xref: /illumos-gate/usr/src/man/man4fs/dev.4fs (revision ddb365bfc9e868ad24ccdcb0dc91af18b10df082)
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20.Dd March 10, 2023
21.Dt DEV 4FS
22.Os
23.Sh NAME
24.Nm dev
25.Nd Device name file system
26.Sh DESCRIPTION
27The
28.Nm
29filesystem manages the name spaces of devices in the operating system.
30The global zone's instance of the
31.Nm
32filesystem is mounted during boot on
33.Pa /dev .
34This filesystem is colloquially called
35.Sq sdev
36as a way to distinguish it from the
37.Xr devfs 4FS
38filesystem mounted at
39.Pa /devices .
40.Pp
41A subdirectory under
42.Pa /dev
43may have unique operational semantics.
44Most of the common device names under
45.Pa /dev
46are created automatically by
47.Xr devfsadm 8
48Others, such as
49.Pa /dev/pts ,
50.Pa /dev/net ,
51and
52.Pa /dev/zvol
53are dynamic and reflect the operational state of the system.
54You can manually generate device names for newly attached hardware by invoking
55.Xr devfsadm 8
56or implicitly, by indirectly causing a lookup or readdir operation in the
57filesystem to occur.
58For example, you can discover a disk that was attached when the system was
59powered down (and generate a name for that device) by invoking
60.Xr format 8 .
61.Pp
62In a non-global zone, the
63.Nm
64filesystem is also mounted at
65.Pa /dev ;
66however, it is generally speaking read-only.
67Unlike in the global zone, a privileged user in a non-global zone cannot create
68directories or files, directories, or other objects within the filesystem.
69.Sh FILES
70.Bl -tag -width Pa
71.It Pa /dev
72Mount point for the
73.Nm
74filesystem in the global zone and non-global zones.
75.El
76.Sh SEE ALSO
77.Xr devfs 4FS ,
78.Xr devfsadm 8 ,
79.Xr format 8
80.Sh NOTES
81The global
82.Pa /dev
83instance cannot be unmounted.
84