Mount
The Mediawiki system (the 'software' that runs this site) capitalises all articles. Please note that commands on most UNIX and Unix-like systems are entered in lower case. As an example the article documenting the Ln command would be issued from the command line as 'ln'.
The mount command is used to link a file system to the local host allowing access to files stored upon them. These file systems could be on physical media, such as a hard drive, CD-ROM or USB memory key, or virtual media, such as file server shares. FreeBSD has support for reading from a large number of file systems and can write back to a majority of them.
Operation
The mounting of a file system to the local host works by creating a mount-point at which the file system can be accessed. This fits in with the Unix concept of 'everything is a file' and as such a CD-ROM drive, for example, is typically mounted as '/cdrom'. Other file systems are typically mounted under the '/mnt' directory. The technical term is called 'grafting' a device to the local file system tree.
An typical installation of FreeBSD might have the following mount-points:
/ - file system root; /var - log files; /usr - user specific directories, ports, etc.; /tmp - temporary workspace; /cdrom - physical CD-ROM drive.
These mount-points are automatically mounted when the system is started because they are stored in a file called '/etc/fstab' or 'f'ile 's'ystem 't'able. The fstab file used to mount the above listed mount-points contains the following entires:
# Device Mountpoint FStype Options Dump Pass# /dev/ad0s1b none swap sw 0 0 /dev/ad0s1a / ufs rw 1 1 /dev/ad0s1e /tmp ufs rw 2 2 /dev/ad0s1f /usr ufs rw 2 2 /dev/ad0s1d /var ufs rw 2 2 /dev/acd0 /cdrom cd9660 ro,noauto 0 0
The mounted file systems are physical devices located under the /dev directory with the hard drive being 'ad0s1x' and CD-ROM being 'acd0' on this particular system. The 'none' mount-point simply exists to inform the system of where the swap-file (often called 'virtual memory') is located. Further details of the fstab file can be found in the fstab article.
Mount Commands
The mount command exists on its own a command to mount FreeBSD formatted file systems. In order to permit the mounting of 'foreign' (or non-native FreeBSD formatted) file systems each supported file system has its own mount command using the common naming scheme of 'mount_filesystem'. The command to mount an 'MS-DOS' (or DR-DOS, FAT16 or FAT32) formatted file system the command is 'mount_msdosfs'. The file systems available to FreeBSD and the associated mount commands are as follows:
