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To reach the space or the data from each position on the rounded data slices, in hard drives to play together two engines and propulsion units: The drive, which enables the read-write head like a record needle and the rotary engine, with the data slices high velocity about the spindle axis rotates.
These
In the latter it is a small electric motor which is mounted either between or among the data discs in the spindle. The high speed that he generates is responsible for two effects:
Firstly, the speed can be used to access the data. The disk rotates faster, the read-write head resting on the course faster and can read data faster.
On the other hand is caused by the rotation of an air stream and thus a force sufficient to keep the read-write head at close range (~ 10-20nm!) Over the plate.
speeds that are common today are moving for different applications on different scales: Laptop hard disks to be low power and small (usually 2.5 ") running at 4,200 to 7,200 rev / min (U = revolutions), in standard desktop PCs are usually 3.5 "hard drives at speeds between 5,400 'and 10,000' U / min blocked. Only in high-performance computers and servers, this is still of speeds up to 15,000 "U / min exceeded.