JPH0728759A - Network device using shared resource and method for acquiring right of occupation of shared resource - Google Patents

Abstract

PURPOSE:To reduce the processing work by reducing the traffic intensity on a communication line at the time when each of plural systems connected by the communication line acquires the occupation right for the use of a shared resource. CONSTITUTION:When a system 3A will acquire the occupation right an occupation right request part 4A issues a first occupation right request command in a broadcast form and issues a second occupation right request command in a circular bulletin form after a prescribed time. Another system receives the first occupation right request command to start the preparation processing for prevention of contention access if the shared resource is in course of access, but it receives this command to inhibit the following access if the shared resource is not in course of access. When receiving the second occupation right request command, another system circulates this command to the next system after being set to the state that it can grant the occupation right request. These responses are sent by an occupation right request response part 6A. When the second occupation right request command is returned, an occupation right acquiring part 5A performs the processing for acquisition of the occupation right.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shared resource utilization network device in which a plurality of systems that commonly use resources such as data files are connected by a communication line in a ring shape, and each system is provided. The present invention relates to a shared resource exclusive right acquisition method for acquiring an exclusive right to use a shared resource.

[0002]

2. Description of the Related Art FIG. 5 is a diagram showing a shared resource utilization network device. In FIG. 5, 1 is a communication line, 2 is a shared resource, and 3A to 3F are systems. The plurality of systems 3A to 3F are connected in a ring shape via the communication line 1. Each system accesses the shared resource 2 and uses it. The shared resource 2 is, for example, a customer ledger file accessed from systems of a plurality of branches. When such a ledger file is simultaneously used by a plurality of systems, the data may not be updated correctly or the data may be destroyed. Therefore, a method of giving the exclusive right of the shared resource to only one system at a time is considered so that it is not used simultaneously.

(First Conventional Example) For example, a system that intends to use a shared resource sends a command to acquire an exclusive right to another system via the communication line 1. The other system that receives it writes "accept" if the shared resource is not used, writes "hold" if the shared resource is used, and sends it to another system. The command acts as a circular board. In a ring network, commands are sent in one direction through the ring.

When the system responding "Hold" transfers the exclusive right in view of the priority order of the shared resource use and the like, the system starts a preparatory process so as not to cause any trouble later. Finally, the command returns to the system that issued it, but if any of the answers written there has a "pending", it will issue the command again. Only when all the answers are “accept”, make the system acquire the exclusive right.

(Second Conventional Example) In the first conventional example, as long as there is even one reply of "pending", the command must be issued any number of times, and the respondent responds each time, You have to write the answer. Therefore, since the same operation can be performed many times, the operation is wasteful, the communication amount (traffic amount) flowing through the communication line 1 increases, and the processing efficiency deteriorates.

In order to improve it, the invention disclosed in Japanese Patent Laid-Open No. 63-75864 has been proposed. This will be referred to as a second conventional example. In the second conventional example, when the command issued for the second time is sent, if the acquisition of the exclusive right can be consented, "Accept" is written and sent to the next system, but the preparation process is still completed. If not, wait for completion. When completed, write "accept" and send to the next system. Then, when this command returns to the issuing system, all the answers are “accept”. Therefore, the number of times the command is issued can be limited to two.

[0007]

[Problems to be Solved by the Invention]

(Problem) The second conventional example described above also has a problem that the traffic amount is still large and the processing efficiency is poor. (Explanation of Problems) The command for requesting the acquisition of the exclusive right in the second conventional example has a circulation board format for both the first and second commands. The system that receives the first command writes the approval or suspension and circulates it to the next system. The system that receives the second command does not circulate to the next system while its own system cannot accept it, but circulates it to the next system after it accepts it. Therefore, in the end, each system has to perform the process of writing the answer on the circular board twice, and the process of sending the answer to the next system twice. To send a command to the next system, the communication line 1
Since it is carried out via the, the amount of traffic corresponding to it is generated each time. It is an object of the present invention to solve the above problems, and an object of the present invention is to reduce the processing work and the traffic volume by using only one circulation board type ownership request command. .

[0008]

In order to solve the above problems, according to the present invention, a configuration of each system in a shared resource utilization network device in which a plurality of systems for accessing shared resources are connected in a ring shape through a communication line. An exclusive right requesting unit for issuing a first exclusive right request command in a broadcast format to use the shared resource, and a second exclusive right request command in a circular form after a predetermined time, and its own system. When the second exclusive right request command issued by is returned, the exclusive right acquisition unit that performs the exclusive right acquisition process and the first exclusive right request command issued from another system are shared. A preparatory process for prohibiting access to resources or preventing conflicting access was started and the second ownership request command was received. The was constructed comprising the occupation right request response unit from a state that can accept the exclusive rights requested and sends the occupancy right request command of the second time for the next system.

Further, there is provided a shared resource occupation right acquisition method for each system of a plurality of systems connected in a ring shape through a communication line to acquire an exclusive right to use the shared resource.
The first process in which the system requesting the exclusive right issues the first exclusive right request command in the broadcast format, which transmits the exclusive right request to other systems all at once, and the other process which receives the first exclusive right request command If the system is not accessing the shared resource, the subsequent access is prohibited, and if the system is accessing, the second process of starting the preparation process for avoiding the conflicting access, and the first issue of the exclusive right request command After the third process of issuing the second exclusive right request command in the circular form after a predetermined time, and when the other system receiving the second exclusive right request command becomes ready to accept the exclusive right request. A fourth step of sending the second exclusive right request command to the next system, and a fifth step of acquiring the exclusive right when the second exclusive right request command returns to the issuing system. It was made of the extent.

[0010]

[Operation] When each system of a plurality of systems connected in a ring through a communication line acquires an exclusive right to use the shared resource, the exclusive right request command is issued twice. The first-time possession right request command has a broadcast format in which the intention to acquire the possession right is simultaneously notified to other systems. Other systems that receive this exclusive right request command simply listen to the notification and prepare for it, so there is no need to communicate using the communication line or write the answer in the command. .

The second ownership request command is a circular board type command in which an answer is written and sequentially sent to the next system. The system that receives this does not circulate to the next system until it becomes ready to accept the request for the exclusive right. When the second exclusive right request command returns to the issuing system, the consent of all the other systems has been obtained and the exclusive right is acquired.

In the present invention, of the two times the exclusive right request command, only one is in the circulation board format, so compared with the second conventional example in which the circulation board format exclusive right request command is issued twice. , The amount of traffic is small and the processing work is small.

[0013]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a diagram showing a shared resource utilization network device of the present invention. The reference numerals correspond to those in FIG.
A to 4D are exclusive right requesting units, 5A to 5D are exclusive right acquiring units,
6A to 6D are occupancy right request response units, and 7A to 7D are timers. A plurality of systems are connected in a ring shape via the communication line 1. Since each system has the same configuration, the system 3A will be described as an example.

The exclusive right requesting unit 4A, when an application program in the system 3A wants to use the shared resource 2,
This is the part that issues the exclusive right request command. The exclusive right request command is issued twice in total. The command for requesting the exclusive right for the first time is a command in the broadcast format (broadcast). This is not a circular form, but corresponds to a simultaneous notification to all systems. The second ownership request command has the same circulation board format as the conventional one, and is sent to one of the other systems.

The exclusive right acquisition unit 5A uses its own system 3A.
When the second exclusive right request command issued by the command returns, the exclusive right acquisition processing is performed. After the shared resource 2 has been used, a broadcast-type exclusive right release command is created to inform other systems that the exclusive right is to be released.

The exclusive right request responding section 6A is a part which responds to an exclusive right request command issued by another system when the exclusive right request command is received. That is, when the broadcast-type exclusive right request command is received, if the shared resource 2
If it is not used, subsequent access is prohibited, and if it is used, a preparation process is started to prevent its own system from competing with the system that issued the exclusive right request command. Also, when the second circular board-type ownership request command is received, if the shared resource 2 is not used, immediately write the reply of “accept” and circulate it to the next system, and the preparation process is still completed. If not, write the “accept” answer and circulate to the next system after it is complete.

The timer 7A is for taking an appropriate time from the issuance of the first ownership request command to the issuance of the second ownership request command. This may be configured by hardware or software. Therefore, it is not always necessary to provide a hardware timer as in FIG.

FIG. 2 is a flow chart for explaining the operation of the exclusive right requesting unit. Exclusive right request unit 4A of system 3A
An example will be explained. Step 1 ... It is checked whether an exclusive right request for using the shared resource 2 is issued from the application program in the own system (that is, the system 3A). Step 2 ... When an exclusive right request is made, the exclusive right requesting unit 4A is activated to create a first exclusive right request command. This is to broadcast the intention of requesting the exclusive right to all the systems connected to the communication line 1, and is of a broadcast type.

The format of the exclusive right request command will now be described. FIG. 3 shows the format of the command used in the present invention. In FIG. 3, 8 is a command, 9 is a broadcast bit, 10 is a destination address, 11 is a source address, 12 is a command code, 1
3 is a shared resource ID, and 14 is other. The broadcast bit 9 is a bit for distinguishing whether the code is a broadcast type code. For example, if the value of this bit is "1", it becomes a broadcast format code, and if it is "0", it becomes a code other than that, that is, a code to be sent to a specific destination described in the destination address 10.

In the destination address 10, the address of the system to which this command is delivered when the second ownership request command is created is written. In the issuer address 11, the address given to the system that issued this exclusive right request command is written. In the command code 12, a code that means requesting the exclusive right of the shared resource 2 is written. The shared resource ID 13 includes
The ID (identification number) given to the shared resource 2 is written. The other 14 column is a column for recording other items (for example, the response of each system to the circulation).

Step 3 ... Broadcasting the first exclusive right request command created in Step 2.
The exclusive right request command sent from the system 3A to the communication line 1 is taken in by all the systems,
Are all told that they are requesting the exclusive right. When using the shared resource 2, the receiving system starts a preparatory process for competing with the system 3A to prevent access.

Step 4 ... Set a predetermined time in the timer 7A. This predetermined time defines the time from the issuance of the first ownership request command to the issuance of the second ownership request command. The length of this time is determined based on the time required for each system to complete the preparation process after receiving the first exclusive right request command. Step 5 ... Checks whether a predetermined time has elapsed.

Step 6 ... Create a second exclusive right request command. This time, not the broadcast format but the circulation board format. Therefore, the broadcast bit 9 in FIG.
Is set to a value that does not mean broadcast, and the address of another one system (for example, the system 3B) determined as the destination is written in the destination address 10. The command code 12 and the shared resource ID 13 may be the same as the command created the first time. Such a command is sent to the destination system.

FIG. 4 is a flow chart for explaining the operations of the exclusive right acquisition unit and the exclusive right request response unit. The exclusive right acquisition unit 5A and the exclusive right request response unit 6A of the system 3A will be described as an example. Step 1 ... The exclusive right request response unit 6A checks whether or not the system 3A receives the exclusive right request command from the communication line 1. Step 2 ... Is the received exclusive right request command issued by one's own system (system 3A) and returned once, or is it another system (eg, system 3).
Check if it was issued by B).

Step 3 ... If the command is issued by its own system, it is checked whether the command is a broadcast format ownership request command. If it's a broadcast, you don't need to do anything, as it's the only thing that has notified all the other systems. Step 4 ... If it is not of the broadcast type, it is the second ownership request command. The return of this is nothing but the fact that all the other systems gave an "accept" answer to the request for the exclusive right. Therefore, it is confirmed that the exclusive right has been acquired, and the application program that has issued the exclusive right request is notified of the successful acquisition.

Step 5 ... Shared resource 2 from system 3A
To start access to. Step 6 ... Checks if the access is completed. Step 7 ... Upon completion, a broadcast type exclusive right release command is created. This command also has the same format as that shown in FIG. 3, and the command code 12 is written with a code that means abandonment of the exclusive right. Step 8 ... Broadcasts the exclusive right release command to notify other systems all at once.

Step 9 ... If it is not the command issued by its own system in Step 2, it is checked whether it is of the broadcast format. Step 10 ... If it is a broadcast format,
Since it has been notified that the exclusive right is requested, the system that does not use the shared resource 2 prohibits subsequent access. The system that is using the shared resource 2 starts the preparation process for transferring the exclusive right. And
Wait for the second ownership request command.

Step 11: The fact that the received exclusive right request command from another system is not in the broadcast format means that it is the second exclusive right request command in the circulation board format. If so, step 1
If the preparatory process was started at 0, it is checked whether or not it was completed. When it is finished, even if the exclusive right is transferred to another system, no competitive access is made. If the procedure for prohibiting access is taken in step 10, it is already in a state of not competing for access. Step 12 ... Write "accept" in the second ownership request command and send it to the next system.

[0029]

As described above, according to the present invention, among the exclusive right request commands issued twice, the communication via the communication line is required for each system and the work of writing the reply is required. However, since the circulation board type is only once, compared to the second conventional example in which it is issued twice, the traffic volume and the processing work are reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing a shared resource utilization network device of the present invention.

FIG. 2 is a flowchart illustrating the operation of an exclusive right requesting unit.

FIG. 3 is a diagram showing a format of a command used in the present invention.

FIG. 4 is a flowchart for explaining operations of an exclusive right acquisition unit and an exclusive right request response unit.

FIG. 5 is a diagram showing a shared resource use network device.

[Explanation of symbols]

1 ... communication line, 2 ... shared resource, 3A-3F ... system,
4A to 4D ... Exclusive right request part, 5A to 5D ... Exclusive right acquisition part, 6A to 6D ... Exclusive right request response part, 7A to 7D ... Timer, 8 ... Command, 9 ... Broadcast bit, 10
... destination address, 11 ... issuer address, 12 ... command code, 13 ... shared resource ID, 14 ... other

Claims (2)

[Claims] 1. A shared resource utilization network device comprising a plurality of systems for accessing shared resources connected in a ring shape through a communication line, the configuration of each system comprising:
An exclusive right requesting unit that issues a broadcast-type first exclusive right request command when a user wants to use the shared resource, and a circulation-type second exclusive right request command after a predetermined time, and an own system issue When the second exclusive right request command is returned, the exclusive right acquisition unit that performs the exclusive right acquisition process, and when the first exclusive right request command issued from another system is received, the shared resource is transferred to the shared resource. When the second exclusive right request command is received and the exclusive right request can be accepted, the preparation process for starting the access prohibition or competing access is started to the next system. A shared resource utilization network device, comprising: an exclusive right request responding unit for transmitting a command for exclusive ownership request. 2. In a shared resource occupation right acquisition method for each system of a plurality of systems connected in a ring shape via a communication line to acquire an exclusive right to use a shared resource, the system requesting the exclusive right is occupied. The first process of issuing the first broadcast-type exclusive right request command that simultaneously transmits the right request to the other systems, and the other system receiving the first exclusive right request command is accessing the shared resource. Otherwise, forbid subsequent access,
A second step of starting a preparation process for avoiding competing access during access, and a second process of issuing a second ownership request command in a circular form after a predetermined time from the first issuance of the ownership request command. And the fourth step of sending the second exclusive right request command to the next system when another system that has received the second exclusive right request command is ready to accept the exclusive right request. And a fifth step of acquiring an exclusive right when the second exclusive right request command returns to the issuing system.