Real-time multipushdown and multicounter automata networks and hierarchies

Ph.D.William I. Grosk

Preliminary design of the redundant software experiment

The goal of the present experiment is to characterize the fault distributions of highly reliable software replicates, constructed using techniques and environments which are similar to those used in comtemporary industrial software facilities. The fault distributions and their effect on the reliability of fault tolerant configurations of the software will be determined through extensive life testing of the replicates against carefully constructed randomly generated test data. Each detected error will be carefully analyzed to provide insight in to their nature and cause. A direct objective is to develop techniques for reducing the intensity of coincident errors, thus increasing the reliability gain which can be achieved with fault tolerance. Data on the reliability gains realized, and the cost of the fault tolerant configurations can be used to design a companion experiment to determine the cost effectiveness of the fault tolerant strategy. Finally, the data and analysis produced by this experiment will be valuable to the software engineering community as a whole because it will provide a useful insight into the nature and cause of hard to find, subtle faults which escape standard software engineering validation techniques and thus persist far into the software life cycle

Applying Program Comprehension Techniques to Improve Software Inspections

: Software inspections are widely regarded as a cost-effective mechanism for removing defects in software, though performing them does not always reduce the number of customer-discovered defects. We present a case study in which an attempt was made to reduce such defects through inspection training that introduced program comprehension ideas. The training was designed to address the problem of understanding the artifact being reviewed, as well as other perceived deficiencies of the inspection process itself. Measures, both formal and informal, suggest that explicit training in program understanding may improve inspection effectiveness. The software technical review is a widely-recommended mechanism for software defect removal. Such reviews go by many names---inspections, Fagan-style inspections, code reviews, peer reviews, formal reviews---and exhibit significant variations among organizations [Fagan, Freedman, Gilb]. All such review methods rely on the self-evident notion that softwar..