Software safety and program slicing

Describes a novel application of program slicing to two issues of software safety: functional diversity and the validation and verification of safety-critical components. Software quality assurance auditors are faced with a myriad of difficulties, ranging from inadequate time to inadequate CASE tools. One particular problem is the localization of safety-critical code that may be interleaved throughout the entire system. Once this code is located, its effects throughout the system are difficult to ascertain. A method is presented that uses program slicing to mitigate these difficulties in two ways. First, it is shown that program slicing can be used to locate all code that contributes to the value of variables that might be part of a safety-critical component. Second, it is shown that slicing-based techniques can be used to validate functional diversity, i.e. that there are no interactions of one critical component with another critical component and that there are no interactions of noncritical components with the safety-critical components