Abstract: A data storage device, data write method, and program to avoid extra power consumption and suppress a write error that may result from voltage variations. To write data onto a magnetic disk, a write circuit generates a write current that is to be supplied to a write head. The write circuit operates on a positive power supply voltage provided by a host computer, and on a negative power supply voltage generated by a programmable DC—DC converter mounted on a hard disk drive's card. The magnitude of the negative power supply voltage generated by the programmable DC—DC converter is varied in accordance with the temperature surrounding the magnetic disk. Further, the magnitude of the negative power supply voltage generated by the programmable DC—DC converter is varied in accordance with the magnitude of the positive power supply voltage supplied from the host computer.

Abstract: The invention is directed to servo techniques that make use of sequences of servo marks, rather than individual marks for generation of position error signals. In particular, random or pseudo-random sequences of servo marks may be recorded on the medium in an overlapping fashion. For example, a first sequence of marks and a second sequence of marks may overlap in the servo track. The second sequence may be substantially non-correlated with the first sequence, and may be recorded in an offset location along the track relative to the first sequence. Different correlators can be used to detect the different sequences, and position error signals can be generated based on timings associated with the detection of the first sequence relative to the second sequence.

Abstract: In a Maximum A posteriori Probability decoding (MAP decoding), a correlation and a deviation of noises for past and future states which depend on input signal patterns in past N bits and future Q bits are calculated by training by a noise correlation arithmetic operating unit 84 and they are stored. Upon reproduction, in a white noise arithmetic operating unit 91, white noise values for the past and future states in which colored noises are converted into white noises are obtained by using the stored correlation and deviation of the noises. In an input signal arithmetic operating unit 92, an input signal (channel information) ?c(yk|Smk) of the MAP decoding is calculated from the white noise values and the deviation for the past and future states. A likelihood in the MAP decoding is obtained from the input signal.

Abstract: Object of this invention is to provide a servo writer capable of automatically controlling record current amount supplied to a writing head for every kind of magnetic tape when writing a servo signal on many kinds of magnetic tapes. The servo writer for writing a servo signal on magnetic tape MT which is fed out from a feeding reel and taken-up by a take-up reel includes writing head H1 that writes a servo signal on the magnetic tape MT, inspection head H2 for reading the servo signal formed on the downstream side and written on the magnetic tape MT, servo signal inspection part 16 that inspects the servo signal read by the inspection head H2, and current amount control part 17 that controls the amount of record current supplied to the writing head H1 based on the inspection result in the servo signal inspection part 16.

Abstract: The invention enables a magnetic disk drive to be inserted and removed against an attraction force exerted by a magnetic force that is strong enough to erase data on a magnetic disk enclosed within a metal case. A converting mechanism comprising a ballscrew and a ballscrew nut bracket is provided that converts rotational motion of a handle into translational motion of an HDD holder; by rotating the handle, the HDD holder with the hard disk drive mounted thereon is moved in the inserting and removing directions by overcoming the attraction force being exerted by the magnetic field generated by means of a permanent magnet. An electric motor may be used to generate the rotational force.

Abstract: A data stream received by a hard disk drive (HDD) is organized into at least one cluster having data blocks and spare data blocks and that is equal in size to an integer multiple of the number of sectors in a track of a disk of the HDD. A variable-index writing technique is used to write each data block of a cluster to a corresponding sector of a track that is encountered by a head when the sector is not defective. A sector of the track is skipped during writing when the sector is defective. The number of spare data blocks in a portion of a cluster corresponding to a single track is reduced by the number of sectors that are skipped in the track so that the number of data blocks plus the number of remaining spare data blocks equals the number of sectors in a track.

Abstract: Methods and apparatus are provided for creating servo-tracks on the R-side of single-sided hard memory disks. The method includes placing two single-sided disks in a concentric contact merge orientation with the R-side of each disk facing outwardly. Two independent servo-track writers then position an independent transducer proximate each R-side and write desired servo-track data to the R-side surface of each disk. The disks are de-merged and either disk may be placed in any single-sided disk drive.

Abstract: A method to read information from a tape storage medium, where that tape includes a calibration region and a data region. The method uses a read channel having a first detection mode and a second detection mode. The method initializes the first detection mode and forms a calibration waveform comprising information read from the calibration region using the first detection mode. The method then defines a plurality of bit cell boundaries, initializes the second detection mode, and reads information from the data region using the second detection mode.

Abstract: A disk drive stores overhead information corresponding to multiple servo sectors within a dedicated data sector in a customer data region of a data storage disk. The overhead information includes servo data for which the information content does not depend upon the physical location of the data on the disk surface. During a data storage operation, the overhead data is read from the dedicated data sector and stored in a buffer memory within the disk drive. A portion of the overhead data is then retrieved from the buffer memory for each servo sector subsequently traversed by the transducer for use in performing a data processing task related to the servo sector.

Abstract: A disk writer writing servo data on a disk for an HDD. The disk writer includes a reference signal writer writing a reference signal on the disk along a track at a predetermined distance from an edge of the disk; and a servo writer including a reference signal detector detecting the reference signal written on the disk and a writer writing the servo data on the disk on the basis of a position where the reference signal is detected. With this configuration, the present invention provides a disk writer and a writing method thereof, capable of minimizing a positioning error of a start track of an HDD.

Abstract: A read processing method and a reproduction system for continuously reading out an audio/visual data from a storage medium. When a data cannot be read out from storage medium, a data having a predetermined pattern is transferred so as to prevent operational deadlock caused by an error data even when the audio/visual data is transferred continuously. This method enables to allow to transfer audio/visual data continuously. Also, an application for reproducing data enables to identify an error, enabling to avoid the application falling into a non-executable condition or the system falling into a hung-up condition. In addition, because whether a retry is needed is determined when error data is transferred, it becomes possible to avoid an unnecessary retry in reproducing audio/visual or the like.

Abstract: In a disk drive which executes data read operation or data write operation from or into a disk, its CPU determines whether or not the temperature environment of the disk drive is in the high temperature condition exceeding a specified value according to a temperature detection value from a temperature sensor. Under high temperature environment, the CPU aborts re-assignment processing including write operation mode other than ordinary write operation.

Abstract: A disk drive includes a disk, a voltage supply, a head stack assembly and a switching circuit. The head stack may include a coil portion that includes a coil assembly having first and second wound coils. The switching circuit is electrically coupled to the voltage supply and to the coil assembly, and is configured to selectively switch the first and second wound coils between a first configuration and a second different configuration in which the first wound coil is electrically in parallel with the second wound coil.

Abstract: Heretofore, when an error occurs during data reproduction, a retry is repeated until the error is corrected, which leaves a possibility of data transfer being not completed within a specified time. Only one piece of error information on uncorrected errors is informed to a host system even if the errors have occurred in a plurality of unit data. To solve the problem, a magnetic disk drive is provided which can transfer data within a specified time because the number of retries executed when errors occur is limited to a range that data transfer can be finished within a specified time. The disk drive generates error information regarding all errors caused in reproduction and communicates error information along with reproduced data to a host system. The disk drive is capable of concurrent execution of data processing that allows of errors and data processing that does not allow of errors without demanding that the disk drive be furnished with high performance.

Abstract: There is disclosed a disk drive provided with a function of suspending a read/write operation in the case where the magnetic field of the magnetic disturbance out of the predetermined range is generated. The disk drive has a head writing data to the disk, a sensor detecting a magnetic field with respect to the disk drive, and an actuator unloading the head from the surface of the disk to a retracting position outside of the disk when the detected magnetic field is out of a predetermined range.

Abstract: In order to solve a problem that it takes a long time to shift from a write mode to a read mode when there is a cross talk of an output signal of a recording head to a reproducing amplifier side, there is provided a reproducing amplifier including an amplifier circuit portion having a differential pair of transistors is provided with a switching circuit comprised of switches connected with resistors, which supply a bias voltage to each base of the differential pair of transistors, respectively in parallel. The switching circuit turns on for a write mode period and for a fixed period after a change from the write mode to a read mode to decrease the input impedance of the reproducing amplifier for the periods.

Abstract: The present invention may be embodied in a method for adjusting a servo sector detection delay time between detection windows in a disk drive. The disk drive includes a magnetic disk with a spiral track having contiguous storage segments. Each storage segment has a servo sector and a predetermined number of uniformly-sized data sectors. The storage segments are written at a relatively constant linear density along the spiral track. In the method, the magnetic disk is rotated at a constant angular velocity. A servo sector is detected. An adjustable delay time is provided for opening a window to detect a next servo sector. The window is opened after the adjustable delay time expires. A next servo sector is detected in the window. A time between the servo sector detections is measured and the adjustable delay time is adjusted based on the measured time.

Abstract: A method and apparatus for improving the settle time and thus, the transition from seek control to track following control in a disc drive system are provided. With the apparatus and method, two counters are provided—a consecutive counter and a non-consecutive counter. The consecutive counter counts consecutive samples that meet threshold requirements. The non-consecutive counter counts non-consecutive groups of consecutive samples that meet threshold requirements. When the consecutive counter reaches a first predetermined value, the non-consecutive counter is incremented and the consecutive counter is reset to zero. When the non-consecutive counter reaches a second predetermined value, a track following control mechanism is initiated to thereby transition from a seek control operation to a transitional control operation and finally a track following control operation.

Abstract: A main controller controls the current in an overshoot part included in the write current supplied from a write driver to a head in accordance with write data via an overshoot controller in accordance with the temperature detected by a temperature sensor.

Abstract: A repeatable run-out (RRO) detector employs one or more digital interpolators to interpolate asynchronous sample values representing an RRO address mark (AM) and RRO data, an asynchronous maximum-likelihood (AML) detector to detect the RRO AM, and a RRO data decoder to decode the RRO data. The AML detector employs an AML algorithm, such as a Viterbi algorithm, to detect the series of peaks of the RRO AM based on detection of the entire sequence of observed peaks. AML detection selects one of either the asynchronous or interpolated sample sequences that are closest in distance to the ideal RRO AM sample sequence. Once the RRO AM is detected, the AML detector provides a RRO AM found signal as well as the selected one of the sample sequences having the best phase for detecting and decoding the RRO data.