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Serial Attached SCSI (SAS) Interface
The initial read DATA frame for a given command shall set the DATA OFFSET
field to zero. If any additional read DATA frames are required, the DATA
OFFSET field shall be set to the value of the previous read DATA frame's data
offset plus the previous read DATA frame's data length.
The initial write DATA frame for a given command shall set the DATA OFFSET
field to zero. If any additional write DATA frames are required, the DATA
OFFSET field shall be set to the value of the previous write DATA frame's data
offset plus the previous write DATA frame's data length.
When a drive receives a write DATA frame, the following items are checked:
•
HASHED DESTINATION SAS ADDRESS field
When this field contains a value different from the Hashed SAS address of
the drive, the drive sends the ACK and CREDIT_BLOCKED primitives, and
discards the DATA frame.
•
HASHED SOURCE SAS ADDRESS field
When this field contains a value different from the SOURCE SAS
ADDRESS field of the OPEN frame, the drive sends the
CREDIT_BLOCKED primitive, and discards the DATA frame.
•
CRC field
When a CRC error is detected, the drive sends the NAK primitive, and
discards the DATA frame. At this time, the SENSE DATA for
INFORMATION UNIT iuCRC ERROR DETECTED is reported.
•
Frame length
When the IU length is greater than 1024 bytes, the drive discards the DATA
frame. At this time, the SENSE DATA for INFORMATION UNIT TOO
LONG is reported.
•
TAG field
When a DATA frame in which the same value as that set in the TARGET
PORT TRANSFER TAG field of the XFER_RDY frame is received, but the
tag is different from the one of the XFER_RDY frame, the drive sends the
ACK primitive and CREDIT_BLOCKED primitive, and discards the DATA
frame.
•
TARGET PORT TRANSFER TAG (TPTT) field
When a DATA frame with the TPTT field that does not match with the TPTT
field of the XFER_RDY frame is received, the drive sends the ACK primitive
and CREDIT_BLOCKED primitive, and discards the DATA frame. At this
time, after temporarily closing the connection, the drive re-opens a
connection and sends the SENSE DATA for TARGET PORT TRANSFER
TAG RECEIVED.
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C141-C009
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