Apparatus and method to improve read/write speed of disk drive system

A disk drive system, comprising:

• a discoid medium which rotates about its rotation axis and stores data;
• an actuator which has a head for reading or writing data from or in the discoid medium and bidirectionally rotates about its bidirectional-rotation axis;
• and
• a housing which is constituted of a boxy base and a flat cover made of a material different from the base in linear expansion coefficient, wherein the housing has a structure in which the tilt of the rotation axis and the bidirectional-rotation axis in the housing width direction due to the difference in linear expansion coefficient are suppressed, and wherein the size of the discoid medium is smaller than that of a discoid medium corresponding to the form factor of the housing.

A disk drive system comprising:

• a discoid medium which rotates about its rotation axis and stores data;
• an actuator which has a head for reading or writing data from or in the discoid medium and bidirectionally rotates about its bidirectional-rotation axis;
• and
• a housing which has a predetermined width and houses the discoid medium and the actuator, wherein the bidirectional-rotation axis of the actuator is set eccentrically in the rotational direction of the discoid medium from the width-directional center of the housing, and wherein the size of the discoid medium is smaller than that of a discoid medium corresponding to the form factor of the housing.

A hard disk drive, comprising:

• a disk assembly in which a magnetic disk having a diameter of 75 mm or less to magnetically store data is set to a spindle so as to be rotatable;
• a rotary actuator which has a magnetic head for storing or reproducing data in or from the magnetic disk, seeks the magnetic head on the magnetic disk, and bidirectionally rotates about a pivot;
• and
• an enclosure case of a 3.5″ form factor having a predetermined width to house the disk assembly and the rotary actuator, wherein the spindle and the pivot are set to the width-directional center of an enclosure case or eccentrically set in the rotational direction of the magnetic disk from the width-directional center of the enclosure.

A hard disk drive, characterized by comprising:

• a disk assembly in which a magnetic disk having a diameter of 60 to 75 mm to magnetically store data is set to a spindle so as to be rotatable;
• a spindle motor which rotates the disk assembly and has a rated rotational speed of 12,000 rpm or more;
• a rotary actuator which has a magnetic head for storing or reproducing data in or from the magnetic head, seeks the magnetic head on the magnetic disk, and bidirectionally rotates about a pivot;
• and
• an enclosure case of a 3.5″ form factor for housing the disk assembly and the rotary actuator.