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6.Command Specification
BPU: A Block Position Unknown (BPU) bit of one indicates that the First and Last Block Locations are not known
or cannot be obtained. A BPU bit of ZERO indicates that the First contains valid position information.
Partition Number: This field reports the current partition number for the current logical position. This drive does
not support multi partition.
First block location: This field indicates the Block Address associated with the current logical position. The value
will indicate the Block Address of the next data block to be transferred between the initiator and the target if a
READ or WRITE command is issued. See BT field for description of Logical Block Address. Note that the Logical
Block Address at BOT/P is 0.
Last block location: This field indicates the Block Address associated with the next block to be transferred from
the buffer to the medium. The value will indicate the Block Address of the next data block to be transferred
between the buffer and the medium. If the buffer does not contain a whole block of data or is empty, the value
reported for the last block location will be equal to the value reported for the first block location.
Number of Blocks in Buffer: This field indicates the number of data blocks in the buffer of the logical unit that
have not been written to the medium.
Number of Bytes in Buffer: This field is not supported and is always set to ZERO.
Bit
7
Byte
0
BOP
1
2
3
4
(MSB)
7
8
(MSB)
15
16
(MSB)
23
24
(MSB)
31
The BOP, EOP, and Partition Number are as defined in the READ POSITION data returned when the TCLP bit is
set to 0.
BPU: The Block Position Unknown (BPU) bit of ONE indicates the partition number or block number are not
known or accurate reporting is not currently available. The BPU bit of ZERO indicates the partition number and
block number fields contain valid position information.
MPU: The Mark Position Unknown (MPU) bit of ONE indicates the file number and set number are not known or
accurate reporting is not currently available. The MPU bit of ZERO indicates the File number and Set number
fields contain valid position information.
Block Number: Block Number reports the number of logical blocks between beginning-of-partition and current
logical position. Setmarks and Filemarks count as one logical block each.
File Number: File Number reports the number of Filemarks between beginning-of -partition and the current logical
position.
Set Number: Set Number reports the number of Setmarks between beginning –of-partition and the current logical
position.
6-74
Table 6-78: READ POSITION Data Format, long form
6
5
4
EOP
Reserved
Partition Number(0)
Block Number
3
2
MPU
BPU
Reserved
Reserved
Reserved
File Number
Set Number
SONY AIT-5 drive SDX-1100V series Ver.1.0
READ POSITION
1
0
Reserved
(LSB)
(LSB)
(LSB)
(LSB)
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