You missed my point. Absolutely, channel & HDC speeds have come up dramatically with smaller geometries. Ten years ago, 10Mhz NRZ bit rates were the norm, today's fastest (and most expensive) channels are in the 400Mhz range. My point was that it's not unusual for a slower rpm drive to have the same transfer rate as a higher rpm drive, simply because drive vendors sometimes spin the drive faster than the channel can handle. They basically trade off some capacity in order to be able to advertise the big spin speed number.
I know, you're skeptical, and to convince you, I could walk through the equations with you for bit rate at a given radius, rpm, and bit density, if I had the time. But the jist of it is that it's not hard at all to spin faster than your silicon can handle, and I know from first hand experience that it's not unusual to design drives this way. |
