KR20090033623A - File system and method for using the file system - Google Patents

Abstract

A file system and a method for using the file system are provided to reduce the number of accesses to a storage device, thereby shortening time for a file processing command. A cluster area(120) comprises N clusters. N is a natural number. A cluster reference area(110) comprises information about whether to use the clusters. Each cluster comprises header areas(120-0~120-(N-1)). The header area stores information about connected clusters. The cluster reference area comprises a hash data area for finding a cluster having a specific value. A hash data area comprises a cluster bank area and a cluster ready group area for using a task scheduling technique of a UC/OS-II.

Description

File system and method for using the file system

The present invention relates to a file system, and more particularly, to a file system capable of ensuring a constant responsiveness of reading and / or writing in a mobile device or the like.

The biggest feature of recent mobile devices is the expansion of multimedia functions.

While existing mobile devices mainly add / modify data into database files such as notepad, notepad, address book, calendar, etc., mobile devices that perform multimedia functions play large video, still and music files. It mainly performs a task of downloading or uploading data, or generating data or communicating with a personal computer (PC) through wired / wireless communication.

As multimedia functions become the main functions of mobile devices, the importance of data storage and management functions is increasing.

Data storage and management functions, ie writing and reading functions, are performed by the file system.

1 is a schematic diagram illustrating a general file system.

Referring to FIG. 1, the file system receives a file processing command (eg, a write, read, or delete) output from an application program, and stores an operation corresponding to the received command through a device driver. (storage). For example, when the file system receives a read command, the file system loads the corresponding file stored in the storage device into the memory through the device driver. Alternatively, it may play an overall role related to file processing such as giving a name to a file stored in the storage device or placing a file in a predetermined area of the storage device for storage or retrieval.

However, the conventional file system is a structure developed for a PC-based environment, and is not suitable for a mobile device having recently enhanced multimedia functions. In other words, when performing a file read or write command, the conventional file system frequently needs to access the meta area of the file system, and it is very expensive to find necessary information in the meta area.

In particular, when the PC-based optimized file system is used in a mobile device environment where the CPU's computing power is low and data storage or reading speed is relatively slow, it is difficult to guarantee response time for read / write requests.

As a result, it becomes difficult to make real-time characteristics due to low performance, and causes problems such as power consumption increases as the number of accesses to the storage device increases.

Therefore, the technical problem to be achieved by the present invention is to provide a file system and a method of using the same that can reduce the number of times to access the storage device.

In addition, the present invention provides a file system and a method of using the same, which reduce the time required for a file processing command such as a read or write command by reducing the number of accesses of a storage device.

In addition, the present invention provides a file system and a method of using the same, which can reduce power consumption by reducing the number of accesses of a storage device.

Another object of the present invention is to provide a file system and a method of using the same, which can guarantee almost uniform responsiveness when performing a file processing command.

The file system for solving the technical problem includes a cluster region including N (N is a natural number) clusters and a cluster reference region including information on whether at least some of the N clusters are used. Each of the N clusters includes a header area in which information about a connection cluster connected to each of the N clusters is stored.

The cluster reference region may include a hash data region for searching for a cluster having a specific value among the N clusters.

The hash data area may include a cluster bank area and a cluster ready group area for using a task scheduling scheme of UCOS-II.

When the m th bit (m is a natural number) included in the cluster ready group region has a first logic value, at least one cluster corresponding to the m th row of the cluster bank region may be a busy cluster.

When the file system writes data to the k th (k is an integer greater than or equal to 0 and less than or equal to N) cluster, the file system is usable cluster based on information stored in the cluster bank area and the cluster ready group. Find information about the cluster; store information about the usable cluster found in the header area included in the k-th cluster; and use information about the cluster bank area corresponding to the found cluster as unavailable information. You can change it.

When the writing of the data to the k-th cluster is completed, the file system stores information indicating the end of data in a header area included in the k-th cluster, and the cluster bank corresponding to the found available cluster. Information about the area can be changed into usable information.

If the file system performs a read command of data stored in the k th cluster (k is an integer greater than or equal to 0 and less than or equal to N), the file system reads the data stored in the k th cluster and then k The data stored in the cluster corresponding to the information stored in the header area included in the first cluster may be read.

The mobile device for solving the technical problem includes a file system and a processor for performing file input and output to the storage device through the file system.

The mobile device may include at least one of a mobile phone, a personal digital assistant (PDA), a portable multimedia player (PMP), and a digital camera.

The method of using a file system to solve the technical problem is that when the file system writes a file to the k th (k is an integer greater than or equal to 0 and less than or equal to N) cluster of N (N is a natural number), The file system finding information on an available cluster based on information stored in a hash data area; storing information on the available cluster found in a header area included in the k-th cluster; and storing the k-th cluster. Writing to at least a portion of the file.

The method of using the file system may further include changing information on the cluster bank region corresponding to the found available cluster into unavailable information.

When writing of the data to the k-th cluster is completed, the file system stores information indicating the end of the file in a header area included in the k-th cluster, and the file corresponding to the available cluster found. The method may further include changing information about the hash data area into usable information.

The hash data area may include a cluster bank area and a cluster ready group area for using a task scheduling scheme of UCOS-II.

When the m th bit (m is a natural number) included in the cluster ready group area is a first logic value, at least one cluster corresponding to the m th row of the cluster bank area may be a busy cluster.

A method of using a file system to solve the technical problem is that the file system reads a file stored in a k th cluster (where k is an integer greater than or equal to 0 and less than or equal to N) among N (N is a natural number) clusters. The file system reads at least a portion of the file stored in the k-th cluster and reads at least a portion of the file stored in the cluster corresponding to information stored in a header area included in the k-th cluster. It includes.

The file system according to the present invention has the effect of reducing the size of the data area for meta data by storing the mixed metadata and data.

In addition, by substantially reducing the time required for cluster allocation and searching for a connected cluster, there is an effect that it is possible to provide almost uniform responsiveness when performing a file processing command.

In addition, by mixing and storing the metadata and data, the number of times of accessing the metadata area is reduced, thereby reducing the execution time of the file processing command and reducing power consumption.

In order to fully understand the present invention, the operational advantages of the present invention, and the objects achieved by the practice of the present invention, reference should be made to the accompanying drawings which illustrate preferred embodiments of the present invention and the contents described in the accompanying drawings.

In addition, in the present specification, when one component 'transmits' data to another component, the component may directly transmit the data to the other component, or through at least one other component. Means that the data may be transmitted to the other component.

On the contrary, when one component 'directly transmits' data to another component, it means that the data is transmitted from the component to the other component without passing through the other component.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Like reference numerals in the drawings denote like elements.

In the present specification, the file system is used to mean a structure of a storage device in which a file is stored, and at least a part of an operating system (OS) for accessing a file stored in the storage device and hardware for driving the file.

2 shows a schematic configuration of a conventional file system, and FIG. 3 shows a schematic structure of a file system according to an embodiment of the present invention.

First, referring to FIG. 2, a conventional file system includes a meta area 1 and a data area 2.

The data area 2 includes a file area 15 for storing actual files or data, and a directory area 14 for storing information on files stored in the file area 15.

In addition, the meta area 1 may store meta data (eg, a location of a file, a file size, a creation date, a property, etc.) necessary for managing the data area 15.

FIG. 2 illustrates a case in which a storage device is formatted in a file allocation table (FAT) file system format. The metadata includes a connection of a boot area 10, a reserved area 11, and a cluster. The information is stored in the FAT1 area 12 where information is stored, the FAT2 area 13 which is a copy of the FAT1 area, and the directory area 14 of the data area 2.

The boot area 10 may store data about a structure of a file system (for example, a type of file system, a start position of a FAT, a start position of a root directory, a cluster size, and the like). In addition, when the storage device is mounted on the system, the file system may read information stored in the boot area 10 to know information about the mounted storage device.

The reserved area 11 may include a copy of at least a portion of the boot area 10 as a reserved area, and may include some information preset in the system.

In the FAT1 area 12, connection information of the cluster of the data area 2 may be stored, and a copy of FAT1 may be stored in the FAT2 area 13.

In addition, the data area 2 may be divided into cluster units, and one cluster may be configured of several sectors.

As described above, in the conventional file system, the area for meta data (ie, the meta area 1 and the directory area 14) is relatively large, which means a reduction in the space for storing the actual data.

In contrast, referring to FIG. 3, a file system according to an exemplary embodiment of the present invention includes a cluster reference region 110 and a cluster region 120. Of course, the file system may further include a boot area 100.

The cluster region 120 includes N clusters (N is a natural number). The cluster is a unit in which data is stored, and one cluster may include a plurality of sectors. In addition, the file system according to an embodiment of the present invention can be used from cluster 0 as shown in FIG. This means that data is stored from cluster 2 in a conventional file system (eg, FAT32), and the regions corresponding to clusters 0 and 1 can use a wider data area than the system reserved. .

The cluster area 120 may of course include a directory area 121 and a data area 123.

The directory area 121 may store information about files stored in the data area 123 (for example, a location of a start cluster, a file name, etc.), and actual file data may be stored in the data area 123. have.

The size of the directory area 121 may vary dynamically according to the size or number of files stored in the data area 123. That is, the number of clusters included in the directory area 121 may vary. In addition, clusters included in the directory area 121 may not be continuous. For example, the clusters included in the directory area 121 may not be physically contiguous, such as the first cluster (cluster 0), the third cluster (cluster 2), the tenth cluster (cluster 9), etc. of the cluster area 120. Can be. However, the cluster included in the directory area 121 also includes header areas 120-0 to 120- (N-1), which will be described later, and the header areas 120-0 to 120- (N-1). Since information on the connection cluster is stored in the file system according to the embodiment of the present invention, the directory area 121 and the data area 123 may be distinguished from each other.

Meanwhile, each of the clusters may include header regions 120-0 to 120- (N-1). The header areas 120-0 to 120- (N-1) may store information on a connection cluster connected to each of the clusters.

For example, if data of the file AAA.txt is stored in clusters 3, 4, 5, 7, and 8, the header area 120-3 included in cluster 3 contains information about cluster 4 (for example, the address of cluster 4). ) Is stored in the header region 120-4 included in the cluster 4, and information about the cluster 5 (eg, the address of cluster 5) is stored, and the header region 120-5 included in the cluster 5 is stored in the header region 120-4 included in the cluster 5. Information about the cluster 7 (eg, the address of the cluster 7) is stored, and information indicating the end of the file (eg, end of file (EOF)) is stored in the header area 120-8 included in the cluster 8. Can be.

As a result, the cluster information corresponding to the cluster information stored in the FAT1 area 12 or the FAT2 area 13 in the conventional file system corresponds to the data area 2 of the conventional file system in the file system according to an exemplary embodiment of the present invention. Stored at 120.

Therefore, in the conventional file system, in order to read information of one cluster stored in the data area 2 and to read the next cluster, it is necessary to access the meta area 1 to read information about the connected cluster and then read the next cluster. In the file system according to an exemplary embodiment of the present invention, since the information of one cluster and the next cluster information stored in the cluster region can be read, the number of times of accessing the meta region 1 can be significantly reduced.

On the other hand, the header areas 120-0 to 120 (N-1) may exist at predetermined positions of each cluster including the header areas 120-0 to 120 (N-1).

For example, the header areas 120-0 to 120 (N-1) may exist in the first sector of each cluster. Therefore, while the file system reads the information of the cluster, the information present in the first sector can be used as information on the connected cluster, and the information present in the remaining sectors can be recognized as actual file data. Of course, the position in each cluster of the header areas 120-0 to 120 (N-1) may vary depending on implementation.

As a result, one of the great features of the file system according to an embodiment of the present invention is that the actual data and the metadata exist together in the cluster area 120, so that the processor can reduce the number of accesses to the storage device storing the file system. Is there.

The cluster reference region 110 may include information on whether at least some of the N clusters are used. That is, the cluster reference region 110 may include information indicating whether each of the clusters included in the cluster region 120 is currently in use. Therefore, when the file system executes a file write command and needs to write a file to one cluster and continuously write a file to the next cluster, the file system refers to the cluster reference area 110 to find a cluster that is not in use. The file can be written to the found cluster.

To this end, the cluster reference region 110 may include a hash data region for searching for a cluster having a specific value among the N clusters.

Hash means that if you want to find a specific value in a table that contains several key values randomly, you can change the key value to the address of the item by using a specific conversion function to find the table item with the desired key value. Means the way. In this case, the conversion function may be referred to as a hash function, and the table may be referred to as a hash table.

Thus, the hash data area may include information about the hash function and information about the hash table.

In addition, the hash table may include information on whether at least some of the N clusters are used as key values. For example, if there are N clusters included in the cluster area 120 according to an embodiment of the present invention, each cluster is in use, and the key value of the hash table is set to '0'. If set to '1', the hash table may be a hash table having N buckets. In addition, the address of the bucket can be set to have information about the cluster.

Therefore, if the file system is to find a cluster that is not in use, the file system needs to find a bucket having a key value '1' through a predetermined hash function. For example, if the first bucket among the buckets having a key value of '1' is the third bucket, it may mean a cluster in which the third cluster is not in use.

Of course, such a hash technique may have a different cost for retrieving a key value according to a bucket size, a number of slots, a hash function, or a collision processing method in a hash table. Since this hash technique is a widely known theory in the field of computational science or mathematics, a detailed description thereof will be omitted.

As a result, the file system according to an embodiment of the present invention has another feature in that it is possible to quickly search a cluster that is not in use by using this hash technique.

As an example of such a hash technique, an embodiment of the present invention describes a task scheduling technique of UCOS-II as an example. However, the scope of the present invention is not limited thereto.

For the task scheduling scheme of the UCOS-II, the cluster reference region 110 may include a cluster bank region and a cluster ready group region.

4 schematically illustrates a cluster bank and a cluster ready group for explaining a task scheduling scheme of UCOS-II according to an embodiment of the present invention.

4 illustrates that when there are 64 clusters, the cluster banks included in the cluster bank region may be configured in eight arrays composed of 8 bits. In addition, the cluster ready group ClusterRdyGrp included in the cluster ready group region may include 8 bits, and each bit may mean a row of the cluster bank.

For example, if the cluster ready group is set to bit '11111000', Cluster0 to 23 included in the third row of the cluster bank are in use, and there is an empty cluster in Cluster24 to 31 included in the fourth row. Can be. In addition, as a result of checking the bit in the fourth row of the cluster bank, if the bit is set to '11100000', it means that Cluster24 to 28 are in use and Cluster29 is an empty cluster.

Therefore, the empty cluster can be found more quickly than the conventional file system that sequentially searches the FAT to find an empty (not in use) cluster.

In addition, the cluster bank may function as a hash table, and the cluster ready group may serve as a hash function. Whenever data is written to or erased from the cluster area 120, at least one of the cluster bank or the cluster ready group may be changed in value.

In addition, a case of returning a used cluster (for example, data is deleted) will be described below. For example, when returning Cluster12, converting 12 to binary is bit '00001100'. Then, bits 3 to 5 of the bit '00001100' mean 2 rows descending by 1 in the Y direction of the cluster bank, and bits 0 through 2 are 4 in the X direction of the cluster bank. You can easily find Cluster # 12 because it means four columns to the left. Therefore, the value stored in the found cluster bank item may be changed to '1'.

When using the task scheduling scheme of UCOS-II as described above, in a conventional file system (for example, FAT32), 4 bytes are required to represent one cluster, and 64 * 4Byte = 256Byte to represent 64 clusters. It is necessary.

However, in the file system according to an exemplary embodiment of the present invention, 1 byte * 8 = 8 bytes are required to represent the cluster bank, and 1 byte is required to represent the cluster ready group, so a total of 9 bytes is required.

In other words, using the same technique as described above, it is possible to perform the operation more quickly and reduce the FAT area, which is Meta Data, to about 3%, compared to sequentially searching the FAT area in the conventional file system to find a cluster. It works.

FIG. 5 schematically shows a FAT area in a conventional file system, and FIG. 6 schematically shows a file system according to an embodiment of the present invention.

A method of performing a write command and a read command in a file system according to an embodiment of the present invention will be described with reference to FIGS. 5 and 6 as follows.

First, referring to FIG. 5, it is assumed that a file name and a start cluster shown in Table 1 are included in a directory area of a conventional file system (for example, FAT 32).

File Name Start cluster AAA.TXT 0x3 BBB.JPG 0xC CCC.MP3 0xF

And, if it has a FAT area as shown in Figure 5, it means that the cluster included in the directory area is cluster 2, 9, A, B, 11, the file AAA.TXT is cluster 3, 4, 5, 7 , It means stored in 8.

In addition, the file BBB.JPG is stored in the clusters C, D, and E, and the file CCC.MP3 is stored in the clusters F, 10, 12, 13, 14, 15, and 16.

Next, a process of performing a write command of the AAA.TXT file by the conventional file system is as follows.

First, when the application requests to save the AAA.TXT file in the conventional file system, the conventional file system searches the directory area to determine whether the AAA.TXT file exists. If there is no identical file name, the conventional file system searches the FAT to check the available cluster number, and determines the starting cluster (cluster 3).

Thereafter, information related to AAA.TXT is written to a directory entry (e.g., a file name, a start cluster (Cluster 3), etc.). Thereafter, data is stored in the starting cluster (cluster 3). Starting cluster (3 in cluster) Failed to store all the data in the AAA.TXT file. Search for the next cluster. That is, the FAT is searched to determine the cluster number that is available (not in use). The next available cluster is identified as 4, and it connects to cluster 4's data in cluster 4 and continues to store data.

In this manner, the conventional file system searches for a FAT when data storage is completed in cluster 4, and subsequently stores the AAA.TXT file in cluster 5. Thereafter, when data storage is completed in cluster 5, the FAT is searched, the AAA.TXT file is subsequently stored in cluster 7, and when data storage is completed in cluster 7, the FAT is searched, and cluster 8 is stored in the AAA. Then save the TXT file. Finally, when the storage of the AAA.TXT file is completed in the cluster 8, information such as file size and update time is written in the AAA.TXT related information in the directory area, and the execution of the file write command is completed.

As described above, when data storage is completed in one cluster, the conventional file system must search the FAT in order to search for a cluster to store data next. In addition, when a large number of files are stored in the storage device or frequent file creation and deletion operations are performed, many directories are created and cluster connection information stored in the FAT is also distributed.

In this case, in order to perform a task of finding a place where a file is located in a directory, finding an empty cluster, and checking information of a connected cluster, frequent access to the meta area is required.

On the other hand, referring to Figure 6, looking at the write command execution process of the file system according to an embodiment of the present invention, when the application program requests to save the AAA.TXT file to the file system, the file system searches the directory area AAA Make sure you have a .TXT file. If the same file name does not exist, a hashing scheme is used to determine the available starting cluster number (cluster 3).

In an embodiment of the present invention, an example of using a task scheduling scheme (ie, a cluster scheduling scheme) of UCOS-II is described as an example, but the scope of the present invention is not limited thereto.

The file system then writes information (eg, file name, start cluster, etc.) related to AAA.TXT to a directory entry.

Thereafter, before storing a part of the data of the file (AAA.TXT) in the starting cluster (cluster 3) or after storing a part of the data of the file in the starting cluster (cluster 3) the file system is a cluster. The next cluster number to be connected to the current cluster is identified through scheduling, and the next cluster number (cluster 4) is written in the header area of the starting cluster (cluster 3).

That is, the file system according to an exemplary embodiment of the present invention may identify a next available cluster number, write it into a header area, and store the data in any one cluster before storing data in any one cluster. Alternatively, after storing data in one of the clusters, the next available cluster number may be checked and written in the header area.

However, in the present specification, before storing data in any one cluster, a case in which the next available cluster number is checked, written in the header area, and the data is stored in any one cluster will be described as an example. The scope of the right is not limited thereto.

Thereafter, the file system checks the next cluster number (cluster 5) through cluster scheduling, writes the next cluster number (cluster 5) in the header area of the cluster 4, and then connects and stores data in the cluster 4.

In this way, the file system checks the next cluster number (cluster 7) through cluster scheduling, writes the next cluster number (cluster 7) in the header area of cluster 5, and then connects and stores data to cluster 5 do. Subsequently, the file system checks the next cluster number (cluster 8) through cluster scheduling, writes the next cluster number (cluster 8) in the header area of the cluster 7, and stores data in the cluster 7.

Finally, the file system checks the next cluster number (for example, cluster A) through cluster scheduling, writes the next cluster number (for example, cluster A) in the header area of cluster 8, and then connects data to cluster 8 Save it. However, since the cluster 8 is the last cluster, the next cluster previously allocated (for example, cluster A) is returned, and information indicating the end of the file (for example, End, EOF, etc.) is written in the header area of the cluster 8. The process of returning the next preallocated cluster is also possible at a low cost as described above.

Finally, the file system writes information such as file size, update time, etc. in the AAA.TXT related information in the directory area and completes a file write command.

As described above, in the embodiment of the present invention, even if a large number of files are stored in a storage device using a hashing technique (particularly, a cluster scheduling technique) or if a large number of directories are created when frequent file creation and deletion operations are performed, a fixed cost As a result, the next cluster number can be checked, thereby ensuring a uniform response when performing a write command.

On the other hand, when comparing the execution process of the read command, if the application requests a read command of the AAA.TXT file to the conventional file system, the directory is checked for the AAA.TXT file information (confirms that the starting cluster is Cluster 3). do.

Then it reads cluster 3, searches the FAT to identify the next cluster, and checks the next cluster (make sure the next cluster is 4).

Then it reads cluster 4, searches the FAT to identify the next cluster, and checks the next cluster (the next cluster is 5).

In this way, cluster 5 is read, the FAT is searched to identify the next cluster, and the next cluster is identified (the next cluster is 7). In addition, it reads cluster 7, searches the FAT to identify the next cluster, and checks the next cluster (the next cluster is 8). Finally, it reads cluster 8, searches the FAT to identify the next cluster, verifies that there is no next cluster (i.e. it is the last cluster), and completes the execution of the read command.

That is, in the conventional file system, the meta area must be searched every time the connected cluster is found, and the meta area is searched sequentially so that many files are stored in the storage device or frequent file creation and deletion operations are performed. In the case of high variance, it is expensive to search connected clusters and could not guarantee uniform responsiveness.

On the contrary, referring to FIG. 6, referring to a process of performing a read command of a file system according to an exemplary embodiment of the present disclosure, when an application program reads an AAA.TXT file from the file system, the file system reads a directory area. Check the AAA.TXT file information (make sure the starting cluster is Cluster 3). Then, cluster 3 is read, and the connection cluster (cluster 4) number written in the header area of cluster 3 is stored.

After reading cluster 3, it will start reading the cluster corresponding to the stored connection cluster (cluster 4) number. While reading cluster 4, the connection cluster (cluster 5) number written in the header area of cluster 4 is stored. Then, when cluster 4 is read out, the cluster corresponding to the stored connection cluster (cluster 5) number is started, and in this manner, the cluster is read to the last cluster (cluster 8) and the execution of the read command is completed.

As outlined above, in the file system according to an embodiment of the present invention, when a write and read command is executed, many files are stored in a storage device, or frequent file creation and deletion operations are performed to distribute cluster connection information. In this situation, since the metadata can be referred to at the same time as reading the actual data of the file (mixed storage of the meta data and the actual data), no additional storage device access occurs when performing the read operation. In addition, continuous writes are performed after an empty cluster is pre-allocated (Cluster Pre-Allocation), which ensures almost constant write and read responsiveness.

7 and 8 illustrate graphs for explaining responsiveness when a read / write command of a conventional file system and a file system according to an exemplary embodiment of the present invention is continuously performed.

Referring to FIGS. 7 and 8, when a file having a size of 100 KB is continuously written, the file system according to an embodiment of the present invention has almost uniform responsiveness (ie, response time), whereas in the case of a conventional file system, It can be seen that the response time is significantly increased because of the overhead of processing data.

In addition, as shown in FIG. 8, when the storage device is read and then continuously stored data is read, the file system according to an embodiment of the present invention exhibits almost constant responsiveness, whereas in the case of the conventional file system, If the cluster changes, the response time increases.

The file system according to an embodiment of the present invention may be implemented in a mobile device. The mobile device includes at least one of a mobile phone, a personal digital assistant (PDA), a portable multimedia player (PMP), and a digital camera.

In addition, in the file system according to an exemplary embodiment of the present invention, the size of each cluster may be set to be larger for a multimedia environment.

For example, when a 1 GB SD Card is formatted in a conventional file system format (e.g., FAT32), the cluster size is fixed at 4 KB. For example, if you store 4MB of MP3 files, you need 1024 clusters ((4 * 1048576Byte) / (4 * 1024Byte) = 1024). That is, 1024 FAT area updates occur. If the cluster size is increased, the overhead of updating the FAT area can be reduced.

Accordingly, in an embodiment of the present invention, in consideration of the characteristics of the mobile device that mainly plays / generates multimedia data, the size of the cluster may be set larger than that of the conventional file system, thereby reducing overhead.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS In order to better understand the drawings cited in the detailed description of the invention, a brief description of each drawing is provided.

1 is a schematic diagram illustrating a general file system.

2 shows a schematic configuration of a conventional file system.

3 shows a schematic structure of a file system according to an embodiment of the present invention.

4 schematically illustrates a cluster bank and a cluster ready group for explaining a task scheduling scheme of UCOS-II according to an embodiment of the present invention.

5 schematically shows a FAT area in a conventional file system.

6 schematically illustrates a file system according to an embodiment of the present invention.

7 and 8 illustrate graphs for explaining responsiveness when a read / write command of a conventional file system and a file system according to an exemplary embodiment of the present invention is continuously performed.

Claims (15)

A cluster region including N (N is a natural number) clusters; And A cluster reference region including information on whether at least some of the N clusters are used; Each of the N clusters includes a header area in which information about a connection cluster connected to each of the N clusters is stored. The method of claim 1, wherein the cluster reference region, And a hash data area for finding a cluster having a specific value among the N clusters. The method of claim 2, wherein the hash data area, A cluster bank area for using the task scheduling scheme of UCOS-II; And File system containing the cluster ready group area. The method of claim 3, wherein when the m th bit (m is a natural number) included in the cluster ready group region is a first logic value, And at least one cluster corresponding to the m th row of the cluster bank area is a cluster in use. The method of claim 3, wherein If the file system writes data to the k th cluster (k is an integer greater than or equal to 0 and less than or equal to N), The file system finds information on an available cluster based on information stored in the cluster bank area and the cluster ready group, The header area included in the k-th cluster stores information about the available cluster found. A file system for changing the information on the cluster bank area corresponding to the found available cluster to unusable information. The method of claim 5, wherein the file system, When writing of the data to the k-th cluster is completed, In the header area included in the k-th cluster, information indicating the end of data is stored. And a file system for changing the information on the cluster bank area corresponding to the found available cluster into usable information. The method of claim 3, wherein When the file system performs a read command of data stored in the k th cluster (k is an integer greater than or equal to 0 and less than or equal to N), The file system reads the data stored in the cluster corresponding to the information stored in the header area included in the k-th cluster after reading the data stored in the k-th cluster. A file system according to claim 1; And And a processor configured to perform file input / output to the storage device through the file system. The method of claim 8, wherein the mobile device, A mobile device that is one of a cell phone, a personal digital assistant (PDA), a portable multimedia player (PMP), and a digital camera. In the method of using the file system, If the file system writes a file to the k th cluster (where k is an integer greater than or equal to 0 and less than or equal to N) of N clusters, where N is a natural number, The file system finding information on an available cluster based on information stored in a hash data area; Storing information about the usable cluster found in a header area included in the k-th cluster; And, Writing at least a portion of the file to the k-th cluster. The method of claim 10, wherein the file system is used. And changing the information on the cluster bank area corresponding to the found available cluster into unusable information. The method of claim 11, wherein the file system is used. When writing of the file to the k-th cluster is completed, The file system storing information indicating the end of the file in a header area included in the k-th cluster; And And changing the information about the hash data area corresponding to the found available cluster into usable information. The method of claim 10, wherein the hash data area, A cluster bank area for using the task scheduling scheme of UCOS-II; And A method of using a file system including a cluster ready group area. 15. The method of claim 13, wherein when the m th bit (m is a natural number) included in the cluster ready group region is a first logic value, At least one cluster corresponding to the m th row of the cluster bank area is a cluster in use. In the method of using the file system, When the file system performs a read command of a file stored in the k th cluster (where k is an integer greater than or equal to 0 and less than or equal to N) of N clusters, The file system reading at least a portion of the file stored in the k th cluster; And And reading at least a portion of the file stored in the cluster corresponding to the information stored in the header area included in the k-th cluster.

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