Operating system
![Operating system placement.svg](/Images/godic/202502/10/Operating_system_placement.svg0153.png")
![OS/360 was used on most IBM mainframe computers beginning in 1966, including computers used by the Apollo program.](/Images/godic/202502/10/IBM360-65-1.corestore0153.jpg")
![PC DOS was an early personal computer OS that featured a command line interface.](/Images/godic/202502/10/PC_DOS_1.10_screenshot0153.png")
![Mac OS by Apple Computer became the first widespread OS to feature a graphical user interface. Many of its features such as windows and icons would later become commonplace in GUIs.](/Images/godic/202502/10/Apple_Macintosh_Desktop0154.png")
An operating system (OS) is system software that manages computer hardware and software resources and provides common services for computer programs. The operating system is a component of the system software in a computer system. Application programs usually require an operating system to function.