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Introductions to Operating Systems

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This note is generated and a summarized version of the introduction.

Operating System Concepts - Notes

Overview

An Operating System (OS) is software that manages computer hardware and provides services for application programs. It acts as an intermediary between users and the hardware.

Key Functions of an OS:

  • Process Management
  • Memory Management
  • Storage Management
  • Protection and Security
  • User Interface

Types of Operating Systems:

  1. Batch OS – Executes jobs in batches without user interaction.
  2. Time-sharing OS – Allows multiple users to use the system simultaneously.
  3. Distributed OS – Manages multiple computers as a single system.
  4. Real-time OS (RTOS) – Provides real-time task execution for critical applications.
  5. Mobile OS – Designed for mobile devices (e.g., iOS, Android).

OS Components:

  • Kernel – Core part that manages hardware and system resources.
  • Shell – Interface for user interaction.
  • File System – Organizes and stores data.
  • Device Drivers – Interfaces between hardware and the OS.
  • System Utilities – Tools for system maintenance and optimization.

Process Management

A process is a program in execution. The OS is responsible for scheduling and managing processes efficiently.

Key Concepts:

  • Process States: New, Ready, Running, Waiting, Terminated.
  • Process Scheduling: Allocates CPU time to processes.
  • Interprocess Communication (IPC): Enables communication between processes.
  • Threads: Lightweight processes that share resources within a process.
  • Deadlock Handling: Prevents or resolves resource conflicts.

Memory Management

Memory management ensures efficient utilization of system memory.

Key Concepts:

  • Swapping: Moving processes between main memory and disk.
  • Paging: Dividing memory into fixed-size blocks.
  • Segmentation: Dividing memory into variable-sized segments.
  • Virtual Memory: Extends RAM using disk space.

Storage Management

The OS manages storage devices and file systems.

Key Concepts:

  • File System Structure: Organizes files in directories.
  • Disk Scheduling Algorithms: Optimize read/write operations.
  • RAID (Redundant Array of Independent Disks): Improves performance and reliability.

Protection and Security

The OS enforces security policies to protect data and resources.

Key Concepts:

  • Access Control: Restricts user permissions.
  • Encryption: Secures data transmission.
  • Authentication Methods: Passwords, biometrics, tokens.
  • Firewalls and Intrusion Detection Systems (IDS): Protect against attacks.

Advanced Topics

  • Virtual Machines: Run multiple OS instances on a single machine.
  • Distributed Systems: Enable resource sharing over networks.
  • Cloud Computing: Provides scalable, on-demand computing resources.
  • Mobile OS Considerations: Power efficiency, app sandboxing.

Case Studies

  • Linux: Open-source, widely used in servers.
  • Windows: User-friendly, dominant in desktops.
  • Mac OS: Unix-based, optimized for Apple devices.
  • Android & iOS: Leading mobile operating systems.

This document provides a concise overview of Operating System concepts. For detailed explanations, refer to specific chapters on each topic.

References

Information
  • date: 2025.01.23
  • time: 11:21

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