An operating system, or OS, is a system software that manages computer hardware and software resources, such as Windows, macOS, or Linux.

The OS manages files, memory, and processes as well as handles I/O operations.

The user and the operating system commonly communicate in the following steps:

  1. The user interacts with the program.
  2. The program interacts with the operating system.
  3. The operating system interacts with the hardware.

Then, the flow of communicate circles back to the user from hardware, to the operating system, to the program, to the user.