Magnetic disk drive to alleviate damage from thermal asperity

#This application claims priority from Japanese Patent Application No. JP2005-052472, filed Feb. 28, 2005, the entire disclosure of which is incorporated herein by reference.

#The present invention relates to a magnetic disk drive including a magnetic disk medium that is rotationally driven and a magnetoresistive (MR) head that writes information onto or reads written information from magnetic disk media. More particularly, the invention is concerned with a magnetic disk drive that includes a function for preventing or alleviating trouble with the element section of an MR head due to the occurrence of thermal asperity on a magnetic disk.

#The surface of a magnetic disk (hereinafter, may also be referred to simply as the disk) which is a recording medium of a magnetic disk drive is formed of a number of very thin layers stacked on one another from the disk substrate side in order, such as an underlayer, a magnetic layer, a protective layer, and a lubricant layer. The disk surface also has precise planarity to allow an MR head (hereinafter, may also be referred to simply as the head) to fly over the disk stably with a very small vertical clearance and conduct data read/write operations. Even so, projections equivalent to the very small vertical clearance, dents, flaws, or other defects are present on the disk surface.

#FIG. 1 is a diagram showing a method of registering TA-causing sections according to an embodiment of the present invention.

#FIG. 2 is a configuration diagram of a magnetic disk drive according to the above embodiment of the present invention.

#FIG. 3 is a diagram showing an example of a table for registering TA-causing sections.

#FIG. 2 is a configuration diagram of a magnetic disk drive 200 according to an embodiment of the present invention. Disks 210 are each rotated by a spindle motor 234, and one MR head 212 is disposed on one associated surface of each disk 210. Each MR head 212 is installed on an associated head arm 211 that extends from a carriage 214 to the disk 210. The carriage 214 has a voice coil motor (VCM) 230 for driving the head arm 211, thus changing a position of the MR head 212, and reading data from specific positions on one or more of the disks 210 or writing data into these specific positions.

#A preamplifier 216 amplifies a signal that has been picked up by the MR head 212, and supplies the signal to a read/write channel 218. During write operations, the preamplifier 216 receives encoded write data signals from the read/write channel 218 and sends the signals to the MR head 212. During read operations, the read/write channel 218 detects data pulses from the reading signal supplied from the preamplifier 216, and demodulates the data pulses. The read/write channel 218 sends the demodulated data pulses to a disk data controller (DDC) 220. Furthermore, the read/write channel 218 encodes the write data received from the DDC 220, and supplies the encoded data to the preamplifier 216.

#After receiving data from a host computer (not shown), the DDC 220 writes the data onto the disk 210 through the read/write channel 218 and the preamplifier 216. The DDC 220 also transfers reading data that has been received from the disk 210, to the host computer. In addition, the DDC 220 functions as an interface between the host computer and a microcontroller 224. A buffer RAM 222 temporarily saves the data transferred between the DDC 220, the host computer, the microcontroller 224, and the read/write channel 218. The microcontroller 224 controls track-seeking and track-following functions in response to the read and write commands sent from the host computer.