Quantum DLTtape DLT 7000, Product Manual

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SCSI Commands
Quantum DLT 7000 Tape System 5-137
5.15 READ POSITION COMMAND (34h)
The READ POSITION command is used to read a position identifier or SCSI Logical
Block Address (LBA). The LOCATE command uses this identifier to position back to
this same logical position in a high-performance fashion.
Bit
Byte
7 6 5 4 3 2 1 0
0 Operation Code (34h)
1 Logical Unit Number Reserved BT
2 - 8 Reserved
9 Unused Reserved Flag Link
Figure 5–67 READ POSITION Command Descriptor Block - Data Format
Table 5–65 READ POSITION Command Descriptor Block - Field Descriptions
Field Name Description
BT Block Type. This bit indicates how the position is to be interpreted. Since the
tape drive uses the same logical block regardless of the setting of this bit, the
setting is ignored. The logical block address values include all recorded objects:
blocks and filemarks.
NOTE
The drive returns CHECK CONDITION with UNIT NOT READY sense
key with the READ POSITION command if the media is not ready to
be accessed.