Booting a Computer: The operating system consists of a supervisor portion and a set of system programs. When the computer is switched on, the supervisor portion of the operating system (known as kernel) is loaded in the RAM from the disk. This process to start or restart a computer is called the booting process.

User interface: User interface means how the user interacts with the computer to perform various tasks. The user runs the application programs, opens the document, enters the data, and prints the output reports.

Running Programs: The operating system also provides the interface between the programs and the user. Through a program, the user accesses other computer resources such as printers, backing storage, or other application programs.

Managing Files: The data and programs are stored permanently on the disk for future use.

Memory Management: The memory unit has a very important role in data processing. The processor takes data and program instructions from RAM during processing. The data and programs are loaded from disk into RAM.

Scheduling Jobs: A job is an activity or operation that a processor performs. It may be receiving data from an input device, sending output to an output device or loading data from the disk into RAM.