Mac OS X Snow Leopard

Mac OS X Snow Leopard (10.6.x) is an operating system developed by Apple and the seventh major release of Mac OS X. Snow Leopard is one of Apple's longest lasting Mac OS X operating systems with five years of support and launched with largely positive reviews.

Differences from Leopard

 * This version removed support for the PPC architecture due to Apple's intent to support Intel processors.
 * It is also the last version to use Rosetta, and thus the last version to run PPC-only applications.
 * It's Finder has become completely rewritten in Cocoa to use the advantages of Mac OS X. Before that, Finder was based on the Carbon API.
 * Version 10.6.6 introduced the Mac App Store, an ESD marketplace for free and paid programs for Mac OS X.