JPH09293344A - Disk unit - Google Patents

Abstract

(57) An object of the present invention is to improve reliability and throughput in data processing for an ID-less type disk format. A servo sector position prediction counter that counts an external clock 41 during disk rotation to predict a servo block position on a track, and an SSA register 45 that predicts a servo block address based on this counter value. In the servo block of the medium, the servo block address is recorded over the track, and the SS
The predicted address of the A register 45 and the address read from the servo block on the medium to the CSSA register 39 are compared by the SSA verification circuit 47, and if they match, the predicted address is regarded as valid and the data block located after the servo block is compared. The address is obtained, and it is further determined whether or not the data block is a processing target. If the address is correct, data recording / reproducing operation for the processing target data block is performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk device, and more particularly to a technique effectively applied to a disk device or the like for increasing the storage capacity of a medium by reducing various control information in an information recording format.

[0002]

2. Description of the Related Art In recent years, the performance and size of computers have been improved, and data storage devices such as disk devices, especially magnetic disk devices using a magnetic disk as a disk medium, have a smaller size, a larger capacity and a higher performance. Is strongly demanded. In response to this demand, attention is focused on a method for increasing the capacity by improving the efficiency of the recording format of the medium.

As an example of this approach, in a conventional disk device, there is a method of deleting (omission) an ID area provided for identifying a sector, as described in, for example, Japanese Patent Laid-Open No. 5-174498. (Hereinafter, this method is referred to as "IDless method").

FIG. 7 shows an example of a possible disc format when the IDless method is used.
Hereinafter, the configuration of this format will be described. The disk format is composed of a servo sector (SSCT160) provided for controlling the position of the head for recording / reproducing data on the recording medium and a data sector (DSCT17) provided for storing user data. Broadly divided. The servo sectors are, as shown in SSCT example 1, AGCG18, SVMK19, IDXMK20 / S.
It is composed of CTMK21, CYL22, POS25, and ISG26. The AGC 18 is provided to adjust the read gain of servo information, and the SVMK 19 is an area provided to detect the head position of the servo sector.

Further, the IDXM20 / SCTM22 is
The CYL 22 is an area provided for identifying the beginning of a track or a sector, and the CYL 22 is an area for storing a cylinder number (track number). The POS 25 stores detailed head positioning information between the cylinders, and controls the detailed positioning operation (settling) and the following operation of always positioning the head on the target cylinder (following). used. IS
G26 is an area provided to absorb the rotational fluctuation of the disk.

On the other hand, the data sector 17 adopts a format in which the recording density is constant over the inner and outer circumferences of the disk, and when the servo sector is included therein (DS
The structure differs between (CTB) and when not including (DSCTA). DSCTA17 is ISG26, PLO27, BS
28, DATA29, ECC30, PAD31. The ISG 26 is an area provided for absorbing the rotational fluctuation of the disk as described above. PLO27
Is an area provided for clock synchronization with the read data, and BS 28 is an area provided for detecting the timing of conversion from serial data to parallel data. DATA 29 is an area for storing user data, and ECC 30 is a read D
When the ATA 29 has an error, it is an area provided for correcting the error. The DSCTB17 is basically a format in which the SSCT160 is inserted in the DSCTA, but after the SSCT160, the PL is re-set.
O27 and BS28 are arranged. This is when reading
This is because the read process is interrupted once when passing through the SSCT 160, and therefore it is necessary to perform clock synchronization and byte synchronization again in order to perform the read process again.

In the ID-less method, since the data sector 17 does not have an ID portion storing the data sector address (DSA), the data sector address (DSA) is obtained using the servo sector address (SSA23) of the servo sector 160. The servo sector address (SSA23) is
Servo sector 160 including the index mark 20
Can be obtained by incrementing the address by 1 each time the sector mark 21 of the subsequent servo sector 160 is detected with the address of 0 as 0.

Once the SSA 23 is obtained, the DSA corresponding to the SSA 23 can be obtained using the address conversion table. This address conversion table has a servo sector 1 arranged in a track as a unit.
It can be easily created from the ratio of 60 and the number of data sectors 17.

[0009]

In the above IDless method, in order to detect the address of the data sector 17,
It is necessary to correctly detect all of the index mark 20 and the sector mark 21 stored in the servo sector 160, and the servo mark 19 indicating the head position of the servo sector 160. False detection of any one of these,
Alternatively, when a defective servo sector that cannot be detected (missing) occurs, the above-mentioned servo sector address (SSA
23) cannot be detected correctly, and there is a possibility that user data may be destroyed by erroneous writing or erroneous read data may be transferred to the host computer. If the defective servo sector occurs in the servo sector immediately after the index, accurate sector recognition becomes almost impossible in the tracks after the defective servo sector. Further, after the seek is completed, the sector cannot be recognized unless the index mark is waited, and the throughput (the amount of data that can be recorded / reproduced / transferred per unit time) is deteriorated due to the waiting for rotation.

To solve these technical problems, in the conventional technique, as shown in SSCT example 2, the SSA 23 is stored in the servo sector 160, and the SSA 23 in the servo sector 160 where the head is actually located is stored. A method of directly reading and detecting is shown. However, in this method, if the read SSA23 is incorrect, the servo sector address (SSA23) cannot be detected correctly as described above, user data is destroyed, or incorrect data is transferred to the host computer. Will cause a malfunction.

In the above-mentioned conventional technique, the SSA23
The error detection code such as CRC24 is added to the servo address including
Although a method of checking whether or not 23 is erroneous is also shown, when an error that cannot be detected by the CRC 24 occurs, the same malfunction is caused. Furthermore, in CRC, G
Since RAY CODE cannot be generated, SSA23, C
The RC24 can be read and the servo sector address can be recognized only after the head is completely positioned on the track. Further, when the recording density (track density) in the radial direction of the disk is improved, GR is affected by the adjacent tracks.
There is a possibility that the read error occurrence rate of the CRC24 part which is not the AY CODE is deteriorated. When a CRC error occurs, rotation waiting is caused by a retry operation for servo sector address recognition, resulting in deterioration of throughput.

It is an object of the present invention to prevent data destruction and data misreading due to erroneous recognition and undetectability of control information in a recording format on a disk medium, and improve operating performance and reliability. To provide a simple disk device.

Another object of the present invention is to make it possible to increase the data recording capacity by reducing the control information in the recording format of the disk medium and to maintain and improve the reliability of the data recording / reproducing operation. To provide a disk device.

Still another object of the present invention is to make it possible to increase the data recording capacity by reducing the control information in the recording format of the disk medium and maintain and improve the throughput in the data recording / reproducing operation. To provide a disk device.

Still another object of the present invention is to detect the target data recording / reproducing area by accurately recognizing the relative position of the head with respect to the disk medium regardless of the operation mode such as seek or on-track. An object of the present invention is to provide a disk device that can perform various operations at high speed.

Still another object of the present invention is to realize various positioning control operations by accurately recognizing the relative position of the head with respect to the disk medium regardless of the operation mode such as seek or on-track. It is to provide a possible disk device.

[0017]

DISCLOSURE OF THE INVENTION A disk device according to the present invention is a disk medium in which servo blocks and data blocks are arranged in a mixed manner on tracks set on a recording surface, and data is recorded / recorded on the disk medium. In a disk device including a head for reproduction, a counter that is counted by a desired clock signal and the value of this counter are not limited to the case where the head is positioned on the target track, and even during seeking, the disk medium A means for predicting a servo block position on a track, a means for predicting a first servo block address for identifying the servo block by the predicted servo block position, and a servo block for identifying the servo block on the servo block all the time during rotation. For storing a second servo block address for executing the servo block A second servo block address read al, comparing the first servo block address predicted by the counter values, and to and a means for determining if both servo block addresses match.

Further, when the second servo block address read from the disk medium and the first servo block address predicted by the counter value match, the second servo block address is placed after the servo block from the servo block address. Means for obtaining the data block address of the obtained data block, means for determining whether the data block having the obtained data block address is the data block to be processed, and whether the head is positioned on the target track Means and means for writing and reading data to and from the data block to be processed when the data block is to be processed and is positioned on the target track.

Further, a counter used for prediction of the servo block and a verification means for verifying the operation of each prediction means are provided.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing an example of the configuration of a servo control unit in a disk device according to an embodiment of the present invention, and FIG. 2 is a timing chart showing an example of the operation of the servo control unit. 3 is a conceptual diagram showing an example of the configuration of servo sectors provided on the disk medium of the disk device of the present embodiment, and FIG. 4 is a conceptual diagram showing an example of arrangement of servo sectors on the disk medium of the disk device of the present embodiment. 5 is a conceptual diagram showing an example of the overall configuration of the disk device of the present embodiment, and FIG. 6 is a flow chart showing an example of the operation of the disk device of the present embodiment.

First, the overall configuration of the disk device 1 of the present embodiment will be briefly described with reference to FIG. For example,
The disk medium 2 in which tracks (not shown) are concentrically arranged is rotated by being supported by a spindle 1a which is rotationally driven by a motor (not shown). The R / W head 3 for recording / reproducing data to / from the disk medium 2 is
Head arm 1c swinging around the pivot shaft 1b
The head arm 1c is fixed to the tip end of the
It is controlled by the voice coil motor 1d. That is, a positioning operation such as a seek operation for moving the R / W head 3 in the radial direction of the disk medium 2 and a following operation for causing the R / W head 3 to follow a specific track are performed by the swinging operation of the head arm 1c. Done.

The R / W head 3 is connected to the data processing device 7 via the R / W amplifier 4 and the signal processing device 5. The voice coil motor 1d is connected to the data processing device 7 via the motor driver 11.

The data processing device 7 includes a drive I / F control unit 8, a buffer control unit 9, a host I / F control unit 10, a data buffer 14, an ECC control unit 6, and a servo control unit 1.
2. The CPU 13 for controlling the whole and the like.
The signal processing device 5 extracts the read data pulse 34 from the read data read from the disk medium 2 and supplies it to the servo control unit 12.

In the case of the present embodiment, as the recording format in the disk medium 2, a sector servo system is adopted in which a data sector in which normal data is stored and a servo sector in which servo information is stored are mixed in a track. There is. Further, in order to make the bit recording density uniform over the entire area of the disk medium 2, the longer the track on the outer peripheral side, the larger the number of data sectors included therein.

Furthermore, in the case of the present embodiment, an IDless system is adopted in which each data sector omits the data sector address (ID) for identifying the data sector. Therefore, since the data sector cannot be identified by reading the ID of each data sector, the data sector is identified by identifying the address of the servo sector and obtaining the data sector address from the servo sector address as described later. .

In the case of this embodiment, the servo sector 16
Are arranged radially from the center of a track (medium) provided on the disk medium 2 as illustrated in FIG. That is, the number of servo sectors 16 in each track and the position in the circumferential direction are the same. For the servo sector address, the servo sector 16 including the index mark is set as the reference servo sector 16A indicating the start point of the track, and the servo sector address is set to "0". As shown in FIG. 4, servo sector addresses are sequentially defined in the order in which the R / W head 3 passes the servo sector 16 in the rotation direction of the disk medium 2. Each servo sector 16 defines the same servo sector address from the inner track to the outer track.

FIG. 3 shows an example of the structure of the servo sector 16. Unlike the data sector 17, the servo sector 16 records widely up to the track boundary. The SSA 32 (servo sector address) in each of the radially arranged servo sectors 16 has the same value from the inner track to the outer track, and is therefore recorded in a continuous pattern even at the track boundary. In this way, each servo sector 16
By recording the SSA 32 in the SSA 32, it is possible to read the SSA 32 in the servo sector 16 even when the R / W head 3 is located at the track boundary or during seek. Other components are the servo sector 1 in the conventional sector servo type disk device illustrated in FIG.
Since it is the same as 6, the description is omitted.

On the other hand, the format of the data sector 17 is, for example, DSCT as illustrated in FIG.
A17, DSCTB17, etc. can be adopted.
That is, DSCTA 17 shows a configuration example of a data sector which is not divided by the servo sector 16, and D
The SCTB 17 shows a configuration example of the data sector divided by the servo sector 16.

The operation of each block of the disk device of this embodiment will be described with reference to FIG. 5 by taking the data read operation in the IDless format system as an example. CP
U13 calculates the address on the recording medium of the data sector 17 in which the data requested by the host computer 15 is stored. The servo control unit 12 and the motor driver 11 read / write on the track where the data sector 17 exists.
The W head 3 is moved and positioned. Control information for this purpose is recorded in the servo sector 16 and is read by the R / W head 3 for each servo sector 16 to read the R / W.
The read data pulse 34 is sent to the servo control unit 12 via the amplifier 4 and the signal processing device 5. At the same time, the servo control unit 12 obtains the data sector address where the R / W head 3 is located and sends it to the drive I / F control unit 8. The drive I / F control unit 8 determines whether the data sector address is the requested data sector 17. If the data sector 17 is a required data sector, the R / W head 3 reads the data sector, and the read data is sent to the drive I / F control unit 8 via the R / W amplifier 4 and the signal processing device 5 and converted into parallel data. To be done. The data is stored in the buffer controller 9,
The error is detected and corrected by the ECC controller 6 via the data buffer 14 and the host I / F controller 10 and sent to the host computer 15.

Next, referring to FIG. 1, an example of the configuration and operation of the control block portion for performing sector recognition in the servo control unit 12 will be described in detail.

In FIG. 1, a servo sector position prediction counter 42 counts an input pulse from an external clock 41 such as an oscillator, predicts each servo sector position, and outputs an SSA_INC signal 50 at each timing. The servo sector position prediction is based on the servo mark search operation start timing for reading the servo sector (SRVMKS given to the servo mark detection circuit 35 by the servo control sequencer 40).
It is necessary to obtain the RCH 52), and the servo mark search operation start timing and the output timing of the SSA_INC signal 50 may be common.

The SSA register (SSA_REG) 45 holding the predicted servo sector address is updated by the SSA_INC signal 50 for each servo sector predicted position by the servo sector position prediction counter 42. In the present embodiment, the servo sector address is defined so that the address of the subsequent servo sector 16 is incremented by 1 with the reference servo sector 16A including the index mark as the reference (0). Therefore, the SSA register is determined for each servo sector predicted position. Increment by 45. Further, the SSA register 45 is replaced by the MAX_SSA register 43.
When the number of servo sectors stored in (MAX_SSA_REG) is reached (matches the maximum servo sector address value), the next servo sector 16 is the reference servo sector 16A including the index mark, so the SSA register 45 at the next servo sector predicted position. Is updated to "0". The above operation starts the operation after the rotation is stabilized at the time of starting the disk, and after the start of the operation, during the normal rotation of the disk, the seek of the servo sector position is always performed even if the processing for the data sector 17 is not performed, such as during the seek operation. Predicts the servo sector address. This allows SSA
The register 45 stores the expected value of the address of the servo sector 16 through which the R / W head 3 passes. The value stored in the SSA register 45 is compared and verified by the SSA 32 read from the servo sector 16.

SSA3 read from the servo sector 16
2 is stored in the current servo sector address register (CSSA_REG) 39 at the timing of CSSALTEN 55 output from the servo control sequencer 40 upon detection of the SVMKF 53. The SSA 32 in the servo sector 16 can be read during a seek in which the R / W head 3 is not positioned on the track, and the SSA 32 is read every time the servo sector 16 is passed during the seek as well as during the on-track, and the CSSA register is read. It stores in 39.

The SSA verification circuit 47 uses CSSALTEN.
SSAMPEN 56 is output from the servo control sequencer 40 triggered by the output of SSA 55.
The register 45 and the CSSA register 39 are compared and verified, and the set input of the RS flip-flop 47a in the subsequent stage is asserted to output SSA_EN51. The RS flip-flop 47a receives the SSA_INC signal 50 as a reset input and invalidates the SSA_EN51.

The data sector address generation circuit 46 determines the servo sector 16 corresponding to the servo sector address.
Is a circuit for obtaining the data sector address of the data sector 17 following the above by using a conversion table or the like. SSA register 4
When the comparison verifications of 5 match, the value of the input SSA register 45 is changed by turning on the SSA enable 51.
Obtain the data sector address. The servo control sequencer 40 controls the above operation. All the above circuits can be accommodated in one LSI, and a small disk device can be realized.

FIG. 2 shows an example of the verification processing timing of the SSA register 45. SS at the servo sector predicted position by the servo sector position prediction counter 42
When the A register 45 is updated (by the reset input of the SSA_INC signal 50 to the RS flip-flop 47a)
The SSA enable 51 is turned off, and the value stored in the SSA register 45 is invalidated once. When reading the servo sector,
The SSA register 45 in which the read value of the SSA from the disk medium 2 is stored is verified, and if they match, the SSA enable 51 is turned on and the SSA register 45 is validated. If they do not match, the SSA enable 51 remains off and the SSA register 45 in the servo sector 16 is invalidated, and sector recognition is not performed. Even if a servo sector is not detected, a sector mark is not detected, or a defective servo sector that causes an SSA read error occurs, it is irrelevant to the updating operation of the SSA register 45 by the servo sector position prediction counter 42.
The SSA register 45 stores the expected value that is constantly updated at the servo sector predicted position. That is, in the defective servo sector, the verification result of the SSA register 45 becomes unacceptable (NG), the SSA register 45 is invalidated and the sector recognition is not performed, and the SSA register 45 maintains the correct value. Therefore, the SSA comparison verification in the normal servo sector 16 after the defective servo sector is not affected, and the target sector can be recognized if the SSA comparison verification in the target servo sector 16 matches.
There is no throughput deterioration such as generation of waiting for rotation due to this defective servo sector.

Further, the servo sector position prediction counter 42
Also, an abnormality in the SSA register 45 is always verified, even during seeking, and therefore it can be determined by occurrence of verification disagreement or the like. For example, two or more servo sectors 1 in succession
6, if the verification mismatch continues, or if the index mark 20 cannot be detected in the servo sector 16 with the SSA register 45 = "0", the SSA register 45 = "0".
When the index mark 20 is detected in the servo sector 16 other than the above, an error may be generated in such a case.

In order to further improve the reliability, as shown in FIG. 3, an error detection code EC is added to a part of the servo sector 16.
S added with 33 and stored in CSSA register 39
You may check SA32. However, CYL2
2 and the error detection code for SSA32 are GRAY
Since CODE cannot be generated, it is impossible to read or check the error detection code during seek. Therefore, the error detection code (EC) for SSA32 only
It is desirable to add 33. This is because the error detection code 33 and the SSA 32 are the same in each track in the servo sector 16 having the same address, so that the error detection code 33 can be read and checked during seek.

In the disk device of this embodiment, SS
Since the A register 45 always indicates the head position, C
It is also possible for the PU 13 to recognize the position of the R / W head 3 by the SSA register 45 and perform various and intelligent sector control in consideration of rotation waiting and the like, and it is possible to further improve throughput.

That is, by referring to the SSA register 45, the current position of the R / W head 3 in the track can be always known regardless of whether it is seeking or on-track. By controlling the time, for example, when accessing a plurality of tracks, various controls such as changing the access order of each track and the data sector 17 in the track so as to minimize the total rotation waiting time. Can be easily realized.

During operation, a defective servo sector occurs and SS
Since the A32 cannot be read, the SSA register 45
If the verification fails, the data sector 17 obtained from the SSA register 45 cannot be recognized and the data sector 17 cannot be read. However, the verification operation of the SSA register 45 by the CSSA register 39 is invalidated, The data sector 17 can be recognized by recognizing the servo sector address (SSA 32) only by the SSA register 45, which is updated by the servo sector position prediction counter 42, and can be used as one of recovery means for reading user data.

Similarly, the SSA 32 is assigned to each servo sector 16.
May be recorded, and the servo sector address may be recognized only by the SSA register 45 updated by the servo sector position prediction counter 42. In this case, in order to improve reliability, for example, the servo sector position prediction counter 4
2 and the SSA_REG update control circuit 44, a preparity check circuit is added, the servo sector position prediction counter 42 and the SSA_REG update control circuit 4 are added.
4 is provided with hardware malfunction detecting means such as duplication, or by software malfunction detecting means such as once confirming that the index mark 20 is detected in the reference servo sector 16A. Verify the SSA register 45. Since this method does not require recording the SSA 32 in each servo sector 16, the format use efficiency is further improved and the circuit configuration is further simplified.

As described above, the disk device according to the present embodiment is provided with the servo control method for always performing the servo sector address recognition operation regardless of the on-track even during the seek operation. , It is superior in throughput as compared with the conventional method of performing the sector recognition operation. That is, by always recognizing the servo sector address (SSA32), the data sector 17 has already been recognized at the time when the seek is completed, and the RD / W is immediately recognized for the target data sector 17.
It is possible to perform an R operation.

As described above, according to the disk device of the present embodiment, when performing data processing for the disk format adopting the ID-less method, the user data is destroyed due to the erroneous detection of the servo sector address 32 and the undetectable servo sector address 32. , And erroneous data transfer are prevented, and the servo sector address 32 is recognized independently of on-track, so that the reliability and performance of the disk device and the servo control system can be improved.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above-mentioned embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say.

For example, the disk device is not limited to a magnetic disk device using a magnetic disk as a disk medium, but can be widely applied to general disk devices using an optical disk, a magneto-optical disk, etc. as a disk medium.

[0048]

According to the disk device of the present invention, it is possible to prevent data destruction or data misreading due to erroneous recognition or undetectability of control information in the recording format of the disk medium, and to improve operating performance and reliability. Can be improved,
The effect is obtained.

Further, there is an effect that both the increase of the data recording capacity by reducing the control information in the recording format of the disk medium and the maintenance and improvement of the reliability of the data recording / reproducing operation can be achieved at the same time.

Further, it is possible to achieve both the increase of the data recording capacity by reducing the control information in the recording format of the disk medium and the maintenance and improvement of the throughput in the data recording / reproducing operation.

Further, regardless of the operation mode such as seek or on-track, it is possible to accurately recognize the relative position of the head with respect to the disk medium and to detect the target data recording / reproducing area in various and high speeds. You can get the effect.

In addition, regardless of the operation mode such as seek or on-track, it is possible to accurately recognize the relative position of the head with respect to the disk medium and realize various positioning control operations. .

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of a configuration of a servo control unit in a disk device according to an embodiment of the present invention.

FIG. 2 is a timing chart showing an example of the operation of the servo control unit in the disk device according to the embodiment of the present invention.

FIG. 3 is a conceptual diagram showing an example of a configuration of servo sectors provided in a disk medium of a disk device according to an embodiment of the present invention.

FIG. 4 is a conceptual diagram showing an example of arrangement of servo sectors in a disk medium of a disk device according to an embodiment of the present invention.

FIG. 5 is a conceptual diagram showing an example of the overall configuration of a disk device that is an embodiment of the present invention.

FIG. 6 is a flowchart showing an example of the operation of the disk device according to the embodiment of the present invention.

FIG. 7 is a conceptual diagram showing an example of a possible conventional disc format using an IDless system.

[Explanation of symbols]

1 ... Disk device, 1a ... Spindle, 1b ... Pivot shaft, 1c ... Head arm, 1d ... Voice coil motor,
2 ... Disk medium, 3 ... R / W head, 4 ... R / W amplifier, 5 ... Signal processing device, 6 ... ECC control unit, 7 ... Data processing device, 8 ... Drive I / F control unit, 9 ... Buffer control Parts, 10 ... Host I / F control part, 11 ... Motor driver, 12 ... Servo control part, 13 ... CPU, 14 ... Data buffer, 15 ... Host computer, 16 ... Servo sector (servo block), 16A ... Reference servo sector,
17 ... Data sector (data block), 18 ... AGC
G, 19 ... Servo mark, 20 ... Index mark,
21 ... Sector mark, 32 ... Servo sector address, 3
3 ... Error detection code, 34 ... Read data pulse, 3
5 ... Servo mark detection circuit, 39 ... CSSA register,
40 ... Servo control sequencer, 41 ... External clock, 4
2 ... Servo sector position prediction counter (first prediction means), 43 ... MAX_SSA register, 44 ... SSA_
REG update control circuit, 45 ... SSA register (second predicting means), 46 ... Data sector address generation circuit, 47
... SSA verification circuit (comparing means), 47a ... RS flip-flop, 50 ... SSA_INC signal, 51 ... SSA enable.

Claims (5)

[Claims] 1. A disk medium, a head for recording and / or reproducing data on and from a recording surface of the disk medium, and a head positioning mechanism for positioning the head at an arbitrary position on the recording surface. A disk device including a recording / reproducing operation of the head and a control unit for controlling the head positioning mechanism, wherein the disk medium is a plurality of data in which the data is stored in a track set on the recording surface. Block and
Servo blocks that store positioning control information used to control the positioning operation of the head with respect to the recording surface are mixedly arranged, and the control unit is reset at a specific position during rotation of the disk medium. A counter, a first predicting unit that predicts a position of the servo block on the track based on the value of the counter, and a servo block that identifies the servo block for each position of the servo block predicted by the first predicting unit A second prediction means for predicting the first servo block address of the disk device. 2. The disk device according to claim 1, wherein
In the servo block of the disk medium, a storage area for a second servo block address for identifying the servo block is provided across a plurality of the tracks, and the control unit is in the process of seeking and Means for reading the second servo block address via the head regardless of any on-track; the first servo block address predicted by the second predicting means; Comparing means for comparing the second servo block address read from the storage area with each other to determine whether or not they match each other; and the subsequent data from the first or second servo block address. Means for obtaining a data block address for identifying a block, and a disk device. 3. The disk device according to claim 2, wherein
The control unit obtains a data block address of the data block located after the servo block address from the servo block address when the first and second servo block addresses match each other; A step of determining whether or not the data block of the data block address is a data block to be processed; and if the head is located on the target track when it is determined to be the data block to be processed, And a step of performing at least one of writing and reading of the data with respect to the data block, and a control logic for executing the step. 4. The disk device according to claim 2, wherein
If the first and second servo block addresses do not match or the second servo block address in the servo block cannot be read and the target data block becomes unrecognizable, the control unit may Invalidating the comparison result by the comparison means, and obtaining the data block address of the data block arranged after the servo block from one of the first and second servo block addresses; A step of determining whether or not the data block is a processing target data block; and, if the determination results match and the head is positioned on the target track, the processing target data block To write or read data to and from Disk apparatus characterized by comprising a control logic that. 5. The disk device according to claim 1, wherein
The control unit confirms an index mark set in the specific servo block in the track so that the index mark is detected only once per one rotation of the disk medium, and the counter, and the counter. One or both of second verifying means for detecting malfunction of at least one of the predicting means for predicting the first servo block address are provided, and the verification of the first servo block address predicted by the predicting means is performed. A disk device characterized by performing.