Android Device File System Structure

Android Device directory structure is not fixed as in normal Linux but the following are typical:

 /system/bin – native utilities
 /system/xbin – more native utilities
 /system/etc – configuration files
 /system/apps – location of apps as apk or odex files
 /system/framework – application framework files (jar)
 /storage/sdcard – accessible outside of the phone (rw)
 /data – applications data (rw)
 /proc – proc file system
 /sys – sys file system
 /proc/crypto – encryption/signing schemes
 

ref:

Android Kernel vs Linux Kernel - http://www.all-things-android.com/content/android-kernel-versus-linux-kernel

Understanding the Android File Hierarchy - http://www.all-things-android.com/content/understanding-android-file-hierarchy

http://techblogon.com/android-file-system-structure-architecture-layout-details/