Sony SDX-800V/R User Manual
READ POSITION
6.Command Specification
SONY AIT-3Ex drive SDX-800V series Ver.1.1
6-75
6.16. READ POSITION 34h
Bit
Byte
7 6 5 4 3 2 1 0
0
Operation Code (34h)
1
Obsolete Reserved
TCLP
LONG
BT
2
Reserved
3
Reserved
4
Reserved
5
Reserved
6
Reserved
7
Reserved
8
Reserved
9
Control
The READ POSITION command reports the current position of the logical unit. No medium movement shall occur as
a result of the command. The position is given in two parts:
a result of the command. The position is given in two parts:
TCLP: The Total Current Logical Position (TCLP) bit of ONE indicates the drive shall return data specifying the
partition, file, and set number with the current logical position. The TCLP bit of ZERO indicates the drive shall return
data specifying the first and last block location with the number of bytes and blocks in buffer.
LONG: The Long Format (LONG) bit of ONE indicates the drive shall return 32 bytes of data. The LONG bit of ZERO
indicates the drive shall return 20 bytes of data.
The LONG bit and the TCLP bit shall be equal. If the LONG and TCLP bits are not equal, or if both the LONG and the
Block Address Type (BT) bits are ONE, the command is rejected with a CHECK CONDITION status and an
ILLEGAL REQUEST sense key set.
BT: The Block Address type (BT) bit controls the content of the short format data. The BT bit if one requests the drive
to return its current First Block Location shall include data block only. The BT bit of ZERO requests the drive to return
the First Block Location are a SCSI Logical Block Address (data blocks, File-marks and Save Set Marks are
counted.)
counted.)
Table 6-75: READ POSITION Data Format, short form
Bit
Byte
7 6 5 4 3 2 1 0
0
BOP EOP
Reserved
BPU
Reserved
1
Partition Number
2
Reserved
3
Reserved
4
(MSB)
First Block Location
7
(LSB)
8
(MSB)
Last Block Location
11
(LSB)
12
Reserved
13
(MSB)
Number of Blocks in Buffer
15
(LSB)
16
(MSB)
Number of Bytes in Buffer (00 00 00 00h)
19
(LSB)
BOP: A Beginning Of Partition (BOP) bit of one indicates that the logical unit is at the beginning-of-partition in the
current partition. A BOP bit of ZERO indicates that the current logical position is not at the beginning-of-partition.
EOP: An End Of Partition (EOP) bit of one indicates that the logical unit is positioned between early-warning and
end-of-partition in the current partition. An EOP bit of ZERO indicates that the current logical position is not between
early-warning and end-of-partition. Note that this bit is mutually exclusive with the BOP bit.
early-warning and end-of-partition. Note that this bit is mutually exclusive with the BOP bit.