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Reviewer: Arvid G. Larson

The author states in the introduction that he would have preferred that this book be called The Microsoft vision for distributed components, and rightly so. He goes on to say that “this book is for planners, technical managers, and software developers who are looking for a detailed overview of the Microsoft architecture for large-scale distributed applications. This architecture will impact the entire software industry. This book provides an essential road map to that architecture.” Such broad assertions notwithstanding, this book is really a collection of Microsoft design approaches for distributed commerce–oriented applications. It presents a relatively broad overview of the Microsoft Distributed Component Architecture (MDCA). The MDCA incorporates all of the object-oriented technology created or used by Microsoft to enable distributed commerce applications based on components. At the low level, this includes Java, component models (COM), and distributed component models (DCOM). At the high level, it includes coordinating technologies such as transactions, clusters, and security. Within the MDCA schema, components are coordinated by Microsoft's distributed component management system, the Microsoft Transaction Server. These coordinated components are organized in clusters. Components can send messages back and forth reliably and securely, using Microsoft's message queueing protocols. Each of these concepts is discussed, along with the technical issues involved in each layer of the Microsoft solution, how these layers work together, and how this architectural vision might influence the future of the software industry. This discussion is spread over 12 relatively easy-to-read chapters containing many examples and illustrations. Early chapters provide an overview of the architecture, introduce COM and DCOM concepts and issues, and discuss the use of Java as a COM and DCOM implementation tool, as well as the application of Java and Visual Basic in creating COM wrappers. Higher-level issues such as persistence, sharing and scalability, transactions and databases, and multitier architectures are then discussed in individual chapters. The following chapters consider broad-based concepts, including security, clustering, and message queueing. The concluding chapter attempts to wrap up these disparate technologies in the context of the MDCA, and gives the author's ten rules for developing distributed component systems within the MDCA. An example commerce system is threaded through the text to show how these approaches may be employed to design a brokering system that can be used to match up buyers and sellers and to coordinate the transfer of goods for money. Many well-designed code samples are incorporated into the text and are available at the publisher's Web site. In addition, the author's often strongly worded opinions regarding the obvious viability of the “exciting architectural vision” encompassed by MDCA and associated distributed commerce applications, compared to those advocated by IBM and other Microsoft competitors, are scattered throughout the text. This text presents a fairly current report on the status of MDCA-related concepts and the underlying large-scale distributed system development work being conducted by Microsoft. Not all readers will share the author's enthusiasm for Microsoft-based applications implementations, but intellectual curiosity about the Microsoft distributed object strategy should stimulate most readers who are at all interested in the future of enterprise computing. Most readers can easily skim over the author's promotional chaff and gather his many nuggets of technological insight into the utility of the Microsoft strategy. Thus, I recommend this text to all students of distributed applications computing who want to learn, in relatively simple terms, how Microsoft has used Visual Basic, Java, COM, and DCOM to build a fairly sound basis for electronic commerce.