ISO/IEC 14776-415:2019

ISO/IEC 14776-415
Edition 1.0 2019-12
INTERNATIONAL
STANDARD
colour
inside
Information technology – Small Computer System Interface (SCSI) –
Part 415: SCSI Architecture Model - 5 (SAM-5)

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ISO/IEC 14776-415
Edition 1.0 2019-12
INTERNATIONAL
STANDARD
colour
inside
Information technology – Small Computer System Interface (SCSI) –

Part 415: SCSI Architecture Model - 5 (SAM-5)

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 35.200 ISBN 978-2-8322-7662-4

ISO/IEC
14776-415
Information technology -
Small Computer System Interface (SCSI) -
Part 415: SCSI Architecture Model - 5 (SAM-5)
Reference number
Printed Wednesday, October 30, 2019 4:56 pm

- 2 - ISO/IEC 14776-415:2019 © ISO/IEC 2019
1 Scope. 15
2 Normative references. 15
3 Terms, definitions, symbols, abbreviations, and conventions. 15
3.1 Terms and definitions . 15
3.2 Symbols and Abbreviations. 30
3.2.1 Abbreviations . 30
3.2.2 Units. 30
3.3 Keywords. 30
3.4 Editorial conventions . 32
3.5 Numeric and character conventions. 33
3.5.1 Numeric conventions . 33
3.5.2 Byte encoded character strings conventions . 34
3.6 UML notation conventions. 34
3.6.1 Notation conventions overview . 34
3.6.2 Constraint and note conventions . 34
3.6.3 Class diagram conventions. 35
3.6.4 Object diagram conventions . 40
3.7 State machine conventions . 42
3.7.1 State machine conventions overview. 42
3.7.2 Transitions . 43
3.7.3 Messages, requests, indications, confirmations, responses, and event notifications. 43
3.7.4 State machine counters, timers, and variables. 44
3.8 Bit and byte ordering . 44
3.9 Notation for procedure calls. 46
4 SCSI architecture model . 47
4.1 Overview. 47
4.2 Compliance requirements. 47
4.3 The SCSI distributed service model . 49
4.4 The SCSI client-server model. 50
4.4.1 SCSI client-server model overview. 50
4.4.2 Synchronizing client and server changes . 51
4.4.3 Server request/response ordering . 51
4.5 The SCSI structural model . 52
4.6 SCSI classes . 53
4.6.1 SCSI classes overview . 53
4.6.2 SCSI Domain class. 54
4.6.3 Service Delivery Subsystem class. 55
4.6.4 SCSI Device class . 55
4.6.4.1 SCSI Device class overview. 55
4.6.4.2 SCSI Device Name attribute . 56
4.6.5 SCSI Port class. 57
4.6.5.1 SCSI Port class overview. 57
4.6.5.2 Relative Port Identifier attribute. 58
4.6.6 SCSI Target Port class . 58
4.6.6.1 SCSI Target Port class overview. 58
4.6.6.2 Target Port Identifier attribute. 58
4.6.6.3 Target Port Name attribute. 59
4.6.6.4 Send Data-In operation . 59
4.6.6.5 Receive Data-Out operation. 59
4.6.6.6 Terminate Data Transfer operation . 59
4.6.6.7 Send Command Complete operation. 59
4.6.6.8 Task Management Function Executed operation. 59
4.6.7 Task Router class . 59
4.6.7.1 Task Router class overview . 59
4.6.7.2 Route Command operation . 60

4.6.7.3 Route Task Management Function operation . 60
4.6.7.4 Reroute Conglomerate Command operation . 61
4.6.7.5 Reroute Conglomerate Task Management Functions operation. 61
4.6.7.6 Stop Conglomerate Task Management Functions Rerouting operation . 62
4.6.8 SCSI Initiator Port class. 62
4.6.8.1 SCSI Initiator Port class overview . 62
4.6.8.2 Initiator Port Identifier attribute . 63
4.6.8.3 Initiator Port Name attribute . 63
4.6.8.4 Send SCSI Command operation. 63
4.6.8.5 Send Task Management Request operation. 63
4.6.8.6 Get Initiator Port Identifier operation . 63
4.6.8.7 Get Initiator Port Name operation. 63
4.6.9 SCSI Target Device class. 64
4.6.10 Logical Unit Conglomerate class . 65
4.6.11 Level 1 Hierarchical Logical Unit class . 66
4.6.12 Level 2 Hierarchical Logical Unit class . 67
4.6.13 Level 3 Hierarchical Logical Unit class . 68
4.6.14 Level 4 Hierarchical Logical Unit class . 68
4.6.15 Hierarchical Logical Unit class. 68
4.6.16 Management Logical Unit class. 68
4.6.17 Well Known Logical Unit class. 69
4.6.18 Logical Unit class. 69
4.6.18.1 Logical Unit class overview . 69
4.6.18.2 LUN attribute . 71
4.6.18.3 Logical Unit Name attribute. 71
4.6.18.4 Dependent Logical Unit attribute. 72
4.6.18.5 Device Type attribute . 72
4.6.19 Device Server class . 72
4.6.19.1 Device Server class overview . 72
4.6.19.2 Data-In Delivered operation . 72
4.6.19.3 Data-Out Received operation. 72
4.6.19.4 Data Transfer Terminated operation . 73
4.6.20 Copy Manager class . 73
4.6.20.1 Copy Manager class overview . 73
4.6.20.2 Create ROD Token operation. 73
4.6.20.3 Process ROD Token operation . 73
4.6.21 Task Manager class. 73
4.6.21.1 Task Manager class overview. 73
4.6.21.2 SCSI Command Received operation . 73
4.6.21.3 Task Management Request Received operation . 74
4.6.21.4 Data Transfer Terminated operation . 74
4.6.21.5 Nexus Loss operation. 74
4.6.21.6 Transport Reset operation. 74
4.6.21.7 Power Loss Expected operation. 74
4.6.22 Task Set class. 74
4.6.23 Command class . 74
4.6.23.1 Command class overview . 74
4.6.23.2 I_T_L Nexus attribute. 74
4.6.23.3 Command Identifier attribute. 75
4.6.23.4 Task Attribute attribute . 75
4.6.23.5 CDB attribute. 75
4.6.23.6 CRN attribute. 75
4.6.23.7 Command Priority attribute. 75
4.6.23.8 Status attribute . 75
4.6.23.9 Sense Data attribute. 75
4.6.23.10 Sense Data Length attribute. 75
4.6.23.11 Service Response attribute . 75
4.6.23.12 Status Qualifier attribute. 75

- 4 - ISO/IEC 14776-415:2019 © ISO/IEC 2019
4.6.23.13 First Burst Enabled attribute. 75
4.6.23.14 Device Server Buffer attribute . 75
4.6.23.15 Application Client Buffer Offset attribute . 76
4.6.23.16 Request Byte Count attribute . 76
4.6.23.17 Delivery Result attribute . 76
4.6.24 Task Management Function class . 76
4.6.24.1 Task Management Function class overview . 76
4.6.24.2 Function Identifier attribute. 76
4.6.24.3 I_T Nexus attribute. 76
4.6.24.4 I_T_L Nexus attribute. 76
4.6.24.5 Command Identifier attribute. 76
4.6.24.6 Service Response attribute . 76
4.6.24.7 Additional Response Information attribute . 77
4.6.25 Administrative Logical Unit class . 77
4.6.25.1 Administrative Logical Unit class overview. 77
4.6.25.2 Rerouted commands and task management functions. 77
4.6.25.2.1 Overview. 77
4.6.25.2.2 Commands rerouted due to incorrect logical unit selection. 77
4.6.25.2.3 Command rerouting in response to an administrative logical unit request . 77
4.6.25.2.4 Task management function rerouting in response to an administrative logical unit request 78
4.6.26 Subsidiary Logical Unit class . 79
4.6.26.1 Subsidiary Logical Unit class overview . 79
4.6.26.2 Binding attribute . 79
4.6.26.3 Host Bind Identifier attribute. 79
4.6.27 SCSI Initiator Device class. 80
4.6.28 Application Client class. 81
4.6.28.1 Application Client class overview . 81
4.6.28.2 Command Complete Received operation . 81
4.6.28.3 Received Task Management Function Executed operation. 81
4.6.28.4 Nexus Loss operation. 82
4.6.28.5 Transport Reset operation. 82
4.6.29 Application Client Task Management Function class . 82
4.6.29.1 Application Client Task Management Function class overview. 82
4.6.29.2 Function Identifier attribute. 82
4.6.29.3 I_T Nexus attribute. 82
4.6.29.4 I_T_L Nexus attribute. 82
4.6.29.5 Command Identifier attribute. 82
4.6.29.6 Service Response attribute . 82
4.6.29.7 Additional Response Information attribute . 82
4.6.30 Application Client Task Set class. 83
4.6.31 Application Client Command class . 83
4.6.31.1 Application Client Command class overview.83
4.6.31.2 I_T_L Nexus attribute. 83
4.6.31.3 Command Identifier attribute. 83
4.6.31.4 CDB attribute. 84
4.6.31.5 Task Attribute attribute . 84
4.6.31.6 Status attribute . 84
4.6.31.7 Service Response attribute . 84
4.6.31.8 Data-In Buffer attribute. 84
4.6.31.9 Data-In Buffer Size attribute. 84
4.6.31.10 Data-Out Buffer attribute . 85
4.6.31.11 Data-Out Buffer Size attribute . 85
4.6.31.12 CRN attribute. 85
4.6.31.13 Command Priority attribute. 85
4.6.31.14 First Burst Enabled attribute. 85
4.6.31.15 Sense Data attribute. 85
4.6.31.16 Sense Data Length attribute. 85
4.6.31.17 Status Qualifier attribute. 85

4.6.32 Discovery class. 85
4.6.32.1 Discovery class overview . 85
4.6.32.2 I_T Nexus attribute. 86
4.6.32.3 I_T_L Nexus attribute. 86
4.6.32.4 Return I_T Nexus operation . 86
4.6.32.5 Return I_T_L Nexus operation . 86
4.7 Logical unit number (LUN). 86
4.7.1 Overview. 86
4.7.2 Logical unit representation format. 87
4.7.3 LUNs overview. 87
4.7.4 Minimum LUN addressing requirements. 87
4.7.5 Single level LUN structure . 88
4.7.6 Complex LUN structures. 91
4.7.6.1 Complex LUN structures overview. 91
4.7.6.2 Logical unit conglomerate LUN structure . 91
4.7.6.3 Hierarchical LUN structure . 92
4.7.7 Addressing methods . 95
4.7.7.1 Simple logical unit addressing method. 95
4.7.7.2 Peripheral device addressing method. 95
4.7.7.3 Flat space addressing method . 97
4.7.7.4 Logical unit addressing method. 98
4.7.7.5 Extended logical unit addressing. 99
4.7.7.5.1 Extended logical unit addressing formats. 99
4.7.7.5.2 Well known logical unit addressing. 102
4.7.7.5.3 Extended flat space addressing method. 103
4.7.7.5.4 Long extended flat space addressing method. 103
4.7.7.5.5 Logical unit not specified addressing. 104
4.8 SCSI ports . 104
4.8.1 SCSI port configurations. 104
4.8.2 SCSI devices with multiple SCSI ports . 105
4.8.3 SCSI target device with multiple SCSI ports structure.106
4.8.4 SCSI initiator device with multiple SCSI initiator ports structure. 107
4.8.5 SCSI device with multiple SCSI ports structure. 107
4.8.6 SCSI initiator device view of SCSI target device with multiple SCSI target ports. 108
4.8.7 SCSI target device view of a SCSI initiator device with multiple SCSI initiator ports. 111
4.9 The SCSI model for distributed communications . 112
5 SCSI command model . 117
5.1 The Execute Command procedure call . 117
5.2 Command descriptor block (CDB). 118
5.3 Status . 120
5.3.1 Status codes . 120
5.3.2 Status qualifier . 121
5.3.3 Status precedence. 124
5.4 SCSI transport protocol services for SCSI commands.124
5.4.1 SCSI transport protocol services for SCSI commands overview. 124
5.4.2 Command and status SCSI transport protocol services . 125
5.4.2.1 Command and status SCSI transport protocol services overview . 125
5.4.2.2 Send SCSI Command SCSI transport protocol service request . 125
5.4.2.3 SCSI Command Received SCSI transport protocol service indication . 125
5.4.2.4 Send Command Complete SCSI transport protocol service response . 126
5.4.2.5 Command Complete Received SCSI transport protocol service confirmation. 126
5.4.3 Data transfer SCSI transport protocol services. 127
5.4.3.1 Overview . 127
5.4.3.2 Data-In delivery service. 129
5.4.3.2.1 Send Data-In SCSI transport protocol service request. 129
5.4.3.2.2 Data-In Delivered SCSI transport protocol service confirmation . 129
5.4.3.3 Data-Out delivery service. 129

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5.4.3.3.1 Receive Data-Out SCSI transport protocol service request . 129
5.4.3.3.2 Data-Out Received SCSI transport protocol service confirmation. 130
5.4.3.4 Terminate Data Transfer service. 130
5.4.3.4.1 Terminate Data Transfer SCSI transport protocol service request. 130
5.4.3.4.2 Data Transfer Terminated SCSI transport protocol service confirmation . 131
5.5 Command lifetime. 131
5.6 Aborting commands. 132
5.7 Command processing example. 139
5.8 Commands that complete with CHECK CONDITION status. 140
5.8.1 Overview. 140
5.8.2 Handling commands when ACA is not in effect.140
5.8.3 Aborting commands terminated with a CHECK CONDITION status without establishing an ACA 140
5.9 Auto contingent allegiance (ACA). 141
5.9.1 ACA overview . 141
5.9.2 Establishing an ACA . 141
5.9.3 Handling new commands received on the faulted I_T nexus when ACA is in effect . 142
5.9.4 Handling new commands received on non-faulted I_T nexuses when ACA is in effect . 142
5.9.4.1 Command processing that is permitted for commands received on a non-faulted
I_T nexuses during ACA . 142
5.9.4.2 Handling new commands received on non-faulted I_T nexuses when ACA is in effect. 142
5.9.5 Clearing an ACA condition. 143
5.10 Overlapped commands . 144
5.11 Incorrect logical unit numbers for commands. 145
5.12 Task attribute exception conditions . 145
5.13 Sense data . 146
5.13.1 Command terminated sense data or polled sense data . 146
5.13.2 Command completed sense data . 146
5.14 Unit attention conditions . 146
5.14.1 Unit attention conditions that are not coalesced . 146
5.14.2 Coalescing unit attention conditions . 149
6 SCSI events and event notification model . 151
6.1 SCSI events overview . 151
6.2 Establishing a unit attention condition subsequent to detection of an event . 153
6.3 Conditions resulting from SCSI events. 154
6.3.1 Power on. 154
6.3.2 Hard reset . 155
6.3.3 Logical unit reset. 155
6.3.4 I_T nexus loss. 156
6.3.5 Power loss expected. 156
6.4 SCSI transport protocol services for event notification. 157
6.4.1 SCSI transport protocol service for event notification overview. 157
6.4.2 Nexus Loss SCSI transport protocol service indication . 157
6.4.3 Transport Reset SCSI transport protocol service indication . 157
6.4.4 Power Loss Expected SCSI transport protocol service indication . 157
7 Task management functions. 159
7.1 Task management function procedure calls. 159
7.2 ABORT TASK. 160
7.3 ABORT TASK SET. 161
7.4 CLEAR ACA . 161
7.5 CLEAR TASK SET . 162
7.6 I_T NEXUS RESET. 162
7.7 LOGICAL UNIT RESET. 163
7.8 QUERY TASK . 163
7.9 QUERY TASK SET . 164
7.10 QUERY ASYNCHRONOUS EVENT.164
7.11 Task management function lifetime. 166

7.12 SCSI transport protocol services for task management functions. 166
7.12.1 SCSI transport protocol services for task management functions overview. 166
7.12.2 Send Task Management Request SCSI transport protocol service request. 167
7.12.3 Task Management Request Received SCSI transport protocol service indication. 167
7.12.4 Task Management Function Executed SCSI transport protocol service response. 167
7.12.5 Received Task Management Function Executed SCSI transport protocol service confirmation. 168
7.13 Task management function example.
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