An Operating System (OS) is an interface between a computer user and computer hardware. It is a software, which performs many operations such as controlling and coordinating the use of the hardware among the various application programs for various users. It manages both the hardware and software resources of the system. At a low level, it is a set of programs that manages devices and lets other programs interface with the hardware. At a high level, it's a system that allows users to run applications, manage files, and perform networking functions.