JP2002184128A - Defective position detecting method and seek control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a defective position detecting method and a seek control method performing control for making a head seek at the prescribed cylinder of a recording medium and to reduce the cost of a magnetic disk device by performing the normal positioning control of the head even when the device has the defect related to positional information at the recording medium. SOLUTION: In this device, defective position data related to the positional information on a magnetic disk 52 are stored at least in a ROM(read only memory) 39 and a defective position judging means 37 judges a seek route and judges whether a defective position exists in the seek route or not before starting seek. Then, the device is made to have constitution in which when the defective position exists in the seek route, a seek control means 38 makes a seek operation to be performed by supplying a control current to a VCM(voice coil motor) 48 while changing over a R/W head 44 performing the seek to another head or replacing the positional information with extracted data with which the defective position is predicted or adjusting a seek starting timing so that the defective position is not included in the seek route.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defect position detecting method and a seek control method for controlling a head to seek a predetermined cylinder of a recording medium.

In recent years, storage devices such as magnetic disk devices have
High reliability and low cost are always required. In order to obtain high reliability, an expensive recording medium with few defects is required, and when an inexpensive recording medium is used, defective portions increase. If there is a portion in which servo information of a defect is recorded, seek control of the head cannot be performed, and it is desired that normal positioning control of the head can be performed even if a defect exists.

[0003]

2. Description of the Related Art FIG. 14 is a schematic block diagram of a conventional magnetic disk drive. Magnetic disk device 1 shown in FIG.
1, a predetermined number of magnetic disks 12 (1 in FIG. 14)
A predetermined number of magnetic heads 13 (only one is shown in FIG. 14) are arranged in correspondence with the magnetic heads 13.
Are selected and operated by the head IC (HDIC) 14. The head IC 14 has a read channel (RDC) 15
The read channel 15 includes an encoder, a decoder, and the like.

[0004] The reproduction system of the read channel 15 converts the reproduced waveform into a digital signal by an A / D converter 16 and outputs the converted signal to the MC.
U (micro control unit) 17 The recording system of the read channel 15 receives the write data from the HDC (hard disk controller) 18 and records the data in a predetermined data area of the magnetic disk 12 by the magnetic head 14 selected by the HDIC 14. The HDC 18 is connected to a RAM (random access memory) 19,
The CU 17 has a RAM 20 for executing a program and the M
A ROM (Read Only Memory) 21 for storing the program of the CU 17 is connected.

The MCU 17 has an SPM (spindle motor) 2 for rotating the magnetic disk 12 at a predetermined rotation speed.
2 and a VCM (voice coil motor) 23 for seeking the magnetic head 13 in the radial direction of the magnetic disk 12.
A / D converter 24 and servo driver (SRVDR
V) An appropriate current is supplied via 25 to drive control.

Here, the magnetic disk 12 has a data portion in which data is written and a servo frame portion in which servo information such as position information is written, for each cylinder of a sector portion of the magnetic disk 12 divided in the radial direction. Is formed in a predetermined number.

Here, the magnetic head 13 is mounted on the magnetic disk 1
MCU when reading / writing data to / from
Reference numeral 17 controls the drive current of the VCM 23 according to the distance between the current position of the magnetic head 13 on the magnetic disk 12 and the target position, and seeks from the current position to the target position. At this time, the MCU 17 performs seek control by calculating the amount of current supplied to the VCM 23 within the sampling interval based on the servo information obtained at every sampling time interval determined from the rotation period of the SPM 22 and the number of sectors on the magnetic disk 12. Things.

Subsequently, the MCU 17 moves the magnetic head 13 to the vicinity of the target track, and then reads the cylinder address recorded on the servo frame portion of the magnetic disk 12 based on the position signal obtained by reading the cylinder address.
3 so that the error is always zero on the cylinder.
A small amount of current is supplied to the motor to perform a following operation for on-tracking, and the magnetic head 13 is controlled to be positioned on a target cylinder of the rotating magnetic disk 12.

Next, the read channel (RDC) 15
A gate signal for reading / writing data is output, and reading / writing is performed at the timing of the gate signal. In this case, in order to read / write data accurately, it is necessary that the information in the data portion and the servo frame portion on the magnetic disk 12 have no defective portion and that the signal expected from the magnetic head 13 can be read. However, there is a case where the magnetic disk 12 has a defective defect area.

When the data section has a defect area, it can be dealt with by replacing the data area with a replacement area on the magnetic disk 12. If the servo frame portion has a defect area, reformatting is performed again to avoid a defective portion, or the magnetic disk is discarded.

This is because when the servo frame portion has a defect area, when accessing all data on the magnetic disk 12, the magnetic head 1 is used during a seek operation.
When 3 crosses the defective portion, noise is added to the position signal, which may cause a seek error and make it impossible to read / write data normally. Further, even when the magnetic head 13 does not cross the defective portion, when the target position is a defective cylinder, it is not possible to perform on-track and read / write data.

[0012]

However, as described above, if the position information for positioning the magnetic head 13 on an arbitrary cylinder has a defect, the magnetic head 13
However, there is a problem that a seek operation for moving the target to a target position at a high speed and a following operation for accurately following the cylinder cannot be performed, and that the cost is increased when the format is redone or discarded.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and a defect position detecting method and seek control for performing normal positioning control of a head even if a recording medium has a defect relating to position information to reduce costs. The aim is to provide a method.

[0014]

According to a first aspect of the present invention, for a predetermined number of recording media, position information recorded on the recording media is assigned to a corresponding one of a predetermined number of heads. In the method of detecting a defect position of the storage device when the head reads and positions and follows the target position on the recording medium based on the position information, the head corresponding to an arbitrary surface corresponding to all the recording media Causing the head to be on-track based on the position information read by the head, and determining the off-track state of the head corresponding to a surface other than an arbitrary surface of the recording medium to obtain the correctness of the position information. For all the surfaces of all the recording media, the above steps are repeated to obtain the correctness of all the position information. The defect position detection method of a storage device is configured to include a step of recording all of the position data, the.

According to a second aspect of the present invention, the position information recorded on the predetermined number of recording media is read out by a corresponding head among the predetermined number of heads, and the head is read out based on the position information. In a method of detecting a defect position of a storage device when positioning and following a target position on a recording medium,
Each of the recording medium is divided into a predetermined number of recording areas, the head on the corresponding recording medium corresponding to an arbitrary recording area on the track based on the read position information, Determining a corresponding off-track state of the head based on the position information read from the recording area other than an arbitrary recording area of the recording medium, and obtaining the correctness of the position information; Repeating the above steps for all recording areas to obtain the correctness of all the position information, and obtaining only the defective position data or all the position data among the correctness / error data of the position information; and The above steps are repeated for all the corresponding heads to obtain all the position data or only the defect position data for all the heads. Defect position detection method of a storage device is formed a step to be stored, a comprise.

According to a third aspect of the present invention, for a predetermined number of recording media, the position information recorded on the recording medium is read out by the head of the predetermined number of heads, and the head is recorded based on the position information. 3. A seek control method for a storage device for positioning and following a target position on a medium, wherein the seek of the head is performed before the start of seek based on the position data or defect position data of the recording medium stored in claim 1 or 2. Predicting a path and determining whether or not a defect position exists in the seek path; and selecting a head other than the corresponding head when the seek path has the defect position; Performing a seek operation while reading data from the head, and returning the head selection to the original head after the seek is completed. But composed.

According to a fourth aspect of the present invention, the position information recorded on the predetermined number of recording media is read out by the corresponding head among the predetermined number of heads, and the head is recorded based on the position information. 3. A seek control method for a storage device for positioning and following a target position on a medium, wherein the seek of the head is performed before the start of seek based on the position data or defect position data of the recording medium stored in claim 1 or 2. Estimating a path and determining whether or not a defect position exists in the seek path; and, when the seek path has the defect position, extracting the defect position in the seek path and extracting the corresponding position. Setting the position;
Starting the seek of the corresponding head, and actually measuring the defect position by reading the position information; and, when the head is located at the defect position, performing a seek operation using the information of the set extraction position. And a step of performing a seek control method of the storage device.

According to a fifth aspect of the present invention, the position information recorded on the predetermined number of recording media is read out by a corresponding head out of the predetermined number of heads, and the head is read out based on the position information. 2. A seek control method for a storage device for positioning and following a target position on a recording medium.
Or, based on the position data or defect position data of the recording medium stored in step 2, the seek path of the head is predicted before the seek starts, and it is determined whether or not the defect position exists in the seek path. Adjusting the seek start timing so that the defect position does not exist in the seek path when the seek path has the defect position; and And a step of performing a seek operation of the storage device.

As described above, according to the first aspect of the present invention, when detecting at least the defect position data stored in the storage means, the head is turned on-track based on the position information obtained on an arbitrary surface of the recording medium. The off-track state of the relevant head on the surface other than the surface is determined, and the correctness of the position information is obtained to obtain position data including the defect position data on all the surfaces. This makes it easy to obtain defect position data,
It is possible to provide for normal positioning control of the head.

According to the second aspect of the present invention, when detecting at least the defect position data to be stored in the storage means, the head is turned on based on position information obtained in an arbitrary recording area among the divided recording areas of the recording medium. The head is tracked, the off-track state of the head in a recording area other than an arbitrary recording area is determined, and the correctness of the position information is obtained to obtain position data including defect position data of all the recording areas of all the recording media. As a result, defect position data can be easily obtained, and can be used for normal positioning control of the head.

According to the third aspect of the present invention, when there is a defect position in the seek path by the judgment of the defect position judging means before the start of the seek, the seek is performed based on the position information obtained from another head, and after the seek, the original seek is performed. Switch to head. This makes it possible to seek the relevant head irrespective of the defect position, and to avoid occurrence of an error at the defect position.

According to the fourth aspect of the present invention, when there is a defect position in the seek path determined by the defect position determination means before the start of the seek, the position information of the defect position is replaced with the extraction information extracted by the defect position data to perform the seek. Let it. As a result, it is possible to avoid occurrence of an error at the defect position.

According to the fifth aspect of the present invention, when there is a defect position in the seek path by the judgment of the defect position judgment means before the start of the seek, the seek start timing is adjusted so as not to have the defect position in the seek path. . As a result, the head is sought while avoiding the defective position, and normal positioning can be performed.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a configuration diagram of an embodiment of the present invention. FIG. 1 shows a magnetic disk device 3 as a storage device.
1, which is a block diagram showing the configuration of a host computer 32, which is connected to a host computer 32, which is a host device, via interface devices (scuzzy devices) 33a and 33b.

The magnetic disk drive 31 includes an HDC (hard disk controller) 35 in the interface circuit 34.
And MPU (microprocessor) 3
6 is connected. The MPU 36 has a program of a defect position judging means 37 for judging a seek path of a relevant head, which will be described later, and judging whether or not the defect position exists in the seek path based on the defect position data. When a seek path has a defect position, a program of a seek control means 38 (described later) for avoiding an error at the defect position and seeking the head based on the defect position data based on the defect position data is provided.

The MPU 36 is a ROM (Read Onl) which is a storage means for storing all the position data including the above-mentioned defect position data or only the defect position data.
yMemory) 39 and RAM (Random Ac)
cess Memory) 40 is provided. MPU3
Various commands such as a read command and a write command are input to the host computer 6 via the interface circuit 34 from the host computer 32.

On the other hand, the HDC 35 is provided with a buffer 41 for temporarily storing the user data input to the HDC 35, reading it out at the time of writing according to the write gate signal from the MPU 36, and outputting it to the read channel (RDC) 42. Data is supplied from the predetermined number of R / W (read / write) heads 44 to the selected R / W heads via the head IC 43. The RDC 42 includes an encoder, a decoder, and the like as described above.
Supplies data to the encoder system. Also, RD
The R / W head 44 selected from the C42 decoder system
Read data obtained by decoding the read waveform from
(Analog to digital converter) MP via 45
It is supplied to U36.

On the other hand, the MPU 36 includes a seek control means 38
A control current is supplied to a VCM (voice coil motor) driver 47 via a DAC (digital / analog converter) 46 based on a seek control from the VCM 48, and the VCM driver 47 drives the VCM 48 to drive the R / W head 44. The seek operation is performed by moving the magnetic disk in a radial direction described later.

The MPU 36 supplies a rotation control current to an SPM (spindle motor) driver 50 via a DAC 49, rotates the SPM 51 from the SPM driver 50, and rotates a predetermined number of magnetic disks 52 (format is a recording medium). Is rotated at a predetermined speed. The R / W heads 44 are provided respectively corresponding to the magnetic disks 52 as described later. For example, in the case of a data surface servo system in which both surfaces of the magnetic disk 52 are used as surfaces for storing data, / W heads 44 are provided on both surfaces of each magnetic disk 52.

Here, FIG. 2 shows an internal perspective view of the magnetic disk drive of FIG. 1, and FIG. 3 shows a sectional view taken along the line AA of FIG. 2 and 3, the spindle 51a of the SPM 51 is placed in the enclosure 62 on the base 61.
A predetermined number of magnetic disks 52 are rotatably mounted on the disk.

On the other hand, the actuator 63 has an R /
A predetermined number of arms 65 to which a support spring mechanism 64 on which the W head 44 is mounted are fixed to the rotating shaft. A VC composed of a voice coil 67 and a magnet 68 is provided on the arm 65 on the opposite side of the rotary shaft 66 from the R / W head 44.
M48 is provided.

A printed circuit board 69 on which the head IC 43 and the like are mounted is connected to the VCM 48 via an FPC (flexible printed board) 70. The printed circuit board 69 is mounted with the MPU 36 and the like by an FPC (not shown). Connected to the main board 71 that has been set. Further, a cover 73 is mounted on the enclosure 62 via a seal member 72.

FIG. 3 shows a format explanatory diagram of the magnetic disk of FIG. FIG. 3A shows the magnetic disk 52.
A sector SCT as a recording area is formed by dividing a predetermined number in the radial direction from the center, and each sector SCT includes a servo frame section 52a and a data section 52b. And the cylinder CYL
Are formed concentrically.

Therefore, in each cylinder CYL, a servo frame section 52a and a data section 52b are formed for each sector SCT as shown in FIG. 3B. Servo information necessary for each servo is recorded in advance in the servo frame portion 52a, and a cylinder address required for head seek is written as position information, and a data portion 52b is an area for a user to write data. It is.

According to the present invention, when on-tracking the magnetic head 44 on the target cylinder, the head seek can be normally performed even if the position information has a defect due to a medium defect or the like. It is necessary to detect a defect position relating to position information on the disk 44 in advance.

FIG. 5 shows a flowchart of an example of defect position detection. This defect position detection is performed in advance by the magnetic disk device 31 itself, and is performed by the MPU 36 executing a program recorded in the ROM 39, for example.

In FIG. 5, when the self test is started (step (S) 1), a plurality of R / W heads 44
The head number in the program of (head numbers 0, 1, 2,...) Is set to 0 (S2), and the R / W head 44 to be used starts with the head number 0 (even number). Is set. Therefore, the head number 2m (m = 0, 1, 2,..., 2m indicates an even number,
2m + 1 indicates an odd number) R / W head 44 (here, for example, four R / W heads for two magnetic disks 52)
A W head 44 is provided, which seeks a head number 0 among head numbers 0 to 4 onto a predetermined cylinder N (for example, starting from the outermost cylinder), and determines whether or not on-track has been performed. Is performed (S3).

When no on-track operation is performed, even numbers other than the head numbers 2m and 2m + 1 (head numbers 0 and 1) are used.
That is, the even-numbered R / W heads 44 of the R / W heads 44 corresponding to another magnetic disk 52 (for example, head 2)
It is determined whether or not on-track has been performed by seeking (S
4) If this is not the case, the process ends as abnormal (S5).

In S3 or S4, even-numbered R / W
When the head 44 is on-track, the odd number (2
The (m + 1) R / W head 44 (for example, heads 1 and 3) reads servo information in all sectors on the cylinder N on the surface of the magnetic disk 52 to be accessed, and checks an error from the track center (S6). At this time, when the error amount is larger than the reference value, it is possible to determine that the read position information is a defect, and this is checked in all sectors on the cylinder N.

Then, it is determined whether or not the cylinder N checked by the odd-numbered R / W head 44 is the last cylinder (the innermost cylinder when starting from the outermost circumference) (S7). For example, the cylinder number is incremented (S8), and S3 to S6 are repeated until the last cylinder. That is, the R / W of the odd number 2m + 1
A defect position on the surface of the magnetic disk 52 accessed by the head 44 (for example, the head 1) is detected.

When the defect position is detected up to the last cylinder (S7), it is determined whether or not the R / W head 44 of the last head number provided is the head number used for on-track (S9). For example, the head 3 is the final number, and the R / W head 44 used at the defect position is the head 1
And will be different. In S9, if the head numbers are different, the head number obtained by further subtracting 1 from the final head number is the R / W that was first used for on-track.
It is determined whether it is the head number of the head 44 (S1).
0). For example, in the above case, when 1 is subtracted from the final head number, it becomes 2, which is different because the initial head number used for on-track is 0.

Therefore, the head number is incremented (S11), and the cylinder number is set to 0 (S1).
2) For example, S3 to S8 are repeated from the outermost cylinder to detect a defect position. That is, for example, the head 2 is made to be on-track on the cylinder N (if the head 2 is not on-track, the head 0 is made to be on-track), and the defect position for all sectors on the cylinder N on the surface accessed by the head 3 is determined. It is to detect.

When the operation is completed up to the last cylinder (S
7) In S9, the final head number (for example, head 3)
And whether the initial head number (for example, head 2) used for the on-track is the same.
At 0, it is determined whether the head number (for example, head (3-1)) obtained by subtracting 1 from the final head number and the head number (for example, head 2) used for the initial on-track are the same.

The coincidence in S10 means that the track is on-tracked by the even-numbered R / W heads 44, and all the corresponding surfaces of the magnetic disk 52 are detected by the odd-numbered R / W heads 44 as defect positions. It will be.

Therefore, R is determined for each surface of the magnetic disk 52.
Swap the even and odd numbers of the / W head 44 (S1
3) Repeat the above-described defect position detection S3 to S12. In other words, the processes of S3 to S8 are made the same by exchanging even numbers and odd numbers. Actually, the odd-numbered R / W heads 44 (for example, heads 1, 3) before the exchange are actually used.
Are used for the on-track, and the defect position of the access surface is detected by the even-numbered R / W heads 44 (for example, heads 0 and 2).

In S9, if the head number (for example, head 3) for which the original final head number (for example, head 3) is to be used for on-track coincides, each cylinder on the entire surface of each magnetic disk 52 has Is detected for each head, and all the position data including the detected defect position data or only the defect position data is stored in a predetermined portion (described later) ( S14), normal termination (S1)
5).

Next, FIG. 6 shows a flowchart of another example of the defect position detection. The defect position detection shown in FIG. 6 indicates that the on-track and defect position detection are performed not in the head unit of FIG. 5 but in the sector unit of the magnetic disk 52. In FIG. 6, at the start of detection (S21), a flag is first set to 0 (S22). Therefore, given R
The / W head 44 reads the position information of the 2N (even number) sector on the access surface and performs an on-track operation on a predetermined cylinder (S23).
The position of the R / W head 44 on a predetermined cylinder of the (odd) sector is checked for an error from a set value from the track center (S24). If this error is smaller than the reference value, 2
It means that there is no defect in the position information read in N sectors, and when the error is larger than the reference value and the track is off-track, it means that the read position information has a defect. On the other hand, if it is determined in step S23 that the track is not on-track on the predetermined cylinder of the 2N sector, the flag is set to 1 (S25).

Next, the corresponding R / W head 44 is set to 2N +
The on-track operation is performed by reading the position information of one (odd) sector (S26).
The error of the position of the (even) sector on the predetermined cylinder with the set value from the track center is checked (S27). If the error amount is larger than the reference value, it is off-track, and the read position information becomes defect information. After checking, flag 1
Is determined (S28), and if not, it is determined whether the checked cylinder is the last cylinder (S29).

If it is not the last cylinder, the cylinder number is incremented (S30), and the processing from S22 onward for the next cylinder is repeated up to the last cylinder.

On the other hand, if the position information from the 2N + 1 (odd) sector is defect information in S26 and the R / W head 44 is not on-track, it is determined whether or not the flag 1 is set (S31). If it does not stand, the corresponding defect position of the 2N + 1 (odd) sector is skipped to attempt on-track, and it is determined whether or not on-track is performed (S32). The flag 1 is set in S31,
Alternatively, if on-track is not performed in S32, the process ends as an abnormal state (S33). If the track is on-tracked in S32, an error in the position of the R / W head 44 on a predetermined cylinder of 2N (even number) sectors is determined to check whether or not the position is a defect position (S34), and the process proceeds to S29. I do.

On the other hand, in S28, if the flag 1 is set after checking the 2N (even number) sector in S27, the on-track is attempted by stepping the defect position existing in the predetermined cylinder of the 2N sector. It is determined whether or not it has been performed (S35). If the track is not on-track, the process ends as an abnormal state (S33). A check is made (S36), and the flow shifts to S29.

When the defect detection for all the cylinders on the predetermined surface of the magnetic disk 52 is completed (S29), the detection result is stored (S37), and the process ends normally (S3).
8). This is performed on all surfaces of the magnetic disk 52 to be mounted.

It is to be noted that the reading of the position information, the on-track and the defect detection in each sector as shown in FIG. 6 are not performed separately for the even sector and the odd sector, but for the continuous adjacent sector and other sectors. You may arbitrarily divide.

FIG. 7 is an explanatory diagram of the storage of defect position data. The detection results obtained in FIG. 5 or FIG. 6 are obtained for each R / W head 44 for all cylinders in each sector on all magnetic disk surfaces, and are shown in FIG. Thus, a table is formed for each R / W head 44 based on the normal position data and the defect position data,
It is stored in the ROM 39 shown in FIG.
2 is stored in a predetermined reserved area on the outer circumference or inner circumference.

Alternatively, it is possible to prevent an increase in storage capacity by storing only the defect position data. As shown in FIG. 7, a head number (for example, 4 bits), a cylinder number (for example, 13 bits), Only the data of the sector number (for example, 6 bits) may be stored in the reserved area on the ROM 39 or the magnetic disk 52.

Further, data indicating only a defect may be stored in the servo frame section 52a of the corresponding cylinder.

Next, a case where the seek operation of the R / W head 44 is performed based on the detected defect position data will be described.

FIG. 8 shows a flowchart of the seek operation according to FIG. FIG. 8 shows a case where, for example, the defect position data stored in the ROM 39 is tabulated with the normal position data as shown in FIG. In FIG. 8, when a seek command is issued from the host computer 32 (S41), the MPU 36 checks a table in the ROM 39 to determine whether or not defect position data exists on the corresponding magnetic disk surface accessed by the R / W head 44 to be sought. It is determined with reference to (S42), and if it does not exist, the seek control means 38 starts a normal seek operation (S43). Then, the R / W head 44 is positioned on the target position (target cylinder) and tracks on, and tracking control is performed so as not to perform off-track, and the seek is completed (S).
44).

On the other hand, if the defect position data exists on the table in S42, the defect position judging means 37
In FIG. 7, the seek path from the current position to the target position of the R / W head 44 to be sought is determined with reference to the table in FIG. Then, it is determined with reference to the table whether or not the seek path passes through the cylinder in which the defect position exists (S45). If the seek path does not pass through the cylinder, the process proceeds to S43 and the seek control means 38 performs the normal operation. Start seek operation.

On the other hand, when the defect position judging means 37 judges that the seek path passes through the cylinder having the defect position, the distance from the current position of the R / W head 44 to the target position, the seek direction, From the relationship of the rotation speed of the magnetic disk 52, the defect position is determined by the R / W head 44.
7 is determined by the defect position determining means 37 as shown in FIG.
(S46). If it does not pass through the defect position, the flow shifts to S43 to start a normal seek operation.

In S46, the R / W head 44
When the defect position judging means 37 judges that the data passes the defect position, the seek control means 38 switches the head (S47a) or uses the position data predicted by extracting the defect position during the seek. Do (S47
b) Adjust the seek start timing (S47)
The seek operation is completed by on-tracking in any of the methods c) (S44).

FIG. 9 is a flowchart showing a case in which the head is switched as shown in FIG. In FIG. 9, the seek control unit 38 controls the R /
Based on the determination that the W head (head N) 44 passes through the defect position (S51), the R / W head 44 other than the head N is selected (S52), and the selected head number is sent to the defect position determination means 37. Notice. Defect position determining means 37
Then, the defect position data corresponding to the selected R / W head 44 is referred to the table in FIG. 7A (S53), and whether the defect position data should pass through the cylinder where the defect position exists or should pass through the defect position Is determined (S54), the seek control means 38 is notified that another head should be selected when passing through the defect position, and another head is selected (S55), and S53 to S55 are performed. The process is repeated until it does not pass through the defect position.

The R selected by the seek control means 38
When the / W head 44 does not pass through the defect position, the seek operation is started (S56), and the seek operation is completed on-track (S57). After the seek is completed, the R / W head 44 using the head selection for the seek is used to obtain the initial R / W head.
It returns to the W head 44 (S58).

FIG. 10 is a flowchart for the case of the position prediction shown in FIG. In FIG. 10, when the defect position judging means 37 judges that the R / W head 44 passes through the defect position (S61), the next position from the current position and the moving speed of the R / W head 44 to perform a seek. , And a defect position is extracted from the predicted position with reference to the table of FIG. 7A to obtain extracted data (S62).

Then, the seek control means 38 determines that the R /
The seek operation of the W head 44 is started (S63), and the actually measured position is monitored based on the position information read during the seek (S64). When the R / W head 44 reaches the defect position, the defect position information is replaced with the extracted data and used (S65), and the seek operation is completed on-track (S66).

As a result, defect position information can be eliminated, and by using the extracted data, in some cases, a seek operation can be performed on the cylinder of the servo frame portion having the defect position information. Can be recorded and reproduced.

FIG. 11 is a flowchart for the seek timing adjustment of FIG. In FIG. 11, when the defect position judging means 37 judges that the R / W head 44 passes the defect position (S71), it is assumed that the seek control means 38 starts the seek operation after waiting for one sample (see FIG. 11). S72) At this time, FIG.
The seek position is compared with the defect position by referring to the table of (A) (S73). And still, the defect position is R /
When the W head 44 passes, it is further determined whether or not to pass through the defect position after a waiting period of one sample (S74). Adjust the volume.

Then, the seek control means 38 starts the seek operation of the R / W head 44 based on the waiting sample amount that does not pass through the defect position (S75), and completes the seek operation on track (S75). S76). Thus, even if the position information has a defect, a normal seek operation can be performed without passing through the defect position during the seek.

As described above, the seek control means 38 performs the seek operation by any of the above-described methods shown in FIGS. 9 to 11 so that the seek operation can be performed normally even if the position information has a defective portion. You can do it.

Next, FIG. 12 shows a flowchart of the seek operation according to FIG. FIG. 13 is an explanatory diagram of the seek operation shown in FIG. In FIG. 7B, only the defect position data is stored, and the defect position determination means 37 needs to predict the seek path of the R / W head 44 where the seek is performed. In this case, a predetermined number of sampling points are set on a predetermined surface of the magnetic disk 52, and position prediction is performed by calculating a cylinder and a sector number at the sampling points.

For example, a predetermined surface of the magnetic disk 52
Zero sampling points are set, and cylinders (for example, cylinders 0 to 100) and sector numbers (for example, 1 to 60) at each sampling point are calculated. This calculation is based on the amount of current (acceleration) applied to the VCM 48. The velocity and the position can be obtained by differentiating the acceleration. The calculated predicted positions are tabulated as shown in FIG. 13A and stored in, for example, the ROM 39 (or the reserved area of the magnetic disk 52). In this case, the trajectory of the predicted position from the cylinder 0 to the cylinder 100 is indicated by a solid line in FIG.

In FIG. 12, when there is a seek command from the host computer 32 (S81), the defect position judging means 37 refers to the table of the predicted positions (S8).
2) The seek path is determined from the predicted position of the R / W head 44 where the seek is to be performed, and a comparison is made with reference to, for example, defect position data stored in the ROM 39 (S83).
It is determined from the comparison result whether or not the vehicle passes the defect position (S
84) If not, the seek control means 38 starts a normal seek operation (S85), and completes the seek operation on-track (S86).

Then, in S84, when the vehicle passes the defect position in the seek path (the defect position X in the cylinder 75 in FIG. 13B), the head switching (S87a) shown in FIGS. Prediction (S87
b) or seek timing adjustment (S87c), the seek control means 38 performs a seek operation, and completes the seek operation on-track (S86). For example, S8
When 7c is adopted, the seek start timing is adjusted as shown by the broken line in FIG. 13B so that the R / W head 44 does not pass through the defect position in the seek path.

As described above, even if the position information recorded on the magnetic disk 52 has a defect, the position of the defect is detected in advance, and the defect operation is performed by eliminating the defect position information when the defect exists on the seek path. , Normal positioning control can be performed at low cost without adding a new circuit mechanism. This eliminates the need for employing a high-precision magnetic disk, thereby ensuring reliability at low cost. Further, even if the above-mentioned defect is present, it is not necessary to reformat and it is not necessary to discard the defect, so that the cost can be reduced.

Incidentally, Japanese Patent Application Laid-Open No. Sho 59-63065 and Japanese Patent Application Laid-Open No.
What is described in 237270 gazette is known. These have a configuration in which the defect position and the servo head position based on the position signal read during the seek operation are matched, and the position signal at the time of the match is not adopted, and the seek path determined in advance as in the present invention is used. Is different from the configuration in which it is determined whether or not the defect position stored in the memory device exists, unlike the present invention in that a hardware configuration is not required.

Japanese Patent Laid-Open No. 63-1674 discloses that a seek is performed by a head different from the head which originally performs a seek.
Japanese Unexamined Patent Publication No. 88 is known, which attempts to reproduce a servo track having another distortion when an abnormality occurs in a servo track during a seek operation. In this manner, the head is switched from the beginning to perform a seek operation when the seek path determined before the start of the seek has a defective position.

Further, as a method for delaying the start of a seek operation, a method described in Japanese Patent Application Laid-Open No. 64-57465 is known, which detects that the head position coincides with a previously stored defect position. Register to
While a hardware configuration such as a gate and a comparison circuit is required, the present invention determines a seek path and does not require a special circuit to determine whether or not a defect position stored in advance exists. This is different in that it is realized in.

[0078]

As described above, according to the first aspect of the present invention,
When detecting at least the defect position data to be stored in the storage means, the head is turned on-track based on the position information obtained on an arbitrary surface of the recording medium, and the off-track state of the head is determined on a surface other than the arbitrary surface. By discriminating and obtaining the correctness of the position information and obtaining the position data including the defect position data of all the surfaces, the defect position data can be easily obtained and can be used for the normal positioning control of the head.

According to the second aspect of the present invention, when at least defect position data to be stored in the storage means is detected, the head based on position information obtained in an arbitrary recording area among the divided recording areas of the recording medium. Is turned on, the off-track state of the head in a recording area other than an arbitrary recording area is determined, and the correctness of the position information is obtained to obtain position data including defect position data of all the recording areas of all the recording media. Thereby, defect position data can be easily obtained, and can be used for normal positioning control of the head.

According to the third aspect of the present invention, when the seek position is determined by the defect position determination means before the seek starts, the seek is performed based on the position information obtained from another head when the seek position is present, and after the seek, By switching to the original head, it is possible to seek the relevant head irrespective of the defect position, and it is possible to avoid occurrence of an error at the defect position.

According to the fourth aspect of the present invention, when there is a defect position in the seek path determined by the defect position determining means before the start of the seek, the position information of the defect position is replaced with the extracted information extracted by the defect position data. In this case, the occurrence of an error at the defect position can be avoided.

According to the fifth aspect of the present invention, when there is a defect position in the seek path as determined by the defect position determining means before the start of the seek, the seek start timing is adjusted so that there is no defect position in the seek path. By doing so, the head is sought while avoiding the defective position, and normal positioning can be performed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is an internal perspective view of the magnetic disk drive of FIG. 1;

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is an explanatory diagram of a format of the magnetic disk of FIG. 1;

FIG. 5 is a flowchart of an example of defect position detection.

FIG. 6 is a flowchart of another example of defect position detection.

FIG. 7 is an explanatory diagram of storage of defect position data.

FIG. 8 is a flowchart of a seek operation according to FIG.

FIG. 9 is a flowchart in the case of head switching in FIG. 8;

FIG. 10 is a flowchart in the case of the position prediction of FIG.

FIG. 11 is a flowchart in the case of seek timing adjustment of FIG. 8;

FIG. 12 is a flowchart of a seek operation predicted position according to FIG. 7 (B).

FIG. 13 is an explanatory diagram of a seek operation according to FIG. 12;

FIG. 14 is a schematic block diagram of a conventional magnetic disk drive.

[Explanation of symbols]

 Reference Signs List 31 magnetic disk device 32 host computer 34 interface circuit 35 HDC 36 MPU 37 defect position judging means 38 seek control means 39 ROM 40 RAM 42 RDC 43 head IC 44 R / W head 47 VCM driver 48 VCM 50 SPM driver 51 SPM 52 magnetic disk

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) G11B 20/10 G11B 20/10 C 20/12 20/12 F term (reference) 5B065 BA01 CA14 EA15 5D044 BC01 CC05 DE48 DE53 DE64 GK12 GK19 HL02

Claims (5)

[Claims] 1. A head of a predetermined number of heads reads position information recorded on a recording medium for the predetermined number of recording media, and places the head on the recording medium based on the position information. A method for detecting a defect position of a storage device when positioning and following a target position of a recording medium, the method comprising: on-tracking a head on any surface of all the recording media based on position information read by the corresponding head. A step of determining the off-track state of the head corresponding to a surface other than an arbitrary surface of the recording medium to obtain the correctness of the position information; and repeating the above steps for all surfaces of all the recording media. Obtaining the correctness of all the position information and recording only the defective position data or all the position data among the correctness / error data of the position control. Defect position detection method of a storage device according to claim. 2. A predetermined number of heads read out position information recorded on a predetermined number of recording media from the predetermined number of recording media, and based on the position information, the head is read from the recording medium. In the method of detecting a defect position of a storage device when positioning and following a target position, each of the recording media is divided into a predetermined number of recording areas, and the recording medium corresponds to an arbitrary recording area with respect to the recording medium. Making the head on-track based on the read position information; and determining an off-track state of the corresponding head based on the position information read from the recording area other than an arbitrary recording area of the recording medium. Obtaining the correctness of the position information, and repeating the above steps for all the recording areas of the recording medium to obtain the correctness of all the position information. Obtaining only the defective position data or all the position data of the correct / incorrect data of the position information; Obtaining and storing all of the position data or only the defect position data, and a defect position detection method for a storage device. 3. A predetermined number of heads read out position information recorded on a predetermined number of recording media from a predetermined number of recording media, and based on the position information, read the position information on the recording medium. A seek control method for a storage device for positioning and following a target position, wherein a seek path of the head is predicted before a seek is started based on position data or defect position data of the recording medium stored in claim 1 or 2. Determining whether or not there is a defect position in the seek path; and, when having the defect position in the seek path, selecting a head other than the corresponding head and reading the position information. Performing a seek operation; and returning the head selection to the original corresponding head after the seek is completed. Method. 4. A predetermined number of heads read out position information recorded on a predetermined number of recording media, and the head reads the position information on the recording medium based on the position information. A seek control method for a storage device for positioning and following a target position, wherein a seek path of the head is predicted before a seek is started based on position data or defect position data of the recording medium stored in claim 1 or 2. Determining whether a defect position exists in the seek path; and, when the seek path has the defect position, extracting the defect position in the seek path and setting a corresponding extraction position. Starting the seek of the corresponding head, and actually measuring the defect position by reading out the position information, and when the head is located at the defect position. , Seek control method of a storage device characterized by including a step of performing a seek operation using information of the extracted position the setting. 5. A predetermined number of heads read out position information recorded on a predetermined number of recording media from the predetermined number of recording media, and based on the position information, read the position information on the recording medium. A seek control method of a storage device for positioning and following a target position according to claim 1 or 2, based on the position data or defect position data of the recording medium stored in claim 1 or 2, and Predicting and determining whether a defect position exists in the seek path; and, when the seek path has the defect position, starting a seek to make the defect position absent in the seek path. Adjusting the timing of: and performing a seek operation of the head at the adjusted timing. Control method.