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Operating System

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Operating System

An operating system is a collection of software program that controls the overall operation of the computer system. The Operating System manages the resources of a computer system manages the resources of  computer system and schedules its operation. The operating system acts as an interface between the hardware and the user level program and facilitates the execution of the program. 
 

Function of Operating System

1. File Management : Operating system handles the file organizations in the secondary storage devices. Operating system also provides certain services to the computer system in one form or the other. The operating system provides certain services to the users which can be listed in the following manner. 
  • Program Execution 
  • Error Detection and Handling
  • Manipulation of File System
  • Information and Resource Protection
  • Handling Input/Output Operations
  • Accounting
2. Security : The operating system uses password protection to protect user data and similar other techniques. It also prevents unauthorized access to programs and user data.

3. Resource Management : There are various other resources in computer system ( for example Printer). They must be distributed efficiently between the programs without any conflicts. For example, if Program "A" captures Hard disk and ask for Printer to print, and Program "B" captures printer and ask for Hard disk to write, then such condition creates "Deadlock" and system will be halted. Such conditions are avoided by Operating System and resource are avoided by Operating System and resource are efficiently distributed.

4. Job Scheduling : To increase the efficiency of processor, OS chooses various jobs scheduling mechanism which allocate certain time to each job. There is fast switching of processor time for each job waiting for processor time. Different algorithm like Round-Robin, Shortest Job First, First Come First serve are employed for this process. 

5. Memory Management : For any program to execute it must reside on the main memory. In a system where multiple programs are to be executed each program requires certain amount of memory. The memory management component of the operating system manages memory efficiently. As the demand for the multiple program execution increases more and more program are to be executed at the same time. So this requires a lot of memory and the available memory may not be enough for all programs that are under execution. In this case modern operation system uses secondary storage for nature. The virtual memory management are of two type
  • Paging
  • Segmentation
6. User Interface : The OS read the commands entered by the user interprets them and execute them by hardware. The command entry process is different in different user interface system. In UNIX system user interface system is provided through console (shell) and in Windows system the command entry is done by graphical elements like Menu, Toolbar, text boxes through the use of mouse and keyboard. 

7. Abnormal Program Termination :  When current executing program shows abnormal behaviors that may attempt to access the protected area of the system or tries to perform some malicious activities then the OS terminates the program immediately to prevent the system from failure. 

8. Event Logging : Operating System records all the events that happen in the computer system. It's very much useful for tracing the past records and troubleshoot (problem detection and correction) if something goes wrong. This is known as event log.


 

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