The Android system compiles three image files, all packaged with CPIO, gzip compressed.
- Ramdisk.img file system, including/system,/data,/bin and other directories. Kernel is responsible for initialization at startup.
- SYSTEM.IMG System Package and library file, mount to/system directory
- USERDATA.IMG user data, mount to/data directory
Android System directory structure
- /init System Boot File
- /system
- App installation directory
- bin Common system local commands (binary), mostly toolbox links (similar to busybox in embedded Linux)
- etc System configuration files, such as the hosts
- Font Fonts directory
- Framework Java Platform Architecture Core libraries, jar packages and Odex optimized files
- Lib system underlying shared library,. So library files
- xbin less commonly used system management tools, equivalent to the/sbin of Linux
- Media
- Audio ringtones, beep tones, etc.. ogg
- Notifications Notice
- UI interface
- Alarms Warning
- Ringtones ringtones
- usr user folder
- Keychars
- Keylayout
- Share
- SREC Configuration
- ......
- Vendor
- Build.prop system settings and change properties
- ETC--/SYSTEM/ETC
- /vendor-/system/vendor
- /dev Store device node files
- /proc Global System Information
- /dataUser software and various data
- local/tmp Temp directory, no permission required
- App General program installation directory
- System
- Location where the Location.gps records the final coordinates, locationmanager.getlastknownlocation () data from here
- Data
- <package_name>
- Files Context.getfilesdir (), Context.openfileoutput () Gets the directory under Application installation directory
- Cache Context.getcachedir () Gets the directory, under the application installation directory, the system automatically cleans up when there is not enough or when the directory size reaches a certain value.
- Shared_pref Context.getsharedpreferences () established preferences file (XML) storage directory
- When the ANR application occurs in the Applicaiton is not responding, Android writes the stack of the problem point to the Traces.txt file
- Location
- GPS Location Provider Configuration
- property where Persist.sys.timezone records the system time zone
- /sdcard -->/storage/emulated/legacy SD card FAT32 file system mount to this directory
- Android
- Data
- <package_name> Application of additional data, application uninstall automatically deleted.
- Files Context.getexternalfilesdir () Gets the directory. Settings, application-specific application details, clear data operand is this directory.
- Cache Context.getexternalcachedir () gets the cache directory. Settings, application-specific application details, clear cache Operation object is this directory.
Lost+found
The yaffs file system is inherently similar to the Recycle Bin folder.
ODEX
The executable file extracted from the APK, which is a separately stored Dex file created by Dex optimization in the original apk classes.dex. It's faster to start the app without extracting Dex from the APK package. You can also delete the Dex in the APK package to reduce the volume. The disadvantage is that the volume becomes larger, and upgrading an application to Odex may cause problems.
Reference documents
http://blog.csdn.net/conowen/article/details/7251057
Android System directory structure
