This version of Apple's OS also has a reduced footprint. This update does not have stacks of new features, rather overall improvements and efficiency upgrades. Mac OS X 10.6.8 Snow Leopard is an upgrade to the previous version of OS X Leopard. New features included Time Machine automated backup, Stacks, and Cover Flow. Where Mac OS X 10.4 Tiger had come in separate versions for PowerPC and Intel Macs, the Leopard installer could run on both platforms, and the version of Mac OS X installed could boot either type of hardware.
Leopard itself was also a unified operating system. For the first time, a version of OS X was certified as Unix, and the new unified appearance makes Leopard friendlier and less confusing for users. Mac OS X 10.5 Leopard, released on October 26, 2007, was the biggest change to Mac OS X since Apple first released OS X 10.0 in March 2001.
