1、ANSI INCITS 314-1998 (R2003)(formerly ANSI NCITS 314-1998)for Information Technology SCSI-3 Medium Changer Commands (SMC)Copyright American National Standards Institute Provided by IHS under license with ANSINot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Copyright
2、 American National Standards Institute Provided by IHS under license with ANSINot for ResaleNo reproduction or networking permitted without license from IHS-,-,-ANSINCITS 314-1998American National Standardfor Information Technology SCSI-3 Medium Changer Commands (SMC)SecretariatInformation Technolog
3、y Industry CouncilApproved May 19, 1998American National Standards Institute, Inc.AbstractThis standard defines the SCSI commands and model for independent medium changer devices and at-tached medium changer functions integrated into other SCSI devices.Copyright American National Standards Institute
4、 Provided by IHS under license with ANSINot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Approval of an American National Standard requires review by ANSI that therequirements for due process, consensus, and other criteria for approval havebeen met by the standards
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10、al Standards Institute.American National StandardPublished byAmerican National Standards Institute, Inc.11 West 42nd Street, New York, NY 10036Copyright 1998 by Information Technology Industry Council (ITI)All rights reserved.No part of this publication may be reproduced in anyform, in an electronic
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14、d.Copyright American National Standards Institute Provided by IHS under license with ANSINot for ResaleNo reproduction or networking permitted without license from IHS-,-,-iContentsPageForeword .ivIntroduction vii1 Scope 12 Normative references . 33 Definitions, symbols and abbreviations. 43.1 Defin
15、itions . 43.2 Symbols and abbreviations . 73.3 Keywords 73.4 Conventions 84 Overview. 95 Medium changer models 115.1 Independent medium changer 115.2 Attached medium changer 115.3 Medium changer elements 115.4 Medium transport element 125.5 Storage element 135.6 Import/export element . 135.7 Data tr
16、ansfer element 135.8 Element status maintenance requirements. 145.9 Volume tag information . 145.10 Primary and alternate volume tag information 155.11 Volume tag information format 156 Commands for medium changer logical units. 166.1 EXCHANGE MEDIUM command 186.2 INITIALIZE ELEMENT STATUS command 2
17、06.3 MOVE MEDIUM command . 216.4 POSITION TO ELEMENT command 236.5 READ ELEMENT STATUS command 246.5.1 Element status data . 256.5.2 Element status page 266.5.3 Medium transport element descriptor. 276.5.4 Storage element descriptor 296.5.5 Import/export element descriptor . 306.5.6 Data transfer el
18、ement descriptor 326.5.7 Identification descriptor 346.6 RELEASE ELEMENT (6) command . 356.6.1 Logical unit release (Mandatory) . 356.6.2 Element release (Optional) 356.7 RELEASE ELEMENT (10) command . 366.7.1 Third-party release (Mandatory). 366.8 REQUEST VOLUME ELEMENT ADDRESS command . 376.9 RESE
19、RVE ELEMENT (6) command. 406.9.1 Logical unit reservation (Mandatory) 406.9.2 Element reservation (optional) . 416.10 RESERVE ELEMENT (10) command. 42Copyright American National Standards Institute Provided by IHS under license with ANSINot for ResaleNo reproduction or networking permitted without l
20、icense from IHS-,-,-iiPage6.10.1 Third-party reservation (Mandatory). 436.10.2 Superseding reservations 436.11 SEND VOLUME TAG command. 457 Parameters . 497.1 Diagnostic parameters 497.2 Log parameters. 497.3 Mode parameters 507.3.1 Device capabilities page 517.3.2 Element address assignment page 53
21、7.3.3 Transport geometry parameters page 54Tables1 Volume tag information format . 152 Commands for independent medium changers . 163 Commands for attached medium changers . 174 EXCHANGE MEDIUM command. 185 INITIALIZE ELEMENT STATUS command 206 MOVE MEDIUM command 217 POSITION TO ELEMENT command 238
22、 READ ELEMENT STATUS command 249 Element type code 2510 Element status data 2511 Element status page 2612 Medium transport element descriptor. 2713 Storage element descriptor 2914 Import/export element descriptor 3015 Data transfer element descriptor 3216 Identification descriptor fields . 3417 RELE
23、ASE ELEMENT (6) command. 3518 RELEASE ELEMENT (10) command. 3619 RELEASE ELEMENT (10) parameter list. 3720 REQUEST VOLUME ELEMENT ADDRESS command. 3821 Volume element address header . 3922 RESERVE ELEMENT (6) command 4023 Data format of element list descriptors. 4224 RESERVE ELEMENT (10) command 432
24、5 RESERVE ELEMENT (10) ID equivalent to the phrase “it is strongly recommended“.3.4 ConventionsCertain words and terms used in this standard have a specific meaning beyond the normalEnglish meaning. These words and terms are defined either in 3.1 or in the text where they firstappear. Names of comma
25、nds, statuses, sense keys, additional sense codes, and additionalsense code qualifiers are in all uppercase (e.g., REQUEST SENSE). Field names and bit namesare in SMALL CAPS. Lower case is used for words having the normal English meaning.Fields containing only one bit are usually referred to as the
26、name bit instead of the name field.Numbers that are not immediately followed by lowercase b or h are decimal values.Numbers immediately followed by lowercase b (xxb) are binary values.Numbers or upper case letters immediately followed by lowercase h (xxh) are hexadecimalvalues.Lists sequenced by let
27、ters (e.g., a-red, b-blue, c-green) show no priority relationship between thelisted items. Numbered lists (e.g., 1-red, 2-blue, 3-green) show a priority ordering between thelisted items. If a conflict arises between text, tables, or figures, the order of precedence to resolvethe conflicts is text; t
28、hen tables; and finally figures. Not all tables or figures are fully described inthe text. Tables show data format and values. NOTES do not constitute any requirements forimplementors.Copyright American National Standards Institute Provided by IHS under license with ANSINot for ResaleNo reproduction
29、 or networking permitted without license from IHS-,-,-ANSI NCITS 314-199894 OverviewThe SCSI-3 medium changer device class specifies a logical unit that is involved, primarily, withthe movement of removable volumes in a controlled environment without human intervention. TheSCSI-3 device classes that
30、 provide for removable volumes are block, multi-media and sequential.(See the SBC, MMC and SSC standards.)A medium changer logical unit receives commands to move volumes between various elementtypes in the element address space of the medium changer. The element types are storage, datatransfer, medi
31、um transport, and import/export. A volume handling robotic subsystem, addressedas a medium transport element, moves volumes within a medium changer.A medium changer logical unit maintains an inventory of volumes and the element addresswhere they can be found. The medium changer logical unit reports
32、this inventory when requestedas well as identifying the element addresses assigned to different types of elements.Different levels of sophistication may be implemented in how this inventory is managed, reported,detected and maintained. The elements in a medium changer may be reserved to differentini
33、tiators. For example, one data transport element may be reserved for exclusive use by oneinitiator. The primary device, located at that data transfer element, may then be attached tovarious systems for their use. In some cases, the primary device associated with a data transferelement may not be an
34、SCSI device.The split between load and unload control of the medium and read and write control by a primarydevice is a key feature of this device class. The mechanism for coordinating this kind ofsophisticated activity is not specified in this standard. The medium changer device class providesthe me
35、ans for mount/dismount management only.Copyright American National Standards Institute Provided by IHS under license with ANSINot for ResaleNo reproduction or networking permitted without license from IHS-,-,-ANSI NCITS 314-199810Figure 2 shows an example of an independent medium changer. The data t
36、ransfer elements(primary devices) shown may be any type of removable media device such as a tape drive, diskdrive or optical drive. Supporting multiple types of removable media within the same mediumchanger is also permitted. Also, the ports on each primary device may or may not attach to thesame se
37、rvice delivery subsystem and the interfaces to the primary devices may or may not beSCSI. The number and arrangement of elements is arbitrary.Figure 2 - Example independent medium changer deviceThe independent changer model applies to implementations where the medium changer isaddressed as a separat
38、e logical unit. The logical unit for the medium changer may be accessedvia the same SCSI ID as the primary device, or via a different SCSI ID. This type of mediumchanger may support more than one primary device.The attached medium changer model permits a subset of the functions of an independentchan
39、ger to be incorporated directly into a primary device. Only one data transport element ispermitted. In this case, only one logical unit is used to access all functions.A medium changer moves volumes among the several element types accessible to it oncommand from an initiator. Medium changers shall b
40、e capable of reporting the full or emptystatus of any element address in its domain.Copyright American National Standards Institute Provided by IHS under license with ANSINot for ResaleNo reproduction or networking permitted without license from IHS-,-,-ANSI NCITS 314-1998115 Medium changer models5.
41、1 Independent medium changerAn independent medium changer is a device server that returns 8h in the PERIPHERAL DEVICE TYPEfield (see SPC) of INQUIRY command response data.Independent medium changers for the SMC standard respond to a LUN different from those usedby a primary device. Communication wit
42、h a primary device may use the same service deliverysubsystem as the medium changer device, or a different SCSI service delivery subsystem.Primary devices that are not SCSI devices are also permitted. Multiple primary devices may beattached to an independent changer.If a primary device served by the
43、 medium changer is an SCSI device, the primary device may beaddressed on an SCSI-3 service delivery subsystem though the same port as the mediumchanger but with a different LUN or the primary device may be addressed through independentports and any LUN on the same or a different service delivery sub
44、system.The READ ELEMENT STATUS command response data page for each data transfer elementmay provide the identity of the primary device serviced by a medium changer device. Thissupport is optional since a primary device is not required to be an SCSI-3 device.5.2 Attached medium changerAn attached med
45、ium changer is part of a device server that sets the MCHNGR bit to one in itsstandard INQUIRY data (see SPC). Attached medium changers respond to the same LUN as aprimary device that is not a medium changer. In an attached medium changer, the PERIPHERALDEVICE TYPE field of INQUIRY command response d
46、ata returns the type of the primary device.Two medium changer commands, READ ELEMENT STATUS ATTACHED and MOVE MEDIUMATTACHED are added to the command set of the primary device. The other commandsavailable depend on the model for the primary device.5.3 Medium changer elementsA medium changer has an a
47、ddress space separate and distinct from the physical address spaceof an SCSI-3 service delivery subsystem. The term element is used throughout this standard torefer to one member of the medium changer address space. Within a medium changer, theelement addresses are a set of physical locations and me
48、chanisms within the scope of a mediumchanger device.Each element is an instance of one of four element types: Medium Transport Element Storage Element Import/Export Element Data Transfer ElementEach element is a discrete physical entity with a unique element address that may providestorage for zero
49、or one volume. A volume is in exactly one element at a time. The point in timeduring movement when a volume is considered in a different element is implementationdependent. When requested to report element status, a volume shall be reported as being atexactly one element address. The element address shall not be arbitrarily changed by theCopyright American National Standards Institute Provided by IHS under license with
