SCSI Description

￿￿￿%QPFKVK#WVQAuto￿%QPContingentVKPIGPV￿Allegiance#NNGIKCPEGcondition￿%QPFKVKQP(ACA)￿CPFis the￿%QPVKPIGPVSCSI-3 term￿for#NNGIKCPEGthe condition￿of the drive immediately after it returns a CHECK CONDITION status code. While it is in this condition, the drive:

Keeps the status information (sense data) that characterizes the nature of, and the reason for, the command's failure.

Suspends execution of all commands that were queued behind the command that failed (includes commands from all initiators, tagged or untagged).

Discards and returns BUSY status for both tagged and untagged drive access commands from other initiators.

The Auto Contingent Allegiance condition remains in effect until cleared by one of the following:

TARGET RESET message received from any initiator

ABORT TASK SET message received from the allegianced initiator

Subsequent command received from the allegianced initiator

After receipt of an ABORT TASK SET message from the “allegianced” initiator, the drive clears any queued command sourced by that initiator and processes the remaining queued commands.

For Parallel SCSI, as its first action following receipt of the CHECK CONDITION status code, the initiator sends a REQUEST SENSE command to retrieve the sense data. Any other command from the initiator causes the drive to set the sense key to NO SENSE and the additional sense code to NO ADDITIONAL SENSE INFORMATION. These actions happen prior to resuming execution of queued commands, or, if there are no commands queued, before processing a new command.

Also for Parallel SCSI, after receipt of the REQUEST SENSE command or any other command from the “allegianced” initiator, the drive resumes processing of the queued commands in the normal manner if the QErr bit in the MODE SELECT Control Mode page is set to 0, its default value. If the value of QErr is 1, the drive aborts all queued commands and generates a Unit Attention condition for initiators with commands in the queue. A Unit Attention condition is not generated for the “allegianced” initiator if commands belonging to it are flushed from the queue.

Maxtor Atlas 10K III

5-7

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Maxtor 10K III manual Scsi Description