Evaluation of software availability for the imperfect software debugging model
To evaluate the software-related measure such as the first passage time and software availability, we consider in this paper an imperfect software debugging model incorporating two types of fault, one being easily detected and the other difficult to detect. When a software failure occurs, the fault that causes the failure either is removed from the fault contents or still remained in the system even after the debugging is completed. In this sense, the debugging model is referred to as an imperfect model. In this paper, we first define the transition probabilities of the debugging process and use it to derive several parameters of interest measuring the software performance, including the expected numbers of perfect debuggings. The availability function of a software system, which is defined as the probability that the software is in a working state at a given time, is also derived. We assume that the length of time necessary for debugging the failure is random in all evaluations. Numerical examples are given to illustrate the methods discussed.
software debugging model transition probability imperfect debugging markov process fault removals