这是fork项目的中文翻译版本。希望在这个过程中对OS有深一步的认识。翻译过程中，较原版项目增加了一些内容、笔记。
原作者更新到24章便没有啥动静了。总体评价的话，这是一个非常初级的OS教程。个人感受，OS完成度也就20%吧，或者说开了个头制作了一个启动盘而已。
总结一下大致脉络。
- 首先这是以32位x86架构为目标的OS
- 01-07部分，聚焦在512K的启动盘上。x32下16位汇编为主。
- 08，09，10 三章，改造之前程序，进入32位保护模式，为内核入口程序作准备
- 11章，折腾交叉编译工具链gcc等工具套件。（这里用Mac有大坑，原作者也在24章重新填坑了）
- 11-14章，将启动盘的入口程序，与C程序对接完成。屏幕有字符打印
- 15、16、17章，解决屏幕字符打印。可以粗糙的打印字符了。
- 19-21章，中断处理，键盘输入可以打印到屏幕上。
- 22章，想实现malloc，分配堆内存。（看到这里就可以放弃了。粗糙的实现。作者从这左右开始借鉴其他教程的内容。）
- 23、24一章重构，一章填苹果系统的坑。
- 就没有然后了。。。
How to create an OS from scratch!
I have always wanted to learn how to make an OS from scratch. In college I was taught how to implement advanced features (pagination, semaphores, memory management, etc) but:
- I never got to start from my own boot sector
- College is hard so I don't remember most of it.
- I'm fed up with people who think that reading an already existing kernel, even if small, is a good idea to learn operating systems.
Inspired by this document and the OSDev wiki, I'll try to make short step-by-step READMEs and code samples for anybody to follow. Honestly, this tutorial is basically the first document but split into smaller pieces and without the theory.
Updated: more sources: the little book about OS development, JamesM's kernel development tutorials
- This course is a code tutorial aimed at people who are comfortable with low level computing. For example, programmers who have curiosity on how an OS works but don't have the time or willpower to start reading the Linux kernel top to bottom.
- There is little theory. Yes, this is a feature. Google is your theory lecturer. Once you pass college, excessive theory is worse than no theory because it makes things seem more difficult than they really are.
- The lessons are tiny and may take 5-15 minutes to complete. Trust me and trust yourself. You can do it!
-
Start with the first folder and go down in order. They build on previous code, so if you jump right to folder 05 and don't know why there is a
mov ah, 0x0e, it's because you missed lecture 02. Really, just go in order. You can always skip stuff you already know. -
Open the README and read the first line, which details the concepts you should be familiar with before reading the code. Google concepts you are not familiar with. The second line states the goals for each lesson. Read them, because they explain why we do what we do. The "why" is as important as the "how".
-
Read the rest of the README. It is very concise.
-
(Optional) Try to write the code files by yourself after reading the README.
-
Look at the code examples. They are extremely well commented.
-
(Optional) Experiment with them and try to break things. The only way to make sure you understood something is trying to break it or replicate it with different commands.
TL;DR: First read the README on each folder, then the code files. If you're brave, try to code them yourself.
We will want to do many things with our OS:
- Boot from scratch, without GRUB - DONE!
- Enter 32-bit mode - DONE
- Jump from Assembly to C - DONE!
- Interrupt handling - DONE!
- Screen output and keyboard input - DONE!
- A tiny, basic
libcwhich grows to suit our needs - DONE! - Memory management
- Write a filesystem to store files
- Create a very simple shell
- User mode
- Maybe we will write a simple text editor
- Multiple processes and scheduling
Probably we will go through them in that order, however it's soon to tell.
If we feel brave enough:
- A BASIC interpreter, like in the 70s!
- A GUI
- Networking
This is a personal learning project, and even though it hasn't been updated for a long time, I still have hopes to get into it at some point.
I'm thankful to all those who have pointed out bugs and submitted pull requests. I will need some time to review everything and I cannot guarantee that at this moment.
Please feel free to fork this repo. If many of you are interested in continuing the project, let me know and I'll link the "main fork" from here.