Patent ID: 6373649
Filing Date: 2002-04-16
Classification: G11B

Abstract:
In a disc drive head-disc assembly having an array of discs adjacent an actuator supporting a maximum number of heads in a fully populated configuration and a reduced number of heads in a depopulated configuration, each head disposed at a unique head position of the actuator, a method for determining a configuration of the head-disc assembly, comprising steps of:(a) determining a first impedance at a first selected head position having a first head when the head-disc assembly is fully populated, but not when the head-disc assembly is depopulated; (b) identifying the configuration of the head-disc assembly as fully populated when the first impedance is less than a predetermined threshold; and (c) determining whether the head-disc assembly is depopulated or there is an error in the first head when the first impedence is more than the predetermined threshold value by: (c1) determining a second impedence at a second selected head position having a head when the head-disc assembly is fully populated and not having a head when the head-disc assembly is depopulated; (c2) identifying the configuration of the head-disc assembly as depopulated when the second impedance is greater than the predetermined threshold; and (c3) declaring an error in the first head when the second impedance is less than the predetermined threshold.