Ubuntu from the begining used uuid as an identification in fstab mount point. Every partition has its own unique uuid. Uuid is Universally Unique Identifier. DIfferent with other linux distros that still using sda/ hda identifier.

We can find out the uuid in the /etc/fstab for each partition the ubuntu mount. But of course there are commands to find it out easily in the terminal.
Here are the commands:

We may use the uuid to mount any partition we have in /etc/fstab.
But fstab could still be wrote in hda/sda format.