Abstract: A digital peak detection system digitizes analog signals and provides absolute values to a series of one cycle delays, and to a sequence of comparator stages. Each digital sample is parallel compared to a number of preceding samples equal to the number of active comparator stages. Control signals activate comparator stages to determine sample comparison window length, including lengths exceeding the number of samples between recorded peaks. Peak detection is optimized using a variable gain amplifier whose gain is updated based upon amplitude difference between actual and desired peak samples. When sample amplitudes are smaller than a qualifier threshold, a countdown timer increases amplifier gain after lapse of a programmed time without detecting a qualified pulse. Gain is also updated when the analog to digital converter saturates. Initial gain values can be programmed, and gain stored at the end of a servo mode for future use in reducing gain control loop convergence time.

Abstract: The invention uses piezoelectric sensors to test disk drives. Both contact start-stop and load-unload type disk drives may be tested. A piezoelectric sensor is affixed to a disk drive to test for disk drive mechanical integrity. One method of affixing the sensor to the disk drive is using a mechanical clamp. The clamp is intended for repeated use on many disk drives, and therefore its easy removal is important. An alternative clamping apparatus is a magnetic clamp. In use, the clamp affixes the piezoelectric sensor to a disk drive in an optimal location with optimal force. Affixed piezoelectric sensors are used to detect aberrant behavior generated by non-optimal disk drive performance. The clamp/sensor combination detects acoustic signal in a disk drive which is used to determine whether or not a disk drive has adequate head-disk clearance. The apparatus is flexible, allowing testing after assembly of head-disk assembly and before or after servowriting and final disk drive assembly.

Abstract: A disk drive in which a movable latch locks the data transducer assembly to prevent movement due to shock. The movable latch cooperates with an actuator by engaging an actuator extension arm. The movable latch also engages a stationary magnet with one of two latching magnets. The movable latch arm is mounted to a shaft which extends into a sealed casing which incorporates a plunger. The plunger is located in a chamber filled with viscous fluid which is not subject to migration or outgassing from the chamber. The viscous fluid provides resistance to sudden movements of the plunger. Latch release is achieved by application of low continuous force to the actuator arm by a voice coil motor.

Abstract: A cold trap assembly having Peltier Junction assembly is provided to reduce the head stiction between a disc drive head and a disc. The Peltier Junction assembly includes a cold region which has a temperature lower than the ambient temperature of the disc drive. Vapors from outgassing components in the disc drive condense on the cold region, thereby reducing the amount of vapors which may condense on the disc surface.

Abstract: The invention provides for encoding position information for zone number, subtrack number and sector number, with less number of bits. The invention also provides for redundant position information to accurately determine the position of the transducer head.

Abstract: In a disc drive, a position error signal (PES) can be generated that is insensitive to the read element's magnetic and physical geometry and micro-track profile, and that has a spatial domain periodic frequency that corresponds to a frequency region of the micro-track profile that facilitates a high magnitude response. The servo pattern for generating this PES includes a first servo burst pair (A,B) and a second servo burst pair (C,D) of servo burst members, each pair written as normal and quadrature channels.

Abstract: A method for adaptively controlling the write inhibit signal in a disk drive apparatus. The disk drive apparatus include magnetic disks manipulated such that the total space that is to be allocated for storing data has been measured and recorded such that the tracks for storing data have been servo written at a wider spacing than a nominal track spacing. The drive's operational circuitry includes access to modified write inhibit threshold data that is based on the drive's nominal design track misregistration allowance, plus any track width increase gained by adaptively controlling the track pitch. The modified write inhibit threshold essentially facilitates an acceptable delay in activating a write inhibit signal. The data tracks on each of the magnetic disks have been servo written utilizing the wider track spacing while maintaining the track misregistration allowance that corresponds to the nominal track spacing.

Abstract: An improved attachment of an actuator E-block of an actuator assembly to a pivot bearing assembly for a disc drive, the E-block having a central bore having a pair of alignment edges to pressingly engage a cartridge bearing of the pivot shaft bearing assembly, and the cartridge bearing supporting a canted coil spring within a peripheral groove so that the spring is interposed between the cartridge bearing and the E-block within the E-block bore. One or more fasteners extend through the wall of the E-block adjacent the alignment edges to pressingly engage the cartridge bearing against the alignment edges, the canted coil spring filling the clearance gap between the cartridge bearing and the E-block bore to provide a resilient support to the E-block.

Abstract: A method and apparatus for detecting and measuring head-disc interference, in a disc drive, for the purpose of taking preventative and corrective measures, to prevent disastrous head crashes and permanent data loss, is disclosed. The method and apparatus detect and measure the frequency modulation (FM) of a read back signal generated by longitudinal head oscillation, as a result of head-disc interference. The longitudinal head oscillation can be ascribed to the non-linear response of the air bearing supporting the head on the disk surface. The response exhibits a vibration frequency in the head in the 100 to 250 kHz range. The more severe the interference contact is, the higher the vibration amplitude which then leads to read signal frequency modulation (FM). A method and apparatus is described to detect the FM modulation and thereby to detect the severity of the head disk interference for proximity recording. A pre-written pattern on the disk can be read back to monitor for FM, and a modulation index, .beta.

Abstract: An electrical circuit package including disk drive operation and control circuitry is formed in multiple layers, including a compliant circuitry layer coextensive with the package, and additional conductive and dielectric layers to form relatively stiff circuit panels bonded to the compliant layer and spaced apart from one another. Portions of the compliant layer, between confronting edges of adjacent circuit panels, provide compliant joinder segments. Each joinder segment electrically couples its associated pair of circuit panels, and structurally couples the panels in a manner that permits a selective, non-coplanar orientation of the panels relative to each other. Thus, the panels are electrically and structurally coupled in a manner that facilitates testing the circuit package as a single unit, followed by installation of the package to a disk drive housing with the circuit panels integral with the housing and in the desired non-coplanar arrangement.

Abstract: A parking device for an actuator in a storage device which includes a voice coil motor having a magnet, providing a magnetic field including a magnetic flux, and a coil coupled to the actuator. The parking device includes a magnetically permeable capture structure forming a path for the magnetic flux and generating a capture region, the capture region being a region of magnetic flux adjacent to the capture structure; and a capture member, having a face plate, coupled to the actuator such that the capture member enters the capture region to park the actuator when the actuator is in a park position. In a further aspect, the parking device includes a magnet structure supporting the magnet, having a top plate and a bottom plate, wherein the capture structure is positioned between the top and bottom plates and forms a magnetic circuit path for the magnetic flux with the magnet, and the top and bottom plates.

Abstract: A data recording disk file includes rotatable disks with concentric data tracks thereon. The data disk file includes servo information recorded on at least one of the disks, at least one head for reading the servo information during rotation of the disk, and a voice coil motor (VCM) attached to the head for positioning the head relative to the data tracks. A servo is driven by signals read from the head to control the VCM. The servo includes a processor employing an estimator model for estimating the parameters of the VCM and for generating, from the estimated parameters and the servo information, a digital control signal. The digital control signal is converted to an analog control signal. The control signal is applied to a power amplifier which generates an input current for use by the VCM. The processor provides solely a single estimator model which operates in both saturated mode and linear mode depending on the magnitude of the digital PES.

Abstract: A data recording disk file includes rotatable disks with concentric data tracks thereon. The data disk file includes servo information recorded on at least one of the disks, at least one head for reading the servo information during rotation of the disk, and a voice coil motor (VCM) attached to the head for positioning the head relative to the data tracks. A servo is driven by signals read from the head to control the VCM. The servo includes a processor employing an estimator model for estimating the parameters of the VCM and for generating, from the estimated parameters and the servo information, a digital control signal. The digital control signal is converted to an analog control signal. The control signal is applied to a power amplifier which generates an input current for use by the VCM. The processor provides solely a single estimator model which operates in both saturated mode and linear mode depending on the magnitude of the digital PES.

Abstract: A magnetic head position detecting method is provided in which a first and a second position detection signal representative of a particular position of a magnetic head with respect to a magnetic disk is obtained. The first and the second position detection signal preferably is obtained by utilizing a burst pattern formed on the magnetic disk. Subsequently, a third position detection signal is generated by multiplying the first and the second position detection signals by a predetermined gain so that the third position detection signal changes linearly. The particular position of the magnetic head is detected by using the third position detection signal. In addition, a magnetic disk apparatus implementing the magnetic head position detecting method is provided.

Abstract: A mechanism for compensating the servo data in a disk storage drive is provided. On each recording surface of a disk, a plurality of servo regions are diametrally formed in data regions along the diametral direction of the disk. In the servo region, a gray code (cyclic binary code) representing the address of a data track is recorded so as to correspond to the data track, and a burst pattern as a signal for positioning the head on the track are recorded. In the data track region, tracks are formed at a predetermined pitch P and in the tracks, a plurality of data is recorded. ID (Identification) is the identification information of the individual data. A servo compensation signal region is formed at a position sandwiched by the data region and the servo region known as the write recovery area. This is to compensate the servo signal in the servo region, thereby to enable error recovery when a read error or the like occurs in the servo region.

Abstract: A load beam for a data storage device having a first end operatively configured for connecting to a head actuator arm and a second end operatively configured for supporting a signal transducer head is provided. The load beam has a flange with a bent portion. The bent portion is arranged by bending the standing portion of the flange in the middle thereof outwardly from the load beam. The bent portion is arranged so that it progressively becomes wider as it runs toward the end of the load beam. The flange is adapted to be nearly flush with a flat base surface at the end of the load beam so as not to have a standing portion and such that signal wires may be connected to a signal transducer head without being unduly bent.

Abstract: A magnetic fluid seal is provided by mounting an annular, axially polarized magnet mounted on the device base member and an annular ring pole piece with an inner diameter that cooperates with an outer diameter surface of the hub assembly to form a fluid gap that is radially outward and within the axial extent of the spindle bearings. The secondary gap of the seal assembly is within the bearing assembly sealed volume while the principal sealing gap is within the hub assembly to confine any debris or aerosols resulting from high rotational velocity or shock to be contained in proximity to the flux fields that can recapture any magnetic material. The assembly also inherently presents an effective conductive path to provide enhanced grounding of the rotating assembly through the magnetic fluid in the second gap which is not subject to impairment caused by bonding materials.

Abstract: An array of memory cells is physically divided into a data area and a tag area so that respective parts of the two areas share a word line but can be separately erased en bloc. The data area and tag area sharing one word line constitute a single logical unit. In the logical unit, the tag area stores location information for defective memory cells in the corresponding data area. On the basis of this information, the system avoids the use of the defective memory cells. The defective memory cell information is programmed in a test step performed after chip manufacture and, at the same time, ECCs are generated for the defective memory cell information and written to the tag area. Furthermore, the system is informed of the invalidity of the data area that shares a word line with a tag area by writing predetermined data to the tag area. Even when the data area is erased en bloc, the tag area is not erased and the defective memory cell information is retained there.

Abstract: A disk drive slider is designed to make contact, if any, in a region of the slider which does not have a substantial effect on the fly height. Preferably, the slider utilizes a tapered center rail having a narrow tail which is closest to the disk and a pair of outside rails which are wider at the leading edge. The center rail tapers from a narrow leading edge to a wider support region and then tapers to a narrow trailing edge. The trailing edge is closest to the disk and provides virtually no contribution to aerodynamic support of the slider. Since the trailing edge does not contribute to the support of the slider, any contact induced wear can be tolerated without affecting the fly height. Even further, the wear characteristic is self-limiting. That is, after the initial wear has taken place, the likelihood of further wear is reduced.