Software Re-Engineering for Real : Legacy Information Systems

Reference:  Legacy Information System

                  By George Bakehouse & Tony Wakefield

A legacy information system (LIS) represents a massive, long-term business  investment. Unfortunately, such systems are often brittle, slow, and non-extensible. Capturing legacy system data in a way that can support organizations into the future is an important but relatively very difficult and expensive. Generally the system which developed in 60’s, 70’s and 80’s are considered as legacy system but these systems are still running in businesses and more  reliable, secure and have lot of priceless information about the business. However owners of these systems are unable to compete in the market due to restricted characteristics.

Organization which are using legacy systems, are unable to invest money on new  project and  technologies, as they have to invest a lot in maintaining legacy  systems. In other hand replacement for legacy systems also very high risk and  high investment project, as they have hold valuable business information with  them. The decision to replace the existing legacy systems is derived by number of  factors such as lack of openness and non-extendable characteristics, they  doesn’t allow to integrate with new systems, and very difficult to adopt new  changes as they have been  deteriorated by continues changes and lack of documentation leads to maintenance programmers to spend more on understanding the system. To be an competitor in market, owners of these  systems should update their systems to meet the new challenges and demands, otherwise they will be affected negatively. Mergers and acquisition of organizations have also impacted on development of legacy system, M&As can result in the need to integrate two or more incompatible legacy systems or to upgrade the systems in the dominant partner to meet the requirements of the new acquisition which cause further replacement of legacy  systems. It is always better to replace the legacy systems when they are no longer productive or beneficial, replacement will give more benefit such as reduced   maintenance costs, improved productivity, and reduced number of staff dealing with system, reduced training time and ability to compete effectively.  Software re-engineering is the methodology to update / replace the legacy systems in more efficient way without lost of information data, document the system by understanding the code and then design and develop the new system with the data gathered. But still it costs a lot as; it is difficult and expensive to find people who are excellent in old technologies as well as newer.

Thanks
TS