Fujitsu MBC2073RC Manual Do Utilizador

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4.1   Control/Sense Commands  
 
C141-C013 
201 
4.1.18  PERSISTENT RESERVE OUT (5F)  
 
 
Bit 
Byte 
X'5F' 
Service Action 
Scope 
Type 
Parameter List Length (MSB) 
Parameter List Length (LSB) 
 
This command is used for reserving so that the particular initiator can use the 
logical unit exclusively or share with others.  The command shall be used in 
conjunction with the PERSISTENT RESERVE IN command and shall have no 
relevance to the RESERVE and RELEASE commands. 
By using the reservation key defined by the INIT, PERSISTENT RESERVATION 
can be used to identify initiators that execute any of the Service Actions of the 
PERSITENT RESERVE OUT commands and that conflict with a reserve 
condition established by the RESERVE command.  An INIT can check to see 
which INITs hold conflicting or illegal reserve conditions by using the 
PERSISTENT RESERVE IN command and, if necessary, an INIT can make new 
reserve conditions preempt these reserve conditions by using the PERSISTENT 
RESERVE OUT command. 
Since set reserve conditions cannot be reset by processing such as TARGET 
RESET task, PERSISTENT RESERVATION can be used to have multiple INITs 
share a device.  The PERSISTENT RESERVE OUT and PERSISTENT 
RESERVE IN commands provide a fundamental mechanism to analyze reserve 
conditions that change dynamically in a multi-initiator system using multi-port 
TARGs.  It becomes possible to identify whether TARGs have particular reserve 
conditions, and to remove reserve conditions from INITs that have errors or are 
uncooperative. 
If the reserve condition implemented with the RESERVE/RESERVE 
EXTENDED command is held when a drive receives this command, this 
command is rejected with the report of the RESERVATION CONFLICT status.