Mac OS X Snow Leopard (version 10.6) is the seventh major release of Mac OS X, Apple's desktop and server operating system for Macintosh computers.
The release of Snow Leopard came nearly two years after the introduction of Mac OS X Leopard, the second longest time span between successive Mac OS X releases (the time span between Tiger and Leopard was the longest).
Unlike those of previous versions of Mac OS X, the goals of Snow Leopard were improved performance, greater efficiency and the reduction of its overall memory footprint.
Addition of new end-user features was not a primary consideration: its name signified its goal to be a refinement of the previous OS X version, Leopard.
Much of the software in Mac OS X was extensively rewritten for this release in order to take advantage fully of modern Macintosh hardware.
New programming frameworks, such as Open CL, were created, allowing software developers to use graphics cards in their applications.
This is also the first Mac OS release since System 7.1.1 that does not support Macs using Power PC processors, as Apple now intends to focus on its current line of Intel-based products.
As support for Rosetta was dropped in OS X Lion, Snow Leopard is the last version of Mac OS X that is able to run Power PC-only applications.
Snow Leopard was succeeded by Mac OS X Lion (version 10.7) on July 20, 2011.
Since then, Apple has continued to sell Snow Leopard from its online store for the benefit of users that require Snow Leopard in order to upgrade to later versions of OS X, which have all been distributed through the Mac App Store introduced in the Snow Leopard 10.6.6 update.