Sony SDX-800V/R Benutzerhandbuch

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6.Command Specification 
READ POSITION
 
6-76 
 
SONY AIT-3Ex drive SDX-800V series Ver.1.1 
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: reports the current partition number for the current logical position. 
First block location: indicates the Block Address associated with the current logical position. The value shall 
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: indicates the Block Address associated with the next block to be transferred from the buffer to 
the medium. The value shall 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 shall be equal to the value reported for the first block location. 
Number of Blocks in Buffer: 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.  
Table 6-76: READ POSITION Data Format, long form 
Bit 
Byte 
7 6 5 4 3 2 1 0 
BOP EOP 
Reserved 
MPU BPU 
Reserved 
Reserved 
Reserved 
Reserved 
(MSB) Partition 
Number 
 
  
(LSB) 
(MSB) Block 
Number 
 
15 
  
(LSB) 
16 
(MSB) File 
Number 
 
23 
  
(LSB) 
24 
(MSB) Set 
Number 
 
31 
  
(LSB) 
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 know 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.  Set-marks and File-marks count as one logical block each. 
File Number: File Number reports the number of file-marks between beginning-of -partition and the current logical 
position. 
Set Number: Set Number reports the number of set-marks between beginning –of-partition and the current logical 
position