How hard drive works inside

This video shows how hard drive works while you are doing something on your computer. Watch this video and read the following paragraph from Wikipedia and imagine if you shake/bang your laptop or desktop while operating(while disk is spinning at at the speed of 5400 r.p.m or 7200 r.p.m or more.)

"Hard drives have a mostly sealed enclosure that protects the drive internals from dust, condensation, and other sources of contamination. The hard disk's read-write heads fly on an air bearing which is a cushion of air only nanometers above the disk surface. The disk surface and the drive's internal environment must therefore be kept immaculate to prevent damage from fingerprints, hair, dust, smoke particles and such, given the sub-microscopic gap between the heads and disk." source: Wikipedia

Tag: youtube, hardware, computer