Modernizing Legacy Systems

Most organizations rely on complex enterprise information systems (EISs) to codify their business practices and collect, process, and analyze business data. These EISs are large, heterogeneous, distributed, constantly evolving, dynamic, long-lived, and mission critical. In other words, they are a complicated system of systems. As features are added to an EIS, new technologies and components are selected and integrated. In many ways, these information systems are to an enterprise what a brain is to the higher species--a complex, poorly understood mass upon which the organism relies for its very existence. To optimize business value, these large, complex systems must be modernized--but where does one begin? This book uses an extensive real-world case study (based on the modernization of a thirty year old retail system) to show how modernizing legacy systems can deliver significant business value to any organization.

Get your code under control in a series of small, specific steps About This Book Learn to extract and replace legacy artifacts, Improve your application from the ground up while keeping your codebase fully operational, Improve the quality of your legacy applications. Who This Book Is For PHP developers from all skill levels will be able to get value from this book and will be able to transform their spaghetti code applications to clean, modular applications. If you are in the midst of a legacy refactor or you find yourself in a state of despair caused by the code you have inherited, this is the book for you. All you need is to have PHP 5.0 installed, and you're all set to change the way you maintain and deploy your code! What You Will Learn Replace global and new with dependency injection Extract SQL statements to gateways Convert action logic to controllers Remove repeated logic in page scripts Create maintainable PHP code from crufty legacy PHP In Detail Have you noticed that your legacy PHP application is composed of page scripts placed directly in the document root of the web server? Or, do your page scripts, along with any other classes and functions, combine the concerns of model, view, and controller into the same scope? Is the majority of the logical flow incorporated as include files and global functions rather than class methods? Working with such a legacy application feels like dragging your feet through mud, doesn't it?This book will show you how to modernize your application in terms of practice and technique, rather than in terms of using tools like frameworks and libraries, by extracting and replacing its legacy artifacts. We will use a step-by-step approach, moving slowly and methodically, to improve your application from the ground up. We'll show you how dependency injection can replace both the new and global dependencies. We'll also show you how to change the presentation logic to view files and the action logic to a controller. Moreover, we'll keep your application running the whole time. Each completed step in the process will keep your codebase fully operational with higher quality. When we are done, you will be able to breeze through your code like the wind. Your code will be autoloaded, dependency-injected, unit-tested, layer-separated, and front-controlled. Most of the very limited code we will add to your application is specific to this book. We will be improving ourselves as programmers, as well as improving the quality of our legacy application. Style and approach This book gives developers an easy-to-follow, practical and powerful process to bring their applications up to a modern baseline. Each step in the book is practical, self-contained and moves you closer to the end goal you seek: maintainable code. As you follow the exercises in the book, the author almost anticipates your questions and you will have the answers, ready to be implemented on your project.

Kill It with Fire chronicles the challenges of dealing with aging computer systems, along with sound modernization strategies. How to survive a legacy apocalypse “Kill it with fire,” the typical first reaction to a legacy system falling into obsolescence, is a knee-jerk approach that often burns through tons of money and time only to result in a less efficient solution. This book offers a far more forgiving modernization framework, laying out smart value-add strategies and proven techniques that work equally well for ancient systems and brand-new ones. Renowned for restoring some of the world’s oldest, messiest computer networks to operational excellence, software engineering expert Marianne Bellotti distills key lessons and insights from her experience into practical, research-backed guidance to help you determine when and how to modernize. With witty, engaging prose, Bellotti explains why new doesn’t always mean better, weaving in illuminating case studies and anecdotes from her work in the field. You’ll learn: Where to focus your maintenance efforts for maximum impact and value How to pick the right modernization solutions for your specific needs and keep your plans on track How to assess whether your migrations will add value before you invest in them What to consider before moving data to the cloud How to determine when a project is finished Packed with resources, exercises, and flexible frameworks for organizations of all ages and sizes, Kill It with Fire will give you a vested interest in your technology’s future.

Every major enterprise has a significant installed base of existing software systems that reflect the tangled IT architectures that result from decades of patches and failed replacements. Most of these systems were designed to support business architectures that have changed dramatically. At best, these systems hinder agility and competitiveness and, at worst, can bring critical business functions to a halt. Architecture-Driven Modernization (ADM) restores the value of entrenched systems by capturing and retooling various aspects of existing application environments, allowing old infrastructures to deliver renewed value and align effectively with enterprise strategies and business architectures. Information Systems Transformation provides a practical guide to organizations seeking ways to understand and leverage existing systems as part of their information management strategies. It includes an introduction to ADM disciplines, tools, and standards as well as a series of scenarios outlining how ADM is applied to various initiatives. Drawing upon lessons learned from real modernization projects, it distills the theory and explains principles, processes, and best practices for every industry. Acts as a one-stop shopping reference and complete guide for implementing various modernization models in myriad industries and departments Every concept is illustrated with real-life examples from various modernization projects, allowing you to immediately apply tested solutions and see results Authored by the Co-chair of the Object Management Group (OMG) Architecture-Driven Modernization (ADM) Task Force, which sets definitive systems modernization standards for the entire IT industry A web site supports the book with up to date coverage of evolving ADM Specifications, Tutorials, and Whitepapers, allowing you to remain up to date on modernization topics as they develop

Software services are established as a programming concept, but their impact on the overall architecture of enterprise IT and business operations is not well-understood. This has led to problems in deploying SOA, and some disillusionment. The SOA Source Book adds to this a collection of reference material for SOA. It is an invaluable resource for enterprise architects working with SOA.The SOA Source Book will help enterprise architects to use SOA effectively. It explains: What SOA is How to evaluate SOA features in business terms How to model SOA How to use The Open Group Architecture Framework (TOGAF™) for SOA SOA governance This book explains how TOGAF can help to make an Enterprise Architecture. Enterprise Architecture is an approach that can help management to understand this growing complexity.

While containers, microservices, and distributed systems dominate discussions in the tech world, the majority of applications in use today still run monolithic architectures that follow traditional development processes. This practical book helps developers examine long-established Java-based models and demonstrates how to bring these monolithic applications successfully into the future. Relying on their years of experience modernizing applications, authors Markus Eisele and Natale Vinto walk you through the steps necessary to update your organization's Java applications. You'll discover how to dismantle your monolithic application and move to an up-to-date software stack that works across cloud and on-premises installations. Learn cloud native application basics to understand what parts of your organization's Java-based applications and platforms need to migrate and modernize Understand how enterprise Java specifications can help you transition projects and teams Build a cloud native platform that supports effective development without falling into buzzword traps Find a starting point for your migration projects by identifying candidates and staging them through modernization steps Discover how to complement a traditional enterprise Java application with components on top of containers and Kubernetes

Get more out of your legacy systems: more performance, functionality, reliability, and manageability Is your code easy to change? Can you get nearly instantaneous feedback when you do change it? Do you understand it? If the answer to any of these questions is no, you have legacy code, and it is draining time and money away from your development efforts. In this book, Michael Feathers offers start-to-finish strategies for working more effectively with large, untested legacy code bases. This book draws on material Michael created for his renowned Object Mentor seminars: techniques Michael has used in mentoring to help hundreds of developers, technical managers, and testers bring their legacy systems under control. The topics covered include Understanding the mechanics of software change: adding features, fixing bugs, improving design, optimizing performance Getting legacy code into a test harness Writing tests that protect you against introducing new problems Techniques that can be used with any language or platform—with examples in Java, C++, C, and C# Accurately identifying where code changes need to be made Coping with legacy systems that aren't object-oriented Handling applications that don't seem to have any structure This book also includes a catalog of twenty-four dependency-breaking techniques that help you work with program elements in isolation and make safer changes.

This book gathers the proceedings of the I-ESA’18 Conference, which was organised by the Fraunhofer IPK, on behalf of the European Virtual Laboratory for Enterprise Interoperability (INTEROP-VLab) and the DFI, and was held in Berlin, Germany in March 2018. It presents contributions ranging from academic research and case studies, to industrial and administrative experiences with interoperability that show how, in a globalised market scenario – where the ability to cooperate with other organisations efficiently is essential in order to remain economically, socially and environmentally cost-effective – the most innovative digitised and networked enterprises ensure that their systems and applications can interoperate across heterogeneous collaborative networks of independent organisations. Furthermore, the content addresses smart services, and the business impact of enterprise interoperability on organisations. Many of the papers in this ninth volume of the I-ESA Conference proceedings include examples and illustrations to help deepen readers’ understanding and generate new ideas. Offering a detailed guide to the state of the art in systems interoperability, the book will be of great value to all engineers and computer scientists working in manufacturing and other process industries, and to software engineers and electronic and manufacturing engineers working in academic settings.