Provided is a magnetic tape, in which, in an environment of a temperature of 32 C. and a relative humidity of 80%, a frictional force F.sub.45 on a magnetic layer surface with respect to an LTO8 head measured at a head tilt angle of 45 is 4 gf or more and 15 gf or less, and standard deviation of a frictional force F on the magnetic layer surface with respect to the LTO8 head respectively measured at head tilt angles of 0, 15, 30, and 45 is 10 gf or less. The magnetic tape includes a polyethylene naphthalate support having a Young's modulus in a width direction of 10000 MPa or more.

A magnetic recording medium is a tape-shaped magnetic recording medium, including: a substrate; an underlayer provided on the substrate; and a magnetic layer provided on the underlayer. The substrate contains polyester, each of the underlayer and the magnetic layer contains a lubricant, the magnetic layer has a surface on which a large number of holes is provided, the arithmetic average roughness Ra of the surface is 2.5 nm or less, a BET specific surface area of the entire magnetic recording medium measured in a state where the magnetic recording medium has been washed and dried is 3.5 m.sup.2/g or more and 7.0 m.sup.2/g or less, a squareness ratio of the magnetic layer in a vertical direction is 65% or more, an average thickness of the magnetic layer is 80 nm or less, an average thickness of the magnetic recording medium is 5.6 m or less, and a servo pattern is recorded on the magnetic layer and a statistical value .sub.SW indicating a non-linearity of the servo pattern is 24 nm or less.

An apparatus according to one embodiment includes a module having an array of first read transducers each having a tunnel valve structure and a second read transducer coupled to the array of first read transducers, the second read transducer having a tunnel valve structure. The apparatus also includes a controller, and a cable coupling the read transducers to the controller, thereby forming a plurality of circuits extending from the controller, each circuit corresponding to one of the transducers. Resistances of the circuits are about the same.

An apparatus according to one embodiment includes a first read transducer having a tunnel valve structure, and a second read transducer coupled to the first read transducer. The second read transducer has a tunnel valve structure as well, but the tunnel valve structure of the first read transducer has a different resistivity than the tunnel valve structure of the second read transducer. An apparatus according to another embodiment includes an array of first read transducers, each first read transducer having a tunnel valve structure. At least a second read transducer is coupled to the first read transducers, the second read transducer having a tunnel valve structure. The tunnel valve structure of the first read transducer has a different resistivity than the tunnel valve structure of the second read transducer.

A magnetic head includes a first servo reading element pair, a second servo reading element pair, and a plurality of magnetic elements. The first servo reading element pair consists of a first servo reading element and a second servo reading element, the second servo reading element pair consists of a third servo reading element and a fourth servo reading element, the first servo reading element and the third servo reading element are disposed on one end side of the plurality of magnetic elements and read one servo band of the pair of servo bands, and the second servo reading element and the fourth servo reading element are disposed on the other end side of the plurality of magnetic elements and read the other servo band of the pair of servo bands.

The magnetic tape includes a non-magnetic support, and a magnetic layer containing a ferromagnetic powder. A magnetic tape cartridge and a magnetic tape apparatus include the magnetic tape. A dale void volume Vvv specified in ISO 25178 on a surface of the magnetic layer is 0.100 nm.sup.3 or more and 0.350 nm.sup.3 or less, and standard deviation a of the Vvv in a width direction of the surface of the magnetic layer is 0.020 nm.sup.3 or less.

The magnetic tape includes a non-magnetic support, and a magnetic layer containing a ferromagnetic powder. A magnetic tape cartridge and a magnetic tape apparatus include the magnetic tape. Sci obtained by measuring a surface of the magnetic layer with an atomic force microscope and by Equation A is 1.40 or more and 1.60 or less, and standard deviation of the Sci in a width direction of the surface of the magnetic layer is 0.05 or less. In Equation A, Sq is a root-mean-square height Sq specified in ISO 25178, Vv(h.sub.0.05)-Vv(h.sub.0.8) is a void volume in a region where a load area ratio in a bearing curve is 5% or more and 80% or less, and A is a measurement region area.

[00001]$\begin{array}{cc}\mathrm{Sci}=\left(\frac{\mathrm{Vv}\left(h_{0.05}\right)-\mathrm{Vv}\left(h_{0.8}\right)}{A}\right)/\mathrm{Sq}& \mathrm{Equation}A\end{array}$

A servo writer includes a running unit that sends a tape-like magnetic recording medium out from a cartridge, winds up the sent out magnetic recording medium, and runs the magnetic recording medium; an erasing unit that erases a first servo pattern formed in the magnetic recording medium that runs; a head that writes a servo signal in the running magnetic recording medium from which the first servo pattern is erased and forms a second servo pattern; and a control unit that controls the head so that the servo signal is written in at least one period of an accelerated running period and a decelerated running period of the magnetic recording medium, and forms the second servo pattern that does not satisfy a standard in the magnetic recording medium.

A first servo pattern has a first position and a second position which intersect an imaginary line. A second servo pattern has a third position intersecting the imaginary line. The imaginary line is set at a position at which a relationship in which a distance between the first position and the second position is half of a distance between the first position and the third position is established between the first servo pattern and the second servo pattern adjacent to each other in a longitudinal direction. A width of a servo band is set to a length in which a distance from the imaginary line to one end of the servo band in a width direction and a distance from the imaginary line to the other end of the servo band in the width direction are equal.

A method for writing a servo pattern to a magnetic tape medium includes orienting a magnetic flux in opposite directions across gaps in the magnetic tape medium, and moving the magnetic tape medium with its servo band above two gaps in a direction along a longitudinal extension of the magnetic tape medium. The magnetic tape medium includes a servo band along the longitudinal extension of the magnetic tape medium and a servo pattern organized in a servo frame with a first burst having at least two servo stripes, and a second burst having at least two servo stripes. For at least one of the first and second bursts, different stripes within a same burst have opposite magnetic polarities with respect to one another. The method further includes applying a current pulse to the coil, moving the magnetic tape medium, and applying another current pulse to the coil.