Questions about: ext4

ext2, ext3 and ext4 are all filesystems created for Linux. This article explains the following: High level difference between these filesystems. How to create these filesystems
On Ubuntu 10. 04, relatime is part of the default mount options, unless overridden in /etc/fstab. The previous few releases had relatime explicitly in /etc/fstab
GUI (Ubuntu 14. 04 and later): GParted v0. 17 and later provide a nice GUI for this