The authors discuss information transmission errors occurring between design engineers involved in software development and describe an interface design documentation system that can prevent them. The equivalence of human errors in software design and hardware manufacturing activities is established. The characteristics that must be included in an interface documentation system to prevent communication errors in software design activities, based on foolproofing principles that were identified for hardware manufacturing, are discussed. Utilizing these characteristics, an example of an interface documentation system for software products which control measuring equipment is presented. Its effects on the resultant number of communication errors between hardware and software engineers is subsequently experimentally evaluated.>

Two techniques are used to investigate software process human error prevention methods. One imports useful technologies from other engineering fields, e.g., the relations between operation methods and human errors were investigated for hardware production processes, and foolproofing process methods were systematized to prevent human errors. The other technique develops new methods based on quality feedback, where processes are improved through cause-effect analysis of empirical errors. The paper discusses establishing error-free software processes using these foolproofing and quality feedback methods.>

Approximately 700 errors in four commercial measuring-control software products were analyzed, and the cause-effect relationships of errors occurring during software development were identified. The analysis method used defined appropriate observation points along the path leading from cause to effect of a software error and gathered the corresponding data by analyzing each error using fault tree analysis. Each observation point's data were categorized, and the relationships between two adjoining points were summarized using a cross-indexing table. Four major error-occurrence mechanisms were identified; two are related to hardware and software interface specification misunderstandings, while the other two are related to system and module function misunderstandings. The effects of structured analysis and structured design methods on software errors were evaluated.>

A method of specifying effective testing regions for detecting software defects accompanying changes in external specifications is proposed. On the basis of a careful analysis of actual software defects, the concept of restriction elements is introduced, and it is shown that software defects resulting from external specification changes can be regarded as consisting of the incorrect addition or elimination of these restriction elements. These errors produce a response different from the specifications in certain input regions. A theorem concerning the regions influenced is presented, and examples showing the effectiveness of the method are given.>