Somewhat off topic, but while we're talking about drives:
We put millions of transistors on a chip. Millions of photodetectors (pixels) in your phone's camera, a million pixels on it's display. Yet our hard drives have ONE sensor that swings back and forth on a mechanical arm?!?! Why the heck isn't the read/write head a strip, with a few thousand "pixels", so it can read any sector as the platter spins beneath it, without swinging the heads back and forth? That would eliminate seek time.
If needed, you could move the strip back and forth a thousandth of an inch to align a head with one of it's four tracks. That'd be a lot quicker that moving the head a full inch as they do now.
So presumably there is some good reason that can't be done. Still, an additional arm exactly like the existing one, but on the opposite side of the platter, would cut rotational latency in half and increase throughout up to 100%. Seems like an easy win.