Sony DDS-4 Product Description Manual page 152

6. COMMAND SPECIFICATION
Combined Header and Data Mode
- in this mode, the test data to be transferred must be preceded by a four-byte header. The four-byte header consists
of all reserved bytes. The Parameters List Length specifies the maximum number of bytes that will be transferred
during the DATA OUT phase. This number includes four bytes of header, so the data length to be stored in the
buffer is transfer length minus four. The initiator should ensure that the transfer length is not greater than four plus
the available length that is returned in the header of the READ BUFFER command.
Data Mode
- in this mode, the DATA OUT phase contains only buffer test data.
Buffer ID:
The drive supports Buffer ID field of zero and one. If the Buffer ID is set to ZERO, the initiator has access to the I/
F Buffer. If the Buffer ID is set to ONE, the initiator has access to the Group Buffer.
Buffer Offset:
The buffer offset field contains the byte offset within the specified buffer from which data shall be transferred from.
The initiator should conform to the offset boundary requirements returned in the WRITE BUFFER descriptor. If
the target is unable to accept the specified buffer offset, it shall return CHECK CONDITION status, shall set the
Sense Key to ILLEGAL REQUEST, and set the Additional Sense Code to ILLEGAL FIELD IN CDB.
Parameter List Length:
specifies the maximum number of bytes that will be transferred during the DATA OUT phase. The initiator should
attempt to ensure that the Parameter List Length does not exceed the buffer capacity. If this does occur, the drive
returns a CHECK CONDITION status with an ILLEGAL REQUEST sense key set. The capacity of the buffer can
be determined from the Buffer capacity field in the READ BUFFER descriptor. The Parameter List Length must be
greater than four (except in data only mode), else the drive will return a CHECK CONDITION status with an
ILLEGAL REQUEST sense key set.
Mode Description
000b Write combined header and data
010b Write data
Table 6-56: WRITE BUFFER Mode Field
SONY SDT-10000/SDT-11000 DDS Tape Drive
WRITE BUFFER
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