Hard drives, by analogy

We are so blasé about hard drives and how they work. But the precision involved is astonishing:

The dimensions of the head are impressive. With a width of less than a hundred nanometers and a thickness of about ten, it flies above the platter at a speed of up to 15,000 RPM, at a height that’s the equivalent of 40 atoms. If you start multiplying these infinitesimally small numbers, you begin to get an idea of their significance.

Or, to give an amazing analogy:

Consider this little comparison: if the read/write head were a Boeing 747, and the hard-disk platter were the surface of the Earth:

• The head would fly at Mach 800
• At less than one centimeter from the ground
• And count every blade of grass
• Making fewer than 10 unrecoverable counting errors in an area equivalent to all of Ireland.

Wow. 

(via kottke)