IBM T200F manual Multi-initiator Support, Status Codes, Description Value When returned

Multi-initiator Support

SCSI-attached drives support a maximum of two initiators on the same bus.

Fibre-Channel-attached drives support a minimum of two initiators.

The drive supports untagged queuing when operating with multiple initiators. If a command from one initiator is being processed when a command other than INQUIRY, REPORT LUNs, REQUEST SENSE, and TEST UNIT READY is received from a second initiator, the new command is queued. Commands (other than INQUIRY, REPORT LUNs, REQUEST SENSE, and TEST UNIT READY) from different initiators are always executed in strict order of receipt. For drives with a SCSI interface, if the queue is full or disconnect privilege is not granted in the new command, the drive reports busy status.

The INQUIRY, REPORT LUNs, REQUEST SENSE, and TEST UNIT READY commands are always processed immediately, irrespective of whether a command from another initiator is being processed.

The drive maintains sense data for the supported number of initiators. On Fibre-Channel-attached drives, if an additional initiator connects to the drive, the drive erases all sense data for the initiator that least recently connected before processing the command for the new initiator. See “Sense Data Management” on page 87 for more details of sense data management.

Status Codes

Table 111. Status Codes

Description	Value	When returned
Good	00h	The command completed without problems.
Check Condition	02h	A problem occurred during command execution. The
		sense data should be examined to determine the nature of
		the problem.
Condition Met	04h	This status is never returned, since no supported
		commands generate this status.
Busy	08h	The drive is unable to accept the command at this time.
		This status is returned during the power-on sequence or if
		there are commands from too many initiators outstanding.
		(See “Multi-initiator Support” on page 96.) It is also
		returned when commands are issued without Disconnect
		Privilege and when another command is in progress.
Intermediate	10h	This status is never returned, since Linked commands are
		not supported.
Intermediate	14h	This status is never returned, since no supported
Condition met		commands generate this status.
Reservation Conflict	18h	This status is returned if the drive is reserved for an
		initiator other than the one sending the command.
Command Terminated	22h	This status is never returned, since the terminate I/O
		process message is not supported.
Queue Full	28h	This status is never returned, since tagged queuing is not
		supported.

96Ultrium Internal Tape Drive and 3580 Ultrium Tape Drive: SCSI Reference