Operating System (OS)

1. What is an Operating System?

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An Operating System (OS) is system software that manages computer hardware and software.
It acts as a bridge between the user and the computer.

2. Functions of Operating System

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  • Memory Management - Manges RAM allocation.
  • Process Management - Runs and controls programs.
  • File Management - Creates, deletes and organizes files.
  • Device Management - Controls keyboard, mouse, printer.
  • Security - Password & data protection.
  • User Interface - GUI or Command Line.

3. Types of Operating Systems

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  1. Batch OS - Worls on batches of jobs.
  2. Time-Sharing OS - Multiple users share CPU time.
  3. Distributed OS - Runs on multiple machines.
  4. Real-Time OS - Immediate response (defence, robots).
  5. Mobile OS - Android, iOS

4. Types of User Interfaces

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GUI (Graphical User Interface)
Commands typed manually
Example: Linux Terminal, CMD

5. Examples of Operating Systems

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  • Windows
  • Linux
  • macOS
  • Android
  • iOS

Which OS is open-source? → Linux

6. Booting Process

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Booting is the process of starting a computer.

Cold Booting
Starting computer from OFF state.
Warm Booting
Restarting a running computer.
BIOS
Basic Input Output System - stored in ROM.

7. File Systems

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  • NTFS - Windows
  • FAT32 - Pen drives
  • ext4 - Linux

8. Important Exam Points

  • OS is system software.
  • Linux is open-source.
  • GUI uses icons & windows.
  • CLI uses commands.
  • BIOS is stored in ROM.
  • Android OS is based on Linux.