Method of manufacturing a hard-disk drive using a bulk eraser

A method of reworking a hard-disk drive in manufacturing said hard-disk drive using a bulk eraser for erasing a servo pattern on a magnetic-recording disk, said method comprising:

• providing a bulk eraser having a gap consisting of at least a first portion providing a depth and a second portion providing a height, the bulk eraser producing magnetic-flux density in the second portion of a gap sufficient to erase a first servo pattern from a portion of said magnetic-recording disk, a hard-disk drive having an enclosure, a disk-stack having at least one magnetic-recording disk rotatably mounted on a spindle, and a drive motor having a rotor attached to said spindle for rotating said magnetic-recording disk inside said enclosure;
• configuring a plurality of magnets and a structure of said bulk eraser such that magnetic-flux density is oriented substantially parallel to a central plane in said second portion of said gap and in a substantially radial direction of the portion of said magnetic-recording disk when said hard-disk drive is inserted into said second portion of said gap;
• rotating said magnetic-recording disk in said hard-disk drive;
• inserting said hard-disk drive into said second portion of said gap of said bulk eraser such that a plane of said magnetic-recording disk of said hard-disk drive is oriented substantially parallel to said central plane in said second portion of said gap such that magnetic-flux density is oriented in said substantially radial direction of said portion of said magnetic-recording disk;
• erasing said first servo pattern from said portion of said magnetic-recording disk in said hard-disk drive located in said second portion of said gap;
• and
• removing said hard-disk drive from said second portion of said gap.

A method of preserving security of recorded information in a hard-disk drive in a computer system using a bulk eraser, said method comprising:

• removing said hard-disk drive from said computer system;
• providing a bulk eraser having a gap consisting of at least a first portion providing a depth and a second portion providing a height, the bulk eraser producing magnetic-flux density in the second portion of a gap sufficient to erase recorded information from a portion of said magnetic-recording disk, a hard-disk drive having an enclosure, a disk-stack having at least one magnetic-recording disk rotatably mounted on a spindle, and a drive motor having a rotor attached to said spindle for rotating said magnetic-recording disk inside said enclosure;
• configuring a plurality of magnets and a structure of said bulk eraser such that magnetic-flux density is oriented substantially parallel to a central plane in said second portion of said gap and in a substantially radial direction of the portion of said magnetic-recording disk when said hard-disk drive is inserted into said second portion of said gap;
• rotating said magnetic-recording disk in said hard-disk drive;
• inserting said hard-disk drive into said second portion of said gap of said bulk eraser such that a plane of said magnetic-recording disk of said hard-disk drive is oriented substantially parallel to said central plane in said second portion of said gap such that magnetic-flux density is oriented in said substantially radial direction of said portion of said magnetic-recording disk;
• erasing recorded information from said portion of said magnetic-recording disk in said hard-disk drive located in said second portion of said gap;
• and
• removing said hard-disk drive from said second portion of said gap.