File-System Mounting

File-System Mounting

·         The basic idea behind mounting file systems is to combine multiple file systems into one large tree structure.

·         The mount command is given a filesystem to mount and a mount point ( directory ) on which to attach it.

·         Once a file system is mounted onto a mount point, any further references to that directory actually refer to the root of the mounted file system.

·         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 by root, unless root has previously configured certain filesystems to be mountable onto certain pre-determined mount points. ( E.g. root may allow users to mount floppy filesystems to /mnt or something like it. ) Anyone can run the mount command to see what filesystems are currently mounted.

·         Filesystems may be mounted read-only, or have other restrictions imposed.

·         The traditional Windows OS runs an extended two-tier directory structure, where the first tier of the structure separates volumes by drive letters, and a tree structure is implemented below that level.

·         Macintosh runs a similar system, where each new volume that is found is automatically mounted and added to the desktop when it is found.

·         More recent Windows systems allow filesystems to be mounted to any directory in the filesystem, much like UNIX.