What is operating system?

 Operating system

An operating system is a system software that controls the internal activity of the computer hardware and provides user interface. All application program need to be programed in such a way that they talk with the operating system for interacting and use hardware recourses.

Operating system that support a single user at a time is a single users operating system such as Window XP, Line X, Unix, etc.

Operating System can be classified into four category:

1. Single user operating system: Single user operating system allows to perform only one user to work on a computer at a time is known as single user operating system. Example: DOS, Windows, etc.
2. Multi user operating system: A multi user operating system allows a numbers of users to work together on a single computer. Each user will be provided a terminal connected to a single computer. Example: include Line x, Uni X, Window 2000, etc.
3. Single tasking operating system: A single tasking operating system which can exicute only a single task at a time is known as single tasking operating system. Example: DOS.
4. Multi tasking operating system: Multi tasking operating system supports execution's of more than one job at a time most of todays operating system such as Window 2000, Uni X, Line X, etc.

Functions of operating system

• Processor management: The operating system assign processor (if a computer has more than one processor) to the different task that must be performed by the computer.

• Memory management:  It operating system allocates the main memory and secondary memory to the system program, user program and data.

• Input/ Output management: It carries out the input/ output management and coordinates and assignment different input and output devices.

• File management: It manages files on various storage devices and the transfer of these files from one storage devices to another. It also allows all files to be easily changed and modified through the use of text editors or sum other use of text editors or sum other file menuplution software packages.

• Security management: It establish data security and integrity that is it keeps different programs and data in such a manner that they do not interfere with each other schedule.

• Scheduling management: Scheduling is the coordination of a computer's processing activity to optimize its utilization. This may be done by optimizing the number of instructions that are allowed to execute simultaneously or by scheduling instructions to execute at different times. The primary task of operating system scheduler is to make such scheduling decisions and this involves allocating processor time among competing software threads and tasks.