5.8. Automounter Filesystems

Before you can access files on any filesystem using Linux, it must first be explicitly mounted. This is fine for hard disks that are mounted at boot time, but is not so convenient for removable media like CD-ROMs, floppy disks, and Zip disks. Having to mount a floppy before you can read or write files on it, and then unmount it when done, is not very user friendly—especially compared to other operating systems like Windows.

Fortunately, there is a solution—the automounter filesystem. This system does not contain any files of its own, but automatically creates temporary directories and mounts filesystems when needed. An automounter filesystem mounted at /auto would normally be configured to mount a floppy disk at /auto/floppy as soon as a user tries to cd into that directory. When the floppy's filesystem is no longer being used, it will be automatically unmounted so that the floppy can be safely ejected.

Automounter filesystems can be created, viewed and edited in Webmin. Each has a configuration file that specifies which devices it will mount and which subdirectories on which they will be mounted. The editing of these configuration files cannot be done within Webmin, however—you can only choose which one to use. Most modern Linux distributions come with an automounter filesystem at /auto or /media set up by default, and configured to allow access to floppy and CD-ROM drives.

Another common use for the automounter is to provide easy access to NFS servers. Often an automounter on the /net directory is set up so that accessing the /net/hostname directory will mount all the exported directories from hostname under that directory. This is all done using another automounter configuration file.