Presentation
Legacy Modernization Using Service Oriented Architecture

While modernizing/migrating complex legacy systems, we face challenges in all the three areas of Technology, Process and People. The Technology challenges arise because of the fundamental difference in J2EE/.NET Technologies and Mainframe Technologies like CICS, COBOL or AS/400 based systems. We face process challenges because the legacy systems have been developed not with a clearly defined process supported by documentation but building strongly coupled and less cohesive components on top- of each other that has lead to spaghetti code and maintenance nightmare. On the People front, there is a resistance from the developers (who have spent almost their entire life working on these systems to migrate to new technologies) since that requires stepping out of their comfort zones which in turn leads to insecurity of losing jobs. In addition to that there is the challenge of the steep learning curve.

Keeping all these problems in perspective, it is therefore not possible to use a big-bang approach while modernizing complex legacy systems, i.e. changing overnight the technologies, processes and people s mindsets. Service Oriented Architecture comes to the rescue for tackling such problems. On the technology front, it helps create a service layer of abstraction on top of the existing legacy components (e.g. a CICS Transaction written in COBOL can be exposed as a service) which can then be used by a J2EE or .NET Layer. On the process front it helps streamline/reengineer the Business Processes by reusing the old services that uses legacy technologies and write additional services using new technologies thereby leveraging the advantages of both. And through this approach, the end-user will experience no downtime and not realize whether the services come from Legacy components or J2EE/.NET Components and then the legacy components can be slowly replaced without changing the interface. Lastly, on the people side, since there will still be requirements for legacy skills, there will be no fear of losing jobs or stepping out of comfort zones.

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