Software lifetime and its evolution process over generations

It is noted that the software evolution process does not end at the death of an individual software system but usually continues over generations through being replaced by newly built software. To explore this research topic, the authors conducted a survey, collecting data of software lifetimes, replacement practices, and factors of replacement. They report the results of the survey and discuss some possible long-range strategies for software life cycle planning and control based on the findings. The following issues related to such strategies are discussed; management by lifetime characteristics, monotonicity of size growth, and reuse