An operating system, such as Windows or Linux, is defined as the main program on a computer. It determines how the user performs tasks and how the interface appears. An interface example is your taskbar or desktop. An operating system, often referred to as an OS, also determines what software can be installed on a computer. For example, if a PC is running Linux, certain programs that run on Windows may not be compatible with this specific operating system.Some operating systems use a GUI, or a graphical user interface that presents information through pictures, such as buttons, dialog boxes, and icons.