Disk device with exposed inner surface regions for improved cover coupling

A disk device comprising:

• a magnetic disk;
• a base having an internal space in which the magnetic disk is disposed, the base including first inner surface surrounding the magnetic disk and extending in a first direction parallel to a rotation axis of the magnetic disk, a supporting surface that is connected to an end of the first inner surface in the first direction and extending in a second direction orthogonal to the first direction, a second inner surface that is further away from the rotation axis than the first inner surface, connected to the supporting surface, and extending in the first direction, and an end face that is connected to an end of the second inner surface in the first direction and extending in the second direction;
• a film that covers the first inner surface, the supporting surface, and first, second, and third parts of the second inner surface, each of which extends partially around the rotation axis, and that does not cover the end face, a fourth part of the second inner surface that is between the first and second parts of the second inner surface, a fifth part of the second inner surface that is between the first and third parts of the second inner surface, and a sixth part of the second inner surface that is between the second and third parts of the second inner surface;
• an inner cover that is supported by the supporting surface, surrounded by the second inner surface, and covering the internal space of the base;
• and
• an outer cover that is coupled to at least a portion of the base and covering the inner cover.