KR100432504B1 - Method for retrying off-track read to data off-track write, particularly for reading data off-track written in process that head is shaken right and left by unstable settling or instantaneous shock - Google Patents

Abstract

PURPOSE: A method for retrying off-track read to data off-track write, particularly for reading data written off-track in a process that head is shaken right and left by unstable settling or an instantaneous shock is provided to read data written off-track by controlling a head so as to proceed with the locus of a sine wave shape in direction of a track center line. CONSTITUTION: A head is on a track having data written off-track(100). The data are read while the head becomes off from the track as much as the maximum track amount in one direction from a servo sector prior to two sectors from a data sector having an error(102), and the head becomes off from the track as much as the maximum track amount in direction opposite to the one direction from a servo sector immediately before the data sector having the error(104). If an read error is generated, the data are read while the head becomes off from the track as much as the maximum track amount in direction opposite to the one direction from the servo sector prior to two sectors from the data sector having the error(106-108), and the head becomes off from the track as much as the maximum track amount in the one direction from the servo sector immediately before the data sector having the error(110).

Description

Offtrack lead retry method for data offtrack writes

The present invention relates to a hard disk drive, and more particularly to a retry method for off-track writes.

A hard disk drive is an auxiliary memory device that receives and stores data applied from the host under the control of a host (generally a personal computer) and replays the data to the host. Hard disk drives are largely divided into a hard disk assembly (HDA) and a printed circuit board assembly (PCBA). In the hard disk assembly (HDA), parts such as a spindle motor, a disk, an actuator, a voice coil motor, and the like are installed on a base plate, and a cover is provided to protect these parts and to block external impurities. The printed circuit board assembly (PCBA) has various integrated circuits (ICs) for circuit operation of a hard disk drive.

The hard disk assembly (HDA) has a spindle motor for rotating the disk. The spindle motor is controlled by a spindle motor drive IC in a printed circuit board (PCB). Control signals generated from the spindle motor driver IC are generally transmitted to the spindle motor through a flexible printed circuit (FPC) connected to a connector on a printed circuit board (PCB).

1 is a block diagram of a conventional hard disk drive. Referring to FIG. 1, the disks 10 are rotated by a spindle motor 34. Each of the heads 12 is located on the corresponding one of the disks 10, and the disks 10 from the E-block assembly 14 coupled with the rotary voice coil actuator 30. It is installed to correspond to each of the support arms extending to the side. The preamplifier 16 preamplifies the signal picked up by one of the heads 12 at the time of read, and applies the analog read signal to the read / write channel circuit 18. Encoded write data applied from the read / write channel circuit 18 is written onto the disc through the corresponding one of the heads 12. The read / write channel circuit 18 detects and decodes a data pulse from the read signal applied from the preamplifier 16 and applies the read / write channel circuit 18 to the DDC (Disk Data Controller) 20 and applies the write data applied from the DDC 20. Decode and apply to preamplifier 16. The DDC 20 writes data received from the host computer through the read / write channel circuit 18 and the preamplifier 16 to the disk or reads data from the disk and transmits the data to the host computer. The DDC 20 also interfaces the communication between the host computer and the microcontroller 24. The buffer RAM 22 temporarily stores data transmitted between the host computer and the microcontroller 24 and the read / write channel circuit 18. The microcontroller 24 controls track search and track following in response to a read or write command received from the host computer. The memory 26 stores the execution program of the microcontroller 24 and various setting values. The servo driver 28 generates a driving current for driving the actuator 30 in response to a signal for controlling the position of the heads 12 provided by the microcontroller 24 and applies it to the voice coil of the actuator 30. do. The actuator 30 moves the heads 12 on the disks 10 in correspondence with the direction and level of the drive current applied from the servo driver 28. The spindle motor driver 32 rotates the disks 10 by driving the spindle motor 34 according to a control value for the rotation control of the disks 10 generated from the microcontroller 24.

The process of writing data to the disk 10 in the hard disk drive as shown in FIG. 1 is generally performed in the order of track seek, settling, and write. In this write process, off-track write may occur when the criterion for setting the second stage setting is too loose or when there is an external impact among the third stage lights. If an off track write occurs, an error occurs during data read. To solve this problem, the off-track retry method is conventionally used. That is, the off-tracked data is read by reading data while changing the head to ± 5%, ± 10%, and so on.

However, in the conventional off-track retry method, data can be read only when data is off-tracked to one side of the track center line. However, when data is off-tracked in the process of shaking the head from side to side due to instability or instantaneous impact of settling during data writing, the written data may be off-tracked on the left and right regions of the center line of the track. In this case, data cannot be read by the conventional off-track retry method.

Accordingly, an object of the present invention is to provide an off-track retry method that can lead to off-track written data in the process of shaking the head from side to side due to instability or instantaneous shock of settling during data write.

In accordance with the above object, the present invention, in the off-track lead retry method for reading the off-track written data in the process of shaking the head from side to side due to instability or instantaneous impact of the settling during data writing, the off-track The driving of the head is controlled in a predetermined section of the track where the written data exists and the driving of the head is performed in the direction of the track center line while reading the tracked data.

1 is a block diagram of a conventional hard disk drive block

2 is a preferred control flow diagram in accordance with an embodiment of the present invention.

3 is a second off track read retry subroutine flow chart of FIG.

4 is a view for explaining a retry method for the off-track light according to an embodiment of the present invention;

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, it should be noted that like elements are denoted by like reference numerals wherever possible. In addition, detailed descriptions of well-known functions and configurations that may unnecessarily obscure the subject matter of the present invention will be omitted.

2 is a control flow chart for re-tracking a re-tracking retry according to an embodiment of the present invention, a first off-track read retry process of reading data while off-tracking the head in a predetermined direction in response to a data read failure; If the data read fails as a result of performing the first off-track read retry process, the off-track written data moves toward the track center line in a predetermined section of the track where the data is written and moves the head to have a sinusoidal trajectory to write the data written to the section. The second off-track lead retreading process is performed. The first off track retry process is a process used in the existing method, and the second off track retry process is an additional process according to an embodiment of the present invention. In the off-track retry process according to the embodiment of the present invention, it is preferable that the first off-track retry process and the second off-track retry process are performed sequentially, as described above. Only the drawing process may be performed.

3 is a flowchart illustrating a second off-track read retry subroutine of FIG. 2, and FIG. 4 is a diagram for describing a retry method for an offtrack light according to an exemplary embodiment of the present invention. Referring to FIG. 4, when the head is swayed left and right due to instability or instantaneous impact of settling during data writing, data is off-track written as in the original letter number ① ② of FIG. 4.

In more detail, it is assumed that the position where data is written when off track written in the sector B on a predetermined track as the original character number ① ②. The position of ① is in the off-track area in the (-) direction, that is, the inner direction from the track center line, and the position of ② is in the off-track area in the (+) direction, that is, the outer direction, in the track center line. In FIG. 4, SVO0, SVO1, and SVO2 mean servo sectors, and A and B mean data sectors.

A preferred offtrack read retry method when data is offtrack written as in the example of FIG. 4 will be described with reference to FIGS.

When reading data, the microcontroller 24 turns on the track to the target track (for example, the B data sector of FIG. 3) to read the head, and reads data in step 60 of FIG. If the lead fails, the process proceeds to step 64 to perform the first off-track lead retry. The first offtrack read retry is to read data while changing the head to ± 5%, ± 10%, etc. at the track centerline. This method is a conventional offtrack read retry method. In the case of the data recorded in sector B of FIG. 3, all data is not read by the first off-track read retry.

In operation 66, the microcontroller 24 determines whether the read failure is performed by the normal off-track read retry. If the read failure fails, the microcontroller 24 performs the second off-track read retry. The second off-track read retry is a gist of the present invention, and performs data reading by moving the head in the (-) → (+) direction or the (+) → (−) direction with respect to the track center line.

This will be described in more detail with reference to FIG. 3, which is the second offtrack read retry subroutine. The microcontroller 24 first starts on-track the head to the desired track, i.e., the track where the error occurred, in step 100. After that, the flow proceeds to step 102, where the head is read off by x off-track amount in the positive direction before two servo sectors of the data sector B in which an error occurs (i.e., in the SVO0 servo sector). Thereafter, in step 104, the data is read out by off-tracking an amount of x off-track in the negative direction in the servo sector immediately before the data sector B in which the error occurs. In this case, the traveling direction of the head on the track is the same as the reference numeral 50 of FIG.

Thereafter, the microcontroller 24 determines whether a data read error occurs in step 106. If a data read error occurs, the microcontroller 24 proceeds to steps 108 and 110 in a direction opposite to that performed in steps 102 and 104 above. Off-track the head to read data. That is, the head is first read off data by the maximum x off track amount in the negative direction and then the data is read off by the maximum x off track amount in the (+) direction. In this case, the traveling direction of the head on the track is the same as 40. According to the assumption of the data position shown in Fig. 4, when the head goes in the traveling direction indicated by reference numeral 40, all the offtrack written data can be read.

If this does not work, the second off-track read retry is performed several times while increasing the off-track amount. That is, the microcontroller 24 determines whether it is a data read error in step 112, and if it is a data read error, the process proceeds to step 114 and determines whether the second off-track read retry has exceeded the preset number N. If it is not exceeded, the process proceeds to step 116 to increase the off-track amount x by one step, and then repeats the process from step 100 described above. If this process is repeated, the off-tracked data can be read in the process of shaking the head from side to side due to instability or instantaneous impact of settling during data writing.

In the above description of the present invention, specific embodiments have been described, but various modifications can be made without departing from the scope of the present invention. Therefore, the scope of the present invention should not be defined by the described embodiments, but should be defined by the equivalents of the claims and the claims.

As described above, the present invention proceeds toward a track centerline in a predetermined section of a track where the off-track written data is written, and moves the head to have a sinusoidal trajectory to read the data written in the section. Instability or instantaneous shocks can lead to off-track data read while the head swings from side to side.

Claims (3)

In the off-track lead retry method for reading data off-track written in the process of shaking the head from side to side due to unstable settling or momentary impact during data write, A first step of ontracking the head to a track with offtracked data; The data is read by off-tracking the head by a preset maximum track amount in one direction from the servo sectors two sectors before the failed sector of data, and opposite to the one direction from the servo sector immediately before the failed data sector. A second process of off-tracking the head by a predetermined maximum track amount in the direction and reading data to check for a lead error occurrence; When the read error occurs, data is read off the head by a predetermined maximum track amount in the opposite direction from the servo sector before two sectors of the failed data sector, and the data is read immediately before the failed data sector. And a third process of off-tracking the head by a predetermined maximum track amount from the servo sector in the one direction and reading data to check the occurrence of a read error. The offtrack read retry method of claim 1, wherein, in the third process, if a data read error occurs, the offtrack read retry method is performed several times and the data read retry is performed. In the off-track lead retry method for reading data off-track written in the process of shaking the head from side to side due to unstable settling or momentary impact during data write, A first step of ontracking the head to a track with offtracked data; A second process of gradually off-tracking the head in one direction and one direction opposite to a maximum track amount preset to have a sinusoidal trajectory in the track with the off-track written data; And a third process of controlling the head having the trajectory of the sine wave by the second process to proceed in the direction of the center line of the track.