A group of special computer programs that help manage the computer's resources. It acts as an interface between application software, the hardware that makes up a computer system and the user of the system.
The OS controls the computer on the most fundamental level: it manages memory, controls access to peripheral devices and serves as a translator between the user and the hardware, providing the means for the user and application programs to tell the hardware what to do.
Operating systems include Mac OS X, MS-DOS, Microsoft Windows, Unix and Linux.
