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5.3.7.
ABORT (06h)
This message is sent from the initiator to the target to clear the present operation. All pending data and status from
the affected logical unit is cleared, and the target goes to the BUS FREE phase. This message can be sent to a
logical unit that is not currently performing an operation for the initiator.
A transaction which has not yet been acknowledged with a good Status byte will cause the transaction to be aborted.
If a transaction has already been acknowledged, the abort will force a Write of any pending data. The device will
proceed directly to BUS FREE state.
MESSAGE REJECT (07h)
5.3.8.
This message is sent from either the initiator or target to indicate that the last message it received was inappropriate
or has not been implemented.
In order to indicate its intentions of sending this message, the initiator asserts the ATN signal prior to its release of
ACK for the REQ ACK handshake of the message that is to be rejected. Message Reject is issued in response to any
messages which the unit considers to be illegal or not supported. The illegal message will cause the current
command to be aborted and the unit will enter the status phase reporting CHECK CONDITION with the sense key
set to COMMAND ABORTED.
When received as a target, if the unit was previously in Message In phase (i.e.: sending messages to the host) then
MESSAGE REJECT will cause the unit to go straight to the Status phase with a CHECK CONDITION status and a
sense key of COMMAND ABORTED. If the unit was not previously in Message In phase then MESSAGE REJECT
will be handled as an illegal message.
If the initiator sends MESSAGE REJECT message in response to the units DISCONNECT message, the unit will
disable disconnects for the rest of the nexus and continue.
NO OPERATION (08h)
5.3.9.
This message is sent by an initiator in response to a target's request for a message when the initiator does not
currently have any other valid message to send. This message is accepted when the drive is acting as a target, and
may be sent when it is an initiator. When a NO-OP is received during any phase, the unit will continue as though
nothing had happened.
5.3.10. MESSAGE PARITY ERROR (09h)
This message is sent from the initiator to the target to indicate that one or more bytes in the last message it received
had a parity error.
To indicate its intentions of sending this message, the initiator will send the ATN signal prior to its release of ACK for
the REQ/ACK handshake of the message that has the parity error. This provides an interlock so that the target can
determine which message has the parity error.
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.
5.3.11. BUS DEVICE RESET (0Ch)
This message is sent from an initiator to direct a target to clear all current commands. Upon recognizing this
message, the currently executing command will be aborted and the drive will proceed to the BUS FREE state. The
drive will then execute a hard reset which will leave the drive in a state as if it had been power-cycled. All data in the
buffer will be written to tape before the reset is performed.
A BUS DEVICE RESET message should be used to reset the drive, rather than a hard reset, as this will only reset
the drive rather than all the devices on the bus.
Due to the catastrophic nature of this command, it should be used cautiously in a multiple initiator system.
SONY AIT-1 Turbo drive SDX-450V series Ver.1.0
5.SCSI Interface
5-9
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