On Faults and Faulty Programs

MILI, ALI; FRIAS, MARCELO; JAOUA, ALI

Marienstatt

Conferencia; 14th International Conference, RAMiCS 2014; 2014

A fault is the feature of a program that precludes it from being correct; while this definition may sound clear-cut, it leaves many details unspecified. An incorrect program may be corrected in many dif- ferent ways, involving different numbers of modifications. Hence neither the location nor the number of faults may be defined in a unique man- ner; this, in turn, sheds a cloud of uncertainty on such concepts as fault density, and fault forecasting. In this paper, we present a more precise definition of a program fault, that has the following features: It recog- nizes that the same incorrect program behavior may be remedied in more than one way; it recognizes that removing a fault does not necessarily make the program correct, but may make it is less incorrect (in a sense to be defined); it recognizes that isolating a fault in a program is based on implicit assumptions about the remaining program parts; it identi- fies instances where a fault may be localized in a program with absolute certainty.