Comparing Coding, Testing, and Migration Costs for Two and Three Tier Client/Server Architectures

One can consider most end-user applications as consisting of three components: presentation, logic, and data. An architecture for a distributed, client/server system can be classified in terms of how these functions are split between software entities and where functions are located on a network. Although a virtually infinite number of possibilities exist for distributing and linking application components, research suggests most contemporary architectures can be defined in terms of a limited subset of alternatives. This paper focuses on issues related to the distributed logic scenario for two-tier and three-tier client/server architectures popular in implementing database transaction-oriented distributed systems. Organizations with portfolios of applications containing common and possibly reusable components would be interested in identifying the costs associated with coding, testing, and migrating (CTM) under different distributed architectures. Recent articles in practitioner literature have discussed the relative advantages and selection heuristics for these architectures,,,. However, these have not operationalized cost justification for choosing one alternative over the other. This paper begins to address this issue by offering formulations to assess CTM costs under specific scenarios. Research is underway to estimate the impact of this model on organizational decision making with regard to architecture choice