JPH04301260A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To provide a hard disk device in which the data of the sector of abnormal sector information can be updated as necessary in the magnetic disk device of a sector servo system. CONSTITUTION:An abnormality detection circuit 5 detects the presence of the abnormality of servo data. When the abnormality detection circuit 5 detects the abnormality of the servo data, a magnetic disk device inhibits the write-in of the data to a magnetic disk in a normal mode. On the other hand, when a special mode is set by a mode setting circuit 7, the magnetic disk device makes it possible to write the data to the magnetic disk irrespective of the presence of the abnormality of the servo data.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sector servo type magnetic disk device.

0002

2. Description of the Related Art In order to protect data, a conventional sector servo type magnetic disk device prohibits data from being written to that sector when an abnormality in servo data is detected. Furthermore, if the cylinder address information in the servo data is abnormal due to a media defect or the like, it is determined that the head positioning is not normal and writing to the desk is prohibited.

0003

Problems to be Solved by the Invention In conventional hard disk devices, there is a problem in that writing of data to a sector in which a defect exists is uniformly prohibited, and defect replacement processing is impossible. Therefore, when an abnormality occurs in the servo data while using the magnetic disk due to the growth of a defect, the format of the sector where the defect occurs cannot be updated, and the previously created data remains. . As a result, two sectors with the same ID information are created,
If a sector pulse occurs for some reason, there is a risk of reading incorrect data.

The present invention has been made in view of the above circumstances, and an object of the present invention is to, when an abnormality occurs in servo data, transfer data to the sector where the abnormality is detected as necessary. An object of the present invention is to provide a magnetic desk device that can be written on.

Another object of the present invention is to provide a magnetic disk device that allows the user to reformat the magnetic disk when an abnormality occurs in servo data.

[0006]

[Means for Solving the Problems] In order to achieve the above object, a sector servo type magnetic desk device according to a first aspect of the present invention includes an abnormality detection means for detecting an abnormality in servo data, and an abnormality detection means in which the abnormality detection means is configured to detect an abnormality in servo data. a prohibition means for prohibiting data writing to the magnetic disk when an abnormality in the servo data is detected; a mode setting means; A means is provided to enable data to be written to the magnetic disk.

[0007] In order to achieve the above object, the second aspect of the present invention
In the magnetic disk device according to the above aspect, when an abnormality is detected in the servo data of a certain sector, a special mode is instructed and the head positioning is normal in the magnetic disk device that prohibits data writing to the sector. When it is determined that there is an abnormality, data can be written to the magnetic disk regardless of whether there is an abnormality in the servo data.

[0008]

[Operation] In the magnetic disk device having the above configuration, when an abnormality in servo data is detected, writing of data to the magnetic disk is normally prohibited. Therefore, writing data to the abnormal sector is prohibited, and the data is protected. on the other hand,
When the special mode is set, data can be written to the magnetic disk regardless of whether there is an abnormality in the servo data. Therefore, data can be written to a sector in which servo data is abnormal, and the data format etc. can be updated.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A magnetic desk apparatus according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the circuit configuration (only the portions related to the present invention) of the magnetic desk device according to this embodiment.

In FIG. 1, signals read by a magnetic head 1 are supplied to a read/write amplifier 2. As shown in FIG. The amplifier 2 amplifies the read signal and also amplifies and supplies the write signal to the magnetic head 1. Further, the amplifier 2 includes a write abnormality detection circuit, and outputs a head unsafe signal US when a write abnormality occurs.

A read signal RS from the amplifier 2 is supplied to a sector pulse detection circuit 3. Generally, servo data has a structure shown in FIG. 2(A). When the sector pulse detection circuit 3 detects a predetermined sector pattern included in the servo data of the read signal RS supplied from the amplifier 2, it outputs the sector pulse shown in FIG. 2(B).

The output signal of the sector pulse detection circuit 3 is supplied to a write permission area signal generation circuit 4. In response to the sector pulse from the sector pulse detection circuit 3, the write permission area signal generation circuit 4 maintains a low state during the period when the magnetic head 1 is located above the servo area of the magnetic disk, as shown in FIG. A write permission area signal that is at a high level while the magnetic head 1 is located on the data area is output.

The read signal RS from the amplifier 2 is also supplied to the abnormality detection circuit 5. The abnormality detection circuit 5 checks whether or not there is an abnormality in the servo data included in the read signal RS, and outputs a low level signal if an abnormality is detected. An abnormality in servo data means, for example, an abnormality in cylinder address information, an abnormality in a position burst signal, or the like.

The output signals of the write permission area signal generation circuit 4 and the abnormality detection circuit 5 are supplied to an AND circuit 6. The AND circuit 6 outputs a high level signal when both input signals are at a high level, that is, when the servo data is normal and the magnetic head 1 is located on the write permission area.

The mode setting circuit 7 is composed of a switch and the like, and switches between a normal mode (a mode that prohibits data writing to an abnormal sector) and a special mode (a mode that allows data writing to an abnormal sector). Outputs a low level signal when specifying normal mode, and outputs a high level signal when specifying special mode.

The output signals of the AND circuit 6 and the mode setting circuit 7 are supplied to an OR circuit 8. The OR circuit 8 outputs a high level signal when at least one of the output signals of the AND circuit 6 and the mode setting circuit 7 is at a high level. That is, the OR circuit 8 outputs a high level signal when the servo data is normal and the magnetic head 1 is located on the write permission area, or when the special mode is set.

The read signal RS from the amplifier 2 is also supplied to the servo control circuit 9. The servo control circuit 9 controls the position of the magnetic head 1 based on servo data. The servo control circuit 9 outputs a high level signal when the positioning of the magnetic head 1 is normal.

The output signal of the servo control circuit 9 and the head unsafe signal U from the head abnormality detection circuit of the amplifier 2
S is supplied to the OR circuit 10. The OR circuit 10 outputs a high level signal when at least one of the input signals is at a high level, that is, when the positioning of the magnetic head 1 is abnormal or when a write abnormality occurs.

The controller (HDC) 11 is supplied with various control signals from the host system, and controls the entire hard disk device shown in FIG. 1 based on these control signals. H
When writing data, the DC 11 supplies a write instruction signal (write gate signal) WG to the gate circuit 12, and writes the write data W.
D is supplied to the write circuit 13.

The gate circuit 12 receives the output signals of the OR circuits 8 and 10 and the write instruction signal WG from the HDC 11, and receives the write instruction signal WG from the HDC 11 when the output signals of the OR circuits 8 and 10 are both at high level. WG is supplied to the write circuit 13, and a low level write fault signal WF is supplied to the HDC 11. The gate circuit 12 is an OR circuit 8
When at least one of the output signals 1 and 10 is at a high level, the supply of the write instruction signal WG from the HDC 11 to the write circuit 13 is stopped, and at the same time, a high level write fault signal WF is supplied to the HDC 11.

The write circuit 13 supplies the write data WD supplied from the HDC 11 to the amplifier 2 in response to the write instruction signal WG supplied from the gate circuit 12, and writes data to the magnetic disk. Next, the operation of the sector servo type magnetic disk device having the above configuration will be explained. (1) First, the operation when the servo data is normal will be explained.

When the servo data shown in FIG. 2(A) is normal, the sector pulse detection circuit 3 detects the sector pattern included in the servo data and outputs the sector pulse shown in FIG. 2(B). In response to this sector pulse,
The write permission area signal generation circuit 4 outputs the write permission area signal shown in FIG. 2(C).

Since the abnormality detection circuit 5 does not detect any abnormality in the servo data, it continues to output a high level signal. The two inputs of the AND circuit 6 both become high level, and the AND circuit 6
outputs a high level signal. Due to the high level signal from the AND circuit 6, the OR circuit 8 is activated by the mode setting circuit 7.
Outputs a high level signal regardless of the setting.

In response to the high level signal from the OR circuit 8, the gate circuit 12 controls the HDC 11 when the output of the OR circuit 10 is at a low level, that is, when the head positioning is normal and no writing abnormality has occurred. A write instruction signal WG supplied from the write circuit 13 is supplied to the write circuit 13, and a low-level write false signal WF is supplied to the HDC 11. HDC11
responds to the low-level write false signal WF, supplies the write data WD to the write circuit 13, and writes the write data WD to the magnetic disk.

On the other hand, even when the servo data is normal (that is, the output of the OR circuit 8 is at a high level), the gate circuit 12 detects that the output of the OR circuit 10 is at a low level (that is, the positioning of the magnetic head 1 is abnormal). (or a write abnormality has occurred), the write enable signal is not output, and a high-level write fault signal is supplied to the HDC 11. As a result, H
The DC 11 can detect that writing has failed, and no data is written to the magnetic disk. (2) Next, consider a case where the servo data is abnormal.

[0026] If no sector pattern is detected in the servo data, the sector pulse detection circuit 3 does not output a servo pulse. Therefore, the write permission area signal generation circuit 4 maintains the low level while the magnetic head 1 is located on the sector. Furthermore, when the abnormality detection circuit 5 detects an abnormality in the cylinder address information and/or an abnormality in the position burst signal, it outputs a low level signal.

Therefore, the AND circuit 6 outputs a low level signal when at least one of the sector pattern, cylinder address information, and position burst signal in the servo data is abnormal. Due to the low level signal from the AND circuit 6, the OR circuit 8 continues to output a low level signal unless the mode setting circuit 7 sets the special mode.

Therefore, when the mode setting circuit 7 has set the normal mode, the output of the OR circuit 8 is at a low level. Therefore, the gate circuit 12 supplies the write fault signal WF to the HDC 11 without outputting the write signal. That is, writing data to the abnormal sector is prohibited.

On the other hand, when the mode setting circuit 7 sets the special mode, the output of the mode setting circuit 7 becomes high level, and the output of the OR circuit 8 becomes high level regardless of the output of the AND circuit 6. Therefore, if the output of the OR circuit 10 is at a low level, the gate circuit 12 detects that the head positioning is normal and the head unsafe signal US
When is at a low level, the write instruction signal WG supplied from the HDC 11 is supplied to the write circuit 13. In response to the write instruction signal WG, the write circuit 13 supplies the write data WD supplied from the HDC 11 to the amplifier 2, and writes the write data WD to the magnetic disk.

In this way, if the mode setting circuit 7 is set to the special mode, even if an abnormality occurs in the servo data, if the positioning is normal and no write error occurs,
The data in that sector can be updated, and defect replacement processing becomes possible.

Next, an example of a specific configuration of the abnormality detection circuit shown in FIG. 1 will be explained with reference to FIG. 3. In the circuit of FIG. 3, the abnormality detection circuit 5 and the servo control circuit 9 of FIG. 1 share a part of the circuit. In addition, in FIG. 3, the same parts as in FIG. 1 are given the same reference numerals, and the description thereof will be omitted.

Servo data from the amplifier 2 is supplied to the cylinder control circuit 51. Further, the output of the sector pulse detection circuit 3 is supplied to a servo timing circuit 52. The servo timing circuit 52 detects the timing at which cylinder information (address) is output based on the sector pulse supplied from the sector pulse detection circuit 3 and instructs the cylinder control circuit 51 to detect the timing at which cylinder information (address) is output. The cylinder control circuit 51 checks the cylinder information included in the servo data according to instructions from the servo timing circuit 52, outputs the cylinder information, and detects an abnormality in the cylinder information. The cylinder control circuit 51 outputs a cylinder abnormality signal when the cylinder information is abnormal.

[0033] The servo control circuit 9 is a CP dedicated to servo control.
Equipped with U91. The CPU 91 receives the servo data and sector pulses, checks whether there is an abnormality in the burst signal, and outputs a burst abnormality signal if there is an abnormality. Further, the CPU 91 controls the position of the magnetic head 1 based on cylinder information from the cylinder control circuit 51, and outputs a signal indicating that the magnetic head 1 is currently seeking, offset, etc.

The OR circuit 53 determines the OR of the burst abnormality signal from the CPU 91 and the cylinder abnormality signal from the cylinder control circuit 51. The output of this OR circuit 53 functions as the output of the abnormality detection circuit 5.

The present invention is not limited to the above embodiments, and various modifications are possible. For example, the circuit configurations shown in FIGS. 1 and 3 are not limited to these, and the configuration of servo data is also not limited to the configuration shown in FIG. 2(A).

[0036]

According to the present invention, in a sector servo type magnetic disk device, when sector information is abnormal, the data of the sector can be updated as necessary.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the circuit configuration of a magnetic desk device according to an embodiment of the present invention.

FIG. 2(A) is a diagram showing an example of the structure of servo data. 2(B) and 2(C) are timing charts for explaining the operation of the magnetic desk device shown in FIG. 1. FIG.

FIG. 3 is a block diagram showing an example of the circuit configuration of the abnormality detection circuit shown in FIG. 1;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1... Magnetic head, 2... Amplifier, 3... Sector pulse detection circuit, 4... Write permission area signal generation circuit, 5... Abnormality detection circuit, 6... AND circuit, 7... Mode setting circuit, 8, 10,
53...OR circuit, 11...HDC, 12...gate circuit, 1
3...Writing circuit, 51...Cylinder control circuit, 52...Servo timing circuit, 91...CPU.

Claims (2)

[Claims] 1. A sector servo type magnetic disk device, comprising: an abnormality detecting means for detecting an abnormality in servo data; and when the abnormality detecting means detects an abnormality in the servo data, writing data to the magnetic disk. means for prohibiting, mode setting means for setting a special mode, and when the special mode is set by the mode setting means, data can be written to the magnetic disk regardless of whether or not there is an abnormality in the servo data. Under normal conditions, writing of data to a sector in which the servo data is abnormal is prohibited, while when a special mode is set, writing of data to the sector is prohibited regardless of whether or not there is an abnormality in the servo data. A magnetic desk device that allows 2. When an abnormality is detected in the servo data of a certain sector, a special mode is instructed in a magnetic disk device that prohibits data writing to the sector, and it is determined that the head positioning is normal. 1. A magnetic disk device characterized in that data can be written to a magnetic disk regardless of whether or not there is an abnormality in servo data.