It strikes me that the Retina display is the other side of the coin to iOS. Meaning, iOS is the software and the screen is the hardware and that’s it. Those are the two sides to this coin. On a laptop or desktop computer you have three user interface components: the keyboard, the mouse, and the screen where you watch the user interface. On the iPad you have one user interface: the screen. And you touch and manipulate what is on the screen.