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5.SCSI Interface
SAVE DATA POINTER (02h)
5.3.3.
This message is sent from a target to the initiator at the end of a Data Phase to request that the initiator save a copy
of the present active data pointer for the currently attached logical unit. The unit will accept this message when in the
initiator mode. As a target, it will send this message prior to a disconnect. When received as a target, it will be
handled as an illegal message, the unit will return MESSAGE REJECT and will enter the status phase reporting
CHECK CONDITION with the sense key set to COMMAND ABORTED.
RESTORE POINTERS (03h)
5.3.4.
This message is sent from a target to direct the initiator to restore the most recently saved pointers for the currently
attached logical unit to the active state. Pointers to the command, data, and status locations for the logical unit will be
restored to the active pointers. Command and status pointers will be restored to the beginning of the present
command and status areas. The data pointer will be restored to the value at the beginning of the data area in the
absence of a SAVE DATA POINTER message or to the value at the point at which the last SAVE DATA POINTER
message occurred for that logical unit.
The unit send a RESTORE POINTERS message. Rather, it relies on the implicit restore pointers inherent in a
re-selection.
When acting as initiator, the unit will accept a RESTORE POINTERS message before resending a previously
unsuccessful status or data transfer. It doesn't send a RESTORE POINTERS for re-selection but relies on the
implicit restore pointers in re-selection.
When received as a target, it will be handled as an illegal message; the unit will return MESSAGE REJECT and will
continue.
DISCONNECT (04h)
5.3.5.
This message is sent from a target to inform an initiator that the present physical path is going to be broken (the
target plans to disconnect by releasing BSY). Later, reelection will be required in order to complete the current
operation.
Note: The initiator detects a catastrophic error condition when the BUS FREE phase occurs (other than as result of
a RESET condition) without first receiving a DISCONNECT or COMMAND COMPLETE message. If the target
intentionally creates this condition, the target clears the current command. This message does not cause the initiator
to save the data pointer.
The unit will support this message as an initiator. As a target, the unit supports this message and will disconnect if
allowed by the initiator.
When received as a target, it will be handled as an illegal message; the unit will return MESSAGE REJECT and will
continue.
INITIATOR DETECTED ERROR (05h)
5.3.6.
This message is sent from an initiator to inform a target that an error (e.g.: parity error) has occurred that does not
prevent the target from re-trying the operation. At this point, present pointer integrity is not assured. A RESTORE
POINTERS message or a disconnect followed by a re-selection, will cause the pointers to be restored to their
previously defined state.
This message will not be sent by the drive, when the drive is acting as an initiator. When received as a target the unit
will enter the status phase reporting CHECK CONDITION with the sense key set to COMMAND ABORTED.
5-8
SONY AIT-E Turbo drive SDX-250V series Ver.1.0
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