Legacy Information systems typically form the backbone of the information flow within an organization and are the main vehicle for consolidating information about its business[1]. On one side, these systems are the fountainhead of critical information and procedures about the organisation’s business, while on the other one, as over years they undergo functional bricks addition in order to be in track with the evolving business rules, they finally result in large, complex, technologically out of date and costly maintainable systems.
In response to this, solutions have emerged from a simple system wrapping[2] with a convivial software approach, to a complete redevelopment from scratch. If the former solution doesn’t adress overloading problems, features inovation and costs reduction, the latter does not only increase failure risks but also disrupt operational and business environment during the cut-over phase.
Another way of coping with Legacy systems might be migration. We mean by migration, an upgrade of the legacy system with the reuse of much of its contents as far as implementation, design, hardware, specification and requirements are concerned. Legacy Information System migration is a major research field and encompasses common software engineering project issues, the “documentation-less” legacy system understanding, the target database population and last but not least the switch-over to the target system phase.
Approaches have already emerged in this field. For instance, the DARWIN[3] project from the university of California Berkeley introduced “Chicken Little” as an approach to incrementally migrate systems with the constraint of interoperatibility between legacy and target system. The MILESTONE project by it’s bing bang approach has introduced the butterfly Migration methodology[4], an alternative to chicken little’s phased interoperatibility which adress target database population. Business Process Management Technology can also been used for rewriting legacy systems as suggested in [5] with legacy systems mapping into business processes. From a technological or platform point of view, automated application modernization solutions like source code converters can also be used for legacy system migration in a context where the business rules are meant to remain untouched.
However, all these methodologies are either too-high level or adress the legacy problem from a fixed given angle. Moreover, the domain lack of tools that can provide lower level guidelines, migration activites and their workflow. Our thesis work would like then to be devoted to developing a tool ideally supported by a software, which aggregates knowledge from most of existing methodologies, encompasses crucial constraints like time and take in account both types of legacy system components (Executive, Management, Transactional IS), and business logics within the legacy system in order to provide meaningfull scheduled directions to people involved in migration projects. In more details, it’ll be in a first step about collecting enough information on existing migration therories and techniques; then a framework of questions depending on the type of IS will be setup, and presented to those in charge of migration in order capture as much consistent information on the legacy system as possible. Later, a collection of indices, matched with basics migration activities will be computed from the retrieved answers to the questions.
Of course, that’s not going to be an easy task at all. The first challenge there is that not only should the system be generic enough to cover most of IS types and businesses, but it should also be able to be adapted to a particular business context. The other point is about the creativity it will involve, in terms of exploring all kinds of systems, possible relationships or data exchange between them, and above all the contents of the survey to be conducted for capturing the legacy system caracteristics.
This proposition will be subjected to validation by school mentor, after what milestones will be identified and a timeline established for conducting the research project.
[1]: Legacy Information System Migration: A Brief Review of Problems, Solutions and Research Issues by Jesús Bisbal, Deirdre Lawless, Bing Wu, Jane Grimson.
[2]: I. Graham, ’Migrating to Object Technology’, Addison-Wesley, 1994.
[3]: DARWIN: On the Incremental Migration of Legacy Information Systems by Michael L. Brodie Michael - March 1993.
[4]: Legacy Systems Migration - A Method and its Tool-kit Framework by Bing Wu, Deirdre Lawless, Jesus Bisbal, D O’Sullivan, Ray Richardson Jane Grimson, Vincent Wade Broadcom Éireann Research.
[5]: A method for rewriting legagcy systems using business process management technology by Gleison Samuel do Nascimento, Cirano Iochpe, Lucinéia Heloisa Thom, Manfred Reichert.