Modernizing Legacy Systems: Software Technologies, Engineering Processes, and Business Practices
"The potential impact of this book cannot be overstressed. Software systems that are not continually and adequately evolved and, in particular, legacy systems that have not been so maintained, can threaten an organization's very survival. I recommend the book as a must for people directly involved in such evolution, whether as customers, managers and resource providers, or as implementers."--M. M. Lehman, Emeritus Professor, Middlesex UniversityBusinesses inevitably face a critical choice in the design and maintenance of their software systems: Dismantle older systems and completely replace them, or incrementally modernize existing systems. Many businesses choose the latter course, seeking to maximize their existing investment and preserve valuable business knowledge, while adapting to rapidly evolving technologies.Modernizing Legacy Systemsis a much-needed guide, showing how to implement a successful modernization strategy and describing specifically a risk-managed, incremental approach--one that encompasses changes in software technologies, engineering processes, and business practices.Key topics include:Making a case for modernizationUnderstanding requirements and constraintsMaintaining performance, data integrity, and securityDesigning and deploying the target architectureMigrating code and dataEstimating costsPlanning the modernization effortFor every topic, this book presents current standards and available products that support legacy system modernization. In addition, a large retail-supply-system case study--a system written in COBOL being modernized to one based on the J2EE architecture--runs throughout this book to demonstrate a real-world legacy system modernization effort.0321118847B01232003