A computer-implemented method, according to one embodiment, includes: determining, by the computer, whether a difference between information and corresponding design values is in a range. The information corresponds to how an array of writers write and/or are expected to write to a magnetic medium during shingled recording. Moreover, the computer-implemented method further includes: computing, by the computer and using the information, data describing a lateral writing position to use during writing such that shingled track edges are aligned according to a format in response to determining that the difference between the information and corresponding design values is not in the range.

A storage device includes read circuitry having a read head having a detector that outputs signals representing data from a first track and an adjacent track. The read head is subject to off-track excursions during which the read head detects signals from both the first track and an adjacent track. Data on each track includes a preamble including a repeating pattern. The repeating pattern in any first track is orthogonal to the repeating pattern in any track adjacent to the first track. The read circuitry also includes respective Discrete Fourier Transform circuits to identify components in the signals corresponding to respective frequencies characteristic of the repeating pattern on the first track and the repeating pattern on the second track, and computation circuitry to determine from the components a ratio by which the read head is off-track. Corresponding methods are provided for operating such a storage device and for reading data.

Mounting a data storage medium having information recorded thereon, where: the information is formatted according to a data storage format standard that includes first write and read functions, the information includes first and second datasets, the first dataset includes a first file mark, an index, and an empty space between the second dataset and a combination of the first file mark and the index; receiving, from a first application, a data block and a write command for writing the data block onto the data storage medium; and in response to receiving the write command: determining that the empty space is present in the first dataset, writing, by a second write function, the data block into the empty space, and writing a second file mark in the second dataset; wherein the empty space of the data storage medium is inaccessible to the first write function of the data storage format standard.

According to one embodiment, a magnetic disk apparatus includes a magnetic disk, a magnetic head, and a controller. The magnetic disk is provided with a track including a plurality of first sectors. The controller accesses the magnetic disk by using the magnetic head. The plurality of first sectors includes a plurality of second sectors where data segments are written and a third sector where parity and first information indicating effectiveness or ineffectiveness of protection by the parity are written.

A servo pattern recording method includes: determining a first servo band group that includes three or more servo bands for recording a servo pattern in which first servo band identification information having a plurality of bits is to be embedded, and a second servo band group that includes three or more servo bands for recording a servo pattern in which second servo band identification information having a plurality of bits is to be embedded, the second servo band identification information being different from the first servo band identification information; and recording the first and second servo band identification information on the first and second servo band groups, respectively, such that a combination of a first pair and a second pair is not duplicated, the first pair being a pair of servo band identification information and a phase in one servo band read by a first servo read head, the second pair being a pair of servo band identification information and a phase in the other servo band read by a second servo read head.

A method includes receiving a write request to write a current data block to a Shingled Magnetic Recording (SMR) storage device. In response, the current data block is written to a current physical block in an open zone of the SMR storage device. A corresponding copy of the current data block is written to a nonvolatile memory. A determination is made of whether a wandering write error occurred during the writing of the data to the open zone. In response to the wandering write error occurring, for each of the number of written physical blocks in the open zone that have the corresponding copy in the nonvolatile memory, the data in the physical block is validated using the corresponding copy. In response to validation, the data in the corresponding copy is written as corrected data for the physical block to a new zone in the SMR storage device.

In a multilayer optical disc having information layers conforming to a plurality of different optical disc standards, because the type of each information layer is not recorded in the other information layers, in read and write operations by a compatible optical disc device conforming to a plurality of optical disc standards, every time the information layer being accessed changes, it has been necessary to read the type of the information layer and select a method of generating a tracking error signal adapted to the type of information layer, so access has taken time. In order to solve the above problem, in the optical multilayer disc according to the present invention, having information layers conforming to a plurality of different optical disc standards, in an area in one of the information layers, information about the other information layers is recorded. The time required to access the other information layers can be reduced by using this information to select a tracking error signal generating method.

A method is disclosed that includes: receiving, via a network digital video recorder, a request to record requested content; receiving, via a network digital video recorder at a first time, the requested content in a first format and the requested content in a second format; storing, via the network digital video recorder, the requested content in the first format; storing, via the network digital video recorder, the requested content in the second format; deleting, from network digital video recorder, the requested content in the second format after a predetermined time period; and transcoding, via an on demand transcoder, the requested content in the first format to the requested content in a third format after the predetermined time period.

A write command is received to write data in a Conventional Magnetic Recording (CMR) realm of a disk to be formatted for writing data in non-overlapping tracks. The disk includes a plurality of areas of the disk that can be formatted as a CMR realm or as a Shingled Magnetic Recording (SMR) realm formatted for writing data in overlapping tracks. It is determined whether performance of the write command would require writing to begin in a portion of the CMR realm that has not been written with non-overlapping tracks. In response to determining that the performance of the write command would require writing to begin in a portion of the CMR realm that has not been written with non-overlapping tracks, a predefined data pattern is written using non-overlapping tracks in the portion of the CMR realm that has not been written with non-overlapping tracks.

A write command is received to write data in a Conventional Magnetic Recording (CMR) realm of a disk to be formatted for writing data in non-overlapping tracks. The disk includes a plurality of areas of the disk that can be formatted as a CMR realm or as a Shingled Magnetic Recording (SMR) realm formatted for writing data in overlapping tracks. It is determined whether performance of the write command would require writing to begin in a portion of the CMR realm that has not been written with non-overlapping tracks. In response to determining that the performance of the write command would require writing to begin in a portion of the CMR realm that has not been written with non-overlapping tracks, a predefined data pattern is written using non-overlapping tracks in the portion of the CMR realm that has not been written with non-overlapping tracks.