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DARWIN: On the Incremental Migration of Legacy Information Systems

Stonebraker, Michael
Brodie, Michael L.
Technical Report Identifier: S2K-93-25
No created date null

Abstract: As is painfully evident today, the deterioration of the transportation, education, and other national infra- structures negatively impacts many aspects of life, business, and our economy. This has resulted, in part, when responses to short term crises discourage investing in infrastructure enhancement and when there are no effective information system (IS) infrastructure that has strong negative impacts on ISs, on the organizations they support, and, ultimately, on the economy. This paper addresses the problem of legacy IS migration by methods that mediate between spectrum of supporting methods for migrating legacy ISs into a target environment that includes rightsized hardware and modern technologies (i.e., infrastructure) such as client-server architecture, DBMSs and CASE. We illustrate the methods with two migration case studies of multi-million dollar, mission critical legacy ISs. The contribution of this paper is a highly flexible set of migration methods that is tailorable to most legacy ISs and business contexts. The goal is to support continuous, iterative evolution. The critical success factor, and challenge in deployment, is to identify appropriate portions of the IS and the associated planning and management to achieve an incremental migration that is feasible with respect to the technical and business requirements. The paper concludes with a list of desirable migration tools for which basic research is required. The principles described in this paper can be used to design future ISs and an infrastructure that will support continuous IS evolution to avoid future legacy ISs.