Components

Six main components of Linux operating system

Components of Linux Operating System

The main components of Linux operating system are: Application, Shell, Kernel, Hardware, Utilities.

1. Hardware Layer

This is the bottom-most layer of the Linux architecture, consisting of physical components such as CPU, Memory (RAM), Hard disks and SSDs,Input/output devices (keyboard, mouse, etc.),Networking hardware (Ethernet, Wi-Fi cards).

The hardware layer interacts directly with the Linux kernel through device drivers.

2. Kernel

The kernel is the core of the Linux operating system. It acts as a bridge between the hardware and software layers. The kernel manages system resources and facilitates communication between hardware and software.

Functions of the Kernel:

• Process Management: Handles process creation, scheduling, and termination.

• Memory Management: Allocates and manages memory (RAM) for processes.

• Device Drivers: Interfaces with hardware devices (e.g., disk drives, network interfaces).

• File System Management: Manages file operations and storage systems.

• System Calls: Provides an interface for applications to request kernel services.

Types of Kernels:

• Monolithic Kernel: Used in Linux; all functionalities (e.g., drivers, file systems) are included in a single kernel binary.

• Microkernel: Opposite of monolithic, used in some other operating systems.

3. Shell

The shell is the command-line interpreter (CLI) that provides a user interface to interact with the kernel. It interprets user commands and passes them to the kernel for execution.

Types of Shells in Linux:

• Bourne-Again Shell (Bash): Default shell in most Linux distributions.

• Z Shell (Zsh): Advanced shell with additional features.

• Korn Shell (ksh): Known for scripting capabilities.

• Fish Shell: User-friendly and interactive.

Shell Functions:

• Command execution

• Scripting (e.g., automating tasks through shell scripts)

• Customization (e.g., aliases, environment variables)

4. System Libraries

System libraries provide standard functions that allow user programs to interact with the kernel without needing to implement low-level system calls directly. These libraries simplify application development.

Examples:

• GNU C Library (glibc): Commonly used for standard input/output, memory allocation, and string operations.

• Dynamic Linking Libraries (DLLs): Shared libraries loaded during program execution.

5. System Utilities

System utilities are essential tools and programs used for system management and maintenance. These are divided into:

• Basic Utilities: File operations, disk management, and text processing.

• Administrative Utilities: User management, software installation, and system configuration.

Examples:

• ls, cat, grep (basic commands)

• systemctl, useradd, apt or yum (administrative commands)

6. User Applications

At the top layer, user applications are software programs used by end users. These programs leverage system libraries and kernel functions for execution.

Examples:

• Graphical Applications: Browsers (e.g., Firefox), office suites (e.g., LibreOffice), media players.

• Development Tools: Compilers (e.g., GCC), editors (e.g., Vim, Emacs).

• Server Applications: Web servers (e.g., Apache, Nginx), databases (e.g., MySQL, PostgreSQL).