The document discusses operating systems, including their definition, structure, features, types, advantages and disadvantages. It defines an operating system as software that manages computer hardware resources. Operating systems provide a user interface, coordinate tasks, establish internet connections and more. They have a kernel at the core and a user interface. Features include being graphical, supporting multiple users, tasks, processors and threads. Types include standalone, server and embedded operating systems. The best operating systems of 2013 are discussed as Ubuntu, Windows 8, Macintosh, Windows 7 and Linux Mint.