Reduced head population detection in a disc drive
AssigneeSeagate Technology LLC
InventorsJohn E. Moon, Timothy T. Walker, Paul F. Kusbel, Robert Matousek
Life of this patent
Estimating the term…
Abstract
An apparatus and method for determining the configuration of a disc drive head-disc assembly (HDA). The HDA includes an array of rotatable discs and an actuator adjacent the discs, with the actuator supporting a maximum number of heads in a fully populated configuration and a reduced number of heads in a depopulated configuration. Each head is disposed at a unique head position. A servo circuit determines an impedance of a selected head position having a head when the disc drive is fully populated but not when the disc drive is depopulated. The servo circuit identifies this configuration of the HDA in relation to the determined impedance, and initializes the drive accordingly.
Claims16
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 the configuration of the head-disc assembly, comprising steps of:
- (a) prior to spin-up of the discs, determining a first impedance of a first write element at a first selected head position having a 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) identifying the configuration of the head-disc assembly as depopulated when the first impedance is greater than the predetermined threshold.
A disc drive comprising:
- an array of rotatable discs;
- an actuator, adjacent the discs, operationally configured to support a maximum number of heads in a fully populated configuration and a reduced number of heads in a depopulated configuration, wherein each head is disposed at a unique head position of the actuator;
- and
- a servo circuit, operably coupled to the actuator, comprising a processor having associated programming to:
- (a) prior to spin-up of the discs, determine a first impedance of a write element at a first selected head position having a head when the disc drive is fully populated, but not when the disc drive is depopulated;
- (b) identify the configuration of the drive as fully populated when the first impedance is less than a predetermined threshold;
- (c) identify the configuration of the drive as depopulated when the first impedance is greater than the predetermined threshold;
- and
- (d) initialize the disc drive in relation to the identified configuration of the disc drive.
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 the configuration of the head-disc assembly, comprising steps of:
- (a) prior to spin-up of the discs, applying a current to a first write element at a first selected head position having a head when the head-disc assembly is fully populated, but not when the head-disc assembly is depopulated to sense the voltage across the selected head position;
- (b) determining a first impedance at the first selected head position;
- (c) identifying the configuration of the head-disc assembly as fully populated when the first impedance is less than a predetermined threshold;
- and
- (d) identifying the configuration of the head-disc assembly as depopulated when the first impedance is greater than the predetermined threshold.
A disc drive comprising:
- an array of heads adjacent a corresponding array of discs;
- and
- means for detecting a total number of heads in the array of heads by applying a current to a write element of a selected head while the heads are in contact with the disc prior to spin-up.
Dependencies are inferred from the claim text.