Introduction of Operating System

An operating system acts as an intermediary between the user of a computer and computer hardware. The purpose of an operating system is to provide an environment in which a user can execute programs in a convenient and efficient manner.

An operating system is software that manages the computer hardware. The hardware must provide appropriate mechanisms to ensure the correct operation of the computer system and to prevent user programs from interfering with the proper operation of the system.

Operating System – Definition:

§  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.

§  A more common definition is that the operating system is the one program running at all times on the computer (usually called the kernel), with all else being application programs.

§  An operating system is concerned with the allocation of resources and services, such as memory, processors, devices and information. The operating system correspondingly includes programs to manage these resources, such as a traffic controller, a scheduler, memory management module, I/O programs, and a file system.

Functions of Operating system – Operating system performs three functions:

1.      Convenience: An OS makes a computer more convenient to use.

2.      Efficiency: An OS allows the computer system resources to be used in an efficient manner.

3.      Ability to Evolve: An OS should be constructed in such a way as to permit the effective development, testing and introduction of new system functions without at the same time interfering with service.

Operating system as User Interface –

User

1.      System and application programs

2.      Operating system

3.      Hardware

Every general purpose computer consists of the hardware, operating system, system programs, and application programs. The hardware consists of memory, CPU, ALU, and I/O devices, peripheral device and storage device. System program consists of compilers, loaders, editors, OS etc. The application program consists of business programs, database programs.

Every computer must have an operating system to run other programs. The operating system coordinates the use of the hardware among the various system programs and application programs for a various users. It simply provides an environment within which other programs can do useful work.

The operating system is a set of special programs that run on a computer system that allows it to work properly. It performs basic tasks such as recognizing input from the keyboard, keeping track of files and directories on the disk, sending output to the display screen and controlling peripheral devices.
OS is designed to serve two basic purposes:

1.      It controls the allocation and use of the computing System’s resources among the various user and tasks.

2.      It provides an interface between the computer hardware and the programmer that simplifies and makes feasible for coding, creation, debugging of application programs.

The Operating system must support the following tasks. The task are:

1.      Provides the facilities to create, modification of programs and data files using and editor.

2.      Access to the compiler for translating the user program from high level language to machine language.

3.      Provide a loader program to move the compiled program code to the computer’s memory for execution.

4.      Provide routines that handle the details of I/O programming.