Any software system, however securely written or precise the code is, is always susceptible to failure. These factors, such as the number of errors in the program or the mean-time for software failure, measure the program’s reliability. In order to meet more customer needs, current OSS products must be reliable. To measure these parameters, like the reliability of the software, we use different growth models called Software Reliability Growth Models. These models help us in determining the different reliability measures. Faults occur due to several reasons in software sometimes, it is the environmental factors. It can also be because of casual human behavior. Faults may also occur during the process of removal of previous faults. Whenever the code is changed, randomness in the software increases. We can calculate the optimal release time of a software product based on the calculated reliability measures, which have entropy also been considered. Finally, the user’s satisfaction level can also be considered.