Distributed Systems: Concepts and Design Edition 3 By George Coulouris, Jean Dollimore and Tim Kindberg Addison-Wesley, ©Pearson Education 2001

PREFACE

This third edition of our textbook arrives at a time when distributed systems, particularly the Web and other Internet-based applications and services, are of unprecedented interest and importance. The book aims to convey insight into, and knowledge of, the principles and practice underlying the design of distributed systems, both Internet-based and otherwise. Information is provided in sufficient depth to allow readers to evaluate existing systems or design new ones. Detailed case studies illustrate the concepts for each major topic.

Distributed systems techniques developed over the last two to three decades, such as interprocess communication and remote invocation, distributed naming, cryptographic security, distributed file systems, data replication and distributed transaction mechanisms, provide the run-time infrastructure supporting today's networked computer applications.

Distributed system development relies increasingly on middleware support through the use of software frameworks that provide abstractions such as distributed shared objects, and services including secure communication, authentication and access control, mobile code, transactions and persistent storage mechanisms.

In the near future, distributed applications will enable closer cooperation between users through replicated data and multimedia data streams, and will support user and device mobility using wireless and spontaneous networking.

Developers of distributed systems and applications now benefit from a range of useful languages, tools and environments. These enable students as well as professional developers to construct working distributed applications.

Purposes and readership

The book is intended for use in undergraduate and introductory postgraduate courses. It can equally be used for self-study. We take a top-down approach, addressing the issues to be resolved in the design of distributed systems and describing successful approaches in the form of abstract models, algorithms and detailed case studies of widely-used systems. We cover the field in sufficient depth and breadth to enable readers to go on to study most research papers in the literature on distributed systems.

We aim to make the subject accessible to students who have a basic knowledge of object oriented programming, operating systems and elementary computer architecture. The book includes coverage of those aspects of computer networks relevant to distributed systems, including the underlying technologies for the Internet, wide area, local area and wireless networks. Algorithms and interfaces are presented throughout the book in Java or, in a few cases, ANSI C. For brevity and clarity of presentation, a form of pseudo-code derived from Java/C is also used.

Organization of the book

The following diagram shows the book's chapters under five main topic areas. It is intended to provide a guide to the book's structure and to indicate recommended navigation routes for instructors wishing to provide, or readers wishing to achieve, understanding of the various subfields of distributed system design:

References

The existence of the World Wide Web has changed the way in which a book such as this can be linked to source material including research papers, technical specifications and standards. Many of the source documents are now available on the web; some are available only there. For reasons of brevity and readability, we employ a special form of reference to web material which loosely resembles a URL: references such as [ www.omg.org ] and [ www.rsasecurity.com I ] refer to documentation that is available only on the web. They can be looked up in the reference list at the end of the book, but the full URLs are given only in an online version of the reference list at the book's web site: www.cdk3.net/refs where they take the form of clickable links. Both versions of the reference list include a more detailed explanation of this scheme.

Changes for this edition

This third edition appears some six years after the second edition. The work done to produce this edition is summarized in the table above. The introductory chapters and some others have been largely rewritten and several new chapters have been introduced to reflect new perspectives and technical directions. There has been much reorganization in other chapters, affecting the topics covered, the depth of coverage and the location of material. We have condensed older material to make space for new topics. Some material has been moved to a more prominent position to reflect its new significance. The case studies removed from the second edition can be found on the book's web site, as described below.

Acknowledgements

We are grateful to the many classes of students at Queen Mary and Westfield College whose contributions in seminars and lectures have helped us to produce this new edition, as have the helpful suggestions of many teachers elsewhere. Kohei Honda tested early drafts in classes at QMW and this resulted in some particularly valuable comments.

The following gave their time unstintingly to review substantial portions of the final draft, resulting in substantial improvements: Angel Alvarez, Dave Bakken, John Barton, Simon Boggis, Brent Callaghan, Keith Clarke, Kurt Jensen and Roger Prowse.

We should also like to thank the following, who either gave permission to use their material or suggested topics for inclusion in the book: Tom Berson, Antoon Bosselaers, Ralph Herrtwitch, Frederick Hirsch, Bob Hopgood, Ajay Kshemkalyan, Roger Needham, Mikael Pettersson, Rick Schantz and David Wheeler.

We are grateful to the Department of Computer Science, Queen Mary and Westfield College, for hosting the companion web site and to Keith Clarke and Tom King for their support in setting it up.

Finally, we thank Keith Mansfield, Bridget Allen, Julie Knight and Kristin Erickson of Pearson Education/Addison-Wesley for essential support throughout the arduous process of getting the book into print.