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

Claim 2

Apparatus for preventing data corruption on a disk of a disk drive due to a mechanical shock experienced by said disk drive while writing data to a selected data track on said disk by passing a write-current to a write head disposed on a head arm of an actuator, said apparatus comprising: mechanical shock sensing means for sensing 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 the write current to the 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 the mechanical shock; and recovery means, responsive to said interrupted-data identifying means, for repositioning the write head over the selected track and for rewriting said interrupted data.

Claim 3

The apparatus of claim 1 wherein said first end of said mechanical shock sensing means is fixed along a mounting axis parallel to an axis of rotation of the actuator so as to permit rotational movement of said beam about said mounting axis in response to a shock applied to the disk drive about said axis of rotation.

Claim 4

The apparatus of claim 2 wherein said mechanical shock sensing means comprises an accelerometer.

Claim 5

The apparatus of claim 3 wherein said mechanical shock sensing means comprises a cantilever-beam accelerometer.

Claim 6

The apparatus of claim 3 wherein said mechanical shock sensing means comprises a single-beam cantilever-beam accelerometer.

Claim 7

The apparatus of claim 3 wherein said mechanical shock sensing means comprises a dual-beam cantilever-beam accelerometer having a beam positioned on an axis of rotation of the head arm.

Claim 12

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.

Claim 13

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.

Claim 14

A disk drive memory storage unit according to claim 9 wherein said first end of said beam is mounted along a third axis parallel to said first axis so as to permit rotational movement of said beam about said third axis in response to a shock applied to the disk drive about said first axis.