JPH10275425A - Disk device and method for high-speed host transfer of relocated data due to defect in the device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To rapidly transfer the required data to a host device when a read access for an area containing a defect sector is requested. SOLUTION: The data rearranged on an alternative area on a disk 10 are read out by an HDC 1 under control of a CPU 3 when a disk device is initialization operated to be held beforehand in a defect hold area after being copied. Then, when a read command for a disk area containing the defect sector imparted from the host device is executed, the rearranged data held in the defect hold area in the buffer 2 are read in by the HDC 1 under the control of the CPU 3 to be transferred to the host device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk drive in which a defective sector is relocated to an alternative area when a defective sector exists on a recording surface of a disk, and more particularly to a read operation for an area including the defective sector. The present invention relates to a disk device suitable for executing an access request and a high-speed host transfer method of relocation data due to a defect in the device.

[0002]

2. Description of the Related Art Generally, in a disk device in which data is recorded / reproduced on a recording single plate as a recording medium, that is, a disk (disk medium) by a head, for example, in a magnetic disk device, a recording surface of the disk (magnetic disk) is formed. When a defect (defect) exists in the disk, the defect area is relocated to an alternate area on the disk in sectors (data sectors) without notifying a host device (host system) such as a personal computer of the fact. Processing (alternative processing) is performed. By this relocation processing, the host device does not need to be aware of the defective area on the disk,
Continuous access to the area including the defective sector (write / write
Read out).

[0003] Here, in the case where the magnetic disk device receives an access command, for example, a read command for an area including a sector (defective sector) determined to be a defective area and rearranged in the replacement area, from the host apparatus, The data access procedure of the magnetic disk device will be described with reference to the diagram showing the head (magnetic head) moving path in FIG. 13 and the flowchart in FIG.

When the magnetic disk device receives a read command from the host device (step S41), the magnetic disk device performs a read operation to an area (designated read range) 110 on the disk (magnetic disk) 100 shown in FIG. Is started in the following procedure (step S42).

[0005] First, the magnetic disk device moves the magnetic head to the track including the defective sector 111 specified by the read command from the host device (path b1). Next, the magnetic disk device waits for rotation of the disk 100 until the head sector position of the read designated range 110 designated by the host device comes (path b2). Next, the magnetic disk device performs access (read operation) until immediately before the defective sector 110 (path b3).

As described above, when the read operation is started (step S42) and the read operation is performed up to immediately before the defective sector 110, the magnetic disk device temporarily suspends the read operation at the position b4 immediately before the defect 110. (Step S43).

In the next step S44, the magnetic disk drive moves the magnetic head to a track having an alternative area 112 including the target rearranged sector 113 (path b).
5) In the next step S45, the sector 113
Wait for the rotation of the disk 100 until the disk comes (path b).
6).

In the next step S 46, the magnetic disk drive performs a read operation on the relocated sector 113 (which is a substitute sector for the defective sector 111) (path b 7), and performs a read operation at the end position b 8 of the sector 113. Stop temporarily.

In the next step S47, the magnetic disk drive moves the magnetic head to the original track having the defective sector 111 (path b9). In the next step S48, the magnetic head moves to the sector position immediately after the defective sector 111. The disk 100 waits for rotation (path b10).

In the next step S49, the magnetic disk drive performs a read operation from the sector immediately after the defective sector 111 to the last sector in the designated read range 110 (path b11).

[0011]

As described above, in the prior art, in order to separately access the substitute area, operations such as interruption of access and movement of the head are required, and the access to the access area designated by the host device is required. There is a problem that execution time is significantly increased for access when a defective sector is not included. In addition, this causes a decrease in performance of the magnetic disk device and a variation in performance between airframes (magnetic disk devices).

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object that when read access to an area including a defective sector is requested from a host device, the requested data can be transferred to the host device at high speed. An object of the present invention is to provide a disk device and a high-speed host transfer method of relocation data due to a defect in the device.

[0013]

According to the disk apparatus of the present invention, when a defective sector is present on the recording surface of a disk, the defective sector is relocated to an alternative area on the disk, whereby the defective sector is deleted. A high-speed memory in which a defect holding area for holding data relocated to the replacement area is secured in a disk device capable of accessing the relocated data according to the relocation information at the time of access; A relocation data copy processing means for previously copying data relocated to an alternative area from the disk to the defect holding area in sector units, and a read command for a disk area including a defective sector provided from a host device Read the relocation data of the defective sector from the defect holding area Characterized in that a relocation data reading and transfer means for transferring to the host device.

As described above, the data relocated to the substitute area is copied and held in advance in a high-speed memory, and the substitute area is designated in response to a read command from the host apparatus for a disk area including a defective sector. By reading the relocated data held in the memory and transferring the read data to the host device without accessing, the access operation to the alternative area after the data read immediately before the defective sector, that is, the movement of the head, the head reaches the target area Therefore, it is possible to omit the same access operation from the alternate area to the area immediately after the defective sector from the disk rotation wait, and thus it is possible to shorten the execution time of the read command from the host to the area including the defective sector.

The present invention is also characterized in that the rearrangement data copy processing means in the disk device is activated when the disk device is initialized. In this way, when the disk device is initialized, for example, when the power is turned on, or when a hardware reset signal is input from the host device, the relocation data is copied (read) to the defect holding area on the memory, thereby performing this operation. Can cause the relocation data to be held in the defect holding area without deteriorating performance due to collision with a command from the host device.

Further, according to the present invention, in the copy processing of the relocation data by the relocation data copy processing means, when the total amount of data relocated to the replacement area is larger than the capacity of the defect holding area. The corresponding relocation data is copied in the descending order of the physical distance between each defective sector and its relocation destination until the defect holding area becomes full.

As described above, even in the case where a large number of defective sectors are present, the relocation data of the defective sector having a small amount of movement of the head to the replacement area is preferentially transferred to the defect holding area, thereby deteriorating the performance. Can be minimized.

Further, according to the present invention, access number management means for managing the number of accesses to each of the defective sectors after the initialization operation of the disk device is provided, and when the defect holding area is full, the data is relocated to the defect holding area. If there is a defective sector in which data has not been copied and a defective sector whose access frequency is larger than that of the defective sector whose relocation data has been copied in the defect holding area, the defective sector whose access frequency is low is relocated. Instead of the data, the relocation data copy processing means,
It is also characterized in that the relocation data of the defective sector having a large number of accesses is copied to the defect holding area.

As described above, when the defect holding area is full, the defect holding area always holds the relocation data of the defective sector which is frequently accessed, thereby minimizing the deterioration in performance. Can be minimized.

The present invention is also characterized in that each time a new defective sector is relocated to the replacement area, the relocation data copy processing means copies the relocation data to the defect holding area. And

By immediately reading the relocation data into the defect holding area immediately after the relocation to the replacement area, the operation of accessing the replacement area and reading the relocation data is omitted, and the latest data is always read. Can be reflected in the defect holding area. However, when the defect holding area is full, this processing cannot be applied.

Therefore, according to the present invention, when a new defective sector is relocated to the replacement area, and the defect holding area is full, the relocation data copied to the defect holding area is If there is relocation data that has never been accessed, instead of that data, if there is no relocation data that has never been accessed, instead of the most recently accessed relocation data, The relocation data copy processing means copies relocation data of a new defective sector to the defect holding area.

As described above, immediately after the relocation to the alternative area,
Even if the relocation data is read into the defect holding area, if the defect holding area is full, the relocation data which is least likely to be used among the relocation data held in the defect holding area is read. By replacing it with the newly relocated data,
Performance degradation can be minimized.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a magnetic disk drive will be described below with reference to the drawings.
FIG. 1 is a block diagram showing a configuration of a magnetic disk drive according to one embodiment of the present invention.

In FIG. 1, reference numeral 10 denotes a disk (magnetic disk) as a medium on which data is recorded;
0 (data recording) and disk 10
This is a head (magnetic head) used for reading data from the memory (data reproduction). The head 7 is mounted on the disk 1
It is assumed that each of them is provided corresponding to each recording surface of No. 0. In this embodiment, the disk 10 is a single disk, but a plurality of disks 10 may be provided in a stacked manner.

A large number of concentric tracks are formed on both surfaces of the disk 10. Each track is used for positioning control and the like (a cylinder code indicating a cylinder number, and a positional error in the cylinder indicated by the cylinder code is represented by a waveform. A plurality of servo areas in which servo data is recorded (including burst data for indicating the amplitude of the data) are arranged at equal intervals. These servo areas are radially arranged on the disk 10 from the center over each track. A data area (user area) is provided between the servo areas, and a plurality of data sectors are set in the data area.

In a predetermined area (system area) of the recording surface of the disk 10, defective sector relocation information (hereinafter referred to as a defect map and a defective sector) indicating a defective sector on the recording surface and its replacement destination (relocation destination) sector and the like. Is stored.

The disk 10 has a spindle motor (SP
M) 11 to rotate at high speed. The head 7 is attached to a head moving mechanism called a carriage mechanism 9, and moves in the radial direction of the disk 10 by the movement of the carriage mechanism 9. The carriage mechanism 9 is driven by a voice coil motor (VCM) 13.

The SPM 11 is connected to an SPM driver 12 for supplying a control current to the SPM 11 to drive the SPM 11, and a VCM 13 for supplying a control current to the VCM 13 to drive the VCM 13.
It is connected to the driver 14. The value (control amount) of the control current is determined by calculation processing of the CPU (microprocessor) 3.

The head 7 is connected to a head amplifier circuit 8 mounted on, for example, a flexible printed circuit (FPC). The head amplifier circuit 8 is responsible for switching the head 7, inputting / outputting read / write signals to / from the head 7, etc., and a head amplifier (preamplifier) for amplifying an analog output read by the head 7; W circuit 6
A write driver (both not shown) for outputting a write signal (write current) to the head 7 in accordance with the write data sent from the printer.

The R / W circuit (read / write circuit) 6
A decode function (read) for inputting an analog output (read signal of the head 7) read from the disk 10 by the head 7 and amplified by the head amplifier circuit 8 (internal head amplifier) and performing signal processing necessary for data reproduction operation Channel), an encoding function (write channel) for performing signal processing required for recording data on the disk 10, and a signal processing function for extracting burst data from servo data required for servo processing such as head positioning control. And

The servo processing circuit 15 receives the data reproduced by the R / W circuit 6 and executes signal processing necessary for servo processing. In other words, the servo processing circuit 15 is a well-known timing signal that is valid (true) only during the servo area period from the data reproduced by the R / W circuit 6, and is recorded in the servo area such as a timing generation function such as a servo gate. It has a decoding function to extract and decode the cylinder code in the servo data.

The GA (gate array) 5 includes an R / W circuit 6
In addition to transferring information between the servo processing circuit 15 and the HDC 1 and the CPU 3, monitoring the timing of the servo gate generated by the servo processing circuit 15, a data sector arranged in a data area subsequent to the corresponding servo area The HDC 1 has a function of notifying the HDC 1 of the position information.

The CPU 3 is, for example, a one-chip microprocessor. The CPU 3 controls each unit in the magnetic disk device according to a control program stored in the ROM 4. That is, the CPU 3 controls the servo processing circuit 15
The head 7 is moved to a target cylinder (track) position by controlling the drive of the VCM driver 14 in accordance with the cylinder code in the servo data extracted by the above and the burst data in the servo data extracted by the R / W circuit 6. Control such as seek / positioning control and transfer control of read / write data by controlling the HDC 1 is performed.

The CPU 3 includes a ROM (Read Only Memory) 4 for storing a control program (firmware) for controlling the entire magnetic disk drive, and an HDC.
(Disk controller) 1 is connected.

The HDC 1 has a host interface function for controlling communication of commands and data with the host device in accordance with the host interface standard, a buffer management control function for managing the buffer 2, an R / W circuit 6, a head amplifier, It has a disk control function for controlling the timing of read and write operations on the disk 10 performed via the circuit 8.

The buffer 2 is a high-speed memory, for example, a buffer memory having a RAM configuration. As shown in FIG. 2, each area of the buffer area 21, the defect map area 22, and the defect holding area 23 is secured in the buffer 2.

The buffer area 21 provides a cache area used for temporarily storing data read from the disk 10 and write data to the disk 10 transferred from the host device.

The defect map area 22 is an area for storing a defect map indicating a defective sector on the recording surface and a replacement destination (relocation destination) sector thereof, and the like.
For each recording surface (head) of the disk 10, cylinder information indicating a cylinder in which a defective sector exists, a cylinder information area 221 for registering pointer information to a storage location of information of the defective sector on the cylinder, and cylinder information Region 22
1 includes a sector information area 222 for registering information on defective sectors on cylinders indicated by the cylinder information in 1.

The sector information area 222 contains, for each defective sector, information 222a of the defective sector (alternative source sector).
In addition to the information 222b of the replacement destination sector (relocated sector) of the defective sector and the defect type 222c of the defective sector, (the replacement destination sector of the defective sector)
The information on the number of times 222d of access to and the copy flag 222e is registered. The copy flag 222e indicates whether or not the data of the relocation destination has been copied to the defect holding area 23 (the relocation data copy area 232 therein) of the buffer 2 to be described later.

The defect map stored in the defect map area 22 is used when the magnetic disk drive is initialized (for example, when the power of the drive is turned on or when a hardware reset signal is input from the host device). It is read from the area. However, the number of accesses 222d in the sector information for each defective sector
The copy flag 222e is unique to the defect map area 22, and is added to sector information for each defective sector in the defect map read from the system area of the disk 10.

The defect map in the defect map area 22 is used to determine whether a defective sector is included in the requested access range when a disk access is requested from the host device, and to determine whether a defective sector is included in the requested access range. Is
It is used for detecting the position of the defective sector and determining whether or not the data of the corresponding relocated sector has been copied to the defect holding area 23 (the relocated data copy area 232 therein).

When a new defective sector is detected and relocation processing to a replacement sector is performed, information on the defective sector is registered in the defect map, that is, the defect map is updated in the buffer 2. Is performed for both the defect map area 22 and the system area of the disk 10.

Next, the defect holding area 23 includes a table area 231 and a relocation data copy area 232. The relocation data copy area 232 is used by dividing the size of one sector (for example, 512 bytes) into units, and the data of the relocation destination of the defective sector on the disk 10 in the one sector division area, that is, The data of the relocation sector (alternative destination sector) is copied. Table area 23
Reference numeral 1 denotes a copy destination position information indicating which position (divided region) in the relocation data copy area 232 is copied (stored) in which relocation sector, and indicates a relocation sector. It is used to register table information including relocation sector information for each relocation sector. Here, the relocation sector information includes a sector number of the relocation sector and information indicating a cylinder and a head where the relocation sector exists.

Next, the operation of the magnetic disk drive having the configuration shown in FIG. 1 will be described. (A) Relocated Sector Data Copy Process First, a relocated sector data copy process for copying data of a relocated sector stored in an alternative area on the disk 10 to a defect holding area 23 secured on the buffer 2 is described as an example. Next, a description will be given with reference to FIG.

Now, the sector # 3 on the cylinder where the normal recording area on the disk 10 is located is a defective sector, and the defective sector # 3 is one of the alternative sectors ( (Relocated sector).

In this state, when the power of the apparatus is turned on or a hardware reset signal is input from the host apparatus, the CPU 3 starts an initializing operation for initializing each unit in the magnetic disk apparatus. I do. In this initialization operation, the CPU 3 reads out the defect map stored in the system area on the disk 10 and stores the defect map in the defect map area 22 of the buffer 2 by controlling the HDC 1. At this time, the sector information for each defective sector in the defect map stored in the defect map area 22 includes an access frequency 222d indicating the access frequency 0d.
And a copy flag 222e indicating non-copy.

When the power is turned on or when a hardware reset signal is input, that is, during the initialization operation of the magnetic disk drive, the CPU 3 transfers the data of the relocated sector stored in the substitute area on the disk 10 to the The HDC 1 controls the HDC 1 to perform a process of copying data to the relocation data copy area 232 secured in the defect holding area 23 of the buffer 2 in sector units. At the same time, the CPU 3 performs a process of registering, in the table area 231 for each relocated sector, table information including the information of the copied relocated sector and the location information of the copy destination. Further, the CPU 3 copies the copy flag 222e added to the sector information on the defective sector corresponding to the copied relocated sector among the sector information for each defective sector in the defect map stored in the defect map area 22. Set to a status indicating that

Here, the total amount of data of all relocation sectors indicated by the defect map is the relocation data copy area 232.
If the capacity is larger than the capacity, the optimum copy target relocation sector is selected by a method described later.

In the present embodiment, the above-described copy processing is also performed immediately after the detection of a new defective sector and the relocation to the replacement sector is performed. That is, CP
U3 copies the data of the relocated replacement sector, that is, the relocated sector to a free area in the relocated data copy area 232, and stores a table including information on the copied relocated sector and location information of the copy destination. The process of registering information in the table area 231 is executed by controlling the HDC1.

In this manner, the area for one sector in the relocation data copy area 232 secured in the defect holding area 23 of the buffer area 21 is
It is assumed that the data of the relocated sector of the sector # 3 on 0 is copied, and table information indicating the relocated sector and the copy destination is stored in the table area 231.

(B) Operation at Read Command Reception Next, the operation when a read command is issued from the host device to the area including the relocated defective sector is described as (b1) Skip reading sector setting to HDC. , And (b2) the read operation will be described with reference to the flowchart of FIG.

(B1) Setting of skipped read sectors to HDC First, the operation of setting skipped read sectors to HDC1, which is performed when a read command for an area including a relocated defective sector is received, will be described.

Now, a read command for the area including the relocated defective sector # 3 as shown in FIG. 3 is issued from the host device to the magnetic disk device of FIG.
Assume that the read command is received by the HDC 1 in the magnetic disk device (step S1).

When the CPU 3 receives the read command received by the HDC 1, based on the defect map stored in the defect map area 22 of the buffer 2, the CPU 3 sets the replacement area in the read target area specified by the read command. It is determined whether or not the relocated defective sector is included, and if so, whether or not the data (relocated sector data) of the replacement destination sector of the defective sector has been copied to the defect holding area 23. Judge. Here, the defective sector # is included in the read target area.
No. 3 is included, and the data of the relocated sector of the defective sector # 3 is recognized as being copied to the defect holding area 23 (the relocated data copy area 232 therein). At the same time, the CPU 3
Sector # in the defect map stored in the
Number of accesses 2 added to sector information related to 3
22d is incremented by one.

The CPU 3 determines that the read target area includes the defective sector # 3, and the defective sector # 3
Is determined to have been copied to the defect holding area 23, the HDC 1
As shown in FIG. 5, the defective sector # 3 is set as a skip-read target sector, and the data transfer to the host device is temporarily stopped at the skip-read stage. Further, the CPU 3 refers to the table area 231 in the defect holding area 23, and refers to the relocation data copy area 23 in which the data of the relocation sector # 3 has been copied.
2 is specified in advance.

(B2) Read Operation Next, the read operation following the setting operation of (b1) will be described with reference to FIGS. 5 to 9 in addition to the flowchart of FIG. FIG. 9 shows the same head movement path as FIG. 13 referred to in the description of the conventional technique.

First, when the CPU 3 performs the setting operation (b1) as a pre-process before the execution of the read command from the host device, the CPU 3 starts the read operation specified by the read command in the following procedure (step S2). Here, the read operation includes a disk read operation for reading data in a designated area on the disk 10 and a host transfer operation for transferring data read from the disk 10 to a host device.

First, the CPU 3 moves the head 7 from the current position to the disk 1 shown in FIG.
Move to the track where the read designated range (read target area) 90 on 0 exists (path a1). It is assumed that the read designated range 90 includes a defective sector 91 which is a defective sector # 3 to which skip reading has been set earlier.

When the head 7 can be positioned on the track where the designated read range 90 exists, the HDC 1 waits for the rotation of the disk 10 until the head sector position of the designated read range 90 comes (path a2).

Next, the HDC 1 has a defective sector 91 (# 3).
Until immediately before, data is read from the disk 10 in sector units (path a3), and the data stored in the buffer area 21 is stored in the buffer area 21 of the buffer 2 while the read data is stored in the buffer area 21 of the buffer 2 in sector units. Transfer to This is shown in FIG. Here, an example is shown in which the disk is read from two sectors # 1 and # 2, and the read data is transferred to the host device.

When the HDC 1 transfers the data of the sector (# 2) immediately before the defective sector 91 (# 3) to the host device, only the host transfer is interrupted as shown in FIG. I do.

As described above, the read operation is started (step S2), and when the data is transferred to the host device in sector units until immediately before the defective sector 91 (# 3), the host transfer is temporarily suspended (step S3). . In the present embodiment, the disk reading by the HDC 1
1 operates independently of the host transfer. Therefore, during the interruption of the host transfer, the defective sector 91 (# 3)
Is skipped (path a4), and the buffer area 21 is read.
Reads the data of the sector (# 4) immediately after the defective sector 91 (# 3).

When the data of the sector (# 2) immediately before the defective sector 91 (# 3) is transferred to the host device, the CPU 3 sets the transfer source to the host device to the relocation data copy of the defect holding area 23. The relocation data of the defective sector 91 (# 3) copied to the area 232 is switched to the head position, that is, the previously specified position, and the relocation data for one sector from the relocation data copy area 232 is switched. After the host transfer of (relocated sector data), the HDC 1 is set so as to interrupt the host transfer.

As a result, the HDC 1 transfers the relocation data of the defective sector 91 (# 3) copied to the relocation data copy area 232 to the host device as shown in FIG. 7 (step S4). The host transfer is interrupted (path a5). In parallel with this, in HDC1, FIG.
As shown in (1), the data of the sector (# 4...) Immediately after the defective sector 91 (# 3) is read into the buffer area 21 (path a6).

Next, when the HDC 1 transfers the relocated sector data to the host device, the HDC 1 interrupts the host transfer according to the setting from the CPU 3. Then, the CPU 3 sets the HDC1 so that the transfer source to the host device is the position of the sector (# 4) immediately after the defective sector 91 (# 3), and restarts the host transfer by the HDC1.

As described above, in the HDC 1, the host transfer and the disk read operate independently, so that the buffer area 21 stores the defective sector 91 () during the interruption of the host transfer from the buffer area 21. The data of the sector (# 4 ...) immediately after # 3) has been read. Therefore, in response to the host transfer restart instruction from the CPU 3, the defective sector 91 (#
From the sector (# 4...) Immediately after 3), the transfer to the host device is resumed as shown in FIG. 8 (step S5) (path a7).

Thereafter, the HDC 1 sets the read designation range 9
The disk is read up to the last sector of 0 and host transfer of the read sector data is performed (path a8). Then, when the data of the last sector is transferred to the host device, a series of read operations is completed.

According to the above-described read operation (b2), as is apparent from a comparison between FIG. 9 and FIG.
The moving distance of the head has been greatly reduced. As is well known, a large proportion of the time required for the disk access operation is occupied by the operation of moving the head to the target track (seek operation) and the disk which waits until the magnetic head comes to the position where the target sector exists. This is the rotation waiting time.

In the prior art, as shown in FIG. 13, when the relocated sector data is accessed, two more seek operations and two more rotation wait operations occur as compared with the case where there is no defective sector. You needed a lot of extra time to do so.

On the other hand, in the present embodiment, the data relocated to the replacement area is copied and held in the defect holding area 23 in the buffer area 21 in advance, and the disk area including the defective sector from the host apparatus is targeted. By reading the relocation data held in the defect holding area 23 and transferring the read data to the host device without accessing the alternative area in response to the read command, the access to the alternative area after the data read immediately before the defective sector is performed. Since the operations, that is, the movement of the head, the disk rotation waiting until the head reaches the target area, and the similar access operation from the replacement area to immediately after the defective sector can be omitted, as shown in FIG. Can be reduced to almost zero.

This is roughly based on the following three reasons. (1) Disk access (disk read) and host transfer are performed independently and in parallel.

(2) The time required for the host transfer position change operation and the transfer suspend / restart operation is sufficiently shorter than the disk access operation. (3) Even if a long time is required for the operation (2), if the host transfer is faster than the disk access, the host transfer that is once delayed catches up with the disk access, and the delay time becomes longer. Canceled.

As described above, in this embodiment, the execution time of the read access operation to the disk area including the defective sector can be greatly reduced. (C) Selection of Copy Target Relocation Sector Next, the process of selecting the copy target relocation sector will be described with reference to the flowchart of FIG.

In the present embodiment, when the power is turned on or when an initialization operation such as input of a hardware reset signal is performed, the data of the relocated sector stored in the alternate area on the disk 10 is rewritten in the buffer area 21. The operation of copying to the arrangement data copy area 232 is automatically performed.
At this time, if the total amount of data of all the relocation sectors on the disk 10 indicated by the defect map is larger than the capacity of the relocation data copy area 232, it is necessary to select the relocation sector to be copied.

For this reason, at the time of initialization of the apparatus, the CPU 3 checks whether or not the total amount of data of all relocation sectors indicated by the defect map is larger than the capacity of the relocation data copy area 232 (step S11). Is the descending order of the number of tracks from a defective sector (with a certain track) to a relocated sector (with a certain track), that is, the physical distance (the amount of head movement when seeking to the relocated sector).
The corresponding relocated sector is selected as a copy target in the descending order (step S12), and the process of copying the data of the selected relocated sector to the relocated data copy area 232 (step S13) is performed in the relocated data. Repeat until the copy area 232 is full (step S1
4). This selection method is applied to a case where data of a relocated sector having a long moving distance (seek distance) of a magnetic head from a defective sector to a relocated sector (alternate destination sector) is copied to the relocated data copy area 232. This is because the effect of shortening the execution time of the read command for the disk area including the corresponding defective sector is great.

If there is a relocated sector in which data has not been copied to the relocated data copy area 232, that is, an uncopied relocated sector (defective sector corresponding to), the access frequency is high. Copying the data of the relocated sector to the relocated data copy area 232 has a greater effect of reducing the execution time of the read operation from the disk area including the defective sector using the relocated data copy area 232.

Therefore, in this embodiment, replacement (replacement) of relocation data is performed as shown in the flowchart of FIG. First, when an access is made to the defective sector (including the area), the CPU 3 checks whether or not the data of the relocated sector of the defective sector to be accessed is uncopied (step S21). In some cases, the CPU 3 determines from the defect map stored in the defect map area 22
The access count (222d) of the defective sector to be accessed is read (step S22).

Next, the CPU 3 determines, from the defect map, one of the defective sectors corresponding to the copied relocated sector (indicated by the copy flag 222e) having a smaller number of accesses than the number of accesses read in step S22. It is checked whether or not there is (Step S2)
3). If there is a defective sector with a small number of accesses, the relocation data of the defective sector to be accessed is copied to the relocation data copy area 232 instead of the copied relocation data of the defective sector (step S2).
4). That is, the relocation sectors to be copied to the relocation data copy area 232 are dynamically replaced based on the access count of each relocation sector. In this operation, the relocation data of the defective sector to be accessed is stored in the buffer area 21 of the buffer 2.
When the data is read from the relocation sector, it is efficient because rereading from the relocated sector is unnecessary.

In addition, when a new defective sector is detected and relocation to the relocated sector is performed, there is a high possibility that (the relocated sector of) the defective sector will be accessed again soon. Considering that a sector that has not been accessed for a long time is unlikely to be accessed again soon, it is also possible to replace the relocation data as shown in the flowchart of FIG.

First, when a new defective sector is detected and the relocation process to the relocation sector occurs, the CPU 3 includes at least one of the relocation data copied in the relocation data copy area 232. Check whether there is any relocation data that has not been accessed (step S
31).

If there is copied relocation data that has never been accessed, the CPU 3 selects the relocation data as a replacement (removal) target (step S32).

On the other hand, if there is no copied relocation data that has never been accessed,
Selects the most recently accessed relocation data among the relocation data copied to the relocation data copy area 232 as a replacement (eviction) target (step S33). For this purpose, the relocation data copy area 2
For each piece of relocation data in 32, information indicating the access order may be provided in, for example, each piece of table information in the table area 231.

Next, the CPU 3 determines in step S32 or S
Instead of the relocation data selected in step 33, the relocation data immediately after the relocation is copied to the relocation data copy area 232 (step S24).

In addition, not only a newly detected defective sector but also a newly accessed sector is highly likely to be accessed again soon. It is also applicable when an access to the URL occurs.

In the above description, a defect holding area is secured in a buffer for temporarily storing data read from the disk and data to be written to the disk, and the relocation data of a replacement sector for a defective sector on the disk is secured. Has been described, but a high-speed memory independent of the buffer may be used as the defect holding area.

In the embodiments described above, the magnetic disk device has been described. However, according to the present invention, when a defective sector exists on the recording surface of a disk, the defective sector is relocated to an alternative area on the disk. In a disk device that can access data relocated according to the relocation information when accessing a defective sector,
The present invention is also applicable to disk devices other than magnetic disk devices, such as magneto-optical disk devices.

[0088]

As described above in detail, according to the present invention, data relocated to an alternative area is copied and held in a high-speed memory in advance, and a disk area including a defective sector from a host device is targeted. In this case, the relocation data stored in the memory is read and transferred to the host device without accessing the alternative area in response to the read command, so that the access operation to the alternative area after the data read immediately before the defective sector is performed. Thus, the access operation from the replacement area to immediately after the defective sector can be omitted, and the execution time of the read command can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a magnetic disk drive according to an embodiment of the present invention.

FIG. 2 is a view for explaining each area allocated to a buffer 2 in FIG. 1;

FIG. 3 is an exemplary view for explaining relocation sector data copy processing in the embodiment.

FIG. 4 is an exemplary flowchart for explaining the operation at the time of receiving a read command from the host device for a disk area including a defective sector according to the embodiment;

FIG. 5 is an exemplary view for explaining an operation of setting a skip-read sector to the HDC 1 in the embodiment.

FIG. 6 is an exemplary view for explaining a disk read operation and a host transfer operation up to immediately before a defective sector in the embodiment.

FIG. 7 is a view for explaining a host transfer operation of relocation data after transferring data of a sector immediately before a defective sector to a host device and a disk read operation of data of the sector immediately after the defective sector in the embodiment. FIG.

FIG. 8 is an exemplary view for explaining a host transfer operation of data of a sector immediately after a defective sector in the embodiment.

FIG. 9 is an exemplary view showing a head moving path at the time of a read operation for a disk area including a defective sector in the embodiment.

FIG. 10 is an exemplary flowchart for explaining the process of selecting a copy target relocation sector according to the embodiment;

FIG. 11 is an exemplary flowchart for explaining replacement processing of relocation data according to the embodiment;

FIG. 12 is an exemplary flowchart for explaining another replacement process of the relocation data in the embodiment.

FIG. 13 is a diagram showing a head moving path at the time of a read operation on a disk area including a defective sector in a conventional magnetic disk device.

FIG. 14 is a flowchart for explaining an operation when a read command is received from a host device for a disk area including a defective sector in a conventional magnetic disk device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... HDC (disk controller, relocation data reading / transfer means) 2 ... buffer (high-speed memory) 3 ... CPU (relocation data copy processing means) 7 ... head 10 ... disk 21 ... buffer area 22 ... defect map area (access) 23: Defect holding area 222d: Access frequency 222e: Copy flag 231: Table area 232: Relocation data copy area

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI G11B 20/18 512 G11B 20/18 512D 552 552A 572 572B 572F

Claims (8)

[Claims] 1. When a defective sector is present on a recording surface of a disk, the defective sector is relocated to an alternative area on the disk, so that when the defective sector is accessed, the relocation is performed according to the relocation information. A high-speed memory in which a defect holding area for holding data relocated to the replacement area is secured; and a data storage apparatus for storing the data relocated to the replacement area in advance. A relocation data copy processing means for copying sectors from the disk to the defect holding area in sector units; and a relocation of the defective sectors when a read command provided for a disk area including a defective sector provided from a host device is executed. Relocation data for reading data from the defect holding area and transferring the data to the host device. A disk device comprising: a data read / transfer unit. 2. The disk device according to claim 1, wherein the relocation data copy processing means is started at least during an initialization operation of the disk device. 3. When the total amount of data relocated to the replacement area is larger than the capacity of the defect holding area, the relocation data copy processing means may determine whether the defective sector and the relocation destination are physically located. 3. The disk device according to claim 2, wherein the corresponding relocation data is copied in order of increasing target distance until the defect holding area becomes full. 4. An apparatus according to claim 1, further comprising access number management means for managing the number of times of access to each of said defective sectors, wherein said relocation data copy processing means is provided for a defective sector whose relocation data has not been copied to said defect holding area. If there is a defective sector whose access frequency managed by the access frequency management means is larger than that of the defective sector whose relocation data is copied in the defect holding area, the defective sector whose access frequency is smaller is selected. 4. The disk device according to claim 3, wherein, instead of the relocation data, the relocation data of the defective sector whose access frequency is large is copied to the defect holding area. 5. The relocation data copy processing means, each time a new defective sector is relocated to the replacement area, copies the relocation data to the defect holding area. The disk device as described above. 6. The relocation data copy processing means, when the new defective sector is relocated to the replacement area, if there is no free space in the defect holding area,
If there is any relocation data that has never been accessed among the relocation data copied to the defect holding area, instead of that data, if there is no relocation data that has never been accessed, 6. The disk drive according to claim 5, wherein the relocation data of the new defective sector is copied to the defect holding area instead of the relocation data accessed most recently. 7. When a defective sector is present on a recording surface of a disk, the defective sector is relocated to an alternative area on the disk, so that when the defective sector is accessed, the relocation is performed according to the relocation information. A high-speed host transfer method of relocated data due to a defect in a disk device capable of accessing the relocated data, wherein the data relocated to the replacement area is transferred from the disk to a defect holding area secured in a high-speed memory. When a read command for a disk area including a defective sector given from the host device is executed, the relocation data of the defective sector is read out from the defect holding area and transferred to the host device when the read command is executed. High-speed host transfer of relocation data due to defects characterized by Method. 8. The method according to claim 7, wherein the operation of copying the data relocated to the replacement area to the defect holding area in sector units is performed at an initialization operation of the disk drive. High-speed host transfer method for configuration data.