User's Guide

Quantum Scalar Intelligent Libraries SCSI Reference Guide Guide 55
Persistent Reserve Out – 5Fh
What the Library Does With This Command
The library will perform service actions relative to persistent reservations as requested. This includes
creating and clearing reservations.
An I_T nexus performing Persistent Reserve Out service actions is identified by a reservation key.
This command is supported by:
• the Media Changer via the DA blade, or
• the tape drive hosting the media changer control path, in which case this command is handled
completely by the tape drive on behalf of the Media Changer.
Command Usage
This command is used in conjunction with PERSISTENT RESERVE IN to manage persistent reservations.
It can be used to request exclusive access to the device. The PERSISTENT RESERVE IN and
PERSISTENT RESERVE OUT commands should not be used with the RESERVE ELEMENT and
RELEASE ELEMENT commands.
Persistent Reserve Out CDB Format
The PERSISTENT RESERVE OUT CDB format is shown in the following table.
Service Action – This field specifies what reservation action to take as follows:
• 00h Register – Register a reservation key without making a reservation.
• 01h Reserve – Create a persistent reservation of the specified scope and type.
• 02h Release – Releases the selected reservation for the requesting initiator.
• 03h Clear – Clears all reservations keys and all persistent reservations.
• 04h Preempt – Preempt reservations from another initiator.
Table 51 PERSISTENT RESERVE OUT CDB format
Bit
Byte
76543210
0 Op Code (5Fh)
1 Logical Unit Number Service Action
2Scope Type
3
:
6
Reserved
7
Parameter List Length (18h)
8
9 Control