KR100430729B1 - Method for automatically changing read parameter to optimize read channel of hdd using priority - Google Patents

Abstract

PURPOSE: A method for automatically changing read parameter to optimize a read channel of an HDD(Hard Disk Drive) is provided to recover a read error reliably and efficiently by automatically upwardly adjusting a priority of a read channel parameter having a high error recovery frequency when a data read error is generated in the HDD. CONSTITUTION: An error recovery frequency list is sorted in down order by the error recovery frequency(50). After executing a read parameter changing function set by the first item of the list, a microcontroller retries to read data(52). When the data is read again, it is checked that the error is recovered at the same position(54). If the read error is generated again, the microcontroller retries to read the data after executing the read parameter changing function set by the second item(56). If the error is not recovered, it is judged that the current executing item is the last item(60). In case of non-last item, the microcontroller retries to read the data by executing the read parameter changing function set by the next item. If the error is recovered, an automatic read parameter changing method is terminated after increasing the error recovery frequency of the corresponding item and resetting a standard read parameter(64).

Description

Automatic change of read factor for lead channel optimization

The present invention relates to a read channel optimization method of a hard disk drive, and more particularly, to a method of automatically changing a read factor for automatically adjusting a priority of a read channel factor having a high frequency of error recovery when a read error occurs.

A hard disk drive is an auxiliary memory device of a computer system that records and reads digital information by using a head and media. Although a hard disk drive has a relatively small probability of writing and reading due to the characteristics of the head and media, a write / read error generally occurs. The causes of these errors include external causes such as thermal noise, external electrical noise, mechanical disturbances caused by external vibrations or shocks, and uneven application of the magnetic material on the disk media. There are internal causes, such as when distortions occur.

Even when the cause of the above error occurs, the error is usually not generated when the magnitude of the noise / disturbance is small or the magnitude of the original read signal is large. In other words, when the signal to noise ratio is high, it has high resistance to the cause of error. On the other hand, in the hard disk drive, the digital information signal is written to the head / media through the read / write channel during recording, and the signal input from the head / media during reading is amplified by the preamplifier and converted into the digital information signal from the read / write channel circuit. Is restored. Therefore, the optimal reference recording / reading parameters should be set according to the recording / reading characteristics of the head / media for optimal signal recovery. It is common for each hard disk drive to have slightly different write / read characteristics due to variations in the characteristics of the head / media. Therefore, in order to compensate for this, an optimal recording / reading factor may be experimentally obtained for each set in the manufacture of a hard disk drive. In this case, the characteristic deviation may be larger according to the use environment, and accordingly, the probability of error occurrence may be increased at the input of noise / disturbance, which is the cause of the error. Therefore, by appropriately changing the recording / reading factor used as a reference, it is possible to lower the probability of error occurrence when reading data. Hereinafter, a conventional read factor changing method for changing the write / read factor to lower the probability of error occurrence when reading data will be described.

First, a table (Table 1 below) is prepared by enumerating the read factor items deemed effective. Then, if an error occurs during reading, the read function is attempted again after executing the function indicated by the first read factor change item of the table. If the error occurs again at the same position, execute the function indicated by the second read argument change item and try to read again. If the error does not recover, execute the function pointed to by the reader change item of the remaining items and try to read again until the error is recovered. When the error is recovered in this process, the preset reference reader is set again. If the error cannot be recovered even after performing all the functions described in the read factor change item table in the above-described manner, the read-out is aborted and the host computer executing the read command is reported that an unrecoverable error has occurred. Referring to Table 1 below with respect to the above error recovery process will be described an embodiment as follows.

First, if an error occurs when reading data, the control means of the hard disk drive sets the lead oat track, item 1 in Table 1 above, to 5% and attempts to reread. At this time, if a read error occurs at the same position, the control means attempts to reread by setting the lead off track, item 2, to -5%. If the error is not recovered upon rereading, the control means attempts to reread by sequentially executing the functions indicated by the read factor items in the table order until the error is recovered. When the error is recovered upon reread, the preset reference reader is set again. If the error is not recovered, an unrecoverable error is reported to the host computer.

The above-described conventional method for changing the read factor has an advantage that the error recovery process can be performed by a simple method, but it does not reflect the characteristics of each hard disk drive set and also has no adaptability according to the use environment. Therefore, there is a problem that the error recovery time may be delayed because the read factor items are sequentially changed even under a particular valid read factor item. For example, if an increase in the data threshold of a set of hard disk drives is a particularly effective item for error recovery than other read item items, then the error in the set must execute the 11th or 13th read item to recover the error. There is a good chance it can be. Therefore, in the conventional hard disk drive, there is a problem that data transmission is delayed because data reading is not normally performed for a long time when a data reading error occurs.

Accordingly, an object of the present invention is to provide a method of automatically changing a read factor that can recover a read error reliably and efficiently by automatically adjusting the priority of a read channel factor having a high error recovery frequency in real time when a data read error occurs in a hard disk drive. In providing.

In order to achieve the above object, the present invention provides a method for automatically changing read factors for read channel optimization of a hard disk drive.

In the event of a data read error, among the plurality of read factor change functions, the read factor change function with the highest frequency of error recovery is executed first to check whether the data read error is recovered, and the error of the corresponding read factor change function that was executed during the data read error recovery It is characterized by increasing the frequency of recovery.

1 is a block diagram of a typical hard disk drive.

2 is a flow chart of a read factor change process according to one embodiment of the invention.

Hereinafter, an operation according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the following description and drawings, numerous specific details are set forth in order to provide a more comprehensive understanding of the invention, such as reader items, reader change functions, and specific processing flows. It will be apparent to those skilled in the art that the present invention may be practiced without these specific details. And detailed descriptions of well-known functions and configurations that may unnecessarily obscure the subject matter of the present invention will be omitted.

1 shows a block diagram of a general hard disk drive, and shows an example of a hard disk drive having two disks 10 and four heads 12 corresponding thereto. Referring to FIG. 1, the disks 10 are typically stacked and mounted on the drive shaft of the spindle motor 34 and each disk surface corresponds to one head 12. The disk 10 typically consists of a plurality of tracks arranged concentrically and includes a parking zone and a data zone where the head 12 can be located when the drive is not in use (powered off). do. The head 12 is located on the surface of the disk 10 and is mounted to a vertically extending arm 14 of an annular voice coil motor (VCM) 28 arm assembly. The preamplifier 16 preamplifies and applies the read signal picked up by one of the heads 12 to the read / write channel circuit 18 when reading data. Encoded write data applied from the read / write channel circuit 18 is driven to drive the corresponding one of the heads 12 to be recorded on the disc 10. At this time, the preamplifier 16 selects one of the heads 12 under the control of a disk data controller (DDC) 36. The read / write channel circuit 18 decodes the read signal applied from the preamplifier 16 to generate read data RDATA. The read / write channel circuit 18 encodes the write data WDATA applied from the DDC 36 and applies it to the preamplifier 16. The read / write channel circuit 18 also demodulates the head position information which is a part of the servo information recorded on the disk 10 to generate a position error signal (PES). The PES generated from the read / write channel circuit 18 is applied to the A / D converter 20, and the A / D converter 20 converts the applied PES into a digital step value corresponding to its level so as to provide a microcontroller ( 22). The DDC 36 records data received from the host computer on the disk 10 through the read / write channel circuit 18 and the preamplifier 16 or transfers data reproduced from the disk 10 to the host computer. . The DDC 36 also interfaces the communication between the host computer and the microcontroller 22.

On the other hand, the microcontroller 22 controls the DDC 36 in response to the data write / read command received from the host computer, and controls the track search and track following. At this time, the micro controller 22 controls the track tracking by using the PES value input from the A / D converter 20 and responds to various servo control signals output from a gate array (not shown). Perform control. The D / A converter 24 converts a control value for position control of the heads 12 generated from the microcontroller 22 into an analog signal and outputs the analog signal. The VCM driver 26 generates a current I (t) for driving the actuator by a signal applied from the D / A converter 24 and applies it to the VCM 28. The VCM 28 located on the other side of the actuator having the heads 12 attached to one side moves the heads 12 horizontally on the disk 10 in response to the current direction and current level input from the VCM driver 26. Let's do it. The motor controller 30 controls the spindle motor driver 32 according to a control value for rotation control of the disks 10 generated from the microcontroller 22. The spindle motor driver 32 drives the spindle motor 34 to rotate the disks 10 under the control of the motor controller 30. The buffer memory 38 connected to the DDC 36 temporarily stores data transferred between the disk 10 and the host computer under the control of the DDC 36.

The ROM 40 connected to the microcontroller 22 stores a control program and an error recovery frequency list according to an embodiment of the present invention, and the error recovery frequency list is shown in Table 1 above. Assign one reader change function to each item in sequence, but generally assign the most effective reader change function first. The error recovery frequency list represents a set of read factor change functions valid for error recovery, and the error recovery frequency list has the same number of items as the number of elements of the set of read factor change functions and has a relocatable data structure. The read factor change function in the error recovery frequency list indicates the address of the read factor change function unique to each item, and the error recovery frequency indicates the frequency at which the error is recovered by performing the read factor change function when a read error occurs. And error recovery frequency of each item is initialized to "0" at drive manufacture.

2 is a flowchart illustrating a process of automatically changing a read factor according to an embodiment of the present invention. Hereinafter, referring to FIGS. 1 and 2, a process of automatically changing a read factor when a data read error occurs and recovering a read error will be described. Is as follows.

First, if an error occurs when reading data, the microcontroller 22 sorts the error recovery frequency list in descending order according to the error recovery frequency in step 50 of FIG. 2, and then proceeds to step 52. In step 52, the microcontroller 22 executes the read factor change function indicated by the first item of the sorted error recovery frequency list, and attempts to reread the data. Upon rereading the data, the microcontroller 22 proceeds to step 54 to check whether the error is recovered at the same location. If the error is not recovered and the data read error occurs again, the microcontroller 22 proceeds to step 56, executes the read factor change function indicated by the second item in the error recovery frequency list, and attempts to reread the data. Upon rereading the data, the microcontroller 22 proceeds to step 58 to check whether the error has been recovered. If the error is not recovered, the microcontroller 22 proceeds to step 60 to check whether the currently executing item is the last item. If the result of the check in step 60 is not the last item in the error recovery frequency list, the microcontroller 22 proceeds to step 62. In step 62, the microcontroller 22 attempts to reread the data by executing the read factor changing function indicated by the next item of the running item. Upon rereading the data, the microcontroller 22 returns to step 58 to check whether the error is recovered. If the error is recovered, the microcontroller 22 proceeds to step 64. Run sequentially to check if the error is recovering. If the error is recovered in the error recovery check step (54, 58), the microcontroller 22 proceeds to step 64 and increases the error recovery frequency of the item, resets the preset reference reader, and then The method for automatically changing the read factor according to the embodiment is finished. If the error is not recovered even after the read factor change function indicated by all items on the error recovery frequency list is executed, the microcontroller 22 reports the unrecoverable error to the host computer, and then reads the data according to an embodiment of the present invention. Ends the automatic argument change method.

In order to specify the method of automatically changing the read factor as described above, one embodiment will be described. When the first data read error occurs, the error recovery frequency of all items is "0". The order of is not rearranged. Therefore, the read factor changing function is sequentially performed from the first item of Table 1. If we assume that the error has been recovered when attempting to reread after executing the eleventh item of table 1, data threshold 5%, then the error recovery frequency of this item is increased to 1. Thereafter, a preset reference read factor is set, and then data reading is performed. This error recovery operation causes the error recovery frequency list to be in an unsequential order. In other words, the error recovery frequency of the 11th item is the highest. When the error recovery frequency list is sorted at the next data read error, the data threshold 5% upward adjustment function is rearranged as the first item. Therefore, in the case of a data read error caused by the same cause, error recovery can be most efficiently performed. Therefore, as read errors occur and recover for various reasons, the error recovery frequency list gradually rearranges the most efficient read factor change function for error recovery, and then the optimized read factor change function is executed first for each drive set. The error recovery time can be shortened.

As described above, the present invention has the advantage that the error recovery operation in any arbitrary hard disk drive set can be adapted to follow a reliable and efficient procedure optimized for that particular set, thereby reducing the error recovery time in the event of a data read error.

Claims (3)

In the automatic change of the read factor for the read channel optimization of the hard disk drive, A process of checking whether a data read error is recovered by first executing a read factor change function having a high error recovery frequency among a plurality of read factor change functions when a data read error occurs; A method for automatically changing a read factor, characterized by increasing the error recovery frequency of the corresponding read factor change function, which has been executed during data read error recovery. The method of claim 1, wherein the error recovery frequency is automatically sorted in descending order every time a data read error occurs. The method of claim 1, further comprising resetting a predetermined reference reading factor after increasing the error recovery frequency.