JPH0850766A - Alternate processing method in information storage - Google Patents

Abstract

PURPOSE:To reduce time for accessing the alternating sector of a defective sector. CONSTITUTION:When a defective sector occurs at the user region of a storage, the alternating sector at an exchange region closest to the defective sector is retrieved, it is judged whether the retrieved exchange sector is available or not, and then the alternate processing is performed when the exchange sector is available, thus reducing the access distance to the sector.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a storage medium replacement processing method in an information storage device such as a magneto-optical disk device or a hard disk device.

[0002]

2. Description of the Related Art A magneto-optical disk having a plurality of groups each having a user area composed of a plurality of sectors to which data is written by a user and a replacement area composed of a plurality of replacement sectors for replacement processing of defective sectors in the user area, There is an information storage device such as a magneto-optical disk or a hard disk device that writes data to a storage medium such as a hard disk and reads the data stored in the storage medium. In such an information storage device, when a defective sector in which data cannot be written occurs in the user area of the storage medium, a replacement process of writing data in a spare sector in the spare area is performed.

In the conventional replacement processing method for a defective sector, a free replacement sector is searched from the beginning of the replacement area corresponding to the user area provided behind the user area to which the defective sector belongs, and the empty replacement sector is searched. Data was written in (for example, Japanese Patent Laid-Open No. 2-3566).
(See Japanese Patent Publication No. 3).

FIG. 29 is a flow chart showing the conventional replacement process. In step (“S” in the figure) 61,
When a defective sector is generated in the user area, the process proceeds to step 62 and the rear area is sequentially backward from the replacement area of the group to which the defective sector belongs, that is, the first replacement sector of the replacement area corresponding to the user area in which the defective sector has occurred. The vacant replacement sector is searched, and if there is a vacant replacement sector in step 63, the process proceeds to step 66 to perform the replacement process on the vacant replacement sector.

However, if it is determined in step 63 that there are no spare replacement sectors, the process proceeds to step 64, in which the spare sectors are sequentially searched backward from the first spare sector in the spare area of the rear group. If there is no vacant replacement sector in step 65, the process returns to step 64 again to search for a replacement region in a group further behind, and if there is a vacant replacement region, the process proceeds to step 66 and becomes vacant. The replacement process is performed on the replacement sector, and this process ends.

[0006]

However, in the replacement processing method in the above-described information storage device, when a defective sector occurs near the beginning of the user area, the replacement area slightly distant from the defective sector is vacant. Since the replacement sector is searched for and the replacement process is performed on the vacant replacement sector, there is a problem that the seek time for accessing the replacement sector becomes long.

If all the replacement sectors in the replacement area corresponding to the user area to which the defective sector belongs have been used, the replacement processing is performed on the replacement area of the group immediately preceding the group of the user area and the replacement area. By doing so, a vacant replacement sector is searched from the beginning of the replacement area, and replacement processing is performed on the vacant replacement sector, so the replacement sector is used from a replacement sector distant from the defective sector. There has been a problem that the seek time for accessing the replacement sector becomes long when accessing a group of consecutive logical addresses including the logical address corresponding to the replacement sector.

Further, all the replacement sectors in the replacement area corresponding to the user area in which the defective sector has occurred have been used,
Furthermore, if all the replacement sectors of the replacement areas of the groups immediately before and after the group of the user area and the replacement area have also been used, it is not possible to determine which replacement area should be used next. In some cases, the replacement sector in the replacement area distant from the sector is used, and in such a case, there is a problem that the seek time for accessing the replacement sector becomes long.

Further, defective sectors are concentrated in the first half of a certain user area, and all the replacement sectors of the replacement area of the group immediately before that user area are used, and all the replacement areas of the immediately preceding group are replaced. When a sector has already been used, when a defective sector occurs in the user area of the group immediately before the user area where the defective sector occurs, the second spare area is used regardless of before or after the user area. Therefore, there is a problem that the seek time for accessing the replacement sector becomes long.

Furthermore, when searching for a free replacement sector in the replacement area, if a free replacement sector is always searched from the beginning of the replacement area, a replacement sector close to the defective sector may be empty depending on the position where the defective sector occurs. However, there is a problem that the replacement process may be performed on the replacement area at a farther distant position, and the seek time for accessing the replacement sector becomes longer.

The present invention has been made in view of the above points, and it is an object of the present invention to shorten the time for accessing a replacement sector of a defective sector.

[0012]

In order to achieve the above-mentioned object, the present invention comprises a user area composed of a plurality of sectors in which a user writes data, and a plurality of replacement sectors for replacement processing for defective sectors in the user area. Writing means for writing data to a storage medium having a plurality of groups each having an alternate area, read means for reading data stored in the storage medium, and writing means for writing the data in the user area. When a defective sector in which data cannot be written occurs, in an information storage device equipped with a replacement processing means for writing data to the spare sector in the spare area, the spare area closest to the defective sector Provided is a replacement processing method for performing replacement processing on existing replacement sectors.

Further, in the above information storage device, when all the replacement sectors of the replacement area of the group to which the generated defective sector belongs have been used, the replacement areas of the other groups closest to the defective sector are stored. The spare process may be performed on the spare sector that is vacant.

Further, when all the replacement sectors in the replacement area of the group immediately before and immediately after the group to which the generated defective sector belongs have been used, the defective sector is closest to the defective sector. The spare processing may be performed on a spare sector in the spare area of the group.

In the information storage device as described above, each of the replacement areas is divided into a first half area and a second half area so that the number of replacement sectors is halved, and the replacement area immediately before the defective sector is generated. If the spare area in the closest one of the latter half area and the first half area of the immediately following spare area is replaced, and there is no spare replacement area in any of the areas, the immediately previous spare area There is also provided a replacement processing method for performing replacement processing on a vacant replacement sector in the closest one of the first half area and the second half area immediately after the replacement area.

Further, when there is no vacant replacement sector in either the replacement area immediately before or immediately after the defective sector that has occurred, the replacement area in the front and the replacement area in the rear are closest to each other. When the spare processing is performed on the spare area in the other area and there is no spare sector in any of the areas, the first half area of the front spare area and the rear half area of the rear spare area are the most The spare process may be performed on the spare sector in the nearer area.

Then, in each of the replacement processing methods described above,
In the spare area in front of the defective sector that has occurred, the spare area is searched sequentially from the last spare sector in the spare area toward the front, and in the spare area in the rear, from the first spare sector in the spare area to the rear. It is advisable to search for available spare sectors in sequence.

[0018]

In the replacement processing method in the information storage device according to the present invention, the replacement processing is performed on the free replacement sector in the replacement area closest to the generated defective sector. Therefore, the defective sector and the replacement sector subjected to the replacement processing are replaced. The access distance can be minimized, and the seek time for accessing the replacement sector can be shortened. This is particularly effective when the number of sectors in the user area is large and the distance between the first sector and the last sector is large.

Further, when all the replacement sectors in the replacement area of the group to which the generated defective sector belongs have been used, the replacement processing is performed on the vacant replacement sector of the replacement area of the other group closest to the defective sector. By doing so, even when all the replacement sectors in the replacement area of the group to which the defective sector belongs are not vacant, the access distance between the defective sector and the replacement sector subjected to the replacement processing can be minimized, and The seek time to access can be shortened.

Further, when all the replacement sectors in the replacement area of the group immediately before and immediately after the group to which the generated defective sector belongs have been used, the group closest to the defective sector from the groups further ahead or behind. If the replacement processing is performed on the empty replacement sector in the replacement area, the defective sector and its replacement processing will be performed even if all replacement sectors in the replacement area of the group immediately before and after the group to which the defective sector belongs are not empty. It is possible to shorten the access distance to the replacement sector that has performed the above-mentioned procedure, and to shorten the seek time for accessing the replacement sector.

Further, each replacement area is divided into a first half area and a second half area such that the number of replacement sectors is halved, and the second half area of the replacement area immediately before the defective sector and the first half area of the replacement area immediately after the defective sector. If the spare area in the closest area among them is replaced, and there is no spare sector in any area, the first half area of the immediately previous spare area and the second half area of the immediately following spare area If the spare sector in the closest one of the areas is subjected to the spare processing, the distance between the defective sector generated in each user area and the spare sector can be shortened in the same manner. It is possible to minimize the access distance between the sector and the replacement sector that has performed the replacement process,
The seek time for accessing the replacement sector can be shortened.

Further, when there is no vacant replacement sector in either of the replacement areas immediately before and immediately after the defective sector that has occurred, the replacement area in the front and the replacement area in the rear are closest to each other. When the spare processing is performed on the spare area in the other area, and there is no spare sector in any of the areas, the closest one of the front half area of the front spare area and the rear half area of the rear spare area is the closest. By performing the replacement process on the vacant replacement sector in the other area, even if all replacement sectors in the replacement area immediately before and immediately after the defective sector are not vacant, the defective sector generated in each user area and its replacement are replaced. The distance to the sector can be shortened in the same way, and the access distance between each defective sector and the replacement sector that has undergone the replacement process can be minimized. It is possible to shorten the seek time to access the alternate sector.

Then, in the spare area in front of the generated defective sector, a spare sector sequentially vacant from the last spare sector in the spare area is searched forward, and in the spare area in the rear, the first spare sector in the spare area is searched. By searching for replacement sectors that are vacant in the backward direction, the replacement process can be performed on the replacement sector that is closest to the defective sector even within the replacement area, and the defective sector and the replacement sector that has performed the replacement process can be used. Access distance can be minimized, and seek time for accessing the replacement sector can be shortened.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be specifically described below with reference to the drawings. FIG. 2 is a block diagram showing the configuration of the information storage device of one embodiment of the present invention. This information storage device 1 allows a user to write data on a storage medium 2 such as a magneto-optical disk for storing various data and a recording surface of the storage medium 2, or to read data stored on the recording surface. CPU 4 which is a microcomputer which controls the read / write controller 3 and the information storage device 1 as a whole, and which performs a replacement process and the like according to the present invention.
It has.

Further, a program ROM storing various programs for the CPU 4 to perform various processes.
5, a RAM 6 which is a storage area used when the CPU 4 performs various processes, and an interface (I / F) 7 for exchanging data with a host device such as a personal computer.

Therefore, the read / write controller 3
Serves as a writing unit that writes data to the storage medium 2 and a reading unit that reads the stored data. Further, the CPU 4 is a replacement processing unit that, when a defective sector in which data cannot be written occurs in the user area of the storage medium 2, performs replacement processing for writing data in an empty replacement sector in the replacement area closest to the defective sector. Perform a function.

Next, the replacement process in this information storage device will be described. FIG. 1 is a flowchart showing a replacement process in the information storage device 1. This process
When a defective sector occurs in the user area of the storage medium in step 1 (indicated by "S" in the figure), the process proceeds to step 2 and the replacement sector in the replacement region closest to the defective sector is searched for, and the process proceeds to step 3. In step 3, it is judged whether or not the spare sector searched in step 2 is free. If it is not free, the process returns to step 2, and if it is free, the process proceeds to step 4 to perform the spare processing on the free spare sector. Then, the process is finished.

In other words, in this processing, when a defective sector occurs in the user area, a vacant replacement sector is searched from among the respective replacement sectors in the replacement area closest to the defective sector, and data is written in the vacant replacement sector. Alternate processing to write

Next, the above replacement process will be described in more detail. FIG. 3 is an explanatory diagram showing an example of the format of the recording surface of the storage medium 1. As shown in FIG. 3A, the recording surface of the storage medium has a user area A to N composed of a plurality of sectors in which a user writes data, and a plurality of replacement processes for defective sectors in each of the user areas A to N. Groups A to N having spare areas a to n made up of spare sectors for use.

Further, as shown in FIG. 3B, the replacement area a of the user area A has ten replacement sectors sa0 to sas.
It consists of a9. The user area B has 40 sectors b0 to b
The replacement area b is composed of 10 replacement sectors sb0.
~ Sb9. User area C has 40 sectors c0
~ C39, the replacement area c is composed of 10 replacement sectors s.
It consists of c0 to sc9. The user area D is composed of 40 sectors d0 to d39, and the spare area d is composed of 10 spare sectors sd0 to sd9.

Next, a case where the replacement process shown in FIG. 1 is applied to the replacement area shown in FIG. 3 will be described with reference to FIGS. 4 to 7. In FIGS. 4 to 7B, only the sector symbols related to the description are omitted and others are omitted. As shown in FIG. 4B, for example, the user area C
When a defect occurs in the sector c10, the spare processing is performed by searching for a free spare sector in the spare area b closest to the sector c10, as shown in FIG. 5B. For example, replacement processing is performed by searching for replacement sectors that are sequentially open backward from the replacement sector sb0.

As shown in FIG. 6B, when a defect occurs in the sector c28 of the user area C, as shown in FIG. 7B, the replacement area c closest to the sector c28 is detected. The vacant replacement sector is searched for and replacement processing is performed. For example, the spare sector is sequentially searched backward from the spare sector sc0, and spare processing is performed.

In this way, in the replacement processing of this information storage device, when a defective sector occurs in the user area, the replacement processing is performed in the free replacement area closest to the defective sector. The seek time when accessing the sector can be shortened.

Next, another embodiment of the present invention will be described. In the information storage device of this embodiment, the CPU function is different from that of the above-described embodiment, and when a defective sector in which data cannot be written occurs in the user area of the storage medium 1, the replacement area closest to the defective sector is In the spare area in front of the defective sector, a spare sector that is sequentially vacant from the last spare sector in the spare area is searched for forward, and in the rear spare area, the spare area is sequentially emptied backward from the first spare sector in the spare area. It performs the function of a replacement processing unit that searches for a new replacement sector and writes the data in the empty replacement sector.

Next, the replacement process will be described with reference to the flowchart of FIG. In this process, when a defective sector is generated in step (indicated by "S" in the figure) 11, the process proceeds to step 12 and, for the replacement area closest to the defective sector, if the replacement area is in front of the defective sector, From the last replacement sector in the replacement area, the replacement sectors are sequentially searched forward, and if the replacement area is the rear replacement area, the replacement sectors are searched sequentially from the first replacement sector in the replacement area backward, and the process proceeds to step 13.

In step 13, it is judged whether or not the retrieved replacement sector is vacant. If it is not vacant, the process returns to step 12, and if it is vacant, the process proceeds to step 14 and the vacant replacement sector is replaced. Then, this process is finished.

In other words, in this processing, when a defective sector occurs, in the replacement area in front of the defective sector with respect to the replacement area closest to the defective sector, sequentially from the last replacement sector in the replacement area to the front. Search for a vacant replacement sector, and in the rear replacement area, search for replacement sectors that are sequentially vacant from the first replacement sector in the replacement area toward the rear, and perform replacement processing to write data to the vacant replacement sector. .

Next, the replacement process will be described in more detail with reference to FIGS. For example, in FIG.
As shown in FIG. 5, when a defect occurs in the sector c10 of the user area C, as shown in FIG. 5B, the last replacement sector sb of the replacement area b closest to this sector c10.
The spare sector is sequentially searched for from 9 to the front, and spare processing is performed.

As shown in FIG. 6B, when a defect occurs in the sector c28 of the user area C, as shown in FIG. 7B, the replacement area closest to this sector c28. Replacement processing is performed by searching for replacement sectors that are sequentially vacant from the first replacement sector sc0 of c toward the rear.

In this way, in the replacement processing of this information storage device, when a defective sector occurs in the user area, the vacant replacement sector is closer to the defective sector than the replacement area closest to the defective sector. Since the replacement sectors are sequentially searched, the vacant replacement sector closest to the defective sector can be found first and the replacement process can be performed.

Next, still another embodiment of the present invention will be described. In the information storage device of this embodiment, the CPU function is different from that of the above-mentioned embodiment, and when all the replacement sectors of the replacement area of the group to which the defective sector generated in the user area of the storage medium 1 belongs have been used, The spare sector in the spare area of the other group closest to the defective sector is subjected to spare processing, and all spare sectors in the spare area of the group immediately before and after the group to which the generated defective sector belongs have also been used. At this time, it performs the function of a replacement processing means for performing replacement processing on the spare sector in the spare area of the nearest group from the groups further ahead or behind the defective sector.

Next, the replacement process will be described with reference to the flowchart of FIG. In this processing, when a defective sector occurs in the user area of the storage medium 1 in step (indicated by "S" in the figure) 21, the process proceeds to step 22 and a spare sector in the spare area of the group to which the defective sector belongs is vacant. Is searched and it is determined in step 23 whether or not there is a free replacement sector. If there is a free replacement sector, the process proceeds to step 28.

If it is determined in step 23 that there is no free replacement sector, the process proceeds to step 24, in which the replacement area of the group closer to the defective sector in the groups immediately before and immediately after the group to which the defective sector belongs is vacant. The spare sector is searched for, the process proceeds to step 25, it is judged whether or not there is a spare sector that is vacant, and if there is a spare sector that is vacant, the process proceeds to step 28.

If it is determined in step 25 that there is no spare sector in the spare area of the groups immediately before and immediately after, the process proceeds to step 26 and the group closest to the defective sector is replaced with the group closest to the defective sector. The spare sector in the area is searched for, and the process proceeds to step 27, where it is judged whether or not there is a spare spare sector. If there is a spare spare sector, the process proceeds to step 28, but it is free. If there is no replacement sector, the process returns to step 26 to search for a free replacement sector in another group. Then, in step 28, the spare sector is subjected to the spare processing, and this processing is finished.

In other words, in this process, when a defective sector occurs, first, the spare area of the group to which the defective sector belongs, that is, the spare area in the spare area corresponding to the user area in which the defective sector has occurred, is vacant. If there is a spare sector that has been found and is free, the spare sector is replaced.

However, if all the replacement sectors in the replacement area have been used and there is no spare replacement sector,
Next, an empty spare sector in the spare area of the group immediately before and immediately after the group to which the defective sector belongs is searched for, and if there is a spare sector, the spare sector is replaced.

Furthermore, if all the replacement sectors in each replacement area of the groups immediately before and immediately after that have been used and there is no spare replacement sector, the group before or after the defective sector is selected. A vacant replacement sector in the replacement area of the closest group is searched for, and if there is a vacant replacement sector, replacement processing is performed on the replacement sector.

Next, the replacement process will be further described in detail with reference to FIGS. 4 to 7 and FIGS. 10 to 15. Also in FIG. 10 to FIG. 15B, only the sector symbols related to the description are shown and the others are omitted.

For example, as shown in FIG. 4B, when a defect occurs in the sector c10 of the user area C, as shown in FIG.
As shown in (b) of 0, a vacant replacement sector in the replacement area c of the group C to which the sector c10 belongs is searched for and replacement processing is performed. For example, replacement processing is performed by searching for replacement sectors that are sequentially vacant from the first replacement sector sc0 toward the rear.

Further, each replacement sector sc of the replacement area c
When all of 0 to sc9 have been used, as shown in FIG. 5B, the group C to which the sector c10 belongs
The spare area in the spare area b of the group B immediately before is searched for and the spare processing is performed. For example, replacement processing is performed by searching for replacement sectors sequentially vacant from the first replacement sector sb0 toward the rear.

Further, each replacement sector s in the replacement area b
When all of b0 to sb9 are also used, as shown in FIG.
(B), the spare processing is performed by searching for a free spare sector in the spare area a of the group A closest to the group c to which the sector c10 in which the defect has occurred next. For example, replacement processing is performed by searching for replacement sectors that are sequentially vacant from the first replacement sector sa0 toward the rear.

When there is no free replacement sector in the replacement area a, as shown in FIG.
Next, the spare processing is performed by searching for a free spare sector in the spare area d of the group D closest to the group c to which the defective sector c10 belongs. For example, replacement processing is performed by searching for replacement sectors that are sequentially vacant from the first replacement sector sd0 toward the rear.

Thus, when all the spare areas of the spare area of the group to which the defective sector belongs and the spare area of the spare area of the immediately preceding group have been used, the spare area of the group closest to the front or rear group is free. Since a replacement sector that is present is searched for, the replacement process can be performed on the empty replacement sector in the closest replacement area from the defective sector.

Alternatively, as shown in FIG. 6B,
When a defect occurs in the sector c28 of the user area C, as shown in FIG. 7B, an empty spare sector in the spare area c of the group C to which the sector c28 belongs is searched for and the spare processing is performed. For example, replacement processing is performed by searching for replacement sectors that are sequentially vacant from the first replacement sector sc0 toward the rear.

All replacement sectors sc in the replacement area c
When 0 to sc9 have been used, as shown in (b) of FIG. 13, the group C to which the sector c28 belongs
The spare area in the spare area b of the group B immediately before is searched for and the spare processing is performed. For example, replacement processing is performed by searching for replacement sectors sequentially vacant from the first replacement sector sb0 toward the rear.

Further, each replacement sector s in the replacement area b
When all of b0 to sb9 are also used,
(B), the spare processing is performed by searching for a free spare sector in the spare area d of the group D closest to the group c to which the sector c28 in which the defect has occurred next. For example, replacement processing is performed by searching for replacement sectors that are sequentially vacant from the first replacement sector sd0 toward the rear.

When there is no free replacement sector in the replacement area d, as shown in FIG.
Next, the spare processing is performed by searching for a free spare sector in the spare area a of the group A closest to the group c to which the defective sector c28 belongs. For example, replacement processing is performed by searching for replacement sectors that are sequentially vacant from the first replacement sector sa0 toward the rear.

In this way, when the replacement area c of the group to which the defective sector belongs and the replacement sector of the replacement area of the group immediately after that are all used, the closest replacement is made from the front or rear group. Since an empty spare sector in the spare area of the group is searched, the spare processing can be performed to the spare spare area in the spare area closest to the defective sector.

Next, still another embodiment of the present invention will be described. In the information storage device of this embodiment, the CPU
The function of is different from that of the above-described embodiment, when all the replacement sectors of the replacement area of the group to which the defective sector generated in the user area of the storage medium 1 has been used, When the spare sector in the spare area is subjected to the spare processing, and all spare sectors in the spare area of the group immediately before and after the group to which the defective sector belongs are also in use, the sector further ahead of the defective sector. Alternate processing is performed on the vacant replacement sector in the replacement area of the group closest to the rear group, but in this case, in the replacement area in front of the defective sector that occurred, the replacement sector is sequentially replaced from the last replacement sector toward the front. A sector is searched for, and in the rear spare area, it functions as a spare processing unit that sequentially searches for a spare sector from the first spare sector toward the rear.

Next, the replacement process will be described with reference to the flowchart of FIG. In this process, when a defective sector is generated in the user area of the storage medium 1 at step (indicated by "S" in the figure) 31, the process proceeds to step 32 and the first replacement sector in the replacement area of the group to which the defective sector belongs is started. When the spare sectors are vacant, a search is made sequentially for spare spare sectors toward the rear, and the process proceeds to step 33 to determine whether there is a spare spare sector.
Go to step 38.

If it is determined in step 33 that there is no spare replacement sector, the process proceeds to step 34, in which the replacement area of the group closest to the defective sector in the groups immediately before and immediately after the group to which the defective sector belongs is selected. Immediately after, the spare area of the group searches forward from the first spare sector, and the spare area of the group immediately before searches for spare sectors that are sequentially open backward from the last spare sector.
In step 35, it is judged whether or not there is a spare spare sector, and if there is a spare spare sector, the routine proceeds to step 38.

If it is determined in step 35 that there is no spare replacement sector, the process proceeds to step 36, where the first replacement sector in the replacement area of the group closest to the defective sector in front of the defective sector is moved forward. Toward the back, or sequentially from the last replacement sector toward the rear, the spare sectors are searched sequentially, and the process proceeds to step 37 to determine whether or not there is a free replacement sector. For example, the process returns to step 36, and a search for a vacant replacement sector is similarly performed for other groups. On the other hand, if there is a free replacement sector, the process proceeds to step 38. Then, in step 38, the spare processing is performed on the spare sectors that are vacant, and this processing ends.

In this processing, when a defective sector is generated, first, the nearest free spare sector is searched from among the respective spare sectors in the spare area of the group to which the defective sector belongs, and if there is a free spare sector. The replacement processing is performed on the replacement sector.

However, if all the replacement sectors in the replacement area have been used and there is no spare replacement sector, then the nearest replacement in the group immediately before or after the group to which the defective sector belongs is next. The nearest vacant replacement sector is searched from each sector in the area, and if there is a vacant replacement sector, the replacement process is performed on the replacement sector.

Further, when all the replacement sectors in each replacement area of the group immediately before or immediately after that have been used and there is no spare replacement sector, the closest one from the groups further ahead or behind the defective sector. The closest available spare sector is searched from among the respective spare sectors in the spare area of the group, and if there is a spare spare sector, the spare sector is replaced.

Next, the replacement process will be described in more detail with reference to FIGS. 4 to 7 and FIGS. 10 to 15. Also in FIG. 10 to FIG. 15B, only the sector symbols related to the description are shown and the others are omitted.

For example, as shown in FIG. 4B, when a defect occurs in the sector c10 of the user area C,
As shown in (b) of 0, replacement processing is performed by searching for replacement sectors sequentially vacant from the first replacement sector sc0 in the replacement area c of the group C to which the sector c10 belongs.

Further, each replacement sector sc of the replacement area c
When all 0 to sc9 have been used, as shown in (b) of FIG. 5, from the last replacement sector sb9 of the replacement area b of the group B immediately before the group C to which the sector c10 belongs, to the front. Replacement processing is performed by sequentially searching for vacant replacement sectors.

Further, each replacement sector s in the replacement area b
When all of b0 to sb9 are also used, as shown in FIG.
(B), the replacement process is performed by searching for replacement sectors that are sequentially vacant from the last replacement sector sa9 in the replacement area a of the group A closest to the next group c to which the sector c10 belongs. Give.

Furthermore, when there is no free replacement sector in the replacement area a, as shown in FIG. 12B, the group c to which the sector c10 belongs next.
The replacement processing is performed by searching for replacement sectors sequentially vacant from the first replacement sector sd0 in the replacement area d of the group D closest to

In this way, when all the replacement sectors of the replacement area of the group to which the defective sector belongs and the replacement area of the group immediately before that have been used, the group closest to the group further ahead or behind is replaced. The vacant replacement sector in the replacement area is searched, and the vacant replacement sector is searched in order from the replacement sector closest to the defective sector. Replacement processing can be performed on sectors.

Alternatively, as shown in FIG. 6B,
When a defect occurs in the sector c28 of the user area C, as shown in (b) of FIG. 7, the spare area c0 of the group C to which the sector c28 belongs is vacant from the first replacement sector sc0 toward the rear. Search for a replacement sector and perform replacement processing.

Further, each replacement sector sc of the replacement area c
When all of 0 to sc9 have been used, as shown in (b) of FIG. 13, from the last replacement sector sb9 of the replacement area b of the group B immediately before the group C to which the sector c28 belongs, to the front. Replacement processing is performed by sequentially searching for vacant replacement sectors.

Further, each replacement sector s in the replacement area b
When all of b0 to sb9 are also used,
(B), the replacement process is performed by searching for replacement sectors sequentially vacant backward from the first replacement sector sd0 in the replacement region d of the group D closest to the group c to which the sector c28 belongs. Give.

When there is no free replacement sector in the replacement area d, as shown in FIG. 15B, the replacement area of the group A closest to the group c to which the sector c10 belongs next. The last replacement sector sa9 of a
From here, the spare sector is sequentially searched for free spare sectors.

In this way, when all the replacement sectors of the replacement area of the group to which the defective sector belongs and the replacement area of the group immediately after that have been used, the group closest to the group further ahead or behind is replaced. The vacant replacement sector is searched for, and the vacant replacement sector is searched in order starting from the replacement sector closest to the defective sector, so the defective sector is replaced by the closest vacant replacement sector. It can be processed.

Next, still another embodiment of the present invention will be described. In the information storage device of this embodiment, the function of the CPU is different from that of the above-described embodiment, and each replacement area of the storage medium 2 is divided into a first half area and a second half area so that the number of replacement sectors is halved. The replacement process is performed on the vacant replacement sector in the closest one of the second half region of the replacement region immediately before the defective sector and the first half region of the replacement region immediately after the defective sector. If not, it performs the function of a replacement processing unit that performs replacement processing on a vacant replacement sector in the closest one of the first half area of the immediately previous replacement area and the second half area of the immediately following replacement area.

Furthermore, when there is no vacant replacement sector in either the replacement area immediately before or immediately after the defective sector that has occurred, the nearest half of the replacement area in the front and the first half of the replacement area in the rear is the closest. When the spare processing is performed on the spare area in the other area, and there is no spare sector in any of the areas, the closest one of the front half area of the front spare area and the rear half area of the rear spare area is the closest. It also functions as a replacement processing means for performing replacement processing on a spare sector in the other area.

Next, the replacement process will be described with reference to the flowchart of FIG. In this process, when a defective sector occurs in the user area in step (indicated by "S" in the figure) 41, the process proceeds to step 42, in which the latter half area of the replacement area immediately before the defective sector and the first half area of the replacement area immediately after the defective sector are processed. The closest available spare sector is searched for, and the process proceeds to step 43 to determine whether or not the spare sector is free. If there is a free spare sector, the process proceeds to step 50.

If it is determined in step 43 that there is no free replacement sector, the process proceeds to step 44, in which the nearest area of the first half area of the replacement area immediately before the defective sector and the second half area of the replacement area immediately after the defective sector is free. The spare sector is searched for, and the process proceeds to step 45 to determine whether or not the spare sector is empty. If there is a spare sector available, the process proceeds to step 50.

If it is determined in step 45 that there is no free replacement sector, the process proceeds to step 46, in which the latter half of the replacement area immediately before the replacement area immediately before the defective sector and the area further rearward of the replacement area immediately after the defective sector. If the spare sector in the closest one of the first half areas of the spare area is searched for, the process proceeds to step 47, where it is determined whether or not the spare sector is empty. Go to step 50.

If it is determined in step 47 that there is no free replacement sector, the process proceeds to step 48 and the closest one of the front half region of the front spare region and the rear half region of the rear spare region is free. The replacement sector is searched, the process proceeds to step 49, it is judged whether or not the replacement sector is free, and if there is no free replacement sector, the process returns to step 46 and the search process is similarly performed for the front and rear regions. If there is a free replacement sector, step 50
Go to. Then, in step 50, the spare processing is performed on the spare sector that is vacant, and this processing ends.

FIG. 18 is an explanatory diagram showing an example of the format of the recording surface of the storage medium 1 at the time of this replacement processing.
The format of this recording surface is almost the same as the format shown in FIG. 3, but is divided into the first half area and the second half area so that the replacement sectors of each replacement area are halved during the replacement processing. That is, as shown in (b) of the figure, for example, in the replacement area a, the replacement sector s in the first half is used.
It is divided into a0 to sa4 and replacement sectors sa5 to sa9 in the latter half.

Next, the replacement process will be further described in detail with reference to FIGS. 19 to 27. In FIG. 19 to FIG. 27B, only the sector symbols related to the description are shown and the others are omitted.

For example, as shown in FIG. 19B, when a defect occurs in the sector c10 of the user area C,
As shown in (b) of 0, the vacant replacement sector of the second half area of the replacement area b, which is the closest of the second half area of the replacement area b immediately before the sector c10 and the first half area of the replacement area c immediately after it, Search for and perform replacement processing. For example, replacement processing is performed by searching for replacement sectors sequentially vacant from the first replacement sector sb5 toward the rear.

When all the replacement sectors sb5 to sb9 in the second half area of the replacement area b have been used, as shown in FIG. 21B, the first half area of the replacement area c immediately after the sector c10. The vacant replacement sector is searched for and replacement processing is performed. For example, replacement processing is performed by searching for replacement sectors that are sequentially vacant from the first replacement sector sc0 toward the rear.

Further, when all the replacement sectors sc0 to sc4 in the first half area of the replacement area c have also been used, as shown in FIG. 22B, the first half area of the replacement area b immediately before the sector c10. The vacant replacement sector is searched for and replacement processing is performed. For example, for example, replacement processing is performed by searching for replacement sectors sequentially vacant rearward from the first replacement sector sb0.

When all the replacement sectors sb0 to sb4 in the first half area of the replacement area c are also used, as shown in FIG. 23B, the second half area of the replacement area c immediately after the sector c10. The vacant replacement sector is searched for and replacement processing is performed. For example, for example, replacement processing is performed by searching for replacement sectors sequentially vacant from the first replacement sector sc5 toward the rear.

Further, the replacement area b immediately before the sector c10
When there is no vacant replacement sector in any of the replacement areas c immediately after the above, as shown in (b) of FIG. 24, as shown in (b) of FIG. The nearest replacement area a in the first half area
The spare processing is performed by searching for a vacant replacement sector in the latter half area of. For example, replacement processing is performed by searching for replacement sectors that are sequentially vacant from the first replacement sector sa5 toward the rear.

Further, when all the replacement sectors sa5 to sa9 in the latter half area of the replacement area a have been used, as shown in FIG.
The vacant replacement sector in the first half area is searched for and replacement processing is performed. For example, replacement processing is performed by searching for replacement sectors that are sequentially vacant from the first replacement sector sd0 toward the rear.

Further, when there is no vacant replacement sector in either the second half area of the replacement area a or the first half area of the replacement area d, as shown in FIG. The spare processing is performed by searching for a free spare sector in the first half area of the spare area a, which is the closest one of the latter half areas of the spare area d. For example, replacement processing is performed by searching for replacement sectors that are sequentially vacant from the first replacement sector sa0 toward the rear.

Then, when all the replacement sectors sa0 to sa4 in the first half area of the replacement area a are all used, as shown in FIG. 27B, the second half area of the replacement area d is vacant. The replacement sector is searched for and replacement processing is performed. For example, replacement processing is performed by searching for replacement sectors that are sequentially vacant from the first replacement sector sd5 toward the rear.

Alternatively, when a defect occurs in the sector c28 of the user area C, first, the replacement area c, which is the closest of the latter half area of the replacement area b immediately before the sector c28 and the first half area of the replacement area c immediately after the sector c28, is the closest. The spare processing is performed by searching for a free spare sector in the first half area. For example, replacement processing is performed by searching for replacement sectors that are sequentially vacant from the first replacement sector sc0 toward the rear.

When all the replacement sectors sc0 to sc4 in the first half area of the replacement area c are all used, the spare processing is performed by searching for an empty replacement sector in the second half area of the replacement area b immediately before the sector c28. Give. For example, replacement processing is performed by searching for replacement sectors sequentially vacant from the first replacement sector sc5 toward the rear.

Further, when all the replacement sectors sb5 to sb9 in the latter half area of the replacement area b are all used, the empty replacement sector in the latter half area of the replacement area c immediately after the sector c28 is searched for replacement processing. Give. For example, for example, replacement processing is performed by searching for replacement sectors sequentially vacant from the first replacement sector sc5 toward the rear.

When all the replacement sectors sc5 to sc9 in the latter half area of the replacement area c have also been used, the spare processing is performed by searching for an empty replacement sector in the first half area of the replacement area b immediately before the sector c28. Give. For example, for example, replacement processing is performed by searching for replacement sectors sequentially vacant rearward from the first replacement sector sb0.

Further, the replacement area c immediately after the sector c28
When there is no vacant replacement sector in either of the replacement area b and the immediately preceding replacement area b, the replacement area which is the closest of the first half area of the replacement area d further behind the sector c28 and the latter half area of the front replacement area a. The spare processing is performed by searching for a free spare sector in the first half area of d. For example, replacement processing is performed by searching for replacement sectors that are sequentially vacant from the first replacement sector sd0 toward the rear.

Further, when all the replacement sectors sd0 to sd4 in the first half area of the replacement area d are all used, the empty replacement sector in the second half area of the front replacement area a is searched and the replacement processing is performed. For example, replacement processing is performed by searching for replacement sectors that are sequentially vacant from the first replacement sector sa5 toward the rear.

Further, when there is no vacant replacement sector in either the first half area of the replacement area d or the second half area of the replacement area a, the closest one of the second half area of the replacement area d and the first half area of the replacement area a. The spare area is searched for an empty spare sector in the latter half area of the spare area d. For example, replacement processing is performed by searching for replacement sectors that are sequentially vacant from the first replacement sector sd5 toward the rear.

Then, when all the replacement sectors sd5 to sd9 in the second half area of the replacement area d are all used, the empty replacement sector in the first half area of the replacement area a is searched for and the replacement processing is performed. For example, the first replacement sector s
Replacement processing is performed by sequentially searching for replacement sectors that are vacant from a0 to the rear.

In this way, the spare processing can be performed on the spare spare area in the spare area closest to the defective sector, and the spare area around the spare area is used exclusively by the specific user area, and the other spare area is used. It is possible to prevent as much as possible from being able to use only the replacement area away from each other.

Next, still another embodiment of the present invention will be described. In the information storage device of this embodiment, the CPU
Is slightly different from that of the above-described embodiment, each spare area of the storage medium 2 is divided into a first half area and a second half area so that the number of spare sectors is halved, and the spare area immediately before the defective sector is generated. If the spare area in the closest one of the latter half area of the above and the first half area of the immediately following spare area is replaced, and there is no spare sector in any of the areas, the immediately previous spare area Of the first half area and the second half area of the immediately following replacement area, which functions as replacement processing means for performing replacement processing on a free replacement sector in the closest area.

Further, when there is no vacant replacement sector in both the replacement area immediately before and immediately after the defective sector that has occurred, the closest replacement area is the closest to the rear half area of the front replacement area and the rear half area of the rear replacement area. When the spare processing is performed on the spare area in the other area, and there is no spare sector in any of the areas, the closest one of the front half area of the front spare area and the rear half area of the rear spare area is the closest. It also functions as a replacement processing means for performing replacement processing on a spare sector in the other area.

When searching for the vacant replacement sector, replacement sectors in front of the defective sector are searched sequentially for replacement sectors from the last replacement sector to the front, and replacement sectors in the rear are searched for the first replacement sector. It functions as a replacement processing unit that sequentially searches for replacement sectors toward the rear.

Next, the replacement process will be described with reference to the flowchart of FIG. In this process, when a defective sector is generated in the user area in step (indicated by "S" in the figure) 51, the process proceeds to step 52 and the rear half area of the replacement area immediately before the defective sector and the first half area of the replacement area immediately after the defective sector are processed. If it is the latter half of the immediately preceding replacement area for the closest area of them, from the last replacement sector to the front,
If it is the first half area of the immediately following replacement area, the first replacement sector is searched backward for empty replacement sectors, and the process proceeds to step 53 to determine whether or not there are free replacement sectors, and to find a free replacement sector. If there is, go to step 60.

If it is determined in step 53 that there is no free replacement sector, the process proceeds to step 54, and the nearest area of the first half area of the replacement area immediately before the defective sector and the second half area of the replacement area immediately after is replaced. Then, if it is the first half area of the previous replacement area, from the last replacement sector to the front,
If it is the latter half of the replacement area immediately after, it searches forward for replacement sectors that are sequentially vacant from the last replacement sector, proceeds to step 55, determines whether or not there are replacement sectors, and determines whether replacement sectors are free. If there is, go to step 60.

If it is determined in step 55 that there are no spare replacement sectors, the process proceeds to step 56, in which the latter half of the spare area immediately before the spare area immediately before the defective sector and the rear area of the spare area immediately after the defective sector are located. For the closest one of the first half areas of the replacement area, if it is the second half area of the front replacement area, go forward from the last replacement sector, and if it is the first half area of the rear replacement area, start from the first replacement sector The vacant replacement sectors are sequentially searched backward, and the process proceeds to step 57 to determine whether or not the replacement sector is vacant. If there is a vacant replacement sector, the process proceeds to step 60.

If it is determined in step 57 that there is no free replacement sector, the process proceeds to step 58, in which the nearest area of the front half area of the front replacement area and the rear half area of the rear replacement area is If it is the front half area of the front spare area, the spare sector is searched forward from the last spare sector, and if it is the rear half of the rear spare area, the spare sector is searched sequentially from the last spare sector to the front, and a step 59 is searched.
If it is determined that there is no spare sector available, and there is no spare sector available, the process returns to step 56 and the search process is repeated for the front and rear areas. If there is, go to step 60. Then, in step 60, a spare process is performed on the spare sector that is vacant, and this process ends.

Next, the replacement process will be described in detail with reference to FIGS. 19 to 27. For example, FIG. 19B
As shown in FIG. 20, when a defect occurs in the sector c10 of the user area C, as shown in (b) of FIG. 20, the second half of the replacement area b immediately before the sector c10 and the first half of the replacement area c immediately after the sector c10. From the last replacement sector sb9 in the latter half of the replacement area b, which is the closest one of the areas, the replacement processing is performed by searching for replacement sectors that are sequentially vacant toward the front.

When all the replacement sectors sb5 to sb9 in the second half area of the replacement area b have been used, as shown in FIG. 21B, the first half of the replacement area c immediately after the sector c10. From the first replacement sector sc0 in the area, the replacement processing is performed by searching for replacement sectors sequentially vacant toward the rear.

Further, when all the replacement sectors sc0 to sc4 in the first half area of the replacement area c are also used, as shown in FIG. 22B, the first half of the replacement area b immediately before the sector c10. The spare sector is sequentially searched from the spare sector sb4 in the area toward the front, and spare processing is performed.

When all the replacement sectors sb0 to sb4 in the first half area of the replacement area c have also been used, as shown in FIG. 23B, the latter half of the replacement area c immediately after the sector c10. From the replacement sector sc5 in the area, the replacement processing is performed by searching for replacement sectors that are sequentially vacant toward the rear.

Further, the replacement area b immediately before the sector c10
When there is no vacant replacement sector in any of the replacement areas c immediately after the above, as shown in (b) of FIG. 24, the latter half area of the replacement area a further ahead of the sector c10 and the replacement area d behind it. From the last replacement sector sa9 of the second half area of the replacement area a, which is the closest one of the first half areas of the above, the replacement processing is performed by sequentially searching for replacement sectors that are vacant toward the front.

When all the replacement sectors sa5 to sa9 in the latter half area of the replacement area a are all used, as shown in (b) of FIG. 25, the first half area of the rear replacement area d From the first replacement sector sd0, a replacement process is performed by sequentially searching for replacement sectors that are vacant toward the rear.

Further, when there is no vacant replacement sector in both the second half area of the replacement area a and the first half area of the replacement area d, as shown in FIG. 26 (b), the replacement area a
Of the first half area and the second half area of the replacement area d, the replacement processing is performed by searching for replacement sectors sequentially vacant from the replacement sector sa4 in the first half area of the replacement area a, which is the closest one.

Then, when all the replacement sectors sa0 to sa4 in the first half area of the replacement area a are all used, as shown in FIG. 27B, the replacement sectors in the second half area of the replacement area d. From sd5, vacant replacement sectors are sequentially searched backward and replacement processing is performed.

Alternatively, when a defect occurs in the sector c28 of the user area C, first, the replacement area c which is the closest to the latter half area of the replacement area b immediately before the sector c28 and the first half area of the replacement area c immediately after the sector c28. From the first replacement sector sc0 in the first half area of the above, the replacement processing is performed by searching for replacement sectors sequentially vacant backward.

Further, when all the replacement sectors sc0 to sc4 in the first half area of the replacement area c have been used, the last replacement sector sb9 in the second half area of the replacement area b immediately before the sector c28 is sequentially opened forward. The replacement sector is searched for the existing replacement sector. Further, when all the replacement sectors sb5 to sb9 in the latter half area of the replacement area b have also been used, the replacement sectors sc5 in the latter half area of the replacement area c immediately after the sector c28 are sequentially vacant rearward. Search for a sector and perform replacement processing.

Further, when all the replacement sectors sc5 to sc9 in the latter half area of the replacement area c are all used, the replacement area sb4 in the first half area of the replacement area b immediately before the sector c28 is sequentially emptied forward. The replacement sector is searched for the existing replacement sector.

Further, the replacement area c immediately after the sector c28
When there is no vacant replacement sector in either of the replacement area b and the immediately preceding replacement area b, the replacement area which is the closest of the first half area of the replacement area d further behind the sector c28 and the latter half area of the front replacement area a. From the first replacement sector sd0 in the first half area of d, the replacement processing is performed by searching for replacement sectors sequentially vacant to the rear.

When all the replacement sectors sd0 to sd4 in the first half area of the replacement area d have been used, the last replacement sector s in the second half area of the front replacement area a.
A spare sector is sequentially searched from a9 toward the rear to perform a spare process.

Further, when there is no available spare sector in either the first half area of the replacement area d or the second half area of the replacement area a, the closest one of the second half area of the replacement area d and the first half area of the replacement area a. The spare area is sequentially searched from the spare sector sd5 in the second half of the spare area d toward the rear, and the spare processing is performed.

When all the replacement sectors sd5 to sd0 in the latter half area of the replacement area d have been used, the replacement sectors sa4 in the first half area of the replacement area a are sequentially replaced with the replacement sectors vacant toward the front. Search for and perform replacement processing.

In this way, the spare processing can be performed on the free spare sector closest to the defective sector, and the spare area around the spare area is used exclusively by the specific user area, and the other user areas are separated. It can be prevented as much as possible that only the spare area can be used.

The above-described replacement processing can be performed on a storage medium having primary and secondary replacement areas.

[0126]

As described above, according to the replacement processing method in the information storage device of the present invention, the replacement processing is performed on the free replacement sector closest to the defective sector generated on the storage medium. The seek time for accessing the replacement sector can be shortened.

[Brief description of drawings]

FIG. 1 is a flowchart showing a replacement process of the present invention.

FIG. 2 is a block diagram showing a configuration of an information storage device according to an embodiment of the present invention.

3 is an explanatory diagram showing an example of a format of a recording surface of the storage medium 1 of FIG.

FIG. 4 is an explanatory diagram when the replacement processing of the present invention is applied to the recording surface of the storage medium of FIG.

FIG. 5 is an explanatory view of the same.

FIG. 6 is also an explanatory diagram thereof.

FIG. 7 is an explanatory view of the same.

FIG. 8 is a flowchart showing another replacement process of the present invention.

FIG. 9 is a flowchart showing still another replacement process of the present invention.

FIG. 10 is an explanatory diagram when the replacement process of the present invention is applied to the recording surface of the format of FIG.

FIG. 11 is an explanatory view of the same.

FIG. 12 is also an explanatory diagram thereof.

FIG. 13 is an explanatory diagram of the same.

FIG. 14 is also an explanatory diagram thereof.

FIG. 15 is an explanatory view of the same.

FIG. 16 is a flowchart showing still another replacement process of the present invention.

FIG. 17 is a flowchart showing still another replacement process of the present invention.

18 is an explanatory diagram showing an example of another format of the recording surface of the storage medium 1 of FIG.

FIG. 19 is an explanatory diagram when the replacement process of the present invention is applied to the recording surface of the format of FIG.

FIG. 20 is an explanatory diagram of the same.

FIG. 21 is also an explanatory diagram thereof.

FIG. 22 is an explanatory diagram of the same.

FIG. 23 is also an explanatory diagram thereof.

FIG. 24 is also an explanatory diagram thereof.

FIG. 25 is also an explanatory diagram thereof.

FIG. 26 is also an explanatory diagram thereof.

FIG. 27 is also an explanatory view of the same.

FIG. 28 is a flow chart showing still another replacement process of the present invention.

FIG. 29 is a flowchart showing a conventional replacement process.

[Explanation of symbols]

 1: Information storage device 2: Storage medium 3: Read / write control unit 4: CPU 5: Program ROM 6: RAM 7: Interface (I / F) 10: Recording surface of storage medium

Claims (6)

[Claims] 1. A storage medium provided with a plurality of groups each having a user area including a plurality of sectors into which data is written by a user and a replacement area including a plurality of replacement sectors for replacement processing with respect to a defective sector of the user area. Writing means for writing data, reading means for reading data stored in the storage medium, and when a defective sector in which data cannot be written by the writing means occurs in the user area, the replacement area In an information storage device having a replacement processing means for carrying out a replacement process for writing data to a vacant replacement sector, the replacement process is carried out to a vacant replacement sector in a replacement area closest to the defective sector that has occurred. Replacement processing method. 2. A storage medium having a plurality of groups each having a user area including a plurality of sectors to which data is written by a user and a replacement area including a plurality of replacement sectors for replacement processing for a defective sector in the user area. Writing means for writing data, reading means for reading the data stored in the storage medium, and when a defective sector in which data cannot be written by the writing means occurs in the user area, the replacement area In an information storage device provided with a replacement processing means for performing a replacement process of writing data to a vacant replacement sector, when all replacement sectors in the replacement area of the group to which the generated defective sector belongs have been used, Replacement characterized by performing replacement processing on an empty replacement sector in a replacement area of another group closest to the sector Management method. 3. The replacement processing method according to claim 2, wherein when all the replacement sectors in the replacement area of the group immediately before and after the group to which the generated defective sector belongs are already used, A replacement processing method, characterized in that replacement processing is performed on a free replacement sector in a replacement area of a group closest to a front or rear group. 4. A storage medium having a plurality of groups each having a user area including a plurality of sectors to which data is written by a user and a replacement area including a plurality of replacement sectors for replacement processing for a defective sector in the user area. Writing means for writing data, reading means for reading data stored in the storage medium, and when a defective sector in which data cannot be written by the writing means occurs in the user area, the replacement area In an information storage device provided with a replacement processing means for carrying out a replacement process for writing data to an empty replacement sector, each replacement area is divided into a first half area and a second half area so that the number of replacement sectors is halved. , The empty area of the closest one of the second half area of the replacement area immediately before the defective sector and the first half area of the replacement area immediately after When the sector is subjected to the replacement process and there is no free replacement sector in any of the areas, the nearest area of the first half area of the immediately preceding replacement area and the second half area of the immediately following replacement area is empty. A replacement processing method, wherein replacement processing is performed on a replacement sector. 5. The replacement processing method according to claim 4, wherein when there is no available replacement sector in either of the replacement areas immediately before and immediately after the defective sector that has occurred, the second half area and the rear area of the replacement area further ahead. Of the spare area of the first half area of the replacement area is subjected to the spare processing in the nearest spare area, when there is no spare sector in any of the areas, the first half area of the preceding spare area and A replacement processing method, wherein replacement processing is performed on an empty replacement sector in the closest one of the rear half areas of the rear replacement area. 6. The replacement processing method according to claim 1, wherein a spare area in front of the defective sector in which the defective sector has occurred is vacant in sequence from the last spare sector in the spare area. A replacement processing method, wherein a replacement sector is searched for, and in the replacement region in the rear, a replacement sector sequentially vacant from the first replacement sector in the replacement region toward the rear is searched.