User's Guide

Chapter 2 Emulated Medium Changer SCSI Commands
Reserve (16h)
96 Quantum DX-Series Software Interface Guide
unit. If, after honoring an Element Reservation, any other initiator
issues a command other than Release to that element, the command is
rejected with a Reservation Conflict status. A Release command issued
by another initiator is ignored by the reserved element.
Table 62 Reserve
Command
Bit/Byte 7 6 5 4 3 2 1 0
0
1
2
3
4
5
• Logical Unit Number
The Logical Unit Number must always be 0. This field indicates the
logical unit to which the command is sent.
• 3rdPty and 3rd Party ID
The 3rd party reservation option for Reserve Unit allows an initiator
to reserve a logical unit for another SCSI device. This option is for
systems that use Copy and is implemented by the DX-Series system.
•If the 3rd party (3rdPty) bit is 0, the option is not requested
• If the 3rdPty bit is 1, Reserve Unit reserves the logical unit for
the SCSI device specified in the 3rd party device ID field
• The DX-Series system preserves the reservation until any 1 of the
4 conditions mentioned occurs
• The DX-Series system ignores any attempt made by any other
initiator to release the reservation and returns a Good status
Operation Code (16h)
Logical Unit Number 3rdPty 3rd Party ID Element
Reservation ID
(MSB)
Element List Length
(LSB)
Unused Reserved (00h) Flag (0) Link (0)
Tech Tip: The DX-Series system does not support 3rd part
reservation or 3rd party ID.