Data storage apparatus and disk fixing method for preventing the deformation of disks by regulating where the storage apparatus is fixed to the disk

A method for fixing a disk for recording data to a rotating member for rotating the disk, the disk having obverse and reverse sides, a center hole, a portion of reduced or increased thickness situated around an inner peripheral edge defining the center hole, and a portion of constant thickness situated outside the portion of reduced or increased thickness and having surfaces on the obverse and reverse sides substantially parallel to each other, said method comprising the steps of:

• mounting the disk on the rotating member in an manner such that an annular supporting portion on the rotating member is located coaxially with the center hole of the disk and faces the portion of constant thickness on the disk in a predetermined position at a distance of 1.5 t from the inner peripheral edge of the disk, where t is the thickness of the disk;
• and
• attaching a press member, having an annular press portion, to the rotating member in a manner such that the press portion is located coaxially with the center hole of the disk and faces the portion of constant thickness on the disk in said predetermined position, so as to press the disk towards the supporting portion.