Systems and methods are disclosed for detecting shingled overwrite errors. When a read error is encountered when reading from shingled recording tracks, a processor may determine whether the read error is an error caused by shingled overwriting. The processor may determine whether the read error is caused by shingled overwriting by determining read signal quality of one or more sectors preceding the read error, such as based on a bit error count or bit error ratio (BER), and comparing the read signal quality to a threshold value. The processor may determine that the read error is caused by shingled overwriting when the read signal quality value is lower than the threshold.

Systems and methods for logically organizing data for storage and recovery on a data storage medium using a multi-level format are described. Embodiments include systems and methods for protecting data stored on a data storage medium so that the data may be recovered without errors.

A data storage device includes a hard disk drive coupled to a printed circuit board (PCB), a volatile memory device coupled to the PCB, a non-volatile memory device coupled to the PCB, and a controller coupled to the PCB, such that the controller is in communication with the hard disk drive, the volatile memory device, and the non-volatile memory device. The controller is configured to identify patterns and/or structures of metadata for the hard disk drive, perform one or more of the following to the metadata to tailor the metadata: data shaping, content aware decoding, adaptive data trimming, and/or adaptive metablock sizing, and write the tailored metadata to the non-volatile memory device. The metadata is at least one of repeatable run out metadata, positioning error signal metadata, adjacent track interference metadata, and/or emergency power off metadata.

According to one embodiment, a magnetic disk device includes a disk including a zone servo boundary area including a first area of a first servo frequency, a second area of a second servo frequency, and a third area of the first servo frequency, in a servo area, a head, and a controller demodulating first servo data of the first area to derive a position of the head and demodulating first corrected data of the third area to correct the position of the head. The first area, the second area, and the third area are aligned in order in a traveling direction. The first area and the second area are adjacent to each other in a circumferential direction of the disk. The second area and the third area are adjacent to each other in the circumferential direction.

The present application provides a data storage method, a data storage apparatus and a storage system, wherein the method includes: determining a data type of to-be-stored data when the to-be-stored data is obtained (S410); determining a target storage area with a data type same as that of the to-be-stored data based on the data type of data stored in each storage area in the SMR disk (S420); determining in the target storage area a target storage block into which the to-be-stored data is to be written (S430); generating the main index information and backup index information of the to-be-stored data based on the identifier of the target storage block (S440); generating the database index information of the to-be-stored data based on the to-be-stored data and the identifier of the target storage block (S450); and writing the to-be-stored data and the backup index information of the to-be-stored data into the target storage block, writing the main index information of the to-be-stored data into the CMR area or the non-SMR disk, and writing the database index information of the to-be-stored data into the non-SMR

According to an embodiment, a magnetic disk has a plurality of second servo sectors and a plurality of third servo sectors each arranged between two second servo sectors of the plurality of second servo sectors, in which the second and third servo sectors are arranged in a circumferential direction. A controller performs a first demodulation for detecting a servo mark and demodulating a burst pattern on the servo data in each second servo sector. The controller performs a second demodulation for demodulating the burst pattern without detecting the servo mark, on the servo data in each third servo sector. The controller performs the second demodulation on the servo data in a fourth servo sector which is one of the plurality of second servo sectors in a case where the detection of the servo mark fails when the first demodulation is performed on the servo data in the fourth servo sector.

There is provided a recording apparatus, a recording method, a reproduction apparatus, a reproduction method, a recording medium, an encoding apparatus, and a decoding apparatus which enable recording or reproduction to be easily implemented at high line density. User data is encoded into a multilevel edge code, and a multilevel code whose value changes in accordance with the multilevel edge code is recorded. The multilevel edge code is generated through state transition of a code generation model which includes a state representing the number of times that zero is consecutive corresponding to a number of ways of the number of times that zero is consecutive, which is the number of times that an edge of 0 is consecutive among edges representing a change amount from an immediately preceding value of the multilevel code of an ML value which is equal to or greater than 3, and which transitions to a state representing the number of times that zero is consecutive including 0 in a case where 0 is output, and transitions to a state representing that the number of times that zero is consecutive is 0 times in a case where one of 1 to ML−1 is output.

A magnetic disk device includes a plurality of magnetic heads, a storage unit that stores a table storing, for each of the magnetic heads, a track skew value obtained by adding a head shared value and a head unique value, and a control unit that reads out the track skew value corresponding to one of the magnetic heads to be operated from the table and performs seek control.

A controller provides a plurality of first sections with numerical information on a first scale. The plurality of first sections are obtained by dividing a recording surface of a magnetic disk in units of first memory areas in each of which a first volume of data can be written by an SMR method. The first scale corresponds to a sequence of the first sections. The controller provides a plurality of second sections with numerical information on a second scale. The plurality of second sections are obtained by dividing the recording surface of the magnetic disk in units of second memory areas in each of which the first volume of data can be written by a CMR method. The second scale corresponds to a sequence of the second sections. The controller executes a plurality of commands in order based on a numerical information on the first scale or the second scale.

A storage device includes a plurality of memory devices, and processing circuitry. The plurality of memory devices includes one or more hard disk drives. The processing circuitry is configured to inspect performance of the one or more hard disk drives at a predetermined timing; perform a first predetermined countermeasure processing, on a target hard disk drive out of the one or more hard disk drives whose performance has been determined to have fallen, in a case that the target hard disk drive is a shingled magnetic recording hard disk drive; and perform a second predetermined countermeasure processing, different from the first predetermined countermeasure processing, on the target hard disk drive, in a case that the target hard disk drive is not a shingled magnetic recording hard disk drive.