" Who designed the circuit? What do they say?” “They’re all either long retired or long dead. And they didn’t expect the programs to last more than a few years anyway. So there’s no documentation. It was just a bunch of geeks standing around a lab bench, trying to figure things out. No one remembers the exact details. No one is smart enough to work it out again backward. And "

― Lee Child , Night School (Jack Reacher #21)