Operating Systems: A Structured Overview

Introduction:

Operating systems are core software programs that manage computer hardware resources and provide a platform for running applications. They act as intermediaries between users and hardware, translating user commands into instructions the hardware can understand.

Historical Context:

Before operating systems, humans interacted directly with computers, feeding them individual program instructions. This limited computers to running only one program at a time. The development of operating systems enabled users to submit batch jobs, allowing the OS to handle multiple programs sequentially.

Operating System Functions:

• Hardware Management: Controls and allocates hardware resources like memory, CPU, and I/O devices.
• Resource Sharing: Enables multiple applications to share hardware resources efficiently.
• Process Management: Creates, schedules, and terminates processes, ensuring smooth program execution.
• Memory Management: Allocates and manages memory space for applications and system processes.
• File Management: Organizes and provides access to data stored on storage devices.
• Security: Protects the system from unauthorized access and malicious activities.
• User Interface: Provides a platform for users to interact with the system and applications.

Types of Operating Systems:

• Batch: Processes jobs in batches without user intervention.
• Time-Sharing: Allows multiple users to share a single computer concurrently.
• Distributed: Runs on multiple interconnected computers, coordinating their activities.
• Network: Provides network services and communication facilities.
• Real-Time: Responds to events and controls processes within strict time constraints.
• Multiprogramming: Enables the execution of multiple programs simultaneously.
• Multitasking: Allows users to work on multiple tasks concurrently.

Kernel:

The kernel is the core component of an operating system, acting as the bridge between hardware and other software layers. It performs essential tasks like:

• Device Management: Communicates directly with hardware devices and translates user requests.
• Memory Management: Allocates and manages memory for different processes and system functions.
• Process Management: Schedules and controls the execution of processes.

Types of Kernels:

• Monolithic: Combines all operating system functionality into a single, large kernel. (e.g., Linux)
• Micro-kernel: Provides only essential services in the core and relies on user-space modules for additional functionality. (e.g., Mach)
• Hybrid: Combines elements of both monolithic and micro-kernel architectures. (e.g., Windows NT kernel)

Operating System Examples:

• Linux: Popular open-source OS for various platforms.
• Windows: Widely used commercial OS for personal computers.
• macOS: Apple's proprietary OS for Macintosh computers.
• Android: Mobile OS based on Linux, used in smartphones and tablets.
• iOS: Apple's mobile OS for iPhones and iPads.