Abstract: A system for hardware intelligent speed monitoring and auto-retract is disclosed. The system contains a monitoring device that monitors the TACH (Tachometer) output of motor driver. The device provides a trigger to the signal processor and a retract mechanism to retract the actuator when the spindle motor speed is unexpectedly much higher or lower than normal speed. The system DSP (Digital Signal Processor) is unaware of such occurrence.

Abstract: According to one embodiment of the present invention, a disc drive includes a disc and a transducer supported by an actuator assembly that is accelerated by controlling current in a voice coil. The disc drive controls a position of the transducer over a present track on the disc in a track-and-follow mode, generates an estimated bias current to be applied to the voice coil to balance a bias on the actuator assembly when the transducer is over the present track, starts a movement of the transducer toward a target track in a seek mode, enters the estimated bias current into a bias table if an immediately preceding movement of the transducer in the seek mode was longer than a seek length boundary such that nonlinear friction in a pivot in the actuator assembly is less substantial, and applies a bias current to the voice coil calculated based on a bias current entry in the bias table during the seek mode.

Abstract: A method, disc drive, and data handling system for optimizing the data writing/transmitting process are disclosed. The disc drive implemented method involves detecting at a current burst whether data written to a previous wedge is recoverable and making the disc drive's buffer space holding that data available for holding other data when the written data is recoverable. The disc drive implemented method also involves detecting at the current burst whether data to be written to a following wedge will encroach upon data written in adjacent tracks and allowing the data to be written in the following wedge when the encroachment is not too severe.

Abstract: An error correction and miscorrection detection apparatus includes a memory buffer for storing user data contained in a data signal. A syndrome computer circuit generates a plurality of EDC syndromes form an EDC codeword. The EDC codeword includes user data encoded with a plurality of m-bit EDC parity symbols. The EDC codeword is encoded with plurality of n-bit ECC parity symbols to form the data signal, such that m>n. An ECC error correction circuit corrects the user data with an error signal generated for each corruption of the data signal. A completion is signal generated once correction of the EDC codeword is complete. A syndrome fix-up circuit is configured to adjust the EDC syndromes based on the received error signals. Once the completion signal is received, a miscorrection by the ECC error correction circuit is detected if a value of the adjusted syndromes is not equal to zero.

Abstract: A disc drive is provided which incorporates a rotatable actuator which is mounted to a base of the disc drive through a pivot mechanism. The actuator positioning is controlled by a servo system and during track following operations, the actuator arm is caused to move. In one embodiment, the servo tracks incorporated in the disc drive are distorted when written in by the injection of a sinusoidal signal. In another form, the disc containing the servo information is caused to rotate about an axis which is offset from the disc axis. A method of creating a servo track is also disclosed.

Abstract: A disc drive system and method of screening an actuator resonance includes a servo controller providing a multi-servo zone architecture. The servo controller partitions the disc into a plurality of servo zones. Each of the servo zones has a corresponding servo gain. When an actuator resonance is detected in one of the servo zones, the servo controller reduces the corresponding servo gain of the detected servo zone such that a drive with very low resonance at a certain zone does not affect the servo bandwidth of the other good zones. Accordingly, a drive with very low resonance is prevented from being scrapped. Further, the screening technique allows a drive to have an adequate servo margin for its normal operation after going through a resonance detection test.

Abstract: A method of storing values that involves splitting each value into a n-bit value and an overflow value, and storing, in a main table, the n-bit values in order of increasing magnitude of the values. For each overflow value, the position of the smallest n-bit value is stored in an overflow table. To retrieve a value, the position of the corresponding n-bit value is compared to the positions stored in the overflow value to determine the overflow value of the n-bit value. The actual value is then obtained from the n-bit value and its overflow value.

Abstract: An RF signal filter includes an elongate block of dielectric material having a transmit electrode, an antenna electrode and an array of spaced resonators extending between the transmit electrode to the antenna electrode. A signal trap resonator is positioned adjacent to the transmit electrode but opposite the array of spaced resonators. The filter also includes a isolated electrode positioned between but spaced apart from the trap resonator and a local ground conductive layer. A PIN diode switch is operably connected between the isolated electrode and the local ground conductive layer for shifting of the resonant frequency of the trap resonator.

Abstract: A preferred system for measuring bearing friction first measures voice coil motor current values required to move an actuator arm assembly to each of several cylinder position intervals. Torque values required to move the actuator arm assembly are then computed using the measured voice coil motor currents. Drive-level bearing friction values are then calculated using the computed torque values and then combined into a composite indicator.

Abstract: The present invention is a preferred monoblock ceramic bandpass duplexer filter. The preferred filter has at least three I/O pads. One of the pads is coupled to an antenna, another is connected to a transmission circuit and the last pad is connected to a receive circuit. The filter is comprised of two sections: a transmission section and a receive section. The transmission and receive sections include resonators disposed on respective sides of the antenna pad. A first alternative signal path is disposed adjacent the ends of the transmission resonators. A second alternative signal path is disposed adjacent to the ends of the receive resonators. Each alternative signal path couples adjacent and non-adjacent resonators. A further feature of the filter of the present invention includes a shunt zero resonator for the transmission section. To the contrary, the present invention allows the elimination of a shunt zero resonator for the receive section of the filter.

Abstract: A disc drive typically contains at least one disc which is divided into sectors. The method of eliminating reassignments involves copying data stored at one sector (referred to as a moving sector) to another sector (referred to as a moving spare), and assigning the logical address associated with the moving sector to the moving spare. The elimination process is repeated until the reassignments are eliminated. Verification of the data copied is conducted to ensure data integrity. Furthermore, the elimination process is preferably executed only when the disc drive is in an idle mode. Records are kept and updated as the process is carried out so that the process can be continued even if interrupted.

Abstract: Piezoelectric elements or similar microactuators perform fine positioning in a system including at least two masses bendably coupled to a larger body. A servo controller receives a position signal from a sensor on the first mass, from which it generates a signal to control microactuators coupling other masses to the body. The movement of the other masses thereby exerts a controlled reactive force upon the body and upon the first mass. Examples include disc drive systems in which the reactive forces are used to counteract one or more unwanted excitations in an actuator body or actuator arm.

Abstract: An information handling system, such as a disc drive, includes a base, a disc stack rotatably attached to the base, and an actuator assembly movably attached to the base. Attached to one end of the actuator assembly is one or more transducers. The disc includes data areas and servo areas written at angular locations on the disc. The disc drive also has a disc drive controller which includes a motor speed controller, a write gate controller, and a device for predicting the disc speed at an upcoming servo and disabling the write gate if the predicted disc speed is outside a selected range of disc speeds. The device for predicting the disc speed may further include an abort signal generator that produces an inhibit write gate signal in response to the predicted disc speed being outside the selected range of disc speeds.

Abstract: A disk drive system is described for forming and reading precise optically detectable patterns on rotating members of a disk and spindle assembly used in data storage system. In particular the invention describes a magnetic disk drive employing a laser system to form and sense optical clock patterns placed on the rotating members of the disk drive. These optically detectable patterns are used to create an accurate clock track. The clock may be used to create multiple accurate magnetic patterns on one or more disks attached to a disk and spindle assembly in a magnetic data storage system. By successively changing the radius at which the magnetic patterns are created it is then possible to create multiple magnetic patterns at successive radii with all such magnetic patterns having a precise geometric relationship to each other. Alternatively, the accurate clock pattern may stand alone as an encoder.

Abstract: A method and apparatus for providing a constant output power supply that is different from a system power supply. A system power supply voltage is sensed and compared to a predetermined output voltage value. If the supply voltage is greater than the voltage value, the supply voltage is decreased, such as through regulation. If the supply voltage is less than the votlage value, the supply voltage is increased, such as through charge pumping. The apparatus is preferably coupled between a system power supply and a circuit that operates on a voltage that is different from the supply voltage.

Abstract: In a SCSI controller, unexpected messages are automatically received in response to an attention signal by receiving all of the bytes constituting the message and storing those bytes in an available register file selected from a plurality of register files in the controller. Once the entire message has been received and stored, a determination of an appropriate response is initiated. The register files are also used to hold selection information during a bus-initiated selection, so additional architecture is not required.

Abstract: Generally, a method checks the error signals of the interleaves to determine if the number of error bursts, burst error lengths or burst size is exceeded. These values are predetermined limits. To this end, the present invention tracks the number of errors and attempts to "fit" the errors in the programmed parameters of the burst size and burst limit values, such as illustrated above. If there is no fit, then an error signal is provided by burst limit checker.

Abstract: An entity relationship diagram for a relational database is generated from introspection of the relational database to determine which entities should be included within a specific table to be displayed. Tables within the entity relationship diagram are displayed with icons hyperlinked to other portions or displays of the entity relationship diagram. A trigger icon links the displayed table to a display of the trigger information for the displayed table. A primary key icon indicates which column of the displayed table is utilized as the primary key for the displayed table, while a foreign key icon links the displayed table to a display of another table in the entity relationship diagram containing the foreign key. Dashed or dotted lines and dot or diamond terminators associated with the foreign key icon described the relationship between the displayed table and the linked table. A constraint icon links the displayed table to a display of the constraint information for an entity.

Abstract: The present invention includes a method of providing data to a memory device to be read at a first frequency comprising the steps of writing data to a memory device at a second frequency; blocking the writing of data after a predetermined amount of data is written; and writing data to the memory device in response to an address. Also included is a monitor circuit comprising a monitor state machine coupled to receive inputs including a comparison result, count signals and a load enable, and configured to output a data enable signal in response to the inputs.

Abstract: An on-chip driver is described for applications voltage output signals are desired from a digital sub-micron CMOS integrated circuit. The driver includes a signal buffer, signal level shifter, output pull-up, and an output pull-down. The signal buffer is coupled to a digital CMOS input for generating a corresponding buffered signal that is received by both the output-up down and the level shifter. The output pull-down is responsive to the buffered signal and operates to pull the output of the driver to a low voltage level of about 0 volts when the digital CMOS input is at a low logic state. Further, the level shifter is responsive to the buffered signal for generating a voltage shifted signal that is received by the pull-up which pulls the output of the driver to a high voltage level of 2.5 volts or greater when the digital CMOS input is at a high logic state.