Introduction to Operating Systems

Study Notes

Introduction

A computer operating system (OS) is a software that manages computer hardware and software resources.
It acts as an intermediary between the user and the computer hardware.
It provides services like file management, process management, memory management, and device management.

Key Functions of Operating Systems

Process Management:
- Manages the execution of programs (processes) by allocating resources like CPU time and memory.
- Handles process creation, termination, scheduling, and synchronization.
- Implements mechanisms to prevent conflicts between concurrent processes.
Memory Management:
- Allocates and deallocates memory to programs.
- Manages virtual memory, which allows programs to use more memory than physically available.
- Handles paging and segmentation to improve memory utilization and efficiency.
File Management:
- Organizes and manages files and directories.
- Provides functionalities for creating, deleting, reading, writing, and manipulating files.
- Ensures access control and security of files.
Device Management:
- Controls and manages hardware devices (e.g., printers, keyboards, mice).
- Provides a standardized interface for interacting with these devices.
- Handles device drivers to facilitate communication between OS and hardware.
Security:
- Protects the system from unauthorized access and malicious software.
- Implements access control mechanisms, authentication methods (passwords, biometrics) to ensure secure operations of the OS.
User Interface:
- Provides a user-friendly way for users to interact with the system (e.g., command-line interface, graphical user interface).
- Allows users to execute commands, interact with files, and run applications.

Types of Operating Systems

Batch Operating Systems:
- Execute jobs in batches without direct user interaction.
Time-Sharing Operating Systems:
- Allow multiple users to share the system resources concurrently.
- Each user appears to have their own dedicated system.
Real-time Operating Systems (RTOS):
- Designed for applications requiring precise and predictable response times (e.g., industrial control systems, embedded systems).
- Provides guaranteed response times to critical events.

Common Operating Systems

Windows: Developed by Microsoft, primarily used for personal computers and desktops.
macOS: Developed by Apple, primarily used for Apple computers.
Linux: An open-source OS, widely used for servers, embedded systems, and desktops.
Android: A mobile operating system developed by Google.
iOS: A mobile operating system developed by Apple.

Key Concepts

Kernel: The core of the operating system.
- Manages system resources in real-time.
Shell: Provides a command-line interface for interacting with the kernel.
User Mode: Processes running with limited access.
Kernel Mode: Processes running with full access to system resources.

Modern Operating System Trends

Cloud computing: Operating systems are increasingly being designed to support cloud environments.
Virtualization: Enables running multiple operating systems on a single physical machine.
Mobile computing: Operating systems are optimized for mobile devices and their specific needs.
Security: Continued focus on protecting systems from threats and vulnerabilities.
Open-source movement: Continued growth in open-source operating systems like Linux and other distributions.

Description

This quiz covers the fundamental aspects of computer operating systems, including their key functions like process management, memory management, and file management. Users will learn how operating systems serve as intermediaries between hardware and software resources.