Abstract: A process for measuring the thickness of an insulating material. The process includes providing a device used to measure capacitance, and electrically connecting the capacitance measuring device to a heat sink and an electrical, heat-generating component. The thickness of the insulating material is determined by measuring the capacitance of the insulating material according to the formula; B=?r?0A/C, where B is the thickness of the insulating material, C is the capacitance, A is the area of the heat generating component, ?0 is the permittivity of free space and ?r is the relative dielectric constant of the insulating material.

Abstract: Improvements in placement of timing patterns in self-servowriting include correcting for systematic errors due to geometric effects. A correction is made for varying systematic errors, such as when the recording head has spatially separate read and write elements. Further, servopattern rotation due to residual or unmeasured systematic errors is reduced by using a once per revolution clock index derived from the motor drive current waveform or any other sensor. In one aspect of correcting for systematic errors in the writing of timing patterns on a storage medium of a storage device, a time interval between a trigger pattern written at a first radial position of the storage medium and a rotational index is measured. The rotational index is related to the rotational orientation of the storage medium with respect to a fixed frame of the storage device.

Abstract: A method for writing timing marks on a rotatable storage medium, such as on a disk in a disk drive, includes the steps of: 1) during a rotation of the disk, detecting the passage of at least a portion of a first timing mark located at a first radius of the disk, and 2) writing a second timing mark at a second radius of the disk, the location of the second timing mark being based at least in part on a stored calculation of a delay from the time of passage of the first timing mark during a rotation of the rotatable storage medium. The location of the second timing mark is calculated based on alternative time intervals between detected timing marks and on various functions of the time intervals.

Abstract: During self-servowriting, burst information is written within slots defined on tracks of a recording medium. In writing the burst information, write to read interference, caused by large offsets in separate read and write elements of a recording transducer, is to be avoided. In order to avoid the write to read interference, the slots are carefully chosen. The choice of a particular slot can be independent of any predefined order, such as a successive order. Further, the order in which slots are chosen may be altered during the propagation process.

Abstract: A method is provided for writing a servo-pattern on a storage medium. According to the method, first timing marks are written at a first radial position of the storage medium, and the head is moved to a second radial position. Time intervals between selected pairs of the first timing marks are measured, and other timing marks are written at the second radial position of the storage medium. The measuring step is performed after the moving step. In one preferred method, the steps of moving, measuring, and writing other timing marks are repeated until the servo-pattern is written on an entire surface of the storage medium. A method is also provided for generating an initial aligned pattern of timing marks for self-servo-writing on a storage medium.

Abstract: A method for writing tracks on a rotating disk media data storage device comprising the steps of: receiving a set of component parameters; and adjusting track pitch for each of the tracks to be written in each disk according to the component parameters. According to another embodiment a disk drive includes at least one disk comprising a two or more of tracks in which the track pitch between each pair of adjacent tracks is set based on component parameters such as the recording head widths. According to another embodiment a servowriter is adapted to perform the method discussed above.

Abstract: During self-servowriting, burst information is written within slots defined on tracks of a recording medium. In writing the burst information, write to read interference, caused by large offsets in separate read and write elements of a recording transducer, is to be avoided. In order to avoid the write to read interference, the slots are carefully chosen. The choice of a particular slot can be independent of any predefined order, such as a successive order. Further, the order in which slots are chosen may be altered during the propagation process.

Abstract: A method for writing timing marks on a rotatable storage medium, such as on a disk in a disk drive, includes the steps of: 1) during a rotation of the disk, detecting the passage of at least a portion of a first timing mark located at a first radius of the disk, and 2) writing a second timing mark at a second radius of the disk, the location of the second timing mark being based at least in part on a stored calculation of a delay from the time of passage of the first timing mark during a rotation of the rotatable storage medium. The location of the second timing mark is calculated based on alternative time intervals between detected timing marks and on various functions of the time intervals.

Abstract: Methods and systems for self-servowriting a data storage medium are disclosed, including servoing to propagation bursts of a propagation pattern located in tracks other than an immediately preceding track. Reference levels used to position a recording head are accordingly kept in a usable dynamic range necessary to keep servo track spacing constant across the medium. The methods and systems are disclosed in connection with a rotary actuator having spaced read and write heads. Similar methods are disclosed for writing trigger or timing bursts of the propagation pattern.

Abstract: A method of locating in a non-destructive and non-invasive manner power plane-to-power plane shorts or I/O net-to-power plane shorts found in a printed circuit board or a multi-chip-module by way of a magnetic field generating probe is described. Thousands of nets can be simultaneously tested to detect not only the presence of a short but also to accurately pinpoint its position. For high resistance shorts, the probe is provided with a pot core housed inductor located at its tip, and is used at low frequencies to minimize the effect of the capacitive impedance between the power planes. For low resistance shorts, the probe is used at high frequencies, delivering equal but opposite current to each of two matched inductors at the tip of the probe to maximize mutual inductive coupling while minimizing electrostatic capacitive coupling with the board or module. In both cases, the highest current stress is on the probe rather than on the expensive and fragile package under inspection.

Abstract: An apparatus and corresponding method for detecting, locating, or defining a short in a thin-film module. The apparatus includes a mechanical fixture supporting the module. A current source provides a current pulse to the module which produces a magnetic field and heating nearby the short which turns on and off as the pulsed current in the short turns on and off. Polarized light is directed onto the module, with an intermediate element disposed between the module and the source of the polarized light. The intermediate element may be a stress birefringent coating (e.g., a polyimide insulating layer) disposed on the module and onto which the polarized light is directed. The sample is rotated 0 to 45 degrees to maximize the birefringent effect. Alternatively, the intermediate element may be a magneto-optical Faraday rotator.

Abstract: A method and apparatus for locating shorts in multi-layer electronic packages during manufacture allows repair of the shorts and improved yields of the packages. A multi-layer package is fitted in a fixture after forming a thin film layer of metalization, and test is performed to detect shorts in the package. If a short is detected, a low current, high frequency signal is injected in pins on a bottom surface of the package. An approximate two dimensional location of the short is sensed by detecting an electromagnetic force induced by a magnetic field inductively coupled to a sensor proximate to the short on a top surface of the multi-layer package. The approximate location of the short is then inspected to precisely locate the short.

Abstract: A technique for writing a servo-pattern on a storage medium located in a recording device having an internal recording head. A timing pattern is generated on the storage medium with the internal recording head and a radial positioning value is determined in order to radially position the internal recording head. The servo-pattern is written using the internal recording head at locations determined by the timing pattern and the radial positioning value.

Abstract: During a write revolution of a storage medium, a transition is written on the storage medium while servoing on another transition previously recorded on the storage medium. During that write revolution, a position error signal corresponding to the position error of the transducer relative to the previously recorded transition is determined. That position error signal is then stored, during the write revolution, to be used in computing a reference track value associated with the transition being written to correct for the position error. Additionally, a product servo-pattern is written, which includes an embodying of the position error therein.

Abstract: A technique for writing a servo-pattern on a storage medium located in a recording device having an internal recording head. A timing pattern is generated on the storage medium with the internal recording head and a radial positioning value is determined in order to radially position the internal recording head. The servo-pattern is written using the internal recording head at locations determined by the timing pattern and the radial positioning value.

Abstract: A technique for writing a servo-pattern on a storage medium located in a recording device having an internal recording head. A timing pattern is generated on the storage medium with the internal recording head and a radial positioning value is determined in order to radially position the internal recording head. The servo-pattern is written using the internal recording head at locations determined by the timing pattern and the radial positioning value.

Abstract: A device which detects conductors, the device has a portion which applies a current to a conductor consisting of a first frequency signal and a second frequency signal. The frequency of the second frequency signal is double the frequency of the first frequency signal. The device has another portion which detects a DC voltage across the conductor. An adjusting portion adjusts a phase of the first frequency signal relative to a phase of the second frequency signal to produce a zero detected DC voltage across a representative length of conductor known to be free of defects.

Abstract: Position sensors for detecting the position of a linear motor relative to a platen are disclosed. In one embodiment, the sensor includes first and second magnetic members having teeth disposed relative to the teeth on the platen. A single turn planar drive winding is disposed around at least one of the teeth of the first and second magnetic members for producing a first and a second drive flux within each of the magnetic members. A single turn planar sense winding is disposed around at least one of the teeth of the first and second magnetic members for generating first and second outputs which are a periodic function of the position of the sensor relative to the platen. In another embodiment of the present invention, the sensor includes two magnetic members each having four pole pieces. A drive winding is disposed on each member for establishing first and second fluxes in each member which are symmetrical about a center of each member.

Abstract: A method and structure permit the precision alignment in the packaging of optical components, such as lasers, detectors, lenses and waveguides. The technique involves capacitance measurements of an array of plates placed on the optoelectronic device chip and its package substrate. The technique uses phase sensitive detection to sense the total current capacitively coupled into a passive plate on the device chip from two overlapping plates located on the package substrate. When the device chip is properly aligned with respect to the package substrate, the summed current sensed with a third overlapping plate on the package substrate is a null.

Abstract: A method and apparatus for measuring dynamic head and track misregistration in, for example, a magnetic disk file. A reference signal waveform is recorded onto a track on a recording medium. The track has a center line and an off-center line parallel to the center line. The recorded reference signal waveform is read a plurality of times with the transducer centered approximately above the off-center line of the track to produce a plurality of off-track playback signal waveforms. A track misregistration signal waveform is produced by computing the difference between one off-track playback signal waveform and the average off-track playback signal waveform.