JPH08321142A - Method for judging correctness of servo sector address, disk-type storage, and its control device - Google Patents

Abstract

PURPOSE: To improve the reliability of a system by comparing an address read from a servo sector with a servo sector address which is predicted from the address and generating a required data sector address. CONSTITUTION: A CPU 11 calculates an address on a recording medium requested from a computer 15 and reports it to a control part 8. The control part 8 obtains a data sector address from the read signal and sends it to a control part 9. At the same time, a signal for following a head 6 is sent to a driver 5, thus enabling the head 6 to be moved to a target position and an amplifier 4 to amplify a signal read by the head 6 and output it to a device 3. The device 3 classifies data and sends it to the control part 9. The control part 9 judges whether the transmitted data are proper or not and sends the conforming data to a control part 12 and a control part 10. The control part 12 sends data whose error is corrected to a computer 15 by the control part 10 via a buffer 13 and a control part 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk type storage device and a disk control device which prevent deterioration of reliability and throughput in a high-efficiency format system by performing ID comparison multiple times.

[0002]

2. Description of the Related Art In recent years, as the functions and performances of personal computers and office computers have improved, the capacity of data storage devices, especially magnetic disk devices, has been increased.
There is a strong demand for higher performance. Based on this background,
Attention has been focused on a method of increasing the capacity by improving the format efficiency.

As an example of this approach, there is a method in which an ID area provided for identifying a sector is eliminated (this method is defined as "IDless format method"). The IDless format system is described in, for example, Japanese Patent Laid-Open No. 5-174478. The format configuration of the IDless format method will be described below with reference to FIG.

The disk format is for recording / recording data.
A servo sector (SSCT16) provided for controlling the position of the head on the recording medium for performing a reproducing operation, and a data sector (D) provided for storing user data.
SCT17).

An example of the servo sector 16 is shown in FIG.
This is shown as T Example 1.

Example 1 of SSCT is AGCG18, SVMK
19, IDXM20 / SCTM21, CYL22, PO
It is composed of S25 and ISG26. AGCG18 is
This is an area provided for adjusting the read gain of servo information. The servo mark (SVMK) 19 is an area provided to detect the head position of the servo sector. The index mark (IDXM) 20 / sector mark (SCTM) 21 is an area provided for identifying the beginning of a track or a sector. If the track is at the head, the index mark 20 is described. On the other hand, the sector mark 21 is described. CY
L22 is an area for storing a cylinder number (track number). The POS 25 is an area for storing detailed head positioning information between cylinders. The POS 25 is used for controlling the detailed positioning operation (settling) of the head and the following operation for always positioning the head on the target cylinder (following). The ISG 26 is an area provided to absorb the fluctuation in rotation of the disk.

On the other hand, when the data sector 17 adopts a format in which the recording density is constant over the inner and outer circumferences of the disk, the data sector 17 includes the servo sector (DSCTB) and does not include the servo sector (DSCTA). And have different configurations (see FIG. 2).

DSCTA is ISG26, PLO27,
It is composed of BS28, DATA29, ECC30, and PAD31. The ISG 26 is an area provided to absorb the rotational fluctuation of the disc. The PLO 27 is an area provided for clock synchronization with read data. BS28 is an area provided to indicate the timing of converting serial data into parallel data. The DATA 29 is an area for storing user data. The ECC 30 is an area for checking whether or not the read DATA 29 has an error and storing information necessary for correcting the error when the error is found as a result of the check.

[0009] DSCTB is basically a format in which SSCT16 is inserted in DSCTA. However, the PLO 27 and the BS 28 are arranged again after the SSCT 16. This is because the read process is interrupted once when passing through the SSCT 16 at the time of reading, and therefore it is necessary to perform clock synchronization and byte synchronization again in order to perform the read process again.

When such an IDless format system is used, the data sector 17 requested by the host computer is detected as follows. Here, it is assumed that the servo sector has the configuration of SSCT example 1 in FIG.

Since the data sector 17 does not have an ID portion storing the data sector address (DSA), the sector address (SSA) of the servo sector 16 is used to obtain the data sector address. That is, the address of the servo sector 16 including the index mark (IDXM) 20 is set to 0. Then, each time the sector mark 21 of the subsequent servo sector 16 is detected, the servo sector address is incremented by one. By sequentially counting the sector marks 21 in this manner, the sector address can be confirmed and the target servo sector 16 can be reached. After that, the data sector address (DSA) can be obtained using the address conversion table.

[0012]

However, in the IDless format method, in order to detect the address of the data sector 17, the index mark (IDXM) 20 and the sector mark (SCTM) stored in the servo sector 16 are detected. 21 and the servo mark (SVMK) 19 must be detected correctly. If any one of these is erroneously detected (or cannot be detected (missing)) during data access, the above-mentioned servo sector address (SSA) cannot be obtained correctly. Therefore, there is a possibility that user data may be destroyed or incorrect data may be transferred to the host computer.

A method proposed to solve such a problem is a method using a data format in which the SSA 23 is stored in the servo sector 16 (S in FIG. 2).
See SCT Example 2). In this method, the servo sector address can be confirmed by directly reading the SSA 23 in the servo sector 16 in which the head is actually located. However, even with this method, if an error occurs in the reading of the SSA 23, the same malfunction as described above will occur.

Further, the above-mentioned prior art also discloses a method of adding an error detection code (CRC) 24 to a servo address including the SSA 23 and checking whether or not the read CYL 22 and SSA 23 are correct. . However, if an error that cannot be detected by the CRC 24 occurs, a malfunction occurs.

An object of the present invention is to provide a highly reliable disk type storage device by preventing the above-mentioned erroneous detection of the servo sector address 23, destruction of user data due to non-detection (missing), and transfer of erroneous data. To do.

[0016]

The present invention has been made to achieve the above object, and a first aspect thereof is as follows.
A disk-type storage device for reading desired data from a disk-type storage medium, which comprises a data sector and a servo sector, and is formatted in a format in which an address of the servo sector (hereinafter referred to as "servo sector address") is written, Reading means for reading a servo sector address from a servo sector and reading data from the data sector; and a prediction means for predicting a servo sector address of a subsequent servo sector based on the servo sector address read by the reading means, The servo sector address read by the read means and the read means is 1
Compare with the servo sector address predicted by the predicting means based on the servo sector address read immediately before,
As a result of the comparison, when the two match, the determining unit determines that the reading of the servo sector address by the reading unit is correctly performed, and the determination unit determines that the reading of the servo sector address is correctly performed. If the means determines, the data sector address generating means for obtaining the address of the data sector subsequently arranged after the servo sector, and the reading means,
There is provided a disk type storage device characterized in that data is read from a data sector having an address obtained by the data sector address generation means.

In this case, in the case where the allocation of the servo sector address is performed by adding a predetermined value at a time, the prediction by the predicting means is based on the servo sector address read by the reading means immediately before. It may be performed by adding a predetermined value.

According to a second aspect of the present invention, a disk type storage medium is provided which has a data sector and a servo sector and is formatted in a format in which the address of the servo sector (hereinafter referred to as "servo sector address") is written in the servo sector. In a disk type storage device for reading out desired data, a reading means for reading a servo sector address from the servo sector and a data for reading the data sector, and a servo sector address for the servo sector address read by the reading means The above-mentioned calculation is performed on the basis of the calculation means for performing a predetermined calculation according to the allocation of the sector address, the servo sector address read by the read means, and the servo sector address read by the read means immediately before. If the result of the comparison is that the two have a predetermined relationship, it is determined that the reading of the servo sector address by the reading means has been correctly performed. If the determination means determines that the reading of the servo sector address has been correctly performed,
Data sector address generating means for obtaining an address of a data sector arranged after the servo sector, and the reading means reads data from a data sector having an address obtained by the data sector address generating means. A disk-type storage device is provided.

In this case, in the case where the allocation of the servo sector address is performed by adding a predetermined value at a time, the calculation by the calculating means is performed by the above-mentioned servo sector address read by the reading means immediately before. It may be one that adds a predetermined value.

According to a third aspect of the present invention, a disk type storage medium is provided which has a data sector and a servo sector and is formatted in a format in which an address of the servo sector (hereinafter, "servo sector address") is written in the servo sector. In a disk type storage device for reading out desired data, a reading means for reading out a servo sector address from the servo sector and a data for reading out the data sector, and a track composed of a plurality of data sectors and a plurality of servo sectors When the start mark is detected, the count value is reset, and each time the servo sector is detected, the count means increments the count value by a predetermined value; the servo sector address read by the read means; The count value of the count means is compared, and as a result of the comparison, if the two have a predetermined relationship, the determining means determines that the reading of the servo sector address has been correctly performed by the reading means; When the determination unit determines that the reading of the servo sector address has been performed correctly, the data sector address generation unit that obtains the address of the data sector subsequently arranged after the servo sector is provided, and the reading unit includes There is provided a disk type storage device characterized in that data is read from a data sector having an address obtained by the data sector address generation means.

In each of the above aspects, there is provided a second judging means for judging whether or not the address obtained by the data sector address generating means and the address of the data sector to be accessed at that time match. The reading means may read the data from the data sector located at the address when the two judgment results of the second judgment means match.

In each of the above aspects, a writing means for writing separately instructed data to the data sector is provided, and at the time of writing the data, the address obtained by the data sector address generating means is the access target at that time. A second judging means for judging whether or not the address of the data sector is coincident is provided, and when both of them are coincident with each other as a result of the judgment by the second judging means, the writing means causes the writing means to write the data sector concerned. Data may be written to the memory.

In each of the above aspects, there is provided a data sector information table in which information indicating the relationship between the servo sector address and the data sector address of the data sector arranged immediately after the servo sector of the servo sector address is written. The data sector address generation means may be provided with a stored memory means, and the data sector address generation means may obtain the data sector address by referring to the data sector information table.

According to a fourth aspect of the present invention, there is provided a disk type storage medium which comprises a data sector and a servo sector and is formatted in a format in which an address of the servo sector (hereinafter, "servo sector address") is written in the servo sector. In a controller of a disk type storage device used for reading and / or writing desired data by a head, a servo sector of a subsequent servo sector based on a servo sector address read by the head. Predicting means for predicting an address, the servo sector address read by the head, and the servo sector address previously predicted by the predicting means are compared, and if both match, the servo sector address is correct. Determination means for determining Control device for a disk-type storage device, characterized in that it comprises is provided.

According to a fifth aspect of the present invention, a disk type storage medium is provided which has a data sector and a servo sector and is formatted in a format in which the address of the servo sector (hereinafter referred to as "servo sector address") is written in the servo sector. In a controller for a disk-type storage device, which is used in a disk-type storage device for reading and / or writing desired data by a head, in a signal read by the head,
When a start mark of a track composed of a plurality of data sectors and a plurality of servo sectors is detected, the count value is reset, and each time the servo sector is detected, the count value is incremented by a predetermined value. The count means, the servo sector address read from the storage medium by the head, and the count value of the count means are compared, and if the comparison results in a predetermined relationship, the head is According to another aspect of the present invention, there is provided a control device for a disk type storage device, comprising: a determination unit that determines that the servo sector address read from the storage medium is correct.

According to a sixth aspect of the present invention, in a method for determining whether a servo sector address read from a servo sector of a recording medium is correct or incorrect, the servo sector address of the next servo sector is predicted based on the servo sector address read from the servo sector, The predicted servo sector address is compared with the servo sector address read from the next servo sector, and if the two match, it is determined that the read servo sector address is correct. There is provided a method of determining whether a servo sector address is correct or incorrect.

According to a seventh aspect of the present invention, in the method of determining the correctness of a servo sector address read from a servo sector of a recording medium, when a track start mark is detected, its count value is reset and a servo sector is detected. Each time, the count value is incremented by a predetermined value, the servo sector address read from the servo sector is compared with the above count value, and if the result of the comparison is that there is a predetermined relationship, then at this time Provided is a method of determining whether a read or writing servo sector address is correct, which is a correct or incorrect determination of the servo sector address.

[0028]

The first, second, fourth and sixth modes will be collectively described.

An address of the servo sector (hereinafter referred to as "servo sector address") is written in the servo sector of the storage medium. As such a data format, for example, the SSCT example 2 in FIG. 2 can be considered. However, the CRC 24 for the address may be omitted.

When accessing data, the reading means is
Read the servo sector address from the servo sector. The predicting unit predicts the servo sector address of the subsequent servo sector based on the servo sector address read by the reading unit. This means that when the addresses of the servo sectors are assigned such that the address of the servo sector including the index mark is set to 0 and the addresses of the following servo sectors are added one by one, this predicting means has a simple increment function. It can be realized with an up counter. In the second aspect, the calculation by the calculation means plays a role equivalent to this.

The judging means determines the servo sector address read by the reading means and the servo sector address predicted by the predicting means based on the servo sector address read by the reading means immediately before (or the calculation result by the calculating means). And, compare. As a result of the comparison, if the two match (or have a predetermined relationship), it is determined that the reading of the servo sector address by the reading unit has been correctly performed.

When the determining means determines that the servo sector address has been read correctly, the data sector address generating means determines the address (data sector address) of the data sector located after the servo sector from the servo sector address. Ask. This can be done, for example, by referring to the data sector information table which describes the relationship between the data sector address and the servo sector address.

The second judging means judges whether or not the address obtained by the data sector address generating means matches the address of the data sector which is the access target at that time. As a result of the determination, if the two match, the reading unit reads the data from the data sector or the writing unit writes the data.

The third, fifth and seventh modes will be collectively described.

The reading means reads the servo sector address from the servo sector.

In parallel with this, the counting means counts up the count value by a predetermined value each time the servo sector is detected, triggered by the detection of the servo sector that contained the track start mark. When the address of the servo sector is allocated such that the address of the servo sector including the index mark is 0 and the addresses of the following servo sectors are incremented by 1, the counting means increments by 1. It should be noted that, although the example of counting up is described here, the same is true for counting down.

The judging means compares the read servo sector address with the count value of the counting means. As a result of the comparison, if the two match, the determining unit determines that the reading of the servo sector address by the reading unit is correctly performed.

When it is determined that the servo sector address has been read correctly, the data sector address generating means obtains the address of the data sector located after the servo sector from the servo sector address. This can be done, for example, by referring to the data sector information table which describes the relationship between the servo sector address and the data sector address.

The second judging means judges whether the address obtained by the data sector address generating means matches the address of the data sector which is the access target at that time. If the result of this determination is that they match, the reading means reads the data from the data sector (or the writing means writes the data).

[0040]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to the drawings.

The present embodiment is premised on the data format in which the servo sector (SSCT) includes the servo sector address (SSA). Here, the following description will be made assuming that the data format of the servo sector is as shown in the SSCT example 2 of FIG. However, as a gray code, the head address (HD) 50
It also includes. On the contrary, the CRC 24 may be omitted in applying this embodiment. A part of the data format of this embodiment is shown in FIG.

FIG. 3 is a block diagram showing the system configuration of the disk device 1 which employs the data surface servo system. The disk device 1 includes a data processing device 2, a signal processing device 3,
Motor driver 5, R / W amplifier 4, R / W head 6,
It is composed of a data surface recording medium 7. The data processing device 2 further includes a CPU 11, a host interface control unit 14, a buffer control unit 12, a drive interface control unit 9, a servo control unit 8, an ECC control unit 10, and a data buffer 13.

The outline of the operation of each block will be described below by taking the reproduction operation as an example.

The CPU 11 calculates the address on the recording medium in which the data requested by the host computer 15 is stored. Then, this is notified to the servo control unit 8.

The servo controller 8 detects the CYL 22 and SSA 23 from the signal read from the recording medium 7 by the R / W amplifier 4, the signal processing device 3 and the like, and obtains the data sector address (DSA). Then, the data interface address (DSA) is notified to the drive interface control unit 9. Also, the POS 25 is detected, and the R / W is placed on the cylinder in which the requested sector exists.
A control signal for settling and following the head 6 is output to the motor driver 5.

The motor driver 5 controls the voice coil motor (VCM) and the spindle motor based on the control signal. As a result, the R / W head 6 is moved to the target position.

The R / W amplifier 4 amplifies the signal read by the R / W head 6 and outputs the amplified signal to the signal processing device 3.

The signal processing device 3 synchronizes the read data input from the R / W amplifier 4 with the PLO 27.
Take based on. Further, after discriminating the read data into a clock and NRZ data, these are transferred to the drive interface control unit 9. The above R / W
The amplifier 4, the R / W head 6, the signal processing device 3, etc. correspond to the "reading means" and the "writing means" in the claims.

The drive interface control unit 9 receives the data sector address (DS) notified from the servo control unit 8.
It is determined whether A) is the target address at that time. If it is the target address, BS28
Based on the above, the DATA 29 is converted from serial data into parallel data and transferred to the buffer control unit 12.
At the same time, the converted parallel data is transferred to the ECC control unit 10. The drive interface control unit 9 (especially ID / DAT described later
A comparator 62) is referred to in the claims as "second
It corresponds to "determination means".

The ECC control unit 10 uses the ECC 30 in the read data to correct the DATA 29 error. After that, the buffer control unit 12 determines that the data buffer 1
3, and via the host interface control unit 14, D
Transfer the ATA 29 to the host computer 15. In this case, if the ECC control unit 10 finds an error, the DATA 29 after the error correction is performed by the ECC control unit 10 is transferred.

This is the end of the outline of the reproduction operation. Note that the data recording operation is transferred in a route almost opposite to that of the reproducing operation, and is therefore omitted here.

Next, the servo control section 8 forming the center of the present invention.
The drive interface control unit 9 will be described in more detail.

FIG. 1 is a block diagram showing the configuration of the servo control unit 8.

The servo control unit 8 receives the read data pulse (RDP) 48 from the signal processing device 3. On the other hand, the data sector address (DSA) 57 and various control signals are output to the signal processing device 3 and the drive interface control unit 9.

Although not apparent in the drawing, the servo control sequencer 32 is connected to each part constituting the servo control part 8 and controls the output timing of the control signal generated by each part. Further, various flags, variables and the like necessary for the control are provided inside.

The servo clock generation circuit 33 generates a clock of a frequency necessary for the operation of the servo control unit 8 itself from an external clock of an oscillator or the like.

The RDP detection circuit 34 transfers the RDP 48 input from the signal processing device 3 to the servo clock generation circuit 3
In synchronization with the servo clock input from 3, the various circuits (35, 36, 37, 38) in the subsequent stage are notified.

The servo mark detection circuit 36 detects the SVMK 19 (see FIG. 2) from the RDP 48 synchronized with the servo clock. Similarly, from the RDP 48 synchronized with the servo clock, the index mark detection circuit 3
7 is the IDXM 20 and the sector mark detection circuit 38
Detects SCTM21 (see FIG. 2).

The Gray code converter 35 converts the Gray code (see FIG. 2, SSCT example 2) into a binary code. This gray code is the cylinder address (CYL)
22, a servo sector address (SSA) 23, and a head address (HD50) (see FIG. 5).

The current servo address latch 39 converts each of these addresses (CY) converted into a binary code.
(L, HD, SSA) is temporarily stored. Further, the servo address register 42 stores an address which is an access target at that time.

The comparator 1 (41) compares the addresses stored in the current servo address latch 39 and the servo address register 42 with each other to determine whether the read address is an address to be accessed. .

The current servo address latch 39
The cylinder address (CYL) 22 read from
In order to recognize the position of the R / W head 6 on the medium 7, C
It is also transferred to PU11.

On the other hand, the next servo sector address (S
The SA) prediction circuit 40 reads the servo sector address (SSA) 23 from the current servo address latch 39. Then, the read servo sector address (S
The servo sector address (SSA) 23 to be detected next is predicted from the SA) 23. The next servo sector address prediction circuit 40 corresponds to "prediction means" and "calculation means" in the claims.

The prediction is performed by incrementing the read servo sector address (SSA) 23 by one. The value obtained by the increment is the predicted value (NXTSSA) 71. However, this means that the allocation method of the servo sector address (SSA) 23 is such that the servo sector 16 including the index mark 20 is the reference (0) and the addresses of the following servo sectors 16 are added one by one. Is assumed. It goes without saying that the prediction method needs to be changed appropriately according to the allocation method of the servo sector address 23.

Next servo sector address (SSA)
An example of the prediction circuit 40 is shown in FIG. As I said,
The next servo sector address (SSA) prediction circuit 40 of this embodiment includes a flip-flop (FF) 66, an incrementer (INC) 67, a comparator 69, and a maximum SS.
It is composed of an A register (Max SSA Reg) 70 and a selector.

The flip-flop 66 of the next SSA prediction circuit 40 takes in the SSA read by asserting SADRINC73, and produces and outputs NXTSSA71. Further, the maximum SSA register 70 is preset with the maximum SSA (the highest number on the track, for example n). In the comparison by the comparator 69, the result of the SSA comparison in the nth servo sector,
If the maximum SSA and the read SSA match, the next SSA prediction circuit 40 uses SADRINC.
(Note: SSAINC in FIG. 5) SA instead of 73
Assert RST74. At the same time, the subsequent SSA, that is, "0" is set as a comparison target. In this case, the selector switches the output source of the NXTSSA 71 from the rear stage side of the incrementer 67 to the front stage (Q output of FF) side.

The comparator 2 (43) shown in FIG. 1 checks whether the read SSA 23 has an error by comparing the read SSA 23 with the NXTSSA 71 obtained by the prediction based on the SSA 23 read last time. . The comparator 2 (43) corresponds to the "determining means" in the claims.

The timing of this comparison will be described with reference to FIG. In order to latch the read SSA23, FIG.
The sequencer 32 shown in (1) outputs SSALTEN 77. Further, SSACMPEN 76 is output, and if the comparison shows that they match, the servo sector address (SSA) 23 read from the next sector is predicted in preparation for the next comparison. In other words, SSAINC73
To output this servo sector address (SSA) 23
Is incremented. However, the value of the servo sector address (SSA) 23 before the increment is the maximum SS
When the value matches the value of the A register 70, the next predicted servo sector 16 is the servo sector 16 including the index mark 20. So in this case,
SSARST7 to reset NXTSSA71
4 is output.

The SSA comparison operation described above will be described again with reference to FIG. 6 as a series of flow of each part related thereto. In the example of this figure, if the comparison result in the previous servo sector does not match, SS is used by using the flag for judging the comparison permission.
The comparison of A is not performed, and access to the subsequent data sector is prohibited.

After the processing is started, the servo control sequencer 32 sets the internal comparison flag to 0 in order to prevent the SSA from being compared in the first servo sector to be accessed.
(Step 602). Then, the current servo address latch 39 latches the SSA of the Mth servo sector according to the instruction from the servo control sequencer 32 (step 604). M is a servo control sequencer 32 for identifying the servo sector to be processed.
Is an internal variable. When this latch ends,
The servo control sequencer 32 determines whether the comparison flag is 1 (step 606). As a result of this judgment,
If the comparison flag is 1, the process proceeds to step 612. On the other hand, if it is not 1, the process proceeds to step 608. Since the comparison flag is set to 0 in step 602 described above, when step 606 is executed immediately after the start of the process of FIG. 6, the process always proceeds to step 608.

In step 608, the next SSA is
The prediction circuit 40 reads the SSA (RDSS) read in step 604 according to the instruction from the servo control sequencer 32.
NXTSSA is generated by adding 1 to A). At step 610, the servo control sequencer 32 sets 1 in the comparison permission flag. After that, the servo control sequencer 32 determines whether or not the access processing is ended by determining the instruction content from the CPU 11 (step 620). As a result, if it is not finished yet,
The servo control sequencer 32 increments M to move the servo sector to be accessed next (step 622). Then, the process returns to step 604 and the same processing is repeated.

By the way, when the comparison permission flag is 1 in step 606, the comparator 2 (43)
Compares RDSSA and NXTSSA to determine whether they match (step 612). As a result, if they match, the servo control sequencer 32 issues an instruction to permit access to the data sector after the servo sector, to the drive I / F control unit 9.
(Step 614). After this, the process moves to steps 608 and 610. If they do not match in step 612, the servo control sequencer 32
Outputs an instruction to prohibit access to the subsequent data sector to the drive I / F control unit 9 (step 61).
6). Then, the comparison permission flag is set to 0 so that the SSA comparison is not performed in the subsequent servo sector (step 618). After that, the process proceeds to step 620 and the same processing is repeated.

As described above, in this embodiment, if the servo mark 19 and the sector mark 21 are correctly detected from the previous servo sector 16, the servo sector address (SSA) from the target servo sector 16 at that time is detected. It is possible to determine whether or not 23 has been accurately detected.

As shown in FIG. 5, even if the servo mark 19 other than the above-mentioned target is not detected, the comparison result can be ignored, so that the throughput is not deteriorated due to the non-detection.

The SSA 23, which has been determined to have been correctly detected by the above comparison, detects the data sector information table 44 from the current servo address latch 39.
(See FIG. 1).

In the data sector information table 44, the address (DSA) 5 of the data sector 17 following the servo sector 16 corresponding to each SSA 23
7, the generation position of the sector pulse (SCTP) 58 indicating the start position of the next data sector 17, and the start position of the next servo sector 16 are stored. These pieces of information are information unique to each recording medium, are stored in the ROM (or recording medium), and are transferred to the servo control unit 8 as necessary. The table 44 may be provided in the data buffer 13 of FIG. In a device in which the recording medium is replaceable, the table information may be stored on the recording medium and read when the system is started up.

The SCTP generation circuit 45 generates a sector pulse (SCTP) 58 at the SCTP generation position shown in the data sector information table 44 and outputs it to the drive interface controller 9. Further, the index pulse (IDXP) 59 is generated and output to the drive interface control unit 9.

The data sector address generation circuit 46 outputs the DSA 57 shown in the data sector information table 44 to the drive interface control unit 9. The DSA 57 is incremented by the input of the SCTP 58. The data sector address generation circuit 46 corresponds to "data sector address generation means" in the claims.

The split length generation circuit 47 is provided for the data sector 1 arranged immediately before the subsequent servo sector 16.
7 position information (SP
TL) 56 to the drive interface control unit 9.

Next, details of the drive interface control section 9 will be described with reference to FIG.

The read / write sequencer 60 is IDXP
When 59 and SCTP 58 are input from the servo control unit 8, the operation is started. Then, the processing for the data sector 17 and the operation timing control of each circuit in the drive interface control unit 9 are performed.

The ID / DATA comparator 62 reads the D read from the data sector information table 44.
SA57 and D requested by the host computer 15
Compare with SA57.

As a result, if they match,
The data transfer unit 64 transfers data from the signal processing device 3 to the buffer control unit 12 when a data read request is made. When a data write request is issued, the data is transferred from the buffer controller 12 to the signal processing device 3.

The field counter 61 is instructed by the read / write sequencer 60 so that the data sector 17 (see FIG.
See each field).

Further, the processing interruption circuit 63, in order to temporarily interrupt the data processing on the servo sector 16 arranged in the middle of the data sector 17, the SPTL 56, END.
A split enable (SPTEN65) which is a processing interruption instruction signal is generated from S53 and is notified to each circuit.

In the embodiment described above, based on the servo mark 19 (or index mark 20) and sector mark 21 read from the servo sector 16 immediately before the servo sector to be accessed (hereinafter referred to as "target servo sector"). , The target servo sector 1
Predicting 6 servo sector addresses. Then, by comparing this predicted value with the servo sector address actually read from the target servo sector 16, the correctness of the read servo sector address is confirmed.
Therefore, highly reliable servo address detection can be realized, and destruction of user data and transfer of erroneous data can be prevented.

The prediction circuit 40 of the present embodiment is configured to add 1 to the read servo sector address in accordance with the allocation method of the servo sector address. However, the prediction circuit 40 may add numbers other than this. In this case, the prediction result does not match the servo sector address read out thereafter.
However, even in such a case, a certain relationship is maintained between the two. For example, the prediction circuit 40
However, if 2 is added to the read servo sector address, the prediction result should always be a value that is 1 larger than the servo sector address that is read thereafter. Therefore, by comparing the two, if such a relationship is established, it can be determined that the servo sector address has been read correctly.

Next, a second embodiment of the present invention will be described.

In the second embodiment, each time the presence of a servo sector is detected, the counter is incremented by a predetermined value and the servo sector address (SSA) contained in the servo sector is read out. Then, the correctness of the read servo sector address is confirmed by comparing the servo sector address read at that time with the count value up to that time.

The basic device configuration of the second embodiment is similar to that of the first embodiment (see FIG. 1). However, due to the adoption of the method described above, the next S in the first embodiment is
Instead of the SA prediction circuit 40 (FIG. 4), the servo control unit 8 is provided with an SSA counter circuit 78 corresponding to the counting means in the claims (see FIG. 8).

Here, as in the case of the first embodiment, the description will be made assuming the disk format of FIG.

The SSA counter circuit 78 counts up by a predetermined value (in this case, one by one) each time the servo sector 16 is detected, thereby indicating the servo sector address in which the R / W head 6 is currently passing. The servo sector address count (SSACNT) 85 is generated. That is, the SSA counter circuit 78 is a counter that sets the address of the servo sector 16 including the index mark 20 to 0 and counts up by one each time a subsequent servo sector 16 is detected. However, this presupposes that the servo sector address 23 is assigned with the servo sector 16 including the index mark 20 as the reference (0) and the addresses of the following servo sectors 16 are added one by one. If the address allocation method is different, the counting method is changed accordingly. Alternatively, the count value may be subjected to a predetermined calculation. For example, in the case where the address value is incremented by 2, the counter circuit 78 increments by 2 each time a servo sector is detected. Alternatively, the count value may be incremented by one each time the servo sector is detected, and thereafter the count value may be doubled.

In this embodiment, the SSA counter circuit 78 is provided with a flip-flop (FF) as shown in FIG.
79, an incrementer (INC) 80, a comparator 81, and a maximum SSA register (Max SSA Reg) 82. The SSA counter circuit 78 detects the index mark (IDXM) and resets it, and detects the sector mark (SCTM) and increments it.

In FIG. 8, the comparator 2 compares the SSA23 read at that time with the above-mentioned servo sector address count SSACNT85 to check whether the read SSA23 has an error. That is,
If they match, no error has occurred. On the contrary, if they do not match, an error (a read error of the SSA 23 or a detection error of the servo sector 16) has occurred.

An example of the timing of this comparison is shown in FIG. IDXMF84 in the figure is an instruction signal for resetting SSACNT85. This IDXMF84 is
S generated by the index mark detection circuit 37
It is input to the SA counter circuit 78. SCTMF83
Is an instruction signal for incrementing SSACNT85. The SCTMF 83 is generated by the sector mark detection circuit 38 and input to the SSA counter circuit 78.

In the second embodiment, all the servo marks 19, the index marks 20, and the sector marks 21 of all the servo sectors 16 from the servo sector 16 including the index mark 20 to the target servo sector 16 must be detected correctly. Is required. For example, as shown in FIG. 10, the target servo sector 16 is n,
Consider the case of n + 1. If the servo mark 19 or the sector mark 21 is not detected before the target servo sector 16 (SSA = 2 in the figure), SSACNT is detected.
The value of 85 is incorrect at that time. Then, the occurrence of the detection error becomes immediately apparent at that point by comparing the SSA23 and SSACNT85, and
The comparison determination in the target servo sector 16 also does not match. Therefore, in the second embodiment, the detection condition of the servo sector address is strict, and the servo sector address 23 can be detected with higher reliability.

[0097]

As described above, according to the present invention, I
When performing data processing for a disk format that adopts the D-less format method, erroneous detection of the servo sector address 23, destruction of user data due to non-detection (missing), and transfer of erroneous data are prevented, and the device and system The reliability can be improved.

[Brief description of drawings]

FIG. 1 is a servo control unit 8 according to a first embodiment of the present invention.
FIG.

FIG. 2 is a diagram showing an example of a disk format configuration adopting an IDless format system.

FIG. 3 is a system configuration diagram of the disk device according to the first embodiment of the present invention.

FIG. 4 is a diagram showing a configuration of a next servo sector address prediction circuit 40.

FIG. 5 is a diagram showing SSA comparison timing.

FIG. 6 is a flowchart showing SSA comparison processing.

FIG. 7 is a configuration diagram of a drive interface control unit 9.

FIG. 8 is a configuration diagram of a servo control unit 8 ′ according to a second embodiment of the present invention.

9 is a diagram showing a configuration of a servo sector address counter circuit 78. FIG.

FIG. 10 is a diagram showing SSA comparison timing.

[Explanation of symbols]

1 ... Disk device, 2 ... Data processing device, 8 ... Servo control unit, 9 ... Drive I / F control unit, 16 ... Servo sector, 17 ... Data sector, 19 ... Servo mark, 20 ...
Index mark, 21 ... Sector mark, 22 ... Cylinder address, 23 ... Servo sector address, 40 ... Next SSA prediction circuit, 44 ... Data sector information table, 57 ... Data sector address, 78
… SSA counter

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G11B 21/10 8425-5D G11B 21/10 E 27/10 27/10 A (72) Inventor Nakai Kousuke 1099 Ozenji, Aso-ku, Kawasaki-shi, Kanagawa Within Hitachi Systems Development Laboratory, Inc. (72) Inventor Masatoshi Nishina 2880 Kokuzu, Odawara, Kanagawa Stock Company Hitachi Storage Systems Division (72) Inventor Katsumi Yamamoto Tokyo 5-20-1 Kamimizuhonmachi, Kodaira-shi, Tokyo Incorporated company Hitachi Ltd. Semiconductor Division

Claims (12)

[Claims] 1. A disk-type storage medium, which comprises a data sector and a servo sector and is formatted in a format in which an address of the servo sector (hereinafter referred to as "servo sector address") is written in the servo sector,
In a disk-type storage device for reading desired data, a read means for reading a servo sector address from the servo sector and a data read from the data sector, and a subsequent read operation based on the servo sector address read by the read means Predicting means for predicting the servo sector address of the servo sector, servo sector address read by the reading means, and servo sector address predicted by the predicting means based on the servo sector address read by the reading means immediately before. As a result of the comparison, if the two match as a result of the comparison, the determining means determines that the reading of the servo sector address by the reading means is correctly performed, and the reading of the servo sector address is correctly performed. The above-mentioned judgment means If the determination is made, the data sector address generating means for obtaining the address of the data sector subsequently arranged after the servo sector is provided, and the reading means is provided from the data sector at the address obtained by the data sector address generating means. A disk type storage device characterized in that it reads data. 2. When the servo sector address is assigned by a method of incrementing by a predetermined value, the prediction by the predicting means is performed by the reading means by the predetermined servo sector address. The disk type storage device according to claim 1, wherein the operation is performed by adding values. 3. A disk-type storage medium that is formatted in a format that includes a data sector and a servo sector, in which the address of the servo sector (hereinafter referred to as "servo sector address") is written,
In a disk type storage device for reading out desired data, a reading means for reading a servo sector address from the servo sector and a data for reading the data sector, and a servo sector for the servo sector address read by the reading means The arithmetic means for performing a predetermined arithmetic operation according to the address allocation method, the servo sector address read by the read means, and the servo sector address read by the read means immediately before. Compares the result of performing the above predetermined operation, and if the result of the comparison is that the two have a predetermined relationship, it is determined that the reading of the servo sector address by the reading means has been correctly performed. Of the servo sector address And a data sector address generating unit for determining an address of a data sector arranged after the servo sector, when the determining unit determines that the reading is correctly performed. A disk type storage device characterized in that data is read from a data sector of an address obtained by. 4. When the allocation of servo sector addresses is performed by a method of incrementing by a predetermined value, the arithmetic operation by the arithmetic means is carried out by the servo sector address read out immediately before by the reading means. 4. The disk type storage device according to claim 3, wherein the values are added. 5. A disk-type storage medium, which is formatted in a format including a data sector and a servo sector, in which an address of the servo sector (hereinafter referred to as "servo sector address") is written,
In a disk-type storage device for reading desired data, a reading means for reading a servo sector address from the servo sector and a data from the data sector, and a start of a track composed of a plurality of data sectors and a plurality of servo sectors When the mark is detected, the count value is reset, and each time the servo sector is detected, the count value is incremented by a predetermined value, the servo sector address read by the read means, and the count The count value of the means is compared, and as a result of the comparison, if the two have a predetermined relationship, the determining means determines that the reading of the servo sector address by the reading means is correctly performed; Read sector address And a data sector address generating unit for determining an address of a data sector which is arranged after the servo sector, when the determining unit determines that the data sector has been correctly executed. A disk type storage device characterized in that data is read from a data sector of an address obtained by. 6. The read means comprises a second judging means for judging whether or not the address obtained by the data sector address generating means and the address of the data sector to be accessed at that time coincide with each other. Is a device for reading data from the data sector located at the address when the two are matched as a result of the judgment by the second judging means. 5. The disk type storage device according to item 5. 7. A writing means for writing separately instructed data to said data sector, wherein the address obtained by said data sector address generating means at the time of data writing is the address of the data sector to be accessed at that time. If the result of the determination by the second determining means is that both match, the writing means causes the writing means to write the data to the data sector. 7. The disk type storage device according to claim 1, 3, 5 or 6, wherein writing is performed. 8. A memory storing a data sector information table in which information indicating a relationship between the servo sector address and the data sector address of a data sector arranged immediately after the servo sector of the servo sector address is stored. 6. The data sector address generating means obtains the data sector address by referring to the data sector information table. , 6 or 7 disk type storage device. 9. A disk-type storage medium, which comprises a data sector and a servo sector and is formatted in a format in which an address of the servo sector (hereinafter referred to as "servo sector address") is written in the servo sector,
In a controller of a disk type storage device used for reading and / or writing desired data by a head, a servo sector address of a subsequent servo sector based on a servo sector address read by the head. Of the servo sector address read by the head and the servo sector address previously predicted by the predicting means, and when both match, the servo sector address is correct. A control device for a disk type storage device, comprising: a determination means for determining. 10. A head reads desired data from a disk-type storage medium which is formatted in a format including a data sector and a servo sector and in which the address of the servo sector (hereinafter referred to as "servo sector address") is written. And / or used in a disk storage device for writing,
In a control device of a disk type storage device, when a start mark of a track composed of a plurality of data sectors and a plurality of servo sectors is detected in the signal read by the head, the count value is reset, and the servo sector Every time when is detected, the counting means counts up the count value by a predetermined value, the servo sector address read from the storage medium by the head, and the count value of the counting means are compared. If the result of the comparison is that the two have a predetermined relationship, the servo sector address read from the storage medium by the head is determined to be correct. Control device. 11. A method for determining the correctness of a servo sector address read from a servo sector of a recording medium, wherein the servo sector address of the next servo sector is predicted based on the servo sector address read from the servo sector, and the predicted servo sector address , The servo sector address read from the next servo sector is compared, and if the two match, the read servo sector address is determined to be correct. Correctness determination method. 12. A method for determining the correctness of a servo sector address read from a servo sector of a recording medium, wherein when a track start mark is detected, the count value is reset, and each time the servo sector is detected, the count value is set to a predetermined value. Each time, the servo sector address read from the servo sector is compared with the above count value, and if the result of the comparison is that there is a predetermined relationship, the servo sector address read at this time is A method for determining whether a servo sector address is correct or incorrect, which is characterized by determining that it is correct.