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

Devices file system

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.

Mount point for devfs file system in the global zone.

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

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.

November 29, 2021 OmniOS