==ext4 studies==
http://kernelnewbies.org/Ext4


ext4 doc: https://www.kernel.org/doc/Documentation/filesystems/ext4.txt



==journal studies==
http://stackoverflow.com/questions/7479414/android-filesystem-journaling


check if fs has journal: http://askubuntu.com/questions/76913/how-can-i-check-if-a-particular-partition-ext4-is-journaled


==enabling boot0 boot1 device==
http://www.gossamer-threads.com/lists/linux/kernel/1431505