Hard Drive Adaptive Variables
Two absolutely identical devices never exist; some of their parameters differ by all means, and in spite of the fact that hard drives are very precise devices, a disorder of parameters inevitably occurs at their mass production. In modern drives with their huge density of record, the slightest deviations in the sizes of details or in amplitudes of signals can lead to deterioration of properties of a product, errors occurrence, up to complete loss of its workability. Therefore all the modern hard disk drives go through an individual adjustment at manufacturing. During this procedure, the electric signal parameters that provide better efficiency of the device are selected. This adjustment is carried out by the firmware at technological scanning of the surface, during which the adaptive variables containing the information about features of the concrete hermetic block are created. The adaptive variables remain on magnetic disks in a service zone or in non-volatile memory on a controller board.