A great resource for expanding your understanding of the way in which the system is put together can be found on the Web. Apple has extensive documentation about the design of Mac OS X available on the Apple Developer Connection (http://developer.apple.com/documentation/). A great place to start is the Mac OS X Technology Overview , which can be found at http://developer.apple.com/documentation/MacOSX/Conceptual/OSX_Technology_Overview/index.html.