Android File System Hierarchy

Use ► to navigate the file system
Mouse over on Folder name to get details

•   /  
                  Base file system : Generally recreated everytime using ramdisk content
  • cache
            Cache Folder : Used as scratch pad by OS place dex optimized dalvik bitecode
  • data
             Contains USER Data Stored as a separate partition in mtdblocks mounted at bootup
    • anr
    • idd
    • system
    • radio
    • property
    • app
              Application : User installed
    • data
              Downloaded, updated and manually installed apps
      • folder for each app named as package name.
    • local
    • dalivk-cache
      
  • default.prop
            Default Property settings, Values restored from this file on every restart
  • dev
            Device file system pointers
    • tty 1 - 63
    • null
    • zero
    • block
              Block Devices
      • loop 0-7
                Loop back devices
      • mtdblock 0 - 6-8
                MTD BLOCKS : Device internal memory
      • mmcblk0
                SDCARD Block Device
      • mmcblk0p1-64
                SDCARD partition Numbered
        
  • etc -> /system/etc
            Soft link to /system/etc Directory
    
  • hw_config.sh
  • init
            INIT executable, this is also the place where device nodes are created by listening to uevents
  • init.rc
            Initial Configuration file : decompressed from ramdisk
  • logo.rle
            Boot Time Logo
    
  • proc
    • last_kmsg
              Previous Sessions Kernel message log
    • partitions
    • diskstats
    • kmsg
              Kernel Message log simmilar to dmesg in linux
    • cpuinfo
              CPU information simmillar to linux
    • config.gz
              Copy of .config used to compile kernel (optional)
      
  • root
  • sbin
            Part of Ramdisk Content : This contains various executables required for Bootup
    • adbd
              ADB Daemon executable: Responsible for adb shell
      
  • sys
    • fs
    • devices
    • dev
    • bus
    • class
    • firmware
    • kernel
    • power
    • module
    • block
      
  • system
            Main OS System
    Stored as a separate partition in mtdblocks mounted at bootup (read-only)
    • app
              System Apps : Pre installed : Android Specific, Vendor and Carrier Provided Application set.
               These applications can't be changed without rooting device(till version 4.0 of android)
      
    • bin
              Binary Executables required for operation
      • installd
                Native package management daemon
      • keystore
                keystore for android
      • netd
                 Communication daemon
      • rild
                modem communication
      • system_server
                Key server in android performing most critical task and providing most services. Combination of cpp and java code.
                The system server communicates with vold/rild etc
      • vold
                Volume manager that listens to kernel netlink events and mounts media
    • build.prop
              File containing Configuration variables used to define various operational parameters
    • etc
              Configuration Files for Whole Android System
    • framework
              Framework : jar Files which provision the interaction between applications and hardware
    • fonts
              Fonts used in display
    • media
              Contains Media files ringtone/alarms etc
    • xbin
              Excutable Files generally this holds special executables like busybox or toolbox
  • sdcard
            SDCARD :removable sdcard directory
  • mnt
    • sdcard -> /sdcard
              Link too /sdcard
      
      • asec
                SDCARD Secure area

Changelog

11 Dec 2011

1. Updated lots of data based on details from https://github.com/keesj/gomo/wiki/AndroidUserland and user comments
2. Not just mouseover text is also available next to folders now.