Operating Systems Basics

Definition and Functions

• An operating system (OS) is a software that manages computer hardware resources and provides common services to computer programs.
• OS acts as an intermediary between computer hardware and user-level applications.

Types of Operating Systems

• Single-User Single-Tasking OS: Allows one user to run one program at a time (e.g., MS-DOS).
• Single-User Multi-Tasking OS: Allows one user to run multiple programs simultaneously (e.g., Windows, macOS).
• Multi-User OS: Allows multiple users to access the computer simultaneously (e.g., Unix, Linux).

Key Components

• Kernel: The core of the OS that manages hardware resources and provides services to applications.
• Device Drivers: Software components that allow the OS to interact with hardware devices.
• System Libraries: Pre-built functions that applications can use to perform tasks.
• System Utilities: Programs that perform maintenance or management tasks (e.g., disk formatting, backups).

Operating System Layers

• Hardware Layer: The physical components of the computer (e.g., CPU, memory, storage).
• Kernel Layer: The OS kernel that manages hardware resources.
• System Library Layer: The system libraries that provide services to applications.
• Application Layer: The user-level applications that interact with the OS.

Operating System Functions

• Process Management: Creating, running, and managing processes (programs in execution).
• Memory Management: Allocating and managing memory for applications.
• File Management: Organizing, storing, and retrieving files.
• I/O Management: Managing input/output operations between devices and applications.
• Security: Protecting the system from unauthorized access and malicious activities.

Operating System Examples

• Windows: A popular, commercial OS developed by Microsoft.
• Linux: An open-source OS developed by Linus Torvalds.
• macOS: A proprietary OS developed by Apple for Mac computers.
• Unix: A multi-user, multi-tasking OS developed at Bell Labs.

Definition and Functions

• An operating system (OS) manages computer hardware resources and provides common services to computer programs.
• OS acts as an intermediary between computer hardware and user-level applications.

Types of Operating Systems

• Single-User Single-Tasking OS: allows one user to run one program at a time, e.g., MS-DOS.
• Single-User Multi-Tasking OS: allows one user to run multiple programs simultaneously, e.g., Windows, macOS.
• Multi-User OS: allows multiple users to access the computer simultaneously, e.g., Unix, Linux.

Key Components

• Kernel: manages hardware resources and provides services to applications.
• Device Drivers: software components that allow the OS to interact with hardware devices.
• System Libraries: pre-built functions that applications can use to perform tasks.
• System Utilities: programs that perform maintenance or management tasks, e.g., disk formatting, backups.

Operating System Layers

• Hardware Layer: physical components of the computer, e.g., CPU, memory, storage.
• Kernel Layer: OS kernel that manages hardware resources.
• System Library Layer: system libraries that provide services to applications.
• Application Layer: user-level applications that interact with the OS.

Operating System Functions

• Process Management: creates, runs, and manages processes (programs in execution).
• Memory Management: allocates and manages memory for applications.
• File Management: organizes, stores, and retrieves files.
• I/O Management: manages input/output operations between devices and applications.
• Security: protects the system from unauthorized access and malicious activities.

Operating System Examples

• Windows: a popular, commercial OS developed by Microsoft.
• Linux: an open-source OS developed by Linus Torvalds.
• macOS: a proprietary OS developed by Apple for Mac computers.
• Unix: a multi-user, multi-tasking OS developed at Bell Labs.