There are hundreds of thousands of AS/400s around the world that are running legacy applications - applications that were developed early in the life of the AS/400 or for the System/36 or System/38 or even the System/3! Many of these applications are the backbone of your business. They manage your payables and receivables, run your payroll, balance your accounts, and provide the tools that you use to make important business decisions. Should they be updated to more current technology to take advantage of the powerful enhancements IBM has made to the AS/400, OS/400, and RPG? Many would say "No" without thinking through the implications of that decision. Putting your company"s IT resources in a condition of stasis while technology moves on may be a costly business mistake. It is not only possible, but also profitable, to derive some of the benefits of new technology from within a legacy application. IBM"s recent enhancements provide a means of immediately increasing application reliability and programmer productivity with relatively little effort, while building a firm basis for the future of your business. While the technology means new concepts to be learned and new programming skills to be acquired, very few of these new enhancements are so radically different that they fall outside the grasp of the average RPG programmer. This book is a tutorial aimed at showing programmers how to convert and re-engineer their applications by taking them through a re-engineering of a sample application - step by step. Author Paul Tuohy covers conversion of RPG IV programs as well as re-engineering them to take full advantage of RPG IV and ILE. He also covers triggers, referential integrity, and APIs so that your applications can take advantage of all the new technology that is available today. This book will be a valuable aid as you evaluate your legacy applications and then move into re-engineering. Upon completion of this book, you will be able to: Understand the re-engineering process, assess the business reasons for re-engineering, evaluate legacy applications" need for re-engineering, enhance and modularize your applications and programs with RPG IV and ILE, know the difference between conversion and re-egineering with RPG IV, understand the basics and more advanced features of RPG IV, convert to RPG IV using IBM"s or third party software, incorporate built-in functions to enhance your applications, understand and implement powerful subprocedures in your programs, enhance your applications design with prototyping, use ILE effectively in the re-engineering process, implement service programs to strengthen your applications, incorporate triggers and referential integrity for standardization and security of your database, and utilize the new, powerful APIs to broaden the scope of your application.