Chapter 3 Error Recovery; Error Conditions And Retry Procedure - Fujitsu MAN3184 SERIES Specifications

CHAPTER 3
This chapter describes the SCSI bus errors and their recovery by the IDD.
Note:
If a severe error has occurred, the IDD may switch the SCSI bus to the BUS FREE phase
without sending the DISCONNECT or TASK COMPLETE message to the INIT. In such
case, the IDD clears all information of the currently executing commands and does not report
the command completion (or reconnection) to the INIT.
If the SCSI bus is switched to the BUS FREE phase in a sequence other than the normal bus
sequence, the INIT shall consider that the currently executing command has terminated
abnormally. In such case, the IDD may or may not generate a sense data of this error.
However, the INIT should issue the REQUEST SENSE command to obtain the error
information.
3.1

Error Conditions and Retry Procedure

(1) MESSAGE OUT phase parity error
When the IDD detects a parity error of the SCSI bus during the MESSAGE OUT phase, it retries
the MESSAGE OUT phase up to 3 times. If the IDD fails to recover a parity error, it proceeds to
the next procedure. For details, see Section 1.6.9.
If the LUN is already identified, the IDD terminates the currently executing command with the
CHECK CONDITION status. At this time, the sense key/sense code of the sense data indicates the
"ABORTED COMMAND [=B]/SCSI parity error [=47-00]." If this happens after the status is
reported, the IDD enters the BUSS FREE phase and the same sense data is retained. The IDD
ignores the ATTENTION condition until it enters the BUS FREE phase. If the LUN is not
identified by the IDENTIFY message or the LUN field of CDB, the IDD does not generate the
sense data and enters the BUS FREE phase immediately.
ERROR RECOVERY
3.1 Error Conditions and Retry Procedure
3.2 Recovery Control
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