First and second tracks are read simultaneously via a first reader mounted in a head-gimbal assembly. The first reader provides a first signal based on detecting a total perpendicular field of the first and second tracks. The first and second tracks are read simultaneously via a second reader mounted in the head-gimbal assembly. The second reader provides a second signal based on detecting a total longitudinal field of the first and second tracks. At least one of a position error and a timing error of at least one of the first and second readers are determined based on user data read via the respective first and second signals.

A recording head has a first magnetic writer and a second magnetic writer offset from the first magnetic writer in a downtrack and crosstrack direction. The recording head has leads configured to deliver respective first and second write and/or laser currents to the first and second writers. The first and second write and/or laser currents enable the first and second writers to simultaneously write to adjacent tracks of a magnetic disk.

A disk apparatus includes recording disks and a first and a second actuator assembly that rotate about a support shaft and that each include: an actuator block; a wiring board having connection terminals and installed on an installation surface of the actuator block; and head assemblies each attached to the actuator block via an arm and each including a head and an interconnection member. The wiring board of each of the first and the second actuator assembly has a connection portion connected to one of the connection terminals and located adjacently to a boundary between the first and the second actuator assembly, and the connection portion of the first or the second actuator assembly is bent with respect to the installation surface.

A method and system provide a storage device. A plurality of read sensor stacks for each reader of the storage device are provided. The read sensor stacks are distributed along a down track direction and offset in a cross-track direction. A plurality of electronic lapping guides (ELGs) are provided for the read sensor stacks. The read sensor stacks are lapped. Lapping is terminated based on signal(s) from the ELG(s).

An exemplary data refresh method disclosed herein reading data into volatile memory from a first storage region using a read element controlled by a first actuator assembly and writing the data from the volatile memory to a second storage region using a write element controlled by a second actuator assembly, where the first actuator assembly and the second actuator assembly are configured to receive data from control circuitry via independent read/write communication channels.

A disk apparatus includes recording disks and a first and a second actuator assembly that rotate about a support shaft and that each include: an actuator block; a wiring board having connection terminals and installed on an installation surface of the actuator block; and head assemblies each attached to the actuator block via an arm and each including a head and an interconnection member. The wiring board of each of the first and the second actuator assembly has a connection portion connected to one of the connection terminals and located adjacently to a boundary between the first and the second actuator assembly, and the connection portion of the first or the second actuator assembly is bent with respect to the installation surface.

A magnetic disk device includes a magnetic head that writes data on and reads data from the magnetic disk, and a controller circuit. The controller circuit is configured to control a gap between the magnetic head and the magnetic disk, and select one of two or more gap values for the fly height, based on a write location in the magnetic disk of data to be written by the magnetic head.

According to one embodiment, a data processor includes an interface section and a processor. The interface section is configured to acquire partial data relating to a control condition of a magnetic recording/reproducing device. The processor is configured to process the partial data. The processor is configured to derive a first data by processing the partial data with a first model based on characteristics of the partial data, a first resolution of the first data being higher than a partial resolution of the partial data. The processor is configured to derive a second data by processing the partial data with a second model based on the characteristic. The second model is different from the first model. A second resolution of the second data being higher than the partial resolution.

A signal is monitored that provides an indicator of disturbance affecting a hard disk drive. In response to determining that the indicator of the disturbance satisfies a threshold, a lattice recursive least squares computation is applied to the signal to determine at least one notch frequency. A notch filter is formed using the at least one notch frequency. The notch filter is used by a servo controller loop that positions a read/write head over a disk of the hard disk drive. The notch filter is applied to the servo control loop for subsequent positioning of the read/write head.

A method of forming a recording head for use with a data storage medium in a data storage device. The method includes forming first and second writers of different target geometries. A first recording measurement is performed on one or more storage media using the first writer. A second recording measurement is performed on the one or more storage media using the second writer. Based on a comparison of the first and second recording measurements to a predetermined quantity, either the first writer or the second writer is selected to be operational in the data storage device.