Sony DDS-4, Product Description Manual

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5 - 5 SONY SDT-10000/SDT-11000 DDS Tape Drive
5. SCSI INTERFACE
5. 3 MESSAGE SPECIFICATION
This section includes all SCSI messages. Both supported and non-supported messages are listed. Elements of this
section come from section 5, Logical Characteristics, of the SCSI standard.
The message system allows communication between an initiator and a target for the purpose of physical path manage-
ment. The table below lists the Messages supported by the SDT-10000/SDT-11000.
Code Description Direction
In Out
00 COMMAND COMPLETE *
01 EXTENDED MESSAGE (Note 1) * *
02 SAVE DATA POINTER *
03 RESTORE POINTERS *
04 DISCONNECT *
05 INITIATOR DETECTED ERROR *
06 ABORT *
07 MESSAGE REJECT * *
08 NO OPERATION *
09 MESSAGE PARITY ERROR *
0C BUS DEVICE RESET *
23 IGNORE WIDE RESIDUE *
80- FF IDENTIFY * *
Table 5-2: Message Descriptions
Note: The SDT-10000/SDT-11000 supports the Synchronous Data Transfer Request Extended Message.
5. 3. 1 COMMAND COMPLETE (00h)
This message is sent from a target to an initiator to indicate that the execution of a command has completed and valid
status has been sent to the initiator. After successfully sending this message, the target goes to the BUS FREE phase by
releasing BSY.
When received as a target, it will be handled as an illegal message, the unit will return MESSAGE REJECT and will
continue.
5. 3. 2 EXTENDED MESSAGE (01h)
5. 3. 2. 1 SYNCHRONOUS DATA TRANSFER REQUEST
This is sent by either the initiator or the target as the first byte of a multiple-byte message. When acting as an initiator,
the unit will not send any Extended Messages. No Vendor Unique codes are implemented and only the Synchronous
Data Transfer Request code is supported. Any other message code is handled as an illegal message; the unit will return
MESSAGE REJECT and will continue. A Synchronous Data Transfer Request message has the following format:
Byte Value Description
0 01h Extended message
1 03h Extended message length
2 01h SYNCHRONOUS DATA TRANSFER REQUEST code
3 m Transfer period (m times 4 nanoseconds)
4 x REQ/ACK offset
Table 5-3: Synchronous Data Transfer Request