Class Diversity Support in Object-Oriented Languages

摘要

The authors start with a general approach to introducing software fault tolerance211u001e(SFT) into object-oriented (OO) systems and proceed in two directions. The first 211u001eone is the use of SFT schemes within standard OO languages. The authors' 211u001eintention is to thoroughly analyze all engineering steps which allow diversity to 211u001ebe introduced in systems programmed in these languages. Some new general problems 211u001eare spotted and discussed as well. The second direction is dealing with version 211u001econcurrency and distributedness in a general way. The authors investigate 211u001eproviding SFT by class diversity, which is the most general way of designing 211u001ediverse software in OO systems. The authors concentrate on N-version programming 211u001eand give an exhaustive discussion of this approach. The authors' intention is to 211u001ediscuss the use of N-version programming in OO terms and to outline all novelties 211u001earising from this. One of the conclusions the authors have arrived at is that, 211u001egenerally speaking, the entire states of version objects should be compared to 211u001edetect and mask the faulty one. The authors propose unifying in one component 211u001efeatures dealing with adjudication and faulty object recovery because these 211u001efunctionalities have a lot in common.