A method for manufacturing a ring-shaped glass spacer to be arranged in contact with a magnetic disk in a hard disk drive device includes processing for forming a film on the surface of a glass spacer main body, which is the base of the glass spacer. In the processing, the film is formed by passing the glass spacer main body through a location where the components of the film are in a spray state while an outer circumferential edge surface of the glass spacer main body is being rotated in a circumferential direction thereof.

A cartridge is provided and includes tape-shaped magnetic recording medium; and cartridge memory; wherein cartridge memory includes communication unit that communicates with recording/reproducing device in state where cartridge is loaded on recording/reproducing device; storage unit; and control unit that stores, reads, and transmits information, wherein information includes manufacturing information of cartridge and adjustment information for adjusting a tension applied to the tape-shaped magnetic recording medium in a longitudinal direction of tape-shaped magnetic recording medium thereof, tape-shaped magnetic recording medium has a plurality of servo bands, and wherein a temperature expansion coefficient α of the tape-shaped magnetic recording medium satisfies 6 ppm/° C.≤α≤8 ppm/° C.

A disk for a magnetic recording apparatus is described. The disk includes a first surface extending along a first plane, a second surface extending along a second plane parallel to the first plane, and a disk thickness between the first surface and the second surface, measured along a first direction substantially normal to the first surface. The disk further includes an edge surface disposed along a perimeter of the disk and between the first surface and the second surface, where the edge surface extends along a third plane substantially perpendicular to the first surface, a first chamfer disposed between the first surface and the edge surface, and a second chamfer disposed between the second surface and the edge surface. In an aspect, a length of the edge surface measured along the first direction may be between 40% and 80% of the disk thickness.

A disk for a magnetic recording apparatus is described. The disk includes a first surface extending along a first plane, a second surface extending along a second plane parallel to the first plane, and a disk thickness between the first surface and the second surface, measured along a first direction substantially normal to the first surface. The disk further includes an edge surface disposed along a perimeter of the disk and between the first surface and the second surface, where the edge surface extends along a third plane substantially perpendicular to the first surface, a first chamfer disposed between the first surface and the edge surface, and a second chamfer disposed between the second surface and the edge surface. In an aspect, a length of the edge surface measured along the first direction may be between 40% and 80% of the disk thickness.

Provided is a glass for a magnetic recording medium substrate, which is an amorphous glass, in which an SiO.sub.2 content is in a range of 54 mol % or more and 62 mol % or less, an MgO content is in a range of 15 mol % or more and 28 mol % or less, an Li.sub.2O content is in a range of 0.2 mol % or more, and an Na.sub.2O content is in a range of 5 mol % or less.

The present disclosure provides systems and methods associated with data storage using atomic films, such as graphene, boron nitride, or silicene. A platter assembly may include at least one platter that has one or more substantially planar surfaces. One or more layers of a monolayer atomic film, such as graphene, may be positioned on a planar surface. Data may be stored on the atomic film using one or more vacancies, dopants, defects, and/or functionalized groups (presence or lack thereof) to represent one of a plurality of states in a multi-state data representation model, such as a binary, a ternary, or another base N data storage model. A read module may detect the vacancies, dopants, and/or functionalized groups (or a topographical feature resulting therefrom) to read the data stored on the atomic film.

A non-metallic media substrate includes a disc-shaped substrate body having at least one media storage surface on a face thereof. The substrate body has a center opening having an inner diameter and an outer diameter surface, and the substrate body has a thickness. The substrate further includes an annular groove at the outer diameter of the media substrate, the annular groove having chamfered edges and an internal concavity extending toward the inner diameter.

A magnetic tape cartridge includes a case on which an identifier is displayed, and a storage medium in which reading condition information that is information regarding a condition for reading the identifier is stored.

Provided is a glass for a magnetic recording medium substrate, which is an amorphous glass, in which an SiO.sub.2 content is in a range of 54 mol % or more and 62 mol % or less, an MgO content is in a range of 15 mol % or more and 28 mol % or less, an Li.sub.2O content is in a range of 0.2 mol % or more, and an Na.sub.2O content is in a range of 5 mol % or less.

A method in one embodiment includes fabricating a tape having an applicator portion for applying an organic coating to a magnetic head for reducing exposure of the head to oxidation promoting materials. The method also includes applying the organic coating to the applicator portion of the tape, the organic coating being for coating a tape bearing surface of the magnetic head with the organic coating upon the applicator portion being run over the tape bearing surface of the magnetic head. The method further includes applying a lubricant to a data portion of the tape.