Device states
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 is configured 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.
Some devices, in particular TCP/IP pseudo-devices, need the stopped state.