What is an Operating System and explain its features?

OPERATING SYSTEM:-

An operating system is layer of software that acts as an interface between the computer hardware and user of the computer and it also controls the execution of application program. An operating system is system software i.e., a set of program which permits the continuous operation with the computer. 

Computer cannot work without an operating system, the job of an operating system is to control and co-ordinate the hardware parts within the C.P.U the operating system tells the computer what to do under every condition and exactly how to do it. 

FEATURES OF AN OPERATING SYSTEM:-

1. Program and data loading
2. Allocation of peripheral devices.
3. Interrupt handling 
4. Failure and recovery
5. Command interpretation 
6. File management 
7. Memory management 
8. Process management
9. Input / out put management 
10. Logging and accounting 
11. Security 

I) PROGRAM AND DATA LOADING

A computer program must be in machine understandable to be loaded. The operating system ensures that the data is also loaded and kept in the memory. The two areas i.e., program loading area and data loading area are different. 

II) ALLOCATION OF PERIPHERAL DEVICES:-

Allocation of computer resources such as memory to do various jobs, printer etc…….is done by the operating system. It manages hard disk storage CPU main memory and other peripheral devices. 

III) INTERRUPT HANDLING:- 

When the program ends whether normally or abnormally, the user is informed with an appropriate message and the storage used by the existing programs is released from the memory for the use of next program. This is accomplished by interrupt handler. Which will be taking care by operating system. 

IV) FAILURE AND RECOVERY:-

Since there is a transient danger of the computer stopping suddenly or unexpectedly. There may be change for disk crash,. Therefore a good operating system(OS) takes care of failure and recovery of the information. The operating system can periodically save the continuing of critical areas in some other storage areas (dump) incase of computer failure. The dump is used to recover and reconstruct the information from the last storage dump.

V) COMMAND INTERPRETATION:-

In order to run a task in a computer we have to give commands to it. O/S enable the computers to understand the command given by the user through keyboard or mouse. It also enable the computer to give the result based on the commands given by the user. 

VI) FILE MANAGEMENT :-

O/S provides data management facility such as data organization and retrieval from secondary storage device. O/S manage the files in the system. It enable the user to create, save, read, delete, copy and move the file from one place to another place. 

VII) MEMORY MANAGEMENT:-

The O/S allocates space for the files in the memory. The O/S only knows where particular files as being 

Kept in the memory when the user requires the file the O/S will search and given the file to the user. 

VIII) PROCESS MANAGEMENT:-

In a multi user O/S two or more processors can work at a time one computer for printing the document and so on. The O/S will do all works in an order and give sometime for each work. 

In multi user system, it selects new jobs for execution according to the priority. This is called time sharing or process management. 

IX) INPUT / OUT PUT MANAGEMENT:-

It manages the flow of data and instruction between the I/O devices and primary storage. It allocates and manages all I/O devices. It provides I/O instructions to start, printer, stop printer etc……

In order to run the program we need some values of input and output. The O/S not only provides the necessary values to all input and output parts but also controls them.

X) LOGGING AND ACCOUNTING :-

Logging is process of recording user interaction i.e all the O/S commands that are run by each and every user. The O/S keeps log of all logging users. It improves discipline in an organization. 

It also records which user is using the system and how much of processing time, main memory, the peripheral devices utilized etc……

XI) SECURITY:-

In order to product data the O/S allots a password to each and every user so that others cannot see or change the files of the user.