We're constantly very appreciative of the help provided by open source developers and communities. During the course of this project, we used a lot of open source tools and got a lot of inspiration from answers to open questions. In no particular order, we'd like to express our gratitude to developers and communities of BusyBox, Android, Gnu Toolchain, Buildroot, Ubuntu, Linux Kernel, and other utilities from the embedded system world.

I wish to acknowledge my sincere appreciation for Nicholas McGuire and Qingguo Zhou, who were my university instructors; they brought me into the Linux world. I want to thank the team members from the Open Source Community of Lanzhou University, who worked with me to build an excellent Linux system study environment. Many thanks to our previous and current colleagues, who discussed embedded system issues together and strengthened my embedded system experience a lot.

I also want to thank Cao Ziqiang, the co-author of this book; without his professional work, it would have been impossible to complete this book on time. And many thanks to my girlfriend, Rogina Lee, for her patient support and encouragement in the writing process.

Finally, thanks to Packt Publishing, who invited us and gave us the opportunity to discuss embedded system optimization with developers from all over the world. A special thank you to the production team and the reviewers who worked with us during this project and gave us guidance and feedback.

Cao Ziqiang is a Linux fan since 2004, and has more than eight years of experience in using the Linux operating system. He has extensive experience in video programs and network programs in C/C++ under Linux and has also majored in Linux kernel and device-driver development. In recent years, he has paid more attention to system stability and robustness, and worked for a smartphone company that uses Android as their main software platform. He is good at analyzing and resolving problems at the development phase using Linux tools such as toolbox, BusyBox, and some other open source projects of the Linux community. As a participant, he tested and fixed bugs in the Google Samsung kernel community. This is his first book as a co-author. He sincerely believes in the sharing of experience, which he has done with this book, and he will not stop sharing.