Data access system for server in distributed computer system

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention is a distributed system of a computer system including a power system that preferentially accesses a light-load server computer in a system having a plurality of data server computers in a distributed system and a client computer that accesses the data. Regarding the data access method of the server in.

【0002】

[Conventional technology]

Conventionally, when the client computer X or Y of the client computer group accesses the server computer group having shared data between a plurality of server computers A and B as shown in FIG. 13, the server computer The server computer that accesses data from among multiple server computers depending on the operation mode was specified as, for example, server computer A. In this case, in order to access regardless of the load of the server computer, multiple client computers X and Y simultaneously access data to the specific server computer A, and the load is concentrated on the specific server computer A and the entire system is used. It was a factor of the decrease in response.

【0003】

[Problems to be Solved by the Invention]

According to the present invention, when a client computer accesses data from a server computer, it easily recognizes a server computer having a light load among a plurality of server computers, and accesses the server computer to obtain a high response. When multiple clients access the data of the server computer at the same time, the server computer that is requested to access is distributed, so the load of the server computer is distributed, including the one for the power system. The purpose is to maintain the responsiveness of the computer system as a whole, and to improve the reliability by performing high-speed backup processing in the event of a failure by multiplexing communication lines using this method.

【0004】

[Means for solving problems]

In order to achieve the above object, the data access method of the server in the distributed computer system according to [claim 1] of the present invention uses shared data arranged in a memory device or a disk device that can be shared by a plurality of computers. In a distributed system consisting of a data server computer consisting of multiple computers and a client computer that accesses the data, the lightest load among the multiple server computers that exist when the client computer refers to the shared data of the server computer. It is configured to make a data transmission request to a server computer.

【0005】

The actual data access is performed by the server data access process of the client computer and the shared data access process of the server computer. When the client computer refers to the shared data, the light load server computer acquisition process makes a data reference request to all the server computers at the same time, and each server computer that receives the request returns the response by the data access response process. The requesting client computer that receives it transfers data from the server computer that responded earliest and refers to the data.

【0006】

As a result, the server computer that returned the response earliest is judged to be the server computer with the lightest load among all the server computers, and the client computer makes a data transmission request to this server computer and transmits the data to be referred to. get. As a result, when the client computer refers to the data of the server computer, the responsiveness of the server computer is improved because the data transmission request is made to the light load server computer.

【0007】

The server data access method in the distributed computer system according to [claim 2] of the present invention is a data server computer composed of a plurality of computers having shared data arranged in a memory device or a disk device that can be shared by a plurality of computers. In a distributed system consisting of client computers that access the data, when the client computer updates the shared data of the server computer, the update data is sent to the server computer, which has the lightest load among the multiple server computers. Configured to update shared data.

【0008】

When the client computer updates the shared data, the light load server computer acquisition process makes a data update request to all the server computers at the same time, and each server computer that receives the request returns the response by the data access response process. The requesting client computer that receives it sends the update data to the server computer that responded the earliest, and updates the shared data by a specific server computer.

【0009】

As a result, the server computer that returned the response earliest is judged to be the server computer with the lightest load among all the server computers, and the responsiveness of the server computer is improved by making a data update request to the server computer. At the same time, when a plurality of client computers simultaneously request data update to the server computer, the load on the server computer is distributed.

【0010】

The server data access method in the distributed computer system according to [claim 3] of the present invention is a distributed system composed of a plurality of data server computers and a client computer that accesses the data, in which the client computer operates the server computer. In order to identify the server computer that matches the conditions when accessing in a limited manner, it is judged by the response from each server computer to the access request from the client computer, and the data to be accessed in this case is determined by multiple server computers. If owned by, it is configured to access the server computer, which has the lightest load.

【0011】

When a client computer requests data access from a server computer under certain conditions, the condition is given and a data access request is made to all server computers, and each server computer that receives the request matches the condition. The result is returned to the requesting client computer. The client computer that made the data access request receives the response data and determines the server computer that performs the data access.

【0012】

This simplifies the process because the requesting computer does not need to know in advance which server computer matches the conditions to be accessed or which server computer owns the requested data. In both cases, when there are responses from a plurality of server computers, it is possible to access at high speed by performing data access to the server having the lightest load among them.

【0013】

The server data access method in the distributed computer system according to [claim 4] of the present invention is a data server computer composed of a plurality of computers having shared data arranged in a memory device or a disk device that can be shared by a plurality of computers. In a distributed system consisting of client computers that access the data, when the client computer refers to the shared data of the server computer or when the client computer updates the shared data of the server computer, a specific client computer is the server. When there are multiple accessible server computers when accessing a large amount of computer data, it is configured to efficiently operate multiple server computers in parallel by dividing the data into multiple computers and requesting the server computers. To.

【0014】

Further, in a distributed system composed of a plurality of data server computers and a client computer that accesses the data, when the client computer accesses by limiting the operation mode of the server computer, a specific client computer performs the data of the server computer. When there are a plurality of accessible server computers in the case of accessing a large amount of data, the data is divided into a plurality of data and requested to the server computers so that the plurality of server computers can be efficiently operated in parallel.

【0015】

When a client computer requires a large amount of data access from a server computer and there are a plurality of accessible server computers, the request data is divided into a plurality of pieces and a data access request is made to the plurality of server computers.

【0016】

This is effective when the client computer accesses a large amount of data from the server computer and there are multiple accessible server computers. In this case, the data access is given priority to the light load server computer. This makes it possible to perform the data access required by the client computer at high speed.

【0017】

The server data access method in the distributed computer system according to the present invention [claim 5] is the distributed computer system according to the above [claim 1] or [claim 2] or [claim 3] or [claim 4]. If the server computer becomes unable to process due to a failure while the client computer is accessing a specific server computer due to the data access method of the server in It is configured to make an access request from the middle of the data and back it up.

【0018】

When it becomes impossible to continue processing due to a failure such as when the server computer goes down during data access of the server computer because the client computer that accesses the data knows the accessible server computer in advance. , Request access to other healthy server computers only for data that has not been accessed.

【0019】

As a result, when the client computer that accesses the data cannot continue the processing due to a failure such as the server computer going down during the data access processing of the server computer, the processing is performed by accessing the sound server computer from the middle of the processing. The processing time can be shortened without the need to redo the operation, and the backup processing can be speeded up. Further, this method is particularly effective when different server computers own the same data and the client computer does not update the data of the server computer.

【0020】

The data access method of the server in the distributed computer system according to [Claim 6] of the present invention is the distributed computer system according to the above [Claim 1] or [Claim 2] or [Claim 3] or [Claim 4]. In the data access method of the server in the above, in the distributed computer system using the multiplexed communication line, the data access is performed by preferentially using the communication line having the lightest load among the plurality of multiplexed lines. It is configured to access data at higher speed and distribute the load on the line.

【0021】

When the client computer accesses the server computer, the client computer sends a data access request to the server computer, and the server computer that receives the access request multiplexes the return of the data access availability response to the requesting client computer. The data is returned to multiple communication lines at the same time, and the data of the server computer is accessed using the line received earliest by the requesting client computer.

【0022】

As a result, high-speed data access is possible by performing data access using the line that received the data earlier, and as a result, performing server data access using the light load line.

【0023】

The server data access method in the distributed computer system according to [Claim 7] of the present invention is a data access request in the server data access method in the distributed computer system according to [Claim 5] or [Claim 6] above. The original client computer is configured to recognize the light load server computer and the light load line in advance.

【0024】

By the client computer of the data access request source knowing the server computer that can be backed up and the communication line in advance, the request source client computer knows the light load computer and the light load line when accessing the data of the server computer. At the same time, the server computer that can be backed up and the communication line that can be backed up can be recognized, so recovery is performed in the event of a failure.

【0025】

As a result, it is possible to know in advance which server computer owns the data requested by the client computer and which communication line can be communicated with, so that the server computer during data access or In the event of a failure in the communication line, it is possible to make a quick backup and improve the reliability.

【0026】

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 is a configuration diagram which is a basis of the present invention, and in particular, illustrates the outline of the means according to [Claim 1] and [Claim 2].

【0027】

When client computer X or Y accesses shared data shared between multiple server computers A and B, it can be accessed by requesting either server computer A or B, so multiple servers. Since it is clear that it is more efficient to transfer data than a computer with a light load among the computers, a communication request is made to a plurality of server computers and a response from the server computer is waited for.

【0028】

The server computer that receives the communication request returns a response to the requesting client computer. When the requesting client computer receives a response from a plurality of server computers, it is configured to make a data access request to the server computer that returned the response earliest.

【0029】

The present invention, for example, in a computer system that monitors an electric power system, stores online data such as a system status in shared data of a server computer from an external system, and is suitable when the client computer accesses the data.

【0030】

FIG. 2 is a configuration for explaining the means according to [Claim 1] and [Claim 2] of the present invention in more detail, and is a server computer group 1 using server computer A10, server computer B11, and shared data 100 shared by them. It is composed of a plurality of computers by the client computer group 2 by the client computer X20 and the client computer Y21.

【0031】

In addition, each computer of the server computer group 1 and the client computer group 2 is connected by a LAN line 600, and access between the computers is possible. Since the shared data 100 is shared by the server computer A10 and the server computer B11, when the client computer X or Y refers to the data, the request is made to any computer A or B belonging to the server computer group 1. Will be done.

【0032】

In the invention according to [claim 1], when the client computer refers to the shared data 100 of the server computer, which of the plurality of server computers belonging to the server computer group 1 accesses the shared data 100 to the client computer. In order to determine whether to transmit data to each of the client computers X and Y, the light load server computer determination processing means C10 for determining which server computer to access the data to, and for each server computer , The data access response processing means S10 that responds to the access request from the client computer is arranged.

【0033】

The actual data access is performed by the server data access processing means C20 of the client computer and the shared data access processing means S20 of the server computer. When the client computer refers to the shared data 100, the light load server computer acquisition processing means C10 simultaneously requests data reference to all server computers, and each server computer that receives the request returns a response by the data access response processing means S10. .. The requesting client computer that receives it transfers data from the server computer that responded earliest and refers to the data.

【0034】

Next, the processing flow of the server data access method in the distributed computer system according to [Claim 1] of the present invention will be described with reference to FIG. The client calculator starts processing in step 31. At the same time, the server computer also starts processing in step 40. In the client computer, if a data access factor of the server computer occurs in step 32, the data access request is transmitted to all the server computers in step 33, and the response reception from the server computer is waited in step 34.

【0035】

Since the server computer is in the state of waiting for the access request from the client computer in step 41, when the access request from the client computer is received in step 42, the response is returned to the requesting client computer in step 43, and step 44 Waits for a data transfer request from the client computer.

【0036】

When the client computer receives the response from the server computer in step 35, it determines whether there is a response from the server computer in step 36, and if there is a response from the server computer, in step 37, the earliest response is given. Send a data transfer request to the returning server.

【0037】

In step 45, the server computer determines whether or not there is a data transmission request from the client computer. If there is a data transmission request, the shared data is transmitted to the requesting client computer in step 46. The client computer receives data from the server computer in step 38, and ends the process in step 39.

【0038】

In this way, when data is referenced, the responsiveness of the server computer is improved because processing is prioritized for the light-load server computer, and access is made when multiple client computers refer to the shared data 100 at the same time. Since the required server computers are distributed, it is an effective means for load distribution of server computers.

【0039】

The invention according to [Claim 2] is a method for updating shared data from a client computer, and will be similarly described with reference to FIG. Since the shared data 100 is shared by the server computer A10 and the server computer B11, when the client computer updates the data, a request is made to any computer belonging to the server computer group 1.

【0040】

In order for the client computer to determine to which server computer the update data is sent to update the shared data 100 among the plurality of server computers belonging to the server computer group 1, each client computer X20 and Y21 is light. The load server computer determination processing means C10 is arranged, and the data access response processing means S10 is arranged in each of the server computers A10 and A11.

【0041】

The actual data update is performed by the server data access processing means C20 of the client computer and the shared data access processing means S20 of the server computer. When the client computer updates the shared data 100, the light load server computer determination processing means C10 makes a data update request to all the server computers at the same time, and each server computer that receives the request returns a response by the data access response processing means S10. To do.

【0042】

The requesting client computer that receives it sends the update data to the server computer that responded the earliest, and updates the shared data 100 by a specific server computer.

【0043】

Next, for example, in a computer system that monitors the power system, the database of power system equipment is saved in the shared data of the server computer, so this method is applied when updating the data from the client computer X20 due to equipment maintenance, etc. The case where this is done will be described below.

【0044】

The client computer X needs to make an access request to the server computer A10 or the server computer B11 in order to update the shared data 100 of the server computers A and B. In this case, a data access request is broadcast to the server computer A10 and the server computer B11, and each server computer that receives the data access request returns a response to the requesting client computer X20.

【0045】

At this time, if the client X20 receives the response from the server computer A10 first, it is determined that the server computer A10 is the lightest load computer among the server computers, and the data of the equipment database to be changed for this server computer is input. Send and update the database.

【0046】

In this way, in the server data access method in this method, the processing speed can be increased in order to preferentially make data update requests to the server computer, which has a light load, and the shared data 100 can be shared by multiple client computers at the same time. Since the server computers that are requested to be accessed when updated are distributed, the responsiveness of the entire system will be improved.

【0047】

FIG. 4 is a schematic diagram illustrating a server data access method in the distributed computer system according to [claim 3] of the present invention, in which response conditions are added to access requests from a client computer to a plurality of server computers A and B. However, it is a method of accessing the server computer with the lightest load among the computers that own the data to be accessed.

【0048】

FIG. 5 is a configuration of one example for explaining the server data access method according to [Claim 3] of the present invention in more detail. The server computer A10, the data 200 owned by the computer, the server computer B11, and the computer thereof It is composed of a plurality of server computers and client computers, which are composed of a server computer group 1 composed of owned data 300 and a client computer group 2 composed of a client computer X20 and a client computer Y21.

【0049】

When the client computer X20 or Y21 accesses the data of the server computer, it makes a request to all the server computers by adding a condition such as "access only when the computer mode of the server computer matches the requesting client computer". The data access response processing means S10 returns a response to the requesting client computer as a result of whether or not each server computer that received it matches the conditions.

【0050】

The requesting client computer identifies the server computer that accesses the data based on the result of the response. In this case, when there are a plurality of server computers that match the requirements, data access is performed to the server computer that responds earlier.

【0051】

The process of identifying the server computer accessed by the client computer is performed by the data access server determination processing means C10 and the data access response processing means S10, and the processing of performing the actual data access is performed by the server data access processing means C20 and the data access processing means S20. This function is realized by.

【0052】

FIG. 6 is a configuration of another example for explaining the data access method of the server according to [Claim 3] of the present invention, and is composed of a plurality of server computers A and B and client computers X and Y. Each server computer owns two types of databases, database 400 and database 500, and switches the database according to the computer mode or the like.

【0053】

In this case, the database 400 owned by each server computer is the same, and is equivalent to a plurality of servers for the purpose of load distribution and the like, and the same applies to the database 500.

【0054】

For example, it is assumed that the server computer has an operation mode of "normal mode" and "test mode" and is always operating in either mode. The database 400 is used in the normal mode, and the database is used in the test mode. It shall work using 500.

【0055】

In this case, when the client computer X20 accesses the "data in use in normal mode" of the server computer, it is broadcast by adding conditions such as "access the data in use in normal mode" to all server computers. Each server computer that sends a data access request and receives it returns a response to the requesting client computer X20 only when it is using data that matches the data access conditions.

【0056】

If there are multiple server computers that match the data access conditions, the database used in normal mode is accessed for the server computer that returned earlier because multiple responses are returned.

【0057】

Therefore, if the database 400 is changed to use the test mode and the database 500 is used as the regular mode due to data maintenance of the server computer, the client computer that accesses the data can access it normally without knowing the situation. Therefore, the processing can be simplified.

【0058】

Next, the processing flow of the server data access method in the distributed computer system according to [Claim 3] of the present invention will be described with reference to FIG. 7.

【0059】

The client calculator starts processing in step 71. At the same time, the server computer also starts the process in step 81. In the client computer, if a data access factor of the server computer occurs in step 72, a data access request is transmitted to all the server computers with access conditions in step 73, and a response reception from the server computer is waited in step 74.

【0060】

Since the server computer is in the state of waiting for the access request from the client computer in step 81, when the access request from the client computer is received in step 82, it is determined in step 87 whether or not the access conditions are matched, and they match. If so, the process proceeds to step 83, and if they do not match, the process returns to step 81. In step 83, only the server computer that matches the conditions returns a response to the requesting client computer, and in step 84, the state waits for a data transfer request from the client computer.

【0061】

In the client computer, when the response from the server computer is received in step 75, it is determined in step 76 whether or not there is a response from the server computer, and if there is a response from the server computer, the response is made earliest in step 77. Send a data transfer request to the returned server computer.

【0062】

In step 85, the server computer determines whether or not there is a data transmission request from the client computer. If there is a data transmission request, the shared data is transmitted to the requesting client computer in step 86. The client computer receives data from the server computer in step 78, and ends the process in step 79.

【0063】

In this way, the server data access method in this method does not require complicated access processing of the client computer that responds to changes in the operating mode of the server computer, so processing speed is increased and software development costs are reduced. It also leads to quality improvement.

【0064】

Further, when a plurality of server computers own the data requested by the client computer, high-speed data access is possible in order to access the server computer having the lightest load among them.

【0065】

The data access method of the server in the distributed computer system according to [Claim 4] of the present invention is the data access method according to [Claim 1] or [Claim 2] or [Claim 3], and the client computer is the data access method. When it is necessary to access a large amount of data to a server computer, if there are multiple accessible server computers in parallel, the request data is divided into multiple pieces, and the data is distributed to multiple server computers in each division unit. It makes an access request.

【0066】

FIG. 8A shows a schematic diagram of the data access method of the server computer according to [Claim 4] of the present invention. This method is significant when a plurality of server computers own the data required by the client computer in a computer system composed of a system as shown in FIG. 2 or FIG.

【0067】

For example, if the data of the server computer that the client computer wants to access is 10 Mbytes, this can be divided into 10 in 1 Mbyte units to access multiple server computers at the same time, or as shown in Fig. 8 (B). This is achieved by dividing the data into 0.5 Mbytes and 1 Mbytes, and accessing one part to the server computer A and the other part to the server computer B in 1 Mbyte units.

【0068】

In this case, by making the data access request in units of 1 Mbyte, if each server computer is operating with almost the same load, the access request from the client computer is shared and processed by a plurality of server computers. In addition, by performing the judgment processing of the light load server computer for each request in units of 1 Mbyte, it is possible to make an access request according to the load status of each server computer.

【0069】

Next, the processing flow of the client computer in the server data access method according to [Claim 4] of the present invention will be described with reference to FIG.

【0070】

When an access request is made to the server computer in step 91, it is determined in step 92 whether or not there is a response from the plurality of servers, and if there is a response, the process proceeds to step 93, and the data to be accessed is divided into a plurality of parts. In the next step 94, the data is accessed in the divided data units by the method already described.

【0071】

Next, in step 95, it is determined whether or not the access of all the data is completed, and if it is completed, the process proceeds to the next process. If it is not completed, the process returns to step 94 and the data access is repeated.

【0072】

In this method, requests from client computers can be processed at high speed by operating a plurality of server computers in parallel. In addition, this makes it possible to perform processing without concentrating the load on a specific server computer, so that the load of the server computer is distributed and the responsiveness of the entire system is improved.

【0073】

The server data access method in the distributed computer system according to [Claim 5] of the present invention is the data access method according to [Claim 1] or [Claim 2] or [Claim 3] or [Claim 4]. Therefore, if the client computer cannot continue processing due to a server computer failure while accessing the data of the server computer, only the data for which access has not been completed will be sent to other healthy server computers. A backup is requested from the middle.

【0074】

FIG. 10 shows a schematic diagram of the data access method of the server computer according to [Claim 5] of the present invention. And this method is applied to the sound server computer B when the client computer fails in the server computer A while the client computer is accessing the data of the server computer in the computer system composed of the system as shown in Fig. 2 or Fig. 6. To make an alternative request.

【0075】

That is, since the client computer that accesses the data recognizes the accessible server computer in advance, if there is a sound server computer other than the server computer in which the failure has occurred, the client computer requests access to the server computer. Then, for example, when the same data exists in a plurality of server computers, when the client computer refers to the data, the same data can be obtained regardless of which server computer accesses the data.

【0076】

In this method, when a failure occurs in the server computer being processed, data access request can be made to another healthy server computer from the middle of the data without interrupting the data access processing being processed. It is possible to build a system that is resistant to failures by enabling high-speed recovery processing without having to start over.

【0077】

The data access method of the server in the distributed computer system according to [Claim 6] of the present invention is the data access method according to [Claim 1] or [Claim 2], or [Claim 3] or [Claim 4]. When the client computer accesses the server computer, the server computer that receives the access request from the client computer simultaneously returns the access response to the requesting client computer to a plurality of multiplexed communication lines. , The data access of the server computer is performed using the line received by the requesting client computer earliest.

【0078】

FIG. 11 shows a schematic diagram of the data access method of the server computer according to [Claim 6] of the present invention. In this method, in a computer system composed of a system as shown in Fig. 2 or Fig. 6, the LAN line 600 connecting each computer is multiplexed, and the multiple lines are efficiently used to access the data of the server computer. Is to do.

【0079】

In this case, the line speed of the multiplexed LAN shall have the same specifications. For example, each computer is connected by a duplicate LAN line, and data transfer between the client computer and the server computer uses two LANs for different purposes, and the load on each LAN line depends on the situation. When it fluctuates, the client computer makes a data access request to the server computer, and the line side where the response arrives earlier is used as the light load line, and the line is preferentially used, so that the server computer-client uses the light load line. Data access between computers will be performed.

【0080】

By accessing the data using the light load line in this way, the responsiveness of the server computer as seen from the client computer can be improved, so that the processing speed can be increased and the load distribution of the LAN line can be performed efficiently. Since it is possible, it is possible to prevent a line neck from occurring without concentrating processing on a specific line.

【0081】

The server data access method in the distributed computer system according to [Claim 7] of the present invention is the data access method according to [Claim 5] and [Claim 6], and is a server computer to which a client computer can access data. And the LAN line is grasped in advance, and backup is performed in the event of a failure.

【0082】

FIG. 12 shows a schematic diagram of the data access method of the server computer according to [Claim 7] of the present invention. And this method is returned from the server computer when the client computer accesses the data of the server computer in the computer system composed of the same system as the embodiment of [Claim 5] and [Claim 6]. By recognizing the access response and the available side of the duplicated LAN line, backup is performed in the event of a failure.

【0083】

That is, when the client computer makes a data access request for the server, a response is returned from the accessible server computer. This response is received from both the duplicated LAN lines, and all the responses from the accessible server computer are received. This makes it possible to know the light load computer and the light load line when accessing the data of the server computer, but it is also possible to recognize the server computer and the communication line that can be backed up at the same time.

【0084】

In this way, if the server computer during data access goes down due to a failure, the server computer is switched to another accessible server computer to continue the process. If an abnormality in the communication line is detected, the line is switched to a backup-capable line and backup processing is performed. This enables quick backup in the event of a computer failure, and makes it possible to build a system that is resistant to failures.

【0085】

[Effect of the invention]

As described above, in the present invention, in a system having a plurality of data server computers in a distributed system and a client computer that accesses the data, the response of the entire system is performed by preferentially accessing the lightly loaded server computer. It is possible to improve the responsiveness of the server computer by ensuring the performance and preferentially using the light load communication line, and thereby it is possible to distribute the load of the server computer.

【0086】

In addition, since quick backup can be performed even when a failure occurs due to multiplexing of communication lines or the like, high speed and reliability can be improved when data is accessed between distributed computers.

[Simple explanation of drawings]

[Figure 1]

It is a block diagram which is the basis of this invention, and in particular, is the schematic diagram of the means which concerns on [Claim 1] and [Claim 2].

[Figure 2]

A more detailed block diagram of the means according to [Claim 1] and [Claim 2] of the present invention.

[Fig. 3]

The processing flow of the data access method of the server in the distributed computer system according to [Claim 1] of the present invention.

[Fig. 4]

The schematic diagram explaining the data access method of the server in the distributed computer system which concerns on [Claim 3] of this invention.

[Fig. 5]

The block diagram of one example explaining the data access method of the server which concerns on [Claim 3] of this invention in more detail.

[Fig. 6]

The block diagram of another example explaining the data access method of the server which concerns on [Claim 3] of this invention.

[Fig. 7]

The processing flow of the data access method of the server in the distributed computer system which concerns on [Claim 3] of this invention.

[Fig. 8]

The schematic diagram of the data access method of the server computer which concerns on [Claim 4] of this invention.

[Fig. 9]

The processing flow of the client computer in the data access method of the server according to [Claim 4] of the present invention.

[Fig. 10]

The schematic diagram of the data access method of the server computer which concerns on [Claim 5] of this invention.

[Fig. 11]

The schematic diagram of the data access method of the server computer which concerns on [Claim 6] of this invention.

[Fig. 12]

The schematic diagram of the data access method of the server computer which concerns on [Claim 7] of this invention.

[Fig. 13]

The schematic diagram explaining the data access method of the server in the conventional distributed computer system.

[Explanation of symbols]

1 Server computer group consisting of multiple server computers 2 Client computer group consisting of multiple client computers 10 Server computer A 11 Server computer B 20 Client Calculator X 21 Client computer Y 100 Data shared by server computer A and server computer 200 Data owned by server computer A 300 Data owned by server computer B 400 Data owned by server computers A and B Data owned by 500 server computers A and B 600 LAN line C10 Light load server Computer determination processing means C20 server data access processing means S10 Data access response processing means S20 Data access processing means