Effect of fault distribution and execution patterns on fault exposure in software: a simulation study

Execution patterns and fault distribution characteristics of a program will affect the failure process and thus reliability estimates. The failure process of a software system is influenced by many factors, and traditional software reliability engineering has found it difficult to isolate the effect of each individual factor. A simulation approach is used to investigate the effects of fault distribution, execution pattern and program structure on software reliability estimates. A reliability simulation environment (RSIM) is extended by introducing variable fault distribution patterns in its code generation phase. Flow control points allow varying the execution frequency of different parts of a program. The simulation results show that fault distribution patterns and execution patterns have dramatic effects on fault exposure rate. If the fault distribution is non‐uniform, a non‐uniform code execution exposes faults more efficiently and effectively than uniform execution. Results also show that the structure of a program affects fault exposure rate and testing time required. Copyright © 2000 John Wiley & Sons, Ltd.