Stability and volatility in the Linux kernel

Packages are the basic units of release and reuse in software development. The contents and boundaries of packages should therefore be chosen to minimize change propagation and maximize reusability. This suggests the need for a predictive measure of stability at the package level. We observed the rates of change of packages in Linux, a large open-source software system. We compared our empirical observations to a theoretical ´stability metric´ proposed by Martin. In this case, we found that Martin´s metric has no predictive value.