What is operating System
Operating System is a Master control program that runs the computer. In olden days lot of time used to be wasted in setting up computer and everything was supervised by an operator. Every time the computer is started, the operating system must be complied / assembled. Similarly, several application programs were required to be read into the CPU everyday. Thus lot of time was wasted in setting up the computer. This wastage of time can be avoided by maintaining all programs in storage devices. The required program can be recalled into CPU more quickly than in olden days.
Operating systems optimize the man-machine capabilities. Operating systems are based on the concept of modularity. Operating systems are also known as “executive systems” or “Control systems” or “monitor systems”.
Functions of an O/S
- Schedule jobs: An operating system can determine the sequence in which jobs are to be executed.
- Manage hardware and software resources: Operating system first loads the user’s application programs on to the computer’s primary memory and executes it. It makes various hardware units to perform as per the specifications of the application program.
- Maintain system security: To maintain security, operating system maintains a system of passwords in the organization. To enter into a system the user has to enter his password.
- Enable multiple user resource sharing: OS can handle the scheduling and execution of application programs for many users at the same time. This is called multi programming.
- Handle Interrupts: An interrupt is a technique used by the operating system to temporarily suspend the processing of one program in order to execute another program. Interrupts are issued when a program requests an operation or when the program exceeds some predetermined time limit.
- Maintain usage records: OS can record the amount of time used by each user for each system – the CPU, secondary storage, input and output devices.
