4-3.17 Read Position Command 34H; 4-3.17.1 Read Position Cdb Description; Table 4-70. Read Position Field Description - Fujitsu M2488 Product Manual

M2488 PRODUCT GUIDE
4-3.17 READ POSITION command 34h
The READ POSITION command causes 20 bytes to be sent from the target to the initiator. The 20
bytes are a report of the position of the tape unit and information about blocks stored in the buffer;
the format of this data is shown in paragraph 4-3.17.2 on page 4-76.
This command can be executed when no tape cartridge is loaded or when the tape unit is not ready.
No tape movement is initiated due to this command.
4-3.17.1 READ POSITION CDB Description
READ POSITION is a ten-byte command. The bytes are shown below and described in Table 4-
70. Common fields are described in paragraph 4-3.1 on page 4-4.
BYTES 7
0 0
1
2
3
4
5
6
7
8
9
Note: Changeable fields in the CDB are shaded.
BYTE BIT VALUE
0 0-7
1 0
April 1997
6 5 4
0 1 1
LUN
Reserved

Table 4-70. READ POSITION Field Description

34h Operation code.
The BT bit dictates the format of values reported in the First Block Loca-
tion and Last Block Location fields of the return data.
0 Values in First Block Location and Last Block Location are to be reported
as Logical block addresses. The first filemark or data block on tape is
assigned logical block address 0; logical block addresses increase by 1 for
each data block and filemark thereafter. The maximum Logical block
address is 3FFFEFh.
1 Values in First Block Location and Last Block Location are to be reported
as Device specific block addresses (also known as Block IDs). The format
of these device specific block addresses are shown in paragraph 4-3.17.3
on page 4-78.
CG00000-011503 REV. A
TAPE UNIT SCSI COMMANDS
BITS
3 2
0 1
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
DESCRIPTION
1 0
0 0
BT
Flag Link
4-75