Abstract: The invention provides a wire-bonding apparatus for forming electrical connections between a semiconductor chip and a leadframe, comprising a plurality of bond-heads associated with a plurality of work holders on said wire bonding apparatus for holding a plurality of leadframes, wherein each bond-head of the apparatus is capable of independent bonding operation simultaneously with the other bond-heads, without synchronization of movement with the other bond-heads.

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: A space shift keying (SSK) modulation is disclosed. At the transmitter of a digital wireless communication with an antenna array, due to the fact that multipath fading will cause different responses for distinct array elements, different information signal bits (such as the “0” and “1” in binary shift keying) can be sent from different array elements to the receiver site. At the receiver site, the likelihood ratio test can be used to recognize the information signal bits transmitted from different array elements. The present signaling method for carrying information signal bits is a digital modulation method, which is known as space shift keying modulation.

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.

Abstract: Method and system aspects for controlling spindle motor speed during head loading in a disk drive are described. The aspects include inputting a time-varying reference velocity profile signal, and selecting a controller to control spindle motor speed. Further included is feeding forward control signals sufficient to precompensate for drag during a head loading event and maintain spindle motor speed within an operating tolerance.

Abstract: A method, apparatus, and article of manufacture for controlling a disk drive with multiple VCMs is disclosed. The apparatus comprises a first disk storage surface and a second disk storage surface. The first disk storage surface has a plurality of first data segments and a plurality of first servo track segments interspersed therebetween, and is readable and writeable by a first head controllable according to a first servo track signal read from at least one of the first servo track segments. The second disk storage surface has a plurality of second data segments and a plurality of second servo track segments interspersed therebetween, and is readable and writeable a second head separately controllable from the first head according to a second servo track signal read from at least one of the plurality of second servo track segments.

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.

Abstract: A variable pulse pulse width modulation digital-to-analog converter comprising: an input code register to store a digital input code to be converted; a PWM decoder, coupled to the input code register, to convert the input code to a series of pulses; an output driver circuit coupled to the PWM decoder, wherein the output driver circuit generates an output signal comprising pulses of a high logic level and pulses of an intermediate logic level; and a filter to integrate the pulses to generate an analog output value corresponding to the digital input code. In one embodiment, the output stage comprises an active tri-state driver, a multiplexer and at least two output reference voltage sources. Using a plurality of different amplitude pulse levels enables PWM DACs according to the present invention to provide greater resolution than conventional PWM DACs for a given clock frequency and conversion period.

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 of detecting and correcting reading errors of track identification (TID) of a magnetic data storage disk. The method comprises a means of constructing a encoded TID which is derived from generalized Gray code. The encoded TIDs have a distance of D between the adjacent code words, and a distance of at least 2D between non-adjacent code words within a band of M TIDS. The encoded TIDs can correct up to (D−1)/2 errors. The method also comprises means of encoding and decoding TIDS, and means of detecting and correcting errors with encoded TIDs.

Abstract: A direct access storage device (DASD) servo control system detects a servo pattern recorded in multiple cells of a servo sector and compares the cell-to-cell readback signal independently of the position error signal (PES). A servo sector of the disk contains multiple servo identification cells such that a servo readback signal is generated for each cell. If the servo signal data from two successive cells of a single sector, or from the same cell of successive sectors, differs by an amount greater than a predetermined error threshold, then a physical jarring or shock is indicated and the servo control system causes a write inhibit command to the write channel.

Abstract: A direct access storage device that (DASD) includes a sector servo control system that controls disk write operations by receiving a servo pattern readback signal in a sector, determining track centering for that sector, and generating a write inhibit signal before any write operations are initiated for that sector. The servo control system is able to make write inhibit decisions without software processing delays, enabling the system to produce a write inhibit signal quickly after an off-track excursion, and to terminate a write inhibit decision quickly after it is no longer needed.

Abstract: There is disclosed a disk for use in a disk drive and a method for making the disk. The position error signal (PES) fields for each track on the disk are written with predetermined data, e.g. servo data, encoded thereon. In the preferred embodiment: a) the data such as the track number is mapped into codewords of an error correction code (ECC); b) bit-vectors are used to encode the symbols for further redundancy; and c) the raw data written in the PES fields is constrained to equalize the analog signal characteristic used by the servo system for positioning. Thus, the invention allows the PES fields to be used as in the prior art while also being used as a source of digital data which is robustly recorded therein. In one aspect of the invention, the track ID's are written in the PES fields in a selected pattern in which the track ID for each track is recorded in two PES field groups.