Request Sense (03H); Figure 4-68. Request Sense (03H) Command Descriptor Block - Data Format; Table 4-57. Release Unit (17H) Command Descriptor Block - Field Descriptions; Request Sense 03H - Quantum DLT 1 Interface Manual

Chapter 4: SCSI Commands
Table 4-57. RELEASE UNIT (17h) Command Descriptor Block — Field Descriptions
Field Name
LUN
3rdPty
Medium Changer
Considerations

4.18 REQUEST SENSE (03h)

The REQUEST SENSE command tells the target to transfer sense data to the initiator.
Bit
Byte
0
1
2 - 3
4
5
Figure 4-68. REQUEST SENSE (03h) Command Descriptor Block — Data Format
The Sense Data is valid for a CHECK CONDITION or RESERVATION CONFLICT status returned
on the previous command. The target preserves the Sense Data bytes until they are retrieved by the
REQUEST SENSE command or until receipt of any other command from the same initiator.
If the tape drive receives an unsolicited REQUEST SENSE, it returns Sense Data with the appropriate
values in the EOM, Sense Key, Additional Sense Code, and Additional Sense Code Qualifier. The
positional information provided reflects the logical position of the tape drive. The tape drive returns
4-96
Description
Logical Unit Number. The target ignores this field. Only an IDENTIFY message
can change the LUN.
The third-party release option for RELEASE UNIT allows an initiator to release a
logical unit that was previously reserved using the third-party reservation option.
If the third-party (3rdPty) bit is 0, the third-party release option is not requested. If
the 3rdPty bit is 1, the tape drive is released if it was originally reserved by the
same initiator using the third-party reservation option and if the tape drive is the
same SCSI device that was specified in the Third-party Device ID field.
The optional Element Reservation feature defined for Medium Changer devices in
SCSI-2 is not supported. The RELEASE command is defined the same as for the
tape drive. The entire loader can be released. RESERVE/RELEASE of the Loader
and Drive LUNs are handled independently.
7 6
Logical Unit Number
Unused
5 4
Operation Code (03h)
Reserved
Allocation Length
Reserved
July 2004
3 2
Reserved
Flag
81-81276-01 Rev A01
1 0
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