Ensuring system and software reliability in safety-critical systems

Reliability growth models, formal specifications, testing, safety analysis have been proposed to address system and software reliability. This paper presents a technique, called ripple effect analysis, which is well known in software maintenance, for system and software reliability. This technique is useful to ensure that all the changes that need to be done are indeed changed after a software modification. It is different from regression test of which the purpose is to show that those parts that should not be changed remain unchanged after a software modification. We have used this technique at Guidant-CPI and found ripple effect analysis is an effective technique for ensuring system and software reliability in developing safety-critical systems.