A Software Reliability Growth Model for Three-Tier Client Server System

With the ever-increasing role that software is playing in our reallife systems, concern has steadily grown over the quality of the software products. In today’s life the computers are being used to monitor and control safety critical and civilian systems with a great demand for high-quality software products. So reliability is a primary concern for both software developers and software users. In literature many software reliability growth models have been proposed over the years to estimate and predict reliability of software products. But it is often very difficult for project managers and practitioners to determine which model is more useful in a particular domain and up to what extent. In this paper we propose a NHPP based software reliability growth model for three-tier client server systems. The present model composed of three layers of client-server architecture related to presentation logic, business logic and database stored at backend. Presentation layer contains forms or server pages which presents the user interface for the application, displays the data, collects the user inputs and sends the requests to next layer. Business layer, which provides the support services to receive the requests for data from user tier, evaluates against business rules, passes them to the data tier and incorporates the business rules for the application. Data layer includes data access logic, database driver(s), query engines used for communicating directly with the data store of a database. The model has been validated through standard dataset consists of software failure data on various projects released from the software reliability dataset and applying to a live commercial application.