Hardware reliability engineering, for electrical and mechanical systems, is a mature discipline dating back to World War II.  Today, we can predict the reliability of modern systems with uncanny accuracy.  Software-based systems, however, are far more elusive.  Since the first attempt to predict software reliability in the 1960’s, engineers across all industries and academia have struggled to find the models and methods that would enable our ability to have confidence in our mission critical digital systems. In 2016, the IEEE published IEEE1633 – Recommended Practice for Software Reliability, which provided a consolidated, consistent, and practical framework for conducting software reliability engineering.