System Evolution in the Intelligent Enterprise: An Historical Case Study of VISA's Transaction Processing Systems

Intelligent enterprises need systems which evolve well. Systems will increasingly be expected to evolve to meet users' changing needs, and predicting user demand is becoming more inexact. System engineers need to understand why some systems evolve well and put this knowledge into practice. Lessons learned from the evolution of actual systems should be incorporated into system design and development processes to equip the system engineer to meet this challenge. This paper discusses a case study of the technological evolution of VISA's credit card transaction processing systems. It identifies key principles which were successfully applied to enhance system evolution. The paper discusses observations concerning how generic properties (the illities) relate to one another and how they were achieved in VISA's system design. Related issues of system platforms and component coupling which affect system evolution are also addressed.