/os01

The original book in PDF and the accompany source code

Primary LanguageMakefile

Operating Systems: From 0 to 1

This book helps you gain the foundational knowledge required to write an operating system from scratch. Hence the title, 0 to 1.

After completing this book, at the very least:

  • How to write an operating system from scratch by reading hardware datasheets. In the real world, it works like that. You won't be able to consult Google for a quick answer.

  • Write code independently. It's pointless to copy and paste code. Real learning happens when you solve problems on your own. Some examples are given to kick start, but most problems are yours to conquer. However, the solutions are available online for you to examine after giving a good try.

  • A big picture of how each layer of a computer is related to the other, from hardware to software.

  • Linux as a development environment and how to use common tools for low-level programming.

  • Understand x86 assembly in-depth.

  • How a program is structured so that an operating system can run.

  • How to debug a program running directly on hardware with gdb and QEMU.

  • Linking and loading on bare metal x86_64, with pure C. No standard library. No runtime overhead.

Download the book

Prerequisites

Know some circuit concepts:

  • Basic Concepts of Electricity: atom, electrons, proton, neutron, current flow.
  • Ohm law

However, if you know absolute nothing, you can quickly learn it here: http://www.allaboutcircuits.com/textbook/, by reading chapter 1 and chapter 2.

Know some C programming. In particular:

  • Variable and functions declaration/definitions

  • While and for loops.

  • Understand how pointers work.

  • Fundamentals of algorithm and data structure in C.

Know Linux basics:

  • Know how to navigate directories with the command line

  • Know how to invoke a command with options.

  • Know how to pipe output to another program.

Know how to touch type. Since we are going to use Linux, touch typing helps. I know typing speed does not relate to problem -solving, but at least the speed should be fast enough not to let it get it the way and degrade the learning experience.

In general, I assume that a reader acquired basic programming knowledge with C, and can use an IDE at its basic. That is, know how to press the Play button for building and running a program.

Status:

  • Part 1
    • Chapter 1: Complete
    • Chapter 2: Complete
    • Chapter 3: Almost. Currently, the book relies on the Intel Manual for fully explaining x86 execution environment.
    • Chapter 4: Complete
    • Chapter 5: Complete
    • Chapter 6: Complete
  • Part 2
    • Chapter 7: Complete
    • Chapter 8: Complete
  • Part 3
    • Chapter 9: Incomplete
    • Chapter 10: Incomplete
    • Chapter 11: Incomplete
    • Chapter 12: Incomplete
    • Chapter 13: Incomplete

Sample OS

This repository is the sample OS of the book that is intended as a reference material for part 3. It covers 10 chapters of the "System Programming Guide" (Intel Manual Volume 3), along with a simple keyboard and video driver for input and output. However, at the moment, only the following features are implemented:

  • Protected mode.
  • Creating and managing processes with TSS (Task State Structure).
  • Interrupts
  • LAPIC.

Paging and I/O are not yet implemented. I will try to implement it as the book progresses.