Mac OS X has been designed with three key isolation features: System Isolation, User Isolation, Memory and Application Isolation.  This guide is a brief overview of the article Key Isolation Features in Mac OS X at our main site and is specific to the Library Folders.
Three Different Library Folders
Mac OS X has three different Library folders located under the Macintosh HD:
  • /System/Library
  • /Library
  • /Users/<short name of user>/Library

/System/Library Folder

The /System/Library holds files that OS X needs to operate and function.  These are some files tied to the operation an inner workings of the Mac OS X operating system.  You shouldn't modify the contents of this folder.


/Library Folder

The /Library folder contains files available to ALL users and applications running on OS X.  These are shared and common files.  For example, fonts and printer settings.  This folder can be modified by the Administrative user.  This is the folder where third-party software and applications place the support files that they need to operate.


User Library Folders

The /Users/<short name of user> folder is user specific and holds files and settings as they relate to a user's  individual's preferences, recent items, web site bookmarks, Address Book entries, keychain, Widgets, and so on.





Note that unless you know what you're doing, do not alter the content in the Library folders.
 
Updates
  • July 13, 2008 - content revision and updated image for Leopard
Created: 12:49 PM on Dec 27, 2006
By: switchtoamac