A method of decoding a codeword that satisfies a k constraint into output data includes, using a decoder of a hard disk drive system, converting each bit of the codeword in Non-Return-to-Zero format, extracting, from the converted codeword, a plurality of data blocks comprising a first data block and a plurality of remaining data blocks, performing a first analysis on the plurality of data blocks for modifying each of the plurality of data blocks that satisfies a first predetermined criterion, and performing a second analysis on the plurality of data blocks after the first analysis for modifying each of the plurality of data blocks that satisfies a second predetermined criterion to obtain the output data.

Holographic data storage system and method are disclosed. The holographic data storage system includes an encoder configured to convert input data into a codeword, a storage unit configured to store the converted codeword, and a decoder configured to convert the stored codeword into output data. Here, the encoder converts the input data having 8 bits into the codeword in (5×2) matrix.

This disclosure describes codes and techniques for magnetic recording. The coding schemes decrease bit error rates by decreasing total transitions in the encoded binary data compared to conventional codes. Additionally, instead of relying on a single coding scheme, an encoder and decoder are configured to switch between different coding schemes. By so doing, a variety of the coding schemes allows the encoded binary data to have a smaller bit error rate than a single coding scheme and have a maximum run-length less than or equal to a maximum run-length limitation of a magnetic disk.

The present disclosure describes aspects of pulse-based writing for magnetic storage media. In some aspects, a pulse-based writer of magnetic storage media determines that a string of data bits having a same polarity corresponds to a magnet longer than a threshold associated with a magnetic media writer. The pulse-based writer inserts, into the string of data bits, a transition to a polarity opposite to the same polarity of the string of data bits. The string of data bits including the inserted transition is then transmitted to the magnetic media writer to cause a write head of the writer to pulse while writing the magnet to magnetic storage media. Various aspects may also implement a control signal to mask a transition or control polarity of the magnetic media writer. By so doing, magnets may be written to the magnetic storage media more efficiently or with less distortion to neighboring tracks.

The present disclosure describes aspects of pulse-based writing for magnetic storage media. In some aspects, a pulse-based writer of magnetic storage media determines that a string of data bits having a same polarity corresponds to a magnet longer than a threshold associated with a magnetic media writer. The pulse-based writer inserts, into the string of data bits, a transition to a polarity opposite to the same polarity of the string of data bits. The string of data bits including the inserted transition is then transmitted to the magnetic media writer to cause a write head of the writer to pulse while writing the magnet to magnetic storage media. Various aspects may also implement a control signal to mask a transition or control polarity of the magnetic media writer. By so doing, magnets may be written to the magnetic storage media more efficiently or with less distortion to neighboring tracks.

The present disclosure describes aspects of pulse-based writing for magnetic storage media. In some aspects, a pulse-based writer of magnetic storage media determines that a string of data bits having a same polarity corresponds to a magnet longer than a threshold associated with a magnetic media writer. The pulse-based writer inserts, into the string of data bits, a transition to a polarity opposite to the same polarity of the string of data bits. The string of data bits including the inserted transition is then transmitted to the magnetic media writer to cause a write head of the writer to pulse while writing the magnet to magnetic storage media. Various aspects may also implement a control signal to mask a transition or control polarity of the magnetic media writer. By so doing, magnets may be written to the magnetic storage media more efficiently or with less distortion to neighboring tracks.

The present disclosure describes aspects of pulse-based writing for magnetic storage media. In some aspects, a pulse-based writer of magnetic storage media determines that a string of data bits having a same polarity corresponds to a magnet longer than a threshold associated with a magnetic media writer. The pulse-based writer inserts, into the string of data bits, a transition to a polarity opposite to the same polarity of the string of data bits. The string of data bits including the inserted transition is then transmitted to the magnetic media writer to cause a write head of the writer to pulse while writing the magnet to magnetic storage media. Various aspects may also implement a control signal to mask a transition or control polarity of the magnetic media writer. By so doing, magnets may be written to the magnetic storage media more efficiently or with less distortion to neighboring tracks.

A preamplifier has a pre-compensation circuit that optimizes the write current in a low current range of less than 30 mA. The pre-compensation circuit maintains the peak current with a high overshoot current amplitude for achieving an optimized areal density capability to equalize the erase widths for the bit lengths of the encoded data with bit lengths greater than three clock time periods with encoded data with a bit length of the two clock time period. Alternately, the pre-compensation circuit has an overshoot generator that determines the optimum amplitude of the overshoot current for the bit-lengths for the encoded data. An overshoot data synchronizer is connected to a read current preamplifier to receive a pseudorandom read data signal that is applied to the overshoot generator to enable the different overshoot current amplitude depending on the bit length of the encoded data. The pre-compensated data current is transferred to the write head.

The present disclosure describes aspects of pulse-based writing for magnetic storage media. In some aspects, a pulse-based writer of magnetic storage media determines that a string of data bits having a same polarity corresponds to a magnet longer than a threshold associated with a magnetic media writer. The pulse-based writer inserts, into the string of data bits, a transition to a polarity opposite to the same polarity of the string of data bits. The string of data bits including the inserted transition is then transmitted to the magnetic media writer to cause a write head of the writer to pulse while writing the magnet to magnetic storage media. Various aspects may also implement a control signal to mask a transition or control polarity of the magnetic media writer. By so doing, magnets may be written to the magnetic storage media more efficiently or with less distortion to neighboring tracks.

According to one embodiment, a magnetic disk device includes a magnetic disk including at least one servo zone that includes a first data storage track with a first servo pattern having a first frequency and a second data storage track with a second servo pattern having a second frequency, wherein the first data storage track is located closer to an outer diameter of the magnetic disk than the first data storage track and the first frequency is greater than the second frequency; a magnetic head that faces the magnetic disk; and a zone servo switching unit that switches a servo pattern frequency employed to position the magnetic head in a radial direction based on a radial position of the magnetic head.