Something becomes a derivative work when excessive amounts of the source material structure comes from a copyrighted work. If you reverse engenear a program create a spec and have someone else code to that spec then copyright does not cover you.
You could create an original novel that was not a derivative work by taking once sentience from every book in a library and trying to create a meaningful work of art from it. Doing the same thing using a single book would probably not fly.
Yep, that's why the concept of clean-room reversing exists, to get around the derivative work concepts. It's not the only option, but it's probably the safest.
You could create an original novel that was not a derivative work by taking once sentience from every book in a library and trying to create a meaningful work of art from it. Doing the same thing using a single book would probably not fly.