Android and android Official Website
Android operating system structure
Address: http://blog.csdn.net/caroline_wendy
Structure chart:
1. Linux kernel (kernel space)Portability, security, and practical functions.
2. Local layer (user space)
(1) HAL (Hardware action Layer): The Hardware Abstraction Layer abstracts every major device driver using a shared local library. This library is an object that supports common interfaces of any major hardware drivers.
(2) Local Database: C/C ++ library, supporting the Android Application Framework layer.
(3) Local daemon: Daemon process is a background service process in Linux. Service Manager, Radio Interface Layer Daemon, Install Daemon, and Media Server) android Debug Bridge Daemon;
(4) local tools:Linux Command Line tool to start the init process of all local daemon processes.
3. The Delvik virtual machine is an Android virtual machine that compiles Java bytecode into Delvik bytecode again, mainly based on the Java Standard Edition;
4. A large number of libraries and services of the application framework, a wide range of documents, Java libraries built for Android, And Java standard libraries;
5. Applications
(1) Application Package (APK, Android Application Package ):Android Manifest file, Dalvik executable file (. dex), resource, local library (library in other languages), signature (author of the application );
(2) Application signature:Each application has a signature, or uses the default signature. Location:. Android/debug. keystore.
(3) Application distribution:Google market, other markets.
