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Reviewer: Teodor Rus

The declared goal of this book is to provide a systematic treatment of the messaging and queueing systems used as programming techniques to implement various communication paradigms. The authors use IBM jargon to describe their subjects, and IBM products to illustrate their philosophy. The material is divided into four parts: concepts, analysis, design, and development. Part 1, “The Concepts” (chapters 1 to 4), discusses the concepts of message and queue. Chapter 1, “The Beginning of Messaging,” traces the history of messages and queues to the beginning of programming in batch operating systems, and then follows their evolution in the context of computer networks. Chapter 2, “The Purpose of Messaging,” contrasts the asynchronous (time-independent) nature of messaging with the synchronous (time-dependent) nature of other communication techniques that abound in the computer industry. The chapter considers person-to-person as well as program-to-program communication media. Chapter 3, “Messaging Concepts,” examines the important concepts of messaging by means of an example; that same example is then used in the discussion in chapter 4, “Queueing Concepts.” This part of the book is well illustrated and uses good graphics. Part 2, “The Analysis” (chapters 5 and 6), defines the term “messaging” as meaning both messaging and queueing, and discusses system analysis. The two chapters provide hints on analyzing how and why messaging is useful in application development and execution. Chapter 5, “Information Flow Patterns,” examines information flow among communicating programs and develops an informal algebra of information flow patterns. Chapter 6, “Messaging and Queueing Models,” introduces middleware, the communication between hardware and software that facilitates communication by messaging. The types of applications that use middleware are discussed. Some of the graphics in this section are repetitive. Part 3, “The Design” (chapters 7 to 10), approaches the problem of designing applications that use messaging as a communication mechanism. With messaging, all information flow patterns are possible, and it is possible to intermix new and existing applications. Chapter 7, “Application and Communication Environments,” discusses these two environments (the application environments consist of applications and application enablers), as well as fundamental networking concepts and communication models. The chapter uses a pictorial language and trivial examples rather than venturing into abstract formalizations. Chapter 8, “Communication Models,” uses the pictorial language to explore three selected communication models and their middleware: the messaging and queueing style, using the MQI system; the conversation style, using CPI-C or APPC systems; and the remote procedure call style, using RPC. Chapter 9, “Distributed Communication Services,” examines five special services required by distributed application environments: directory management; security systems; data definition and conversion; resource recovery; and system management. Chapter 10, “Approaching Application Design,” shows how applications based on messaging and queueing can be designed using two well-known techniques: function-oriented design and object-oriented design. Part 4, “The Development” (chapters 11 and 12), describes how to develop messaging applications. Messaging and queueing are considered as given software that defines the middleware of a machine, and the challenge is to recognize the uses to which this software can be put. Chapter 11, “MQSeries Messaging and Queuing,” examines the IBM product series of Message Queue Managers and shows the services these products provide. Chapter 12, “The Message Queue Interface,” discusses the interface by which application programs access message-queueing functions in MQSeries products known as the Message Queue Interface (MQI) . This interface is illustrated by programs that implement a file transfer facility. The book concludes with four appendices: Appendix A presents representative examples; Appendix B is a summary of the IBM Message Queueing Interface; Appendix C describes IBM messaging and queueing products available as of the publication of this book; and Appendix D presents a contrasting discussion of the mail system and online messaging. Readers who will benefit the most from this book are those with no previous experience with messaging and queueing, and those who have some experience but no formal training.