ISO/IEC 14776-326:2015

Information technology — Small computer system interface (SCSI) — Part 326: Reduced block commands (RBC)

ISO/IEC 14776-326:2015(E) defines a Reduced Block Command set for logical block devices. The Reduced Block Commands along with the required SPC-2 commands and their restrictions described in this standard, fully specify the complete command set for RBC logical block devices. It provides a command set of reduced requirements and options from SCSI Block Commands (SBC) (ISO/IEC 14776-321) for block devices. The reduced command set is intended to more closely match the functionality required for simple block logical units. The specified commands place no restrictions on device performance. The initial focus of this command set was to enable rigid disks and removable media devices attached to Serial Bus and utilizing SBP-2 (ISO/IEC 14776-232) for command and control. This second edition cancels and replaces the first edition published in 2002 and constitutes a minor revision. This second edition provides additional explanations and corrects mistakes with respect to the first edition.

Technologies de l'information — Interface de petit système d'ordinateur (SCSI) — Partie 326: Commandes en bloc réduit (RBC)

General Information

• Status: Published
• Publication Date: 08-Sep-2015
• ICS: 35.200 - Interface and interconnection equipment
• Technical Committee: ISO/IEC JTC 1/SC 25 - Interconnection of information technology equipment
• Drafting Committee: ISO/IEC JTC 1/SC 25 - Interconnection of information technology equipment
• Current Stage: 6060 - International Standard published
• Due Date: 20-Oct-2016
• Completion Date: 09-Sep-2015

Relations

• Revises: ISO/IEC 14776-326:2002 - Information technology — Small Computer System Interface (SCSI) — Part 326: Reduced Block Commands (RBC)
• Effective Date: 01-Nov-2014

Standards Content (Sample)

ISO/IEC 14776-326
Edition 2.0 2015-09
INTERNATIONAL
STANDARD

Information technology – Small computer system interface (SCSI) –
Part 326: Reduced block commands (RBC)

ISO/IEC 14776-326:2015-09(en)

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ISO/IEC 14776-326


Edition 2.0 2015-09




INTERNATIONAL



STANDARD



















Information technology – Small computer system interface (SCSI) –

Part 326: Reduced block commands (RBC)



























INTERNATIONAL

ELECTROTECHNICAL

COMMISSION






ICS 35.200 ISBN 978-2-8322-2861-6



  Warning! Make sure that you obtained this publication from an authorized distributor.

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– 2 – ISO/IEC 14776-326:2015 © ISO/IEC 2015
CONTENTS
FOREWORD . 5
1 Scope . 6
2 Normative references . 6
3 Terms, definitions, abbreviations, keywords, and conventions . 7
3.1 Terms and definitions . 7
3.2 Abbreviations . 8
3.3 Keywords . 8
3.4 Conventions . 9
3.4.1 Non-numeric values . 9
3.4.2 Numeric values . 10
4 RBC device model . 10
4.1 General . 10
4.2 Removable medium device . 10
4.3 Command usage . 11
4.3.1 General . 11
4.3.2 Using the INQUIRY command . 11
4.3.3 Using the REQUEST SENSE command . 11
4.3.4 FORMAT UNIT command progress determination . 11
4.4 Using the PREVENT ALLOW MEDIUM REMOVAL command . 12
4.4.1 General . 12
4.4.2 START STOP UNIT command state restrictions . 12
4.5 Logical Blocks . 12
4.6 Reservations . 13
5 Reduced Block Commands . 14
5.1 General . 14
5.2 FORMAT UNIT command . 16
5.3 READ(10) Command . 17
5.4 READ CAPACITY command . 17
5.5 START STOP UNIT command . 18
5.5.1 General . 18
5.5.2 Power conditions . 19
5.5.3 Enable/Disable bits . 20
5.6 SYNCHRONIZE CACHE command . 21
5.7 VERIFY command . 21
5.8 WRITE(10) command . 22
5.9 Mode parameters . 23
5.9.1 General . 23
5.9.2 Mode parameter list . 23
5.9.3 Mode Parameter header . 23
5.9.4 RBC Device Parameter's page . 23
6 SPC-2 implementation requirements for RBC devices . 25
6.1 General . 25
6.2 INQUIRY command . 25
6.2.1 Standard INQUIRY data . 25
6.2.2 INQUIRY vital product data pages . 26
6.3 MODE SELECT(6) command . 27

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ISO/IEC 14776-326:2015 © ISO/IEC 2015 – 3 –
6.4 MODE SENSE(6) command . 27
6.5 PREVENT ALLOW MEDIUM REMOVAL . 28
6.6 REQUEST SENSE command . 28
6.7 TEST UNIT READY command . 28
6.8 WRITE BUFFER Command . 29
6.8.1 General . 29
6.8.2 Download microcode and save mode (101b) . 30
6.8.3 Download microcode with offsets and save mode (111b) . 30
7 Asynchronous event notification for RBC devices . 30
7.1 General . 30
7.2 Unit attention . 31
7.2.1 General . 31
7.2.2 Power condition change notification . 31
7.3 Deferred errors . 31
7.4 Information exception condition notification . 31
7.5 Event status notification . 31
7.5.1 General . 31
7.5.2 Event Status sense information . 32
7.5.3 Power Management CLASS event INFORMATION field . 32
7.5.4 MEDIA CLASS EVENT INFORMATION field . 33
7.5.5 DEVICE BUSY CLASS EVENT INFORMATION field . 34
7.5.6 Event status retention . 35
7.5.7 Removable medium device initial response . 35
Annex A (normative) RBC device implementation requirements for SBP-2 . 36
A.1 SBP-2 terms and definitions . 36
A.1.1 Terms and definitions . 36
A.1.2 Abbreviations . 38
A.2 SBP-2 storage model . 38
A.2.1 General . 38
A.2.2 Model configuration . 38
A.2.3 Reconnect/Power reset support . 40
A.3 Configuration ROM support . 40
A.3.1 General . 40
A.3.2 Unit Directory – Command_Set_Spec_ID . 40
A.3.3 Unit Directory – Command_Set . 41
A.3.4 Unit Directory – Logical_Unit_Number . 41
A.4 Security support . 41
A.5 Status block support . 41
A.6 Unsolicited Status support . 42
A.6.1 General . 42
A.6.2 Unit attention condition . 42
A.6.3 Event Status retention . 42

Figure A.1 – Mass storage interface block diagram . 39
Figure A.2 – Status block for RBC. 42

Table 1 – RBC direct access commands that are allowed in the presence of various
reservations . 14

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– 4 – ISO/IEC 14776-326:2015 © ISO/IEC 2015
Table 2 – Reduced Block Command set . 15
Table 3 – FORMAT UNIT command . 16
Table 4 – READ (10) Command Descriptor Block. 17
Table 5 – READ CAPACITY Command Descriptor Block . 18
Table 6 – READ CAPACITY data . 18
Table 7 – START STOP UNIT Command Descriptor Block . 19
Table 8 – POWER CONDITIONS . 19
Table 9 – START STOP control bit definitions . 21
Table 10 – SYNCHRONIZE CACHE Command Descriptor Block . 21
Table 11 – VERIFY Command Descriptor Block . 22
Table 12 – WRITE(10) Command Descriptor Block . 22
Table 13 – Mode parameter list . 23
Table 14 – RBC Device Parameters page format . 24
Table 15 – Required SPC-2 commands. 25
Table 16 – Standard Inquiry data format . 26
Table 17 – MODE SELECT(6) Command Descriptor Block . 27
Table 18 – MODE SENSE(6) Command Descriptor Block . 28
Table 19 – FAILURE PREDICTION ASCQ XY definitions . 29
Table 20 – WRITE BUFFER Command Descriptor Block . 29
Table 21 – Asynchronous Event conditions . 30
Table 22 – Power condition sense code and qualifier values . 31
Table 23 – Event status ASCQ values. 32
Table 24 – Event Status INFORMATION field format . 32
Table 25 – POWER MANAGEMENT CLASS EVENT INFORMATION field format . 32
Table 26 – POWER MANAGEMENT CLASS EVENT EVENT field . 33
Table 27 – POWER MANAGEMENT CLASS EVENT STATUS field . 33
Table 28 – MEDIA CLASS EVENT INFORMATION field format . 33
Table 29 – MEDIA CLASS EVENT EVENT field . 34
Table 30 – DEVICE BUSY CLASS EVENT information field format . 34
Table 31 – DEVICE BUSY CLASS EVENT EVENT field . 34
Table 32 – DEVICE BUSY CLASS STATUS field . 35

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ISO/IEC 14776-326:2015 © ISO/IEC 2015 – 5 –
INFORMATION TECHNOLOGY –
SMALL COMPUTER SYSTEM INTERFACE (SCSI) –

Part 326: Reduced block commands (RBC)

FOREWORD
1) ISO (the International Organization for Standardization) and IEC (the International Electrotechnical Commission)
form the specialized system for worldwide standardization. National bodies that are members of ISO or IEC
participate in the development of International Standards through technical committees established by the
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9) Attention is drawn to the possibility that some of the elements of this ISO/IEC publication may be the subject of
patent rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights.
International Standard ISO/IEC 14776-326 was prepared by subcommittee 25: Interconnection
of information technology equipment, of ISO/IEC joint technical committee 1: Information
technology.
This second edition cancels and replaces the first edition published in 2002 and constitutes a
minor revision.
This second edition provides additional explanations and corrects mistakes with respect to the
first edition.
A list of all parts in the ISO/IEC 14776 series, published under the general title Information
technology – Small computer system interface (SCSI), can be found on the IEC website.
This International Standard has been approved by vote of the member bodies, and the voting
results may be obtained from the address given on the second title page.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

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INFORMATION TECHNOLOGY –
SMALL COMPUTER SYSTEM INTERFACE –

Part 326: Reduced block commands (RBC)



1 Scope
This part of ISO/IEC 14776 defines a Reduced Block Command set for logical block devices.
The Reduced Block Commands along with the required SPC-2 commands and their
restrictions described in this standard, fully specify the complete command set for RBC logical
block devices.
The purpose of this part of ISO/IEC 14776 is to provide a command set of reduced
requirements and options from SCSI Block Commands (SBC) (ISO/IEC 14776-321) for block
devices. The reduced command set is intended to more closely match the functionality
required for simple block logical units. The specified commands place no restrictions on
device performance. The initial focus of this command set was to enable rigid disks and
removable media devices attached to Serial Bus and utilizing SBP-2 (ISO/IEC 14776-232) for
command and control.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
ISO/IEC 13213:1994, Information technology – Micoprocessor systems – Control and Status
Registers (CSR) Architecture for microcomputer buses
ISO/IEC 14776-232:2001, Information technology – Small computer system interface (SCSI)
– Part 232: Serial Bus Protocol 2 (SBP-2)
ISO/IEC 14776-321:2001, Information technology – Small Computer System Interface
(SCSI-3) – Part 321: Block commands (SBC)
ISO/IEC 14776-362:2006, Information technology – Small computer system interface (SCSI)
– Part 362: Multimedia commands-2 (MMC-2)
ISO/IEC14776-412, Information technology – Small computer system interface (SCSI) – Part
412: SCSI, Architecture model-2 (SAM-2)
ISO/IEC 14776-452:2005, Information technology – Small computer system interface (SCSI)
– Part 452: Primary commands-2 (SPC-2)
IEEE Standard 1394-1995, High Performance Serial Bus
IEEE Standard 1394A-2000, High Performance Serial Bus Amendment 1

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ISO/IEC 14776-326:2015 © ISO/IEC 2015 – 7 –
3 Terms, definitions, abbreviations, keywords, and conventions
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1.1
additional sense code
ASC
field in the sense data
Note 1 to entry: See 7.20.2 in ISO/IEC 14776-452:2005.
[SOURCE: ISO/IEC 14776-452:2005, 3.1.2, modified – Reference to SPC-2 added.]
3.1.2
additional sense code qualifier
ASCQ
field in the sense data
Note 1 to entry: See 7.20.2 in ISO/IEC 14776-452:2005.
3.1.3
byte
B
eight bit of data
[SOURCE: ISO/IEC 14776-452:2005, 3.1.9, modified – Definition simplified.]
3.1.4
command descriptor block
CDB
structure of up to 16 B in length used to communicate a command from an initiator to a device
[SOURCE: ISO/IEC 14776-452:2005, 3.1.11, modified – Definition changed.]
3.1.5
EVENT field
byte 0 of the sense data INFORMATION field
Note 1 to entry: See Table 24 for the Event Status INFORMATION field format when the sense code indicates
EVENT STATUS NOTIFICATION (38h).
3.1.6
logical unit
part of the device that is an instance of a device model
Note 1 to entry: For example mass storage, CD-ROM or a printer are device models.
Note 2 to entry: In devices that implement one or more logical units, the device type of the logical units may
differ.
[SOURCE: ISO/IEC 14776-452:2005, 3.1.30, modified – Definition and explanatory
information changed.]
3.1.7
sense data
data describing an error or exceptional device condition that a device delivers to an initiator

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[SOURCE: ISO/IEC 14776-452:2005, 3.1.47, modified – Definition simplified and explanatory
information deleted.]
3.1.8
sense key
field in the sense data
Note 1 to entry: See 7.20.3 in ISO/IEC 14776-452.
[SOURCE: ISO/IEC 14776-452:2005, 3.1.48, modified – Definition changed.]
3.1.9
status
response information sent from a device to an initiator upon completion of each command
[SOURCE: ISO/IEC 14776-452:2005, 3.1.52, modified – Definition simplified and explanatory
information deleted.]
3.1.10
unit attention condition
condition that a logical unit maintains while it has asynchronous status information to report to
one or more initiators
[SOURCE: ISO/IEC 14776-452:2005, 3.1.58, modified – "State" has been replaced by
"condition" and refence information has been deleted.]
3.1.11
vendor specific
bit, field, code value, etc., not defined in this standard, that may be vendor defined
[SOURCE: ISO/IEC 14776-452:2005, 3.1.59, modified – Minor editorial change of the
definition.]
3.2 Abbreviations
The following abbreviations are used in this standard:
ASC Additional Sense Code
ASCQ Additional Sense Code Qualifier
CDB Command Descriptor Block
MMC-2 Multi-Medial Commands 2
RBC Reduced Block Commands (this standard)
SAM-2 SCSI Architecture Model 2
SBC SCSI Block Commands
SBP-2 Serial Bus Protocol 2
SPC-2 SCSI Primary Commands 2
3.3 Keywords
Several keywords are used to differentiate levels of requirements and options, as follows.
3.3.1
expected
keyword used to describe the behavior of the hardware or software in the design models
assumed by this standard. Other hardware and software design models may also be
implemented.

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ISO/IEC 14776-326:2015 © ISO/IEC 2015 – 9 –
3.3.2
ignored
keyword that describes bits, bytes, quadlets, or fields whose values are not checked by the
recipient
3.3.3
mandatory
keyword that indicates items required to be implemented as defined by this standard
3.3.4
may
keyword that indicates flexibility of choice with no implied preference
3.3.5
optional
keyword that describes features which are not required to be implemented by this standard.
However, if any optional feature defined by the standard is implemented, it shall be
implemented as defined by the standard.
3.3.6
reserved
keyword used to describe objects (eg., bits, bytes, and field) or the code values assigned to
these objects in cases where either the object or the code value is set aside for future
standardization. Usage and interpretation may be specified by future extensions to this or
other standards. A reserved object shall be zeroed or, upon development of a future standard,
set to a value specified by such a standard. The recipient of a reserved object shall not check
its value. The recipient of a defined object shall check its value and reject reserved code
values.
3.3.7
shall
keyword that indicates a mandatory requirement. Designers are required to implement all
such mandatory requirements to assure interoperability with other products conforming to this
standard.
3.4 Conventions
The following conventions shall be understood by the reader in order to comprehend this
standard.
3.4.1 Non-numeric values
Lowercase is used for words having the normal English meaning. Certain words and terms
used in this standard have a specific meaning beyond the normal English meaning. These
words and terms are defined either in Clause 3 or in the text where they first appear.
The names of abbreviations, commands, and acronyms are in all uppercase (e.g., TEST UNIT
READY command).
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