JPH08115578A - Magnetic disk device - Google Patents

Abstract

PURPOSE: To reduce the read-out waiting time of servo data without being accompanied with the increase of the scale of a servo data processing circuit. CONSTITUTION: The simultaneous detection of the servo data by magnetic heads 103a, 103b is eliminated by writing the servo data into recording medium surfaces of the magnetic disks 101, 102 so that the read-out timings of the servo data 104a, 104b are differed from each other between these recording medium surfaces. Then, the servo data read out by the magnetic heads 103a, 103b are selectively transmitted to the servo data processing circuit 111 by a multiplexer 110. Thus, the fetching efficiency of the servo data is improved, and further, the reduction of the waiting time for read-out of servo data is contrived.

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 further relates to a technique for taking in servo data written on the surface of a recording medium for detecting the track position on the surface of the recording medium. Related to effective technology.

[0002]

2. Description of the Related Art A hard disk device is a device in which a combination of a magnetic disk, which is a recording medium, and a head assembly is fixed, and the disk unit and the disk assembly are sealed from the outside air to prevent dust. Intrusion is prevented. When the disk is stationary, the head contacts a dedicated track called the shepping zone,
The magnetic head floats as the rotation of the disk increases, and a so-called contact stop start operation is performed. In such a magnetic disk device, writing of information to a magnetic disk which is a recording medium and reading of information from the magnetic disk are performed via a magnetic head. The magnetic head includes a read amplifier including a write amplifier for writing and a read amplifier for reading.
The light IC is coupled. Positioning of the magnetic head on the target track is performed by a closed loop servo system including a head actuator and a positioning circuit. To enable high-speed and high-accuracy positioning,
Speed control is performed until the vehicle approaches the target track, and position control is performed after the vehicle approaches the target track. For position detection, a track following type is used in which a magnetic disk surface called a servo surface is used for track position detection.

FIG. 3 shows a magnetic head positioning system in a conventional hard disk drive.

Magnetic disks 201 and 202 are rotatably supported, and magnetic heads 203a and 203b are provided corresponding to the magnetic disks 201 and 202. The magnetic heads 20 are attached to the magnetic disks 201 and 202.
Servo data 204 for positioning 3a and 203b
a and 204b are recorded. Magnetic head 204a,
The movement of 204b is performed by the head actuator 206. The head actuator 206 is provided with read amplifiers 207a and 207b and a multiplexer 208 for selecting an output signal of the read amplifiers 207a and 207b based on a head select signal.
The signal selected by the multiplexer 208 is processed by the servo data processing circuit 209, and the head actuator 206 is controlled based on the processing result, so that the magnetic head position can be corrected.

As an example of a document describing the detection of servo data by a magnetic head, "Nikkei Electronics 1985.2.25" issued by Nikkei BP Co., Ltd.
(Pages 181 to 182) ”.

[0006]

In the above conventional hard disk device, since the recording positions of the servo data 204a and 204b on the magnetic disks 201 and 202 are the same, the servo data 204a and 204b are respectively recorded on the magnetic heads 203a and 203b. Can be detected at the same time. However, since the servo data processing circuit is one system, the servo data detected by the magnetic heads 203a and 203b cannot be processed simultaneously. In other words, the servo data processing is
Only those selected by the selecting operation of the multiplexer 208 based on the head select signal are set. For example,
When the output signal of the read amplifier 207a is selected by the multiplexer 208 and the magnetic disk 201 is the access target, only the servo data of this magnetic disk 201 is the processing target, and the servo data of the other magnetic disk 202 is the processing target. Not taken A plurality of servo data processing circuits 209 are provided corresponding to the read amplifiers 207a and 207b.
If the output signal of b is processed individually, the servo data of the magnetic disks 201 and 202 can be efficiently captured in parallel and processed. Then, the servo data processing circuit corresponds to the magnetic head. Moreover, since a plurality of systems are required, the circuit scale becomes large, which is not preferable in a hard disk device that requires a particularly small size. In the hard disk device, rapid detection of servo data and its processing are effective in positioning the magnetic head to the target track promptly, which is effective in shortening the access time of the hard disk device. It is desired to improve the servo data acquisition system.

An object of the present invention is to provide a technique for shortening the servo data read waiting time without increasing the scale of the servo data processing circuit.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0009]

The outline of the representative one of the inventions disclosed in the present application will be briefly described as follows.

That is, in the magnetic disk device, the servo data is written on the recording medium surface so that the reading timing of the servo data is different among the plural recording medium surfaces, and the servo data read by the magnetic head is selected. A selection means for transmitting the data to the servo data processing circuit is provided. At this time, comparison means for comparing the detection results of the plurality of magnetic heads may be provided, and the selection operation of the selection means may be controlled based on the comparison results of the comparison means. Further, a plurality of amplifying means are provided corresponding to the plurality of magnetic heads,
Further, a plurality of conversion means for converting the differential output signal of the amplification means into a single end signal is provided corresponding to the plurality of amplification means, and the single end signals output from the plurality of conversion means are the comparison means. Can be configured to be compared with.

[0011]

According to the above-mentioned means, the servo data is written on the recording medium surface so that the reading timings of the servo data are different among the plural recording medium surfaces. Eliminate detection.
Then, the selecting means enables the servo data detected by the magnetic head to be selectively transmitted sequentially to the servo data processing circuit of one system. This achieves an improvement in the efficiency of capturing servo data on a plurality of recording medium surfaces and a reduction in the servo data read wait time without increasing the scale of the servo data processing circuit.

[0012]

FIG. 2 shows the overall construction of a hard disk drive according to an embodiment of the present invention.

A hard disk device (also called a fixed disk device) is a magnetic disk device used as an external storage device of a type in which a combination of a disk unit as a storage medium and a head assembly is fixed. To be done.

Although not shown in FIG. 2, in a hard disk device, a disk-shaped recording medium (magnetic disk) is used.
Is provided, and writing / reading of information to / from this recording medium is performed via the magnetic heads 103a and 103b. The magnetic heads 103a and 103b are not particularly limited, but cores made of MnZn ferrite are applied. Start / stop is performed with the magnetic head in contact with the head disk surface.
When the disk reaches constant speed rotation, the air flow causes the magnetic head to float above the disk surface of 0.4 to 1.5 μm, forming a gap between the magnetic head and the disk surface. The head assembly is tightly sealed because fine dust in such a gap causes a head crash. The magnetic heads 103a and 103b are coupled to the read / write circuit 50. The read / write circuit 50 includes a read / write amplifier 114 provided for the magnetic heads 103a and 103b, a head selection circuit 52 for switching heads, an amplifier circuit 53, a flip-flop 54, and the like, but is not particularly limited. It is formed on one semiconductor substrate such as a single crystal silicon substrate by a known semiconductor integrated circuit manufacturing technique. Such a read / write circuit 50
In order to reduce the influence of noise, the magnetic heads 103a, 10a
The arm member supporting 3b is arranged in the vicinity of the magnetic head and is connected to the main board 60 by various signal lines. The main board 60 has a controller 55 for controlling the entire apparatus of this embodiment and the magnetic disk 1.
03a, 103b, signal processing circuit 56 for processing write signals and read signals, magnetic heads 103a, 10
Servo data processing circuit 111 for performing servo data processing for positioning 3b, and this servo data processing circuit 11
1 based on the processed output signal of
A head actuator control circuit 112 and the like for controlling the operation of No. 13 are mounted. The controller 5
5 is constituted by a microcomputer or the like.
In the signal processing circuit 56, the binary data for writing is modulated according to a predetermined recording method. On the other hand, at the time of reading data, peak detection processing is performed on the output signal from the amplifier circuit 53, and timing pulse and data separation processing is performed by demodulation.

The read / write amplifier 114 includes read amplifiers 105a and 105b provided corresponding to the magnetic heads 103a and 103b and write amplifiers 106a and 106a.
b is included. The read information from the magnetic heads 103a and 103b is amplified by the corresponding read amplifiers 105a and 105b. The magnetic head 1
03a and 103b include corresponding write amplifiers 106
A write current is supplied via a and 106b. The output signals of the read amplifiers 105a and 105b are amplified by the amplifier circuit 53 arranged in the subsequent stage and then transmitted to the signal processing circuit 56 of the main board 60. The write data from the signal processing circuit 56 is transmitted to the write amplifiers 106a and 106b via the flip-flop 54 and the head selection circuit 52.

The positioning of the magnetic heads 103a and 103b on the target track is performed by the head actuator 113 or
This is performed by a magnetic head positioning system formed by a servo data processing circuit 111, a head actuator control circuit 112, and the like. In this embodiment, this magnetic head positioning system uses the servo data of the recording medium surface for track position detection. Followed.

FIG. 1 shows a magnetic head positioning system in the apparatus of this embodiment.

Although not particularly limited, magnetic disks 101 and 102 formed by mixing acicular magnetic particles with a binder and coating the mixture on a disc-shaped aluminum alloy substrate are rotatably supported by the magnetic disk. Magnetic heads 103a and 103b are provided corresponding to the disks 101 and 102. Although not particularly limited, the magnetic disks 101 and 102 are designed to be rotationally driven by an induction motor or the like, and such magnetic disks 101 and 102 include:
Servo data 104a and 104b for positioning the magnetic heads 103a and 103b on the target track are recorded. A plurality of servo data 104a and 104b are recorded on all tracks of the magnetic disks 101 and 102, respectively, at predetermined intervals. In this embodiment, the servo data 104a and 104b are written such that the read timings of the servo data are different between the recording surfaces of the magnetic disks 101 and 102 which are recording media. That is, according to the conventional technique, as shown in FIG. 3, since the recording positions of the servo data 204a and 204b are the same on the magnetic disks 201 and 202, the servo data 204a and 204b are respectively recorded on the magnetic heads 203a and 203b. Although it is detected by 203b at the same time, in the apparatus of this embodiment, as shown in FIG. 1, the recording position of the servo data is formed between the magnetic disks 101 and 102 while being displaced in the disk rotation direction. As a result, the servo data is alternately detected by the magnetic heads 103a and 103b.

The magnetic heads 104a and 104b are also provided.
Is moved by the head actuator 113. The head actuator 113 includes a read / write amplifier 1 coupled to the magnetic heads 103a and 103b.
14 are provided. Magnetic heads 103a and 103b
Is detected by the read amplifier 105 as an amplifying means.
After being respectively amplified by a and 105b, they are transmitted to the servo data fetch circuit 109 in the subsequent stage.

The servo data acquisition circuit 109 includes conversion amplifiers 107a and 107b as conversion means for converting the differential output signals of the read amplifiers 105a and 105b into single-ended signals, and the conversion amplifier 107.
The voltage comparison circuit 108 as a comparison means for comparing the output voltage levels of a and 107b, and this voltage comparison circuit 1
The read amplifiers 105a, 1a based on the output signal of 08.
And a multiplexer 110 as a selection means for selectively transmitting the output signal of 05b to the servo data processing circuit 111 in the subsequent stage. Since the recording positions of the servo data are formed to be displaced in the disk rotation direction, the servo data is alternately detected by the magnetic heads 103a and 103b. For example, when the servo data 104a is detected by the magnetic head 103a, No servo data is detected by the magnetic head 103b. for that reason,
In the voltage comparison in the voltage comparison circuit 108, the level of the output voltage of the conversion amplifier 107a becomes higher than the output voltage of the conversion amplifier 107b, which causes the plexer 110 to operate.
Selects the output signal of the read amplifier 105a and transmits it to the servo data processing circuit 106. The servo data processing circuit 111 holds the full-wave rectified output signal of the signal transmitted through the multiplexer 110 and the full-wave rectified output signal. Then, the head actuator control circuit 112 controls the operation of the head actuator 113 based on the held signal. By controlling the head actuator 113, the magnetic head is positioned on the target track based on the detection of the servo data.

Similarly, when the servo data 104b is detected by the magnetic head 103b, the magnetic head 103b is detected.
In the voltage comparison in the voltage comparison circuit 108, the level of the output voltage of the conversion amplifier 107b becomes higher than the output voltage of the conversion amplifier 107a because the servo data is not detected in a. The output signal of
It is transmitted to the servo data processing circuit 111 in the subsequent stage. In this way, the magnetic heads 103a and 103b alternately detect the servo data of the magnetic disks 101 and 102, and the servo data is transmitted to the servo data processing circuit 111 via the multiplexer 110. Then, the magnetic disks 101, 102
Servo data are processed in parallel. so,
Servo data 104a of the magnetic disks 101 and 102,
By efficiently capturing 104b in the servo data processing circuit 111, the waiting time for reading the servo data can be shortened. That is, in this embodiment,
The waiting time for reading the servo data is 1 / (number of recording medium surfaces) as compared with the conventional device shown in FIG. For example, when the number of recording medium surfaces is 2, the servo data read waiting time is shortened to 1/2, and when the recording medium surface number is 4, the servo data read waiting time is shortened to 1/4. To be done. As described above, the larger the number of recording medium surfaces, in other words, the larger the number of magnetic disks, the shorter the waiting time for reading the servo data.

The output signal of the voltage comparison circuit 108 is supplied to the controller 55 on the main board. This controller 55 is connected to the voltage comparison circuit 108.
It is possible to recognize which recording medium surface the currently fetched servo data belongs to based on the output signal of, and thereby to determine the magnetic head to be driven by the actuator. There is.

According to the above embodiment, the following operational effects can be obtained.

(1) The magnetic head 103 is written by writing servo data on the recording medium surfaces of the magnetic disks 101 and 102 so that the reading timings of the servo data 104a and 104b are different between the recording medium surfaces.
Simultaneous detection of servo data by a and 103b is eliminated, and the servo data read by the magnetic heads 103a and 103b is selectively servo data processing circuit 111 by a multiplexer 110 as selection means.
Therefore, it is possible to improve the efficiency of fetching the servo data and thereby shorten the waiting time for reading the servo data. Since the waiting time for reading the servo data is shortened as described above, the magnetic head can be quickly positioned on the target track, so that the access time of the hard disk device can be shortened. Moreover, the servo data processing circuit 111
Since only one system is required as in the case of the conventional device, the servo data read circuit wait time can be shortened without increasing the circuit scale of the servo data processing circuit 111.

(2) Multiple magnetic heads 103a, 103
The voltage comparison circuit 108 is provided as a comparison means for comparing the detection results of b, and the selection operation of the multiplexer 110 is controlled based on the comparison result of the voltage comparison circuit 108. Head 1
It is possible to accurately control the selection operation of the multiplexer 110 according to the servo data detection by 03a and 103b.

(3) Read amplifiers 105a and 105b as amplifying means for amplifying the detection signals from the magnetic heads 103a and 103b, and the read amplifier 105.
Conversion amplifier 107 as a plurality of conversion means for converting the differential output signals of a and 105b into a single end signal
a and 107b are provided, and the conversion amplifiers 107a, 107a,
Since the single end signal output from 107b is configured to be compared by the voltage comparison circuit 108, the voltage comparison circuit 108 can accurately perform the voltage comparison.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited thereto, and it goes without saying that various modifications can be made without departing from the scope of the invention. Yes.

For example, in the above-mentioned embodiment, the one having two magnetic disks 101 and 102 has been described, but three or more magnetic disks can be provided. Further, in the above embodiment, one magnetic disk has one recording medium surface formed, but in an actual hard disk device, both surfaces of one magnetic disk are often used as the recording medium surface. The present invention can be applied to such a case. Further, in the above embodiment, the servo data acquisition circuit 109 is replaced by the read / write circuit 5.
However, the servo data fetch circuit 109 may be mounted on the main board 60 together with the servo data processing circuit 111. In the above embodiment, the description has been given of the case where the voltage level comparison circuit 108 for comparing the voltage levels is provided, but instead of the voltage level comparison circuit 108, the conversion amplifier 107.
A / D converter for converting the output voltage of a, 107b into a digital signal is provided, and the output value of the A / D converter is compared by a microcomputer or the like forming the controller 55 shown in FIG. The operation of the multiplexer 110 may be controlled based on the comparison result.

In the above description, the case where the invention made by the present inventor is mainly applied to the hard disk drive which is the field of application which is the background of the invention has been described. However, the present invention is not limited to this and random information is used. It can be widely applied to magnetic disk devices that enable access.

The present invention can be applied on condition that it includes at least a plurality of recording medium surfaces.

[0031]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.

That is, the servo data is written on the recording medium surface so that the read timings of the servo data are different among the plural recording medium surfaces, thereby eliminating the simultaneous detection of the servo data by the plurality of magnetic heads. Then, the servo data read by the magnetic head is
Since it is selectively transmitted to the servo data processing circuit by the selection means, it is possible to improve the efficiency of capturing servo data on a plurality of recording medium surfaces without increasing the scale of the servo data processing circuit. The waiting time for reading servo data can be shortened. Since the waiting time for reading the servo data is shortened as described above, the magnetic head can be quickly positioned on the target track, so that the access time can be shortened.

[Brief description of drawings]

FIG. 1 is a block diagram of a configuration example of a magnetic head positioning system in a hard disk device that is an embodiment of the present invention.

FIG. 2 is a block diagram of a configuration example of a writing / reading system in the hard disk device.

FIG. 3 is a block diagram of a configuration example of a magnetic head positioning system in a conventional hard disk device.

[Explanation of symbols]

 50 read / write circuit 52 head selection circuit 53 amplification circuit 54 flip-flop 55 controller 56 signal processing circuit 101, 102 magnetic disk 103a, 103b magnetic head 104a, 104b servo data 107a, 107b conversion amplifier 108 voltage comparison circuit 109 servo data acquisition circuit 110 Multiplexer 111 Servo data processing circuit 112 Head actuator control circuit 113 Head actuator 114 Read / write amplifier

Claims (3)

[Claims] 1. A plurality of recording medium surfaces, and servo data written on the recording medium surfaces for detecting track positions of the recording medium surfaces, which are provided corresponding to the plurality of recording medium surfaces, can be read. In a magnetic disk device including a magnetic head and a servo data processing circuit for processing servo data read by the magnetic head, the servo data read timings are different between the plurality of recording medium surfaces, A magnetic disk device comprising servo data written on the surface of the recording medium, and selection means for selectively transmitting the servo data read by the magnetic head to the servo data processing circuit. 2. A comparison means for comparing the detection results of the plurality of magnetic heads, wherein the selection operation of the selection means is controlled based on the comparison result of the comparison means. The magnetic disk device described. 3. A plurality of amplifying means provided corresponding to the plurality of magnetic heads for amplifying a detection signal by the corresponding magnetic heads, and corresponding amplifying means provided corresponding to the plurality of amplifying means. A plurality of conversion means for converting the differential output signal of the means into a single end signal, and the levels of the single end signals output from the plurality of conversion means are configured to be compared by the comparison means. The magnetic disk device according to claim 1.