Abstract: The outer surface of the cartridge sleeve is provided with features which increase the frictional coefficient between the cartridge sleeve and a tolerance ring placed around the cartridge. The cartridge and ring are then press-fit into the actuator bore together. The increased friction between the cartridge and ring prevents slip between them, eliminating the need to increase compressive forces between the ring and the bore and bearing.

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 includes a base and a disc rotatably attached to the base. The disc drive also includes an actuator assembly rotatably attached to said base and a device for moving the actuator assembly. The actuator assembly includes a transducer head in a transducing relationship with respect to the disc. The disc drive includes a disc drive controller for controlling movement of the actuator during track follow and track seek operations. The disc drive controller monitors the actuator during seek operations. The disc drive controller further computes a maximum average settle time from the monitored settle times. The dis drive controller further compares the maximum average settle time to a predetermined threshold value, and issues a command signal to adjust seek profile parameters of the disc drive to eliminate resonance in the actuator arm during a seek operation.

Abstract: The invention relates to apparatus and method that provide an improved media codeword and which can distinguish an uncorrectable data error from a wrong block address error and permit the address to be recovered from readback data. In accordance with one embodiment of the invention, method for generating parity is provided in which a sequences representing address and data are received. The address sequence is multiplied by a set of multiplier symbols to generate a first sequence of product symbols. A first portion is added to the data sequence prior to generating a first parity sequence and second portion is added directly to the first parity sequence to generate the final parity sequence. A corresponding method of generating syndromes from readback data is provided. System and apparatus incorporating the inventive method are also provided.

Abstract: Disclosed is a printed circuit board (PCB) layout for increasing the ability of the PCB to transfer heat away from a component mounted thereon. The locations of signal vias in the PCB are selected so as to define continuous pathways in a PCB heat sink layer. This allows heat to be effectively conducted away from thermal vias connected to heat sink layer, thereby preventing PCB-mounted components from overheating.

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: Disc drives are made with an actuator designed with at least one asymmetrical arm having two masses that move out of phase. The arm is modified by removing a portion of the higher-energy (longitudinal) side, the one with the greater total time-averaged strain energy. This modification reduces the phase difference between the first and the second arm, particularly for a relevant frequency range of interest. Disc drives made by this method exhibit a generally reduced out-of-phase motion, enhancing performance during seeking and track following, especially for arms with two heads that interact with surfaces of opposing discs.

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: 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 inertial latch that reduces the likelihood of damage due to secondary bouncing of the latch off of the actuator. An information system including a disc drive having a inertial lock including a latch and a latch receiver. The latch receiver located on the latch end of an actuator having a plurality of mating surfaces that engage with the latch. The latch may also have a plurality of teeth defining mating surfaces. The plurality of teeth may define a plurality of notches and opposed pairs of mating surfaces. The opposed pairs of mating surfaces may have a first mating surface and a second mating surface. The latch may have a latch point with opposed sides having a first opposed side and a second opposed side. The first mating surface may be engagable with the first opposed side and the second mating surface may be engagable with the second opposed side.

Abstract: A method of pre-processing sampled data prior to estimating the peak amplitude of a pulse includes averaging of two adjacent sample values. Pre-processing makes the peak amplitude estimation less sensitive to the sampling phase relative to the peak position and consequently allows for the use of a lower sampling period relative to the full-width-half-maximum pulse width for a given peak estimation accuracy. The method incorporates a step in which a base line offset signal is subtracted from an estimated peak value, and multiplying the consequent pulse peak amplitude estimate by a predetermined constant in order to compensate for a systematic change in a final peak amplitude estimate. The multiplying constant may have a value derived from estimated peak values of other detected pulses in order to compensate for a systematic change in the peak amplitude estimate.

Abstract: An actuator assembly suitable for a disc drive with at least one rotating disc for storing information. The actuator assembly has an actuator body having a mounting opening with at least a portion of the mounting opening being threaded and a bearing cartridge having an outer surface with at least a portion of the outer surface being threaded. The bearing cartridge is threadably received within the mounting opening of the actuator body so that the actuator body is releasably secured to the bearing cartridge. A method for securing an actuator body to a bearing cartridge in an actuator assembly of a disc drive is also provided.

Abstract: A system for evaluating a head stack assembly used in an optical or optically assisted hard drive is provided. The system utilizes a reflective surface that is provided in a forward and return optical path that includes an optical head and associated optical components.

Abstract: A voice coil for a head positional assembly of a disc drive. The voice coil including a dampener which dampens vibrations occurring in the voice coil. The dampener includes a constraint material and a viscoelastic material.

Abstract: A fiber-channel loop interface circuit that includes a dedicated transmit-frame buffer for loop initialization and responses (“responses” are non-data frames sent in response to commands or inquiries from other nodes). Having a dedicated transmit-frame buffer allows one port of a dual-port node to be transmitting initialization or response frames while another port is transmitting data frames, response frames, or initialization frames. Either or both ports can also be simultaneously receiving frames. The system includes a channel node having dual ports, each supporting a fiber-channel arbitrated-loop serial communications channel, and dedicated frame buffers within the channel node for loop initialization and responses. In some embodiments, the dedicated frame buffers are configured as on-chip buffers and include: two inbound non-data buffers coupled to the two ports, a data-frame buffer coupled to both ports, and an outbound transmit-frame buffer coupled to at least one of the ports.

Abstract: An apparatus and method for efficient defect management in a magneto-optical data storage system store a map of current and predicted defective physical addresses of a recording disk, and then skips defective data wedges to more completely utilize the non-defective recording surface area available for a given track. The invention also stores groups of physical addresses that share defects to decrease the number of entries in the map of defective physical addresses, and also to increase the effective defect management capacity of existing hardware and software.

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: Disclosed is a non-contact magnetic latch mechanism for holding a disc drive actuator in its park position. The latch includes a magnetically permeable element coupled to the actuator. The magnetically permeable element is positioned so as to be attracted to the magnetic field produced by the actuator voice coil magnets when the actuator is in or near its park position. The size, shape and location of the magnet may be selected so as to vary the latch torque and the range of influence of the latch on the actuator.

Abstract: Apparatus and method for cooling the actuator coil with a suitable heat sink structure. The heat sink thermally couples the coil to one or more of the head-carrying arms, which are positioned close enough to the disc stack that rotation of the stack cools them. In one embodiment, a gap is formed between the coil and a thermal conduit, and the gap is made wide enough to allow a majority of the gap to be filed with a solid dielectric. Another embodiment is a method for controlling the minimum gap thickness. In yet another embodiment, a rotary actuator includes a heat conduit with a concave surface for bonding to the coil, increasing rigidity and thermal conduction.