Information systems that resist modification and don't support organizational requirements are a critical business problem. The authors present a step-by-step strategy for complete IS migration to a new environment and discuss the potential problems and alternatives that may arise in the process.

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.

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.

Design an enterprise solution from scratch that allows the migration of a legacy application. Begin with the planning and design phase and be guided through all the stages of selecting the architecture framework that fits your enterprise. Join Microsoft MVP Josh Garverick as he addresses all major areas of design and implementation—application, infrastructure, data, security, and deployment—while leveraging the power and tools of Visual Studio Team Services (VSTS) to bring DevOps to the forefront. With an emphasis on principles and best practices of enterprise design, you will discover how to recognize existing patterns within the legacy platform and to identify potential risks, bottlenecks, and candidates for automation. What You’ll Learn Accurately and completely capture baseline information about a legacy system Leverage enterprise patterns for constructing next-generation platforms in the cloud Design, plan, and implement deployment pipelines to enable continuous delivery Identify and implement cloud-based platform components to reduce total cost of ownership Understand testing and validation: iterative component authoring, monitoring, deployment, and performance Price and perform capacity planning for cloud-based infrastructure and workloads Who This Book Is For Enterprise architects and IT professionals who are required to keep legacy applications relevant in today’s cloud-first world

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!

How do you detangle a monolithic system and migrate it to a microservice architecture? How do you do it while maintaining business-as-usual? As a companion to Sam Newman’s extremely popular Building Microservices, this new book details a proven method for transitioning an existing monolithic system to a microservice architecture. With many illustrative examples, insightful migration patterns, and a bevy of practical advice to transition your monolith enterprise into a microservice operation, this practical guide covers multiple scenarios and strategies for a successful migration, from initial planning all the way through application and database decomposition. You’ll learn several tried and tested patterns and techniques that you can use as you migrate your existing architecture. Ideal for organizations looking to transition to microservices, rather than rebuild Helps companies determine whether to migrate, when to migrate, and where to begin Addresses communication, integration, and the migration of legacy systems Discusses multiple migration patterns and where they apply Provides database migration examples, along with synchronization strategies Explores application decomposition, including several architectural refactoring patterns Delves into details of database decomposition, including the impact of breaking referential and transactional integrity, new failure modes, and more

Migrating to the Cloud: Oracle Client/Server Modernization is a reference guide for migrating client/server applications to the Oracle cloud. Organized into 14 chapters, the book offers tips on planning, determining effort and budget, designing the Oracle cloud infrastructure, implementing the migration, and moving the Oracle cloud environment into production. Aside from Oracle application and database cloud offerings, the book looks at various tools and technologies that can facilitate migration to the cloud. It includes useful code snippets and step-by-step instructions in database migration, along with four case studies that highlight service enablement of DOS-based applications, Sybase to Oracle, PowerBuilder to APEX, and Forms to Java EE. Finally, it considers current challenges and future trends in cloud computing and client/server migration. This book will be useful to IT professionals, such as developers, architects, database administrators, IT project managers, and executives, in developing migration strategies and best practices, as well as finding appropriate solutions. - Focuses on Oracle architecture, Middleware and COTS business applications - Explains the tools and technologies necessary for your legacy migration - Gives useful information about various strategies, migration methodologies and efficient plans for executing migration projects