A magnetic tape device, in which a magnetic tape is caused to run between a winding reel and a cartridge reel in a state where a tension is applied in a longitudinal direction of the magnetic tape and a maximum value of the tension is 0.50 N or more, and the magnetic tape after running in a state where the tension is applied is caused to be wound around the cartridge reel by applying a tension of 0.40 N or less in the longitudinal direction of the magnetic tape, and a curvature of the magnetic tape in the longitudinal direction is 4 mm/m or less.

A magnetic tape device, in which a magnetic tape is caused to run between a winding reel and a cartridge reel in a state where a tension is applied in a longitudinal direction of the magnetic tape and a maximum value of the tension is 0.50 N or more, and the magnetic tape after running in a state where the tension is applied is caused to be wound around the cartridge reel by applying a tension of 0.40 N or less in the longitudinal direction of the magnetic tape, and an edge weave amount of a tape edge on at least one side of the magnetic tape is 1.5 μm or less.

The magnetic tape cartridge includes a magnetic tape, and a cartridge reel, in which, in the magnetic tape, a minimum winding deviation occurrence load measured after the magnetic tape is rewound around the cartridge reel by applying a tension of 0.20 N in a longitudinal direction of the magnetic tape is 200 N or less.

Provided are a magnetic tape comprising a magnetic layer containing a ferromagnetic powder and a binding agent on a non-magnetic support, in which the magnetic layer contains an oxide abrasive, an average particle diameter of the oxide abrasive obtained from a secondary ion image acquired by irradiating a surface of the magnetic layer with a focused ion beam is 0.04 μm to 0.08 μm, and an absolute value ΔN of a difference between a refractive index Nxy measured with respect to an in-plane direction of the magnetic layer and a refractive index Nz measured with respect to a thickness direction of the magnetic layer is 0.25 to 0.40, and a magnetic recording and reproducing device including the magnetic tape.

An information processing device includes a generation unit that generates a hierarchy of a group that classifies each piece of data from information about each of a plurality of pieces of data to be recorded, and a control unit that controls recording of the plurality of pieces of data included in a group of the hierarchy at a highest level on a magnetic recording medium in a recording order according to an order from an upper hierarchy to a lower hierarchy, for each group of the hierarchy at the highest level. The magnetic recording medium has a magnetic layer containing a ferromagnetic powder and a binding agent on a non-magnetic support. A difference between spacings S.sub.0.5 and S.sub.13.5 measured under pressures of 0.5 atm and 13.5 atm by an optical interference method after n-hexane cleaning on a surface of the magnetic layer is equal to or less than 3.0 nm.

An information processing device includes a generation unit that generates a hierarchy of a group that classifies each piece of data from information about each of a plurality of pieces of data to be recorded, and a control unit that controls recording of the plurality of pieces of data included in a group of the hierarchy at a highest level on a magnetic recording medium in a recording order according to an order from an upper hierarchy to a lower hierarchy, for each group of the hierarchy at the highest level. The magnetic recording medium has a magnetic layer containing a ferromagnetic powder and a binding agent on a non-magnetic support. A difference between spacings S.sub.0.5 and S.sub.13.5 measured under pressures of 0.5 atm and 13.5 atm by an optical interference method after n-hexane cleaning on a surface of the magnetic layer is equal to or less than 3.0 nm.

The magnetic recording medium includes: a non-magnetic support; and a magnetic layer including ferromagnetic powder, in which a difference S.sub.after−S.sub.before between a spacing S.sub.after measured on a surface of the magnetic layer by optical interferometry after methyl-ethyl-ketone cleaning and a spacing S.sub.before measured on the surface of the magnetic layer by optical interferometry before methyl-ethyl-ketone cleaning is more than 0 nm and 15.0 nm or less, and the non-magnetic support is an aromatic polyamide support having a moisture absorption of 2.2% or less.

The magnetic tape includes a non-magnetic support; and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support, in which an absolute value ΔN of a difference between a refractive index Nxy measured regarding an in-plane direction of the magnetic layer and a refractive index Nz measured regarding a thickness direction of the magnetic layer is 0.25 to 0.40, and a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding a surface of the magnetic layer is equal to or smaller than 0.050.

The magnetic tape includes a non-magnetic support; and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support, in which an absolute value ΔN of a difference between a refractive index Nxy measured regarding an in-plane direction of the magnetic layer and a refractive index Nz measured regarding a thickness direction of the magnetic layer is 0.25 to 0.40, and a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding a surface of the magnetic layer is equal to or smaller than 0.050.

The magnetic tape includes a non-magnetic support; and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support, in which the magnetic layer includes one or more components selected from the group consisting of fatty acid and fatty acid amide, a C—H derived C concentration calculated from a C—H peak area ratio of C1s spectra obtained by X-ray photoelectron spectroscopic analysis performed on a surface of the magnetic layer at a photoelectron take-off angle of 10 degrees is equal to or greater than 45 atom %, and an absolute value ΔN of a difference between a refractive index Nxy measured regarding an in-plane direction of the magnetic layer and a refractive index Nz measured regarding a thickness direction of the magnetic layer is 0.25 to 0.40.