JP2001184800A - Disk device and reassigning method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem that a spare area is densely arranged to suppress increase of response delay time after a reassignment processing, however, on the other hand, use efficiency of a disk is lowered when the spare area is densely arranged, with respect to a disk device to perform the reassignment processing when an unrecoverable defect is generated on a recording surface of the disk. SOLUTION: The recording surface of plural disks are divided into plural cylinder groups consisting of plural cylinders respectively and spare tracks are assigned to each of the divided cylinder groups in by one. When the spare track are assigned in this way, head seek quantity to be required for accessing the spare area is reduced by accessing the spare area on other recording surface from a defective sector by using switching of heads and the spare area is accessed in shorter time. Thus, increase of the response delay time to the access to an alternative sector is reduced, consequently, capacity of the spare track is reduced and the use efficiency of the disk is enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk drive and a reassignment method, and more particularly to a disk drive and a reassignment method for performing an unrecoverable defective sector.

[0002]

2. Description of the Related Art Generally, a recording surface of a disk has a sector which is a minimum area for storing data.
Then, a track is formed in which all the sectors existing at the same distance from the center of the disk rotation are grouped. Further, a cylinder is formed as a set of tracks on a plurality of recording surfaces and located at the same distance from the center of rotation.

[0003] A disk device is provided with a head for recording or reproducing data on each of the recording surfaces of a plurality of disks. When data is recorded or reproduced by accessing a certain sector, the head that is currently recording or reproducing data is switched to a head corresponding to the recording surface on which the desired sector is located (hereinafter, this operation is referred to as “operation”). Is referred to as head switching), and at the same time, the switched head is moved so as to be located on a track where a desired sector exists (hereinafter, this operation is referred to as head seek). Thereafter, when the desired sector reaches the position of the head by rotation of the disk, data recording or reproduction is performed.

[0004] Since the disk device records or reproduces data by the above-described operation, if the sector to be accessed is on a recording surface different from the currently accessed sector, the head is switched. Is required, and if the current sector is located on a different cylinder from the currently accessed sector, a head seek is required. Switching heads takes several hundreds of microseconds, and head seeking takes ten or more ms or more in the case of, for example, moving from the outermost track to the innermost track of the disk. Therefore, the switching of the head and the execution of the head seek increase the response delay time of the disk device. Therefore, normally, continuous data recording is performed so that data can be recorded or reproduced without requiring head switching or head seek.
The data is recorded in circumferentially consecutive sectors on the same track.

[0005] On the other hand, in the above disk device, when recording or reproducing data, an unrecoverable error may occur in a specific sector. When such an error occurs, a method of recording or reproducing data without reformatting is a reassignment process. The reassign process is a process of allocating, as a substitute sector, a sector in a spare area called a spare area, which is previously allocated to a recording surface of a disk, for a defective sector in which an unrecoverable error has occurred.

[0006] After the reassignment process, when a process for recording or reproducing data to or from the defective sector occurs, each time an access is made to the substitute sector assigned by the reassignment process, and the data recording is performed. Or playback is performed. That is, in the case where the replacement sector is assigned to a different recording surface or a different cylinder from the defective sector by the reassignment process, after the reassignment process, each time the process for the defective sector occurs, the head is switched or the head seek is performed. Will be executed. As described above, the switching of the head and the execution of the head seek lead to an increase in the response delay time of the disk device. Therefore, in the reassignment processing, the replacement sectors are arranged so that the increase in the response delay time is minimized. It is desirable. In particular, in the case where data recording or reproduction processing is performed again on the sector following the defective sector after accessing the replacement sector, the sector following the defective sector reaches the head again regardless of how short the access time is. Increase in response delay time corresponding to one rotation of the disk until
It is desirable to suppress the increase in the response delay time to a time corresponding to one rotation of the disk.

Conventionally, there have been the following three methods as measures against the above demands. The first method is disclosed in
This is a method disclosed in Japanese Patent Application Publication No. 45190/1992, in which one or a plurality of recording surfaces of a plurality of disk recording surfaces are all allocated as a spare area for allocating a substitute sector during reassignment processing. According to the first method, since the spare area can be accessed only by switching the head from an arbitrary defective sector, the spare area can be accessed only by the time required for switching the head from the defective sector. It is possible to arrange sectors. Therefore, it is possible to suppress an increase in the response delay time after the reassignment process.

The second and third methods divide the recording surface of the disk into a plurality of zones in the radial direction, and provide a spare track for each zone. In general, the recording surface of a disk is divided into a plurality of zones in the radial direction, and data is recorded or reproduced at a higher clock frequency in the outer zone in the radial direction, thereby improving the linear recording density of the disk recording surface. The overall recording capacity can be improved. Such recording methods are based on zones,
This is called bit recording (hereinafter referred to as ZBR). The second and third methods mainly use such Z
This is a method of arranging a spare area and a substitute sector in a disk employing BR.

A second method is a method disclosed in Japanese Patent Laid-Open No. 6-96525, and FIG. 8 is a conceptual diagram of a cross section of a disk for showing an arrangement position of a spare area according to the conventional method. is there. As shown in the figure, the innermost track of each of a plurality of divided zones (only the outermost zone 1 of the plurality of zones is shown in detail in the figure) is assigned as a spare track. Is the way. According to the second method, since the head seek to the substitute sector is a movement from the outermost circumference to the innermost circumference in one zone at the maximum, the head seek time can be reduced as compared with the case where the zone is not divided. . Also,
Generally, in each zone, the inner track has a smaller area per sector, and errors are more likely to occur. Therefore, by providing a spare track at the innermost periphery of the zone where a defective sector is likely to occur, an increase in the overall response delay time is further suppressed.

A third method is disclosed in Japanese Patent Application Laid-Open No. H10-134516.
In each of the plurality of zones, a spare area is located at a position where it can be accessed and returned from an arbitrary sector in the zone in a time equivalent to one rotation of the disk. In addition, at the time of reassignment, the disk is located at a predetermined angle from the defective sector in the spare area. This is a method of locating the replacement sector at a position separated by more than the angle at which the rotation is performed. According to the third method, the time from when the alternative sector is accessed to when the alternative sector is returned can be suppressed to a time equivalent to one rotation of the disk or less.

[0011]

However, in the first method, since at least one entire disk recording surface is used as a spare area, the ratio of the capacity of the spare area to the total capacity of the disk device becomes large. However, there is a problem that the use efficiency of the disk is reduced.
Further, in the second method, when a defective sector occurs at the outermost periphery of the zone, a considerable head seek time is required. Therefore, the increase in the response delay time of the disk device can be reduced by the time of one rotation of the disk. In order to suppress this, it was necessary to reduce the width of the zone and make the interval between the spare tracks dense. Then, also in this case, there is a problem that the ratio of the spare area is increased and the use efficiency of the disk is reduced. Further, in the third method, the increase in the response delay time of the disk device is suppressed to the time of one rotation of the disk. In this case, too, the spare sector is mainly determined based on the access time to the alternative sector by head seek. And the assignment of the alternative area is determined, as a result, the second
As in the above method, there is a problem that the ratio of the spare area is increased and the use efficiency of the disk is reduced.

[0012] Therefore, an object of the present invention is to reduce the proportion of a spare area for reassignment processing in the entire disk device, and to suppress an increase in response delay time due to access to a substitute sector after reassignment. To provide a disk device.

[0013]

Means for Solving the Problems and Effects of the Invention The first invention is a disk device for performing reassignment processing on unrecoverable defective sectors, and includes one or more disk-shaped recording media, and Is a disk-shaped recording means having a plurality of recording surfaces, a disk drive means for rotating a disk-shaped recording medium, and provided for each of the plurality of recording surfaces to record or reproduce data on the corresponding recording surface. Area arrangement for arranging a spare area for arranging a substitute sector for a defective sector in reassignment processing at different positions on a plurality of recording surfaces. Means.

As described above, according to the first aspect, the spare area for arranging the replacement sector is arranged at a different position on each of the plurality of recording surfaces. By using the switching, it becomes possible in a shorter time. Therefore, it is possible to suppress an increase in response delay time due to access to the substitute sector after the reassignment process. In addition, the capacity of the spare area can be reduced accordingly, and the use efficiency of the disk can be improved.

In a second aspect based on the first aspect, the spare area arranging means arranges the spare areas on a plurality of recording surfaces so as to be shifted from each other in a radial direction of the disk-shaped recording medium. Features.

As described above, according to the second aspect of the present invention, the spare areas are shifted in the radial direction for each recording surface, so that the spare areas can be easily located at different positions on the plurality of recording surfaces. Can be arranged.

In a third aspect based on the second aspect, data is stored in sector units on each of the plurality of recording surfaces, and the plurality of recording surfaces located at the same distance from the center of rotation on each recording surface. The sectors collectively form one track. On each recording surface, a plurality of tracks existing at the same distance from the center of rotation collectively form one cylinder. The spare area arranging means arranges a spare track having the entire area of the track as a spare area on a track on a different cylinder for each recording surface.

As described above, according to the third aspect, the spare track for allocating the replacement sector is arranged in a different cylinder for each recording surface, so that the spare areas are different from each other on the plurality of recording surfaces. It can be easily arranged in a position.

In a fourth aspect based on the third aspect, the plurality of cylinders defined on each recording surface are classified into a plurality of cylinder groups, and a spare track is arranged for each recording surface. Are characterized by belonging to mutually different cylinder groups.

As described above, according to the fourth aspect of the present invention, one spare track for arranging a substitute sector is arranged for each cylinder group. Can be easily arranged. Furthermore, the density of the spare area can be easily changed by arbitrarily setting the size of the cylinder group individually.

In a fifth aspect based on the first aspect, the spare area arranging means arranges the spare area on each of the plurality of recording surfaces so as to be shifted from each other in the rotation direction of the disk-shaped recording medium. Features.

As described above, according to the fifth aspect of the present invention, the spare areas are arranged so as to be shifted in the rotation direction for each recording surface, so that the spare areas can be easily arranged at mutually different positions on the plurality of recording surfaces. can do.

In a sixth aspect based on the fifth aspect, data is stored in sector units on each of the plurality of recording surfaces, and the spare area arranging means sets the spare area to each recording area from the center of rotation. It is characterized in that it is arranged in sectors of different angle ranges for each surface.

As described above, according to the sixth aspect, since the spare area is arranged in the sector having a different angle range for each recording surface, the spare area can be easily arranged at different positions on the plurality of recording surfaces. can do.

In a seventh aspect based on the sixth aspect, the angle range in which the spare area is arranged for each recording surface is separated by a predetermined angle or more for each recording surface.

As described above, according to the seventh aspect, since the spare area is arranged in a sector having a different angle range for each recording surface, the spare area can be easily arranged at different positions on the plurality of recording surfaces. can do.

In an eighth aspect based on the seventh aspect, the predetermined angle is an angle at which the disk-shaped recording medium rotates during a time required for switching the head.

As described above, according to the eighth aspect of the present invention, the spare area is arranged for each recording surface in a sector in an angular range separated by an angle equal to or more than the rotation angle of the disk during the time required for head switching. It is possible to access a spare area on another recording surface from a spare area on one recording surface in a short time by using head switching. Therefore, when performing reassignment processing on a plurality of continuous defective sectors, even when all of the replacement sectors cannot be arranged only by the spare area on a certain track, it is possible to access in a short time by using the head switching. It is possible to arrange the remaining alternative sectors in the spare area of the recording surface of the second. Therefore, it is possible to suppress an increase in response delay time due to access to the substitute sector after the reassignment process. In addition, the capacity of the spare area can be reduced accordingly, and the use efficiency of the disk can be improved.

According to a ninth aspect, in any one of the first to eighth aspects, a spare area which can be accessed from a defective sector in the shortest time and is available is replaced with a spare sector for the defective sector. Further, there is provided an alternative sector arranging means for arranging.

As described above, according to the ninth aspect, the replacement sector for the defective sector is located in an available spare area accessible in the shortest time from the defective sector, so that the replacement sector is allocated to the replacement sector after the reassignment processing. It is possible to suppress an increase in the response delay time due to the access of the user.

According to a tenth aspect of the present invention, in a disk device including one or more disk-shaped recording media and having disk-shaped recording means having a plurality of recording surfaces as a whole, a spare area for an unrecoverable defective sector is replaced with a spare area. And arranging spare areas at different positions on a plurality of recording surfaces, and allocating a replacement sector to the spare area.

As described above, according to the tenth aspect, the spare area for arranging the replacement sector is arranged at a different position on each of the plurality of recording surfaces. By using the switching, it becomes possible in a shorter time. Therefore, it is possible to suppress an increase in response delay time due to access to the substitute sector after the reassignment process. In addition, the capacity of the spare area can be reduced accordingly, and the use efficiency of the disk can be improved.

According to an eleventh aspect, in the tenth aspect,
The step of arranging the spare area is characterized in that the spare area is arranged to be shifted from each other in the radial direction of the disk-shaped recording medium with respect to each of the plurality of recording surfaces.

As described above, according to the eleventh aspect, by arranging the spare area in the radial direction for each recording surface, the spare area can be easily located at different positions on the plurality of recording surfaces. Can be arranged.

According to a twelfth aspect, in the eleventh aspect,
On each of the plurality of recording surfaces, data is stored in units of sectors. On each recording surface, a plurality of sectors existing at the same distance from the center of rotation collectively form one track. In each recording surface, a plurality of tracks existing at the same distance from the center of rotation are collectively formed to form one cylinder, and the step of arranging the spare area includes the steps of: It is characterized in that spare tracks as areas are arranged on tracks on different cylinders for each recording surface.

As described above, according to the twelfth aspect, the spare track for arranging the replacement sector is arranged in a different cylinder for each recording surface, so that the spare areas are different from each other on the plurality of recording surfaces. It can be easily arranged in a position.

According to a thirteenth aspect, in the twelfth aspect,
The method further includes the step of classifying a plurality of cylinders defined on each recording surface into a plurality of cylinder groups, wherein the cylinders on which spare tracks are arranged for each recording surface belong to mutually different cylinder groups. Features.

As described above, according to the thirteenth aspect, one spare track for arranging the replacement sector is arranged for each cylinder group, so that the spare area is located at a different position on each of the plurality of recording surfaces. Can be easily arranged. Furthermore, the density of the spare area can be easily changed by arbitrarily setting the size of the cylinder group individually.

According to a fourteenth aspect, in the tenth aspect,
The step of arranging the spare area is characterized in that the spare area is arranged so as to be shifted from each other in the rotation direction of the disk-shaped recording medium with respect to each of the plurality of recording surfaces.

As described above, according to the fourteenth aspect, since the spare areas are arranged so as to be shifted in the rotation direction for each recording surface, the spare areas can be easily arranged at mutually different positions on the plurality of recording surfaces. can do.

According to a fifteenth aspect, in the fourteenth aspect,
Data is stored in sector units on each of the plurality of recording surfaces, and the means for arranging the spare area includes arranging the spare area in a sector having a different angular range from the center of rotation for each recording surface. Features.

As described above, according to the fifteenth aspect, since the spare area is arranged in the sector having a different angle range for each recording surface, the spare area can be easily arranged at different positions on the plurality of recording surfaces. can do.

According to a sixteenth aspect, in the fifteenth aspect,
The angle range in which the spare area is arranged for each recording surface is separated by a predetermined angle or more for each recording surface.

As described above, according to the sixteenth aspect, since the spare area is arranged in the sector having a different angle range for each recording surface, the spare area can be easily arranged at different positions on the plurality of recording surfaces. can do.

According to a seventeenth aspect, in the sixteenth aspect,
In the disk device, the predetermined angle is an angle at which the disk-shaped recording medium rotates during a time required for switching the head.

As described above, according to the seventeenth aspect, the spare area is arranged for each recording surface in sectors within an angular range separated by an angle equal to or more than the rotation angle of the disk during the time required for head switching. It is possible to access a spare area on another recording surface from a spare area on one recording surface in a short time by using head switching. Therefore, when performing reassignment processing on a plurality of continuous defective sectors, even when all of the replacement sectors cannot be arranged only by the spare area on a certain track, it is possible to access in a short time by using the head switching. It is possible to arrange the remaining alternative sectors in the spare area of the recording surface of the second. Therefore, it is possible to suppress an increase in response delay time due to access to the substitute sector after the reassignment process. In addition, the capacity of the spare area can be reduced accordingly, and the use efficiency of the disk can be improved.

In an eighteenth aspect based on any one of the tenth to seventeenth aspects, the step of allocating a replacement sector is performed in such a manner that the spare area can be accessed from a defective sector in the shortest time and can be used. In this case, a substitute sector for a defective sector is arranged.

As described above, according to the eighteenth aspect, the replacement sector for the defective sector is located in the available spare area accessible in the shortest time from the defective sector. It is possible to suppress an increase in the response delay time due to the access of the user.

[0049]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 is a block diagram showing a configuration of a disk drive according to a first embodiment of the present invention. In FIG. 1, this disk device
Discs 110a and 110b and disc rotating shaft 130
, Motor 140, heads 150a, 150b, 15
0c, 150d, an actuator arm 160, a voice coil motor (hereinafter, referred to as VCM) 170, and a hard disk controller (hereinafter, referred to as HDC) 18
0. The disk 110a has a recording surface 120
a, 120b, and the disk 110b
0c and 120d.

The operation of the first embodiment will be described below. The present disk device is a disk device that employs the above-described ZBR method, and has recording surfaces 120a,
Ob, 120c, and 120d are each divided into a plurality of zones. The HDC 180 allocates a spare track as a spare area for each of the divided zones. At this time, spare tracks are allocated so that a plurality of spare tracks do not exist on the same cylinder. Furthermore, H
The DC 180 controls the motor 140 and the VCM 170 to record or reproduce data on a desired sector. Further, when the desired sector is a defective sector, a substitute sector for the defective sector is arranged in the spare area, that is, reassignment processing is performed.
The motor 140 rotates the disks 110 a and 110 b via the disk rotation shaft 130 under the control of the HDC 180. Heads 150a, 150b, 150c,
150d is supported by the actuator arm 160 so as to face the recording surfaces 120a, 120b, 120c and 120d, respectively, and records or reproduces data with respect to a desired sector. VCM 170 is H
Under the control of the DC 180, the heads 150a, 150
b, 150c and 150d are connected to the actuator arm 16
0 is moved in the radial direction of the disk.

Next, a method for arranging a spare area by the HDC 180 will be described in more detail with reference to FIG. FIG. 2 is a conceptual diagram of a cross section of the disk for showing the arrangement position of the spare area in the first embodiment. As shown, the recording surfaces 120a, 120b, 120c,
Reference numeral 120d denotes a plurality of zones (hereinafter, referred to as zone 1, zone 2,..., Zone N from the outside of the disk, respectively).
Respectively. FIG. 2 shows the arrangement of the spare area in the outermost zone 1 among the plurality of divided zones. Zone 1 is composed of 24 tracks (hereinafter, also referred to as tracks 1, 2,..., 24). On the four recording surfaces, four tracks existing at equal distances from the center are gathered to form one cylinder, respectively, and 24 cylinders corresponding to the 24 tracks (hereinafter similarly referred to as 24 cylinders). , Cylinders 1, 2,..., 24) are formed. The 24 cylinders are classified into four cylinder groups each consisting of 9, 7, 5, and 3 cylinders (hereinafter, also referred to as cylinder groups 1, 2, 3, and 4).

In each cylinder group, a spare track is allocated to one of the four tracks constituting the central cylinder. FIG.
In FIG. 7, the hatched portion surrounded by a thick line indicates a spare track assigned to each cylinder group. As shown in FIG.
A spare track is assigned to the track 5 on the track 20a. Similarly, in the cylinder group 2, the recording surface 1
The track 13 on the recording surface 120d in the track 13 on the track 13 on the recording surface 120c in the cylinder group 3 and the track 13 on the recording surface 120d in the cylinder group 3.
Are each assigned a spare track.

Hereinafter, a description will be given of the fact that a spare sector can be allocated from a defective sector to a substitute sector in a shorter time by comparing with the prior art shown in FIG. In the conventional example shown in FIG. 8, as in the present embodiment, the zone 1 has 24 tracks (hereinafter, as in the present embodiment, from the outside of the disk).
Tracks 1, 2,..., 24).

For example, according to the conventional arrangement, for example, in FIG. 8, when a defective sector occurs in the track 5 on the recording surface 120d, a substitute sector for the defective sector is set in the track 24 on the same recording surface. It is arranged on the arranged spare track, that is, reassign processing is performed.
Therefore, for access from a defective sector to an alternative sector,
The time required for the head seek for 19 (= 24-5) tracks is required. On the other hand, according to the present embodiment,
In FIG. 2, when a defective sector occurs on the track 5 on the recording surface 120d, a substitute sector for the defective sector is arranged in a spare track arranged on the track 5 on the recording surface 120a. Therefore, the access from the defective sector to the replacement sector requires time for switching the head. Normally, the time required for switching the head is equivalent to the time required for the head seek for one or two tracks. Therefore, in the access to the alternative sector, the head seek for 17 to 18 tracks compared to the conventional arrangement is required. Is reduced.

In the above description, the case where the spare track can be accessed only from the defective sector only by the head seek has been described. However, in other cases, the access time to the substitute sector is similarly reduced. For example, in the conventional arrangement method shown in FIG.
When a defective sector occurs in the track 10 on the track c, an alternative sector is arranged on the spare track arranged on the track 24 on the same recording surface, and 14 tracks are used to access the alternative sector from the defective sector. It takes time equivalent to a minute head seek. On the other hand, according to the arranging method according to the present embodiment shown in FIG. 2, when a defective sector occurs in the track 10 on the recording surface 120c, a replacement is made in the spare track arranged on the track 13 on the recording surface 120b. Sectors are arranged, and a time corresponding to a head seek for three tracks and a time required for head switching are required for access from the defective sector to the replacement sector, that is, a total of 4 to 5 times.
It takes time corresponding to the head seek for a track. In other words, according to the arrangement method of the present embodiment shown in FIG. 2, the time corresponding to the head seek for 9 to 10 tracks is shortened in accessing the alternative sector as compared with the conventional arrangement method shown in FIG. Will be.

As described above, according to the conventional spare area arranging method shown in FIG. 8, since the spare tracks are arranged at the same position on each recording surface, it is possible to access from any defective sector in the shortest time. Spare trucks that can be
It exists on the same recording surface as the defective sector, and is accessed by head seek from the defective sector. On the other hand, according to the spare area arrangement method of the present embodiment, since the spare tracks are arranged at different positions on each recording surface, for example, the arrangement density of the spare tracks for each recording surface is the same as in the conventional case. Even if there is, by switching the head, it is more preferable to access a spare track existing on a different recording surface from the defective sector than to access a spare track existing on the same recording surface as the defective sector. In some cases, access can be made in a short time. Therefore, it is possible to access the spare area from an arbitrary defective sector in the same time as in the related art or in a shorter time than in the related art, thereby suppressing an increase in the response delay time of the disk device.

The disk device of the present embodiment has a ZB
Although the recording surface is divided into a plurality of zones because the disk device adopts the R system, this is a case where the disk device does not employ the ZBR system, that is, the entire recording surface is a single zone. However, a spare track may be arranged for each of the plurality of cylinder groups in the same manner.
In general, the number of cylinders constituting each zone is often about several hundreds. In this embodiment, the number of cylinders included in the zone 1 is set to 24 for the purpose of explanation. It is not something to be done. Further, the position and the number of spare tracks arranged for each cylinder group can be set according to the disk device to be used. Further, the number of spare tracks arranged in each zone may be different.

The size of each divided cylinder group is not limited to that shown in FIG. 2 and may be arbitrarily divided. However, for example, as in the present embodiment, ZBR
On the recording surface of a disc adopting the system, in each zone, the inner track has a higher linear recording density,
Since the recording density is close to the limit, the probability of occurrence of defects increases. As described above, in the case where the probability of occurrence of a defective sector differs depending on the position on the recording surface, as shown in FIG. 2, it is desirable to configure the cylinder group having a higher probability of occurrence of the defective sector with a smaller number of cylinders. . As a result, the ratio of spare tracks included in the cylinder group increases in accordance with the ratio of occurrence of defects, and accordingly, access to the replacement sector is shortened. Therefore, the spare track can be used more efficiently, and an increase in the response delay time when viewed in the entire disk device can be further suppressed. Also, for example,
When storing data, such as image data and audio data, for which an increase in response delay time needs to be suppressed as much as possible, the spare cylinder can be configured by configuring cylinder groups near those data to be stored with fewer cylinders. The ratio of the track is increased, and the alternative sector can be accessed in a shorter time.

In FIG. 2, four spare tracks are evenly arranged on each of the four recording surfaces in zone 1, but they may not be evenly arranged. However, even when data cannot be recorded or reproduced on a certain recording surface due to, for example, a head failure or the like, in order to secure an available spare track, each of the plurality of recording surfaces is substantially It is desirable to arrange an equal number of spare tracks.

Next, the operation of the HDC 180 for selecting a spare track for allocating a replacement sector will be described with reference to the flowchart shown in FIG.

When the HDC 180 determines that an error has occurred during recording or reproduction for a certain sector and that the error is irrecoverable and needs to be reassigned (step S30), first, the HDC 180 determines whether the cylinder in which the spare track exists exists. Among them, a plurality of cylinders existing in the same zone as the zone where the defective sector exists and in the adjacent zone are selected as cylinder candidates (step S31). A cylinder having a cylinder number having the smallest difference from the cylinder number of the cylinder in which the defective sector exists is selected from the cylinder candidates (step S32). In the cylinder selected in step S32, a recording surface on which a spare track exists is selected (step S33), and it is confirmed whether the selected spare track can be used (step S34).
If the selected spare track is available in step S34, a reassignment process is performed on the spare track (step S35). In step S34, if the selected spare track has already been used by reassignment processing and cannot be used, the cylinder in which the selected spare track exists is excluded from the cylinder candidates (step S36). ), The process returns to step S32, and the above operation is repeated until a usable spare track is determined.

Through the above steps, a spare track which can be accessed from a defective sector in the shortest time and which can be used can be selected.

In the above description, step S3
The cylinder candidate to be selected in step 1 is to select a plurality of cylinders in the same zone as the zone where the defective sector exists and in the adjacent zone from among the cylinders in which the spare track exists, as a cylinder candidate. However, the present invention is not limited to this. For example, all cylinders in the disk device having spare tracks may be used as cylinder candidates.

In the first embodiment, the disk device has two disks and four recording surfaces. However, the disk device may have one or three or more disks. The number of surfaces is not limited to four. In these cases, a spare area can be allocated and a spare sector for allocating a substitute sector can be selected in the same manner.

The operation of arranging a spare track or the operation of selecting a spare track for arranging an alternate sector by the HDC 180 described above is performed in each of H
The program may be installed in a ROM in the DC 180 as a program in advance and executed. Alternatively, for example, the program may be executed from outside the HDC 180 via a recording medium or the like.
A configuration in which the program is read into the RAM in the DC 180 and executed, or a configuration in which the computer is connected to a disk device and controlled by a device external to the HDC 180 may be used.

As described above, according to the first embodiment,
By dividing a plurality of recording surfaces into a plurality of cylinder groups and allocating one spare track to each of the divided cylinder groups, a spare area is accessed mainly from a defective sector by using head switching. Therefore, the head seek time required to access the alternative sector can be further reduced. Therefore, an increase in the response delay time is suppressed, and as a result, the capacity of the spare track can be further reduced, so that the disk use efficiency can be improved.

(Second Embodiment) FIG. 4 is a block diagram showing a configuration of a disk drive according to a second embodiment.
In FIG. 4, the disk device is a disk 110
a, 110b, the disk rotating shaft 130, and the motor 14
0, heads 150a, 150b, 150c, 150d
, An actuator arm 160, a VCM 170,
HDC480. The disk 110a has recording surfaces 120a and 120b, and the disk 110b
It has recording surfaces 120c and 120d. Note that FIG. 4 differs from FIG. 1 only in the method of arranging a spare area and the method of allocating a substitute sector during reassignment processing by HDC 480, and the other components are denoted by the same reference numerals.

Hereinafter, the operation of the second embodiment will be described. However, in the operation of the present embodiment, the first
Only the method of arranging the spare area and the method of allocating the replacement sector are different from those of the second embodiment. Therefore, the other operations are omitted. The method of arranging the replacement sectors will be described in order.

FIG. 5 is a conceptual diagram showing a method of arranging a spare area in the second embodiment. In the second embodiment, as in the first embodiment, it is assumed that the disk device adopts the ZBR system. In FIG. 5, in particular, the outermost one of the plurality of divided zones is used. Although only the zone 1 is shown, spare areas are similarly arranged in other zones.

As shown by the hatched portion in FIG.
a, a spare area a is arranged in the recording surface 120a.
b, a spare area b is arranged on the recording surface 120c, and a spare area d is arranged on the recording surface 120d.

FIG. 6 is a diagram schematically showing the relationship of the arrangement of the spare area between the four recording surfaces shown in FIG. Hereinafter, with reference to FIGS. 5 and 6, a method of arranging spare sectors in the second embodiment will be described in detail.

First, for a certain track, a spare area is prepared continuously for several sectors. Next, in order to access the spare area on the other recording surface in the same cylinder from this spare area in a shorter time, the spare area on the other recording surface in the same cylinder is expressed by the following equation. Are shifted by the angle A shown in FIG.

The angle at which the disk rotates while the head is switched is H degrees, the number of recording surfaces on which spare sectors are arranged in the cylinder is M, and the angle of the prepared spare area with respect to the center of the disk is S degrees. Then, for a positive integer L that satisfies 360 (L−1) <M (S + H) ≦ 360L, A = 360L / M.

For example, when H is set to 80, M is set to 4, and S is set to 1, A = 90 from the above equation, and the spare sectors are shifted by 90 degrees.

According to this method, the same operation was performed for other cylinders. As a result, as shown in FIGS. 4 and 5, in any cylinder, the spare area arranged on the recording surface 120b was arranged on the recording surface 120a. The disc is arranged at a position rotated by 90 degrees with respect to the spare area, and the spare area arranged on the recording surface 120c is
The disk is arranged at a position rotated by 90 degrees with respect to the spare area arranged at the recording surface 120d, and the spare region arranged at the recording surface 120d is rotated at 90 degrees with respect to the spare region arranged at the recording surface 120c. As a result, the spare area arranged on the recording surface 120a is also arranged at a position where the disk is rotated by 90 degrees with respect to the spare area arranged on the recording surface 120d.

The effect of arranging the spare area as described above will be described. In the above formula, L is
It means the minimum number of disk rotations required from continuous access to all spare areas existing in the same cylinder without waste until returning to the first spare area.
A indicates an angle obtained by equally dividing the entire disk rotation angle corresponding to the minimum disk rotation number by the number of spare areas. By arranging the spare areas on each recording surface by the angle A obtained in this way, starting from an arbitrary spare area in a certain cylinder, the spare area is shifted to the other spare area arranged by the angle A. By accessing sequentially, all spare areas in the same cylinder can be accessed in a short time without waste.

Such an arrangement method is a case in which reassignment processing is performed on defective sectors that have occurred continuously and collectively. All of the replacement sectors can be arranged only with the spare area existing in one track. This is particularly effective when it is necessary to arrange a replacement sector in a spare area of one or more other recording surfaces. For example, if a plurality of spare areas in the same cylinder are arranged without shifting the angle with respect to the center of the disk, one disk needs to be accessed to access the next spare area from one spare area.
You have to wait for it to spin. On the other hand, when a plurality of spare areas in the same cylinder are arranged at an angle A apart from each other as in the present embodiment, the next spare area can be accessed only by the time when the disk rotates A degrees. It is possible. Furthermore, even when it is necessary to perform reassignment processing by continuously using all the spare areas in the same cylinder, it is possible to access all the spare areas in order each time the disk rotates A degrees. It is.

In the present embodiment, for the same reason as in the first embodiment, the spare sectors are arranged so that the number of spare sectors is larger inside each zone, and the spare areas are equally distributed on the four recording surfaces. , But are not limited to these arrangements as described in the first embodiment.

Next, the operation of HDC 480 for selecting an alternative sector for performing reassignment processing will be described.
This will be described with reference to the flowchart shown in FIG.

When the HDC 480 determines that an error has occurred during recording or reproduction for a certain sector and that the error is irrecoverable and requires reassignment processing (step S 70), it first enters the same track as the defective sector. It is checked whether the existing spare sector is usable (step S71). In step S71, if a spare sector on the same track is available,
A reassignment process is performed on the spare sector (step S74), and the process ends.

On the other hand, in step S71, if a spare sector on the same track has already been used by the reassignment process and cannot be used, another spare sector existing in the same cylinder as the defective sector is determined. Also, it is checked whether a spare sector located at a position separated from the defective sector by an angle A or more in the disk rotation direction and the opposite direction can be used (step S).
72). In step S72, the angle with the defective sector is set to A in the disk rotation direction and the opposite direction.
The reason for limiting to the spare sector located at a position more than one degree apart is to suppress the time required to access and return from the defective sector to the alternative sector for one rotation of the disk. If the spare sector is available in step S72, a reassignment process is performed on the spare sector (step S74), and the process ends.

On the other hand, if it is determined in step S72 that the spare sector in the same cylinder, which is separated from the defective sector by an angle A or more, cannot be used, other spare sectors exist within the angle A from the defective sector. It is checked whether a spare sector in the same cylinder and a spare sector existing in a different cylinder from the defective sector can be used (step S73). In step S73, when a usable spare sector is confirmed, terrier sign processing is performed on the spare sector (step S74).
The process ends. On the other hand, if no usable spare sector can be confirmed in step S73, the reassignment process is determined to be impossible and the process ends.

By the above steps, the replacement sector is
It is preferentially placed in a spare area that can be accessed and returned from a defective sector during one rotation of the disk. Therefore, an increase in the response delay time of the disk device due to access to the substitute sector can be minimized. Further, even when the number of replacement sectors required for the reassignment process is not enough for the spare sector existing in one track, the spare sector on another recording surface in the same cylinder can be used only by switching the head. The number of spare sectors prepared for one track can be suppressed, and a decrease in disk use efficiency can be suppressed.

In this embodiment, the spare sectors are arranged in all the tracks. However, there may be a track where no spare sector is arranged, for example, when a large capacity of the spare sector is not required. Further, the spare sectors to be arranged in one track are collectively arranged in one place, but they may be divided and arranged in the track. In particular, the case where a plurality of zones are provided on the recording surface of the disk by the ZBR method has been described.
The method may not be used, that is, the disk recording surface may be composed of a single zone.

Further, in the present embodiment, the arrangement of the spare areas is performed in the order of arrangement of the recording surfaces of the disks. Also, the case where the recording surface of the disc has four surfaces is dealt with, but it may be two, three or five or more surfaces. In addition, the arrangement of the spare track and the arrangement of the replacement sector are as follows.
Although it is assumed that the HDC 480 performs the operations, these operations may be performed in a form in which the operations are incorporated in a ROM in the HDC 480 as a program in advance, or may be implemented in a RAM in the HDC 480 via a recording medium. May be used. Furthermore, HDC4
It may be in the form of being controlled by a device external to the device 80, for example, a computer connected to the disk device.

As described above, according to the second embodiment,
Since the spare area exists in every track, it is possible to access the spare area from any defective sector without switching the head or performing head seek.
Therefore, it is possible to reduce the response delay time of the disk device by a time corresponding to one rotation of the disk. Further, since the spare areas arranged on the plurality of recording surfaces are arranged at a distance equal to or longer than the rotation angle of the disk during the time required for switching the heads, it is necessary to perform reassignment processing for a plurality of defective sectors. Even when a spare sector cannot be arranged only by a spare area existing in a track, a spare sector can be arranged by sequentially accessing a plurality of spare areas existing on different recording surfaces in the same cylinder without waste. it can. Therefore, the increase in the response delay time can be suppressed, and at the same time, the capacity of the spare track can be reduced, so that the use efficiency of the disk can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a disk device according to a first embodiment of the present invention.

FIG. 2 is a conceptual diagram of a cross section of a disk for showing an arrangement position of a spare area according to the first embodiment of the present invention.

FIG. 3 is a flowchart showing an operation of the HDC when selecting a spare track for allocating a substitute sector at the time of reassignment processing in the first embodiment of the present invention.

FIG. 4 is a block diagram illustrating a configuration of a disk device according to a second embodiment of the present invention.

FIG. 5 is a perspective view showing an arrangement position of a spare area according to a second embodiment of the present invention.

FIG. 6 is a schematic diagram showing an arrangement position of a spare area according to a second embodiment of the present invention.

FIG. 7 is a flowchart showing an operation of the HDC when selecting a spare sector for allocating a substitute sector at the time of reassignment processing in the second embodiment of the present invention.

FIG. 8 is a conceptual diagram of a cross section of a disk for showing an arrangement position of a spare area in a conventional disk device.

[Explanation of symbols]

 110a, 110b: Disk 120a, 120b, 120c, 120d: Recording surface 130: Disk rotation axis 140: Motor 150a, 150b, 150c, 150d: Head 160: Actuator arm 170: VCM 180, 480: HDC

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hirofumi Yokota 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F term (reference) 5D044 CC04 CC09 DE02 DE03 DE62 DE63 DE76

Claims (18)

[Claims] 1. A disk device for performing reassignment processing on an unrecoverable defective sector, comprising: a disk-shaped recording means including at least one disk-shaped recording medium and having a plurality of recording surfaces as a whole; A disk drive unit for rotating a disk-shaped recording medium; a plurality of heads provided corresponding to each of the plurality of recording surfaces, for recording or reproducing data on the corresponding recording surface; and the plurality of heads And a spare area arranging means for arranging a spare area for arranging a substitute sector for the defective sector in the reassignment processing at different positions on the plurality of recording surfaces. 2. The spare area arranging means, wherein the spare areas are arranged so as to be shifted from each other in the radial direction of the disk-shaped recording medium with respect to each of the plurality of recording surfaces. 2. The disk device according to 1. 3. Data is stored in sector units on each of the plurality of recording surfaces. On each of the recording surfaces, a plurality of sectors existing at an equal distance from a center of rotation are collected. A plurality of tracks that are equidistant from the center of rotation on each of the recording surfaces, each of which collectively forms one cylinder; 3. The disk drive according to claim 2, wherein the means arranges a spare track having a whole area of the track as a spare area on a track on a different cylinder for each recording surface. 4. A plurality of cylinders defined on each recording surface are classified into a plurality of cylinder groups, and cylinders on which the spare tracks are arranged for each recording surface are different from each other. The disk device according to claim 3, wherein the disk device belongs to a cylinder group. 5. The spare area arranging means, wherein the spare areas are arranged so as to be shifted from each other in the rotation direction of the disk-shaped recording medium with respect to each of the plurality of recording surfaces. 2. The disk device according to 1. 6. A plurality of recording surfaces each storing data in sector units, wherein the spare area arranging means sets the spare area in a different angular range from the center of rotation for each of the recording surfaces. 6. The disk device according to claim 5, wherein said disk device is arranged in said sector. 7. The disk device according to claim 6, wherein an angle range in which the spare area is arranged for each of the recording surfaces is separated by a predetermined angle or more for each of the recording surfaces. . 8. The disk device according to claim 7, wherein the predetermined angle is an angle at which the disk-shaped recording medium rotates during a time required for switching the head. 9. A spare sector arranging means for arranging the spare sector for the defective sector with respect to the spare area which can be accessed from the defective sector in the shortest time and is usable. Item 1
9. The disk device according to any one of items 1 to 8. 10. In a disk device including one or more disk-shaped recording media and having disk-shaped recording means having a plurality of recording surfaces as a whole, a reassignment for allocating a substitute sector for an unrecoverable defective sector in a spare area. A reassignment method, comprising: arranging the spare area at different positions on the plurality of recording surfaces; and arranging the replacement sector in the spare area. 11. The step of arranging the spare areas, wherein the spare areas are arranged so as to be shifted from each other in the radial direction of the disk-shaped recording medium with respect to each of the plurality of recording surfaces. The reassignment method according to claim 10. 12. Each of the plurality of recording surfaces stores data in sector units, and in each of the plurality of recording surfaces, the plurality of sectors existing at the same distance from the center of rotation are aggregated. A plurality of tracks that are at the same distance from the center of rotation on each of the recording surfaces, each collectively form one cylinder, and the spare area is 12. The reassignment method according to claim 11, wherein, in the arranging step, a spare track having a whole area of the track as a spare area is arranged on a track on a different cylinder for each of the recording surfaces. 13. The method according to claim 13, further comprising: classifying the plurality of cylinders defined on each of the recording surfaces into a plurality of cylinder groups, wherein the cylinders on which the spare tracks are arranged for each of the recording surfaces are mutually 13. The reassignment method according to claim 12, wherein the reassignment methods belong to different cylinder groups. 14. The step of arranging the spare area, wherein the spare area is arranged so as to be shifted from each other in the rotation direction of the disk-shaped recording medium with respect to each of the plurality of recording surfaces. The reassignment method according to claim 10. 15. The method according to claim 15, wherein data is stored in sector units on each of the plurality of recording surfaces, and the step of arranging the spare area differs for each of the recording surfaces from the center of rotation. The reassignment method according to claim 14, wherein the reassignment is performed in the sector of an angular range. 16. The reassignment method according to claim 15, wherein an angle range in which the spare area is arranged for each of the recording surfaces is separated by a predetermined angle or more for each of the recording surfaces. . 17. The disk drive, wherein the predetermined angle is an angle at which the disk-shaped recording medium rotates in a time required for switching heads in the disk device.
The reassignment method according to claim 16. 18. The step of arranging the replacement sector includes arranging the replacement sector for the defective sector in the spare area that can be accessed from the defective sector in the shortest time and is available. The reassignment method according to any one of claims 10 to 17, wherein: