An Operating system is a program that controls the execution of application programs and acts as an interface between the user of a computer and the computer hardware.
Need of an operating system:
When a program written in a high level language is executed by a computer, the following steps are followed…
The compiler to translate the program is loaded in the memory.
The source program is read and loaded in the memory.
The source program is compiled into object program, while compiling if any syntax errors are detected in the program, appropriate messages are displayed or printed.
Linking and loading process.
The input-output commands for different devices should include monitoring their status and detecting errors. These are programmed by experts with great care.
In earlier day’s user had to design the application according to the internal structure of the hardware. Operating System was needed to enable the user to design the application without concerning the details of the computer’s internal structure. In general the boundary between the hardware & software is transparent to the user.
Usage of Operating System:
1. Easy interaction between the human & computer.
2. Starting computer operation automatically when power is turned on.
3. Loading & scheduling users program.
4. Controlling input & output.
5. Controlling program execution.
6. Managing use of main memory.
7. Providing security to users program.
Functions of Operating System:
The main functions perform by most Operating System of today are as follow: -
1. Process Management: - The process management module of an Operating System takes care of the creation & deletion of processes, scheduling of various system resources to the different process requesting them, & providing mechanism for synchronization & communication among processes.
2. Memory Management: - The memory management module of an Operating System takes care of the allocation & reallocation of memory space to