Scanner Interface
Upon receiving the MESSAGE REJECT message, this scanner takes action as shown in the following table.
Message rejected | Action |
|
|
COMMAND COMPLETE | Moves to the BUS FREE phase. |
| (It is not assumed as an error.) |
|
|
MESSAGE REJECT | Responds the CHECK CONDITION status |
|
|
DISCONNECT | The command execution is continued with |
| connecting the SCSI bus (without disconnecting). |
|
|
SAVE DATA POINTER | The command execution is continued with |
| connecting the SCSI bus (without disconnecting). |
|
|
IDENTIFY | When this message is issued for reconnection, the |
| command is terminated with an error. In this case, |
| the reconnection for the command is not performed |
|
|
RESTORE POINTERS | The error recover is interrupted and the CHECK |
| CONDITION status is responded. |
|
|
SYNCHRONOUS DATA | The command execution is continued in |
TRANSFER REQUEST | Asynchronous transfer mode. |
|
|
No message issued | Moves to the BUS FREE phase |
|
|
(5)NO OPERATION (X’08’) : MESSAGE OUT phase (initiator → target)
This message is issued in response to a message request from the target and indicates that the initiator does not have a valid message.
The initiator does not intend to issue another message by activating ATN before it deactivates the ACK of the NO OPERATION message.
(6)MESSAGE PARITY ERROR (X’09’) : MESSAGE OUT phase (initiator → target)
This message indicates that the initiator detected a parity error in the message received. The target resends only that message.
The initiator does not intend to issue another message by activating ATN before it deactivates the ACK of the MESSAGE PARITY ERROR message.
Upon receiving the MESSAGE PARITY ERROR message, this scanner takes action as shown in the following table.
Phase when ATN is | Action |
detected |
|
|
|
MESSAGE IN | Moves to the MESSAGE IN phase and resends the |
| message (*1) |
|
|
Other | Moves to the BUS FREE phase |
|
|
*1 This scanner retries three times with the message in the MESSAGE IN phase. If the third retry fails, this scanner immediately moves to the BUS FREE phase.
Appendix