JP3392311B2 - Data recording medium formatting method and disk device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of formatting an auxiliary storage device of an electronic data processing device having a rotary recording / reproducing medium, such as a disk device, and more particularly to a dual method having a write head and a read head independently. The present invention relates to a formatting method suitable for a disk device using a head.

[0002]

2. Description of the Related Art In recent years, disk devices have been rapidly reduced in size, increased in speed, enhanced in function and reduced in price. In particular, the speed of increasing the capacity of magnetic disk devices is rapidly increasing.
This is realized by an increase in the number of user data recording media per device and an increase in the user data recording amount (area recording density) per unit area of the medium. This areal recording density is
The increase was 1.4 times that of the previous year. But here 1-
Since two years ago, the areal recording density has been increasing about twice per year, and the rate of increase has become steep.

This was realized by MR (Magneto Regis).
development of a new head called PRence (P.
It is the development of new signal processing technology such as artial Response Maximum Likelihood. As a result, the thin film head (Inductiv
e head) and a read-only MR head are integrated into a dual head.

By the way, in this dual head, since the two heads of the write head and the read head are integrated, it is very difficult to accurately match the electrical centers of both heads in the track direction (radial direction).
For this reason, when a format format in which a dedicated ID area is provided for each sector, which is a conventional format format, is adopted, in the track direction center of both the ID area and the user data area, according to the write or read conditions, It is not possible to align each head with high precision. Therefore,
There is a problem that the density in the track direction cannot be increased above a certain level.

Further, in the case of the MR head, it takes time for the output of the MR head to stabilize when switching from the data write operation to the read operation. Therefore, when an ID exists in each sector as in the conventional case, reading of the ID and writing of the data area are repeated at the time of writing data, so that there is a problem that the user data of the medium cannot be effectively used in the recording area.

In order to solve these problems, a format for deleting the ID area (hereinafter referred to as sector IDless format) has been proposed. Then, a means for identifying the sector is devised by utilizing the information in the servo area. A technique related to these is disclosed in Japanese Patent Laid-Open No. 5-174
498, JP 7-211000 A, JP 7-211006 A, JP 7-219716 A and the like.

[0007]

In the above prior art, the data sector number is specified by using the track number, head number, and servo sector number stored in the servo area in order to specify the data sector.

However, it is necessary to write the servo information on the medium with an expensive servo track writer. At present, in order to improve the usage efficiency of the servo track writer, the same value is simultaneously written on the medium in the cylinder direction by a plurality of heads. When the writing is performed, the writing time is doubled by the number of heads mounted in the disk device, and the use efficiency of the servo track writer is reduced.

Further, in the above-mentioned conventional technique, since the sector ID area is eliminated, the information of the servo area is used for specifying the sector number. However, since the dual head is used, the same servo is used at the time of data writing and reading. It is impossible to position the read head at the center of the area in the track direction. This is because the read head is largely displaced from the center of the user data area in the track direction at the time of reading the data, and the reliability of the read data is deteriorated. Therefore, both the servo area and the user data area must be read with some offset, and the reliability of the data deteriorates.

The present invention provides a conventional sector I as described above.
In the D-less format, a formatting method capable of preventing deterioration in utilization efficiency of a data storage medium without deteriorating reliability regarding sector identification, a disk device controller and a disk device implementing the method, and a method thereof The purpose is to provide a formatted recording medium.

[0011]

In order to achieve the above object, in the format of the data recording medium according to the present invention, a writing ID portion corresponding to the servo area is provided. The writing ID portion is, for example, immediately before the corresponding servo sector or 1
Place it immediately after the previous servo area.

Further, an error correction code capable of error occurrence detection and correction may be added to the write ID section. Further, the write ID section may store information indicating a cylinder number, a head number, and a servo sector number, and the servo area may have only common information such as a cylinder number and a servo sector number. Further, the writing ID portion does not necessarily have to be provided for each servo area, and may be configured to add only a typical servo area.

Further, the read ID portion may be recorded in the user data. Further, the information stored in the read ID part may be a target of an error correction code for error detection and correction of user data.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION A case where an embodiment of the present invention is applied to a magnetic disk device will be described below with reference to the drawings. Here, the magnetic disk device may be realized by a peripheral device such as a floppy disk device, a magneto-optical disk device, an MD device, or the like, as a matter of course.

FIG. 1 shows the format configuration of the disk device according to the present embodiment. In this embodiment, the write I
A case will be described where the D (W-ID) 111 is arranged immediately before the servo area 104 and the read ID (R-ID) 112 is arranged in each data sector.

The writing ID area need not be provided for each servo. The time during which this write ID area can be read in order to specify the format efficiency and the portion when writing data becomes the overhead of the transfer time until the start of writing. The designer may decide the position of the writing ID area in consideration of this.

Now, consider the case where the dual head 106 including the write head 107 and the read head 108 passes through the sectors 101, 102 and 103 as shown in FIG. Further, the head positioning method will be described using the data surface servo method. This servo area 104 is
Track number area 1 for knowing the track number of the head
09 and a position signal area 110 for knowing a slight deviation of the head with respect to the track.

The writing ID area 111 is provided with an ECC 114 for detecting and correcting an error in this portion. Further, in each data area 105, a read I
It is assumed that the D information 112 is included. This R-ID
112 is a data area 1 together with the user data 115.
Error correction code E provided at the end of 05
The target of CC116.

In this embodiment, at the time of writing data, the read head 108 reads the writing ID 111 and confirms whether or not there is an error in this ID area. If there is, the correction operation starts, but since the servo area 104 is next, the correction operation can be performed by utilizing the transit time of the servo area 104. Therefore, it is not necessary to provide the recording medium with an interval corresponding to the time until the correction is completed, and the overhead can be reduced.

When the above-mentioned error correction is normally completed and the positioning of the head is normal as a result of passing through the servo area, the cylinder number, head number and servo sector number written in the read write ID 111 are written. Is checked by the disk device controller. When these values are normal, the sector number and position are specified from the servo sector number by a conventional method such as a table method, and when the relevant sector is reached, data writing is executed.

Further, at the time of reading data, after confirming that the track is the corresponding track by reading the servo area 104, the data in the data area 105 is read into the buffer of the disk device. At this time, by confirming the read ID information 112 embedded in the data area 105 after the ECC processing is completed, it is confirmed whether or not this sector is good data to be transferred to the host. With this configuration, correct data can be transferred to the host.

According to the format of this embodiment, in the disk device equipped with the dual head, the sector I
Even in the D-less format, the information for identifying the sector can be confirmed from the recording medium at the time of writing or reading the data, so that the disk device having the same reliability as the conventional one can be realized.

Further, in this embodiment, the writing ID 1
Since 11 is arranged immediately before the servo area 104, the overhead of the recording medium due to the correction time when the error of the writing ID 111 occurs can be hidden by the servo area.

Further, according to the present embodiment, the write ID 111 is also applied to the disk device which employs the dual head including the MR head, which has a peculiar property that it takes time from the writing operation to the reading operation.
Is continuous in the servo area, the overhead of the medium does not increase compared to the conventional case.

Next, the write ID 1 according to the present embodiment
The correction operation 11 and its timing will be described with reference to FIG. Here, consider a case where a burst error occurs in the write ID 111. Further, the error detection / correction circuit provided in the disk device is a writing I
ID-ECC processing unit for D and D for user data target
The case where each has an ata-ECC processing unit will be described.

When writing data, the dual head 10
6 starts reading the writing ID 111,
First, the ID-ECC processing unit is activated ((a) in FIG. 2). If an error occurs at the time when the reading of the writing ID 111 is completed, ID-EC
The C processing unit starts the error correction operation ((b) in FIG. 2).

Normally, the write ID 111 is 30 Byte.
Since it is about e, it is sufficient for correction to have the same number of bytes. Also, the servo area 104 is usually 10
Since the size is 0 bytes or more, as shown in FIG. 2B, it is sufficiently possible to complete the correction operation while passing through the servo area 104.

Therefore, according to the present embodiment, by disposing the writing ID 111 immediately before the servo area 104,
Wasted medium space due to ID correction time (overhead)
It is possible to realize a disk device with good medium efficiency without the need to prepare.

Next, an example of the arrangement of each area in the track direction and the offset amount of each head in that arrangement in the format of the embodiment of FIG. 1 will be described with reference to FIG. Here, α is a read head (R head) 10
8 shows the head-to-head tolerance of the write head (W head) 107 in the track direction.

In this example, as shown in FIG. 3, the center of the write ID area 111 in the track direction and the servo area 10 are arranged.
4 is arranged so that the deviation from the track center is 1 / 2α, and the read head 108 is set to + 1 / 2α with respect to the servo area center (TRK center) during the data writing operation and the data reading operation of the dual head 106. -1 /
The operation is performed by offsetting each by 4α.

According to the configuration of this example, data can be read and written with the offsets shown in the table 301 in FIG. In particular, the read head 108 at the time of reading data
There is an effect that a suitable medium format can be realized when it is desired to minimize the offset.

Another example of the arrangement of each area in the track direction in the format of the embodiment of FIG. 1 and the offset amount of each head in that case will be described with reference to FIG. Here, α is defined as in the above. In this example, the write ID area 111 and the servo area 1
04 are arranged so that their centers in the track direction coincide with each other, and the read head 108 is 0 (matched) and −1 / 2α with respect to the center of the servo area during the data write operation and the data read operation by the dual head 106. Operate by offsetting each.

According to the configuration of this example, data can be read / written with the offsets shown in the table 401 in FIG. The configuration of this example has an effect that a medium format suitable for the case where the offset of the read head 108 at the time of writing data is desired to be minimized can be realized.

Next, another embodiment of the present invention will be described with reference to FIG.
Will be described with reference to. 5, the same components as those in the embodiment of FIG. 1 are designated by the same reference numerals, and detailed description of the components will be omitted.

In the format according to the present embodiment, the write ID 111 is arranged immediately after the servo area immediately before the corresponding servo area. That is, sector n
Writing ID 111 for +1 servo area 104
Is provided immediately after the servo area 104 of sector n.

According to the format configuration of this embodiment,
It is not necessary to prepare the circuit stabilization time from writing to reading, which is peculiar to the dual head, and the medium overhead is not increased. Furthermore, according to the present embodiment, 1
The correction time 500 of the writing ID can be secured within the servo cycle time, and the error correction can be performed by the correction means realized by software without using the hard logic correction circuit, and the ID-ECC correction processing can be performed. This has the advantage of reducing the dedicated hardware of some parts and is suitable for cost reduction.

Next, an example of the detailed structure of the format in the embodiment of FIG. 1 is shown in FIGS.
In this example, the track format (a) is composed of a plurality of servo areas 104, the write ID 111 is provided immediately before the servo areas 104, and each data area 10
A case in which the reading ID 112 is provided in No. 5 will be described.

A detailed servo area format is shown in FIG. 6 (b). Similar to the known conventional format, Servo Sync 604 for circuit synchronization, Servo Mark 605 for taking subsequent decoding timing, and INDEX Sector Mark indicating whether the corresponding servo area is the head servo
606, Cylinder Address 607 indicating the cylinder number,
Burst A, B, for delicate positioning of the head,
C, D (611 to 614), and GAP 615 that becomes a boundary with the next area follow. Here, the SSA 609 indicating the servo sector number and its check code CRC 610 may be optional.

Next, details of the data area format are shown in FIG.
It shows in (c). This is for storing user data. Data Sync 621 for circuit synchronization and Dat for decoding timing.
a Mark 622, R-ID 626 for knowing the sector number at the time of data reading, User Data 6 which is user data
23, ECC 624 for error correction of R-ID and User Data, PAD 625 of R / W circuit delay, GAP
It consists of 615. Note that the R-ID 112 is conceptually captured, sync and mark are not taken into consideration, and the R-ID 626 indicates a specific ID.

Details of the W-ID area format are shown in FIG. 6 (d). The same configurations as those described above have the same names, and the description thereof will be omitted. Here, the cylinder number 633, the head number 634, the servo number 635,
An error check is performed on the FLAG 637 of various control information by the ECC 638.

The R-ID area format is shown in FIG.
As shown in, cylinder number 641, head number 64
2, sector number 643, and FLAG 644.

With the above format, the servo area 104 has the same information on each surface of the storage medium, and the servo track writer enables simultaneous writing by a plurality of heads. As a result, it is possible to reduce the occupied time of the expensive disk device of the servo track writer.

Further, as shown in FIGS. 6D and 6E, in each ID area, it is possible to confirm whether the access location is correct or not by the information read from the recording medium.
It is possible to maintain reliability as in the case with D. In particular, even if another area is accessed due to a circuit error in the disk device, the area is confirmed from the data read from the recording medium, so that the possibility of erroneous writing or erroneous reading can be correctly detected, and the reliability is high. A disk device without sector ID can be realized.

Next, FIG. 7 shows an example of an electronic circuit configuration for realizing a disk device using the sector IDless format to which the present invention is applied.

The disk device 712 according to the present example has an R / W
The circuit 701, the data processing unit 702, the CPU 705, the data buffer 709, the mechanism unit 714, the mechanism control unit 711,
And a flash memory 718. Data processing unit 7
02 functions as a disk device controller, and includes a CPU I / F control unit 704, a drive I / F control unit 703, an ECC processing unit 706,
It has a buffer control unit 707 and a host I / F control unit 710. The mechanical control unit 711 is A /
It has a D conversion circuit 708 and a D / A conversion circuit 717.

The operation of the disk device 712 according to this example will be described below.
An example will be described in the case of standard data read.
Here, consider a case where the disk device 712 and the host 713 are connected via a standard interface.

First, an instruction to read data from the host 713 is sent to the disk device 712 according to the interface protocol. The command transferred to the disk device 712 is received by the host I / F unit 710 in the data processing unit 702 of the disk device 712,
It is sent to the CPU 705 and command interpretation is performed. Then, the CPU 705 starts the work of reading the data of the corresponding sector of the drive, and starts the work of reading the corresponding sector instructed by the host 713. The flash memory 718 is used for online rewriting of programs, storage of defect information of disk devices, and the like.

Here, the mechanical section 714 includes the medium 721, the magnetic head 722, and a VCM for driving the magnetic head.
(Voice Coil Motor) 715, and a spindle motor 716 for rotating the medium. The CPU 70 is provided so that the mechanical section 714 can read the data of the corresponding sector.
The mechanical control unit 711 gives an instruction according to the instruction from 5.

The mechanical control section 711 controls the mechanical section 714 by instructing a motor driver (not shown) from the position signal from the R / W circuit (read channel) 701 to control the magnetic head 722 to the medium 721. Position it in the applicable track. As a result, the data of the corresponding sector is read and the analog signal is read by the read channel 701.
It is converted into a Z (Non Return to Zero) signal. This signal is the drive I / F control unit 7 of the data processing unit 702.
It is taken in by 03.

The read data is sent to the data buffer 709 via the ECC processing unit 706 and the buffer control unit (DMAC) 707 for checking the error of the read data. And ECC
When the processing unit 706 reports that no error has occurred, the read data stored in the data buffer 709 is transferred via the host interface control unit 710.
It is transferred to the host 713.

Here, the read ID is checked by EC.
This is performed by the C processing unit 706. Further, the write processing ID check at the time of data writing is also performed by the ECC processing unit 706 under the instruction of the drive I / F control. With such a hardware configuration, a highly reliable sector ID-less format can be realized.

Next, an example of the servo ID portion control processing for realizing the disk device using the format according to the present invention will be described with reference to the flowcharts of FIGS. 8 and 9.

First, the servo ID (for example, W- in FIG.
It is checked whether the ID area 111) is about to come (step 010). If not, I'll wait.
If it is the scheduled time, it goes to the next process.

Next, this servo ID is 1 for one rotation of the medium.
INDE to know if there is only one INDEX part
It is checked whether or not X PULSE MARK (IDXP MK) has come (step 020). In the case of INDEX, it is checked whether this is within the time required for the recording medium to make one rotation (step 210). If correct, INDE
The value m counting the number of times when X PULSE is continuously wrong is set to 0 (step 220).

Next, since the servo sector number is the head, the servo counter is set to 0 (step 230). If I
If NDEX PULSE does not come within the correct time, the number of abnormal times m is incremented (step 24).
0). Then, it is checked whether or not the number of times is the specified value m ₀ or more (step 250). If it is less than the specified value, the value of the counter will be correct even if the values do not match.
The servo counter of the servo ID is set to 0. If the number of abnormalities is equal to or greater than the specified value, it is determined that the INDEX PULSE is abnormal, the medium rotation speed is abnormal, and predetermined abnormality processing is performed (step 260), and the processing ends abnormally (step 980).

Further, in step 020, INDE
If it is determined that it was not X, SCTER PUL
Since SE (SSCTP) is coming, it is checked whether it is also within the specified time (step 31).
0). If it has, the value n, which is the number of consecutive abnormalities of the servo ID sector, is set to 0 (step 320) and the servo sector counter is incremented by 1 (step 330) because it is normal.

In step 310, the SCTE
When it is determined that R PULSE has not come within the specified time, the abnormal count n is incremented (step 3
40). Then, it is checked whether the number of times is equal to or more than the specified value n ₀ (step 350). If less than the specified value,
Assuming that value is correct, the servo count of the servo ID is incremented by +1 (step 330). If the number of abnormalities exceeds the specified value, that is, SCTER PULSE
If it is abnormal, the INDEX PULSE is determined to be abnormal, and the medium rotation speed is determined to be abnormal and predetermined abnormality processing is performed (step 360), and the processing ends abnormally (step 98).
0).

Next, when the servo counter value and the like are determined to be normal in the above processing, the processing proceeds to step 040.

First, the servo number and its error correction code ECC are read (step 040), and it is determined whether or not an ECC error has occurred (step 050). If an ECC error occurs, it is checked whether the mode is an ECC error correction mode (step 510). If E
If the CC error is ignored, the process proceeds to step 060. When it is determined that the ECC error correction is performed, the process proceeds to step 520, and the ECC error correction operation is performed.

Next, it is checked whether ECC error correction has been completed (step 530). If the correction is successful, the process proceeds to step 060. If it cannot be corrected, the abnormal number O is counted up (step 610). Further, it is checked whether or not the number of consecutive abnormalities exceeds the specified value O ₀ (step 620). If it exceeds the specified value, the servo ID number is abnormal and the mismatch abnormality processing is performed (step 630), and the processing ends abnormally (step 980).
If it is less than the specified value in step 620, the servo count value is used as the servo ID number (step 08).
0). Then, the processing ends (step 990).

In addition, when there is no ECC error,
If the error is corrected correctly, it is checked whether the servo count value and the servo ID number value match (step 060). If it is normal, since the continuous abnormality counter value is counted, the value of the continuous abnormality count O is cleared (step 07
0), the process proceeds to step 080 and the servo count value is used as the servo ID number.

As described above, according to the format of the present invention, INDEX cycle check, servo sector cycle check, servo number counter value and read ID value check can improve reliability. There is an effect. Further, since the correction processing of the read error of the servo ID number is performed during the passage of the servo area, the correction time does not become the overhead of the recording medium.

Further, since the processing in the case where the servo ID and the servo counter value do not match is also considered, the read operation does not need to be a perfect device structure, and the data may be saved. For example, there is also a method of preventing the data destruction of the user by setting the variables m, n, and O indicating the number of continuous abnormalities shown this time to 0 for writing and 5 for reading according to the operation mode. . Also,
A configuration may be adopted in which the specified value is initially set to 0 even at the time of reading, and the specified value is increased if the servo ID cannot be normally processed.

As described above, the servo ID control method can be realized by realizing this processing method. Of course, the method described in the present embodiment is an example, and in addition to this, it is also possible to adopt a method of thinning out one servo ID for two servo areas to improve the format efficiency.

As described in the above embodiments, according to the present invention, even in a disk device equipped with a dual head, which employs a sector IDless format,
Since the servo ID (W-ID area) for writing for specifying the data sector address is provided, the specific reliability of the data sector at the time of writing data can be maintained.

Further, since the write ID is arranged immediately before the servo area and an error correction code is added so that the error can be corrected, even if an error occurs in the write ID, the correction is made by the head in the servo area. It is done when passing. Therefore, it is possible to prevent the overhead of the recording medium from increasing due to the correction time.

Furthermore, since the write ID is arranged continuously with the servo area, the overhead of the recording medium due to the circuit stabilization time required for writing to reading peculiar to the MR head does not increase.

Further, the write ID is not provided in each servo area, but is attached to a typical servo area, so that deterioration of the medium efficiency can be prevented as much as possible.

Further, since the write ID area is provided with the cylinder number, the head number, and the servo sector number, and the servo area is provided with only the cylinder number and the servo sector number which are common information on each medium surface, the servo It is also possible to prevent an increase in occupied time of the servo track writer for writing the area in the disk device.

Further, the read sector ID information is
Since it is included in the user data, it is possible to maintain the reliability of specifying the data sector when reading the data.

Further, since the ID information for reading is the target of the error correction code for detecting and correcting the error of the user data, it has no special error correction code and I
There is also an effect that the reliability of D can be maintained.

[0072]

According to the present invention, in the sector IDless format adopted in the disk device having the dual head, it is possible to prevent the deterioration of the utilization efficiency of the data storage medium without lowering the reliability regarding the sector identification. It is possible to provide a formatting method, a disk device controller and a disk device that implement the method, and a recording medium formatted by the method.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a format configuration of a disk device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing W-ID correction timing in the embodiment of FIG.

3A and 3B are explanatory views showing an example of the arrangement of each area in the embodiment of FIG. 1 and the offset amount of the head at that time.

FIG. 4 is an explanatory diagram showing another example of the arrangement of the regions in the embodiment of FIG. 1 and the offset amount of the head at that time.

FIG. 5 is an explanatory diagram showing a format configuration of a disk device according to another embodiment of the present invention.

FIG. 6A is an explanatory diagram showing an example of a track format of the present invention. FIG. 6B is an explanatory diagram showing an example of a servo area format of the present invention. FIG. 6C is an explanatory diagram showing an example of the data area format of the present invention. FIG. 6D is an explanatory view showing an example of the write ID area format of the present invention. FIG. 6E: An explanatory view showing an example of the write ID area format of the present invention.

FIG. 7 is a block diagram showing a configuration example of an electronic circuit of a disk device according to the present invention.

FIG. 8: Servo ID control process according to the present invention (first half)
It is a flowchart which shows an example.

FIG. 9: Servo ID control process according to the present invention (second half)
It is a flowchart which shows an example.

[Explanation of symbols]

101 1 sector 104 Servo area 106 dual head 107 light head 108 readhead 111 ID area for writing (W-ID) 112 ID area for reading (R-ID) 702 data processing unit 714 Mechanical part 713 Host computer.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masatoshi Nishina 2880, Kozu, Odawara-shi, Kanagawa Hitachi Ltd. Storage Systems Business Department (72) Inventor Katsumi Yamamoto 5-20-1, Kamimizumoto-cho, Kodaira-shi, Tokyo Hitachi Ltd. Semiconductor Division (56) References JP-A-6-180947 (JP, A) JP-A-8-31103 (JP, A) JP-A-7-254227 (JP, A) JP-A-5- 174498 (JP, A) JP-A-6-131856 (JP, A) JP-A-8-203253 (JP, A) JP-A-8-255465 (JP, A) JP-A-8-255467 (JP, A) JP-A-8-321142 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G11B 20/12 G11B 5/09

Claims (7)

(57) [Claims] 1. A method for formatting a disk-shaped data recording medium, wherein a plurality of tracks are arranged in a radial direction and the tracks are divided into a plurality of sectors each including a servo area and a data area. A data recording medium, characterized in that at least one write ID section in which information indicating a number is written is provided, and the write ID section is arranged before a servo area corresponding to the servo number indicated by the write ID section. Format method. 2. A rotating disk-shaped data recording medium
Read and write data with the rotation drive
Head and move it to a specified position
A head drive unit and the head on the data recording medium.
Read / write circuit for reading and writing data
And a command for controlling each part in response to instructions from the outside.
Disk device with disk device controller
Thus, the data recording medium has a plurality of tracks arranged in the radial direction.
Place the track in the servo area and the data area.
Format it so that it is divided into multiple sectors, each containing
The information indicating the servo number is written on the track.
If at least one writing ID section is provided,
In addition, the writing ID part is changed to the servo number indicated by it.
It is specially placed before the corresponding servo area.
Disk device to collect. 3. The write ID portion according to claim 2, wherein the write ID portion is of a servo area corresponding to the write ID portion.
A disk device that is arranged immediately before. 4. The write ID section according to claim 2 or 3, wherein error detection and correction are performed.
It is necessary to further provide an area for storing an ECC for storing
A disk device characterized by: 5. The user data according to claim 2 or 3, wherein user data is specified in a data area of each sector.
A reading ID section in which information for writing is written is provided.
A disk device characterized by being stored. 6. The head according to claim 2, wherein the head is a write head and a read head.
A dual head formed in a body, the center of the writing ID section in the track direction and the center of the server.
The deviation from the center of the track area in the track direction is
Half the tolerance between the head and the read head.
A disk device characterized by being arranged in such a manner. 7. The head according to claim 2, wherein the head is a write head and a read head.
A dual head formed in a body, the center of the writing ID section in the track direction and the center of the server.
Place it so that it coincides with the center of the track area in the track direction.
A disk device characterized by the following.