JPH07325669A - Disk controlling method - Google Patents

Abstract

PURPOSE:To improve file access performance by referring to a continuous nonuse block list, selecting the list entry of a minimum number of block from the list entry of the number of block which is more than the number of block required for a writing and assigning the corresponded continuous nonuse block. CONSTITUTION:A disk block control part 100 prepares a continuous nonuse block list 110 from a bit map 220 at the time of starting the use of the disk 200. Whether the disk use is terminated or not is decided. When the disk use is not terminated, whether a block operation exists or not is inspected. When a block request exists, whether nonuse blocks exist sufficiently and files are possible to be assigned to the nonuse blocks or not are decided. If the assignment is possible, the disk blocks are assigned. If the nonuse blocks do not exist sufficiently and an assignment impossible is decided, the state is returned to a disk use termination inspection. At this stage, the bit map 200 records the use status of the disk 200.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk management method such as a floppy disk, a hard disk, a magneto-optical disk which is used in an information processing system and which can be randomly accessed. The present invention relates to a disk management method capable of efficiently utilizing a storage medium by further improving the efficiency of the disk and preventing fragmentation of the disk.

[0002]

2. Description of the Related Art In a conventional OS, disk blocks allocated to files are generally arranged randomly.
A large amount of head seeks occurred in the file access, which slowed down the access speed.

FIG. 17 is a diagram showing a disk area structure in a "data storage method" as a conventional disk management method disclosed in Japanese Patent Laid-Open No. 4-77938, for example.
In the figure, 900 is a disk and 910 is a disk 90.
0 is a directory area, 920 is an index area of the disk 900, 930 is a bitmap area of the disk 900, and 940 is a data area of the disk 900. The disk 900 is divided into these areas, and the bitmap area 930 has a data area. The disk block usage status of 940 is recorded. FIG. 18 is a diagram showing the structure of a bitmap and an unused area list used in the conventional disk management method. In the figure, 950 is an unused area list and 951 is a series of continuous unused blocks. The start address where the area starts, and 952 is the size of several consecutive blocks.

Next, the operation will be described. The system creates an unused area list 950 from the information in the bitmap area 930 when starting to use the disk 900. In the unused area list 950, a start address 951 at which a continuous area starts when the unused blocks in the disk are continuous, and a number of continuous block sizes 952 are recorded. These are in the order of the block size. It is recorded. When allocating a disk block to a file, a block is allocated from the head entry of an unused continuous block having the largest block size 952 in the unused area list 950. Then, if the contiguous block alone is insufficient to write the file, the next unused block is allocated.

[0005]

In the conventional disk management method, physically scattered blocks are allocated to the file, and there is a problem that the access speed is reduced when accessing the file.

Further, the disk management method disclosed in Japanese Patent Laid-Open No. 4-77938 aims at allocating consecutive blocks to a file to improve access performance, prevent fragmentation of the disk, and use the file efficiently. However, there is a problem that fragmentation cannot be completely prevented in order to use the largest continuous free area.

The invention of claim 1 is to solve the above problems, and an object thereof is to provide a disk management method capable of improving file access performance and preventing fragmentation of a storage medium. And

It is an object of the present invention to provide a disk management method capable of reducing the amount of head seek during file access and speeding up file access.

An object of the present invention is to provide a disk management method capable of reliably and easily providing a continuous file when a block requires a physically continuous file (continuous file). To do.

An object of the present invention is to provide a disk management method capable of further increasing the effect of avoiding fragmentation of a storage medium by avoiding useless consumption of a continuous unused block list.

It is an object of the invention of claim 5 to provide a disk management method in which a continuous unused block list always reflects the usage status of a storage medium.

[0012]

A disk management method according to the invention of claim 1 refers to a continuous unused block list, and selects from among list entries having a number of blocks equal to or greater than the number of blocks required for writing a file. The list entry having the minimum number of blocks is selected, and consecutive unused blocks corresponding to the list entry are allocated for the file.

In the disk management method according to the second aspect of the present invention, when allocating blocks to the existing file in the storage medium, the continuous unused block list is referred to and a block adjacent to the block including the end of the file is provided. Consecutive unused blocks corresponding to list entries are assigned with priority.

In the disk management method according to the third aspect of the present invention, when continuous blocks are requested when writing a file, if the number of blocks required for writing the file is larger than the maximum number of blocks of the list entry. , Blocks cannot be allocated, and allocation of physically consecutive blocks is guaranteed.

According to another aspect of the disk management method of the present invention, if the number of blocks required to write a file is smaller than the minimum number of blocks in the list entry of the continuous unused block list, the bitmap is searched and the continuous unused blocks are searched. A block that is not included in the used block list is allocated.

The disk management method according to the invention of claim 5 is not used for allocation in a released block when a block is released from a file and in a list entry used for allocation when a block is assigned to a file. A new list entry recorded in the continuous unused block list is created from the block.

[0017]

According to the disk management method of the present invention,
With reference to the continuous unused block list, select the list entry with the minimum number of blocks from the list entries with the number of blocks equal to or greater than the number of blocks required to write the file, and select the continuous unused block corresponding to the list entry. Allocate for a file. As a result, an unused block having an optimal size larger than the file size can be allocated to the file, and the blocks can be allocated as consecutive blocks as possible. Therefore, the access to the file can be speeded up, the fragmentation of the disk can be avoided, and the disk can be efficiently used.

According to a second aspect of the present invention, the disk management method refers to a continuous unused block list and corresponds to a list entry having a block adjacent to a block including the end of the file in the case of expanding an existing file. Prioritize allocation of consecutive unused blocks. As a result, the amount of head seek in file access is reduced, and file access can be speeded up.

In the disk management method according to the third aspect of the present invention, when continuous blocks are requested when writing a file, if the number of blocks required to write the file is larger than the maximum number of blocks of the list entry, Blocks cannot be allocated. This makes it possible to reliably and easily provide a continuous file when a block requires a physically continuous file (continuous file).

According to a fourth aspect of the present invention, in the disk management method, when the number of blocks required for writing a file is smaller than the minimum number of blocks in the list entry of the continuous unused block list, the bitmap is searched and the continuous unused block is searched. Allocate blocks that are not included in the block list. As a result, useless consumption of the continuous unused block list can be avoided, and the effect of avoiding fragmentation of the disk can be improved.

The disk management method according to the invention of claim 5 is not used for allocation in the released block when the block is released from the file and the list entry used for allocation when the block is assigned to the file. Create a new list entry from the block to be recorded in the contiguous unused block list. In this way, management of the continuous unused block list at the time of disk block allocation and release can be strengthened, and the continuous unused block list can always reflect the usage status of the disk.

[0022]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. 1 is a block diagram for explaining a disk management method according to an embodiment of the present invention. In FIG. 1, 100 is a disk block management unit, and 200 is a disk managed by the disk block management unit 100 ( A storage medium) 220 is a bitmap 220 recording the usage status of the disk 200. 110 is a continuous unused block list, and 150 is a bitmap. The bitmap 150 is the bitmap 2 existing on the disc 200.
20 copies, and is provided in the disk block management unit 100 as a cache, for example, in order to speed up access. Basically, the bitmap 150 may be considered the same as the bitmap 220 existing on the disc 100.

FIG. 2 is a diagram showing the structure of a disk 200 to which the disk management method according to this embodiment is applied. In the figure, 201 is a block. The block 201 is a minimum unit for recording data, and its block length is fixed. One or more blocks 20 in one file
1 is assigned and data can be recorded. 202
Is a block number, and all blocks are sequentially numbered from 1 from the beginning of the disk 200 in block units.
In the example shown, the disk 200 has 32 disk blocks with block numbers 1 to 32. The disk block management unit 100 has a block number of 20.
2 manages the block 201.

FIG. 3 is a diagram showing an area structure of a disk 200 to which the disk management method according to this embodiment is applied. In the figure, 210 is a disk management area. The disk management area 210 is an area for recording information for managing the disk 200 such as the number of blocks of the disk 200. Reference numeral 220 is a bitmap, which records the usage status of blocks. Reference numeral 230 denotes a file management area, which is an area for recording information regarding files. A data area 240 is an area for recording the contents of the file. Not limited to this embodiment, the disk management method according to the present invention does not depend on the structures of the disk management area 210 and the file management area 230, so detailed description of the structure will be omitted.

Next, the structure of the bitmap 220 will be described. FIG. 4 is a diagram showing the structure of a bitmap 220 used for the disc management method according to this embodiment, in which 221 is a bit. One bit 221 represents the usage status of one block 201. If the bit 221 is "0", it can be assigned to a file without being used, and if it is "1", it means that it is used for an arbitrary file and cannot be assigned. The first bit of the bitmap 220 is the block 2 with the block number 1.
The usage status of 01 is recorded. Hereafter, successive bits are the block numbers 202 corresponding to the bit positions in order.
The usage status of the block 201 having The bitmap 220 is updated in real time when the block 201 is allocated and released, and always records the latest usage status of the block 201.

Next, the structure of the continuous unused block list 110 of the disk block management unit 100 will be described.
FIG. 5 is a diagram showing the structure of the continuous unused block list 110 used in the disk management method according to this embodiment.
In the figure, 111 is a continuous unused block list entry. The continuous unused block list entry 111 records a continuous start block number 112 and a continuous size 113. The continuation start block number 112 is the head block 201 when there are consecutive unused blocks.
Block number 202, and the continuous size 113 is the number of continuous unused blocks. Reference numeral 115 is an unused entry that is not currently used. Reference numeral 130 denotes a continuous size order list, and the continuous unused block list entries 111 are arranged on the continuous size order list 130 in descending order of the continuous size 113. 131 is the first entry of the continuous size order list 130, and 132 is the last entry. Reference numeral 140 is an entry search pointer, which is used in the allocation process as described later in block 201.

Next, the operation will be described. FIG. 6 is a flow chart showing the outline of the disk block management processing by the disk management method according to this embodiment. First, in step ST500, the disk block management unit 1
00 is a bitmap 22 when the use of the disc 200 is started.
A continuous unused block list 110 is created from 0. It is determined whether or not the disk has been used (step ST51
0) If the disk is not used up, it is checked whether or not there is a block operation (step ST520). When there is a block request, it is determined whether there are enough unused blocks and the file can be allocated to the unused blocks (step ST530), and if the allocation is possible, disk block allocation is performed (step ST60).
0) If it is determined in step ST530 that there are not enough unused blocks and allocation is impossible, the process returns to the disk use end inspection (step ST510).

On the other hand, if there is a block release request, the process proceeds from step ST520 to step ST700 to release the disk block. After the block operation, it is checked whether or not the condition for recreating the continuous unused block list 110 is reached (step ST540), and if it is reached, the process returns to the continuous unused block list creation (step ST500), and if not reached, the disk is used. The procedure returns to the end inspection (step ST510). Disk block management unit 100
Repeats this operation until the use of the disk 200 is completed.

As described above, the processing of the disk management method according to this embodiment includes the continuous unused block list creation (step ST500), disk block allocation (step ST600), and disk block release (step ST700) shown in FIG. Divided into three. Each processing will be described in detail below. Further, for details of the conditions for recreating the continuous unused block list 110, create a continuous unused block list (step ST500).
In the explanation of.

Next, the process of creating a continuous unused block list will be described. FIG. 7 is a flow chart illustrating the operation of the disk block management unit 100 to which the disk management method according to this embodiment is applied to create the continuous unused block list 110.

As shown in FIG. 7, the disk block management unit 100 first creates a continuous size order list 130 as shown in FIG. 5 from the information of the bitmap 220 (step ST501). The disk block management unit 100 thereafter uses this continuous unused block list 110,
Perform block allocation processing.

Next, the continuous unused block list re-creation condition used in step ST540 of FIG. 6 will be described.
The continuous unused block list 110 is created at the start of use of the disk 200, but the continuous unused block list 11 is created by disk block allocation and disk block release.
0 may not completely reflect the continuous state of unused blocks. The reason why this happens will be described later.

There are the following two conditions for recreating the continuous unused block list 110.

(1) With respect to the number of unused blocks existing on the disk 200, the total of the continuous sizes 113 of all the continuous unused block list entries 111 becomes smaller than a specified value or a specified ratio.

(2) The number of unused entries 115 is larger than the specified value or the specified ratio with respect to the number of continuous unused block list entries 111 existing in the disk block management unit 100.

When both of these two conditions are satisfied while the disk 200 is in use, there is a difference between the status of the actual unused block and the status of the continuous unused block list 110, and the continuous unused block list 110. Is re-created, the continuous unused block list 110 is re-created from the bitmap 220.

Next, the disk block allocation process will be described. FIG. 8 is a flow chart for explaining the operation of the disk block management unit 100 for allocating blocks in the disk management method according to this embodiment. When the disk block management unit 100 allocates blocks, the disk block management unit 100 shown in FIG.
The continuous size order list 130 shown in (1) is searched and the block is allocated to the file from the entry 111 having the optimum size.

First, in the continuous unused block list 110, the entry search pointer 140 pointing to the entry 111 currently being investigated is set to the continuous size ordered list end entry 132.
Is set (step ST611). Last entry 13
2 has the smallest continuous size 113 in the continuous unused block list 110. The disk block management unit 100 uses the continuous size 1 of the entry pointed to by the entry search pointer 140.
13 and the requested size are compared (step ST620).
If the requested size is larger, the entry search pointer 1
It is inspected whether 40 indicates the top entry 131 of the continuous size order list (step ST630). If the entry is not the first entry 131, there is an entry having a larger continuous size 113, so the entry search pointer 140
In the continuous size-ordered list 130, the next higher entry 11
It is set to 1 (step ST631).

When the search is advanced and an entry 111 whose continuous size 113 is larger than the required size is found (step S
(T620), a block of the requested size is allocated to the file from the entry 111 pointed to by the entry search pointer 140 (step ST651). Next, the entry 111 for which a block is allocated for this file is removed from the continuous unused block list 110 and cleared (step ST671). Also, the allocated block is reflected in the bitmap 220 (step ST676). At this time, the blocks not included in the entry 111 used for allocation but not allocated are also in the continuous unused block list 11
It will be removed from 0. Therefore, there may be a difference between the continuous status of unused blocks and the information of the continuous unused block list.

On the other hand, in step ST630, the entry search pointer 140 is set to the continuous size order list head entry 131 while the entry 111 used for allocation is searched.
When it reaches, since there is no entry 111 having a larger continuous size 113, all blocks are allocated to the file from the head entry 131, and the used entry 111 is removed from the continuous unused block list 110 (step ST636). Next, the size obtained by subtracting only the size of the allocated block from the request size is set as the request size for the next search (step ST637). Then, it is checked whether or not the requested size is zero (step ST640), and if the requested size is not zero, the process returns to step ST611 and the search and allocation are repeated from the beginning, and the file is blocked until the requested size becomes zero. Assign

In step ST640, if it becomes clear that the requested size becomes zero and the allocation of the file is completed, the process moves to step ST671 and the block for this file is used for allocation. 111 is removed from the continuous unused block list 110 and cleared, and the allocated block is bitmap 22
It is reflected in 0 (step ST676). At this time, the blocks included in the entry 111 used for allocation but not allocated are also removed from the continuous unused block list 110. Therefore, there may be a difference between the continuous status of unused blocks and the information of the continuous unused block list.

Next, the block release processing will be described.
FIG. 9 is a flow chart for explaining the operation of the disk block management unit 100 releasing a block in the disk management method according to this embodiment. When the disk block in the disk is released, it is first checked whether or not the released block to be released can newly create the entry 111 shown in FIG. 5 (step ST730). If the released blocks are continuous, the continuous size is larger than the continuous size 113 of the continuous size order list end entry 132 shown in FIG. 5, and the disk block management unit 100 has an unused entry 111, a new entry 111 is created. Since it can be created, the entry 111 is created from the released block and inserted into the continuous unused block list 110 (step ST731). Also, the released block is reflected in the bitmap 220 (step ST732). In this way, since it is checked whether or not the entry 111 can be created only from the released block and the entry is created by this, a difference may occur between the continuous status of the unused blocks and the information of the continuous unused block list 110. .

As described above, according to this embodiment, it is possible to obtain the block management method capable of improving the file access performance and preventing the fragmentation of the disk.

Example 2. Next, a disk management method according to an embodiment of the present invention will be described. The system block diagram and various data structures of this embodiment are the same as those of the first embodiment except the continuous unused block list 110 and the disk block allocation process. Therefore, the description of the same points is omitted.

First, the structure of the continuous unused block list used by the disk management method according to this embodiment will be described with reference to the drawings. FIG. 10 is a view showing the structure of the continuous unused block list 110 used in the disk management method according to the embodiment of the invention of claim 2, and 111 is a continuous unused block list entry. The continuous unused block list entry 111 records a continuous start block number 112 and a continuous size 113. Continuous start block number 11
2 is the block number 202 of the first block 201 when there are consecutive unused blocks, and the continuous size 113 is the number of consecutive unused blocks. 115
Is an unused entry that is not currently used.

The continuous unused block list 110 includes two lists, a block number ordered list 120 and a continuous size ordered list 130. Although these two lists each have a plurality of entries, they do not have different independent entries 111, but the two lists have the same entry 111 respectively. Figure 10
In the left, the block number order list 120 on the left side is sorted in the order of continuous start block numbers 112, and the continuous size order list 130 on the right side is sorted in the order of continuous sizes 113. In the figure, 121 is the head entry of the block number order list 120, and 122 is the tail entry. 131 is the first entry of the continuous size order list 130, and 132 is the last entry. An entry search pointer 140 is used in the allocation process of the block 201.

The processing outline of the disk management method of this embodiment is almost the same as that of FIG. 7 of the first embodiment, but the processing of the continuous unused block list creation (step ST500) and disk block allocation (step ST600) is performed. Different from the first embodiment. Hereinafter, this different part will be described in detail.

First, the process of creating a continuous unused block list will be described. FIG. 11 is a flow chart for explaining the operation of the disk block management unit 100 creating the continuous unused block list 110 in the disk management method according to this embodiment. Disk block management unit 1
00 creates the continuous size order list 130 from the information of the bitmap 220 (step ST501), and further creates the block number order list 120 using the same entry (step ST502). The disk block management unit 100 thereafter uses the continuous unused block list 110 including the block number ordered list 120 and the continuous size ordered list 130 to perform block allocation processing.

FIG. 12 is a flow chart showing the operation of allocating blocks by the disk block management unit 100 in this embodiment, which will be described below with reference to this figure.
This embodiment differs from the first embodiment in the operation of setting the entry search pointer 140 depending on whether the block request source file is an existing file or a new file. The disk block management unit 100 checks whether the request source is an existing file (step ST610), and if it is an existing file, the entry search pointer 140 is set to the block existing in the end of the request source file from the block number ordered list 120. The entry 111 having the smallest continuous start block number 112 beyond the block number is searched, and the entry search pointer 140 is set to the entry 111 (step ST616). On the other hand, when the request source is a new file, the entry search pointer 1 as in the first embodiment.
40 is set to the continuous size list end entry 132 (step ST611). Due to the difference in the setting of the entry search pointer 140, the entry search pointer 14
When the entry 111 in which 0 is set has a sufficient size, it is possible to allocate a block adjacent to the file end block to the existing file. Since the subsequent operation, that is, the processing of steps ST620 to ST676 is the same as the disk block allocation processing of the first embodiment shown in FIG. 8, the description thereof is omitted.

As described above, according to this embodiment, it is possible to obtain a block management method capable of reducing the amount of head seek during file access and speeding up file access.

Example 3. Next, a disk management method according to an embodiment of the present invention will be described. The system block diagram and various data structures of this embodiment are the same as those of the first embodiment except the disk block allocation process. Therefore,
Description of similar points is omitted. The different parts will be described in detail below.

FIG. 13 is a flow chart for explaining the operation of the disk block management unit 100 for allocating blocks in the disk management method according to this embodiment. In this embodiment, the operation when the entry search pointer 140 reaches the head entry 131 (step ST630) during the search of the entry 111 is different from that of the first embodiment shown in FIG.

The disk block management unit 100 is the first embodiment.
Similarly, the entry search pointer 140 is set to the continuous size list end entry 132 (step ST61).
1) The entry 111 having the required size is searched (step ST620). When the entry search pointer 140 reaches the top entry 131 during the process (step ST
630), and it is checked whether a continuous block is requested (step ST635). If continuous blocks are not requested, the process proceeds to step ST636 which is similar to the disk block allocation process of the first embodiment, and then the same process is executed. When a continuous block is requested, there is no continuous block beyond the continuous size order list top entry 131, so continuous block allocation is not possible and the processing is interrupted (step ST6).
38), transition to step ST671 and entry 111 for which the block was used for allocation for this file.
Clear from the continuous unused block list 110,
The allocated block is reflected on the bitmap 220 (step ST676). At this time, the blocks included in the entry 111 used for allocation but not allocated are also removed from the continuous unused block list 110. In this way the allocation of consecutive blocks is guaranteed.

As described above, according to this embodiment, a block management method capable of reliably and easily providing a continuous file when a block physically needs a continuous file (continuous file). Obtainable.

Example 4. Next, a disk management method according to an embodiment of the present invention will be described. The system block diagram and various data structures of this embodiment are the same as those of the first embodiment except the continuous unused block list creation process and the disk block allocation process. Therefore, the description of the same points is omitted.

The processing outline of the disk management method of this embodiment is almost the same as that of FIG. 7 of the first embodiment, but the continuous unused block list preparation (step ST500) and the disk block allocation processing (step ST600) are carried out in the first embodiment. Different from the continuous unused block list creation process (step S
T500) is the same as in Example 2. The parts different from the first and second embodiments will be described in detail below.

FIG. 14 is a flow chart for explaining the operation of the disk block management unit 100 for allocating blocks in the disk management method according to this embodiment. In this embodiment, the operation is different from that of the first embodiment shown in FIG. 8 when the requested size is smaller than the continuous size 113 of the continuous size ordered list end entry 132.

The disk block management unit 100 is the first embodiment.
Similarly, the entry search pointer 140 is set to the continuous size list end entry 132 (step ST61).
1) The entry 111 having the required size is searched (step ST620). When an entry 111 having a continuous size 113 equal to or larger than the requested size is found in the entry search having the required size, it is checked whether or not the entry search pointer 140 points to the continuous size ordered list end entry 132 (step ST650). End entry 132
If the unused block is not included in the continuous unused block list 110, it is checked whether or not there is an unused block having a block size equal to or larger than the requested size (step ST660). If such an unused block exists,
The bitmap 220 and the block number order list 120 are examined without allocating the blocks of the continuous unused block list entry 111, and unused blocks not included in the continuous unused block list 110 are allocated to the file (step ST661).

On the other hand, when the entry search pointer 140 does not point to the tail entry 132, or when it points to the tail entry 132, the continuous unused block list 11
If there are not enough unused blocks that are not included in 0, a block is allocated from the entry 111 pointed to by the entry search pointer 140 as in the first embodiment. The other processing is the same as the disk block allocation processing shown in FIG. 8 in the first embodiment, and therefore its explanation is omitted.

As described above, it is possible to obtain a block management method capable of further increasing the effect of avoiding disk fragmentation by avoiding useless consumption of the continuous unused block list.

Example 5. Next, a disk management method according to an embodiment of the present invention will be described. The system block diagram and various data structures of this embodiment are the same as those of the first embodiment except for the continuous unused block list creation processing, disk block allocation processing, and disk block release processing. Therefore, the description of the same points is omitted.

The processing outline of the disk management method according to this embodiment is the same as that of the first embodiment shown in FIG. 7, in which the continuous unused block list creation processing (step ST50) is performed.
0), disk block allocation processing (step ST60)
0), disk block release processing (step ST70)
0) is different from the first embodiment, the continuous unused block list creation process (step ST500) is the same as the second embodiment. Hereinafter, the parts different from the first and second embodiments will be described in detail.

FIG. 15 is a flow chart for explaining the operation of the disk block management unit 100 for allocating blocks in the disk management method according to this embodiment. In this embodiment, the operation of the entry 111 after allocating a block from the entry 111 to a file is different from that of the first embodiment. As in the first embodiment, the disk block management unit 100 sets the entry search pointer 140 to the continuous size order list end entry 132 (step ST611) and searches for the entry 111 having the requested size (step ST).
620). When an entry 111 having a continuous size 113 equal to or larger than the requested size is found in the entry search having the requested size, the requested size is allocated to the file (step ST651), the entry 111 used for allocation is removed from the continuous unused block list 110, and cleared. Yes (step ST671). Next, if the entry 111 included in the entry 111 used for the allocation can be created from the remaining block that is not allocated to the file,
An entry 111 is newly created in the block and inserted into the continuous unused block list 110 (step ST6).
72). Then, the last allocated block is reflected in the bitmap 220 (step ST676). The other processing is the same as the disk block allocation processing according to the first embodiment shown in FIG.

FIG. 16 is a flow chart for explaining the operation of releasing the block by the disk block management unit 100 in this embodiment. This embodiment differs from the first embodiment in the inspection as to whether the entry 111 can be created by the release block. In releasing a block, it is first checked from the block number ordered list 120 whether or not a new entry 111 can be created from the released block and the blocks already included in the continuous unused block list 110 (step S).
T710). When the release block and the block included in the existing entry 111 are physically continuous blocks, the release block can be included in the entry 111 to form a new entry 111. If it can be created, the existing entry 111 is added to the continuous unused block list 110.
, A new entry 111 is created from the block included in the existing entry 111 and the released block, and is inserted into the continuous unused block list 110 (step ST
711).

Next, in step ST710, when it is revealed that a new entry cannot be created from the released block and the block included in the existing entry 111, the released block and the unused block not included in the continuous unused block list 110. Is checked from the bitmap 150 and the block number ordered list 120 whether or not the new entry 111 can be created (step ST720).
When a free block and an unused block that is not included in the continuous unused block list 110 are physically continuous and the continuous size is larger than the continuous size ordered list end entry 132 and the unused entry 115 exists, a new entry is created. 111 can be created. If it can be created, a new entry 111 is created and the continuous unused block list 1
10 is inserted (step ST721). On the other hand, if it is found in step ST720 that a new entry cannot be created from the released block and an unused block not included in the list, it is checked whether an entry can be created from only the released block as in the first embodiment (step). S
T730). If it can be created, a new entry 111 is created from the released block, and the continuous unused block list 110 is created.
(Step ST731). The last released block is reflected in the bitmap 220 (step S
T732).

As described above, it is possible to obtain the disk management method in which the continuous unused block list can always reflect the usage status of the storage medium, and the continuous unused block list management is strengthened.

[0067]

As described above, according to the first aspect of the present invention, the smallest block is selected from the list entries having the number of blocks equal to or more than the number of blocks required for writing the file by referring to the continuous unused block list. Since we have selected a number of list entries and configured to allocate contiguous unused blocks for the file for the file,
It is possible to allocate consecutive blocks to the file as much as possible, speed up access to the file, avoid fragmentation of the storage medium, and use the storage medium efficiently.

According to the second aspect of the invention, in the case of expanding an existing file, the continuous unused block list is referred to, and the continuous unused block list corresponding to the list entry having a block adjacent to the block including the end of the file is referred to. Since it is configured to allocate used blocks with priority, the amount of head seek is reduced when accessing files,
There is an effect that file access can be performed at high speed.

According to the third aspect of the present invention, when consecutive blocks are requested when writing the file, if the number of blocks required for writing the file is larger than the maximum number of blocks of the list entry, block allocation is performed. I configured it to be impossible, so if a block requires a physically contiguous file (contiguous file),
There is an effect that a continuous file can be provided reliably and easily.

According to the fourth aspect of the invention, when the number of blocks required to write the file is smaller than the minimum number of blocks in the list entry of the continuous unused block list, the bitmap is searched and the continuous unused block list is searched. Since it was configured to allocate blocks not included in
There is an effect that wasteful consumption of the continuous unused block list can be avoided, and further fragmentation avoidance of the storage medium can be improved.

According to the fifth aspect of the invention, the blocks released when the blocks are released from the file and the blocks not used for the assignment in the list entry used for the assignment when the blocks are assigned to the file Since it is configured to create a new list entry recorded in the continuous unused block list, the management of the continuous unused block list at the time of allocating and releasing the storage medium block is strengthened, and the continuous unused block list is always stored. There is an effect that can reflect the usage status of the medium.

[Brief description of drawings]

FIG. 1 is a system block diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing the structure of a disc used in an embodiment of the present invention.

FIG. 3 is a diagram showing an area structure of a disc used in an embodiment of the present invention.

FIG. 4 is a diagram showing a structure of a bitmap used in an embodiment of the present invention.

FIG. 5 is a diagram showing a structure of a continuous unused block list used in one embodiment of the inventions of claims 1 and 3;

FIG. 6 is a flowchart showing a disk management process according to an embodiment of the present invention.

FIG. 7 is a flowchart for explaining a process of creating a continuous unused block list according to an embodiment of the inventions of claims 1 and 3;

FIG. 8 is a flowchart for explaining a disk block allocation process showing an embodiment of the invention of claim 1;

FIG. 9 is a flowchart for explaining a disk block releasing process according to an embodiment of the invention of claim 1;

FIG. 10 is a diagram showing a structure of a continuous unused block list used in an embodiment of the inventions of claims 2, 4 and 5;

FIG. 11 is a flowchart for explaining a continuous unused block list creation process according to an embodiment of the inventions of claims 2, 4 and 5;

FIG. 12 is a flow chart for explaining a disk block allocation process according to an embodiment of the invention of claim 2;

FIG. 13 is a flow chart for explaining a disk block allocation process according to an embodiment of the invention of claim 3;

FIG. 14 is a flowchart for explaining a disk block allocation process according to an embodiment of the invention of claim 4;

FIG. 15 is a flow chart for explaining a disk block allocation process according to an embodiment of the invention of claim 5;

FIG. 16 is a flowchart for explaining a disk block releasing process according to an embodiment of the invention of claim 5;

FIG. 17 is a diagram showing a disk area configuration used in an example of a conventional disk management method.

FIG. 18 is a diagram showing configurations of a bitmap and an unused area list used in an example of a conventional disk management method.

[Explanation of symbols]

110 continuous unused block list, 111 continuous unused block list entry (list entry), 15
0, 220 bitmap, 200 disk (storage medium), 201 blocks.

Claims (5)

[Claims] 1. A disk management method for writing a file in fixed-length block units, wherein a bitmap for recording whether each block is already used or unused is provided on the storage medium, and Before writing an arbitrary file to the storage medium, referring to the bitmap, a list entry of information indicating the number of blocks of a portion where unused blocks are continuously present and the position of the portion on the storage medium is entered. Create a continuous unused block list to record as, and refer to the continuous unused block list, and select the list entry of the minimum block number from the list entries of the block number equal to or more than the number of blocks required for writing the file. Characterized by selecting and allocating consecutive unused blocks corresponding to said list entry for said file Disk management method for storage media. 2. When allocating blocks to an existing file on the storage medium, the continuous unused block list is referred to, and a continuous unused corresponding to a list entry having a block adjacent to a block including the end of the file. The block is preferentially assigned, and the block is assigned.
Disk management method described in. 3. When writing a file, when consecutive blocks are requested, if the number of blocks required for writing the file is larger than the maximum number of blocks of a list entry, it is determined that the block cannot be allocated and physical allocation is performed. The disk management method according to claim 1 or 2, wherein the allocation of consecutive blocks is guaranteed. 4. If the number of blocks required to write a file is smaller than the minimum number of blocks in a list entry of the continuous unused block list, the bitmap is searched and is not included in the continuous unused block list. The disk management method according to any one of claims 1 to 3, wherein blocks are allocated. 5. A block that is released when a block is released from a file and a block that is not used for assignment in a list entry used when assigning a block to a file is added to the continuous unused block list. The disk management method according to any one of claims 1 to 4, wherein a new list entry to be recorded is created.