difference between ext3 and ext4 filesystems

[jibinthomas]

1. Ext3 stands for third extended file system.
Ext4 stands for fourth extended file system.
2. ext3 Supports from Linux Kernel 2.4.15
ext4 Supports from Linux Kernel 2.6.19
3. Overall ext3 file system size can be from 2 TB to 32 TB
Overall maximum ext4 file system size is 1 EB (exabyte).