Read Position 34H - Sony AIT-SDX550 Product Specifications Manual

6.Command Specification

6.15. READ POSITION 34h

Bit 7
Byte
0
1 Logical Unit Number
2
3
4
5
6
7
8
9 Unused (00b)
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:
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.)
Bit 7
Byte
0 BOP
1
2
3
4 (MSB)
7
8 (MSB)
11
12
13 (MSB)
15
16 (MSB)
19
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.
6-72
6 5
Operation Code (34h)
Table 6-61: READ POSITION Data Format, short form
6 5
EOP Reserved
First Block Location
Last Block Location
Number of Blocks in Buffer
Number of Bytes in Buffer (00 00 00 00h)
4 3
Reserved TCLP
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
4 3
BPU
Partition Number
Reserved
Reserved
Reserved
SONY AIT-2 Turbo drive SDX-550V series Ver.1.0
READ POSITION
2 1 0
LONG BT
Flag Link
2 1 0
Reserved
(LSB)
(LSB)
(LSB)
(LSB)