Abstract: A method for writing a servopattern comprises writing a first burst at a first radial position, writing a second burst at a second radial position, wherein an edge of the first burst and an edge of the second burst have a substantially similar common radial position, and defining a portion of the edge of the first burst on a different revolution than defining a portion of the edge of the second burst.

Abstract: A disk drive manufacturing method calibrates the stitching gain of a position error signal (PES) by sampling servo information from a quadrature servo pattern while the head is maintained at the quarter-track positions and then calculating the kurtosis of the distribution of the PES values calculated from the samples. Because the kurtosis is a measure of the deviation from a normal or Gaussian distribution, the kurtosis of a PES distribution is used to optimize the stitching gain value through iteration until the kurtosis is close to zero, indicating that the PES with the optimal stitching gain values has a near-Gaussian distribution. The stitching gain calibration is performed for all heads and for multiple tracks across the surface of the disk for each head. The resulting values of stitching gain, each associated with a head and track, are stored in the disk drive memory and recalled during operation of the disk drive.

Abstract: Provided are a method, system, and program for initializing a storage device. A pulse response profile is determined for a storage system in response to a series of signals generated to seek to a location in the storage system. A determination is made of a desired response trajectory for the storage system that optimizes seek performance. An adjustment vector is calculated based on the pulse and step response profiles and the desired response trajectory to optimize the pulse response profile. The adjustment vector is stored in the storage device for use during storage device operations to apply to control signals generated to perform one seek operation.

Abstract: Provided are a method, system, and program for estimating coil resistance of a voice coil motor for an actuator assembly in a disk drive system. An estimation is made of a calibration coil resistance during a calibration operation. A determination is made of a distance moved during a seek operation. The determined distance and the calibration coil resistance are used to estimate a current coil resistance following the seek operation.

Abstract: The present invention involves a recordable disk having a first plurality of S1 servo sample wedges in a first servo zone at an outermost position on the disk, a second plurality of S2 servo sample wedges in a second servo zone which is radially adjacent the first servo zone, and a third plurality of S3 servo sample wedges in a third servo zone which is radially adjacent the second servo zone. The S1 servo sample wedges of the first plurality are equally spaced apart circumferentially around the disk by a first angle ?1, the S2 servo sample wedges of the second plurality are equally spaced apart circumferentially around the disk by a second angle ?2=?1*N1, and the S3 servo sample wedges of the third plurality are equally spaced apart circumferentially around the disk by a third angle ?3=?2*N2.

Abstract: A method for writing a servopattern comprises writing a first burst at a first radial position, writing a second burst at a second radial position, wherein an edge of the first burst and an edge of the second burst have a substantially similar common radial position, and defining a portion of the edge of the first burst on a different revolution than defining a portion of the edge of the second burst.

Abstract: Provided are a method, system, and program for initializing a storage device. A pulse response profile is determined for a storage system in response to a series of signals generated to seek to a location in the storage system. A determination is made of a desired response trajectory for the storage system that optimizes seek performance. An adjustment vector is calculated based on the pulse and step response profiles and the desired response trajectory to optimize the pulse response profile. The adjustment vector is stored in the storage device for use during storage device operations to apply to control signals generated to perform one seek operation.

Abstract: Provided are a method, system, and program for estimating coil resistance of a voice coil motor for an actuator assembly in a disk drive system. An estimation is made of a calibration coil resistance during a calibration operation. A determination is made of a distance moved during a seek operation. The determined distance and the calibration coil resistance are used to estimate a current coil resistance following the seek operation.

Abstract: The present invention involves a recordable disk having a first plurality of S1 servo sample wedges in a first servo zone at an outermost position on the disk, a second plurality of S2 servo sample wedges in a second servo zone which is radially adjacent the first servo zone, and a third plurality of S3 servo sample wedges in a third servo zone which is radially adjacent the second servo zone. The S1 servo sample wedges of the first plurality are equally spaced apart circumferentially around the disk by a first angle &thgr;1, the S2 servo sample wedges of the second plurality are equally spaced apart circumferentially around the disk by a second angle &thgr;2=&thgr;1*N1, and the S3 servo sample wedges of the third plurality are equally spaced apart circumferentially around the disk by a third angle &thgr;3=&thgr;2*N2.

Abstract: A system and method for adaptively compensating for real-time variations in mechanical dynamics of a head-positioning assembly during track follow and seek operations. The head-positioning assembly includes a voice coil actuator that positions a read/write head utilizing a coil and carriage in conformity with an actuator control signal. Variations in resonant mode characteristics are anticipated in real-time in accordance with measured temperature variations. These parametric variations are translated in real-time by a state space model to determine a secondary velocity and displacement of the read/write head during track follow and seek operations. In response to this secondary velocity and displacement determination, the actuator control signal is dynamically adjusted to compensate for the determined secondary head velocity and displacement, thereby improving head positioning accuracy and increasing servo bandwidth.

Abstract: A system and method for precompensating for tangential misalignment in a direct access storage device adjusts a SID timing window individually for every track or surface of the direct access storage device. The system and method generate a calculation of the tangential misalignment and adjust, in accordance with the calculation of tangential misalignment, a timing window during which the transducer head reads the information located on the storage surface. The calculation of tangential misalignment may be the result of a direct measurement of the tangential misalignment, or may be converted from radial misalignment data. The adjustment of the timing window may comprise opening the timing window an amount depending upon the degree of misalignment of each track, and may comprise shifting the window in time either forward or backward depending upon the nature of the calculated misalignment.

Abstract: A hard disk drive for a computer system has at least two actuators for reading data from or writing data to the disks. The actuators may be configured to support the different methods of data access required of them. For example, if large quantities of sequential data are performed, one operation uses both actuators to increase throughput. However, if mostly random operations are to be performed, then independent usage of the actuators is preferred. These two methods of usage can be supported simultaneously, and can even be dictated by the user. The tracking format of the actuators can be configured such that the next logical track is physically located under a head on a different actuator to improve sequential operation. The actuators also may be utilized in a dual-channel configuration so that data can be written to both actuators at the same time, or read back at the same time to improve throughput. In addition, either of these configurations can be selected on a transfer-by-transfer basis by the user.

Abstract: In summary, preferred embodiments disclose a system, method, and program for determining a value for non-mechanical noise within a disk drive system. The non-mechanical noise is likely related to instability in a head which reads data from a magnetic surface within the disk drive system. First, a sample of position error signals (PES) indicating non-repeatable runouts (NRRO) is provided from read operations within the disk drive system. Spectral analysis is then performed on the provided samples to calculate non-filtered power values for the NRRO values at different frequencies. A filtered power spectrum is determined within a frequency range excluding mechanical noise. A filtered power value is calculated from the determined filtered power spectrum within the frequency range excluding mechanical noise.

Abstract: A method and apparatus for providing feedforward control of two interacting actuators to compensate for interaction there between is disclosed. State models for each actuator that processes acceleration for each actuator provide an estimate of head acceleration for each of the actuators and to provide feedforward control signals to the actuators for controlling the positioning of the heads based upon the estimates of head acceleration for each of the actuators.

Abstract: A method and system in accordance with the present invention for minimizing the loss of data by a write head is disclosed. The method comprises providing a desired write head width based upon a hard error rate. The method further comprises adjusting at least one parameter of the servo control logic based upon a comparison of the width of the write head and the desired write head width, wherein the write head will not exceed the hard error rate when writing data. Through the use of a system and method in accordance with the present invention a servo system can be designed based on a constant hard error rate. The write inhibit window and the settle delay for writing operations in a servo system will be optimized, based on the hard error rate, for each individual head in the disk drive configuration. This will increase the speed of the servo process without affecting the reliability of the data.

Abstract: There is disclosed an error correction and detection method and apparatus for retreiving predetermined data, e.g. servo data, from the position error signal (PES) fields of a disk in a data storage system . In the preferred embodiment the PES data such as the track number is mapped into codewords of an error correction code (ECC) which are then further divided into a set of symbols which are mapped onto a second set of bit vectors which have a constant weight. The preferred encoding method is selected to equalize the analog signal characteristics of the PES fields so that minimal, if any, change in the conventional servo detection circuitry needed to use the PES fields of the invention both as analog and digital information.

Abstract: A method and apparatus for reducing track misregistration due to digital-to-analog converter quantization noise. In hard disk drive (HDD) servo control systems, quantization noises (or roundoff errors) due to the finite precision of the D/A converter (DAC) driving the VCM contribute a significant portion of the total track-misregistration (TMR). The present invention provides a quantization error feedback (QEF) technique to reduce TMR due to DAC quantization noises. The QEF technique according to the present invention offers a simple method of reshaping the spectrum of this noise to minimize its contribution to TMR. In the digital signal processor (DSP) implementation of the QEF schemes, the quantization error is monitored and accumulated in the DSP; when sufficient error has accumulated, the MSB feeding the DAC are modified such as to cancel the effect of the error.

Abstract: A method, apparatus, and article of manufacture for rotational position reordering of queued commands in a data storage device based on settle time estimator feedback. An initial settle time estimation is programmed into a servo controller for the data storage device. As data operations are performed in the data storage device, an actual settle time is measured for the data operations, generally through the use of a timer in the servo controller. The settle time estimation is then modified based on the actual settle time and the data operations are reordered or scheduled based on the settle time estimation. Specifically, the settle time estimation is adjusted based on a success rate for the data operations, wherein the success rate comprises a comparison of the actual settle time versus the settle time estimation.

Abstract: Linearity compensation is provided for a position error signal based on repeatable and non-repeatable run out in a data storage device. The run out is measured on a track of the data storage device at a plurality of points, such as a track center and one or more points offset from the track center. The run out is typically measured using either an unstitched primary position error signal or an unstitched quadrature position error signal. The offsets are usually stitch points for the position error signal. A component of the run out is extracted at the points, wherein the component generally comprises one or more characteristics of the run out, such as a frequency, a set of frequencies, a root mean square, or some other characteristic of the run out. The linearizing equation to be used for the position error signal is identified based on the measured run out and generally comprises a polynomial function.

Abstract: A system, method, and article of manufacture for adaptive re-mapping of head addresses in a data storage device. A logical address received by the data storage device is converted into a corresponding physical address, such as cylinder or track, read/write head, and sector. The selection of the read/write head is then re-mapped by the data storage device to a more optimal selection. Thereafter, the desired operation can be performed using the physical address including the re-mapped selection of the read/write heads.