JSE_V5_N2_RP1 Shaik Mohammad Rafi Shaheda Akthar Journal on Software Engineering 2230 – 7168 5 2 1 9 Imperfect-Debugging, Non-Homogeneous Poisson Process, Software Reliability, Warranty Cost Reliability is one of the important quality measures of software product. Testing is one important phase in software development life cycle whose intention is to find the bugs present in the software product. A mathematical model which describes the software testing in software development cycle is termed as software reliability growth model. Past few decades many software reliability growth models were proposed. Estimating the accurate release time of software is an important challenging issue of software Development Company. If the software product is released early, it contains more errors and makes software to be less reliable, whereas late release will increase the development cost. It is observed that more than half of the total development cost is concentrated during the maintenance phase. Estimating the reliability and accurate development cost of software product by software reliability growth model at maintenance phase is an important issue. Warranty is defined to be an agreement between the customer and vendor of the software to provide the extra protection to the product. Several papers have concentrated on optimal release time by considering the warranty cost. All early proposed NHPP warranty cost models considered a perfect-debugging software reliability growth model while estimating the software maintenance cost. But it was observed that, the software product is influenced by several factors like environment, resources and nature of the faults during the operational phase. In such circumstances it is quite not right to consider a perfect NHPP software reliability growth model in operational phase. In this paper the authors propose an imperfect debugging software reliability growth model by combining the cost and reliability at a given warranty period to estimate the optimal release time of software product. October - December 2010 Copyright © 2010 i-manager publications. All rights reserved. i-manager Publications http://www.imanagerpublications.com/Article.aspx?ArticleId=1329