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Chapter 3 Media Changer Commands
Persistent Reserve Out Command (5Fh)
Quantum ATL SuperLoader Software Interface Guide
109
05h
Pre-empt
& Clear
A PERSISTENT RESERVE OUT command with a Pre-empt & Clear
service action removes all persistent reservations for all initiators that
have been registered with the Service action Reservation key specified in
the PERSISTENT RESERVE OUT command’s parameter list. It also
establishes a persistent reservation for the pre-empting initiator. Any
commands from the initiators being pre-empted are terminated as if an
ABORT TASK management function had been performed by the pre-
empted initiator. If a PERSISTENT RESERVE OUT command is sent that
specifies a Pre-empt & Clear service action and no persistent reservation
exists for the initiator identified by the Service action Reservation key, it is
not an error condition. If the key is registered, however, the Clear portion
of the action executes normally.
A UNIT ATTENTION condition is established for the pre-empted
initiators. The sense key is set to UNIT ATTENTION; the additional sense
data is set to RESERVATIONS PREEMPTED. Commands that follow, and
retries of commands that timed out because there were cleared are subject
to the persistent reservation restrictions set by the pre-empting initiator.
The persistent reservation thus created by the pre-empting initiator is
defined by the Scope and Type fields of the PERSISTENT RESERVE OUT
command and the corresponding fields of the command’s parameter list.
The Pre-empt & Clear service action clears any ACA or CA condition
associated with the initiator that is pre-empted and clears any tasks with
an ACA attribute from that initiator.
The reservation key for the other initiators pre-empted are removed by
the Pre-empt & Clear service action. The reservation key for an initiator
that has sent a Pre-empt & Clear action with its own reservation key
specified in the service action’s reservation key remains unchanged,
although all other specified clearing actions, releasing actions, and
reservation actions are performed.
Persistent reservations are not superseded by a new persistent reservation
from any initiator except via execution of a PERSISTENT RESERVE OUT
that specifies either the Pre-empt or Pre-empt & Clear service action. New
persistent reservations not in conflict with an existing persistent
reservation execute normally.
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Description
Summary of Contents for SuperLoader DLT
Page 1: ...ATL SuperLoader DLT and ATL SuperLoader LTO Software Interface Guide 81 60220 01 A02...
Page 18: ...Preface Document Conventions xviii Quantum ATL SuperLoader Software Interface Guide...
Page 44: ...Chapter 2 Messages Supported SCSI Messages 26 Quantum ATL SuperLoader Software Interface Guide...
Page 196: ...Index 178 Quantum ATL SuperLoader Software Interface Guide...