1. INTRODUCTION TO OPERATING SYSTEM

An Operating System (OS) is a fundamental software that acts as an interface between the user and the computer hardware. It manages all hardware and software resources, enabling users and applications to interact with the computer system efficiently.

Definition

An Operating System is system software that manages computer hardware, software resources, and provides common services for computer programs.

Functions of an Operating System

The primary functions of an operating system include:

  1. Process Management
    It handles the creation, scheduling, and termination of processes. The OS ensures smooth execution by managing process states and priorities.

  2. Memory Management
    It manages the allocation and deallocation of memory space to different programs and users to ensure efficient memory use.

  3. File System Management
    The OS controls the reading, writing, creation, and deletion of files and directories. It also manages file permissions and storage.

  4. Device Management
    It manages hardware devices through drivers, ensuring smooth communication between hardware and software.

  5. Security and Access Control
    The OS protects data and system resources through user authentication, permissions, and encryption.

  6. User Interface
    Provides a user-friendly interface—either Command Line Interface (CLI) or Graphical User Interface (GUI)—for interacting with the system.

Types of Operating Systems

  1. Batch Operating System
    Executes batches of jobs with minimal user interaction.

  2. Time-Sharing Operating System
    Allows multiple users to use the system simultaneously by sharing time slots.

  3. Distributed Operating System
    Manages a group of independent computers and makes them appear as a single system.

  4. Real-Time Operating System (RTOS)
    Used in systems that require immediate processing and response, such as medical systems or embedded devices.

  5. Network Operating System
    Supports networking functions like file sharing and communication between computers.

  6. Mobile Operating System
    Specialized OS designed for mobile devices, e.g., Android and iOS.

Examples of Operating Systems

  • Microsoft Windows

  • macOS

  • Linux

  • UNIX

  • Android

  • iOS