ISO/IEC 13961:2000

Information technology - Scalable Coherent Interface (SCI)

The scalable coherent interface (SCI) provides computer-bus-like services but, instead of a bus, uses a collection of fast point-to-point unidirectional links to provide the far higher throughput needed for high-performance multiprocessor systems. SCI supports distributed, shared memory with optional cache coherence for tightly coupled systems, and message-passing for loosely coupled systems. Initial SCI links are defined at 1 Gbyte/s (16-bit parallel) and 1 Gb/s (serial). For applications requiring modular packaging, an interchangeable module is specified along with connector and power. The packets and protocols that implement transactions are defined and their formal specification is provided in the form of computer programs. In addition to the usual read-and-write transactions, SCI supports efficient multiprocessor lock transactions. The distributed cache-coherence protocols are efficient and can recover from an arbitrary number of transmission failures. SCI protocols ensure forward progress despite multiprocessor conflicts (no deadlocks or starvation).

General Information

• Status: Published
• Publication Date: 30-Jul-2000
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 35.160 - Microprocessor systems
• Technical Committee: ISO/IEC JTC 1/SC 25 - Interconnection of information technology equipment
• Current Stage: PPUB - Publication issued
• Start Date: 30-Nov-1998
• Completion Date: 31-Jul-2000

Standards Content (Sample)

INTERNATIONAL ISO/IEC
STANDARD
13961
IEEE
Std 1596
First edition
2000-07
Information technology –
Scalable Coherent Interface (SCI)
Reference number
ISO/IEC 13961:2000(E)
IEEE Std 1596, 1998 Edition

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Abstract: The scalable coherent interface (SCI) provides computer-bus-like services but,
instead of a bus, uses a collection of fast point-to-point unidirectional links to provide the far
higher throughput needed for high-performance multiprocessor systems. SCI supports
distributed, shared memory with optional cache coherence for tightly coupled systems, and
message-passing for loosely coupled systems. Initial SCI links are defined at 1 Gbyte/s (16-bit
parallel) and 1 Gb/s (serial). For applications requiring modular packaging, an interchangeable
module is specified along with connector and power. The packets and protocols that implement
transactions are defined and their formal specification is provided in the form of computer
programs. In addition to the usual read-and-write transactions, SCI supports efficient
multiprocessor lock transactions. The distributed cache-coherence protocols are efficient and
can recover from an arbitrary number of transmission failures. SCI protocols ensure forward
progress despite multiprocessor conflicts (no deadlocks or starvation).
Keywords: bus architecture, bus standard, cache coherence, distributed memory, fiber optic,
interconnect, I/O system, link, mesh, multiprocessor, network, packet protocol, ring, seamless
distributed computer, shared memory, switch, transaction set.

––––––––––
The Institute of Electrical and Electronics Engineers, Inc.
345 East 47th Street, New York, NY 10017-2394, USA
Copyright © 1998 by the Institute of Electrical and Electronics Engineers, Inc.
All rights reserved. First published in 1998.
ISBN 2-8318-5375-3
No part of this publication may be reproduced in any form, in an electronic retrieval system or otherwise, without
the prior written permission of the publisher.

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INTERNATIONAL ISO/IEC
STANDARD
13961
IEEE
Std 1596
First edition
2000-07
Information technology –
Scalable Coherent Interface (SCI)
Sponsor
Microprocessor and Microcomputer Standards Subcommittee
of the IEEE Computer Society
PRICE CODE
XC
For price, see current catalogue

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– 2 – ISO/IEC 13961:2000(E)
IEEE Std 1596, 1998 Edition
CONTENTS
Page
FOREWORD .12
Clause
1 Introduction. 19
1.1 Document structure. 19
1.2 SCI overview . 20
1.2.1 Scope and directions. 20
1.2.2 The SCI approach . 21
1.2.3 System configurations. 22
1.2.4 Initial physical models . 23
1.2.5 SCI node model . 24
1.2.6 Architectural parameters . 25
1.2.7 A common CSR architecture . 25
1.2.8 Structure of the specification. 26
1.3 Interconnect topologies. 26
1.3.1 Bridged systems . 26
1.3.2 Scalable systems . 27
1.3.3 Interconnected systems . 27
1.3.4 Backplane rings . 27
1.3.5 Interconnected rings . 28
1.3.6 Rectangular grid interconnects. 29
1.3.7 Butterfly switches. 30
1.3.8 Vendor-dependent switches . 31
1.4 Transactions .
...