Operating instructions

17-2
SCSI REFERENCE 1012975
CHAPTER 17—RELEASE (17h OR 57h)
17.1 ABOUT THIS COMMAND
The autoloader supports both the six-byte and the ten-byte format of the
RELEASE UNIT CDB. The autoloader determines which version of the
command is being used based on the operation code in the CDB. You can use
either version of the command, depending on which version of the RESERVE
command was used, as follows:
 An element reservation must be released using the six-byte RELEASE CDB.
 A 3rd-party reservation must be released using the ten-byte RELEASE CDB.
 A unit reservation may be released using either version of the RELEASE
CDB.
The RELEASE command enables you to release reservations of the autoloader
or elements of the autoloader that you made with the RESERVE (16h or 56h)
command. For information on the RESERVE command, see Chapter 20. For
default element addresses for the autoloader, refer to the figure on Figure 2-1
on page 2-3.
Only the initiator that reserved the autoloader or autoloader elements can
release the reserved autoloader or elements. If another initiator attempts to
release a reserved autoloader or element, the autoloader returns Good status
and does not release the autoloader or element.
Releasing a reservation of the autoloader as a unit also releases all element
reservations for that initiator.
Releasing an unreserved autoloader or unreserved elements of the autoloader
is not an error.
17.2 WHAT YOU SEND TO THE AUTOLOADER
17.2.1 SIX-BYTE CDB (PAGE CODE 17h)
Use the six-byte CDB if you want to release reservations for the autoloader as a
unit or specific elements within the autoloader.
Logical Unit Number – Byte 01, Bits 7 through 5
The value for this field must always be 0.
Element – Byte 01, Bit 0
The valid values for this field are as follows:
0 – Release the autoloader or any reserved elements from reserved status
1 – Release the reserved elements associated with the Reservation Identification
(byte 02) from reserved status