FSTAB(5)							File Formats Manual							  FSTAB(5)

NAME

       fstab - static information about the filesystems

SYNOPSIS

       #include <fstab.h>

DESCRIPTION

       The file fstab contains descriptive information about the various file systems.	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) sequen-
       tially iterate through fstab doing their thing.

       The first field, fs_spec, describes the block special device or remote filesystem to be mounted.  For filesystems of type ufs, the  special
       file name is the block special file name, and not the character special file name.  If a program needs the character special file name, the
       program must create it by appending a ``r'' after the last ``/'' in the special file name.

       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 only two types of filesystems:

       ufs	      a local UNIX filesystem

       swap	      a disk partition to be used for swapping

       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 (see fs_type below) plus any additional options appropriate to the filesystem type.

       If  the	option	``quotas''  is specified, the filesystem is automatically processed by the quotacheck(8) command, and user disk quotas are
       enabled with quotaon(8).  Filesystem quotas are maintained in the file named quotas located at the root of the associated filesystem.  This
       restriction  on	the  location  of  the quotas file is needlessly imposed by the kernel but may be lifted in the future.  Thus, if the user
       quota file for /tmp is stored in /var/quotas/tmp.user, this location can be specified as:

	      quotas=/var/quotas/tmp.user

       The type of the mount is extracted from the fs_mntops field and stored separately in  the  fs_type  field  (it  is  not	deleted  from  the
       fs_mntops  field).   If	fs_type is ``rw'' or ``ro'' then the filesystem whose name is given in the fs_file field is normally mounted read-
       write or read-only on the specified special file.  If fs_type is ``sw'' then the special file is made available as a piece of swap space by
       the  swapon(8)  command	at  the  end of the system reboot procedure.  The fields other than fs_spec and fs_type are unused.  If fs_type is
       specified as ``xx'' the entry is ignored.  This is useful to show disk partitions which are currently unused.

       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(8) will assume that the filesystem does not need to be dumped.

       The  sixth field, fs_passno, is used by the fsck(8) program to determine the order in which filesystem checks are done at reboot time.  The
       root filesystem should be specified with a fs_passno of 1, and other filesystems should have a fs_passno of 2.  Filesystems within a  drive
       will  be checked sequentially, but filesystems on different drives will be checked at the same time to utilize parallelism available in the
       hardware.  If the sixth field is not present or zero, a value of zero is returned and fsck(8) will assume that the filesystem does not need
       to be checked.

       #define	 FSTAB_RW  "rw" /* read-write device */
       #define	 FSTAB_RO  "ro" /* read-only device */
       #define	 FSTAB_SW  "sw" /* swap device */
       #define	 FSTAB_XX  "xx" /* ignore totally */

       struct fstab {
	    char *fs_spec; /* block special device name */
	    char *fs_file; /* filesystem path prefix */
	    char *fs_vfstype;	/* type of filesystem */
	    char *fs_mntops;	/* comma separated mount options */
	    char *fs_type; /* rw, ro, sw, or xx */
	    int  fs_freq;  /* dump frequency, in days */
	    int  fs_passno;	/* pass number on parallel dump */
       };

       The proper way to read records from fstab is to use the routines getfsent(3), getfsspec(3), getfstype(3), and getfsfile(3).

FILES

       /etc/fstab     The file fstab resides in /etc.

SEE ALSO

       getfsent(3)

HISTORY

       The fstab file format appeared in 4.0BSD.

4.4 Berkeley Distribution					 January 15, 1996							  FSTAB(5)