Question

What are the main functions of an operating system?​

Answer 1

Explanation:

An operating system has 3 main functions :

1) manage the computer's resources, such as the central processing unit, memory, disk drives, and printers, 2) establish a users interface, and 3) execute and

provide services for applications software.

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Answer 2

Functions of an Operating System

I) Process management:

• Operating System do the management of CPU.
• OS takes case of the allotment of CPU to different processor.
• When CPU is free, The OS detects a process from Job Queue and allocates the CPU to the process.
• When process execution will get completed, OS frees the process and again selects another process for execution.
• Selection of process form Job Queue is done by using various CPU scheduling techniques like FCFS, SJF, Priority & Round Robin.
• In process management function, OS assigns the processor to a process & deallocate processor when it is not required.

II) File management function:

• File: A file is a logical related collection of information.
• File is stored in secondary storage like Magnetic disk, Optical disk, etc.
• A file may contain a report, an executable program or a set of commands to the OS.
• OS manages the files, folders & directory systems on a computer.

An Operating System does the following activities for file management:

• Creating and deleting files
• Creating and deleting directories
• OS keeps information of files using File Allocation Table (FAT)
• FAT stores general information about files like filename, type (text or binary), size, access mode (sequential, indexed sequential, direct, relative)
• OS takes care that files are opened with proper access rights (Read or R/W)
• Backup files on stable storage media.
• File management of OS helps to create, edit, copy, allocate memory to the files & also updates the FAT.

III) Memory Management Function:

• Memory is the large array of words or bytes, each with its own address.
• Main memory is directly accessed by CPU.
• For a program to be executed it must be in the main memory.

An OS does the following activities for Memory management

• Keeps track of primary memory using free space management (which partition is free and which is free)
• Allocates the memory to process when it requests it.
• Deallocates the memory when a process terminated & the same memory area is allocated to another process.

IV) I/O device management function:

• OS manages I/O & makes the I/O process effective.
• OS accepts the input from the input device (keyboard) stores it in main memory,ask the CPU to process it & finally provides the result to the output device (screen/printer) for output.
• OS controls all I/O devices attached to computer with the help of small software called device drivers.
• OS keeps track of all devices with the help of I/O controller.
• OS decides which process gets the device when & for how much time.
• Allocate & Deallocate devices in the efficient way.

V) Security Management:

• There are various viruses, threats which can interfere with the normal operation of computer and can be very harmful & results in loss of data or system crashes.
• OS of a computer has a number of built-in tools to protect against security threats, including the use of viruses scanning utilities & setting up a firewall to block suspicious network activities.