Apparatus and method for preventing data corruption in disk drives from mechanical shock during write operations

A method for preventing data corruption on a disk of a disk drive caused by mechanical shock experienced by said disk drive while writing data to an original data track with a data head, said method including the steps of:

• sensing a mechanical shock having a magnitude exceeding a predetermined threshold with a mechanical shock sensor including a beam having a first end, a second end and a piezoelectric film strain sensor attached along a length of said beam, said second end having a mass of between 0.01 gm and 1.0 gm attached thereto, an electrical output of said piezoelectric film strain sensor carried on a pair of conductors;
• interrupting the write current to the data head of said disk drive during said mechanical shock;
• storing information identifying interrupted data being written when said write-current is interrupted;
• repositioning the data head to the original data track;
• and
• rewriting said interrupted data.

A method for preventing data corruption on a disk of a disk drive caused by a mechanical shock experienced by said disk drive while writing data to a data track with a data head, said method including the steps of:

• temporarily storing in a buffer a block of data to be written to the disk;
• initiating a disk-write operation;
• temporarily storing a shock indicator signal in a selected storage location if a mechanical shock having a magnitude exceeding a predetermined threshold is sensed, said shock indicator signal derived from a mechanical shock sensor including a beam having a first end, a second end and a piezoelectric film strain sensor attached along a length of said beam, said second end having a mass of between 0.01 gm and 1.0 gm attached thereto, an electrical output of said piezoelectric film strain sensor carried on a pair of conductors;
• interrupting the write current to the data head if said mechanical shock is sensed;
• examining said selected storage location for said shock indicator signal after completion of said disk-write operation;
• and
• repositioning the data head to the data track and rewriting said block of data if said shock indicator signal is present.

A disk drive memory storage unit comprising:

• at least one disk surface capable of being rotated about a first axis;
• a voice coil actuator capable of rotary motion about a second axis parallel to said first axis;
• a head arm mounted on said voice coil actuator;
• a write head mounted on said head arm and positioned over said disk surface by said voice coil actuator;
• said write head adapted to write information to a track of said disk surface in response to a write-current passed through said write head;
• mechanical shock sensing means for sensing a mechanical shock having a magnitude exceeding a predetermined threshold and producing a shock-present signal in response thereto, said mechanical shock sensing means including a beam having a first end, a second end and a piezoelectric film strain sensor attached along a length of said beam, said second end having a mass of between 0.01 gm and 1.0 gm attached thereto, an electrical output of said piezoelectric film strain sensor carried on a pair of conductors;
• write disable means, responsive to said shock-present signal, for interrupting said write-current to said write head;
• interrupted-data identifying means, responsive to said shock-present signal, for identifying interrupted data being written at the time said shock-present signal indicates the presence of a mechanical shock exceeding said predetermined threshold;
• and
• recovery means for repositioning said write head over said track and rewriting said interrupted data if said shock-present signal indicates the presence of a mechanical shock exceeding said predetermined threshold.