xviii
PREFACE
Although unusual. we have nevertheless been able to reduce the total number
of pages. This reduction is partly caused by discarding subjects such as distributed
garbage collection and electronic payment protocols, and also reorganizing the
last four chapters.
As in the previous edition, the book is divided into two parts. Principles of
distributed systems are discussed in chapters
2-9,
whereas overall approaches to
how distributed applications should be developed (the paradigms) are discussed in
chapters 10-13. Unlike the previous edition, however, we have decided not to dis-
cuss complete case studies in the paradigm chapters. Instead, each principle is
now explained through a representative case. For example, object invocations are
now discussed as a communication principle in Chap. 10 on object-based distri-
buted systems. This approach allowed us to condense the material, but also to
make it more enjoyable to read and study.
Of course. we continue to draw extensively from practice to explain what dis-
tributed systems are all about. Various aspects of real-life systems such as Web-
Sphere MQ, DNS, GPS, Apache, CORBA, Ice, NFS, Akamai, TIBlRendezvous.
Jini, and many more are discussed throughout the book. These examples illustrate
the thin line between theory and practice, which makes distributed systems such
an exciting field.
A number of people have contributed to this book in various ways. We would
especially like to thank D. Robert Adams, Arno Bakker, Coskun Bayrak, Jacques
Chassin de Kergommeaux, Randy Chow, Michel Chaudron, Puneet Singh
Chawla, Fabio Costa, Cong Du, Dick Epema, Kevin Fenwick, Chandan a Gamage.
Ali Ghodsi, Giorgio Ingargiola, Mark Jelasity, Ahmed Kamel, Gregory Kapfham-
mer, Jeroen Ketema, Onno Kubbe, Patricia Lago, Steve MacDonald, Michael J.
McCarthy, M. Tamer Ozsu, Guillaume Pierre, Avi Shahar, Swaminathan Sivasu-
bramanian, Chintan Shah, Ruud Stegers, Paul Tymann, Craig E. Wills, Reuven
Yagel, and Dakai Zhu for reading parts of the manuscript, helping identifying
mistakes in the previous edition, and offering useful comments.
Finally, we would like to thank our families. Suzanne has been through this
process seventeen times now. That's a lot of times for me but also for her. Not
once has she said: "Enough is enough" although surely the thought has occurred
to her. Thank you. Barbara and Marvin now have a much better idea of what
professors do for a living and know the difference between a good textbook and a
bad one. They are now an inspiration to me to try to produce more good ones
than bad ones (AST).
Because I took a sabbatical leave to update the book, the whole business of
writing was also much more enjoyable for Marielle, She is beginning to get used
to it, but continues to remain supportive while alerting me when it is indeed time
to redirect attention to more important issues. lowe her many thanks. Max and
Elke by now have a much better idea of what writing a book means, but compared
to what they are reading themselves, find it difficult to understand what is so exci-
ting about these strange things called distributed systems. I can't blame them (MvS).
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