Refer to Queue State for details on the queue behavior a CDM can expect for a device.
A CDM deals with information it receives back from the HAM in differing ways, depending on the type of device that is registered.
If the I/O request of a direct access device (such as a hard drive) fails, the queue is automatically restarted by the CDM.
If the I/O request of a sequential access device (such as a tape or WORM) fails, the queue is frozen by the HAM and cannot be restarted by the CDM. It is the responsibility of the NLM application to restart the queue or abort the request. The CDM can query the device to get more extensive error information.