Devices that are connected to the system can be in one of four states.
Devices that are connected to the system can be in one of the following states:
Item
Description
Undefined
The device is unknown to the system.
Defined
Specific information about the device is recorded in the customized database, but it is unavailable to the system.
Available
A defined device is coupled to the operating system, or the defined device is configured.
Stopped
The device is unavailable but remains known by its device driver.
If a tty device and a printer alternately use the same tty connector, both a tty device and a printer are defined on the same parent and port in the device configuration database. Only one of these devices can be configured at a time. When the tty connector is configured, the printer specific setup information is retained until it isconfigured again. The device is not removed; it is in the defined state. Maintaining a device in defined state retains customized information for a device that is not currently in use, either before it is first made available or while it is temporarily removed from the system.
If a device driver exists for a device, the device can be made available through the device driver.
https://www.ibm.com/docs/en/aix/7.2?topic=nodes-device-states
