January 20, 2025 3 min to read

What is Linux Kernel?

A comprehensive guide to the Linux Kernel architecture and functionality

Overview

Let’s explore the Linux Kernel, the core component of the Linux operating system that manages hardware resources and provides essential services to system processes.

What is the Linux Kernel?

The kernel is the core part of any operating system. It’s the layer that communicates directly with hardware and provides essential services to applications and system processes.

Linux specifically uses a “monolithic” kernel design, meaning most core system functions (file system management, device drivers, memory management, etc.) are included within a single large binary.

🔄 Linux Kernel Architecture:

Main Responsibilities

Key Components

1️⃣ System Call Interface

# Example of a system call in C
#include <stdio.h>
#include <unistd.h>

int main() {
    pid_t pid = fork();  // fork() is a system call
    if (pid == 0) {
        printf("Child process\n");
    } else {
        printf("Parent process\n");
    }
    return 0;
}

2️⃣ Process Management

# View running processes
ps aux

# Check process priority
nice -n 10 ./my_program

# View process tree
pstree

3️⃣ Memory Management

# View memory usage
free -h

# Check virtual memory statistics
vmstat 1

# View detailed memory info
cat /proc/meminfo

Kernel Space vs User Space

Kernel Architecture Comparison

Advanced Features

1️⃣ Kernel Modules

# List loaded modules
lsmod

# Load a module
sudo modprobe bluetooth

# Remove a module
sudo rmmod bluetooth

# Module information
modinfo bluetooth

2️⃣ System Control

# View kernel parameters
sysctl -a

# Modify kernel parameter
sudo sysctl -w vm.swappiness=60

# Load kernel parameter changes
sudo sysctl -p

Security Features

Reference

• Red Hat - What is the Linux Kernel
• The Linux Kernel Archives
• Linux Kernel Documentation