Specifications

ATAPI For Streaming Tape QIC-157 Rev B
49
6.8.4. LOCATE Command
LOCATE command causes the Device to position to the specified block address in a specified
partition. Upon completion, the logical position shall be before the specified location. Prior to
performing the locate operation, the Device shall ensure that all buffered data, and filemarks have
been transferred to the medium.
Table 6-14 Locate Command
Bit
Byte
7 6 5 4 3 2 1 0
0 Operation code (2Bh)
1 Reserved 0 (BT) CP Reserved
(Immed)
2 Reserved
3 (MSB)
4 Block Address
5
6 (LSB)
7 Reserved
8 - Partition -
9 Reserved
10 Reserved
11 Reserved
The Block Type (BT) bit of zero indicates the value in the block address field shall be interpreted as a
sequential Logical Block Address with block zero originating at the beginning-of-partition.
[Implementor's Note: If the BT bit is set to one, it will be ignored, and the Block Address field will be interpreted as a
Logical Block Address.]
A Change Partition (CP) bit of one indicates that a change to the partition specified in the partition
field is to occur prior to positioning to the block specified in the block address field. A CP bit of zero
indicates no partition change is to be made and the partition field is to be ignored.
The Block Address field specifies the block address to which the Device shall position the medium.
The Partition field specifies which partition to select if the CP bit is one.
Table 6-15 Recommended Sense Key, ASC and ASCQ for LOCATE Errors
Sense Key ASC ASCQ Description of Error
02 04 00 NOT READY, CAUSE NOT REPORTABLE
02 3A 00 MEDIUM NOT PRESENT
04 15 00 RANDOM POSITIONING ERROR
05 20 00 INVALID COMMAND OPERATION CODE
05 24 00 INVALID FIELD IN COMMAND PACKET
06 28 00 NOT READY TO READY TRANSITION
06 29 00 POWER ON, RESET, OR ATAPI SOFT RESET OCCURRED
06 2A 01 MODE PARAMETERS CHANGED