Abort (06H); Message Reject (07H); No Operation (08H); Message Parity Error (09H) - Sony DDS-4 Product Description Manual

5. SCSI INTERFACE

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.

5. 3. 8 MESSAGE REJECT (07h)

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 unit DISCONNECT message, the unit will disable
disconnects for the rest of the nexus and continue.

5. 3. 9 NO OPERATION (08h)

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. 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 received as a target, the unit will return MESSAGE REJECT and will
continue.

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 multi-initiator system.
5 - 10 SONY SDT-10000/SDT-11000 DDS Tape Drive