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0xax/linux-insides

Analysis updated 2026-06-20

★ 32,534PythonAudience · developerComplexity · 5/5LicenseSetup · easy

TLDR

A free online book that explains how the Linux kernel actually works internally, from the first moment a computer boots through memory management, system calls, and process scheduling.

Mindmap

mindmap
  root((linux-insides))
    What it does
      Linux kernel book
      Explains internals
      Free to read online
    Topics covered
      Boot process
      System calls
      Memory management
      Process scheduling
    Audience
      Systems developers
      Kernel contributors
      OS learners
    Prerequisites
      C programming
      Basic assembly
    Languages available
      English
      Chinese
      Russian
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What do people build with it?

USE CASE 1

Learn how the Linux kernel boots a computer, step by step, from power-on through CPU and memory initialization.

USE CASE 2

Understand how system calls work at the kernel level to become a better systems programmer or debugging engineer.

USE CASE 3

Study Linux memory management and process scheduling internals when contributing to or debugging kernel-level code.

What is it built with?

CAssemblyPython

How does it compare?

0xax/linux-insidesopen-mmlab/mmdetectiontinygrad/tinygrad
Stars32,53432,53332,501
LanguagePythonPythonPython
Setup difficultyeasyhardhard
Complexity5/54/55/5
Audiencedeveloperresearcherresearcher

Figures from each repo's GitHub metadata at analysis time.

How do you get it running?

Difficulty · easy Time to first run · 5min

No setup needed, read the book directly on GitHub, prior knowledge of C and basic assembly is required to follow the content.

Licensed under Creative Commons BY-NC-SA, free to read and share with attribution, but commercial use is not allowed and derivatives must use the same license.

In plain English

linux-insides is a free, ongoing book about the internal workings of the Linux kernel, the core software that manages hardware resources and runs on every Linux-based system. The book walks readers through what actually happens inside the kernel, starting from the earliest moment a computer boots and progressing through initialization, interrupt handling, system calls, memory management, timers, synchronization, and more. The goal is not to teach Linux usage or system administration, but to explain the actual code and mechanisms inside the kernel itself. Each chapter covers a specific subsystem or concept, for example, how the kernel sets up the CPU and memory during boot, how it manages processes sharing a CPU safely, or how memory is allocated and tracked. The content references the actual kernel source code and explains the data structures, algorithms, and low-level assembly and C code that implement these features. Reading this book requires prior knowledge of the C programming language and some familiarity with assembly language (the low-level instructions that directly control CPU hardware). It is aimed at developers who are curious about operating system internals, kernel contributors, or engineers working on system-level software who want to understand what is happening below the library and application layers. The repository began when the kernel was at version 3.18 and is being updated to reflect modern kernels (v6.18 and later). The "primary language" listed as Python refers to tooling in the repository rather than the book content itself, which covers C and assembly. Community translations exist in Chinese, Japanese, Korean, Russian, Portuguese, Spanish, and Turkish. The book is freely readable on GitHub and is licensed under Creative Commons BY-NC-SA.

Copy-paste prompts

Prompt 1
I'm reading linux-insides by 0xax. Explain what happens in the first 500 bytes of the Linux boot process in plain terms, as if I know C but have never looked at kernel code.
Prompt 2
Based on the linux-insides book, explain how Linux handles a system call like read() from the moment user code calls it to when the kernel returns the data.
Prompt 3
I want to understand Linux memory management using linux-insides as a guide. Walk me through how the buddy allocator works and why it was designed that way.
Prompt 4
Help me understand the interrupt handling chapter of linux-insides. What is an interrupt descriptor table and why does the kernel need one?

Frequently asked questions

What is linux-insides?

A free online book that explains how the Linux kernel actually works internally, from the first moment a computer boots through memory management, system calls, and process scheduling.

What language is linux-insides written in?

Mainly Python. The stack also includes C, Assembly, Python.

What license does linux-insides use?

Licensed under Creative Commons BY-NC-SA, free to read and share with attribution, but commercial use is not allowed and derivatives must use the same license.

How hard is linux-insides to set up?

Setup difficulty is rated easy, with roughly 5min to a first successful run.

Who is linux-insides for?

Mainly developer.

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