How Fast Is Hard Drive Head?

A 7,200 RPM hard drive head moves over the platters at 108 km/h — just 10 nanometres above the disc surface. That's like a 747 flying 3 cm above the ground — except sustained continuously, every second the drive is on.

Hard drives store data using magnetic regions just 25 nanometres across — over a thousand times smaller than the wavelength of visible light.

• Same as freeway driving
• Like a 747 flying 3 cm above the ground