Abstract:
A storage device controller is configured to select one of multiple written track widths for a storage location based on a write attribute of data to be recorded at the storage location. According to one implementation, the storage device controller is further configured to select a power level for a heat-assisted magnetic recording (HAMR) device based on the write attribute.
Abstract:
An apparatus and method provide for performing, using a heat-assisted magnetic recording head, multiple sequential writes to a recording medium, and recording a metric of write performance for each of the writes. The apparatus and method further provide for calculating fluctuations in the metric, detecting whether the head has a laser mode hopping problem using the metric fluctuations, and categorizing a severity of the laser mode hopping problem.
Abstract:
Systems and methods of digital automatic power control are presented. A preamplifier circuit may include a digital-to-analog converter (DAC) circuit to sample a power signal, such as a from a laser power monitor. The preamplifier may store the sample in an internal preamplifier memory. The sample may be utilized to update a current output of the preamplifier that affects the power signal. These systems and methods may be particularly useful for lasers and heat-assisted magnetic recording (HAMR), which may be utilized during a read mode or a write mode of a HAMR data storage device.
Abstract:
A storage device includes a storage medium having a plurality of data tracks. At least one data track of the plurality of data tracks includes a number of super parity sectors. The number of super parity sectors selected for the at least one data tracks is selected based on a distance between an inner diameter of the storage medium and the data track. The number of super parity sectors provides error correction code for the at least one data track.
Abstract:
A method comprises storing a first laser current value in response to a photodetector sensing that a threshold current for a laser diode of a HAMR head has been reached, the photodetector situated proximate the laser diode. The method also comprises storing a second laser current value in response to a sensor sensing that the threshold current for the laser diode has been reached, the sensor situated away from the laser diode. The method further comprises determining a difference (delta) between the first and second laser current values, repeating the storing and determining processes during subsequent use of the laser diode, and detecting a change in the delta indicative of a malfunction of the head.
Abstract:
An apparatus comprises a heat-assisted magnetic recording head configured to write to and read from a magnetic recording medium. The head comprises a reader and a writer including a near-field transducer (NFT). The reader comprises a center which is laterally offset relative to a center of the writer to define a reader-writer offset (RWO) therebetween. A magnetic recording medium comprises a plurality of tracks. The plurality of tracks comprises at least one track used as a region to test for a shift in the RWO. A processor is coupled to the recording head and configured to detect the RWO shift.
Abstract:
A transducing head may be connected to a controller and positioned proximal a data storage medium. The controller can be connected to a wear level identification circuit and configured to identify a first data region of the data storage medium having a first wear level and a second data region of the data storage medium having a second wear level. The first and second wear levels can respectively correspond to different amounts of component degradation of the data storage device.
Abstract:
At least one laser input current is applied to a laser in a heat assisted magnetic recording device. Laser output power of the laser is measured at the at least one applied laser current. A relationship is characterized amongst temperature, applied laser input current and laser output power. Laser current is set to an optimal laser current as determined at manufacturing. A metric of recording performance is measured to determine if the relationship is acceptable.
Abstract:
A transducer is configured to interact with a magnetic storage medium, a first channel comprises a first sensor and first circuitry configured to adjust a plurality of first channel parameters, and a second channel comprises a second sensor and second circuitry configured to adjust a plurality of second channel parameters. The first and second channel parameters are independently adjustable by the first and second circuitry, respectively. A detector is coupled to the first and second channels, and configured to detect a head-medium interface event.
Abstract:
A system for DNA gene assembly that utilizes a DNA symbol library and a DNA linker library. The symbol library has a number of DNA symbols each having a first overhanging end and a second overhanging end different than and non-complimentary to the first end, the first and second ends being the same nucleotides for each DNA symbol. The linker library has pairs of DNA linkers, a first linker of a pair having a first end and a second end and a second linker of the pair having a first end and a second end, the first end of the first linker being the same nucleotides for each first linker and the second end of the second linker being the same nucleotides for each second linker, wherein the second end of the first linker and the first end of the second linker have complementary nucleotides. The first linker joins to the first end of a DNA symbol and the second linker joins to the second end of another DNA symbol.