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OPERATING SYSTEM

1. FUNDAMENTALS OF OPERATING SYSTEM

1. Definition of an Operating System (OS):

An operating system is a software that acts as an intermediary between computer hardware and the user. It provides a user-friendly interface to interact with the computer, manages hardware resources, and enables the execution of applications.

2. Concepts of Operating System:

Key concepts include:

  • Process Management: Handling the execution of processes, including multitasking and scheduling.
  • Memory Management: Managing the computer’s memory, including allocation and deallocation of memory space.
  • File System Management: Organizing and managing data storage on disks.
  • I/O System Management: Managing input and output devices and operations.
  • Security and Protection: Ensuring system security and data integrity by controlling access to system resources.
  • Networking: Managing data transmission between devices over networks.

3. Evolution of Operating Systems:

The evolution of operating systems can be traced through several stages:

  • Early Systems: Computers had no operating systems; users interacted with hardware directly via machine language.
  • Batch Processing: In the 1950s, batch processing was introduced where tasks were queued and processed one after the other.
  • Multiprogramming: Introduced in the 1960s, it allowed multiple programs to be loaded into memory and executed concurrently.
  • Time-Sharing: Allowed multiple users to share the system's resources simultaneously by dividing time among them (1960s–1970s).
  • Personal Computers: In the late 1970s and 1980s, OS like MS-DOS and early versions of Windows for PCs emerged.
  • Graphical User Interfaces (GUI): GUIs made operating systems more user-friendly (e.g., Windows, macOS).
  • Modern OS: These offer multitasking, security, virtualization, and robust networking (e.g., Linux, Windows 10/11).

4. Operating System Terminologies:

  • Kernel: The core part of the OS responsible for managing system resources.
  • Process: An instance of a program in execution.
  • Thread: A smaller unit of process execution.
  • Multitasking: The ability to run multiple tasks (processes) simultaneously.
  • Virtual Memory: A memory management technique that uses disk space to extend physical memory.
  • Shell: A user interface to access the OS services (e.g., command-line interfaces).

5. Operating System Structures:

  • Monolithic Architecture: All OS services run in the kernel space.
  • Layered Structure: Divides the OS into layers where each layer has specific functionalities.
  • Microkernel Architecture: The kernel provides minimal services like communication, while other services run in user space.
  • Modular Architecture: Combines aspects of both microkernel and monolithic systems, allowing dynamic loading of modules.

6. Types of Operating Systems:

  • Batch Operating System: Processes tasks in batches without user interaction.
  • Time-Sharing Operating System: Allows multiple users to share system resources simultaneously.
  • Distributed Operating System: Manages a group of independent computers and makes them appear as a single system.
  • Real-Time Operating System (RTOS): Designed for real-time applications that need to process data without delay.
  • Network Operating System (NOS): Provides services to computers connected to a network.
  • Mobile Operating System: Designed specifically for mobile devices (e.g., Android, iOS).

7. Functions of Operating Systems:

  • Process Management: Creating, scheduling, and terminating processes.
  • Memory Management: Keeping track of memory allocation and optimizing memory use.
  • File Management: Creating, organizing, and managing files and directories.
  • Device Management: Handling input/output operations and managing connected devices.
  • Security Management: Ensuring data security through authentication, access control, and protection mechanisms.
  • Error Detection: Identifying and resolving system errors.
  • User Interface: Providing a graphical or command-line interface for user interaction.

8. Operating System Installation:

  • Planning: Ensure the hardware meets the system requirements for the OS.
  • Backing Up Data: Backup important data before proceeding.
  • Installation Media: Use installation media such as a USB drive, CD/DVD, or ISO file.
  • Installation Process: Follow installation instructions from the installation media, which typically involves formatting the disk, setting up partitions, and installing the OS files.
  • Post-Installation: Install drivers, set up user accounts, and configure system settings as needed