A magnetic tape including a timing-based servo pattern, in which the magnetic tape is used in a magnetic tape device in which a total number of data tracks is 8705 or more in conversion of a magnetic tape having a width of ½ inches, and ΔPNL of the timing-based servo pattern is 10.0% or less of a track pitch. A magnetic tape cartridge including the magnetic tape, and a magnetic tape device including a magnetic tape, in which a total number of data tracks is 8705 or more in conversion of a magnetic tape having a width of ½ inches, the magnetic tape includes a timing-based servo pattern, and ΔPNL of the timing-based servo pattern is 10.0% or less of a track pitch are provided. The ΔPNL indicates an amount of deviation of the timing-based servo pattern from linearity.

A magnetic tape including a timing-based servo pattern, in which the magnetic tape is used in a magnetic tape device in which a total number of data tracks is 8705 or more in conversion of a magnetic tape having a width of ½ inches, and ΔPNL of the timing-based servo pattern is 10.0% or less of a track pitch. A magnetic tape cartridge including the magnetic tape, and a magnetic tape device including a magnetic tape, in which a total number of data tracks is 8705 or more in conversion of a magnetic tape having a width of ½ inches, the magnetic tape includes a timing-based servo pattern, and ΔPNL of the timing-based servo pattern is 10.0% or less of a track pitch are provided. The ΔPNL indicates an amount of deviation of the timing-based servo pattern from linearity.

The magnetic tape includes a non-magnetic support; and a magnetic layer including a ferromagnetic powder and a binding agent on the non-magnetic support, in which the magnetic layer has a timing-based servo pattern, a center line average surface roughness Ra measured regarding a surface of the magnetic layer is equal to or smaller than 1.8 nm, and an isoelectric point of a surface zeta potential of the magnetic layer is equal to or greater than 5.5.

The magnetic tape includes a non-magnetic support; and a magnetic layer including a ferromagnetic powder and a binding agent on the non-magnetic support, in which the magnetic layer has a timing-based servo pattern, a center line average surface roughness Ra measured regarding a surface of the magnetic layer is equal to or smaller than 1.8 nm, and an isoelectric point of a surface zeta potential of the magnetic layer is equal to or greater than 5.5.

A method for writing servo information in a disk drive that includes a write head and one or more recording surfaces includes: writing a first portion of a first spiral with the write head on a first recording surface of the one or more recording surfaces while controlling a radial position of the write head with a controller that is configured with a first set of controller parameter values; after the read head crosses a second spiral formed on a second recording surface of the one or more recording surfaces, determining a radial position error for the write head based on information associated with the second spiral; and in response to the radial position error exceeding a disturbance threshold value, writing a second portion of the first spiral with the write head while controlling the radial position of the write head with the controller while the controller is configured with a second set of controller parameter values.

A method for writing servo information in a disk drive that includes a write head and one or more recording surfaces includes: writing a first portion of a first spiral with the write head on a first recording surface of the one or more recording surfaces while controlling a radial position of the write head with a controller that is configured with a first set of controller parameter values; after the read head crosses a second spiral formed on a second recording surface of the one or more recording surfaces, determining a radial position error for the write head based on information associated with the second spiral; and in response to the radial position error exceeding a disturbance threshold value, writing a second portion of the first spiral with the write head while controlling the radial position of the write head with the controller while the controller is configured with a second set of controller parameter values.

A first straight line region and a second straight line region of the straight line region pair are inclined in opposite directions with respect to a first imaginary straight line. The first straight line region has a steeper inclined angle with respect to the first imaginary straight line than the second straight line region. Positions of both ends of the first straight line region and positions of both ends of the second straight line region are aligned in a direction corresponding to a width direction of a magnetic tape. A plurality of gap patterns deviate from each other by a predetermined interval in a direction corresponding to a longitudinal direction of the magnetic tape, between the gap patterns adjacent to each other along the direction corresponding to the width direction of the magnetic tape. A substrate is inclined with respect to the first imaginary straight line.

A first straight line region and a second straight line region of the straight line region pair are inclined in opposite directions with respect to a first imaginary straight line. The first straight line region has a steeper inclined angle with respect to the first imaginary straight line than the second straight line region. Positions of both ends of the first straight line region and positions of both ends of the second straight line region are aligned in a direction corresponding to a width direction of a magnetic tape. A plurality of gap patterns deviate from each other by a predetermined interval in a direction corresponding to a longitudinal direction of the magnetic tape, between the gap patterns adjacent to each other along the direction corresponding to the width direction of the magnetic tape. A substrate is inclined with respect to the first imaginary straight line.

A magnetic disk device includes a disk, first and second heads, a motor, and a controller. The disk includes a first surface and a second surface opposite to the first surface. The first head is configured to perform reading and writing with respect to the first surface. The second head is configured to perform reading and writing with respect to the second surface. The motor is configured to move the first and second heads with respect to the first and second surfaces, respectively, along a radial direction of the disk. The controller is configured to alternately activate the first and second heads to perform writing of a plurality of spiral patterns on the first and second surfaces of the disk, respectively, while controlling the motor to move the first and second heads at a predetermined constant speed with respect to the first and second surfaces in the radial direction.

A magnetic disk device includes a disk, first and second heads, a motor, and a controller. The disk includes a first surface and a second surface opposite to the first surface. The first head is configured to perform reading and writing with respect to the first surface. The second head is configured to perform reading and writing with respect to the second surface. The motor is configured to move the first and second heads with respect to the first and second surfaces, respectively, along a radial direction of the disk. The controller is configured to alternately activate the first and second heads to perform writing of a plurality of spiral patterns on the first and second surfaces of the disk, respectively, while controlling the motor to move the first and second heads at a predetermined constant speed with respect to the first and second surfaces in the radial direction.