An infrastructure software component of a computerized system. It controls all basic operations of the computer (or other electronic devices such as PDA, smartphone, etc.).
Among the most popular desktop operating systems are Windows, Mac OS, and variations of Linux, while the most widely used operating systems for mobile devices are Symbian and Windows Mobile.
Mobile devices with OS are called smartphones and can run full software applications (like games, organizer or communication applications) on top of the OS. Standardized operating system platforms make it possible to provide a consistent user interface (and experience) across devices from diverse hardware manufacturers.