Question
What are the purpose of operating system and its functions?

Answer:
An operating system is the most important software that runs on a computer. It manages the computer's memory and processes, as well as all of its software and hardware. It also allows you to communicate with the computer without knowing how to speak the computer's language.
An operating system has three main functions: (1) manage the computer's resources, such as the central processing unit, memory, disk drives, and printers，(2) establish a user interface and (3) execute and provide services for applications software.