JP4241200B2 - Data sharing system and method, and data sharing program - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a data sharing system, and more particularly to a system in which a plurality of clients connected to a network share the same data. The present invention also relates to a data sharing method and a data sharing program.
[0002]
[Prior art]
In a server / client system in which a plurality of computers such as an in-house LAN are connected to a network, the server computer is often used as a file server. In such a case, a plurality of users can access a shared file at the same time. is there. As described above, when a plurality of users refer to the same file, the disk capacity used by the server computer is only one file, which is efficient.
[0003]
However, since the shared file in the server computer can be accessed by a plurality of users, there is a possibility that it will be changed or deleted. Therefore, each user may want to save the shared file separately. In such a case, a usage method is used in which a copy of the file is created in a file area managed by each user.
[0004]
Further, in the method of managing the shared file using the server computer, there is a disadvantage that the shared file is deleted as described above. Therefore, there is a network system including a plurality of client computers without the server computer. In such a case, a shared file reference information distributed and held in each computer is prepared, the shared file reference information is exchanged between the computers, and a file is shared thereby. . Such a technique is disclosed in Patent Document 1.
[0005]
[Patent Document 1]
JP 2002-244906 A
[0006]
[Problems to be solved by the invention]
However, the conventional example has the following disadvantages. First, storing the same file in a plurality of areas causes a problem that a lot of disk capacity is wasted.
[0007]
Further, when the server computer is not arranged, it is necessary for all the computers to store or distribute the shared file reference information, and there arises a problem that the disk capacity of each computer is used unnecessarily. There may also be network congestion.
[0008]
On the other hand, when managing with individual files, if the original file is changed, each file will not be changed, so the old file will be saved and the data will not be consistent. Also occurs.
[0009]
OBJECT OF THE INVENTION
The present invention improves the inconveniences of the above-described conventional example, and in particular, facilitates management of shared files by a plurality of computers and reduces the disk capacity of the computer storing the shared files. And a method and a data sharing program.
[0010]
[Means for Solving the Problems]
Therefore, the present invention includes a server computer connected to a plurality of client computers via a network, and the server computer stores physical data of files shared by the plurality of client computers in the server computer. A data sharing system that manages shared files by displaying pointers that refer to physical data on each computer, and is a replication target when a server computer receives a replication command for a predetermined file from a client computer A pointer generation function for generating a new pointer that points to a pointer of a predetermined file as a reference destination, and association data between the pointer of the predetermined file and the new pointer are recorded in a file management table formed in the server computer. And the management table storage function to, A pre-change data storage function that temporarily stores and holds data before the change of the physical data when a change occurs in the physical data of the predetermined file, and refers to the physical data after the change of the physical data A change notification function for notifying the client computer corresponding to the new pointer associated with the pointer that the physical data has changed and asking whether to comply with the change, and a physical notification from the client computer that received the notification A physical data migration function for associating a new pointer with direct reference to the data before the physical data change when receiving notification that the data change is not followed, and deleting the associated data related to the new pointer; It has the structure of having.
[0011]
With this configuration, when the same file is copied to different areas in the file server, a new pointer that further refers to a pointer indicating the physical data to be copied is generated. Data relating these two pointers is stored in a file management table in the file server. For this reason, when referring to a duplicated file later, by specifying a new pointer, the original pointer is referred to based on the association data in the file management table, and the physical that is referenced by the original pointer. You can access the data. Therefore, file replication can be realized and disk capacity can be reduced only by generating pointers and association data with a capacity smaller than the physical data capacity of the file without actually replicating the physical data of the file itself. Can do.
[0013]
The change notification function allows the client computer to change the physical data when the client computer accesses a new pointer associated with the pointer that refers to the physical data after the physical data has changed. It may be configured to have a function of notifying information indicating that it has occurred and asking whether to follow such a change.
[0014]
In the above configuration, the change of physical data may include a configuration in which the physical data is deleted.
[0015]
With such a configuration, first, when the contents of the physical data referred to via the pointer are changed, such as being updated or deleted, the physical data before the change is temporarily saved. Then, when a new pointer is accessed immediately after the change or after the change, information indicating that the contents of the physical data referred to is changed is notified to the client computer using the new pointer via the original pointer. Whether to follow such changes. On the other hand, if it follows, the changed physical data is referred to as it is, but if it does not follow, the new pointer directly refers to the physical data before the change. Therefore, it is possible to prevent the shared file data from being changed or deleted without permission, and to prevent data loss or the like.
[0016]
Further, in the present invention, a server computer connected to a plurality of client computers via a network is provided. Stores physical data stored on multiple client computers via pointers stored on server computers A file monitoring function for monitoring files, and when the same file is found among the monitored files, the association data is generated by associating other pointers with one specific pointer among the pointers of these same files. A management table storage function for storing association data in a file management table formed in the server computer; a physical data deletion function for deleting physical data of other files while leaving physical data referred to by a specific pointer; It has the structure of having.
[0017]
With this configuration, first, files stored in computers on the same network are periodically monitored by the server computer. When the same file is found, a pointer that refers to physical data of a specific file in the file is selected, and data that associates the pointer of another file with the specific pointer is generated and stored in the server computer. . At the same time, the physical data of files other than the specific file is deleted. Therefore, when referring to another file having the same content as the specific file from the client computer, the specific pointer is referenced from the association data by referring to the pointer of the other file, and the physical data of the specific file is You can refer to it. As a result, it is possible to suppress duplication of the same data in each computer while maintaining the data contents, and to reduce the disk capacity.
[0018]
Further, the server computer is connected to a plurality of client computers via a network and stores and manages files transmitted from the client computers. Stores physical data stored on the server computer via a pointer stored on the server computer A file monitoring function for monitoring files, and when the same file is found among the monitored files, the association data is generated by associating other pointers with one specific pointer among the pointers of these same files. A management table storage function for storing association data in a file management table formed in the server computer; a physical data deletion function for deleting physical data of other files while leaving physical data referred to by a specific pointer; It is also equipped with a configuration.
[0019]
With such a configuration, first, a file transmitted from a client computer and stored in the server computer is monitored by a server computer used as a storage service or the like. When the same file is found, a pointer that refers to physical data of a specific file in the file is selected, and data that associates the pointer of another file with the specific pointer is generated and stored in the server computer. . At the same time, the physical data of files other than the specific file is deleted. Therefore, when the client computer refers to the file stored in the server computer, the specific pointer is referred to from the association data by referring to the pointer of the other file, and the physical data of the specific file is referred to. The same data as the stored contents can be used. Thereby, it is possible to suppress duplication of the same data in the server computer while maintaining the data content, and to reduce the disk capacity.
[0020]
In the present invention, a server computer connected to a plurality of client computers via a network stores physical data of a file shared by the plurality of client computers in the server computer and refers to the physical data. A data sharing method for managing a shared file by displaying a pointer on each computer when the server computer receives a copy instruction for a predetermined file stored in the server computer from a client computer. In the server computer, a pointer generation step for generating another pointer that points to the pointer of the file to be copied as a reference destination and association data between the pointer of the predetermined file and the newly generated other pointer are stored in the server computer. A management table storing step for storing in the formed file management table, and a pointer to which the server computer reads association data from the file management table when a new pointer is accessed from the client computer and is associated with the new pointer A physical data reference step for referring to physical data via Before-change data storage step in which the server computer temporarily stores and holds the data before the change of the physical data when the change occurs in the physical data itself of the predetermined file at least after the management table storage step, and the server computer Whether or not to notify the client computer corresponding to the new pointer associated with the pointer that refers to the physical data after the change has occurred in the physical data and follow the change The change notification process that asks for this, and when the server computer receives a notification from the notified client computer that it does not follow the physical data change, the new pointer directly refers to the data before the physical data change. Physical data that associates and deletes the association data for the new pointer And the transition process A data sharing method is also provided.
[0022]
A server computer connected to a plurality of client computers via a network Stores physical data stored on multiple client computers via pointers stored on server computers A file monitoring process for monitoring a file, and when the server computer finds the same file among the monitored files, another pointer is associated with one specific pointer among the pointers of the same file, and the association data A management table storage step for storing the association data in a file management table formed in the server computer, and the server computer leaves the physical data referenced by a specific pointer to store the physical data of other files. There is also provided a data sharing method including a physical data deleting step of deleting.
[0023]
Further, a server computer connected to a plurality of client computers via a network and storing and managing files transmitted from the client computers is provided: Stores physical data stored on the server computer via a pointer stored on the server computer A file monitoring process for monitoring a file, and when the server computer finds the same file among the monitored files, another pointer is associated with one specific pointer among the pointers of the same file, and the association data A management table storage step for storing the association data in a file management table formed in the server computer, and the server computer leaves the physical data referenced by a specific pointer to store the physical data of other files. There is also provided a data sharing method including a physical data deleting step of deleting.
[0024]
In the present invention, physical data of a file shared by a plurality of client computers is stored, and a shared file is managed by displaying a pointer referring to the physical data on the client computer. When a server computer connected via a network receives a copy instruction for a predetermined file stored in the server computer from a client computer, another pointer that points to the pointer of the file to be copied as a reference destination A pointer generation function for generating, a management table storage function for storing association data between a pointer of a predetermined file and another pointer newly generated by the server computer in a file management table formed in the server computer, A physical data reference function to refer to the physical data via a pointer new pointer is associated with reading data associated from the file management table when over server computer an access to a new pointer from the client computer, When a change occurs in the physical data itself of a predetermined file in the server computer, the data storage function before change temporarily stores and holds the data before the change of the physical data, and the physical data after the change occurs in the physical data. A change notification function for notifying the client computer corresponding to the new pointer associated with the pointer that refers to the data that the physical data has changed and asking whether to comply with the change, and received the notification A physical data migration function for associating a new pointer with direct reference to the data before the physical data change when receiving a notification from the client computer that the physical data change is not followed, and deleting the associated data related to the new pointer When, A data sharing program is also provided to achieve this.
[0026]
In the present invention, a server computer connected to a plurality of client computers via a network, Physical data stored on the plurality of client computers is stored via pointers stored on the server computer A file monitoring function for monitoring files, and when the same file is found among the monitored files, the association data is generated by associating other pointers with one specific pointer among the pointers of these same files. A management table storage function for storing association data in a file management table formed in the server computer; a physical data deletion function for deleting physical data of other files while leaving physical data referred to by a specific pointer; A data sharing program is also provided to achieve this.
[0027]
Further, a server computer connected to a plurality of client computers via a network and storing and managing files transmitted from the client computers, Stores physical data stored on the server computer via a pointer stored on the server computer A file monitoring function for monitoring a file, and when the same file is found among the monitored files, association data is generated by associating another pointer with one specific pointer among the pointers of the same file. A management table storage function for storing association data in a file management table formed in the server computer; a physical data deletion function for deleting physical data of other files while leaving physical data referred to by a specific pointer; A data sharing program is also provided to achieve this.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
<First Embodiment>
A first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a block diagram showing the configuration of the first embodiment of the present invention. FIG. 2 is a schematic diagram showing the state of data in the present embodiment. FIG. 3 is a sequence diagram showing the operation of the system.
[0029]
(overall structure)
As shown in FIG. 1, the data sharing system in this embodiment includes a server computer 3 in which a plurality of client computers 1 are connected via a network 2. A file shared by a plurality of client computers 1 is stored in the server computer 3, and the server computer 3 manages these shared files. This will be described in detail below.
[0030]
(Client computer)
The client computer 1 is a client-side computer that constructs a server / client system with the server computer 3 and has access authority to the server computer 3. The computer is a general computer and includes a calculation device such as a CPU having a predetermined information processing capability and a storage device such as a hard disk having a predetermined storage capacity, and is connected to the server computer 3 via the network 2. A communication device is also provided as possible.
[0031]
In this embodiment, the client computer 1 is a computer used by a user (client) in the same organization such as a company, and a file shared with other users is stored in the server computer 3 as will be described later. It comes to memorize. Therefore, it is possible to access the server computer 3 to generate a shared file, update the data content of an existing shared file, or delete it.
[0032]
(network)
In this embodiment, the network 2 is an intranet that operates only within a specific company, or a specific network that communicates using a protocol other than TCP / IP. However, the Internet may be a communication line such as a TCP / IP protocol using a dedicated line, a telephone line, a wired line such as a CATV cable, or a wireless line such as a mobile phone line.
[0033]
(Server computer)
The server computer 3 is accessible to the client computer 1 and manages the shared file so that the client computer 1 can use it. In the present embodiment, it is a file server in a specific in-house LAN. The configuration is a general server computer, which includes a calculation device such as a CPU having a predetermined information processing capability and a storage device such as a hard disk having a predetermined storage capacity, and can be connected to the network 2. A communication device is also provided.
[0034]
Here, functions of the server computer 3 will be described. The functions of the server computer 3 described below can be realized by incorporating such a function program into the CPU of the computer. That is, the data sharing program is stored in a storage device such as a hard disk of the server computer 3 and is read out by the CPU, whereby a functional block is constructed in the CPU. The program is stored in a portable medium such as a CD-ROM and may be provided to the server computer 3 or may be downloaded from another computer on the network and provided. The same applies to other embodiments described later.
[0035]
First, as a basic file server function, the server computer 3 stores physical data of a file shared by a plurality of client computers 1 in the server computer 3, and sets pointers that refer to the physical data for each of them. It has a function of managing shared files by displaying them on a computer. Details of this function will be described with reference to FIG.
[0036]
First, when a recording request for a file (A) is received from a predetermined client computer (A) 1a (see arrow A1), file display data F10 is displayed in the storage device 31 of the server 3 as data for displaying the file (A). Generated. At the same time as the file display data F10 is created, the data content of the file itself is stored in the disk 31 in association with the file display data as a physical image P10 (physical data). In FIG. 2 and the following text, the file display data F10 is simply represented as “file F10”, and the physical image P10 is represented as “image P10”. The same applies hereinafter.
[0037]
At this time, the file F10 serves as a pointer for referring to the physical image of the file.
[0038]
In this way, the client computer (A) 1a, the client computer (B) 1b, and the like can access the image P10 that is the data content via the file F10.
[0039]
The server computer 3 has a pointer generation function for generating a new pointer indicating a pointer of a predetermined file to be copied as a reference destination when receiving a copy instruction for the predetermined file from the client computer 1, and a predetermined file And a management table storage function for storing association data between a file pointer and a new pointer in a file management table formed in the server computer 3.
[0040]
These functions will also be described in detail with reference to FIG. Here, for example, the file F10 is accessed from a client computer (B) 1b different from the client computer (A) 1a that generated the above-described file F10, and the file F10 is stored in another area of the hard disk 31 (for example, a client Consider a case where data is stored in a computer (B) 1b that can be freely used.
[0041]
First, in the pointer generation function, when a file F10 is accessed by the client computer (B) 1b (see arrow A2) and a copy command for the file F10 is received, a new file F11 that refers to the file F10 is first created. Generate. That is, file display data F11 as a new pointer pointing to the file F10 is generated (see arrow A3).
[0042]
The management table storage function stores association data representing the relationship between the generated file F11 and the reference file F10 in a pointer repository R10 (file management table) provided in advance in the hard disk 31 (arrow). (See A4). At this time, the file F11, which is a new pointer, becomes the reference source, and the file F10 is represented as the reference destination.
[0043]
The server computer 3 also has a function of referring to the image P10 from the new file F11 along with the function of copying the file described above. Specifically, first, when the client computer (B) 1b accesses the copied file F11, it is checked with reference to the pointer repository R10 whether or not the file F11 is associated with another file. At this time, when association data related to the file F11 is found as shown in FIG. 2, it is read out to recognize that the file F11 refers to the file 10. Thereby, the image P10 can be referred to from the file F11 via the file F10.
[0044]
(Operation)
Next, the operation of the entire system in the present embodiment will be described with reference to the sequence diagram of FIG. First, the shared file is transmitted from the client computer (A) 1a to the server computer 3, and an instruction is given to store it in the server computer 3 (step S1). In response to this, the server computer 3 creates file display data F10 representing the transmitted shared file, creates a physical image P10 that is the data itself, and stores it in the hard disk 31 (step S2).
[0045]
Subsequently, there is an access to the file F10 from another client computer (B) 1b, and an instruction is given to copy the file F10 to the disk area on the server computer 3 handled by the client computer (B) 1b (step S3). Receiving this, the server computer 3 first creates only the file display data F11 as a new pointer referring to the file display data F10 that is the pointer of the file to be copied (step S4). Along with this, association data indicating that the file F11 refers to the file F10 is stored in the pointer repository R10 (step S5). Therefore, at this time, even if the file is copied, the physical image P10 is not copied to another area. As a result, file duplication is realized by generating pointers and association data having a smaller capacity than the data capacity of the physical data without actually copying the physical data of the file, thereby reducing the disk capacity. be able to.
[0046]
Access to the copied file F11 is performed as follows. When a request for browsing the file F11 is issued from the client computer (B) 1b to the server computer 3 (step S6), the server computer 3 first checks the pointer repository R10 to determine whether there is associated data that uses the file F11 as a reference source. Find out. If there is such association data, the data is read (step S7). Since the reference destination of the file F11 is known by referring to this, the file F10 is referred to from the file F11, and the physical image P10 indicated by the file F10 is accessed and read (step S8). After that, the server computer 3 transmits the read image P10 to the client computer (B) 1b to be displayed on the client computer (B) 1b (step S9), and the client computer (B) 1b receiving this browses the image P10. be able to.
[0047]
As described above, even if the physical image of the file is not actually copied on the disk, the same effect as that obtained by copying can be obtained, and the disk use capacity can be reduced as described above.
[0048]
<Second Embodiment>
Next, a second embodiment of the present invention will be described with reference to FIGS. Among these, FIGS. 4 to 5 are explanatory diagrams in the case of updating the contents of the shared data, and FIGS. 6 to 7 are explanatory diagrams in the case of deleting the shared data. 4 and 6 are explanatory diagrams showing the state of the file, and FIGS. 5 and 7 are flowcharts showing the operation of the system.
[0049]
(Constitution)
The data sharing system according to the present embodiment has substantially the same configuration as that shown in the first embodiment described above, and each client receives data when the content of the shared file is changed, such as updated or deleted. It has a configuration that can cope with changes in content.
[0050]
Specifically, the CPU of the server computer 3 includes a pre-change data storage function that temporarily stores and holds data before the change of the physical data when a change occurs in the physical data of a predetermined file, After the data has changed, the client computer corresponding to the new pointer associated with the pointer that refers to the physical data is notified of the information indicating that the physical data has changed, and asked whether or not to follow the change. The change notification function is associated with the new pointer so that the new pointer directly refers to the data before the change of the physical data when the notification notifying that the change of the physical data is not followed from the notified client computer. And a physical data migration function for deleting the association data. Each of these functions will be described more specifically with an example when data is updated or deleted.
[0051]
First, the storage status of data in the server computer 3 is as shown in FIG. That is, the file F10 (pointer) of the shared file that is the reference destination created by the client computer (A) 1a and the image P10 that is physical data thereof are stored, and this is copied by the client computer (B) 1b. The file F11 refers to the file F10 and refers to the image P10. Then, association data indicating that the file F11 refers to the file F10 is stored in the pointer repository R10. In this state, it is assumed that a command to update or delete the data itself image P10 of the file 10 that is a shared file is issued from the client computer (A).
[0052]
When an instruction to change or delete the image P10 is issued, the pre-change data storage function temporarily stores and holds the image P10 in a memory such as a RAM or register in the server computer 3 before changing or deleting the image P10. Then, after saving, the image P10 referred to by the file F10 is updated or deleted according to the instruction of the client computer (A) 1a.
[0053]
Then, the change notification function notifies the client computer (B) 1b that created the file F11 that the image P10 has been updated or deleted, and asks whether to follow this. At this time, the fact that the creator of the file F11 is the client computer (B) 1b is identified from the computer name, IP address, etc. by referring to the data stored in the header part of the file F11. Make a notification. However, the change notification function is not limited to performing notification immediately after a change is made. After the change, when the file F11 is accessed from the client computer (B) 1b, the fact may be notified to ask whether or not to follow the update or deletion. At this time, the image P10 before update and before deletion remains stored.
[0054]
When the physical data migration function receives notification from the client computer (B) that the image P10 is not changed or deleted, the physical data migration function sets the image P10 stored in the memory or the like as a reference destination of the file F11. . That is, the association data set so that the file F11 refers to the file F10 is deleted from the pointer repository R10. Thereby, if the file F11 is referred, the image P10 before a change can be browsed.
[0055]
Note that the server computer 3 stores information on whether or not the new pointer (file F11) as the reference source depends on the change of the physical data (image P10) of the pointer (file F10) as the reference destination. You may memorize | store in memory beforehand by the instruction | indication from the client (B) who produced the pointer. When the file change instruction is received, if the information is “not dependent”, the image P10 before the change may be associated with the pointer without notifying the client. In this way, by setting in advance regarding data that is difficult to change without permission, alteration of data can be suppressed.
[0056]
(Operation)
Next, the operation in this embodiment will be described. First, a case where data is updated will be described with reference to FIGS. FIG. 4A shows a case where the update is accepted, and FIG. 4B shows a case where the update is not accepted.
[0057]
First, as described above, as shown in the upper diagram of FIG. 4A, the file F11 refers to the image P10 that is the contents of the file F10 via the file F10. At this time, it is assumed that there is an instruction to update the file F10 from the client computer (A) 1a (step S101). Then, first, the image P10 before update is temporarily stored in the memory (step S102), and then an updated new image P11 is created (step S103). That is, as shown in the lower diagram of FIG. 4A, the physical data referred to by the file F10 is updated to the image P11.
[0058]
Subsequently, it is checked whether or not there is information indicating that the file F11 depends on the file F10 in the memory (step S104). The client computer (B) 1b that created the file F11 is notified and confirmed (step S105). At this time, if the setting is not to be notified (determination is negative in step S105), or if notification is received and update permission information is returned (determination is positive in step S106), association in the pointer repository R10 is performed. The data is not changed, and the file F11 remains in the state of referring to the file F10. That is, when referring to the file F11, the image P11 updated through the file F10 is referred to.
[0059]
On the other hand, when information indicating that the file F11 does not depend on the file F10 exists (No in step S104), or when the server computer 3 receives information indicating that updating is not permitted from the client computer (B). (No determination in step S106), the pre-update image P10 temporarily stored in the memory is read and set as a direct reference destination of the file F11 (step S107). The situation at this time is shown in the lower part of FIG. Then, the association data that the file F11 refers to the file F10 is deleted from the pointer repository R10 (step S108). Then, the file F10 refers to the updated image P11, and the file F11 refers to the image P10 before the update.
[0060]
Thereby, the client computer (B) can suppress that the data of the copied shared file is updated without permission.
[0061]
Next, a case where data is deleted will be described with reference to FIGS. FIG. 6A shows a case where the deletion is accepted, and FIG. 6B shows a case where the deletion is not accepted.
[0062]
First, as described above, as shown in the upper diagram of FIG. 6A, the file F11 refers to the image P10 that is the contents of the file F10 via the file F10. At this time, it is assumed that there is an instruction to delete the file F10 from the client computer (A) 1a (step S201). Then, first, the image P10 before update is temporarily stored in the memory (step S202), and then the image P10 directly referred to by the file F10 is deleted (step S203). That is, as shown in the lower diagrams of FIGS. 6A and 6B, the file F10 and the image P10 are deleted.
[0063]
Subsequently, it is checked whether or not there is information indicating that the file F11 depends on the file F10 in the memory (step S204). The client computer (B) 1b that created the file F11 is notified and confirmed (step S205). At this time, if the setting is not to be notified (determination is negative in step S205), or if notification of deletion permission is sent back (determination is positive in step S206), the pointer repository R10 contains As a matter of course, the file F11 is deleted because there is no data to be referred to. That is, the lower diagram of FIG.
[0064]
On the other hand, when information indicating that the file F11 does not depend on the file F10 exists (No in step S204), or when the server computer 3 receives information indicating that updating is not permitted from the client computer (B). (No determination in step S206), the pre-update image P10 temporarily stored in the memory is read and set as a direct reference destination of the file F11 (step S207). The state at this time is shown in the lower part of FIG. Since the file F11 has already been deleted, the association data that the file F11 refers to the file F10 is deleted from the pointer repository R10 (step S208). Then, the file F10 refers to the image P10 before deletion.
[0065]
As a result, the client computer (B) can prevent the duplicated shared file data from being deleted without permission.
[0066]
<Third Embodiment>
Next, a third embodiment of the present invention will be described. In the present embodiment, the shared file is duplicated by a technique almost similar to the technique in the first embodiment described above. However, the computer storing the shared file to be copied is different from the computer to which the shared file is copied.
[0067]
For example, in a server / client system connected to the network 2, a file stored in one client computer is copied to the other client computer. In such a case, an image that is physical data of a file and a pointer that refers to the image are stored in one client computer, and only a new pointer that refers to the pointer is created in the other client computer. . Data that associates the new pointer with the pointer of the copy source file is stored in the pointer repository of the server computer 3.
[0068]
By doing so, the disk capacity of each computer can be saved on the same network as described above.
[0069]
<Fourth Embodiment>
Next, a fourth embodiment of the present invention will be described. Even in the present embodiment, the system is configured by the server / client system in the same manner as described above, but there is no file shared by the client. That is, the same file is searched for among the files stored in each client computer, and these are managed as shared files by the method described in the other embodiments described above.
[0070]
For this reason, the server computer 3 in this embodiment is monitored with a file monitoring function for monitoring a file in which physical data is stored via a pointer to a plurality of client computers 1 connected via the network 2. A management table storage function for storing the associated data as a file management table in the server computer by associating each pointer of the file with the specific pointer when the same file is found, and a specific pointer A physical data deletion function for deleting physical data of other files while leaving physical data referred to. These functions will be described in detail.
[0071]
First, in the file monitoring function, the server computer 3 circulates the client computer 1 in the organization, for example, the client computer 1 connected by the in-house LAN, and examines data stored in these. At this time, for example, the header portion of the file is monitored, and the data type, capacity, creator, creation date, etc. are read and listed.
[0072]
Further, the management table storage function recognizes files having the same header part information as described above as the same file. When a plurality of identical files are found, one of these files is selected, and a pointer that refers to the physical data of the file is set as a specific pointer. The pointer also serves as a file display displayed on the client computer 1. Further, the pointer of another file having the same content as the identified file, that is, another pointer that refers to the physical data of the other file is associated with the specific pointer to generate the associated data. And stored in the pointer repository R10 in the server computer 3.
[0073]
Then, the physical data deletion function deletes the physical data of another file that is directly referred to by another pointer that refers to the specific pointer, while leaving the physical data directly referred to by the specific pointer.
[0074]
The management table storage function selects one of the same files as a specific file, but it may be selected in consideration of the performance of the client computer 1 storing the file and the free disk capacity. For example, one having a high CPU processing speed or one stored in a computer with a large free disk capacity is selected. Thereby, since the image which is the physical data of the same file is deleted from other computers, the disk capacity can be more effectively reduced.
[0075]
Then, when the client computer 1 that uses another file from which the physical data has been deleted accesses the file, the client computer 1 refers to the pointer repository R10 of the server computer 3 to refer to the specific pointer, and displays the image. You can refer to it.
[0076]
<Fifth Embodiment>
Next, a fifth embodiment of the present invention will be described. In this embodiment, the configuration is almost the same as that of the fourth embodiment, but the same file is used as shared data among the files transmitted from each client computer 1 to the server computer 3 and stored. is there. For example, when the server computer 3 provides a storage service, the client computer 1 transmits its music file, image file, video file, etc. to the server computer 3 and stores it in the server computer 3. It is to leave.
[0077]
To realize this, when the server computer 3 finds the same file among the monitored files and the file monitoring function for monitoring the file in which the physical data is stored in the server computer 3 via the pointer A management table storage function for associating each pointer of the file with a specific pointer of the file and storing the associated data as a file management table in the server computer, and leaving physical data referenced by the specific pointer. And a physical data deleting function for deleting physical data of the file. These functions can be realized by providing a data sharing program to a server computer and incorporating it into a CPU.
[0078]
As a result, even if the owners are different, it is only necessary to save one file for the same music file, etc., and the other files can be managed with pointers and associated data, thus saving disk space. Can do.
[0079]
【The invention's effect】
Since the present invention is configured and functions as described above, according to this, when copying the same file to a different area in the file server, the physical data to be copied is not replicated, and this is indicated. A new pointer that further refers to the pointer is generated, and the data for associating these pointers is stored in the file management table in the file server. Therefore, by specifying the new pointer, the association in the file management table is specified. The original pointer is referred to based on the data, the physical data referenced by the original pointer can be accessed, and the same effect as that obtained by copying can be obtained. Therefore, file replication can be realized and disk capacity can be reduced only by generating pointers and association data with a capacity smaller than the physical data capacity of the file without actually replicating the physical data of the file itself. It has an unprecedented excellent effect of being able to.
[0080]
In addition, when the contents of physical data referenced via a pointer are updated or deleted, the physical data before the change is temporarily saved, and a new pointer is accessed immediately after or after the change. When this happens, the client computer using the new pointer is notified of information indicating that the contents of the physical data to be referred to have been changed via the original pointer, and it is asked whether or not to comply with the change. If this is not followed, the new pointer will directly refer to the physical data before the change, so that the data in the shared file will not be changed or updated without permission. Loss etc. can be suppressed.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration in a first embodiment of the present invention.
FIG. 2 is an explanatory diagram showing a data state in the first embodiment.
FIG. 3 is a sequence diagram showing an operation of the system in the first embodiment.
FIGS. 4A and 4B are explanatory diagrams showing the state of data in the second embodiment, in particular, an explanatory diagram when updating the contents of shared data.
FIG. 5 is a flowchart showing the operation of the system in the second embodiment.
FIGS. 6A and 6B are explanatory diagrams showing the state of data in the second embodiment, in particular, an explanatory diagram when deleting the contents of shared data.
FIG. 7 is a flowchart showing the operation of the system in the second embodiment.
[Explanation of symbols]
1 Client computer
2 network
3 Server computer

Claims (5)

A server computer connected to a plurality of client computers via a network;
The server computer stores physical data of files shared by the plurality of client computers in the server computer, and displays a pointer referring to the physical data on each computer to manage the shared files. A data sharing system to perform,
The server computer is
A pointer generation function for generating another pointer indicating a pointer of a file to be copied as a reference destination when receiving a copy instruction for a predetermined file stored in the server computer from the client computer;
A management table storage function for storing association data between the pointer of the file to be copied and the other pointer in a file management table formed in a server computer;
A pre-change data storage function for temporarily storing and holding data before the change of the physical data when a change occurs in the physical data of the file to be copied ;
Information indicating that the physical data has changed in the client computer corresponding to the other pointer associated with the pointer of the file to be copied after the physical data of the file to be copied has changed A change notification feature that asks if you want to
Association related to the other pointers along with the other pointer data before change of the physical data in from the client computer which has received the notification notified that do not follow the change of the physical data associated to refer directly A data sharing system comprising a physical data migration function for deleting data. When the client computer accesses the other pointer associated with the pointer of the file that is the replication target after the physical data that is the replication target has changed, the change notification function 2. The data sharing system according to claim 1, further comprising a function of notifying information indicating that a change has occurred in physical data of the file to be copied and asking whether or not to follow the change.   The data sharing system according to claim 2, wherein the change of the physical data includes deletion of the physical data. A server computer connected to a plurality of client computers via a network stores physical data of a file shared by the plurality of client computers in the server computer, and pointers that refer to the physical data A data sharing method for managing shared files by displaying them on a computer,
The server computer is
A pointer generation step of generating another pointer indicating the pointer of the file to be copied as a reference destination when receiving a copy instruction of the predetermined file stored in the server computer from the client computer;
A management table storage step in which the server computer stores association data between the pointer of the file to be copied and the other pointer in a file management table formed in the server computer;
When the server computer accesses the other pointer from the client computer, the server computer reads association data from the file management table, and through the pointer of the file to be replicated to which the other pointer is associated. A physical data reference process for referring to the physical data of the file to be copied ;
A pre-change data storage step in which the server computer temporarily stores and holds the data before the change of the physical data when the change occurs in the physical data itself to be replicated , at least after the management table storage step; ,
The server computer, the physical data of the file which is the copy target to the client computer that corresponds to said other pointer associated with the pointer is the copying object after a change in the physical data is generated which is the replicated A change notification step for notifying information that a change has occurred and asking whether to comply with such change;
When the server computer receives a notification from the client computer that has received the notification that the change of the physical data is not followed, the server computer associates the data before the change of the physical data so that the other pointers directly refer to the data, and A data sharing method comprising: a physical data migration step of deleting association data relating to another pointer. Stores physical data of a file shared by a plurality of client computers, and manages a shared file by displaying a pointer referring to the physical data on the client computer, via the network to the plurality of client computers Connected server computer
A pointer generation function for generating another pointer indicating a pointer of a file to be copied as a reference destination when receiving a copy instruction for a predetermined file stored in the server computer from the client computer;
A management table storage function for storing association data between the pointer of the file to be copied and the other pointer in a file management table formed in a server computer;
A pre-change data storage function for temporarily storing and holding data before the change of the physical data when a change occurs in the physical data of the file to be copied ;
Information indicating that the physical data has changed in the client computer corresponding to the other pointer associated with the pointer of the file to be copied after the physical data of the file to be copied has changed A change notification feature that asks if you want to
Association related to the other pointers along with the other pointer data before change of the physical data in from the client computer which has received the notification notified that do not follow the change of the physical data associated to refer directly A data sharing program for realizing a physical data migration function for deleting data.

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