Excelling as a network server, a database machine, and a general-purpose processor, the AS/400 is rapidly becoming one of the most popular midrange computers on the market. Much more than a general overview of this powerful new model, this book arms programmers and operators with all the knowledge and skills needed to exploit this powerful new model to its fullest. It is useful for systems professionals and programmers who have little or no experience with the AS/400.

The purpose of this book is to present control language on the AS/400, which handles communication between the user and the machine. The book is divided into ten chapters that present the main concepts of the language gradually. The text is accompanied by adequate illustrations and many examples to convey the information more efficiently and help the reader learn. All the chapters end with exercises, which are useful to verify one’s understanding of the concepts presented.

The book begins with a look at the history and technical background of the IBM midrange family. This first chapter, “The Story of the AS/400,” covers the history of the System 3X family, the predecessors of the AS/400; the basic concepts of the AS/400; and some basic system commands that can be used to get technical information about this machine.

The main goal of the second chapter, “An Introductory Tutorial,” is to give readers hands-on experience using the AS/400. Terms and concepts of the control language are defined, familiarizing readers with objects, libraries, jobs, queues, and subsystems. Also described are the first actions one must know to use an AS/400, from the sign-on procedure to using the Programming Development Manager and other job control commands. The chapter is illustrated with corresponding screens and workflow diagrams.

AS/400 control language conventions regarding the manipulation of variables, operators, and expressions are clearly presented in chapter 3, “The Basic Elements.” The definitions are supplemented by examples.

Because the function of a control language is to perform certain actions on a specified object in order to achieve a purpose (such as creating a user profile, submitting a batch job, or copying a database file), chapter 4 (“Control Flow”) is dedicated to clarifying the purpose of control flow constructs in the control language and to explain how such a construct can be realized.

Chapter 5, “Library and Object,” presents upper-level control language facilities. A good understanding of these concepts is important because the object is the basic unit on which actions can be performed by the system, and the library organizes objects. This chapter explains how to create libraries and objects and manage them safely.

The AS/400 has a unique concept of work and its management. Therefore, the author describes these concepts in chapter 6, “Jobs,” before any control language commands are explained.

Chapter 7, “Interprogram Communication,” describes special objects and concepts, such as data area, data queue, and switches, which are used in communication between a control language program and another control language or high-level language program.

Chapter 8, “Message Handling,” introduces this mechanism on the AS/400 and the corresponding set of message-handling commands. Ways of communicating from user to user, from user to program, and from program to program are treated.

Chapter 9, “File Processing,” introduces file processing commands on the AS/400.

The last part of this book, “Advanced Topics,” is not for beginners but for those who have some experience. The control language for the AS/400 provides more than 700 commands, but the system also offers the user the ability to create her or his own commands for specific purposes.

This user-friendly work is a step-by-step guide to all practical aspects of the AS/400 control language for programmers and users. The command summaries at the end of every chapter are useful. A comprehensive index provides quick access to every topic covered. The layout is agreeable. The author is not only an expert with over ten years’ programming experience, but a good teacher.