The story of an internal SVC system developed by one engineer that leaves the company, and the team afterwards fails to deliver.

Regardless of its age, SVC is textbook legacy software because, more often than not, a question posed about the system, to any team member, results in the same answer: I don’t know. [...] The code may tell the what and the how, but it doesn’t tell the why.

In his Software Aging paper, David Parnas warns against putting software in the hands of developers who haven’t contributed to (and thus don’t understand) its design.

Our job is to explain, over and over, the meaning of our software. We must tell a story about what our software is, and what it’s expected to become. When understanding software, we tell that story to ourselves. When changing software, we tell that story to others. Software which is complex takes a long time to explain.

The death of a program happens when the programmer team possessing its theory is dissolved.