<s>
fstab	B-Protocol
(	O
after	O
file	B-Application
systems	I-Application
table	O
)	O
is	O
a	O
system	B-General_Concept
file	I-General_Concept
commonly	O
found	O
in	O
the	O
directory	O
/etc	B-Application
on	O
Unix	B-Application
and	O
Unix-like	B-Operating_System
computer	O
systems	O
.	O
</s>
<s>
In	O
Linux	B-Application
,	O
it	O
is	O
part	O
of	O
the	O
util-linux	B-Application
package	O
.	O
</s>
<s>
The	O
fstab	B-Protocol
file	O
typically	O
lists	O
all	O
available	O
disk	B-Application
partitions	I-Application
and	O
other	O
types	O
of	O
file	B-Application
systems	I-Application
and	O
data	O
sources	O
that	O
may	O
not	O
necessarily	O
be	O
disk-based	O
,	O
and	O
indicates	O
how	O
they	O
are	O
to	O
be	O
initialized	O
or	O
otherwise	O
integrated	O
into	O
the	O
larger	O
file	B-Application
system	I-Application
structure	O
.	O
</s>
<s>
The	O
fstab	B-Protocol
file	O
is	O
read	O
by	O
the	O
mount	B-Application
command	O
,	O
which	O
happens	O
automatically	O
at	O
boot	O
time	O
to	O
determine	O
the	O
overall	O
file	B-Application
system	I-Application
structure	O
,	O
and	O
thereafter	O
when	O
a	O
user	O
executes	O
the	O
mount	B-Application
command	O
to	O
modify	O
that	O
structure	O
.	O
</s>
<s>
It	O
is	O
the	O
duty	O
of	O
the	O
system	B-Application
administrator	I-Application
to	O
properly	O
create	O
and	O
maintain	O
the	O
fstab	B-Protocol
file	O
.	O
</s>
<s>
While	O
fstab	B-Protocol
is	O
used	O
for	O
basic	O
system	O
configuration	O
,	O
for	O
other	O
uses	O
,	O
it	O
has	O
been	O
superseded	O
by	O
automatic	O
mounting	B-Application
mechanisms	O
.	O
</s>
<s>
The	O
file	O
has	O
other	O
names	O
on	O
some	O
versions	O
of	O
Unix	B-Application
;	O
for	O
example	O
,	O
it	O
is	O
found	O
at	O
/etc/vfstab	O
on	O
Solaris	B-Application
systems	O
.	O
</s>
<s>
The	O
fstab	B-Protocol
file	O
is	O
read	O
by	O
programs	O
that	O
work	O
with	O
disk	B-Application
partitions	I-Application
and	O
other	O
file	B-Application
systems	I-Application
and	O
is	O
not	O
automatically	O
maintained	O
.	O
</s>
<s>
Instead	O
it	O
is	O
written	O
by	O
the	O
system	B-Application
administrator	I-Application
or	O
sometimes	O
by	O
an	O
operating	O
system	O
installation	O
program	O
.	O
</s>
<s>
However	O
,	O
some	O
administration	O
tools	O
can	O
automatically	O
build	O
and	O
edit	O
fstab	B-Protocol
,	O
or	O
act	O
as	O
graphical	O
editors	O
for	O
it	O
.	O
</s>
<s>
Modern	O
Linux	B-Application
systems	O
use	O
udev	B-Application
as	O
an	O
automounter	O
to	O
handle	O
the	O
hot	B-Device
swapping	I-Device
of	O
devices	O
(	O
such	O
as	O
MP3	O
players	O
or	O
digital	O
cameras	O
)	O
instead	O
of	O
relying	O
on	O
fstab	B-Protocol
.	O
</s>
<s>
Programs	O
such	O
as	O
pmount	O
allow	O
ordinary	O
users	O
to	O
mount	B-Application
and	O
unmount	B-Application
filesystems	B-Application
without	O
a	O
corresponding	O
fstab	B-Protocol
entry	O
;	O
traditional	B-Application
Unix	I-Application
has	O
always	O
allowed	O
privileged	O
users	O
(	O
the	O
root	B-Application
user	I-Application
and	O
users	O
in	O
the	O
wheel	B-Operating_System
group	I-Operating_System
)	O
to	O
mount	B-Application
or	O
unmount	B-Application
devices	O
without	O
a	O
corresponding	O
fstab	B-Protocol
entry	O
.	O
</s>
<s>
The	O
following	O
is	O
an	O
example	O
of	O
an	O
fstab	B-Protocol
file	O
on	O
a	O
typical	O
Linux	B-Application
system	O
.	O
</s>
<s>
The	O
order	O
of	O
records	O
in	O
fstab	B-Protocol
is	O
important	O
because	O
fsck(8 )	O
,	O
mount(8 )	O
,	O
and	O
umount(8 )	O
sequentially	O
iterate	O
through	O
fstab	B-Protocol
and	O
mount	B-Application
in	O
the	O
order	O
defined	O
.	O
</s>
<s>
device-spec	O
–	O
The	O
device	O
name	O
,	O
label	O
,	O
UUID	O
,	O
or	O
other	O
means	O
of	O
specifying	O
the	O
partition	B-Application
or	O
data	O
source	O
this	O
entry	O
refers	O
to	O
.	O
</s>
<s>
mount-point	O
–	O
Where	O
the	O
contents	O
of	O
the	O
device	O
may	O
be	O
accessed	O
after	O
mounting	B-Application
;	O
for	O
swap	B-Architecture
partitions	B-Application
or	O
files	O
,	O
this	O
is	O
set	O
to	O
none	O
.	O
</s>
<s>
fs-type	O
–	O
The	O
type	O
of	O
file	B-Application
system	I-Application
to	O
be	O
mounted	O
.	O
</s>
<s>
options	O
–	O
Options	O
describing	O
various	O
other	O
aspects	O
of	O
the	O
file	B-Application
system	I-Application
,	O
such	O
as	O
whether	O
it	O
is	O
automatically	O
mounted	O
at	O
boot	O
,	O
which	O
users	O
may	O
mount	B-Application
or	O
access	O
it	O
,	O
whether	O
it	O
may	O
be	O
written	O
to	O
or	O
only	O
read	O
from	O
,	O
its	O
size	O
,	O
and	O
so	O
forth	O
;	O
the	O
special	O
option	O
defaults	O
refers	O
to	O
a	O
pre-determined	O
set	O
of	O
options	O
depending	O
on	O
the	O
file	B-Application
system	I-Application
type	O
.	O
</s>
<s>
dump	B-Application
–	O
A	O
number	O
indicating	O
whether	O
and	O
how	O
often	O
the	O
file	B-Application
system	I-Application
should	O
be	O
backed	B-Protocol
up	I-Protocol
by	O
the	O
dump	B-Application
program	O
;	O
a	O
zero	O
indicates	O
the	O
file	B-Application
system	I-Application
will	O
never	O
be	O
automatically	O
backed	B-Protocol
up	I-Protocol
.	O
</s>
<s>
pass	O
–	O
A	O
number	O
indicating	O
the	O
order	O
in	O
which	O
the	O
fsck	B-Device
program	O
will	O
check	O
the	O
devices	O
for	O
errors	O
at	O
boot	O
time	O
:	O
</s>
<s>
With	O
the	O
auto	O
option	O
,	O
the	O
device	O
will	O
be	O
mounted	O
automatically	O
at	O
bootup	O
or	O
when	O
the	O
mount	B-Application
-a	O
command	O
is	O
issued	O
.	O
</s>
<s>
For	O
the	O
device	O
not	O
to	O
be	O
mounted	O
automatically	O
,	O
the	O
noauto	B-Protocol
option	O
is	O
used	O
in	O
/etc/fstab	B-Protocol
.	O
</s>
<s>
With	O
noauto	B-Protocol
,	O
the	O
device	O
can	O
be	O
only	O
mounted	O
explicitly	O
.	O
</s>
<s>
Controls	O
behavior	O
of	O
the	O
interpretation	O
of	O
block	B-General_Concept
special	O
devices	O
on	O
the	O
filesystem	B-Application
.	O
</s>
<s>
exec	O
lets	O
binaries	O
that	O
are	O
on	O
the	O
partition	B-Application
be	O
executed	O
,	O
whereas	O
noexec	O
is	O
the	O
opposite	O
.	O
</s>
<s>
noexec	O
might	O
be	O
useful	O
for	O
a	O
partition	B-Application
that	O
contains	O
no	O
binaries	O
,	O
like	O
/var	O
,	O
or	O
contains	O
binaries	O
the	O
user	O
may	O
not	O
want	O
to	O
execute	O
on	O
the	O
system	O
,	O
or	O
that	O
cannot	O
even	O
be	O
executed	O
on	O
the	O
system	O
,	O
as	O
might	O
be	O
the	O
case	O
of	O
a	O
Windows	O
partition	B-Application
.	O
</s>
<s>
Mount	B-Application
the	O
filesystem	B-Application
in	O
either	O
read	O
write	O
or	O
read	O
only	O
mode	O
.	O
</s>
<s>
Explicitly	O
defining	O
a	O
file	B-Application
system	I-Application
as	O
rw	O
can	O
alleviate	O
some	O
problems	O
in	O
file	B-Application
systems	I-Application
that	O
default	O
to	O
read	O
only	O
,	O
as	O
can	O
be	O
the	O
case	O
with	O
floppies	O
or	O
NTFS	B-Application
partitions	B-Application
.	O
</s>
<s>
How	O
the	O
input	O
and	O
output	O
to	O
the	O
filesystem	B-Application
should	O
be	O
done	O
.	O
</s>
<s>
Looking	O
at	O
the	O
example	O
fstab	B-Protocol
,	O
this	O
is	O
the	O
option	O
used	O
with	O
the	O
floppy	O
.	O
</s>
<s>
user	O
permits	O
any	O
user	O
to	O
mount	B-Application
the	O
filesystem	B-Application
.	O
</s>
<s>
If	O
nouser	O
is	O
specified	O
,	O
only	O
root	B-Application
can	O
mount	B-Application
the	O
filesystem	B-Application
.	O
</s>
<s>
If	O
users	O
is	O
specified	O
,	O
every	O
user	O
in	O
group	O
users	O
will	O
be	O
able	O
to	O
unmount	B-Application
the	O
volume	O
.	O
</s>
<s>
Default	O
settings	O
are	O
defined	O
per	O
file	B-Application
system	I-Application
at	O
the	O
file	B-Application
system	I-Application
level	O
.	O
</s>
<s>
For	O
ext3	B-Application
file	B-Application
systems	I-Application
these	O
can	O
be	O
set	O
with	O
the	O
tune2fs	O
command	O
.	O
</s>
<s>
The	O
normal	O
default	O
for	O
ext3	B-Application
file	B-Application
systems	I-Application
is	O
equivalent	O
to	O
rw	O
,	O
suid	O
,	O
dev	O
,	O
exec	O
,	O
auto	O
,	O
nouser	O
,	O
async	O
.	O
</s>
<s>
Modern	O
Red	O
Hat	O
based	O
systems	O
set	O
ACL	O
support	O
as	O
default	O
on	O
the	O
root	B-Application
file	B-Application
system	I-Application
but	O
not	O
on	O
user-created	O
ext3	B-Application
filesystems	I-Application
.	O
</s>
<s>
Some	O
file	B-Application
systems	I-Application
such	O
as	O
XFS	B-Application
enable	O
ACLs	O
by	O
default	O
.	O
</s>
<s>
Default	O
file	B-Application
system	I-Application
mount	B-Application
attributes	O
can	O
be	O
overridden	O
in	O
/etc/fstab	B-Protocol
.	O
</s>
<s>
Permit	O
the	O
owner	O
of	O
device	O
to	O
mount	B-Application
.	O
</s>
<s>
The	O
Unix	B-Application
stat	B-Language
structure	O
records	O
when	O
files	O
are	O
last	O
accessed	O
(	O
atime	O
)	O
,	O
modified	O
(	O
mtime	O
)	O
,	O
and	O
changed	O
(	O
ctime	O
)	O
.	O
</s>
<s>
However	O
,	O
atime	O
is	O
used	O
by	O
some	O
applications	O
and	O
desired	O
by	O
some	O
users	O
,	O
and	O
thus	O
is	O
configurable	O
as	O
atime	O
(	O
update	O
on	O
access	O
)	O
,	O
noatime	O
(	O
do	O
not	O
update	O
)	O
,	O
or	O
(	O
in	O
Linux	B-Application
)	O
relatime	O
(	O
update	O
atime	O
if	O
older	O
than	O
mtime	O
)	O
.	O
</s>
<s>
Through	O
Linux	B-Application
2.6.29	O
,	O
atime	O
was	O
the	O
default	O
;	O
as	O
of	O
2.6.30	O
,	O
relatime	O
is	O
the	O
default	O
.	O
</s>
<s>
There	O
are	O
many	O
options	O
for	O
the	O
specific	O
filesystems	B-Application
supported	O
by	O
mount	B-Application
.	O
</s>
<s>
The	O
full	O
list	O
may	O
be	O
found	O
in	O
the	O
documentation	O
for	O
mount	B-Application
.	O
</s>
<s>
Note	O
that	O
these	O
are	O
for	O
Linux	B-Application
;	O
traditional	O
Unix-like	O
systems	O
have	O
generally	O
provided	O
similar	O
functionality	O
but	O
with	O
slightly	O
different	O
syntax	O
or	O
forms	O
.	O
</s>
<s>
Sets	O
the	O
fsck	B-Device
checking	O
level	O
.	O
</s>
<s>
n	O
is	O
the	O
block	B-General_Concept
which	O
should	O
be	O
used	O
as	O
the	O
super-block	O
for	O
the	O
filesystem	B-Application
.	O
</s>
<s>
See	O
mount(8 )	O
.	O
</s>
<s>
Performs	O
DOS	O
<=>	O
UNIX	B-Application
text	O
file	O
conversions	O
automatically	O
.	O
</s>
<s>
See	O
mount(8 )	O
.	O
</s>
<s>
Linux	B-Application
filesystems	B-Application
have	O
a	O
larger	O
set	O
of	O
allowed	O
characters	O
in	O
filenames	O
.	O
</s>
<s>
windows_names	O
restricts	O
the	O
set	O
of	O
allowed	O
characters	O
for	O
the	O
volume	O
to	O
only	O
those	O
acceptable	O
by	O
Windows	O
;	O
though	O
FAT/NTFS	O
are	O
the	O
most	O
common	O
use	O
cases	O
,	O
this	O
feature	O
is	O
not	O
specifically	O
restricted	O
to	O
those	O
filesystem	B-Application
types	O
.	O
</s>
<s>
Sets	O
the	O
user	B-Application
identifier	I-Application
(	O
uid	B-Application
)	O
,	O
and	O
group	B-Application
identifier	I-Application
(	O
gid	B-Application
)	O
for	O
all	O
files	O
on	O
the	O
filesystem	B-Application
.	O
</s>
<s>
Controls	O
masking	O
of	O
filesystem	B-Application
nodes	O
.	O
</s>
<s>
More	O
detailed	O
information	O
about	O
the	O
fstab	B-Protocol
file	O
can	O
be	O
found	O
in	O
the	O
man	B-Protocol
page	I-Protocol
for	O
;	O
for	O
other	O
systems	O
see	O
below	O
.	O
</s>
<s>
ip	O
is	O
a	O
valid	O
IP	B-Protocol
address	I-Protocol
.	O
</s>
