Evolution process for legacy system transformation

A legacy system is an application that was developed on older technology and is past its prime use, but is too critical to the business to disrupt. These applications usually run on mainframe computers and represent several millions of dollars and a few decades of investment. These systems are usually not flexible to change and have become deeply-rooted in the functionality of the business itself by housing a lot of important corporate data. The integration, usage and maintenance of legacy systems with emerging technologies, is a growing challenge to many American businesses. Especially now that re-engineering of the corporation has become more and more imperative to many businesses, support systems are needing to migrate to a more flexible, updated computing environment. More existing businesses are also migrating to Commercial Off-The-Shelf (COTS) software as companies downsize mainframe applications to smaller computers. While much of this software will not replace our legacy computing systems, they will be required to interface into these systems. What we need then is a way to integrate COTS with the existing systems.