Hitachi HUS154530VLF400 User Manual

Hitachi Ultrastar 15K450 (FC-AL) Hard Disk Drive Specification

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Generation is a counter that increments when PERSISTENT RESERVE OUT command with “Register” or “Preempt and 
Clear” completes successfully. Generation is set to 0 as part of the power on reset process and hard reset process.

The Generation field contains a 32-bit counter that the Target shall increment every time a PERSISTENT RESERVE OUT 
command requests a Register, a Clear, a Preempt, or a Preempt and Abort service action. The counter shall not be incremented 
by a PERSISTENT RESERVE IN command, by a PERSISTENT RESERVE OUT command that performs a Reserve or 
Release service action, or by a PERSISTENT RESERVE OUT command that is not performed due to an error or reservation 
conflict. Regardless of the APTPL value the generation value shall be set to 0 as part of the power on reset process.

The Additional Length field contains a count of the number of bytes in the reservation key list. If the allocation length speci-
fied by the PERSISTENT RESERVE IN command is not sufficient to contain the entire parameter list, then only the bytes 
from 0 to the maximum allowed allocation length shall be sent to the Initiator. The incremental remaining bytes shall be trun-
cated, although the Additional Length field shall still contain the actual number of bytes in the reservation key list without con-
sideration of any truncation resulting from an insufficient allocation length. This shall not be considered an error.

The Reservation Key list contains the 8-byte reservation keys for all Initiators that have registered through all ports with the 
Target.