JP2001250343A - Magnetic recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an information recording and reproducing device which realizes writing of high reliability even when an off-track error is generated. SOLUTION: The information recording and reproducing device has a head 2 which writes-in/reads-out signals onto a recording medium 8 in which a plurality of divided recording areas are formed on a plurality of recording tracks 40, a means 36 for rotating driving the recording medium 8, a means for positioning the head 2 on the recording track 40 and a means for detecting position-shifting of the head 2 on an objective recording track. In this information recording and reproducing device, when position-shifting is detected at the time of writing-in information, information is rewritten from the recording area of a rotation downstream side of the recording medium 8 from the head position when the position shifting is detected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording / reproducing apparatus, and more particularly to an information recording / reproducing apparatus for recording / reproducing a magnetic disk held rotatably inside the apparatus by using a magnetic head.

[0002]

2. Description of the Related Art A conventional information recording / reproducing apparatus will be described with reference to FIG. 2. Description of the Related Art As a conventional information recording / reproducing apparatus, for example, a hard disk drive is generally called a hard disk drive, which rotates a magnetic disk having a magnetic recording layer formed on a hard disk surface and writes / reads information with a head floating on the magnetic disk. Is known. Such a hard disk drive comprises a magnetic disk 8 attached to a rotary drive means 36, an arm 4 for transferring the magnetic head 2 to a desired read / write position with the magnetic head 2 attached to the tip and the coil 5 attached to the other end. And the coil 5
And a driving circuit 17 for the arm 4 comprising a pair of yokes 6 and magnets 7 provided opposite the coil 5, a driving circuit for controlling these, and a control circuit for controlling reading and writing of signals from the magnetic disk 8. And a control board 10.

Next, the format of a magnetic disk used in such a conventional information recording / reproducing apparatus will be described. A plurality of tracks are formed on the magnetic disk in order to record information in the radial direction, and each track has a plurality of recording areas called sectors, which are divided in the circumferential direction. Each sector, which is a recording area, is divided into a servo area in which servo information such as a track number is written, a burst area for subsequent tracking, and a data area in which data from the host system is recorded. , And a plurality of these are continuously provided on the track.

Next, writing of data from the host system to the information recording / reproducing apparatus thus formatted will be described. The information recording / reproducing apparatus which has received the write request from the host system moves the head to a desired track based on the servo information on the magnetic disk, and burst signals A and B written in a staggered manner in the burst area. The fine tracking to the center position in the width direction of the desired track is performed by comparing the output values of the desired track. The information transferred from the host system is converted into a signal by the control circuit and sent to the magnetic head, whereby writing to the magnetic disk is performed.

[0005] Such an information recording / reproducing apparatus is connected to a host system such as a computer, which is a host apparatus, and records / records information such as data in response to a request from the host system.
For the reproduction, the information recording / reproducing apparatus is started from the host system by the following method, for example.

When the power of the host system is turned on, the host system sends an ID to the connected information recording / reproducing apparatus.
Send an ENTIFY command. The information recording / reproducing apparatus that has received the IDENTIFY command reads out parameters such as the number of physical cylinders, heads, and sectors stored in advance in storage means such as a ROM in the information recording / reproducing apparatus, and sends them to the host system. Next, the host system checks whether the received parameters are compatible with the host system, and if so, replaces the received parameters, that is, the number of physical cylinders, heads, and sectors with the number of logical cylinders. The information recording / reproducing apparatus operates as the number of logical heads and the number of logical sectors.

[0007]

In such an information recording / reproducing apparatus, when data is written from a host system, if the apparatus is subjected to external vibration or impact, the position of the magnetic head deviates from a desired track and the information is turned off. A track error sometimes occurred. In such a case, the information recording / reproducing apparatus temporarily suspends the writing operation, performs an error recovery process to return the magnetic head to the normal writing position,
The writing operation is resumed after the magnetic head returns to the normal writing position. Here, the restart of the write operation will be further described. Write at the time of restart is started from the sector where the off-track error is detected. However, it is considered that the actual occurrence of the off-track of the magnetic head occurs continuously from the sector several sectors before the sector determined as the off-track error. This is mainly due to the required time from the detection of the current position of the magnetic head to the determination of off-track. Therefore, in the conventional information recording / reproducing apparatus, the output level becomes low when reading data even in a sector several sectors before the sector determined to be an off-track error, which may lead to a read error.

The present invention has been made in view of such circumstances, and an object thereof is to provide an information recording / reproducing apparatus which realizes highly reliable writing even when an off-track error occurs. It is in.

[0009]

Therefore, as means for solving the above-mentioned problems, writing / reading of signals to / from a recording medium having a plurality of divided recording areas formed on a plurality of recording tracks is performed. An information recording / reproducing apparatus having a head for performing, a means for rotating and driving a recording medium, a means for positioning the head on a recording track, and a means for detecting a displacement of the head on a target recording track; Sometimes, when the displacement is detected,
Information is rewritten from the recording area on the downstream side of the rotation of the recording medium from the head position at the time of detecting the displacement.

[0010]

According to the above means, even if an off-track error occurs at the time of writing, information is rewritten not only in the recording area where the positional deviation is detected but also in the recording area where the positional deviation is likely. Thus, highly reliable writing can be performed.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings, taking a magnetic disk drive as an example. FIG.
1 is a perspective view showing the entirety of a magnetic disk drive as an information recording / reproducing apparatus embodying the present invention, FIG. 2 is a block diagram of a control circuit of the magnetic disk drive according to the embodiment, and FIG. FIG. 4 is a diagram showing a format of a magnetic disk of the magnetic disk drive according to the embodiment, FIG. 4 is a circuit diagram of a starting parameter switching means of the magnetic disk drive according to the embodiment, and FIG. 5 is a magnetic disk drive according to the embodiment; 5 is a flowchart relating to the off-track error recovery at the time of writing data in Table 1.
Is a startup parameter table of the magnetic disk drive according to the embodiment.

This type of magnetic disk drive includes a chassis 1, a magnetic disk 8 having a hard disk with a magnetic layer formed on the surface thereof, and a magnetic disk 8 exposed on the upper surface of the chassis 1.
A spindle motor 36 as a rotary drive mechanism for rotatably supporting the magnetic disk, a substantially triangular support plate 3 having a magnetic head 2 protruding at its tip for writing / reading a signal facing the magnetic disk, and one end at one end. An arm 4 to which a support plate 3 is attached and a flat coil 5 is adhesively fixed to the other end, a pair of yokes 6 and magnets 7 fixed to the chassis 1 to face the coil 5, and control of the magnetic disk drive. It mainly comprises a control board 10 on which circuits are mounted. The arm 4 is rotatably supported on the chassis 1 about a pivot shaft 9, and is energized by a VCM 17 including the coil 5, the yoke 6, and the magnet 7, thereby moving the magnetic head 2 in the radial direction of the magnetic disk 8. Drive. R /
One end of a flexible circuit board 15 on which the W amplifier 14 is mounted and fixed on the upper surface of the chassis 1 is connected to the arm 4,
The other end is connected to the control board 10. The control board 10 is provided at one end with a connector 11 for transmitting and receiving signals from a host system (not shown), a connector 12 for supplying power from the host system, and a jumper 18 to which a short pin plug 13 is attached. Then, except for the control board 10, the magnetic disk 8, the spindle motor 36,
The components such as the arm 4, the VCM 17, and the flexible circuit board 15 are hermetically housed between the chassis 1 and a lid (not shown), and the control board 10 is fixed to the lower surface of the chassis.

The control board 10 includes a magnetic disk drive 3
Hard disk control CPU 21 for controlling the interface between the host computer 20 and the host system 20 and the format management and error correction of the magnetic disk drive 37
And a mechanical control CPU 23 for mechanically controlling the magnetic disk drive 37 are mounted, and these two CPUs form the core of the control of the magnetic disk drive 37. The mechanical control CPU 23 includes a hard disk control CPU 21, a servo timing generator 25, a track register 26, an A / D converter 27,
Each of the spindle motor drivers 35 is connected so that signals can be transmitted and received in both directions.

The hard disk control CPU 21 is connected to a buffer RAM 22, a data processing circuit 24, and a ROM 34 in which start-up parameters are written so that signals can be transmitted and received in both directions. The host system 20, which is a host system, is connected so that signals can be exchanged in both directions.

A data processing circuit 24, a pulse detector 31, and a peak detector 33 are connected to the output terminal of the servo timing generator 25. A spindle motor 36 is bidirectionally signaled to a spindle motor driver 35. Connection is possible. A D / A converter 28 is connected to an output terminal of the mechanical control CPU 23, an analog correction circuit 32 is connected to an output terminal of the D / A converter 28, and a VCM driver 30 is connected to an output terminal of the analog circuit 32. The output terminal of the VCM driver 30 is connected to the VCM 17 via the flexible circuit board 15.
It is connected to the.

The magnetic head 2 and the R / W amplifier 14 are connected via the flexible circuit board 15 so that signals can be transmitted and received in both directions. The output terminal of the R / W amplifier 14 has a pulse detector. 31 and a pulse detector 3
The output terminal 1 is a data processing circuit 24, a servo decoder 2
9, connected to the peak detector 33, and the output terminal of the data processing circuit 24 is connected to the R / W amplifier 14. The output terminal of the servo decoder 29 is connected to the servo timing generator 25 and the track register 26. The output terminal of the peak detector 33 is A / D
Connected to converter 27.

On the magnetic surface of the magnetic disk 8, a plurality of recording tracks 40 are formed in the radial direction. FIG. 3 is a schematic diagram in which this recording track is opened linearly. The recording track 40 is divided into a plurality of sectors 41 in the circumferential direction.
In these sectors 41, servo sectors 42 used for tracking in the rotation direction A of the magnetic disk 8 in FIGS. 1 and 3 and data sectors 43 to which data is subsequently written are formed alternately. A servo areas 44 in which servo information such as track numbers are written, and A bursts 45 and B in a staggered manner with the center lines of the recording tracks 40 adjacent to each other as boundaries.
A burst 46 is provided. The data sector 43 has an ID section 47 in which positional information such as a cylinder number, a head number, and a sector number are written, a data section 48 in which information from the host system is recorded, and error correction information. An ECC unit 49 in which is written is provided.

Here, an air bearing surface (not shown) is formed on the surface of the magnetic head 2 facing the magnetic disk 8, and the magnetic disk 8 is driven by a spindle motor 36.
The magnetic head 2 floats on the surface of the magnetic disk 8 while maintaining a small gap by the airflow generated by the high speed rotation of the magnetic disk passing through the air bearing surface. Then, the magnetic disk drive 37 exchanges data with the host system 20 in response to a request from the host system 20.

Next, the means for switching the starting parameters of the magnetic disk drive 37 will be described with reference to FIG.

[0020]

[Table 1]

The hard disk control CPU 21 is connected to a ROM 34 in which startup parameters are stored. The ROM 34 will be further described.
34, the number of cylinders, the number of heads, and the number of sectors are stored in advance as a table of startup parameters as shown in Table 1 at the time of shipment or by the user.
Then, the jumper 1 provided at one end of the control board 10
8 is a pair of connection pins 18a, 18b and 18 respectively.
c, 18d. The short pin plug 13 includes a resin case 13 and a conductive connection piece, and the connection piece is housed and held in a hole formed in the case. Then, one connection pin 1 of the jumper 18
8a and 18c are respectively connected to a power supply via resistors, and the connection pins 18a and 18c are connected to the identification terminals 50,
51 connects to the hard disk control CPU 21 of the control board 10. The other connection pins 18b and 18d are each grounded via a resistor. The connection between the connection pins 18a and 18b and between the connection pins 18c and 18d of the jumper 18 can be switched between short-circuited and open-circuited by mounting the short pin plug 13 at the time of shipment or by a user.

Next, the magnetic disk drive 37 of the present invention will be described.
Will be described from the host system 20. When the power of the host system 20 is turned on, the host system 20 sends an I / O signal to the connected magnetic disk drive 37.
Send a DENTIFY command. Where IDEN
The TIFY command is a command used in a computer conforming to the AT standard. IDENTIFY
Upon receiving the command, the hard disk control CPU 21 of the magnetic disk drive drives the identification terminal 50,
In response to the output of 51, the corresponding start-up parameter is read from the parameter table of the ROM 34 and transferred to the host system. For example, the shorting plug 13 is connected between the connection pins 18a-18b and short-circuited.
When the jumper plug 13 is not connected between the terminals d and is in an open state, the output of the identification terminal 50 is at a low level and the output of the identification terminal 51 is at a high level and sent to the hard disk control CPU 21. As a result, the hard disk control CPU 21
The corresponding parameters, that is, the number of cylinders 615, the number of heads 8, and the number of sectors 17 are read from the parameter table of No. 4 and transferred to the host system.

Next, the host system 20 checks whether or not the received parameters are compatible with the host system 20. As for the transferred parameters, those that are compatible with the host system 20 are selected in advance from the parameter table. Therefore, there is no possibility that an error will occur because the host system is not adapted. The magnetic disk drive operates with the parameters received by the host system 20 as the number of logical cylinders, the number of logical heads, and the number of logical sectors.

In this embodiment, the number of cylinders, the number of heads,
Each of the number of sectors is stored in the parameter table, but one or two of the above parameters such as only the number of cylinders or only the number of cylinders and the number of heads are used in combination within a range compatible with the host system. You may do so. Also, the switching means has been described using a combination of two sets of shorting plugs and connection pins. However, the number of switching means may be increased or decreased according to the number of parameters, or switching may be performed by using other selection means such as a slide switch. It may be.

Next, the read operation of the magnetic disk drive 37 according to the present invention will be described. The magnetic disk drive 37 started by the host system 20 includes:
By rotating the spindle motor 36, the magnetic disk 8
To rotate at high speed. An air bearing surface (not shown) is formed on the surface of the magnetic head 2 facing the magnetic disk 8, and the air flow generated by the high speed rotation of the magnetic disk 8 passes through the air bearing surface. The magnetic head 2 flies above the surface of the magnetic disk 8 while maintaining a small gap.

When a seek command is received from the host system 20, the seek command is input to the mechanical control CPU 23 via the hard disk control CPU 21, and the seek signal from the mechanical control CPU 23 is transmitted to the D / A converter 28 and the analog correction circuit 32. Through V
The signal is input to the CM driver 30, and the VCM driver 30
A sufficient current is supplied to the CM 17 to seek the target track. In this way, the arm 4 on which the VCM 17 is mounted rotates in the radial direction of the magnetic disk 8, and transfers the magnetic head 2 to a target track. The R / W gap (not shown) of the magnetic head 2 detects a magnetic change in the magnetization pattern of the recording track 40 on the magnetic disk 8 and generates a read voltage by a coil (not shown) in the magnetic head 2.

This read voltage is amplified by the R / W amplifier 14 and then sent to the pulse detector 31 to be converted into a pulse signal. This pulse signal is sent to the servo decoder 2
9, and servo information such as a track number is read from the pulse signal. The track number read out here is stored in the track register 26 and can always be referred to from the mechanical control CPU 23.

The subsequent A and B bursts are read out,
The signal is sent to the peak detector 33. When receiving the detection command signal from the servo timing generator 25, the peak detector 33 holds the read voltage of the A and B bursts at that moment,
/ D converter 27. The A / D converter converts the held read voltage into a digital value, and the mechanical control CPU 23 reads the digital value of the A / D converter 27 and compares the magnitude of the digital value to thereby determine the value of the magnetic head. The amount of off-track, which is the amount of deviation from the track center, can be calculated. Based on this amount of off-track, fine tracking is performed, and positioning to the desired recording track is completed.

The read voltage read from the desired recording track is sent from the pulse detector 31 to the data processing circuit 24, converted into an NRZ signal, and sent to the hard disk control CPU 21. The hard disk control CPU 21 converts the NRZ signal into digital signal data, sends it to the host system 20, and the read operation is completed.

Next, a write operation of the magnetic disk drive 37 according to the present invention will be described. When there is a data write request from the host system 20, the digital signal data is sent to the hard disk control CPU 21 of the magnetic disk drive 37, and the data is once sent to the buffer RAM 22 and held. On the other hand, the hard disk control CPU 21 is
A track number and a head number, which are target write positions, are designated to 3. Then, the mechanical control CPU 23 refers to the current position of the magnetic head, calculates the seek amount up to the target position, and inputs a seek signal to the VCM driver 30 via the D / A converter 28 and the analog correction circuit 32.
Then, the VCM driver 30 supplies a sufficient current to the VCM 17 to seek to the target track, and the arm 4 on which the VCM 17 is mounted is rotated in the radial direction of the magnetic disk 8 to transfer the magnetic head 2 to the target track. When the seek of the magnetic head 2 to the target position is completed in this way, the mechanical control CPU 23 sends a signal of the seek completion to the hard disk control CPU 21.

Next, a hard disk control CPU
21 reads data from the buffer RAM 22 and outputs NR
The signal is converted into a Z signal and sent to the data processing circuit 24. The data processing circuit 24 encodes the NRZ signal into 1,7 RLL or the like, and writes the NRZ signal on the recording track 40 of the magnetic disk 8 via the R / W amplifier 14 and the R / W gap (not shown) of the magnetic head 2. Be included. Here, the hard disk control CPU 21 knows from the write request from the host system 20 how many sectors to write data in, starting from which sector, and the remaining data is written each time data writing to one sector is completed. The number of sectors to be written is decremented one by one. When the number of remaining write sectors becomes zero, it is determined that the writing has been completed, and a signal indicating that the host system 20 is in a command waiting state is transmitted.

Next, a write operation when an off-track error occurs in the magnetic disk drive 37 according to the present invention will be described with reference to the flowchart of FIG. As in the above-described read operation, a write request from the host system 20 is received, the head moves to the write target position in step S1, and the mechanical control CPU 23 determines in step S2 the magnitude of A / B burst read voltage A / B. By comparing the digital value of the D converter 27, the off-track amount with respect to the center position of the target recording track 40 is calculated, and it is confirmed whether or not off-track has occurred for each sector. And the above A /
If the comparison result of the digital value of the D converter 27 exceeds the allowable value, in step S3, the mechanical control CP
U23 determines that off-track has occurred, and determines in step S
In step 4, an error occurrence signal is sent to the hard disk control CPU 21.

Next, in step S5, the hard disk control CPU 21 receiving the signal of the error occurrence
Suspends the writing operation in step S6. Then, although the process proceeds to the error recovery operation from step S7, first, the number (n) of the sector in which the error has occurred is calculated from the relationship between the number of the first sector to which data is written and the number of sectors waiting to be written. Then, the buffer RAM 22 reads the sector number (n) where the error occurred and the data assigned to be written to the immediately preceding sector number (n-1). Next, in step S8, the hard disk control CPU 21 waits until the magnetic disk 8 rotates to a writable position for the sector number (n-1) immediately before the sector number (n) for which it is determined that an error has occurred, and In S9, when the above-mentioned writable position is reached, the WRITE gate is opened, and the sector number (n) determined to have caused the error
Then, data is rewritten to each sector of the sector number (n-1) immediately before that, and the error recovery work is completed.

In the above embodiment, data is rewritten from the sector immediately before the sector in which the off-track error has occurred. However, the mechanical control CPU 23 determines that an off-track error has occurred, and the hard disk control CPU 21 generates an error. The number of sectors to be written is compared with the time required for sending the signal and the time required for the hard disk control CPU 21 to receive the error generation signal and the time required for suspending the writing operation. Alternatively, rewriting may be performed from a sector having a sector number earlier than the error occurrence sector number by the number of the sectors. In the above embodiment, the description has been given of the case where the magnetic disk drive is controlled by two CPUs. However, all the controls may be performed by one CPU.

The magnetic disk drive 3 according to the present invention
7 has an ECC correction function for correcting data when an error occurs during data reading in order to improve reliability. Depending on the host system, such an EC may be used when starting up the magnetic disk drive.
Some diagnose the C correction function. The diagnostic test will be further described.
Based on the AD LONG command, the data and ECC information read from the magnetic disk are sent to the host system. Next, the read data is rewritten so that an error occurs intentionally in the host system, and then the rewritten data and the read ECC information are rewritten on the magnetic disk. Then, the data is read again from the magnetic disk by a READ command from the host system, and diagnosis is made based on whether or not an error has occurred.

Here, in the magnetic disk drive 37 according to the present invention, a READ LON from the host system is performed.
Data and EC from magnetic disk when receiving G command
The C information is read at least twice each time, and after confirming that there is no reading error by comparing the first and second results, the read data and ECC information are sent to the host system. That is, since the diagnostic test is performed after confirming that there is no error in the data or the ECC information as the sample of the diagnostic test, the diagnostic test of the ECC correction function can be performed more accurately.

[0037]

As described above, according to the present invention, a head for writing / reading a signal to / from a recording medium having a plurality of divided recording areas formed on a plurality of recording tracks, and rotating the recording medium are provided. Means for driving, means for positioning the head on a recording track, and means for detecting a displacement of the head on a target recording track, the information recording / reproducing apparatus, when the displacement is detected at the time of writing information, Since the information is rewritten from the recording area on the downstream side of the rotation of the recording medium from the head position at the time of detecting the positional deviation, even if an off-track error occurs at the time of writing, if only the recording area where the positional deviation is detected is provided. In addition, since information is rewritten to a recording area where there is a possibility of displacement, highly reliable writing can be performed. Achieve the.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an entire magnetic disk drive according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a control circuit block of the magnetic disk drive according to the embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a format of a magnetic disk of the magnetic disk drive according to the embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a starting parameter switching circuit of the magnetic disk drive according to the embodiment of the present invention.

FIG. 5 is an explanatory view showing off-track error recovery during writing of the magnetic disk drive according to the embodiment of the present invention.

FIG. 6 is an explanatory diagram showing an entire magnetic disk drive as a conventional information recording / reproducing apparatus.

[Description of Signs] 13 Short pin plug 18 Jumper 20 Host system 21 Hard disk control CPU 23 Mechanical control CPU 34 ROM 37 Magnetic disk drive 50, 51 Identification terminal

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) G11B 20/18 576 G11B 20/18 576A G06F 3/06 305 G06F 3/06 305Z G11B 19/02 501 G11B 19/02 501B (72) Inventor Koji Ajita 1-7 Yukitani Otsukacho, Ota-ku, Tokyo Alps Electric Co., Ltd. (72) Inventor Masaaki Sato 1-7 Yukitani Otsuka-cho, Ota-ku, Tokyo Alps Electric Co., Ltd.

Claims (1)

[Claims] 1. A head for writing / reading a signal to / from a recording medium having a plurality of divided recording areas formed on a plurality of recording tracks, means for driving the recording medium to rotate, and recording the head. In an information recording / reproducing apparatus having a means for positioning on a track and a means for detecting a displacement of the head on a target recording track, if the displacement is detected at the time of writing information, recording is performed from the head position at the time of detecting the displacement. An information recording / reproducing apparatus for rewriting information from a recording area on the downstream side of rotation of a medium.