OS X Mountain Lion (version 10.8) is the ninth major release of OS X (formerly Mac OS X), Apple Inc.'s desktop and server operating system forMacintosh computers. OS X Mountain Lion was released on July 25, 2012. It gains features from iOS, such as Notes and Reminders as applications separate from Mail and Calendar, in addition to those iOS features introduced in Mac OS X Lion. The latest update, rolled out on September 19, 2012, added some extra features such as Facebook integration.
OS X Mountain Lion replaces iChat with Messages, which includes support for iMessage, allowing users to send unlimited messages to other Macs(running 10.8 or later), iPhones, iPads and iPod Touches (running iOS 5 or later). It also includes the latest version of the Safari web browser, Safari 6. Another feature from iOS included in Mountain Lion is Notification Center, a sidebar pane that provides an overview of alerts from applications. It displays notifications until the user completes an associated action, rather than requiring instant resolution. OS X 10.8 also is well-integrated with iOS 6and is styled similarly.
OS X Mountain Lion received positive reviews, with critics praising Notification Center, Messages, and speed improvements over Mac OS X Lion, while criticizing Game Center for lack of games. Mountain Lion sold three million units in the first four days, making it Apple's most successful Mac OS