Disk drive including n-current preamplifier for generating n-independently controlled write currents

Abstract

A disk drive comprising a plurality of recording surfaces and plurality of associated heads is disclosed employing a n-current preamplifier for generating n independently controlled write currents. For example, the n-current preamplifier may be employed during manufacturing of the disk drive to simultaneously write servo sectors to all of the recording surfaces in a “bank servo write” mode. The n-current preamplifier comprises an input for receiving a plurality of current-setting control signals corresponding to the plurality of heads, and a plurality of signal-to-current converters for converting the current-setting control signals into a plurality of write currents for the heads, wherein each write current has a magnitude that is independently controlled by a respective one of the current-setting control signals. The optimal write current for each head is determined during a calibration mode wherein a test pattern is written to and read from the disk to generate a quality metric indicative of the quality of the write current setting. Several write current settings are tested for each head, and the write current that generates the best quality metric for each head is used to simultaneously write the servo sectors to the recording surfaces.