DEVFS(4FS) File Systems DEVFS(4FS)

NAME

devfs - Devices file system

DESCRIPTION

The devfs filesystem manages a name space of all devices in the
operating environment and is mounted during boot on the /devices name
space.

The /devices name space is dynamic and reflects the current state of
accessible devices. The names of all attached device instances are
present under /devices.

The content under /devices is under the exclusive control of the devfs
filesystem and cannot be changed.

The system may be configured to include a device in one of two ways:

1. By means of dynamic reconfiguration (DR), using, for example,
cfgadm(8). Several different hardware buses such as PCIe and USB
automatically discover and enumerate devices that they encounter.

2. For devices driven by driver.conf(5) enumeration, edit the
driver.conf file to add a new entry, then use update_drv(8) to
cause the system to re-read the driver.conf file and thereby
enumerate the instance.

The device may be attached through a number of system calls and
programs, including open(2), stat(2), and ls(1). During device attach,
the device driver typically creates minor nodes corresponding to the
device via ddi_create_minor_node(9F). If the attach is successful, one
or more minor nodes referring to the device are created under /devices.

Operations like mknod(2), mkdir(2), and creat(2) are not supported in
/devices.

This file system is not present in a non-global zone.

FILES

/devices Mount point for devfs file system in
the global zone.

SEE ALSO

vfstab(5), devfsadm(8), attach(9E)

NOTES

The /devices name space cannot be unmounted.

All content at or below the /devices name space is an implementation
artifact and subject to incompatible change or removal without
notification. Generally, user programs should leverage the device name
space under /dev.

illumos November 29, 2021 illumos