Apple - OS X Mountain Lion
Built on a rock-solid UNIX foundation, OS X is engineered to take full advantage of the technologies in every new Mac. And to deliver the most intuitive and integrated computer experience.
Hardware and software made for each other.
Since the software built into every Mac is created by the same company that makes the Mac, you get a fully integrated system in which everything works together perfectly. OS X works with the processor in your Mac to deliver the best possible performance. It works with the Multi-Touch trackpad in Mac notebooks so they feel natural to use. Power Nap takes advantage of the Mac hardware to keep the entire system up to date while it sleeps.1 And OS X gives you long battery life by working with the computerís built-in sensors to dim the screen in low-light conditions and even regulating processor activity between keystrokes.