User's Manual

DLT2000 SCSI Interface
8-100 DLT2000/DLT2700 Cartridge Tape Subsystem
8.4.17 RELEASE UNIT (17h)
Bit
76543210
0 Operation Code (17h)
Logical Unit Number 3rdPty Third Party Device ID Rsvd
Reserved
Byte
Unused Flag
1
Link
Reserved
2
Reserved
3
Reserved
4
5
Figure 8-68 RELEASE UNIT CDB
RELEASE UNIT releases the drive if it is currently reserved by the requesting initiator.
It is not an error to attempt to release the drive if it is not currently reserved by the
requesting initiator. However, if it reserved by another initiator, the drive is not
released.
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 the
third-party (3rdPty) bit is zero, then the third-party release option is not requested. If
the 3rdPty bit is one, the drive is released if it was originally reserved by the same
initiator using the third-party reservation option, and if the device is the same SCSI
device that was specified in the third-party device ID field.
8.4.17.1 Medium Changer Considerations
The optional Element reservation feature defined for Medium Changer devices in SCSI-
2 is not supported, so the RELEASE command is defined the same as for the tape drive:
Only the whole loader unit can be released. Reserve/release of the Loader and Drive
LUNs are handled independently.