Linux Complete Command Reference:File Formats:EarthWeb Inc.-

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Page 1125

SEE ALSO

mountd(8), nfsd(8), nfs(5), passwd(5)

21 October 1996

The file fstab contains descriptive information about the various filesystems. fstab is only read by programs and not written; it is the duty of the system administrator to properly create and maintain this file. Each filesystem is described on a separate line; fields on each line are separated by tabs or spaces. The order of records in fstab is important because fsck(8), mount(8), and umount(8) sequentially iterate through fstab doing their thing.

The first field (fs_spec) describes the block special device or remote filesystem to be mounted.

The second field (fs_file) describes the mount point for the filesystem. For swap partitions, this field should be specified as none.

The third field (fs_vfstype) describes the type of the filesystem. The system currently supports three types of filesystems:

minix	A local filesystem, supporting filenames of length 14 or 30 characters.
ext	A local filesystem with longer filenames and larger inodes. This filesystem has been replaced by the ext2 filesystem and should no longer be used.
ext2	A local filesystem with longer filenames, larger inodes, and a lot of other features.
xiafs	A local filesystem with longer filenames, larger inodes, and a lot of other features.
msdos	A local filesystem for MS-DOS partitions.
hpfs	A local filesystem for HPFS partitions.
iso9660	A local filesystem used for CD-ROM drives.
nfs	A filesystem for mounting partitions from remote systems.
Swap	A disk partition to be used for swapping.

If vfs_fstype is specified as ignore, the entry is ignored. This is useful to show disk partitions that are currently unused.

The fourth field (fs_mntops) describes the mount options associated with the filesystem.

It is formatted as a comma-separated list of options. It contains at least the type of mount plus any additional options appropriate to the filesystem type. For documentation on the available options for non-NFS file systems, see mount(8). For documentation on all NFS-specific options, take a look at nfs(5). Common for all types of filesystems are the options noauto (do not mount when mount -a is given, such as at boot time) and user (allow a user to mount). For more details, see mount(8).

The fifth field (fs_freq) is used for these filesystems by the dump(8) command to determine which filesystems need to be dumped. If the fifth field is not present, a value of zero is returned and dump will assume that the filesystem does not need to be dumped.

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minix	The filesystem used in the Minix operating system, the first to run under Linux. It has a Vnumber of shortcomings: a 64MB partition size limit, short filenames, a single time stamp, and so on. It remains useful for floppies and RAM disks.
ext	An elaborate extension of the minix filesystem. It has been completely superseded by the second version of the extended filesystem (ext2) and will eventually be removed from the kernel.
ext2	The high performance disk filesystem used by Linux for fixed disks as well as removable media. The second extended filesystem was designed as an extension of the extended filesystem (ext). ext2 offers the best performance (in terms of speed and CPU usage) of the filesystems supported under Linux.
xiafs	Designed and implemented to be a stable, safe filesystem by extending the Minix filesystem code. It provides the basic, most requested features without undue complexity. The xia filesystem is no longer actively developed or maintained. It is used infrequently.
msdos	The filesystem used by DOS, Windows, and some OS/2 computers. msdos filenames can be no longer than an eight-character name followed by an optional period and three-character extension.
umsdos	An extended DOS filesystem used by Linux. It adds capability for long filenames, UID/GID, POSIX permissions, and special files (devices, named pipes, and so on) under the DOS filesystem, without sacrificing compatibility with DOS.
vfat	Extended DOS filesystem used by Microsoft Windows 95 and Windows NT. vfat adds capability for long filenames under the MS-DOS filesystem.
proc	A pseudo-filesystem that is used as an interface to kernel data structures rather than reading and interpreting /dev/kmem. In particular, its files do not take disk space. See proc(5).
iso9660	A CD-ROM filesystem type conforming to the ISO 9660 standard.
High Sierra	Linux supports High Sierra, the precursor to the ISO 9660 standard for CD-ROM filesystems. It is automatically recognized within the iso9660 filesystem support under Linux.
Rock Ridge	Linux also supports the System Use Sharing Protocol records specified by the Rock Ridge Interchange Protocol. They are used to further describe the files in the iso9660 filesystem to a UNIX host and provides information such as long filenames, UID/GID, POSIX permissions, and devices. It is automatically recognized within the iso9660 filesystem support under Linux.
hpfs	The High Performance Filesystem, used in OS/2. This filesystem is read-only under Linux due to the lack of available documentation.
sysv	An implementation of the SystemV/Coherent filesystem for Linux. It implements all Xenix FS, SystemV/386 FS, and Coherent FS.
nfs	The network filesystem used to access disks located on remote computers.

smb	A network filesystem that supports the SMB protocol, used by Windows for Workgroups, Windows NT, and LAN Manager.
	To use smb, you need a special mount program, which can be found in the ksmbfs package at ftp://sunsite.unc.edu/pub/Linux/system/Filesystems/smbfs.
ncpfs	A network filesystem that supports the NCP protocol, used by Novell NetWare.
	To use ncpfs, you need special programs found at ftp://linux01.gwdg.de/pub/ncpfs.