A hard disk, storing the data in a way memagnetkan film'' ferromagnetic'' material on the disc. Sequence changes direction pemagnetan will represent binary data bits. Data read from the disk by detecting the change pemagnetan. User data is encrypted using the encoding scheme that determines how data is displayed again by changing magnetic fields. Diagram of the main components of hard disk record pemagnetan single bit on a 200 MB disc (recording shown using CMOS-MagView).
Generally, hard disk consists of a shaft (spindle) that keep the round disk (platter) where the data is stored. The discs are made of non-magnetic material, usually aluminum alloy, glass, or ceramic coated a thin layer of magnetic material as thick as 10-20 nanometers are then coated with a protective outer carbon. For comparison, a thick sheet of standard paper is 0.07 to 0.18 millimeters.
Modern hard disc on the disc rotates ranging from 4,200 ppm to energy-saving light devices to 15,000 ppm for high-performance servers. The first-generation hard disc rotates at a speed of 1,200 ppm. The next generation using a speed of 3,600 ppm and in general is currently working on the 5400-7200 ppm.
Information is read and written to the disk rotates through reader-write (disk read and write heads) are working very close (about 10 nanometers) above the surface of the magnetic disk. Readers-write is used to detect and modify the magnetization media underneath.
In modern disc-wrote one reader mounted on the arm bertuas for each disk surface. A reader-arm move bertuas write like a bow across a rotating disc, allowing each reader-write access almost the entire surface of the disc. The arm is moved using arm propulsion system motoran rolls. The old model's hard drive write data remains in bits per second, so that each flow has the same data size. The latest model (since the 1990s) using the recording system beet area (zone bit recording) that can increase the speed of writing to the deepest area of the disc outer area. Thus the data stored in the outer areas will be more.
In modern discs, the small size of the magnetic field endanger kemagnetannya area of possible loss due to thermal effects (superparamagnetism). To overcome this, the dish coated with two parallel magnetic layers, separated as far as 3 atoms using non-magnetic materials ruthenium and two layers are magnetized direction bersebrangan mutually reinforce each other. Another technology used to overcome thermal effects that allow for high density recording was first made in 2005 and in 2007 the technology has been widely used in hard disk.
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