etc/ This directory contains system configuration files.
mach This is a symbolic link to the /mach.sym file.
mach.sym Kernel symbols.
mach_kernel The Darwin kernel.
private/ Contains the tmp, var, etc, and cores directories.
sbin/ Executables for system administration and configuration.
tmp/ Temporary files.
usr/ This directory contains BSD Unix applications and support files.
Desktop DB, Desktop DF The Classic Mac OS* desktop database.
Desktop Folder/ The Mac OS 9* desktop folder.
Shared Items/ Use by Mac OS 9* to share items between users.
System Folder/ The Mac OS 9* System Folder.
Temporary Items/ Temporary files used by Mac OS 9*.
Trash/ Mac OS 9* trash folder
VM Storage Mac OS 9* virtual memory file.
* OS 9 is DEAD!