In the magnetic tape, in a case where a maximum value of an absolute value of a difference between a servo band spacing obtained before storage, and a servo band spacing obtained after storage of N cycles, in a case where predetermined storage is set to one cycle, is defined as A, a medium life calculated by a linear function that is derived from the value of A and the value of the logarithm log.sub.eT of total storage time T of the storage of N cycles is 3 years or longer. The medium life is T in a case where the A satisfies Equation a: A=1.5−B. The B is calculated by multiplying a difference between a maximum value and a minimum value of the servo band spacings obtained in each of the five environments by ½.

In the magnetic tape, in a case where a maximum value of an absolute value of a difference between a servo band spacing obtained before storage, and a servo band spacing obtained after storage of N cycles, in a case where predetermined storage is set to one cycle, is defined as A, a medium life calculated by a linear function that is derived from the value of A and the value of the logarithm log.sub.eT of total storage time T of the storage of N cycles is 3 years or longer. The medium life is T in a case where the A satisfies Equation a: A=1.5−B. The B is calculated by multiplying a difference between a maximum value and a minimum value of the servo band spacings obtained in each of the five environments by ½.

A magnetic recording medium that can exhibit good traveling performance during use is provided. This magnetic recording medium is a tape-shaped magnetic recording medium, and includes a substrate, a base layer disposed on the substrate, and a magnetic layer disposed on the base layer. The substrate includes a polyester as a main component. The average thickness of the base layer is 0.9 μm or less. The base layer and the magnetic layer each include a lubricant. The magnetic layer has a surface having a large number of holes, and the arithmetic average roughness Ra of the surface is 2.5 nm or less. The BET specific surface area of the entire magnetic recording medium is 3.5 m.sup.2/g or more in a state where the lubricant has been removed from the magnetic recording medium and the magnetic recording medium has been dried. The squareness ratio in the perpendicular direction is 65% or more. The average thickness of the magnetic layer is 90 nm or less. The average thickness of the magnetic recording medium is 5.6 μm or less.

A magnetic recording medium that can exhibit good traveling performance during use is provided. This magnetic recording medium is a tape-shaped magnetic recording medium, and includes a substrate, a base layer disposed on the substrate, and a magnetic layer disposed on the base layer. The substrate includes a polyester as a main component. The average thickness of the base layer is 0.9 μm or less. The base layer and the magnetic layer each include a lubricant. The magnetic layer has a surface having a large number of holes, and the arithmetic average roughness Ra of the surface is 2.5 nm or less. The BET specific surface area of the entire magnetic recording medium is 3.5 m.sup.2/g or more in a state where the lubricant has been removed from the magnetic recording medium and the magnetic recording medium has been dried. The squareness ratio in the perpendicular direction is 65% or more. The average thickness of the magnetic layer is 90 nm or less. The average thickness of the magnetic recording medium is 5.6 μm or less.

A magnetic recording head includes a write pole including an end proximal to a media-facing surface of the magnetic recording head, a return pole disposed a distance from the write pole in a down-track dimension of the magnetic recording head, and a writer coil configured to produce a magnetic flux in the write pole. The writer coil includes a first segment and a second segment. The first segment is disposed proximal to the end of the write pole and between the write pole and the return pole. The second segment is electrically coupled to the first segment. A thickness of the second segment in the down-track dimension is greater than a thickness of the first segment in the down-track dimension.

A magnetic recording head includes a write pole including an end proximal to a media-facing surface of the magnetic recording head, a return pole disposed a distance from the write pole in a down-track dimension of the magnetic recording head, and a writer coil configured to produce a magnetic flux in the write pole. The writer coil includes a first segment and a second segment. The first segment is disposed proximal to the end of the write pole and between the write pole and the return pole. The second segment is electrically coupled to the first segment. A thickness of the second segment in the down-track dimension is greater than a thickness of the first segment in the down-track dimension.

Provided are a magnetic tape control system that executes pre-rewinding storage of storing a magnetic tape in a state of being wound around a reel, and post-rewinding storage of storing the magnetic tape in a state of being rewound around a reel different from or the same reel as the reel after the pre-rewinding storage such that an end that is a tape outside end during the pre-rewinding storage is turned into a tape inside end and an end that is a tape inside end during the pre-rewinding storage is turned into a tape outside end, and a magnetic tape control device including a rewinding control unit that transmits rewinding execution information, and a drive unit that receives the rewinding execution information and starts running of a magnetic tape stored in a state of being wound around a reel to execute rewinding of the magnetic tape.

Provided are a magnetic tape control system that executes pre-rewinding storage of storing a magnetic tape in a state of being wound around a reel, and post-rewinding storage of storing the magnetic tape in a state of being rewound around a reel different from or the same reel as the reel after the pre-rewinding storage such that an end that is a tape outside end during the pre-rewinding storage is turned into a tape inside end and an end that is a tape inside end during the pre-rewinding storage is turned into a tape outside end, and a magnetic tape control device including a rewinding control unit that transmits rewinding execution information, and a drive unit that receives the rewinding execution information and starts running of a magnetic tape stored in a state of being wound around a reel to execute rewinding of the magnetic tape.

A PMR writer with a capacitive one turn design is disclosed with a one turn top coil above the main pole (MP), a one turn bottom coil below the MP, and where a capacitor (C_bot) is electrically connected to the bottom coil thereby shunting the write current (lw) in the bottom coil above certain frequencies proximate to 1 GHz. The C_bot is made of TiO.sub.2 or Al-doped TiO.sub.2, for example, with a dielectric constant >10. As a result, the writer behaves like a 1+1T writer at lw frequencies substantially below 1 GHz, as a 1+0.xT writer at lw frequencies proximate to 1 GHz, and like a 1+0T writer in an overshoot region of the lw. Accordingly, better trailing shield field gradient, signal-to-noise ratio, and bit error rate during high frequency operation are achieved without compromising saturation speed and adjacent track interference for an overall improvement in performance.

A data writer may be constructed and operated as part of a data storage device. The data writer can be positioned proximal a data storage medium. The data writer may have a write pole positioned adjacent a writer coil with the writer coil having a plurality of turns. A controller that is connected to each turn can be adapted to selectively activate less than all the coil turns in response to the data writer being positioned over a first portion of a data storage medium and selectively activate all of the coil turns in response to the data writer being positioned over a second portion of the data storage medium.