I am USB in Linux. Preface to Version 2

It has been more than four years since I started writing the Linux series of things, and it has been quite a bit since I sorted out and published the first version. Some people who don't know or know each other asked me how I thought of writing so many cute words. My answer was to entertain myself and entertain everyone!

Perhaps we have already considered technology as a heavy or boring topic by default. We cannot look at it with an entertaining mindset, or even say that many people have lost the ability to enjoy it. However, we are willing or unwilling to step into this industry for whatever reason. Technology is an integral part of our lives.

In this case, why not take him as a friend and communicate with him in our own way, instead of simply treating him as a pile of dead code or a boring term. For the content of this book, I want to talk about the kernel as a friend. The smiling teacher has a book that treats time as a friend and tells us that only when we treat time as a friend can we make better use of our time to do useful things. Once your eyes are closed, one day has passed. Once your eyes are closed, the rest of your life has passed. Treat time and time to treat us well. Similarly, we can better understand and understand the essence of the kernel only when we treat it as a living entity and put it in a peer-to-peer status.

Specifically, you can use this book as a book for kernel source code analysis, or even a book for Kernel USB source code analysis, but I want you to take it as an example to show how to learn the Linux kernel and how to communicate equally with the kernel. At least it reflects the attitude we should take to the Linux kernel source code. That is to say, to analyze the kernel source code, Attitude determines everything. Many of us may have such confusion. We also analyzed and browsed many kernel source codes, but we always felt that the analysis was empty and we didn't feel much gains. At this time, we may be able to see if our attitude encountered a problem when analyzing the code. When we analyze the kernel source code, we must follow a rigorous attitude, instead of taking a leisurely view of the image. In the end, there will inevitably be great gains.

Then there is another saying that the level of technology doesn't depend on the skill of C or C ++, but on the amount of resources you have mastered. Therefore, we need to focus on the INCORE source code and adhere to the Construction of learning resources. In our kernel learning process, the kernel source code itself is the best reference material. Any other classic or non-classic books can only play a secondary role at most, it cannot or should not replace the dominant position of kernel code in our learning process. However, these auxiliary functions cannot be ignored. We need to focus on the INCORE source code and stick to the long-term construction of various learning resources.

Thanks again to Sun xuexiao for editing. Without her efforts, the content of this book will remain on the Internet and cannot be published to help more people who need it.