Table of Contents
The file
contains descriptive information about the various file systems. 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 is important because and sequentially iterate
through doing their thing. The first field, describes the block special
device or remote filesystem to be mounted. For filesystems of type 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, describes the mount point for the filesystem.
For swap partitions, this field should be specified as ‘‘none’’. The third
field, describes the type of the filesystem. The system currently supports
eleven types of filesystems: An filesystem an ISO 9660 CD-ROM filesystem
an implementation of /dev/fd a local filesystem various and sundry
kernel statistics a local memory-based filesystem a MSDOS ‘‘FAT’’ filesystem
a Sun Microsystems compatible ‘‘Network File System’’ a local filesystem
of process information a disk partition to be used for swapping a translucent
filesystem The fourth field, 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 below) plus any additional
options appropriate to the filesystem type. If the options ‘‘userquota’’ and/or
‘‘groupquota’’ are specified, the filesystem is automatically processed by
the command, and user and/or group disk quotas are enabled with By default,
filesystem quotas are maintained in files named and which are located
at the root of the associated filesystem. These defaults may be overridden
by putting an equal sign and an alternative absolute pathname following
the quota option. Thus, if the user quota file for is stored in this location
can be specified as: userquota=/var/quotas/tmp.user The type of the mount
is extracted from the field and stored separately in the field (it is
not deleted from the field). If is ‘‘rw’’ or ‘‘ro’’ then the filesystem whose
name is given in the field is normally mounted read-write or read-only on
the specified special file. If is ‘‘sw’’ then the special file is made available
as a piece of swap space by the command at the end of the system reboot
procedure. The fields other than and are unused. If is specified as ‘‘xx’’
the entry is ignored. This is useful to show disk partitions which are currently
unused. The fifth field, is used for these filesystems by the command
to determine which filesystems need to be dumped. If the fifth field is
not present, a value of zero is returned and will assume that the filesystem
does not need to be dumped. The sixth field, is used by the program to
determine the order in which filesystem checks are done at reboot time.
The root filesystem should be specified with a of 1, and other filesystems
should have a 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 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 is to use the routines and
The file resides in
The file format appeared
in
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