Working of an Hard Disk Essay

571 WordsMar 6, 20143 Pages
Hard Disk Working A hard disk uses rigid rotating platters. Each platter has a planar magnetic surface on which digital data may be stored. Information is written to the disk by transmitting an electromagnetic flux through an read-write head that is very close to a magnetic material, which in turn changes its polarization due to the flux. A typical hard disk drive design consists of a central axis or spindle upon which the platters spin at a constant rotational velocity. The associated electronics control the movement of the read-write armature and the rotation of the disk, and perform reads and writes on demand from the disk controller. The sealed enclosure protects the drive internals from dust, condensation, and other sources of contamination. Contrary to popular belief, a hard disk drive does not contain a vacuum. Instead, the system relies on air pressure inside the drive to support the heads at their proper flying height while the disk is in motion. Modern drives include temperature sensors and adjust their operation to the operating environment. The filter also allows moisture in the air to enter the drive. Very high humidity year-round will cause accelerated wear of the drive's heads. Due to the extremely close spacing of the heads and disk surface, any contamination of the read-write heads or disk platters can lead to a head crash a failure of the disk in which the head scrapes across the platter surface, often grinding away the thin magnetic film. Head crashes can be caused by electronic failure, a sudden power failure, physical shock, wear and tear, or poorly manufactured disks. Normally, when powering down, a hard disk moves its heads to a safe area of the disk, where no data is ever kept. However, especially in old models, sudden power interruptions or a power supply failure can result in the drive shutting down with the heads in the data zone, which

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