JPH05182382A - Off-track correction method for magnetic disk device - Google Patents

Abstract

PURPOSE:To easily and effectively execute the correction by reading an average off-track correction value of an object cylinder and its direction from a memory at first and correcting them at the off-track correction after seek operation to the object cylinder. CONSTITUTION:When a microcomputer 1 selects an object cylinder correction value, a correction storage memory 2 is addressed to read off-track information and when a correction value of a representative cylinder is selected, a storage section is addressed to read off-track information. A servo controller 3 converts an off-track into a current and an actuator 7 is driven through a power amplifier 4, an arm 8 and a head 9 are moved and he off-track is corrected. A peak detector 5 reads the off-track information of the head 9 on the object cylinder from an off-track correction pattern on a medium 10 and fetches the information to the microcomputer 1 via an A/D converter 6, the firmware is used to process the information thereby correcting the off-track. When read is disable, a seek fault is set and the processing is terminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk device, and more particularly to a magnetic disk device for controlling head positioning in a cylinder on a data area of a disk by firmware using an off-track correction method utilizing a data surface. The present invention relates to the off-track correction method.

[0002]

2. Description of the Related Art In conventional off-track correction by firmware, as shown in FIG. 6, first, a target cylinder value is set and a head is selected (aa in FIG. 6), and a seek is executed (in FIG. 6). ab). Before the off-track correction, the average off-track value and the direction value of the representative cylinder are obtained and set by the get offset command (ac in FIG. 6), and the first off-track correction is executed (a in FIG. 6).
d). After the first off-track correction, the off-track value and the direction value are read from the off-track correction pattern on the disk (ae in FIG. 6), and if the read cannot be performed, a time-out error occurs (af in FIG. 6) and seek fault occurs. Set (ag in FIG. 6) and finish.

When the read is successful, it is confirmed that the read off-track value is within the set value 1 (3 in hexadecimal) (ah in FIG. 6). If it is within the set value 1, the off-track value,
Store the direction value in the RAM of the microcomputer (ai in Fig. 6)
The off-track correction execution is ended (ak in FIG. 6), and if it is outside the set value 1, the off-track value and direction value read from the disc are set (aj in FIG. 6), and the off-track correction is executed again. .. Then, every time the off-track correction is performed, the off-track value and the direction value are read from the off-track correction pattern on the disk, and the off-track value and the direction value are repeatedly executed until the set value becomes 1 or less.

[0004]

In the above-mentioned conventional example, as the first off-track correction value, the average off-track for each head of the representative cylinder obtained from the get-offset command executed before the off-track correction. Since the values and the direction values are used, it is not possible to perform uniform correction on all cylinders having different off-track values and direction values for each cylinder. Moreover, it is necessary to execute the get offset command before the off-track correction. In addition, during the off-track correction after the first off-track correction has failed, there is an inconvenience that it is necessary to make a seek fault or repeat the correction many times for the cylinder on the inner peripheral side, which is difficult to correct. It was

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an off-track correction method for a magnetic disk drive, which is capable of improving the disadvantages of the conventional example and, in particular, capable of easily and effectively executing the off-track correction. To do.

[0006]

According to the present invention, for off-track correction under the control of firmware of a magnetic disk device, all cylinders in a data area of a disk and each cylinder of an average off-track correction value obtained for every head. It has a memory that stores a table for each value and direction value, and reads the average off-track correction value and direction value of the target cylinder from the memory at the beginning of the off-track correction after the seek operation to the target cylinder. The off-track correction is performed by the method. This aims to achieve the above-mentioned object.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a hardware block diagram for executing off-track correction by firmware of the magnetic disk device according to the present embodiment. In FIG. 1, reference numeral 1 is a microcomputer including a program for operating the magnetic disk device including execution of off-track correction. Also,
Reference numeral 2 is a correction value storage memory (RAM with backup power supply) that stores a table of average off-track values and direction values obtained for all cylinders and all heads on the data area of the disk plate 10.

The maincoin 1 drives the address bus of the signal line 1 to store an off-track value and a direction value stored in the correction value storage memory 2 (hereinafter referred to as off-track information).
Is read through the data bus of the signal line 2. Reference numeral 3 is a servo controller which takes in off-track information output from the microcomputer 1 through the signal line 2 and controls the power amplifier 4 in place of the amount of current (voltage). Code 4
Is a power amplifier for driving the actuator 7. The actuator 7 is current-driven according to the off-track information converted into the amount of current to horizontally move the head 9.

The actuator 7 is an interlocking head 9
An arm 8 for supporting a disk and a disk plate 10 for storing data
The head 9 for reading and writing data is driven by the current of the power amplifier 4. The signal line 3 and the signal line 4 are signal lines for transmitting current drive. The peak detector indicated by reference numeral 5 reads the off-track information of the off-track correction pattern written on the medium 10 and converts it into a DC level voltage amount. Reference numeral 6 is an A / D converter for converting the off-track information converted by the peak detector 5 into a digital value, which is usually built in the microcomputer 1. The signal line 5 is a signal line for transmitting the off-track information of the head 9, the signal line 6 is a signal line for transmitting the off-track information as a voltage amount, and the signal line 7 is a signal line for transmitting the off-track information as a digital value to the microcomputer 1.

2 to 5, the off-track correction execution by the firmware of the magnetic disk device of this embodiment will be described with reference to these flowcharts. Before executing off-track correction, set the target cylinder value of the seek destination and select the head (a in Fig. 2).
A seek operation is executed (b in FIG. 2). After execution, head 9
Then, the microcomputer 1 starts the off-track correction execution by the firmware.

The microcomputer 1 determines whether the off-track correction is executed by the correction value of the target cylinder or the correction value of the representative cylinder (c in FIG. 2), and if the correction value of the target cylinder is selected, the correction value is selected. Signal line 1 in storage memory 2
The address where the off-track information of the target cylinder is stored is addressed, the off-track information is read through the signal line 2 (e in FIG. 2), and the correction value of the representative cylinder is selected. 2 is addressed through the signal line 1 to the portion where the off-track information of the representative cylinder is stored, and the off-track information is read through the signal line 2 (d in FIG. 2).

The read off-track information is transmitted to the servo controller 3 through the signal line 2. The servo controller 3 converts the off-track information into a current amount (voltage amount) and transmits it to the power amplifier 4 through the signal line 3. The power amplifier 4 drives the actuator 7 through the signal line 4 by the amount of the transmitted current, that is, the off-track information. By driving the actuator 7,
The interlocked arm 8 and head 9 move to perform off-track correction (f in FIG. 2).

On the other hand, the peak detector 5 reads the off-track information of the head 9 on the target cylinder through the signal line 5 from the off-track correction pattern written on the medium 10 (g in FIG. 2), It is converted into a DC level voltage amount and taken into the A / D converter 6 through the signal line 6. When the off-track information cannot be read and a time-out error occurs (h in FIG. 2), the seek fault is set (i in FIG. 2) and the process ends. A / D converter 6
Converts the read voltage amount of off-track information into a digital value and takes it into the microcomputer 1 through the signal line 7. The value fetched by the microcomputer 1 is processed on the firmware.

The processing on the firmware will be described below. If the read off-track value is equal to or greater than the maximum setting value (a number close to the off-track for half a cylinder),
To jump to the off-track fault counter (the RAM value of the microcomputer 1 set by the large off-track value) (r in FIG. 4),
The off-track fault counter value is the set value 3 (1-
9 (arbitrary number of 9) (s in FIG. 4), the positioning is considered to be defective and the process ends (t in FIG. 4). If not, rezero seek (seek to 0 cylinder) is executed (u in FIG. 4), the process returns to and the target cylinder is again sought and off-track correction is executed. If the read off-track value is within the set value 2, then it is checked whether the off-track value is within the minimum set value 1 (3 in hexadecimal).
If it is within the range, the off-track value and the direction value at that time are stored as new values in the correction value storage memory 2 (1 in FIG. 2),
The off-track correction is finished (m in FIG. 2).

If the off-track value does not fall within the set value 1, the off-track correction execution counter (the RAM value of the microcomputer 1 which stores the number of times of execution of the off-track correction) is incremented, and the off-track correction execution counter value is set to the set value. If it is within 4 (an arbitrary number of 5 or more) (o in FIG. 3), the execution counter over flag (the RAM of the microcomputer 1 set at t in the figure when the number of executions of the off-track correction exceeds the set value 4) Value) is set (p in FIG. 3), and if not set, the off-track value and the direction value are set (q in FIG. 3), and the process returns to and the off-track correction is executed again. To do. When the off-track correction execution counter exceeds the set value 4, the execution counter over flag is set (v in FIG. 5), the off-track correction execution counter value is cleared (w in FIG. 5), and the read off-track value After setting the off-track correction value of μ times (μ value is an arbitrary number less than decimal) (x in FIG. 5),
Return to and execute off-track correction.

After the correction, if the off-track value does not fall within the set value 1 (k in FIG. 2), the execution counter over flag is set. Therefore, the off-track value read from the n in FIG. The off-track correction value that is μ times the value is set and the procedure returns to, and the off-track correction is repeated until the off-track value falls within the set value 1. The above is one embodiment of the off-track correction by the firmware of the magnetic disk device of the present invention.

[0017]

As described above, according to the present invention,
By having a memory storing a table of data and direction data for each cylinder of the average off-track value obtained for all heads, without issuing a get-offset command to obtain the off-track information of the representative cylinder, The off-track value that matches the off-track information of the target cylinder or can be easily and quickly executed from the off-track information of the representative cylinder, and the off-track value read from the disk when the first off-track correction fails Even if it is difficult to correct, it increases the certainty of off-track correction by performing re-zero seek and retry seek to the target cylinder, or changing off-track correction value to execute off-track correction. Off-track correction for magnetic disk drive The law can be provided.

[Brief description of drawings]

FIG. 1 is a control block diagram at the time of off-track correction of a head of a magnetic disk device showing an embodiment of the present invention.

2 to 5 are flowcharts showing an off-track correction execution state by firmware of the magnetic disk device in the embodiment shown in FIG.

FIG. 6 is a flowchart showing a conventional example.

[Explanation of symbols]

 1 Microcomputer 2 Correction Value Storage Memory 3 Servo Controller 4 Power Amplifier 5 Peak Detector 6 A / D Converter 7 Actuator 8 Arm 9 Head 10 Disk Board

Claims (4)

[Claims] 1. An off-track correction under the control of firmware of a magnetic disk device, a value for each cylinder of an average off-track correction value obtained for all cylinders and all heads in a data area of a disk, and a direction value It has a memory that stores a table, and executes the off-track correction by first reading the average off-track correction value and the direction value of the target cylinder from the memory at the time of the off-track correction after the seek operation to the target cylinder. An off-track correction method for a magnetic disk device characterized by the above. 2. The off-track correction is executed based on the average off-track correction value and the direction value of the representative cylinder that are read from the memory at the beginning of the off-track correction. Off-track correction method for magnetic disk drive of the present invention. 3. The magnetic disk drive according to claim 1, wherein when the first off-track correction fails, the retry is performed according to the magnitude of the off-track correction value read from the disk. Track correction method. 4. If the first off-track correction fails, the off-track correction value is changed and the correction is executed according to the number of times of execution of the off-track correction read from the disk. Item 2. An off-track correction method for a magnetic disk device according to Item 1.