Seagate Ultra 320 Abort Task SET, Clear ACA, Clear Task SET, Logical Unit Reset, Target Reset

4.5.3ABORT TASK SET

The ABORT TASK SET message is defined in the SCSI Architecture Model-4 standard. In addition to the requirements in the SCSI Architecture Model-4 standard the target shall go to the BUS FREE phase following the successful receipt of the ABORT TASK SET message.

If only an I_T nexus has been established, the target shall switch to a BUS FREE phase. No status or message shall be sent for the current task and no pending data, status, or tasks are affected.

Note. The ABORT TASK SET message in the case of only an I_T nexus is useful to an initiator that is not able to send an Identify message through to the target due to parity errors and just needs to end the current task or task management function. It is not an error to issue this message to an I_T_L nexus that does not have any pending or current tasks.

4.5.4CLEAR ACA

The CLEAR ACA message is defined in the SCSI Architecture Model-4 standard.

The CLEAR ACA message shall only be sent by an initiator during an initial connection. If the target receives the CLEAR ACA message at any other time the target shall switch to a Message In phase and issue a MES- SAGE REJECT message. The target shall then continue processing the task that was in process when the CLEAR ACA message was received.

On receipt of a CLEAR ACA message, the task manager, in addition to clearing the ACA condition, shall go to the BUS FREE phase following the successful receipt of the CLEAR ACA message.

It is not an error to issue a CLEAR ACA message when no ACA condition is in effect.

4.5.5CLEAR TASK SET

The CLEAR TASK SET message is defined in the SCSI Architecture Model-4 standard.

In addition to the requirements in the SCSI Architecture Model-4 standard, the target shall go to the BUS FREE phase following the successful receipt of the CLEAR TASK SET message.

4.5.6LOGICAL UNIT RESET

The LOGICAL UNIT RESET message is defined in the SCSI Architecture Model-4 standard.

Receipt of the LOGICAL UNIT RESET message after an I_T_L nexus has been astablished is a logical unit reset event as defined in the SCSI Architecture Model-4 standard.

In addition to the requirements in the SCSI Architecture Model-4 standard, the target shall go to the BUS FREE phase following the successful receipt of the LOGICAL UNIT RESET message.

4.5.7TARGET RESET

The TARGET RESET message is defined in the SCSI Architecture Model-4 standard.

In addition to the requirements in the SCSI Architecture Model-4 standard, the target shall go to the BUS FREE phase following the successful receipt of the TARGET RESET message.

106 Parallel SCSI Interface Product Manual, Rev. A