Enlarged substrate for magnetic recording medium
Apparatus and method for magnetic recording media. A rotatable magnetic recording disc has an outermost annular sidewall that extends at nominally 97 millimeters, mm for a 3-½ inch form factor data storage device or at nominally 67 mm for a 2-½ inch form factor data storage device. The rotatable magnetic recording disc further has a disc shaped substrate of metal or glass, and a magnetic recording layer supported by the disc shaped substrate and configured to magnetically record data along concentric tracks.
1. An apparatus comprising a rotatable magnetic recording disc for a 3-½ inch form factor data storage device, the rotatable magnetic recording disc comprising an outermost annular sidewall that extends at an outermost diameter of nominally 97 millimeters, mm, a disc shaped substrate of metal or glass, and a magnetic recording layer supported by the disc shaped substrate and configured to magnetically record data along concentric tracks, the disc shaped substrate having a nominally flat top surface that extends between an innermost diameter toward the outermost annular sidewall to a radius of rolloff (ROR) point at a selected radius, and a relief zone that extends from the ROR point toward the outermost annular sidewall with a continuous change in elevation with respect to the nominally flat top surface, the selected radius of the ROR greater than 45.5 mm from a center of the disc shaped substrate.
2. The apparatus of claim 1 , wherein an outermost track of the concentric tracks is disposed at a second selected radius of from nominally 46.0 mm to nominally 46.5 mm.
3. The apparatus of claim 1 , wherein the rotatable magnetic recording disc further comprises an inner annular sidewall extending at an innermost diameter of nominally 25 mm.
4. The apparatus of claim 1 , wherein the relief zone is characterized as at least one of a duboff (DO) zone or a ski jump (SJ) zone.
5. The apparatus of claim 1 , wherein the rotatable magnetic recording disc further comprises opposing top and bottom planar surfaces, wherein the magnetic recording layer is a first magnetic recording layer adjacent the top planar surface, and wherein the rotatable magnetic recording disc further comprises a second magnetic recording layer adjacent the bottom planar disc.
6. The apparatus of claim 1 , further comprising a base deck housing member for a 3-½ inch form factor HDD and a spindle motor supported by the base deck housing member, the spindle motor configured to rotate the rotatable magnetic recording disc at a selected rotational velocity.
7. The apparatus of claim 6 , wherein the rotatable magnetic recording disc further comprises a protective overcoat layer that covers the magnetic recording layer.
8. The apparatus of claim 6 , wherein the rotatable magnetic recording disc further comprises at least one interlayer disposed between the magnetic recording layer and the disc shaped substrate.
9. The apparatus of claim 6 , wherein an outermost track of the concentric tracks is disposed at a second selected radius of from nominally 46.0 mm to nominally 46.5 mm.
10. The apparatus of claim 6 , wherein the rotatable magnetic recording disc further comprises an inner annular sidewall extending at an innermost diameter of nominally 25 mm.
11. The apparatus of claim 6 , wherein the relief zone is characterized as at least one of a duboff (DO) zone or a ski jump (SJ) zone.
12. The apparatus of claim 6 , further comprising a base deck housing member for a 2-½ inch form factor HDD and a spindle motor supported by the base deck housing member, the spindle motor configured to rotate the rotatable magnetic recording disc at a selected rotational velocity.
13. An apparatus comprising a rotatable magnetic recording disc for a 2-½ inch form factor data storage device, the rotatable magnetic recording disc comprising an outermost annular sidewall that extends at an outermost diameter of nominally 67 millimeters, mm, a disc shaped substrate of metal or glass, and a magnetic recording layer supported by the disc shaped substrate and configured to magnetically record data along concentric tracks, the disc shaped substrate having a nominally flat top surface that extends between an innermost diameter toward the outermost annular sidewall to a radius of rolloff (ROR) point at a selected radius, and a relief zone that extends from the ROR point toward the outermost annular sidewall with a continuous change in elevation with respect to the nominally flat top surface, the selected radius of the ROR greater than 31.5 mm from a center of the disc shaped substrate.
14. An apparatus comprising a magnetic recording disc comprising a disc-shaped substrate on which a magnetic recording layer is formed, the disc-shaped substrate having an outermost annular sidewall at a first radius of nominally 33.5 millimeters, mm or 47.5 mm, a nominally fiat top surface that extends between an innermost diameter toward the outermost annular sidewall to a radius of rolloff (ROR) point at a second radius, and a relief zone that extends from the ROR point toward the outermost annular sidewall with a continuous change in elevation with respect to the nominally flat top surface, the second radius of the ROR point being less than 2 mm from the first radius of the outermost annular sidewall.
15. The apparatus of claim 14 , wherein an outermost track of a plurality of concentric tracks defined in the magnetic recording layer is disposed at from nominally 1.0 mm to nominally 1.5 mm from the outermost annular sidewall.
16. The apparatus of claim 14 , wherein the relief zone is characterized as at least one of a duboff (DO) zone or a ski jump (SJ) zone.
17. The apparatus of claim 14 , wherein the first radius is nominally 33.5 mm to provide a 67 mm diameter recording disc for a hard disc drive (HDD) having a 2-½ inch form factor.
18. The apparatus of claim 14 , wherein the first radius is nominally 47.5 mm to provide a 97 mm diameter recording disc for an HDD having a 3-½ inch form factor.
19. The apparatus of claim 14 , wherein the rotatable magnetic recording disc further comprises an inner annular sidewall extending at an innermost diameter of nominally 25 mm.
20. The apparatus of claim 14 , wherein the relief zone comprises a third radius between the first radius and the second radius characterized as an outermost point on the magnetic recording disc at which an associated read/write transducer can be maintained with sufficient stability to write data to and read data from the magnetic recording layer, and wherein an outermost track of a plurality of concentric tracks defined in the magnetic recording layer is disposed at a fourth radius between the second radius and the third radius.