Method and apparatus for recording data
First Claim
1. A data storage device including a read/write head and a magnetic disk which form the disk to head interface, the magnetic disk capable of retaining data pulses recorded at various frequencies, the amplitude of the readback voltage of a pulse train varying as a function of the selected frequency, the amplitude of the readback voltage of a pulse train recorded at the selected frequency divided by the amplitude of the readback voltage of a pulse train recorded at a lower frequency yielding the resolution, the magnetic system manufactured with disks formatted by a process comprising the steps of:
- determining a magnetic characteristic for the head to disk interface for each track on the magnetic disk; and
using the determined magnetic characteristic for each track to select a frequency for each track that will produce a substantially constant resolution in each track across the disk.
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Accused Products
Abstract
A method and apparatus for increasing the amount of data capable of being stored in a magnetic storage device is disclosed. Basically, a magnetic characteristic of the disk to head interface is measured at several locations on the disk. The frequency for writing and reading the data is optimized in terms of the required resolution and the magnetic measurement. The read and write modes are then varied, based upon the optimized frequency, such that data is written on the disk at a frequency substantially equal to the optimized frequency and read from a disk having data recorded at the optimized frequency.
84 Citations
27 Claims
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1. A data storage device including a read/write head and a magnetic disk which form the disk to head interface, the magnetic disk capable of retaining data pulses recorded at various frequencies, the amplitude of the readback voltage of a pulse train varying as a function of the selected frequency, the amplitude of the readback voltage of a pulse train recorded at the selected frequency divided by the amplitude of the readback voltage of a pulse train recorded at a lower frequency yielding the resolution, the magnetic system manufactured with disks formatted by a process comprising the steps of:
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determining a magnetic characteristic for the head to disk interface for each track on the magnetic disk; and using the determined magnetic characteristic for each track to select a frequency for each track that will produce a substantially constant resolution in each track across the disk. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of determining the read/write frequency for each track of a magnetic disk in a magnetic system which also includes a read/write head, the method comprising the steps of:
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determining a magnetic characteristic of the magnetic system for each track of the magnetic disk; selecting a first frequency for each track; determining the voltage amplitude as a function of time for a train of pulses occurring at the first frequency using the first frequency and the magnetic characteristic for the track; selecting a second frequency lesser than the first frequency; determining the voltage amplitude as a function of time for a train of pulses occurring at the second frequency using the magnetic characteristic for the track and the second frequency; dividing the value of the voltage amplitude as a function of time for the train of pulses occurring at the first frequency by the value of the voltage amplitude as a function of time for the train of pulses occurring at the second frequency to yield a value called the calculated resolution; selecting a desired resolution, the desired resolution having an associated error rate which is less than the specified error rate; and comparing the calculated value of the resolution to a desired value of resolution to determine if it is within a desired range of the desired value of the resolution. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15)
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16. A method for reading and writing data at an error rate less than the specified value in a data storage device including a magnetizable disk with tracks and a read/write head which form a disk to head interface, and a memory, the data storage device encoding data before recording and decoding data after reading according to a coding scheme, the data storage device capable of recording data through a range of frequencies, the highest frequency in the range related to the lowest frequency in the range by a constant which is a characteristic of the coding scheme being used, the amplitude of the readback voltage of the high frequency in the range divided by the voltage amplitude of the lowest frequency in the range yielding resolution, each resolution having a specific error rate associated therewith, the method comprising the steps of:
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determining a magnetic characteristic of the magnetic disk to read/write head interface for each track on a disk; dividing the selected high frequency by the constant for the particular coding scheme to produce the lowest frequency in the range for a track; determining the amplitude of the readback voltage for the selected high frequency and the lowest frequency in the range using the frequency and the magnetic characteristic; calculating the resolution; selecting a range of desired values of resolution, the error rates of the resolutions in the range being less than that specified; and determining if the calculated resolution falls within the range of desired values of resolution and if the calculated value of resolution is less than the desired range, subtracting a decrement of frequency from the selected frequency and recalculating the resolution, and if the calculated resolution is greater than the desired range of resolution adding an increment of frequency to the selected frequency. - View Dependent Claims (17, 18, 19, 20, 21)
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22. An apparatus for reading and writing data in a storage device having a read/write head and a magnetizable disk with tracks, the apparatus comprising:
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means for storing and recalling a track location and a read/write frequency for each track on the disk; means for determining the position of the read/write head; means for producing data pulses on the magnetizable disk at a frequency substantially equal to the frequency stored in the storing and recalling means which corresponds to the location determined by the position determining means; and means for reading data recorded at various frequencies from the magnetizable disk, the read frequency being substantially equal to the frequency stored in the storing and recalling means which corresponds to the location determined by the position determining means. - View Dependent Claims (23, 24, 25, 26, 27)
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Specification