Filesystem creation prepares a disk device (or partition) for use. Linux usually uses the native ext3 (third extended) journaling filesystem, but it supports many other filesystem types. You can see a list of all the filesystems Linux supports by using the “l” option under the fdisk command.
The Linux filesystem is arranged into a hierarchical structure anchored at the root directory, or /. Beneath this is a tree of directories and files.
Identification information for a filesystem object is stored in its inode (index node), which holds location, modification, and security information. Filesystems are created with a finite number of inodes.