A pictures of: Apple Mac OS X

The 'Cheetah', or Mac OS X version 10.0, was the first of Apple's big cat-themed versions of Mac OS X. Released in 2001, the new operating system marked a strong deviation from the Classic Mac OS with a completely new code base, changing the style of the desktop as well as the system of memory management. Although reviews were not quite as good as one would expect (users complained of missing features and issues with its performance) 'Cheetah' was noteworthy for its overall stability as an operating system. Unlike all later releases of Mac OS X, the cat code-name name was not used in promoting it.