The IT industry is obsessed with new technologies. Courses, books, and magazines mostly focus on what is new. Starting with what a legacy system looks like to applying various techniques for maintaining and securing these systems, this book gives you all the knowledge you need to maintain a legacy system.

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.

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.

Summary The Mikado Method is a book written by the creators of this process. It describes a pragmatic, straightforward, and empirical method to plan and perform non-trivial technical improvements on an existing software system. The method has simple rules, but the applicability is vast. As you read, you'll practice a step-by-step system for identifying the scope and nature of your technical debt, mapping the key dependencies, and determining the safest way to approach the "Mikado"—your goal. About the Technology The game "pick-up sticks" is a good metaphor for the Mikado Method. You eliminate "technical debt" —the legacy problems embedded in nearly every software system— by following a set of easy-to-implement rules. You carefully extract each intertwined dependency until you expose the central issue, without collapsing the project. About the Book The Mikado Method presents a pragmatic process to plan and perform nontrivial technical improvements on an existing software system. The book helps you practice a step-by-step system for identifying the scope and nature of your technical debt, mapping the key dependencies, and determining a safe way to approach the "Mikado"—your goal. A natural by-product of this process is the Mikado Graph, a roadmap that reflects deep understanding of how your system works. This book builds on agile processes such as refactoring, TDD, and rapid feedback. It requires no special hardware or software and can be practiced by both small and large teams. Purchase of the print book includes a free eBook in PDF, Kindle, and ePub formats from Manning Publications. What's Inside Understand your technical debt Surface the dependencies in legacy systems Isolate and resolve core concerns while creating minimal disruption Create a roadmap for your changes About the Authors Ola Ellnestam and Daniel Brolund are developers, coaches, and team leaders. They developed the Mikado Method in response to years of experience resolving technical debt in complex legacy systems. Table of Contents PART 1 THE BASICS OF THE MIKADO METHOD Meet the Mikado Method Hello, Mikado Method! Goals, graphs, and guidelines Organizing your work PART 2 PRINCIPLES AND PATTERNS FOR IMPROVING SOFTWARE Breaking up a monolith Emergent design Common restructuring patterns

In Legacy Systems: Transformation Strategies, leading IT and business architecture consultant William Ulrich presents a step-by-step, phased roadmap to legacy transformation that maximizes business value, while minimizing cost, disruption, and risk. Transformation strategies, organizing disciplines, techniques, and tools reduce the risks of deploying the component-based architectures you need to stay competitive while maximizing the business value of core systems that work.

Summary As a developer, you may inherit projects built on existing codebases with design patterns, usage assumptions, infrastructure, and tooling from another time and another team. Fortunately, there are ways to breathe new life into legacy projects so you can maintain, improve, and scale them without fighting their limitations. Purchase of the print book includes a free eBook in PDF, Kindle, and ePub formats from Manning Publications. About the Book Re-Engineering Legacy Software is an experience-driven guide to revitalizing inherited projects. It covers refactoring, quality metrics, toolchain and workflow, continuous integration, infrastructure automation, and organizational culture. You'll learn techniques for introducing dependency injection for code modularity, quantitatively measuring quality, and automating infrastructure. You'll also develop practical processes for deciding whether to rewrite or refactor, organizing teams, and convincing management that quality matters. Core topics include deciphering and modularizing awkward code structures, integrating and automating tests, replacing outdated build systems, and using tools like Vagrant and Ansible for infrastructure automation. What's Inside Refactoring legacy codebases Continuous inspection and integration Automating legacy infrastructure New tests for old code Modularizing monolithic projects About the Reader This book is written for developers and team leads comfortable with an OO language like Java or C#. About the Author Chris Birchall is a senior developer at the Guardian in London, working on the back-end services that power the website. Table of Contents PART 1 GETTING STARTED Understanding the challenges of legacy projects Finding your starting point PART 2 REFACTORING TO IMPROVE THE CODEBASE Preparing to refactor Refactoring Re-architecting The Big Rewrite PART 3 BEYOND REFACTORING—IMPROVING PROJECT WORKFLOWAND INFRASTRUCTURE Automating the development environment Extending automation to test, staging, and production environments Modernizing the development, building, and deployment of legacy software Stop writing legacy code!

This book constitutes the refereed proceedings of the 4th Conference on Extreme Programming and Agile Methods, XP/Agile Universe 2004, held in Calgary, Canada in August 2004. The 18 revised full papers presented together with summaries of workshops, panels, and tutorials were carefully reviewed and selected from 45 submissions. The papers are organized in topical sections on testing and integration, managing requirements and usability, pair programming, foundations of agility, process adaptation, and educational issues.