1¡¢ext2 used to be the most common Linux filesystem
2¡¢ext3 is based on ext2
3¡¢Same on-disk structure
4¡¢ext2 can be converted to ext3
5¡¢ext3 can be mounted as an ext2 file system
6¡¢ext3 is a journaling filesystem£¬Preserves data integrity better than ext2£¬Faster and safer fsck after system crash