The operating system provides an interface between the user and the hardware. The operating system acts as a medium between the hardware and user so that the user does not have to see exactly what is going on inside the computer or understand the complexity of its operations.

The operating system enables software developed by third parties to run on different type of computer systems running the operating system, using the same user interface known as Application user interface (API).

The operating system serves as a resource manager. The Os allocates resources such as memory to programs, for instance in the case of multitasking, the OS controls how much memory is allocated to each program. Other resources that are managed by the OS are the processor, disk space, hardware devices and connection to other systems.

The operating system makes it possible for the user to run more than one program at a time. This is referred to as multitasking.

The operating system makes it possible for more than one user to use a system at the same time. This is known as a multi user operating system.

The operating system manages the security of the computer system. This includes the user access to the computer, authentication and user control.

The operating system also manages peripherals devices attached to the system. For example the operating system manages how data is sent to the printer.

The operating system also manages the data flow from disk to application and it also communicate with the user by displaying messages about specific actions taken or sending warnings to the user in case of errors.