How does HDD store data?
Hard disk drives store data on one or more metal oxide platters. These platters spin at a rate of 3600-10,000 revolutions/minute, hold magnetic charges. A read-write head attached to an actuator arm actually floats on a cushion of air, 1-2 micro-inches (one millionth of an inch) above the surface of the platters. Data flows to and from these heads via electrical connections. Any force alters this process may cause data loss.
Ten years ago hard drives stored 40 Megabytes (MB) of data. Today’s hard drives store data up to 2000 gigabytes (GB) on a smaller surface. Increasing storage capacities amplify the impact of data loss. As more and more data is stored in smaller and denser areas, mechanical precision becomes crucial.
As a part of this advancing technology, the drive tolerance (distance between the read/write head and the platter where data is stored) is steadily decreasing. A slight nudge, an unstable power surge or a dust introduced into the drive may cause the head to touch the platter, resulting in a head crash, PCB burnt, bad sectors, etc. In some situations, the data residing in the area touched by the head may be permanently destroyed.
The current tolerance drives is 1-2 micro-inches (millionths of an inch). Comparatively, a speck of dust is 4-8 micro-inches and human hair 10 micro-inches. These sizes contaminants can cause serious data damage.