I think you're taking the phrasing too literally. When we say software rots, we're not just talking about the bits that make up a program, but also its interfac

I think you're taking the phrasing too literally. When we say software rots, we're not just talking about the bits that make up a program, but also its interface with its environment, and the knowledge about it in people's brains. Both those connections are indeed subject to drift/evaporation/entropy. The two failure modes you mentioned are symptoms of that underlying evaporation. I spend a lot of time thinking about this (http://akkartik.name/about http://akkartik.name/about), but lately I try to steer clear of metaphors, because they're so often clear in my mind but utterly opaque to someone else's. So, I don't care what we call it, as long as more people try to fix the problem.