User's Guide

Chapter 3 Emulated DLT7000 SCSI Commands
Release Unit (17h)
Quantum DX-Series Software Interface Guide 243
Release Unit (17h) 3
The RELEASE UNIT command releases the drive if it is currently
reserved by the requesting initiator. It is not an error to release the tape
drive if it is not currently reserved by the requesting initiator. If the tape
drive is reserved by another initiator, however, it is not released; the tape
drive is only released from the initiator that issued the RELEASE
command.
Table 195 RELEASE
UNIT Command
Descriptor Block -
Data Format
Bit/Byte 7 6 5 4 3 2 1 0
0
1
2-4
5
Table 196 RELEASE
UNIT Command Data
- Field Descriptions
Operation Code (17h)
Logical Unit Number 3rd Pty Third Party Device ID Rsv’d
Reserved
Unused Reserved
Flag (0) Link (0)
Field Name Description
3rdPty 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 this bit is 0, then the third-
party release option is not requested. If this bit is set
to 1, the 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 specified in the Third Party Device ID
field.
Third Party
Device ID
Required if the 3rdPty bit is 1. This field specifies
the SCSI ID of the initiator whose third party
reservation is being released. This field must be set
if the initiator of the original third party RESERVE
is the source of the RELEASE.