Chapter 12: Legacy Systems Integration

Chapter 12

Today's corporate environment is intensely competitive, and corporate leaders look to their information systems for an edge. Keeping up with technology while protecting the investment in existing applications is a constant challenge for most businesses. Many companies, in fact, most of the largest, do not have brand new systems that store, support, and manage their data. Upgrading to today's systems might not even be an option because of the dependency on old data and the inability to access it if a new system is purchased.

In addition to these challenges, companies are moving rapidly to give employees and customers access to business processes on the Internet in the form of suites of enterprise applications. This openness creates a demand to make the existing mission-critical business systems accessible through the Web.

In this chapter we will explore some of the issues and solutions in legacy systems integration. We will begin with a discussion about the challenges facing most legacy integration projects in an enterprise. We will then describe some common methods for accessing and controlling legacy applications from your new applications. Finally we will describe an approach for legacy systems integration using an XML-based layered architecture. The aim is to show you how XML can help position an organization's legacy systems for the future and tap those vast resources that at one time seemed as hidden away as a pharaoh's tomb.