Abstract: Disclosed is a magnetic encoder for determining a position of a first object relative to a second object. The encoder comprises a first magnetic member, a second magnetic member and a sensor member. The sensor member comprises a first sensor for measuring a change in magnetic field of the first magnetic member for deducing an unsigned absolute position of the first object relative to the second object, and a second sensor for measuring a change in magnetic field of the second magnetic member for deducing a sign for the unsigned absolute position. The first magnetic member and first sensor are coupled to respectively different ones of the first object and second object, and the second magnetic member and second sensor are coupled to respectively different ones of the first object and second object.

Abstract: A reader structure, a method of biasing a free layer of a reader structure, and a read head are provided, the reader structure comprises a free layer having a reader edge for interacting with and being proximal to a magnetic media; a first magnetic bias member and a second magnetic bias member each provided adjacent to the free layer, the first and second magnetic bias members being configured to have a first magnetisation direction which is substantially parallel to the reader edge; an additional bias member disposed adjacent to the free layer, the additional bias member further being located proximal to at least one of the first magnetic bias member and the second magnetic bias member, and the additional bias member being configured to have a magnetisation direction that is substantially orthogonal to the first magnetisation direction.

Abstract: In various embodiments, a magnetic medium may be provided. The magnetic medium may include a substrate. The substrate may include a servo layer over the substrate. The servo layer may include a cap layer having a first coercivity. The servo layer may also include a granular layer having a second coercivity greater than the first coercivity. The servo layer may also include an intervening layer between the cap layer and the granular layer.

Abstract: Magnetic disk, method of track following on a magnetic disk, and method of writing a servo pattern in a dedicated servo layer of a magnetic disk. The magnetic disk comprises a servo pattern in a dedicated servo layer of the magnetic disk, the servo pattern having a first burst A and a second burst B arranged to be within one period of a servo sample, each of burst A and burst B comprising DC+ and DC? magnetic bursts; wherein a center of the DC+/DC? bursts of burst B is shifted relative to the DC+/DC? bursts of burst A in a substantially radial direction of the magnetic disk.

Abstract: Magnetic disk, method of track following on a magnetic disk, and method of writing a servo pattern in a dedicated servo layer of a magnetic disk. The magnetic disk comprises a servo pattern in a dedicated servo layer of the magnetic disk, the servo pattern having a first burst A and a second burst B arranged to be within one period of a servo sample, each of burst A and burst B comprising DC+ and DC? magnetic bursts; wherein a center of the DC+/DC? bursts of burst B is shifted relative to the DC+/DC? bursts of burst A in a substantially radial direction of the magnetic disk.

Abstract: In various embodiments, a magnetic medium may be provided. The magnetic medium may include a substrate. The substrate may include a servo layer over the substrate. The servo layer may include a cap layer having a first coercivity. The servo layer may also include a granular layer having a second coercivity greater than the first coercivity. The servo layer may also include an intervening layer between the cap layer and the granular layer.

Abstract: A system including a write head, a read head, a mixer, and a filter. The write head is configured to write a pattern on a track of a medium of a hard disk drive, wherein the pattern has a first frequency. The read head is configured to read the pattern written on the track of the medium of the hard disk drive. The mixer is configured to mix a first signal generated by reading the pattern with a second signal to obtain a mixed signal. The second signal has a second frequency, and wherein the second frequency is different than the first frequency. The filter is configured to filter the mixed signal to determine a relative head-to-disk speed. The filter has a parameter selected based on a difference between the first frequency and the second frequency.

Abstract: In the present disclosure, a recording medium and a method of preparing a recording medium is provided. In a recording medium, a first annular servo track can be provided on a first layer of the recording medium, and second annular servo track can be provided on the first layer of the recording medium. The second annular servo track can be adjacent to the first annular servo track. In the recording medium, the first annular servo track and the second annular servo track are magnetically polarized and are magnetically opposing in polarity. A corresponding method of preparing a recording medium is provided.

Abstract: A servo system for writing servo information on a recording medium of a hard disk drive and for determining head position based on the servo information with a tracking accuracy, the servo system including a first magnetic head and a servo writer. The servo writer is configured to write the servo information on the recording medium by forming, using the first magnetic head, a first servo pattern comprising a servo burst pattern on a segment of a first track of a first layer of the recording medium; and by forming a second servo pattern comprising addressing information on a segment of a second track of a second layer of the recording medium. The second track is arranged half a width of the first track from the first track to increase the tracking accuracy of the servo system.

Abstract: According to various embodiments, a method for reading data from a storage medium using a reader, wherein the reader includes at least one reader head, may be provided, wherein the storage medium includes a plurality of tracks. The method may include: reading a first signal with a reader head of the reader at a pre-determined position of the storage medium; reading a second signal with a reader head of the reader at the pre-determined position of the storage medium; and determining data stored at the pre-determined position of the storage medium based on the first signal and based on the second signal.

Abstract: A system for reading data from a storage medium. The system includes a reader and a data determination circuit. The reader is configured to receive a first signal from a first position relative to the storage medium and read a second signal from a second position relative to the storage medium. Each of the first signal and the second signal includes a combination of first data stored in a first track and second data stored in a second track. The data determination circuit is configured to determine third data stored at a predetermined position using the combination of the first data stored in the first track and the second data stored in the second track as received in the first signal and the combination of the first data stored in the first track and the second data stored in the second track as received in the second signal.

Abstract: A servo system for writing servo information on a recording medium of a hard disk drive and for determining head position based on the servo information with a tracking accuracy, the servo system including a first magnetic head and a servo writer. The servo writer is configured to write the servo information on the recording medium by forming, using the first magnetic head, a first servo pattern comprising a servo burst pattern on a segment of a first track of a first layer of the recording medium; and by forming a second servo pattern comprising addressing information on a segment of a second track of a second layer of the recording medium. The second track is arranged half a width of the first track from the first track to increase the tracking accuracy of the servo system.

Abstract: According to an embodiment of the present invention, a data storage device comprising a motor having a stator is disclosed. The stator may include a substrate having a first surface and a second surface opposite to the first surface; and a n-phase winding arrangement having n phase windings; wherein each phase winding comprises m flat fractional-pitch coils arranged on the first surface of the substrate such that the coils are spaced apart uniformly along a closed loop and connected in series; wherein each coil together with an angular section of the substrate between the coil and an adjacent coil of the same phase winding defines a stator pole-pair; and wherein m is an integer larger than 1.

Abstract: A system for reading data from a storage medium. The system includes a reader and a data determination circuit. The reader is configured to receive a first signal from a first position relative to the storage medium and read a second signal from a second position relative to the storage medium. Each of the first signal and the second signal includes a combination of first data stored in a first track and second data stored in a second track. The data determination circuit is configured to determine third data stored at a predetermined position using the combination of the first data stored in the first track and the second data stored in the second track as received in the first signal and the combination of the first data stored in the first track and the second data stored in the second track as received in the second signal.

Abstract: A system including a write head, a read head, a mixer, and a filter. The write head is configured to write a pattern on a track of a medium of a hard disk drive, wherein the pattern has a first frequency. The read head is configured to read the pattern written on the track of the medium of the hard disk drive. The mixer is configured to mix a first signal generated by reading the pattern with a second signal to obtain a mixed signal. The second signal has a second frequency, and wherein the second frequency is different than the first frequency. The filter is configured to filter the mixed signal to determine a relative head-to-disk speed. The filter has a parameter selected based on a difference between the first frequency and the second frequency.

Abstract: According to embodiments of the present invention, a method for providing a synchronization signal for at least one of a read operation or a write operation carried out by means of a head in a data storage device is provided. The method includes obtaining a readback servo signal from a storage medium of the data storage device by means of the head, the readback servo signal having at least one frequency associated with a servo track of the storage medium, frequency mixing the readback servo signal with a local signal having a local frequency to provide a frequency mixed signal, and filtering the frequency mixed signal to provide the synchronization signal for at least one of the read operation or the write operation. According to further embodiments of the present invention, a data storage device is also provided.

Abstract: A method for measuring a change in a spacing between a head and a storage medium of a data storage system. The method includes obtaining a first readback signal from the storage medium using the head at a first spacing between the head and the storage medium, determining a first power spectrum density over a frequency range from the obtained first readback signal, obtaining a second readback signal from the storage medium using the head at a second spacing between the head and the storage medium, determining a second power spectrum density over the frequency range from the obtained second readback signal, and providing a measurement indicative of the change in the spacing based on the determined first power spectrum density and the determined second power spectrum density. A data storage system is also provided.

Abstract: In various embodiments, a method of writing servo information to a recording medium may be provided. The method include forming a first servo pattern (including a servo burst pattern) on a segment of a first track of a first layer of the recording medium, the first track having a track width. The method may further include forming a second servo pattern (including addressing information) on a segment of a second track of a second layer of the recording medium. The second track is arranged from the first track by half the track width.

Abstract: According to various embodiments, a method for reading data from a storage medium using a reader may be provided. The method may include: reading a first signal with a reader head of the reader at a first position of the storage medium; reading a second signal with a reader head of the reader at a second position of the storage medium; and determining data stored at a pre-determined position of the storage medium based on the first signal and based on the second signal.

Abstract: Methods and architecture for monitoring hard disk drive operation is provided. The hard disk drive system provided includes a spindle, a head and a disk with a disk medium including a buried servo layer having a first frequency of data on a first track and a second frequency of data on a second track, the second track adjacent to the first track. The method includes the steps of writing a wide track pattern having a predetermined frequency on a track of a hard disk drive medium, generating a readback signal by reading the pattern from the track, processing the readback signal by mixing the readback signal with a reference signal to obtain a mixed signal having a summed signal and a difference signal, and filtering the mixed signal by a filter centered around the difference signal to generate a measurement signal corresponding to a relative speed change of the spindle and a head-to-disk motion.