Various implementations described herein are directed to technologies for providing error detection for a disk drive of a digital video recorder (DVR). Access data is measured according to a degree of usage of a disk drive of a DVR. The access data is stored. The stored access data is analyzed to detect performance degradation of the disk drive.

Various implementations described herein are directed to technologies for providing error detection for a disk drive of a digital video recorder (DVR). Access data is measured according to a degree of usage of a disk drive of a DVR. The access data is stored. The stored access data is analyzed to detect performance degradation of the disk drive.

To read data from a storage medium, a magnetization map of the data stored on at least one portion of the storage medium is obtained. The magnetization map is analyzed to obtain intermediate data corresponding to the data stored on the at least one portion of storage medium. Further, the intermediate data is converted into the user data based on format emulation of a data storage format of the storage medium. The conversion of the intermediate data includes decrypting the intermediate data to obtain the user data.

A system according to one embodiment includes a magnetic head having a plurality of sensors arranged to simultaneously read at least three immediately adjacent data tracks on a magnetic medium, wherein none of the sensors share more than one lead with any other of the sensors. Such embodiment may be implemented in a magnetic data storage system such as a disk drive system, which may include a magnetic head, a drive mechanism for passing a magnetic medium (e.g., hard disk) over the magnetic head, and a controller electrically coupled to the magnetic head.

A method for writing data onto a medium on which data are stored in tracks includes encoding the data into at least one codeword, and writing a respective portion of each of the at least one codeword onto respective different tracks on the medium. The writing may include writing a respective portion of each of the at least one codeword onto respective different adjacent tracks on the medium. Another method for reading data includes positioning a plurality of read heads to read codewords that have been written across multiple tracks of a medium. Each read head in the plurality of read heads reads a different portion of the first group of the multiple tracks, and where each different portion of the multiple tracks overlaps at least one other different portion of the multiple tracks. Signals are detected from the plurality of read heads, and the detected signals are decoded.

An optical information recording/reproduction device is capable of appropriately correcting the angle of a reference beam during data reproduction even when a wavelength deviation or an angle deviation in multiplexing and vertical directions of the reference beam occurs in a holographic memory recording medium. The optical information reproduction device has a laser light source that generates a reference beam; an image-capturing unit that detects a diffraction ray to be reproduced from the optical information recoding medium; and an optical detection unit that has at least two light-receiving surfaces and is used for detecting a diffraction ray reproduced by irradiating the reference beam on the optical information recording medium. The device also has a light-shielding unit that shields part of the diffraction ray detected by the optical detection unit; and an error signal calculation unit that generates an error signal from a detection signal outputted by the optical detection unit.

A magnetic disk apparatus of one of the embodiments stores read position dependency information on read signal quality of a data region at a first track and measures the read signal quality at a predetermined radial position in a second data region of a second track different from the first track. A positioning error of the second data region is determined based on the read position dependency information and the read signal quality at the predetermined radial position. Data is recorded in a recording target data region in a shingled recording so as to prevent data written in the second data region from being overwritten by data in a recording target data region adjacent to the second data region by using the determined positioning error.

In an optical disc apparatus that records and reproduces data onto and from an optical disc in units of predetermined block, an information divider divides the data so as to reduce an amount of the data included in each of blocks when a recording state of the optical disc does not satisfy a predetermined criterion, and reproduces recording data in units of the block by adding sub-information including a value indicating the amount of the data included in each of the blocks. An error-correction encoder circuit encodes the recording data in a first error-correction code format, and a recorder converts encoded recording data into a recording signal, and records the recording signal onto the optical disc. A quality evaluator circuit produces an evaluation value indicating a recording quality based on a result of reproducing the recording signal recorded on the optical disc.

According to one embodiment, a magnetic disk device includes a disk that has a track including a first servo sector and a second servo sector that is different from the first servo sector, a head that writes data to the disk and reads data from the disk, and a controller that records first signal strength record data related to a signal strength at which first target servo data that is a target of the first servo sector is read, and standardizes first signal strength data related to a signal strength at which the first target servo data is read when the first target servo data is read.

A mark corresponding to recording data is formed on an optical disk by: encoding the recording data in accordance with a modulation code and generating encoded data; classifying the encoded data by a combination of at least two of a mark length of a mark, a space length of a preceding space, the mark length of a preceding mark, and the space length of a succeeding space; setting a correction amount for adjusting the position of the start edge and the end edge of a recording pulse based on an evaluation index of a decoding result, which is a result of decoding a reproduction signal of the encoded data, for each of the classification; and generating the recording pulse corresponding to the encoded data by using the correction amount corresponding to the classification of the run length of the encoded data.