Don states that Ext4 is the extension to ext3 with journaling turned on. However, ext3 had journaling as well. It would have been helpful if differences between ext2 to ext4 could have been explained. Ext2 is one of the objective of Linux+ but has not been addressed in videos.
Ext3 and Ext4
EXT 2, 3, and 4 are technically the same filesystem with different features enabled. EXT3's big feature was journaling. EXT4's big feature was support for much larger files. I apologize if I misstated this in the video.