File Mounting and Paths

Mounting is the action of establishing access to a directory of files that are stored on the disk. Once access is established, the OS can access the files and the directories inside the mount point, which is the top (root) directory.

The basic idea behind mounting file systems is to combine multiple file systems into one large tree structure. A file system is the directories and files within these directories, which form a shape of a tree.

Any files (or sub-directories) that had been stored in the mount point directory prior to mounting the new filesystem are now hidden by the mounted filesystem, and are no longer available. For this reason some systems only allow mounting onto empty directories.

Filesystems can only be mounted at the root directory, unless the filesystem has been previously configured to be mountable at pre-determined mount points that are other than the root.