Software reliability modeling (tutorial)
Amrit L. Goel · 1986
There are a number of views as to what software reliability is and how it should be quantified. Some people believe that this measure should be binary in nature so that an imperfect program would have zero reliability while a perfect one would have a reliability value of one. This view parallels that of program proving whereby the program is either correct or incorrect. Others, however, feel that software reliability should be defined as the relative frequency of the times that the program works as intended by the user. This view is similar to that taken in testing where a percentage of the successful ewes is used as a measure of program quality. According to the latter viewpoint, software reliability is a probabilistic measure and can be defined as follows: