1、INCITS TR-28-2002 INCITS Technical Report Information Technology - SCSI Domain Validation (SDV) Developec IJ the InterNational Committee for Information Technology Standards (INCITS) I NCITS TR-28-2002 INCITS Technical Report Secretariat Information Technology Industry Council Abstract This technica
2、l report describes the methods by which users may measure the performance characteristics of a parallel SCSI domain. This report does not provide definitions or specifications of components utilized in configuring the domain. Physical attributes of the domain are defined in the SCSI family of standa
3、rds. These standards should be consulted before implementing the recommendations outlined in this technical report. The information in this technical report does not supersede any requirements in the referenced standards. INCITS Tech n i ca I This Technical Report is one in a series produced by the
4、InterNational Committee for Information Technology Standards (INCITS). The secretariat for INCITS is held by the Information Technology Industry Council (ITI), 1250 Eye Street, NW, Suite As a by-product of the standards development process and the resources of knowledge devoted to it, INCITS from ti
5、me to time produces Technical Reports. Such Technical Reports are not standards, nor are they intended to be used as such. Repod 200, Washington, DC 20005. Series INCITS Technical Reports are produced in some cases to disseminate the technical and logical concepts reflected in standards already publ
6、ished or under development. In other cases, they derive from studies in areas where it is found premature to develop a standard due to a still changing technology, or inappropriate to develop a rigorous standard due to the existence of a number of viable options, the choice of which depends on the u
7、sers particular requirements. These Technical Reports, thus, provide guidelines, the use of which can result in greater consistency and coherence of information processing systems. When the draft Technical Report is completed, the Technical Committee approval process is the same as for a draft stand
8、ard. Processing by INCITS is also similar to that for a draft standard. PATENT STATEMENT CAUTION: The developers of this technical report have requested that holders of patents that may be required for the implementation of the technical report, disclose such patents to the publisher. However, neith
9、er the developers nor the publisher have undertaken a patent search in order to identify which, if any, patents may apply to this technical report. As of the date of publication of this technical report, following calls for the identification of patents that may be required for the implementation of
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12、cesses. No representation is made or implied that licenses are not required to avoid infringement in the use of this technical report. Published by American National Standards Institute 25 West 43rd Street, New York, New York 10036 Copyright O 2002 by Information Technology Industry Council (ITI) Al
13、l rights reserved No part of this publication may be reproduced in any form, in an electronic retrieval system or otherwise, without prior written permission of the publisher. Printed in the United States of America Table of Contents 1 Scope I 2 References . 1 2.1 Approved referen . 1 2.2 References
14、 under development . 3 Definitions, abbreviations, and keywords . 3.1 Definitions . 3.2 Abbreviations . 3 3.3 Keywords . 4 4 Examples of parallel SCSI domain configurations . 5 4.1 SCSI bus segment and driver-receiver connections . 5 4.2 Typical configurations 6 5 Domain examination . 9 5.1 General
15、9 5.2 Topology discovery . 9 5.3 Assumptions . 9 5.4 Data patterns . 9 5.5 Test descriptions 9 5.5.1 Test order . 9 5.5.2 Test conditions 10 5.5.3 Basic test 10 5.5.4 Enhanced test . 10 5.5.5 Test output 11 5.6 Margin Test . 5.6.1 Assumption 5.6.2 Test order 5.6.3 Test conditions 11 5.6.4 Margin tes
16、t and parameters 12 5.6.5 Test combinations . 13 5.6.6 Test direction 13 5.6.7 Test criteria . 13 5.6.8 Test output 13 5.6.9 Flow chart . 13 Table of Figures Figure I . Driver-receiver connection 5 Figure 2 . Simplified domain A . 6 Figure 3 - Simplified domain B . 6 Figure 4 - Example domain with e
17、xpander 7 Figure 5 - Example dual initiator domain . 7 Figure 7 - Domain examination 14 Figure 7 continued - Domain validation . 15 Figure 7 continued - Domain examination . 16 Figure 6 - Example of complex domain . 8 I INCITS TR-28-2002 1 Scope This technical report provides guidance to users of pa
18、rallel SCSI beyond that contained in the formal standards. This technical report describes the methods of characterizing a parallel SCSI domain by varying analog driver parameters and monitoring the results. The architecture for varying receiver parameters may be consistent with that used when varyi
19、ng analog driver parameters. The architecture for varying receiver parameters is not addressed in this technical report. This technical report addresses measuring the performance of driver-receiver connections. SCSI Parallel Interface-4 specifies minimum requirements of those connections. 2 Referenc
20、es The following standards contain provisions that, through reference in the text, constitute provisions of this technical report. At the time of publication, the revisions indicated were valid. All standards are subject to revision, and parties to agreements based on this technical report are encou
21、raged to investigate the possibility of applying the most recent revisionsleditions of the standards listed below. Copies of the following standards may be obtained from ANSI: approved ANSI standards, approved and draft international and regional standards (SO, IEC, CENICENELEC, ITUT), and approved
22、and draft foreign standards (including BSI, JIS, and DIN). For further information, contact ANSI Customer Service Department at 212-642-4900 (phone), 212-302-1286 (fax) or via the World Wide Web at http:/www.ansi.org. For further information or copies of NCITS Standards contact: NCITS Secretariat at
23、 202-737-8888 (phone), 202-638-4922 (fax) or via E-mail at ncitsitic.org. To obtain copies of these standards contact: NCITS Online Store, managed by Techstreet, at 1327 Jones Drive, Ann Arbor, MI 48105 at 734-302-7801 (phone), 800-699-9277 (phone), or 734-302-781 1 (fax); or Global Engineering at 1
24、5 Inverness Way East, Englewood, CO 801 12-5704 at 303-792-2181 (phone), 800-854-71 79 (phone), or 303-792-21 92 (fax). 2.1 Approved references Currently, there are no approved normative references. 2.2 References under development At the time of publication, the following referenced standards were
25、still under development. For information on the current status of the standard, or regarding availability, contact the relevant standards body or other organization as indicated. T10/1365-D, SCSI Parallel Interface-4 TI011 157-D, SCSI Architecture Model-2 T10/1416-D, SCSI Primary Commands-3 NCITS TR
26、-23:1998, SCSI Enhanced Parallel Interface 1 INCITS TR-28-2002 3 Definitions, abbreviations, and keywords 3.1 Definitions 3.1.1 application client is found in the SCSI Architecture Model-2 standard. 3.1.2 handshake with a REQ/ACK offset of zero. application client: An object that is the source of SC
27、SI commands. Further definition of an asynchronous transfer: An information transfer that uses the asynchronous REQ/ACK 3.1.3 3.1.4 expanders, terminators, and cable plants that logically connect all attached SCSI initiators and SCSI targets. 3.1.5 the REQ or ACK signals. 3.1.6 driver: The circuitry
28、 used to control the state of the SCSI bus segment. 3.1.7 driver-receiver connection: An assembly of driver, receiver, terminators, and the cable plant that produce the electrical coupling between the driver and receiver involved in the measurement. 3.1.8 expander: A device that connects SCSI bus se
29、gments together to form a single domain. 3.1.9 fast-5: Negotiated to receive synchronous data at a transfer period that translates into a transfer rate less than or equal to 5 megatransfers per second. 3.1.10 fast-IO: Negotiated to receive synchronous data at a transfer period that translates into a
30、 transfer rate greater than 5 megatransfers per second and less than or equal to a transfer rate of 10 megatransfers per second. byte: Indicates an 8-bit construct. domain: The configuration of components within a service delivery subsystem that includes SCSI double transition (DT): The latching of
31、data on both the assertion edge and the negation edge of 3.1.1 1 fast-20: Negotiated to receive synchronous data at a transfer period that translates into a transfer rate greater than 10 megatransfers per second and less than or equal to a transfer rate of 20 megatransfers per second. 3.1.12 fast-40
32、: Negotiated to receive synchronous data at a transfer period that translates into a transfer rate greater than 20 megatransfers per second and less than or equal to a transfer rate of 40 megatransfers per second. 3.1.13 fast-80: Negotiated to receive synchronous data at a transfer period that trans
33、lates into a transfer rate greater than 40 megatransfers per second and less than or equal to a transfer rate of 80 megatransfers per second. 3.1.14 fast-160: Negotiated to receive synchronous data at a transfer period that translates into a transfer rate of 160 megatransfers per second. 3.1.15 init
34、iator: Synonymous with SCSI initiator port (see 3.1.26). 3.1.16 logical unit: An externally addressable entity within a SCSI target device. See the SCSI Architecture Model-2 standard for a detailed definition of a logical unit. 3.1.17 logical unit number (LUN): An identifier for a logical unit. 2 IN
35、CITS TR-28-2002 3.1.18 margining: The process of measuring the response of driver-receiver connections to controllable changes in the driver properties. 3.1.19 megatransfers per second: The repetitive rate that data are transferred across the bus. This is equivalent to 2“20 bytes per second on an 8-
36、bit wide bus. 3.1.20 path: The cable, printed circuit board or other means for providing the conductors and insulators that connect two or more points. 3.1.21 receiver: The circuitry used to detect the state of the SCSI bus segment. 3.1.22 SCSI address: The decimal representation of the unique addre
37、ss assigned to a SCSI device. 3.1.23 SCSI bus segment: A SCSI bus segment consists of all the conductors and connectors required to attain signal line continuity between every driver, receiver, and two terminators for each signal. It is not necessary that a SCSI bus segment contain any specific comb
38、ination of devices but a segment has at least two devices attached. Devices include: targets, initiators, and expanders in this context. The end- points of SCSI bus segments are defined by the position of the terminators. 3.1.24 SCSI device: A device containing at least one SCSI port and the means t
39、o connect its drivers and receivers to the bus segment. 3.1.25 SCSI ID: The bit-significant representation of the SCSI address where IDO is the least significant bit. 3.1.26 SCSI initiator port: A SCSI initiator device object acts as the connection between application clients and the service deliver
40、y subsystem through which requests and responses are routed. See the SCSI Architecture Model-2 standard for a detailed definition of a SCSI initiator port. 3.1.27 SCSI target port: A SCSI target device object that contains a task router and acts as the connection between device servers and task mana
41、gers and the service delivery subsystem through which requests and responses are routed. See the SCSI Architecture Model-2 standard for a detailed definition of a SCSI target port. 3.1.28 SCSI Terminator: The terminator is at each end of a SCSI bus segment. The terminator provides impedance match an
42、d biasing, holding the bus in a negated state when it is not driven. 3.1.29 service delivery subsystem: That part of a SCSI I/O system that transmits service requests to a logical unit or target and returns logical unit or target responses to an initiator. 3.1.30 single transition (ST): The latching
43、 of data only on the assertion edge of the REQ or ACK signals. 3.1.31 synchronous transfer: An information transfer that uses an REQ/ACK offset other than zero. 3.1.32 target: Synonymous with SCSI target port (see 3.1.27). 3.2 Abbreviations Async CRC DT ECP LU N SCSI ST T Asynchronous data transfer
44、Cyclic redundancy check Double transition Expander communication protocol (see SCSI Parallel Interface-4) Logical unit number Small computer system interface Single transition Terminator 3 INCITS TR-28-2002 3.3 Keywords 3.3.1 3.3.2 3.3.3 phrase “it is recommended.” may: A keyword that indicates flex
45、ibility of choice with no implied preference. may not: Keywords that indicates flexibility of choice with no implied preference. should: A keyword indicating flexibility of choice with a preferred alternative; equivalent to the 4 INCITS TR-28-2002 4 Examples of parallel SCSI domain configurations 4.
46、1 SCSI bus segment and driver-receiver connections A SCSI bus segment consists of all the conductors and connectors required to attain signal line continuity between every driver, receiver, and two terminators for each signal. Examples of SCSI bus segments are shown in Figure 2, Figure 3, Figure 4,
47、Figure 5, and Figure 6. The end-points of SCSI bus segments are defined by the position of the terminators. The driver-receiver connection is an assembly of driver, receiver, terminators, and the cable plant that produce the electrical coupling between the driver and receiver involved in the measure
48、ment. Figure 1 details a complementary set of driver-receiver connections. This technical report considers single driver-receiver connections only. A complete characterization of a SCSI bus segment requires every driver-receiver connection in the SCSI bus segment to be examined. Since SCSI is a bi-d
49、irectional architecture, a minimum of two driver-receiver connections exist in every SCSI bus segment. Complete characterization of a domain requires characterization of all SCSI bus segments in the domain. 27 signals (2 wires per signal on a differential bus) -one signal shown Dr = Driver Circuit Rc = Receiver Circuit Device A to Device B driver-receiver connection Device B to Device A driver-receiver connection -+ .lgl 19.9.I.99=,.=9 II-I-III-III Figure 1 - Driver-receiver connection 5 INCITS TR-28-2002 initiator 6 . 4.2 Typical configurations Domains are configurations,
