Software Reliability

Another application of the probability relationships discussed in this chapter deals with software reliability. As indicated in Chapter 10, there are several models for calculating the reliability of software. The one selected for explanation in the last chapter was the so-called basic execution time model (BETM). In that model, the failure intensity (I) was decreasing linearly with the increasing number of failures/defects. Because failure intensity and failure rate are basically the same notion, we did not have the simple constant failure-rate situation. A new failure intensity had to be found as the number of failures/defects increased and were discovered. Knowing the new failure intensity then allowed us to utilize the Poisson distribution to calculate the reliability. For the case in which we were inquiring into the probability of exactly zero failures in time t, the Poisson reduced to the exponential case, as shown in the discussion in Section 10.5.5.

As suggested in the previous chapter, many other software reliability approaches depend heavily on probability relationships. For that essential reason, it is important, especially for the software systems engineer, to master the elements of probability theory.

Project Management Made Easy

Project Management Made Easy

What you need to know about… Project Management Made Easy! Project management consists of more than just a large building project and can encompass small projects as well. No matter what the size of your project, you need to have some sort of project management. How you manage your project has everything to do with its outcome.

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