LACE Frameworks and Technique -- Identifying the Legacy Status of an Information System from the Perspectives of its Causes and Effects

One of the most difficult challenges arising from dealing with so called legacy systems is how to identify and determine the ‘legacy status’ of such a system, where no commonly accepted definitions existed until very recently. This paper tackles this problem. It researches into the concept of legacy status and related issues, and aims at developing a set of frameworks and an associated technique, which can be used by management to identify legacy status accurately in a current or a planned business information system. This paper first presents a definition of the concept of ‘legacy status’ with a 3-dimensional model. It then discusses the LACE frameworks and technique, which can be used to assess legacy status from the cause and effects’ perspectives. It also outlines a method for applying these LACE frameworks and the technique with a mathematical model and metric so that the legacy status of a legacy system can be calculated. This paper describes a novel and practical way to identify legacy status of an information system, and has possibly pointed out a new direction for research in this area.