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SCSI Commands

Quantum DLT 4000 Tape Drive 5-125

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 5–62 READ POSITION Command Descriptor Block - Data Format

Table 5–60 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.

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Quantum DLT 4000 Handbuch Seite 225