A CPS-conversion tool for software reliability composition

Estimates of reliability for software systems are usually derived from the system in its entirety. However, there is growing interest in estimating system reliability by composing the reliabilities of its components. Several approaches have been proposed and reported in the literature, and although component independence is a common element in most of the composition models, very little work exists to support design of such components in traditional software system development. One approach has shown that independence can be established by designing components according to specific guidelines, which include that the components are CPS (Continuation-passing style) compliant. This method has been considered infeasible in practice because of the difficulty of designing CPS compliant code in the usual procedural paradigm. This thesis proposes that for purposes of establishing software reliability, C programs can be transformed into CPS compliant format through the use of specific transformations. Once this is established for individual components, then it is possible to establish better measures for software system reliability. This research provides transformation templates to describe the CPS transformation rules and a tool to perform such automatic conversion of components into functionally equivalent components which are CPS compliant. The reliabilities of these components could then be composed without violating the underlying assumptions of the composition models. We present problems and solutions encountered in the tool design and development. We also include experimental evidence establishing confidence that our tool successfully produces CPS compliant code without altering the functionality of the original components.