If the recovery or remedial time is not incorporated in the reliability of a software module in a safety and time-critical integrated system operation, then a mere reliability index based on failure characteristics is simply not adequate and realistic. In deriving the probability density function (pdf) of the software availability, empirical Bayesian procedures will be used to employ expert engineering judgment through appropriate non-informative and informative prior distribution functions by employing various definitions of risk functions. It is emphasized that the usage of maximum likelihood estimators regardless of the extent of historical data is erroneous and misleading.