what purpose does operating system serve to the computer and the user
Operating system An operating system (OS) is system software that manages computer hardware and software resources and provides common services for computer programs. All computer programs, excluding firmware, require an operating system to function.
Single user mode Unix-like operating systems provide single user mode functionality either through the System V-style runlevels, BSD-style boot-loader options, or other boot-time options.
Computer data storage Data are encoded by assigning a bit pattern to each character, digit, or multimedia object. Many standards exist for encoding (e.g., character encodings like ASCII, image encodings like JPEG, video encodings like MPEG-4).
Denial-of-service attack A wide array of programs are used to launch DoS-attacks.