A Systematic Framework for Modernizing Legacy Application Systems

Researchers estimate that 180 - 200 billion lines of legacy code are still in use today. Legacy application system modernization is driven by an organization's desire to remain agile to changes, reduce operating costs and gain a clearer understanding of their application system infrastructure. In this paper we present a systematic modernization framework for legacy systems. Our framework considers the application code, information system and infrastructure as distinct entities which can be modernized independently. As a result, our approach can be applied sequentially to a single program module, or in parallel across multiple program modules. We validate our framework through an industrial case study involving a large, multinational financial services institution. Our case study results show that through modernization the organization reduced its cost to the sponsoring users by 80%, lines of code by 89%, operational complexity by 99%, and achieved an estimated 66% reduction in the man-hours required for time to market using the new application functions.