Flexible Software Reliability Growth Models for Distributed Systems

Abstract

With the increasing demands on resources and skills needed to complete complex software projects, there is a steady move towards distributed working. Distributed software development is being made feasible owing to rapid advances in communication technologies. Distributed systems often involve development teams that are located across company sites, organizations, sectors and nations; as such there are special risks involved that are over and above the normal risks of software development. A distributed development project with some or all of the software components generated by different teams presents complex issues of quality and reliability of the software. The need is growing to estimate, risk assess, plan and manage the development of these distributed components and the final full system release. In this paper, an attempt has been made to compare Non Homogeneous Poisson Process (NHPP) based models in a distributed development environment. Proposed (NHPP) model assumes that the software system consists of a finite number of reused and newly developed sub-systems. The reused sub-systems do not consider the effect of severity of the faults on the software reliability growth phenomenon because they stabilize over a period of time i.e. the growth is uniform whereas, the newly developed sub-system does consider that. Fault removal phenomenon for reused and newly developed sub-systems have been modeled separately and is summed up to get the total fault removal phenomenon of the software system. The performance of SRGMs are judged by their ability to fit the past software fault data (goodness of fit) and to predict satisfactorily the future behavior of the software fault removal process (predictive validity)