OPTIMAL COMPONENT SELECTION APPROACH FOR FAULT-TOLERANT SOFTWARE SYSTEM UNDER CRB INCORPORATING BUILD-OR-BUY DECISION

Application Package Software (APS) has emerged as a ready-to-use solution for the software industry. The software system comprises of a number of components which can be either purchased from the vendor in the form of COTS (Commercial Off-the-Shelf) or can be built in-house. Such a decision is known as Build-or-Buy decision. Under the situations wherein the software has the responsibility of supervising life-critical systems, the inception of errors in software due to inadequate or incomplete testing, is not acceptable. Such life-critical systems enforces upon meeting the quality standards of the software as unforbiddenable. This can be achieved by incorporating a fault-tolerant design that enables a system to continue its intended operation rather than failing completely when some part of the system fails. Moreover, while designing a fault-tolerant system, it must be apprehended that 100% fault tolerance can never be achieved and the closer we try to get to 100%, the more costly the system will be. The proposed model shall incorporate consensus recovery block scheme of fault tolerant techniques. Through this paper, we shall focus on build-or-buy decision for an APS in order to facilitate optimal component selection thereby, maximizing the reliability and minimizing the overall cost and source lines of code of the entire system. Further, since the proposed problem has incompleteness and unreliability of input information such as execution time and cost, hence, the environment in the proposed model is taken as fuzzy.