摘要:
In an idle state, servo information from all sectors is not used, but the servo information from every other sector or from every three or more sectors is used so that head positioning can be performed with only a minimum amount of servo information. The power to the electric circuitry of a write or read system and a servo system, which is not needed in the idle state, is interrupted, from the arrival of the selected servo information to the arrival of the next selected servo information, by a power control signal generated in accordance with the timing of the sectors. The power consumption can be reduced by the amount corresponding to turning off the circuitry not needed, plus the amount needed for computing for position control.
摘要:
A method and apparatus, in a direct access storage device including a head positioned for interaction with a data storage medium mounted on a rotating spindle, an actuator for positioning the head, and a servo control loop for positioning the actuator. The improvement comprises: a narrow band gain enhancing filter for connection in the servo control loop. The filter has a response frequency related to the rotational frequency of the spindle. The filter has programmable initial states. Also provided is a switch for switching in the narrow band filter as the head approaches a target position on the data storage medium. Initial states of the filter are determined and supplied to program the filter. At least one additional filter having a peak response frequency at a harmonic of the frequency of rotation of the spindle, may be provided. Initial states of the additional filters are determined and supplied to program the additional filter. The filter may include successive delay circuits for inputs to the filter, which circuits provide delayed outputs; multipliers for multiplying selected delayed outputs by a constant; and a summer for summing the delay outputs after the delayed outputs are multiplied by the multipliers. The initial states may be stored as phase, frequency and amplitude of a sine function.
摘要:
A disk drive with reduced seek acoustic noise and a method for implementation, without any additional hardware or mechanical modifications to the actuator includes a filter such that servo-loop stability is unaffected. The filter is inserted outside the existing servo loop to reshape the existing velocity profile in real time and to facilitate the suppression of forcing components that produce seek acoustics. A weighting factor may be used to provide a weighted average of the filtered and unfiltered velocity reference signal to the servo loop so that at the end of a track seek operation, the unfiltered reference signal is applied to the velocity servo, and there is almost no change in settle-out performance when the target track is reached. It is not necessary to store large volumes of velocity profile data to deal with different seek lengths.
摘要:
The present invention relates to a method and apparatus for writing servo tracks of a magnetic disk unit, and has an object of providing a servo track writing method and apparatus which can reduce a mechanical vibration of a head in the steady state and can shorten a settling time of the system. A detecting face is set in the vicinity of a head arm end portion 22 of a magnetic disk unit 2, and a capacitance probe 28 is provided as a gap detecting means for detecting a gap in a head moving direction between the detecting face and the head arm end portion 22. Further provided are a rotary positioner 26 as a positioning means for moving the capacitance probe 28 in the head moving direction to position it at a target position, and a head drive system control means for moving a head 14 of the magnetic disk unit 2 so that the gap is kept constant, to position the head 14 at a predetermined servo track writing position.
摘要:
A method for predicting and avoiding data errors by predicting disk drive read-write inhibit requirements in response to at least two parameters including a head position error and velocity with respect to the track centerline. A write or read inhibit signal is generated in response to selected combinations of these parameters to minimize soft read errors arising from track misregistration and to avoid hard errors arising from overwriting data recorded in an adjacent track. The read and write inhibit strategy is described as a pair of linguistic control rules suitable for implementation in a Fuzzy Logic Controller.
摘要:
In a direct access storage device including a rotating disk, a head positioned for interaction with said disk, an actuator for carrying said head and a servo system for operating said actuator so as to follow a substantially circular track on said disk by responding to a position error signal, a method for reducing response of the servo system to radial runout of the circular tracks, comprising the steps of obtaining radial runout data; filtering the data; storing the filtered data; subtracting the filtered data from the position error signal to obtain a corrected position error signal; and using the corrected position error signal to control the servo system. A direct access storage device in accordance with the invention includes means for obtaining radial runout data; means for filtering the data; means for storing the filtered data; means for subtracting the filtered data from the position error signal to obtain a corrected position error signal; and means for controlling the servo system using the corrected position error signal.
摘要:
A direct access storage device and a method of operation thereof where the output of the circuit which controls energy to the position actuator for the head may be changed at times between receipt of sequential position error signals from the medium. Instead of waiting for the next position error signal, a computation is done based on at least the current position and the desired position of the head as to when the head velocity will be equal to a desired velocity. The optimum time to switch is estimated, the energy required to achieve a predetermined velocity and a predetermined offset with respect to the desired position are computed, and operation is conducted accordingly. The amount of energy may again be changed at a time subsequent to the estimated time. The predetermined velocity and the predetermined offset may be zero or may have values other than zero in accordance with the requirements of the track following controller.
摘要:
In a direct access storage device having a head for interaction with a storage medium and a moving actuator on which the head is mounted, the improvement comprises a compound bearing system for the actuator, the bearing system including a first bearing of low friction for small movements of the actuator; and a second bearing of higher friction for coarse movements of the actuator. The storage medium is preferably a rotating magnetic disk having a series of concentric circular tracks. A single servo system drives the actuator so that the head follows a selected track with motion of the first bearing, and movement of the head to a new track causes motion of the second bearing. Preferably the first bearing is a flex bearing and the second bearing is a ball bearing.
摘要:
An apparatus (and a method for producing the same) for preventing internal vibrations produced as a result of rotary motion at a predetermined frequency within a device mounted in an enclosure from being translated into resulting rotary motion of the device comprises n vibration isolation mounts located between the device and the enclosure, said vibration isolation mounts having stiffness characteristics and being positioned so that rotational motion of the device at the frequency of the rotary motion is eliminated. The vibration isolation mounts are arranged and configured so that when the rotary motion produces linear and rotational forces, the net moment of all forces about the center of gravity of the device is equal to zero. The vibration isolation mounts may be isotropic. The isolation mounts may have different stiffness's. Three or more mounts may be used. Alternatively, the vibration isolation mounts may have the same stiffness's but their positions may be varied. An additional mass may be added to change the location of the center of gravity of the device. The vibration isolation mounts are preferably comprised of a material which provides damping of approximately ten percent of critical damping.
摘要:
In a computer apparatus including an enclosure and a direct access storage device mounted within the enclosure, a mounting apparatus for the direct access storage device including: a plurality of a relatively rigid shock isolators and at least one stress sensor mounted in series with are of said shock isolators and disposed between the enclosure and the direct access storage device. The enclosure may include a user frame and the mounting apparatus may be disposed between the direct access storage device and the frame. There may be one stress sensor for each of the shock isolators. The shock isolators may be coupled to the direct access storage device. Each stress sensor may include a piezoelectric element. Preferably the shock isolators are rigid enough so that the resonant frequency of said mounting apparatus is at least 800 Hz, but can be 800 Hz or higher.