Black boxes are never patentable. The concept of patents is that you reveal exactly how your process works and you get a limited monopoly on the totally new and non-obvious bits of your process for the public benefit. It always matters how the process works inside.

I shouldn't have used the term "black box". Assume it's a pair of crystal clear boxes, and inside one is a beautiful, novel arrangement of gears and camshafts which I have painstakingly documented in patent A, and inside the other is a run-of-the-mill laptop, running software that I have painstakingly documented in patent B.

Both devices perform the same function. It's something no device has ever done before, and has substantial practical uses. Let's say it can accurately predict when your in-laws will next visit.

What makes patent A valid while patent B is "harmful to innovation"? Or are they both "software patents"?