1. The general issue of software reliability

1.1 What is software reliability?

According to the UTE (Union technique de l'électricité), the reliability of software, or more generally of a system, refers to its ability to carry out its mission under given environmental conditions and for a given period of time. Reliability thus characterizes the confidence that the user can place in the service provided by a system.

In this article, the reference definition of software reliability is: "The probability of a software product performing the set of functions specified in its reference document, in a given environment and for a given operating time". This is a reliability definition, which can be evaluated by a mathematical expression, and is therefore much more restrictive than the definition of software...