Abstract: An adaptive servo system for a disk drive compensates for a track being off center or distorted by analyzing the spectral content of the radial variation of the centerline of a track relative to a rotation axis, generating multiple component signals having frequencies that are harmonics of the rotation frequency, and combining the component signals in a positioning signal for an actuator. Analyzing the spectral content of the radial variation can be accomplished by a discrete Fourier transform of a position error signal while generating a correction signal that cancels all or part of previously determined components of the position error signal. The system converges to generating a periodic signal that compensates for multiple harmonics in the radial variation in the position of the track.

Abstract: The address of each track in a disk drive system is expressed in Gray code, and an appended bit of information is added to the Gray code, associated with the least significant bits thereof, the value of which is determined by the values of the most significant bits of the Gray code. The value of this appended bit is the same from Gray code to successive Gray code, as long as there are no changes in any significant bit between successive Gray codes, but the appended bit changes value when there is a change in a most significant bit between successive Gray codes.

Abstract: A disk drive apparatus includes actuator arms, each with a load beam mounted thereon, and a head mounted to a side of the load beam, with a lift rod mounted to that side of the load beam. An electrical conductor is connected to the head and extends along that side of the load beam. Each actuator arm defines a bore, and an annular member is included, having a first portion which is dimensioned to be an interference fit with a bore of the actuator arm, and a second portion adapted to cooperate with a portion of the actuator arm to hold a portion of the load beam therebetween with the first portion of the annular member positioned in the bore of the actuator arm. The disk drive apparatus includes a base and first and second covers on either side thereof, and a disk drive motor mounted to the base and extending from adjacent the first cover to adjacent the second cover. A voice coil actuator assembly extends from adjacent the first cover to adjacent the second cover.

Abstract: Disclosed is a rigid disk drive information storage device which includes a rigid disk having an outside diameter in the range of about 33-34 mm., with a housing having a footprint that includes a width of about 35 mm. and utilizing a rotary actuator for positioning read/write recording elements across the surface of the disk. The disk storage devices further includes a footprint with length of about 50.8 mm., and includes in one embodiment dynamic head loading apparatus for loading the read/write recording elements into operative relationship with the disk. In another embodiment the rigid disk drive utilizes contact start stop loading and unloading of the read/write recording elements. An inertial latch is also provided for preventing rotation of the actuator when the drive is subjected to a rotational force.

Abstract: A disk drive is disclosed including a substantially monolithic stator. The stator is formed by a metal injected molding (MIM) process in which high silicon iron is sintered to produce a stator made from loss magnetic material. The low loss magnetic material is a low hysteresis loss, high resistivity material. A substantially monolithic stator without multiple laminations is thus achieved. Avoiding stator laminations in this manner permits the fabrication of a disk drive having a significantly reduced vertical profile while still suppressing undesired eddy current and hysteresis losses in the stator. The stator is advantageously directly machined with a central bore to receive a bearing assembly for the spindle of the hub of the drive motor. The disclosed stator geometry is optimized in three dimensions to minimize stator volume and maximize the stator winding volume.