In this paper I will discuss the development and use of the Continuous Hours of Operation (CHO) test which was developed for the Convex Division of Hewlett-Packard. My goal is to help readers with the practical aspects of developing a load test which can be used to help gauge and improve the reliability of a software system. I will briefly mention how we were unable to make much use of currently available software reliability frameworks, partially because of their deficiencies, and partially because of our inadequate knowledge of them. I knew enough about the theories to know that we did not have enough data to calculate a Mean Time to Failure metric; however, we were still successful in improving the reliability of our product and using the results of the CHO test as a release criterion.
