The fstab file is a text file that contains information about the various file systems and storage devices on your computer. It is just one file that defines how the disk and/or partition will be used and how it will be integrated into the rest of the system. The full path to the file is /etc/fstab. This file can be opened in any text editor, but it can only be edited as a sudo, because the file is an important, integral part of the system; without it, the system will not boot.