Book Image

Modernizing Legacy Applications to Microsoft Azure

By : Steve Read, Larry Mead
Book Image

Modernizing Legacy Applications to Microsoft Azure

By: Steve Read, Larry Mead

Overview of this book

Organizations have varying circumstances, objectives, and prerequisites when contemplating a hyper-scale cloud solution transformation to a platform such as Azure. Modernizing Legacy Applications to Microsoft Azure uncovers potential scenarios and provides choices, methodologies, techniques, and prospective possibilities for transitioning from legacy applications to the Microsoft Azure environment. You’ll start by understanding the legacy systems and the main concerns regarding migration. Then, you’ll investigate why distributed architectures are compelling and the various components of the Azure platform needed during migration. After that, you’ll explore the approaches to modernizing legacy applications and the Rs of modernizing (i.e., rehost, refactor, rearchitect, and retire). You’ll also learn about integration approaches and potential pitfalls. By the end of this book, you’ll be well equipped to modernize your legacy workloads while being aware of pitfalls and best practices.
Table of Contents (18 chapters)
1
Part 1: Legacy Estate Options
3
Chapter 2: Strategies for Modernizing IBM and Unisys Mainframes
6
Part 2: Architecture Options
10
Part 3: Azure Deployment and Future Considerations

How did most mainframe applications become monoliths?

Monolithic systems are common on IBM mainframes for a number of reasons:

  • Mainframes have been around for 50+ years and can still run applications developed 50+ years ago
  • Common programming languages such as Common Business Oriented Language (COBOL) and Programming Language/I (PL/I) allowed for procedural code to be easily developed
  • Mainframe tools such as Customer Information Control System (CICS) and Information Management System (IMS) allowed procedural code to be developed in an environment that could scale up easily
  • Mainframe hardware has become more powerful over time to keep pace with the performance demands of monolithic applications

With these factors in mind, it is easy for monolithic systems to grow to over 10 million lines of interdependent source code, making the task of modernizing look very daunting and costly.

What about iSeries and Enterprise UNIX?

Monolithic systems are not unique...