(Inside of Android Technology: System Volume, an electronic book in pdf format, is based on the source code of the Android system, deeply analyzes the architecture design and implementation principle of the Android kernel, and thoroughly analyzes the underlying mechanism of various functional modules of the Android kernel layer, hardware general layer, and system runtime layer. This book is the first work of in-depth analysis of Android source code by the system in China. The whole book divides the Android system into five layers from the perspective of architecture: the use layer, the use framework layer, the system runtime layer, the general hardware layer and the Linux kernel layer. It aims to help developers deepen their understanding of the architecture design and implementation principles of the Android system through any analysis of the source code of the Android system, and then help them solve the increasingly messy problems encountered in development.)