SCSI Description
5-98 Maxtor Atlas 10K III
Table 5-120 provides detailed descriptions of each of the PERSISTENT
RESERVATION OUT command’s seven possible service actions (Service Action
codes appear in bits 0 – 4 of Byte 1).
PERSISTENT RESERVATION OUT Command’s Service Action Descr iptions
Type The value of the Type fiel d specifies the chara cteristi cs of the persistent reservation
being e stabli shed for all d ata blocks wi thin t he exten t or w ithi n the lo gical unit. Refer
to Table 5- 121 for the applicabl e Type codes and thei r me anings
Parameter
List Length
Fields contained in the PERSISTENT RESERVATION OUT parameter list specify the res-
ervat ion keys and extent information re quired t o perform a pers istent r eservation ser-
vice action .
The param eter list is 24 bytes in leng th; the Parameter List Length field contai ns 24
(18 h ) b y te s .
00h Register
When th e command execut es a Register service action, it regi sters a res erva-
tion key with a device server without generating a reservation. The device serv-
er holds these reservation keys from each initiator that performs a PERSISTENT
RESER VATION OUT command wit h a Regist er service action until the key is
changed by a new PERSISTENT RESERVATI ON OUT comman d wi th Register
service ac tion fro m the s a me initiator, or u n til the initiator re g istration is re -
moved by:
•Pow e ring down th e l o gi cal un i t, if the l ast
Activate Persist Through Power Loss
(APTPL; see Figure 5-55 and Table 5-61)
received by the device server was 0;
•Perfo rmi ng a Cle ar s e rvi ce actio n ;
•Performing a Pre-empt service action;
•Performing a Pre-empt and Clear service
action; or
•Performing a Register service action from the
same initiator with the value of the service
acti o n re s e rv a ti o n k e y s et to 0.
When a re serv ation key has not yet been estab lished or when the reser vat ion
key h as been rem oved, a reservation key of 0 is used when the initiator per-
forms a PERSISTENT RESERVATION OUT with the Register ser vice action.
When the reservation has been removed, no information is reported for the ini-
tia tor in the Read Keys serv ice action of the result ing PERSI STENT RESERVA-
TION IN command.
01h Reserve
A PERSISTENT RESERVATION OUT command with Reserve service action cre-
ates a persis tent rese rvati on with a specified Scope and Type.
Persistent reservations are not superseded by a new persistent reservation from
any initiato r except by the execution of a PERSISTENT RESERVATION OU T
command that specifies either a Pre-empt or Pre-empt and Clear service action.
New persistent r eservations that do not con flict with an exi sting per sistent res-
ervation execute normally. Persistent reservations of logical units or extents
having the same Type val ue are permitt ed if no confli cting per siste nt reserva -
tions are held by another initi ator. When th ese types of overlapping reserva-
tions are released, each of the extent reservations and logical unit reservations
are r emoved wit h a separate Rel ease service action. Mul tiple i dentical reserva-
tions from the same initiator are all released simultaneously via a single Release
service action that matches the reservations.