Maxtor 10K V manual Status/Error Reporting, Linked Commands, Status Definition Meaning

5.3Status/Error Reporting

SCSI message-level errors are communicated by messages that are defined specifically for that purpose. SCSI command-level errors are communicated by a status that is returned by the drive during the STATUS phase. This phase occurs at the end of each command, unless the command is terminated by one of the following events:

•ABORT TASK SET message

•ABORT TASK message

•TARGET RESET message

•CLEAR QUEUE message

•Unexpected disconnect

The status code is contained in bits 1 through 5 of the status byte. Bits 0, 6, and 7 are reserved. Table 5-6 describes the status codes returned by the drive.

		Table 5-6Status Codes
Status	Definition		Meaning
00h	GOOD		The drive successfully completed the command.
02h	CHECK CONDITION		An Auto Contingent Allegiance (ACA) condition occurred.
			The drive cannot service the command at the moment, and its Com-
			mand Descriptor Block has been discarded. The initiator can retry the
			command at a later time. This status is returned when:
			• A non-tagged command is received and the logical unit's com-
			mand queue is full (all internal command buffers are in use).
08h	BUSY		• A disconnect privilege was not granted in the IDENTIFY mes-
			sage of a queue-tagged I/O process (Parallel SCSI).
			• A disconnect privilege was not granted in the IDENTIFY mes-
			sage of a non-tagged I/O process and a command from another
			initiator is currently active (Parallel SCSI)
			• A command is received while an auto-contingent allegiance
			condition exists for another initiator.
			This status is returned for every command (except the last) in a series
			of linked commands that was successfully completed. However, if the
10h	INTERMEDIATE		command is terminated with other that GOOD status (such as
			CHECK CONDITION, RESERVATION CONFLICT, OR
			BUSY), the INTERMEDIATE status is not returned and the series of
			linked commands and the task is ended.
18h	RESERVATION CONFLICT		Another initiator has reserved the drive. (This status is never returned
			for INQUIRY or REQUEST SENSE commands.)
			The drive cannot service the command at the moment, and its Com-
			mand Descriptor Block has been discarded. (Returned for a tagged
28h	TASK SET FULL		command when all of the drive's internal command buffers are in use,
			or when a host sends a tagged command while an Auto Contingent
			Allegiance condition is pending for that initiator)

5.4Linked Commands

An I/O Process (task) may contain multiple commands that are linked together. The initiator communicates this condition of linked (or unlinked) commands by setting (or clearing) the Link bit of the Command Descriptor Block’s control word. A linked

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