User's Guide

Chapter 3 Emulated DLT7000 SCSI Commands

Read Position (34h)

238 Quantum DX-Series Software Interface Guide

Read Position (34h) 3

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.

Table 188 READ

POSITION Command

Descriptor Block -

Data Format

Bit/Byte 7 6 5 4 3 2 1 0

2-8

Table 189 READ

POSITION Command

Descriptor Block -

Field Descriptions

Data from READ POSITION takes the following format:

Offset Boundaries (34h)

Logical Unit Number Reserved BT

Reserved

Unused Reserved

Flag (0) Link (0)

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.