Redundant arrays of independent components

Component-based software development has been advocated for a decade [63]. Recent developments in the software industry are posing to make it as easy to develop a distributable software component as it is to code a traditional software module [44, 47]. An abundance of inexpensive standard-binding software components is about to emerge. It will soon be possible to use redundant software components to enhance application reliability or to improve system performance without doubling or tripling component costs. Component integration cost, however, remains high. Before average software developers can take advantage of the coming abundance of low-cost software components, component integration techniques must be improved so that the benefits of adopting redundant components outweigh component integration cost.; Redundant Arrays of Independent Components (RAIC) is a component-based software development approach that enables groups of similar or identical distributed software components to provide dependable services to software applications [31]. The RAIC architectural style is a special architectural style designed to take advantage of redundant independent components in a systematic way. The RAIC style requires applications that use redundant components to access the services of the components via a special controller. The RAIC-style controller uses several RAIL techniques, such as component relation analysis, just-in-time component testing, and component state recovery, to provide the best possible services from the redundant components to the applications.; The RAIC approach eliminates direct interactions between the applications and the redundant components, thereby simplifying the interface logic of the applications. Furthermore, the RAIC supporting techniques are available to facilitate development of RAIC controllers. The RAIC approach, therefore, makes it easier and more effective to adopt redundant software components in software applications.; Software applications built on top of RAIC have better reliability, higher performance, or greater flexibility than applications built on top of individual components without redundancy.; The contributions of this dissertation are the identification of issues involved in achieving reliability-through-redundancy of software components, along with the development of an architectural style, a systematic approach and supporting techniques that address these issues.