Which of following options is not a function of operating system.

The correct answer is Database management.

Key Points

• An operating system is a program on which application programs are executed and acts as a communication bridge (interface) between the user and the computer hardware. 
• The main task an operating system carries out is the allocation of resources and services, such as the allocation of memory, devices, processors, and information.
• The operating system also includes programs to manage these resources, such as a traffic controller, a scheduler, a memory management module, I/O programs, and a file system. 

Additional Information

• Memory Management 
  • The operating system manages the Primary Memory or Main Memory.
  • Main memory is made up of a large array of bytes or words where each byte or word is assigned a certain address.
  • Main memory is fast storage and it can be accessed directly by the CPU. For a program to be executed, it should be first loaded in the main memory.
• Processor Management 
  • In a multiprogramming environment, the OS decides the order in which processes have access to the processor, and how much processing time each process has.
  • This function of OS is called process scheduling.
• File Management 
  • A file system is organized into directories for efficient or easy navigation and usage. These directories may contain other directories and other files.
• Database management system (DBMS)
  • It is a software package designed to define, manipulate, retrieve and manage data in a database.
  • A DBMS generally manipulates the data itself, the data format, field names, record structure, and file structure.
  • It also defines rules to validate and manipulate this data.