It is the Unix based Operating system by Apple Inc. It was launched as OS X Cheetah, back in 2001. and presently its latest version is names ad El Captain. Apple described this release as containing "Refinements to the Mac Experience" and "Improvements to System Performance" rather than new features. Refinements include public transport built into the Maps application, GUI improvements to the Notes application, adopting San Francisco as the system font, and the introduction of System Integrity Protection. It is easy to use and supports multiple gestures to use. It also has wide numbers Apps in the app store. Overall its a best OS yet made by Apple.