User's Guide
Table Of Contents
- Preface
- Theory of Operation
- Media Changer Commands
- Overview of Command and Status Processing
- Media Changer Command Descriptions
- Initialize Element Status Command (07h)
- Inquiry Command (12h)
- Load Unload Command (1Bh)
- Log Sense Command (4Dh)
- Mode Select (6) / (10) Command (15h / 55h)
- Mode Sense (6) / (10) Command (1Ah/ 5Ah)
- Move Medium Command (A5h)
- Persistent Reserve In Command (5Eh)
- Persistent Reserve Out Command (5Fh)
- Position to Element Command (2Bh)
- Prevent/Allow Medium Removal (1Eh)
- Read Buffer Command (3Ch)
- Read Element Status Command (B8h)
- Release Element (10) Command (57h)
- Release Unit (6) Command (17h)
- Report Device Identifier Command (A3h)
- Report LUNS Command (A0h)
- Request Sense Command (03h)
- Reserve Element (10) Command (56h)
- Reserve Element (6) Command (16h)
- Send Diagnostic Command (1Dh)
- Set Device Identifier Command (A4h)
- Test Unit Ready Command (00h)
- Write Buffer Command (3Bh)
- Index
Chapter 2 Media Changer Commands
Persistent Reserve Out Command (5Fh)
Quantum SuperLoader 3 Software Interface Guide 86
05h Pre-empt
and
Clear
A PERSISTENT RESERVE OUT command with a Pre-empt and 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 and 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 and 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 and Clear service action. The reservation key for an initiator
that has sent a
Pre-empt and 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 and Clear service action.
New persistent reservations not in conflict with an existing persistent
reservation execute normally.
Code Name Description