In order to suppress the occurrence of adhesion between magnetic disks and spacers when the magnetic disks and the spacers are removed from a hard disk drive apparatus in which the magnetic disks and the spacers are installed, a surface roughness Ra of a main surface of a ring-shaped glass spacer to be arranged in contact with a magnetic disk is set to be not larger than 1.0 μm, and an average inclination RΔa of the main surface is set to be at least 0.02.

An apparatus includes one or more disc media cassettes configured to store multiple disc-based media. Multiple disc drives are configured to read and write data to the multiple disc-based media. A robotic delivery device is configured to transport a selected disc-based media to and from at least one disc drive of the multiple disc drives, and to transport the selected disc-based media directly to a spindle on the at least one disc drive.

A ring-shaped spacer is to be arranged in contact with a magnetic disk in a hard disk drive apparatus. A maximum height surface roughness Rz of an outer circumferential edge surface of the spacer is at least 1.5 μm, and the spacer is made of amorphous glass.

A ring-shaped spacer is to be arranged in contact with a magnetic disk in a hard disk drive apparatus. A maximum height surface roughness Rz of an outer circumferential edge surface of the spacer is at least 1.5 μm, and the spacer is made of amorphous glass.

Aspects of the disclosure provide for mitigating a coefficient of thermal expansion (CTE) mismatch between glass components and adjacent metal components in a disk storage device to improve thermal and shock performance. The methods and apparatus provide a hub, provide a first recording disk comprising a glass material and a center hole on the hub such that the hub extends through the center hole of the first recording disk, provide a first spacer on the first recording disk, the first spacer comprising a nickel-iron alloy, and provide a second recording disk comprising a glass material and a center hole on the first spacer such that the hub extends through the center hole of the second recording disk, wherein the first recording disk and the second recording disk each comprise a magnetic recording layer configured to store information.

A method for manufacturing the ring-shaped glass spacer to be arranged in contact with a magnetic disk in a hard disk drive apparatus, including: preparing a ring-shaped glass blank; and grinding main surfaces of the ring-shaped glass blank by using grinding pads that include diamond particles as fixed abrasive particles.

A method for manufacturing the ring-shaped glass spacer to be arranged in contact with a magnetic disk in a hard disk drive apparatus, including: preparing a ring-shaped glass blank; and grinding main surfaces of the ring-shaped glass blank by using grinding pads that include diamond particles as fixed abrasive particles.

Aspects of the disclosure provide for mitigating a coefficient of thermal expansion (CTE) mismatch between glass components and adjacent metal components in a disk storage device to improve thermal and shock performance. The methods and apparatus provide a hub, provide a first recording disk comprising a glass material and a center hole on the hub such that the hub extends through the center hole of the first recording disk, provide a first spacer on the first recording disk, the first spacer comprising a nickel-iron alloy, and provide a second recording disk comprising a glass material and a center hole on the first spacer such that the hub extends through the center hole of the second recording disk, wherein the first recording disk and the second recording disk each comprise a magnetic recording layer configured to store information.

Aspects of the disclosure provide for mitigating a coefficient of thermal expansion (CTE) mismatch between glass components and adjacent metal components in a disk storage device to improve thermal and shock performance. The methods and apparatus provide a hub, provide a first recording disk comprising a glass material and a center hole on the hub such that the hub extends through the center hole of the first recording disk, provide a first spacer on the first recording disk, the first spacer comprising a nickel-iron alloy, and provide a second recording disk comprising a glass material and a center hole on the first spacer such that the hub extends through the center hole of the second recording disk, wherein the first recording disk and the second recording disk each comprise a magnetic recording layer configured to store information.

A disk hub is configured to retain a magnetic recording medium including an annulus shape and a layer configured for magnetic recording. The disk hub includes a base plate portion for supporting an inner diameter area of the magnetic recording medium and a stem portion on the base plate portion. The stem portion includes a frustoconical portion on the base plate portion and a top portion on the frustoconical portion. At least the top portion of the stem portion includes a material with a hardness less than that of stainless steel. The disk hub can reduce surface damages (e.g., scratches) on the media surface during media testing.