Refference
1. How to understand the directory structure of android root tree?
http://stackoverflow.com/questions/9046572/how-to-understand-the-directory-structure-of-android-root-tree
2. elinux
http://elinux.org/Android-4.1.1_r4
Android.StructureOfAndroidSourceCodeRootTree
原文：http://www.cnblogs.com/cwgk/p/4090269.html