Wrapping legacy systems for use in heterogeneous computing environments

Abstract With the advent and widespread use of object-oriented and client–server technologies, companies expect their legacy systems, developed for the centralized environment, to take advantage of these new technologies and also cooperate with their heterogeneous environments. An alternative to migrating legacy systems from the mainframe to a user-centered, distributed object computing, and client–server platform is to wrap the legacy systems on the mainframe and expose the interfaces of the legacy systems to the remote clients. The enabling middleware technologies such as Common Object Request Broker Architecture (CORBA), Component Object Model/Distributed Component Object Model (COM/DCOM), and Java RMI make the migration of the legacy systems to a heterogeneous distributed computing environment possible. In this paper, we present an approach and practical experience for integrating the legacy systems to a heterogeneous distributed computing environment by adopting the CORBA technology. It has been reported quite often that an approach like this will improve system maintainability, portability, and interoperability. We also illustrate this approach with an industrial project. The project is viewed as a reengineering effort where a centralized reengineering system is wrapped to operate in a heterogeneous distributed computing environment by leveraging CORBA technology. The reengineering approach is a combination of redesign and simple facelift. The resulting legacy integration architecture through the application of the approach is evaluated using the equality attributes proposed by Bass, Clements, and Kazman.