JPH07311906A - Data-recording/reproducing apparatus and method for processing error - Google Patents

Abstract

PURPOSE:To reduce a generation frequency of read errors by adjusting a parameter of a read/write circuit with the utilization of a retrial operation every time a read error occurs, and eventually setting the parameter to be an optimum value. CONSTITUTION:If a read error is generated when a read/write operation is executed in accordance with a request to read, to write or to verify from a host computer, a CPU 4 carries out a retrial operation for a predetermined number of times or until the error is recovered. At the retrial operation, the CPU 4 updates an average value of a parameter of a read/write circuit 8 set when the apparatus is manufactured. Moreover, the CPU 4 sets the parameter updated when the error is recovered by the retrial operation as an optimum value in the read/write circuit 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk apparatus, and more particularly to a data recording / reproducing apparatus having a function of executing a retry operation when an error occurs during a read / write operation.

[0002]

2. Description of the Related Art Conventionally, for example, a hard disk device (HDD), which is a magnetic disk device, reproduces read data from a read signal read from a disk by a head,
It also has a read / write circuit for converting write data to be recorded on the disk into a write signal (write current).

Recently, as the read / write circuit, a read / write IC (integrated circuit) in which components such as an amplifier circuit and a low pass filter are integrated is used. In such a read / write IC, various parameters such as a data strobe offset value, a cutoff frequency of a low pass filter, and a boost amount (dB) can be externally set by a CPU (controlling microprocessor) of an HDD. It has become. The data strobe offset value is the peak position of read data read from the disk and is a PLL (phase-locked l).
It is a value indicating how much margin is provided before and after in the reference clock created by the (loop) circuit. PLL
The circuit is a circuit for separating the data and the clock when reproducing the read data.

In the HDD, the head moves to the cylinder to be accessed in response to read, write, and verify (data inspection) requests from the host computer, and data read / write operations are performed on the disk. To do. A read error may occur during this read / write operation. The read error includes an ID read error, a DAM error and an ECC error. I
The D read error is an error in which the data area indicating the sector address cannot be read in the ID information recorded in the ID area of each sector. The DAM error is a data address mark error and is an error in which the area indicating the beginning of valid data cannot be read. Furthermore, E
The CC error is an error in which erroneous data generated during data transfer cannot be automatically corrected. Even in the write operation, when the sector to be accessed is detected, the ID
Read errors may occur.

When such a read error occurs, a normal HDD has a function of executing a retry operation. That is, the read / write operation by the head is re-executed. For example, when an ID read error occurs, the reading operation of the sector address from the ID area of the designated sector is re-executed.

[0006]

Conventionally, a read error such as an ID read error occurs when a read / write operation is performed on a disk in response to a read, write or verify request from a host computer. May occur. When this read error occurs, the conventional HDD executes a retry operation which is a re-execution of the read / write operation.

By the way, as described above, the read / write circuit is set with parameters such as the data strobe offset value for determining the read / write characteristics.
Normally, this parameter is set to an average value calculated at the time of designing the HDD, and is not changed after the HDD is manufactured. Therefore, when a read error occurs, the retry operation is executed under exactly the same conditions according to the parameters before the error occurred. For this reason, if there is a considerable error between the average value and the optimum value set when the HDD is designed, the error will not be recovered even if the retry operation is executed, and the frequency of read errors will increase. It becomes a situation.

An object of the present invention is to set a parameter to an optimum value by adjusting a parameter of a read / write circuit by utilizing a retry operation every time a read error occurs, and reduce the frequency of occurrence of the read error. It is to provide a data recording / reproducing apparatus capable of performing the above.

[0009]

According to the present invention, there is provided a read / write circuit means capable of externally setting a parameter for determining a read / write characteristic, and an HDD having a function of executing a retry operation when a read error occurs. Etc. is a data recording / reproducing device. This apparatus has a retry control means for executing a retry operation of a read / write operation up to a predetermined number of times or until error recovery, and a parameter updating means for setting a parameter updated at the time of error recovery in the read / write circuit means.

[0010]

According to the present invention, when the read / write operation is executed in response to the read, write and verify requests from the host computer. When a read error occurs, the retry control means causes the retry operation to be executed a predetermined number of times or until error recovery. The parameter updating means updates the average value of the parameters of the read / write circuit means set at the time of manufacturing the device at the time of the retry operation. further,
The parameter updating means sets the updated parameter in the read / write circuit means as an optimum value when the error is recovered by the retry operation.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the main part of the HDD of the embodiment,
FIG. 2 is a flow chart for explaining the operation of the embodiment.

As shown in FIG. 1, the HDD of the embodiment is
According to the command of the host system (computer),
It has a read / write circuit 8 for recording data on the disk 2 by the head 1 or reproducing the data read by the head 1. One or a plurality of disks 2 are provided, and in the same embodiment, there is one disk 2 for convenience. Further, a plurality of heads 1 are provided corresponding to both sides of one disk 2.

The head 1 has a head actuator 14a.
Held in. The head actuator 14a is rotationally driven by the voice coil motor (VCM) 14 to move the head 1 in the radial direction (arrow) of the disk 2.
The VCM 14 controls the VCM driver 1 under the control of the CPU 4.
A drive current is supplied from 3 to control the drive. The disk 2 is rotationally driven by the spindle motor 3 and rotates at high speed. The spindle motor 3 is driven by the motor driver 12.

The read / write circuit 8 is a read / write I.
C has a parameter setting circuit 8a for externally setting various parameters such as a data strobe offset value for determining read / write operation characteristics. The read / write circuit 8 is roughly divided into a write circuit system and a read circuit system that convert the write data (NRZ encoded data) transferred from the host system into a write signal (write current) current and supply it to the head 1. . In the embodiment, the description of the write circuit system is omitted, and only the read circuit system will be described.

The read circuit system of the read / write circuit 8 is
Normally, a head amplifier, AGC (automatic)
It has a gain control) amplifier, a low-pass filter circuit (LPF), a binarization circuit, a PLL circuit, and a decoder. The read circuit system reproduces digital read data (NRZ encoded data) from the read signal (analog signal) read by the head 1 and outputs it to the HDC (hard disk controller) 6.

Here, the AGC amplifier is an amplifier circuit for maintaining the read signal from the head amplifier at a predetermined level. The LPF is a filter for removing noise in a predetermined high band, and a cutoff value (cutoff frequency) parameter and a boost amount (dB) parameter are set by the CPU 4. The binarization circuit is a circuit for generating a read pulse from the read signal output from the LPF. The PLL is a circuit for detecting a data pulse from the read pulse generated by the binarization circuit. The decoder is a circuit for decoding the detected read data into NRZ encoded data.

The HDC 6 constitutes an interface between the HDD and the host system, and exchanges read / write data and various interface signals (including read, write, and verify commands from the host system). The buffer memory 7 is controlled by the HDC 6 and is an R for temporarily storing read / write data.
AM.

The CPU 4 is a control microprocessor (microcontroller) for executing various control processes such as servo control. In the embodiment, the CPU 4 performs the retry operation when the read error occurs and the read / write circuit 8
The parameter update process of is executed. ROM5 is CPU
4 is a read-only memory that stores a program for determining the operation of No. 4 and a parameter update table necessary for parameter update processing.

The servo circuit 9 processes the read signal obtained by reading the servo data recorded on the disk 2 among the read signals output from the read / write circuit 8,
A read signal corresponding to burst data of the servo data is sampled and output to the A / D conversion circuit 10. Further, the read signal corresponding to the cylinder address in the servo data is processed and output to the CPU 4 as cylinder address information. Here, the burst data is
This data is used to position the head 1 at the center of the track of the disk 2. A / D conversion circuit 10
Converts the input sampling signal into a digital value and outputs it as burst data to the CPU 4. CPU
4 processes the burst data so that the head 1
The amount of positional deviation with respect to the center of the track is calculated. The cylinder address is information indicating the absolute position of the track on the disk 2.

Based on the servo data (cylinder address and burst data) output from the servo circuit 9, the CPU 4 outputs a control amount for positioning the head 1 at the center of the target track to the D / A conversion circuit 11. . D /
The A conversion circuit 11 converts the voltage into a voltage according to the control amount from the CPU 4 and outputs the voltage to the VCM driver 13.

Next, the operation of the embodiment will be described. In this embodiment, when the HDD is manufactured (before shipment as a product), C
The PU 4 sets, for example, a data strobe offset value, which is a parameter for determining the read / write operation characteristic, in the read / write circuit 8 via the parameter setting circuit 8a. Here, the data strobe offset value is a value indicating how much margin the peak position of the read data read from the disk 2 has before and after in the reference clock created by the PLL circuit of the read / write circuit 8. Is. The CPU 4 sets the average value of the data strobe offset values as the initial value at the time of manufacturing.

Next, the HDD is shipped as a product and executes read / write operations in response to read, write, and verify requests from the host system. It is assumed that a read error such as an ID read error occurs during this read / write operation.

When a read error occurs, the CPU 4
As shown in FIG. 2, a retry operation is executed. That is, first, a retry counter (internal register) for controlling the number of retry operations is initialized (step S1).
In this initialization, a predetermined maximum number of retry operations is set.

The CPU 4 reads / reads according to the command.
Write and verify operations are executed (step S2).
When a read error occurs again by the first retry operation, the CPU 4 executes a parameter update process for updating the parameter (here, the data strobe offset value) of the read / write circuit 8. First, the retry counter is decremented and a new data strobe offset value is calculated with respect to the initial value (steps S5 to S5).
S7).

The CPU 4 reads a table value (change value) Wtn (n is the number of times) according to the number of retries from the parameter updating table stored in the ROM 5 in advance, and sets the change value Wtn to the current data strobe offset value WC. New data strobe offset value (WC + Wt)
n) is calculated (step S7). Here, the change value Wtn
Is, for example, a nine-step value from -4 to +4.

The CPU 4 sets the calculated new data strobe offset value (WC + Wtn) in the read / write circuit 8 via the parameter setting circuit 8a (step S8). As a result, the data strobe offset value of the read / write circuit 8 is updated.

Next, the CPU 4 executes the read operation, and if the read error does not occur, the calculated new data strobe offset value (WC + Wtn) is set as the optimum value (NO in step S3, S4). At this time, CP
U4 may store the updated optimum data strobe offset value (WC + Wtn) in the memory.

On the other hand, if a further read error occurs, the CPU 4 repeats the above steps S5 to S8. That is, a new data strobe offset value (WC + Wtn) is calculated and set in the read / write circuit 8. Here, when the number of retry operations exceeds the maximum number set in the retry counter, the CPU 4 recognizes that it is impossible to prevent the occurrence of the read error only by changing the parameter, and notifies the host system of the error. (YE in step S5
S, S9). Thereby, for example, an error process for stopping the drive of the HDD is executed.

In this way, when a read error occurs when a read / write or verify operation is executed in response to a command from the host system, the CPU 4 executes a retry operation. At this time, the table is used to execute a parameter updating process for updating the parameters (data strobe offset value, etc.) of the read / write circuit 8.

Further, based on the updated parameters,
If an error recovery state is reached when the retry operation is executed, the parameters updated at the time of error recovery are set in the read / write circuit 8 as optimum values. Therefore, since the retry operation is executed by the parameter of the read / write circuit 8 different from that before the error occurrence, the possibility of error recovery increases. In other words, the frequency of read errors can be reduced.

In this embodiment, it is possible to reduce unnecessary retry operations by setting the maximum number of retry operations based on the change value of the parameter updating table in advance. That is, it is possible to shift to error processing without updating parameters and without wasting time such as performing a retry operation.

[0032]

As described in detail above, according to the present invention, when a read error occurs, the retry operation is executed while updating the parameters of the read / write circuit. Therefore, it is possible to adjust the parameters of the read / write circuit by utilizing the retry operation each time a read error occurs, and consequently set the parameters to the optimum values. This allows
It is possible to realize error recovery early after the occurrence of the read error and reduce the frequency of occurrence of the read error.

[Brief description of drawings]

FIG. 1 is a block diagram showing a main part of an HDD according to an embodiment of the present invention.

FIG. 2 is a flowchart for explaining the operation of the embodiment.

[Explanation of symbols]

1 ... Head, 2 ... Disk, 4 ... CPU, 6 ... HDC,
7 ... Buffer memory, 8 ... Read / write circuit, 9 ... Servo circuit.

Claims (4)

[Claims] 1. A data recording / reproducing apparatus for performing a data read / write operation on a disk by a head, reproducing read data from a read signal read from the disk by the head, and writing according to the write data. A read / write circuit means for executing a read / write process for supplying a signal to the head and externally setting a parameter for determining the read / write characteristics, and an error occurs when the read / write operation is executed by the head. In this case, retry control means for executing the retry operation of the read / write operation up to a predetermined number of times or until error recovery, the parameter is updated at the time of the retry operation, and the parameter updated at the time of error recovery is read / read.
A data recording / reproducing apparatus comprising: a parameter updating unit for setting the write circuit unit. 2. A data recording / reproducing apparatus for performing a data read / write operation on a disk by a head, reproducing read data from a read signal read by the head from the disk, and writing according to the write data. A read / write circuit means for executing a read / write process for supplying a signal to the head and externally setting a parameter for determining the read / write characteristics, and an error occurs when the read / write operation is executed by the head. In this case, a retry control means for executing the retry operation of the read / write operation up to a predetermined number of times or error recovery, and a parameter update table including a plurality of change values for updating the parameter in advance are prepared, and the retry operation is performed. Before changing from the parameter update table for each operation A parameter updating means for reading the change value, calculating a new parameter based on the change value, and setting the new parameter calculated at the time of the error recovery in the read / write circuit means as an updated parameter; A data recording / reproducing apparatus comprising: 3. The data recording according to claim 1, wherein the parameter is a data strobe offset value for determining a peak position of the read signal when reproducing the read data. Playback device. 4. A head for performing a data read / write operation on a disk and read data from a read signal read by the head from the disk, and a write signal corresponding to the write data is supplied to the head. Read / write processing to
In a data recording / reproducing apparatus equipped with a read / write circuit means capable of externally setting a parameter for determining a write characteristic, if an error occurs during a read / write operation by the head, the read / write operation is retried. Performing an operation a predetermined number of times or until error recovery, updating the parameter during the retry operation, and reading / reading the parameter updated during the error recovery
And a step of setting in the write circuit means.