If you think that "Identify the inputs and outputs and reverse engineer it which isn't hard" is all that's needed to re-create some bespoke piece of software th

If you think that "Identify the inputs and outputs and reverse engineer it which isn't hard" is all that's needed to re-create some bespoke piece of software then I hope you will never-ever have the chance to put this in to practice for this sort of safety-critical stuff. "Oh yes, we missed that one output that only happens under these specific conditions and now the train crashed – oops!"