JP3533113B2 - Common resource management method and apparatus, and machine-readable recording medium recording program - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a loosely coupled computer system in which a plurality of host computers share an external storage device, and a common external storage device such as a file stored in the external storage device has. The present invention relates to a technology for exclusively controlling resources.

[0002]

2. Description of the Related Art As a technique for exclusively controlling a common resource shared by a plurality of host computers, a common computer in which information indicating a host computer that is using the common resource is registered on the host computer having the common resource. When a resource management table and an operating system unit that performs exclusive control are provided, and when a request to use the common resource is sent from another host computer, the operating system unit refers to the common resource management table and refers to the common resource. A technique of controlling whether or not to permit the use of a computer is conventionally known (for example, Japanese Patent Laid-Open No. 6-198).
No. 58).

In addition to the above, there is conventionally known a technique in which an exclusive control processing device is provided separately from a host computer and the exclusive control processing device is used to perform exclusive control of common resources (for example, Japanese Patent Laid-Open No. 10-91510
Issue).

[0004]

Among the above-mentioned conventional techniques, the technique disclosed in Japanese Patent Laid-Open No. 6-19858 discloses a technique in which use requests from a plurality of host computers are shared by a common resource. Since the processing is performed by the host computer, there is a problem that the load on the host computer having the above-mentioned common resource becomes high.

Further, the conventional technique described in Japanese Patent Application Laid-Open No. 10-91510 requires a special device called an exclusive control processing device used only for performing exclusive control, resulting in an expensive structure. There's a problem.

Further, the above-mentioned two conventional techniques perform exclusive control by using a host computer or an exclusive control processing device having a common resource. There is a problem that computers cannot use common resources.

Therefore, an object of the present invention is to enable exclusive control of common resources without requiring a special device such as an exclusive control processing device and without increasing the load on a specific host computer. At the same time, even if a host computer other than the host computer to which the common resource is allocated fails, another normal host computer can use the common resource.

[0008]

In order to achieve the above object, a common resource management device of the present invention is a loosely coupled computer system in which an external storage device having a plurality of common resources is shared by a plurality of host computers. , Each of the host computers requests a common resource management table that registers the allocation status of each of the common resources, and the common resource management table is not locked when the common resource management table is requested. On condition that the resource management table indicates that the common resource requesting the allocation has not been allocated, the resource allocation table instructs to issue the resource allocation request command including the identifier of the common resource requesting the allocation, and the update permission is given. When given, it relates to the common resource requested for the allocation registered in the common resource management table. Common information allocating means for updating the information indicating that it has been allocated to its own host computer and for issuing a resource allocation completion command, and for issuing the resource allocation request command to the external storage device. When a resource allocation request command including an identifier of a common resource for which allocation is requested is issued, and a resource allocation lock completion command is issued, the host computer that issued the resource allocation request command to the external storage device. Issuing a resource allocation lock completion command including the identifier of the resource allocation completion command, and issuing an instruction to issue the resource allocation completion command, command issuing means for issuing a resource allocation completion command to the external storage device, and an interruption by the resource allocation request command When you accept the The common resource management table in the data is locked so as not to be updated by any means other than its own means, and then a resource allocation lock completion command including the identifier of the host computer that issued the resource allocation request command is issued to the command issuing means. And the information about the common resource requested to be allocated, which is registered in the common resource management table in its own host computer, is updated to indicate that it has been allocated to the host computer that issued the resource allocation request command. However, when the interrupt by the resource allocation lock completion command is accepted, update permission is given to the common resource allocation means on condition that all host computers other than the own host computer have locked the common resource management table. , Resource allocation completion command Interrupt receiving means for releasing the lock of the common resource management table in the host computer when the interrupt is received by the external storage device, and when the external storage device receives the resource allocation request command, the host other than the issuing source When a resource allocation request command interrupt is issued to the computer and the resource allocation lock completion command is accepted, an interrupt is issued to the host computer whose identifier is included in the resource allocation lock completion command by the resource allocation lock completion command. When the resource allocation completion command is received, an interrupting means for generating an interrupt by the resource allocation completion command to a host computer other than the issuing source is provided.

In this configuration, when the common resource allocation request is issued, the common resource allocation means in the requesting host computer does not lock the common resource management table in its own host computer, and the common resource management is performed. Only if the table indicates that the common resource to be allocated is not already allocated (only if another host computer is not trying to receive the common resource and the common resource is not already allocated). ), And issue a resource allocation request command to the external storage device using the command issuing means. In other words, the host computer can determine whether or not it is possible to receive the allocation of the common resource just by referring to the common resource management table provided in the host computer.
It becomes unnecessary to increase the load on a specific host computer or to provide a special device such as an exclusive control processing device.

When the resource allocation request command is issued, the interrupt means in the external storage device generates an interrupt by the resource allocation request command to the host computer other than the request source. Here, the external storage device generally sends an interrupt indicating that when the process according to the read command or the write command is completed to the command issuing source, and the path for sending this interrupt is used. Since the interrupt by the above resource allocation request command can be sent to the host computer, it is not necessary to newly provide a path for sending the interrupt to the host computer.

The interrupt receiving means in the host computer, which has received the interrupt by the resource allocation request command, locks the common resource management table in its own host computer so that other means cannot update the common resource management table. The information about the common resource to be allocated, which is registered in the common resource management table in the own host computer, is updated to indicate that it has been allocated to the requesting host computer. Further, the command issuing means in the host computer issues a resource allocation lock completion command to the external storage device after the interrupt receiving means locks the common resource management table.

As a result, the interrupt means of the external storage device issues an interrupt to the resource allocation request source host computer in response to the resource allocation lock completion command.

The interrupt receiving means in the host computer, which has received the interrupt by the resource allocation lock completion command, becomes the common resource allocating means on condition that all the host computers other than the own host computer have locked the common resource management table. Give update permission. As a result, the common resource allocating means updates the information about the common resource for which the allocation request is made, which is registered in the common resource management table in the own host computer, to the information indicating that it has been allocated to the own host computer.

Further, the common resource management device of the present invention enables each host computer to exchange data via the common resource of the external storage device.
When each of the host computers transfers a common resource assigned to the host computer to another host computer, provided that the common resource management table of the host computer is not locked, When an issue of a resource transfer command including the identifier of the common resource to be transferred and the identifier of the host computer of the transfer destination is instructed, and the update permission is given, the transfer target registered in the common resource management table Common resource transfer means for updating the information about the common resource to indicate that the transfer destination host computer has been allocated, and when the command issuing means is instructed to issue a resource transfer command,
A resource transfer command including the identifier of the common resource to be transferred and the identifier of the host computer of the transfer destination is issued to the external storage device, and when issuing of the resource transfer lock completion command is instructed, the external storage device is sent to the external storage device. In response, a resource transfer lock completion command including the identifier of the host computer that issued the resource transfer command is issued, and when the issue of the resource transfer completion command is instructed, the resource transfer completion command is issued to the external storage device. When the interrupt receiving means has a configuration, when the interrupt by the resource transfer command is accepted, the common resource management table in the own host computer is locked so as not to be updated by any means other than the own means, and then, to the command issuing means. Resource transfer command that includes the identifier of the host computer that issued the resource transfer command. A command to issue a completion command and update the information about the common resource to be transferred, which is registered in the common resource management table in the own host computer, to information indicating that the transfer destination host computer has been allocated. Then, when the interruption by the resource transfer lock completion command is accepted, the update permission is given to the common resource transfer means on condition that all the host computers other than the own host computer have locked the common resource management table, When the interrupt by the resource transfer completion command is accepted, the common resource management table in the host computer is unlocked, and when the interrupt means of the external storage device accepts the resource transfer command, issuance thereof Transfer resources to a host computer other than the original When a resource transfer lock completion command is received, a resource transfer lock completion command interrupt is issued to the host computer whose identifier is included in the resource transfer lock completion command. Is accepted, an interrupt is generated by a resource transfer completion command to a host computer other than the issuing source.

In this configuration, when the common resource assigned to the own host computer is transferred to another host computer, the common resource transfer means in the transfer source host computer uses the common resource in the own host computer. On the condition that the management table is not locked, using the command issuing means to the external storage device,
A resource transfer command including the identifier of the common resource to be transferred and the identifier of the host computer of the transfer destination is issued.

As a result, the interrupt means of the external storage device issues an interrupt by the resource transfer command to the host computer other than the source of the resource transfer command.

The interrupt receiving means in the host computer, which has received the interrupt by the resource transfer command, locks the common resource management table in its own host computer, and prevents other means from updating the common resource management table. The information about the common resource to be allocated, which is registered in the common resource management table in the host computer, is updated to the information indicating that the transfer destination host computer has been allocated. The command issuing means in the host computer issues a resource transfer lock completion command to the external storage device after the interrupt receiving means locks the common resource management table.

As a result, the interrupt means of the external storage device issues an interrupt to the resource transfer source host computer in response to the resource transfer lock completion command.

The interrupt receiving means in the host computer, which has received the interrupt by the resource transfer lock completion command, sends the interrupt request to the common resource transfer means on condition that all host computers other than the own host computer have locked the common resource management table. Give update permission. As a result, the common resource transfer means updates the information about the common resource for which the allocation request is made, which is registered in the common resource management table in the host computer itself, to the information indicating that the host computer has been allocated.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention, in which a plurality of host computers 1-1 to 1-n forming a loosely coupled computer system and each host computer 1-1 to 1-n can be accessed. The external storage device 2 is provided. Each host computer 1-1 to 1-n
Share a plurality of files (not shown) registered in the external storage device 2, which is a common resource. In addition, the host names h1 to h1 are assigned to the respective host computers 1-1 to 1-n.
hn is given.

Next, the host computers 1-1 to 1-n
The configuration of will be described. Each host computer 1
Since -1 to 1-n have the same configuration, the configuration will be described taking the host computer 1-1 as an example.

The host computer 1-1 has a common resource management table 11-1 and a common resource allocation means 12-1.
Common resource releasing means 13-1 and common resource transferring means 1
4-1, an interrupt receiving means 15-1, a command issuing means 16-1, and an access means 17-1.

In the common resource management table 11-1, information indicating the allocation status of each file registered in the external storage device 2, which is a common resource, is registered. FIG. 2 is a diagram showing an example of the contents of the common resource management table 11-1. File names F1 to Fm of all files that are common resources,
The host name of the host computer to which the file is assigned is registered correspondingly. In the example of FIG. 2, files with file names F1 and F2 are assigned to host computers 1-2 and 1-1 with host names h2 and h1, respectively, and files with file names F3 and Fm are assigned to any host computer. It has not been shown.

The common resource allocating means 12-1 receives the common resource from the common resource allocation request source such as the process on the host computer 1-1 when the allocation request including the file name of the file requesting the allocation is notified. A function of instructing the command issuing means 16-1 to issue a resource allocation request command including the file name, provided that the management table 11-1 is not locked and the file has not been allocated; When the interrupt receiving unit 15-1 notifies the update permission, the function of updating the common resource management table 11-1 to display that the file is assigned to the host computer 1-1, and the command issuing unit 16 -1 has a function of giving an instruction to issue a resource allocation completion command.

The common resource release means 13-1 receives the release request including the file name of the file to be released from the common resource release request source such as the process on the host computer 1-1 when the common resource release table 13-1 is issued. Command issuing means 16 on condition that 11-1 is not locked
-1 to the common resource management table 11 when the function of instructing the release of the resource release command including the file name or the update permission from the interrupt receiving means 15-1 is notified.
-1 is updated to display that the file has been released, and a function to instruct the command issuing means 16-1 to issue a resource release completion command.

The common resource transfer means 14-1 transfers from the transfer request source of the common resource such as the process on the host computer 1-1, including the file name of the file to be transferred and the host name of the transfer destination host computer. When the request is notified, the command issuing means 16-1 is provided on condition that the common resource management table 11-1 is not locked.
A function of instructing the issuance of a resource transfer command including the above file name and host name, and interrupt receiving means 15-
1, when the update permission is notified, a function of updating the common resource management table 11-to display that the file is assigned to the transfer destination host computer,
It has a function of instructing the command issuing means 16-1 to issue a resource transfer completion command.

The interrupt receiving means 15-1 has a function of performing interrupt processing according to the type of interrupt from the external storage device 2. In this interrupt processing, the common resource management table 11-1 is locked so as not to be updated by other means, the contents of the common resource management table 11-1 are updated, the common resource allocation means 12-1, Update permission is given to the common resource releasing means 13-1 and the common resource transferring means 14-1, and a resource allocation lock completion command, a resource release lock completion command, and a resource transfer lock completion command are issued to the command issuing means 16-1. Processing for instructing is performed.

The command issuing means 16-1 externally issues the commands instructed to be issued by the common resource allocating means 12-1, the common resource releasing means 13-1, the common resource transferring means 14-1 and the interrupt receiving means 15-1. It has a function of issuing to the storage device 2.

The access means 17-1 has a function of issuing a read / write command to the external storage device 2 and reading / writing data from / to a file stored in the external storage device 2.

The recording medium K1 provided in the host computer 1-1 is a disk, a semiconductor memory, or another recording medium, and a program for causing the host computer 1-1 to function as a part of the common resource management device is recorded. Has been done. This program runs on the host computer 1-
1 and controls the operation of the host computer 1-1, so that the common resource allocating means 12-1 and the common resource releasing means 13-on the host computer 1-1.
1, common resource transfer means 14-1, interrupt receiving means 15
-1, command issuing means 16-1, access means 17-
Achieve 1.

The external storage device 2 has an interrupt transmission means 2
3, interruption means 2 comprising command acceptance means 24
2 and a computer 21 for an external storage device that realizes the file reading / writing means 25. Recording medium K2 provided in the external storage device computer 21
Is a disk, a semiconductor memory, or another recording medium, in which a program for causing the external storage device computer 21 to function as a part of the common resource management device is recorded. This program is read by the external storage device computer 21, and by controlling the operation of the external storage device computer 21, the interrupt transmission means 23, the command reception means 24, the file read / write means are provided on the external storage device computer 21. Achieve 25.

The file reading / writing means 25 is the access means 1 in each of the host computers 1-1 to 1-n.
A function of reading and writing a file stored in the external storage device 2 according to the read command and the write command from 7-1 to 17-n, and a command issuing source every time the processing according to the read command and the write command is completed Has a function of generating an interrupt in the host computer.
The external storage device generally has such a function.

The command receiving means 24 has a function of receiving various commands issued from the host computers 1-1 to 1-n, a function of determining a host computer as an interrupt destination based on the type and content of the received command, and , A function of instructing the interrupt transmission means 23 to the interrupt destination host computer, and a function of storing the received command in a command storage unit (not shown) provided on a storage medium (not shown) of the external storage device 2. Alternatively, the address information indicating the storage location of the command is sent to the interrupt sending means 23.
It has a function to notify. Here, the above-mentioned command storage unit has an area for each of the host computers 1-1 to 1-n, and when the command reception unit 24 stores the command in the command storage unit, Stored in the area corresponding to the issuing host computer.

The interrupt transmitting means 23 has a function of generating an interrupt including the address information notified from the command receiving means 24 to the host computer of the interrupt destination specified by the command receiving means 24.

FIG. 3 shows each host computer 1-1 to 1-
common resource allocation means 12-1 to 12- included in n
4 is a flow chart showing a processing example of n, FIG. 4 shows a common resource releasing means 13-1 provided in each host computer 1-1 to 1-n.
13 to 13-n, and FIG. 5 is a flowchart showing a processing example of the common resource transfer means 14-1 to 14-n included in each host computer 1-1 to 1-n, FIG. 7
8 is a flow chart showing a processing example of command issuing means 16-1 to 16-n provided in each host computer 1-1 to 1-n, and FIG. 8 is an interrupt provided in each host computer 1-1 to 1-n. FIG. 9 is a flow chart showing a processing example of interrupt processing performed when the receiving means 15-1 to 15-n receive an interrupt by a resource allocation request command. FIG. 10 is a flow chart showing a processing example of interrupt processing performed when an interrupt is received. FIG.
1 to 15-n is a flow chart showing an example of processing of interrupt processing performed when the interrupt by the resource allocation completion command is received, FIG. 11 is performed when the interrupt receiving means 15-1 to 15-n receive the interrupt by the resource release command FIG. 12 is a flow chart showing a processing example of interrupt processing, FIG. 12 is a flow chart showing a processing example of interrupt processing performed when the interrupt receiving means 15-1 to 15-n receive an interrupt due to a resource release lock completion command, and FIG. 13 is an interrupt receiving means. 15-1 ~
FIG. 1 is a flowchart showing an example of an interrupt process performed when 15-n receives an interrupt due to a resource release completion command.
4 is a flow chart showing a processing example of interrupt processing performed when the interrupt receiving means 15-1 to 15-n receive the interrupt by the resource transfer command, and FIG.
-1 to 15-n is a flow chart showing an example of an interrupt process performed when the interrupt by the resource transfer lock completion command is received, and FIG. 16 is an interrupt receiving means 15-1 to 15-n.
FIG. 17 is a flow chart showing an example of a process of an interrupt process performed when a resource transfer completion command receives an interrupt, FIG. 17 is a flow diagram showing an example of the process of the command accepting unit 24, and FIG. 19 is an operation explanatory view at the time of file allocation, FIG. 20 is an operation explanatory view at the time of file release, and FIG. 21 is an operation explanatory view at the time of file transfer. The operation of this embodiment will be described below with reference to the drawings.

First, the operation at the time of allocating the common resource will be described by taking the case where the host computer 1-1 requests the allocation of the file having the file name F3 as an example.

When the process in the host computer 1-1 requests the allocation of the file with the file name F3, it issues a resource allocation request including the file name F3 to the common resource allocation means 12-1.

As a result, the common resource allocation means 12-
As shown in the flow chart of FIG. 3, 1 checks whether the common resource management table 11-1 is locked by the interrupt receiving means 15-1 (A1). If it is locked, it waits for the lock to be released. If it is not locked, it immediately refers to the common resource management table 11-1 to check whether or not the file with the file name F3 has already been allocated ( A2).

If the request has been allocated, it notifies the requesting process that it cannot be allocated (A8). On the other hand, if it has not been assigned, the command issuing means 1
The file name F3 is notified to 6-1 (A3).

When the command issuing means 16-1 is notified of the file name F3 by the resource allocating means 12-1, as shown in the flow chart of FIG. 6, the resource allocation including the file name F3 and the issuer's host name h1. A request command is issued to the external storage device 2 (YES in D1, D2).

When the command accepting means 24 in the external storage device 2 accepts the resource allocation request command from the host computer 1-1, as shown in the flowchart of FIG. 17, the interrupt destination is determined based on the type and content of the command. The host computer of (N1). In this example,
Since the type of command is a resource allocation request command, the command receiving means 24 sets the host computers 1-2 to 1-n other than the host computer 1-1 that issued the resource allocation request command as the interrupt destination.

After that, the command receiving means 24 stores the resource allocation request command in the area allocated to the host computer 1-1 in the command storage section (N2), and the address information indicating the storage position and N1.
The host names h2 to hn of the host computers 1-2 to 1-n obtained in step 3 are passed to the interrupt transmitting means 23 (N3).

As a result, the interrupt transmitting means 23, as shown in the flow chart of FIG.
An interrupt including the address information passed from the command receiving means 24 is generated for .about.1-n (P1).

When the interrupt receiving means 15-2 to 15-n in the host computers 1-2 to 1-n receive the interrupt, the interrupt receiving means 15-2 to 15-n start the interrupt process, and the external device indicated by the address information included in the interrupt. The command stored in the area on the storage device 2 is acquired, and it is recognized that the interrupt is due to the resource allocation request command. Thereby, the interrupt receiving means 15-2 to 15-15
As shown in the flowchart of FIG. 8, -n is the common resource management table 11-2 in the host computer 1-2 to 1-n.
11-n are locked so that they cannot be updated by any means other than the own means 15-2 to 15-n (E1). After that, the interrupt receiving means 15-2 to 15-n have the command issuing means 1
6-2 to 16-n are notified of the completion of the lock at the time of resource allocation and the host name h1 of the source of the resource allocation request command, and the common resource management table 11-2.
The assigned host name for the file name F3 registered in 11 to 11-n is updated to the host name h1 (E2.
E3).

The command issuing means 16-2 to 16-n are
When the lock completion at the time of resource allocation is notified, as shown in the flowchart of FIG. 7, a resource allocation lock completion command including the host name h1 of the source of the resource allocation request command is issued to the external storage device 2. (D13 is YE
S, D14).

The command receiving means 24 performs the processing of the flow chart of FIG. 17 every time it receives the resource allocation lock completion command from each of the command issuing means 16-2 to 16-n. In the case of this example, in N1, since the command type is the resource allocation lock completion command and the host name h1 is included, the host computer 1-1 is the interrupt destination host computer. In N2, the received resource allocation lock completion command is stored in the area corresponding to the host computer that issued the command in the command storage unit, and in N3, the address information indicating the storage location of the command and the interrupt destination are stored. Host name h1
And are passed to the interrupt transmitting means 23.

The interrupt issuing means 23 generates an interrupt including the above address information to the host computer 1-1 every time the address information and the host name h1 are passed from the command receiving means 24 (FIG. 18, P1). .

The interrupt receiving means 15-1 in the host computer 1-1 receives an interrupt from the external storage device 2,
When it is recognized that the interrupt is the resource allocation lock completion command based on the contents of the command storage unit, the interrupt process shown in the flowchart of FIG. 9 is performed.

In F1, the number of receptions i of the interrupt due to the resource allocation lock completion command (which is 0 in the initial state) is incremented by 1, and in the next F2, the number of receptions i is (n-
1), that is, whether all the host computers 1-2 to 1-n other than the host computer 1-1 have completely locked the common resource management tables 11-2 to 11-n. Then, if the number of receptions i is not (n-1), the processing is ended, and if it is (n-1), after giving the update permission to the common resource allocation unit 12-1. (F3), the number of receptions i is set to “0” (F
4).

When the update permission is given, the common resource allocating means 12-1 registers the file name F registered in the common resource management table 11-1 as shown in the flowchart of FIG.
The assigned host name corresponding to No. 3 is changed to the host name h1 of the own host computer 1-1 (A4, A5). Through the above processing, each of the common resource management tables 11-1 to 11-n
The contents of will be the same. After that, the common resource allocation unit 12-1 notifies the command issuing unit 16-1 of the completion of the resource allocation processing and also notifies the process of the resource allocation request source that the file with the file name F3 is permitted to be used (A6). , A7).

When the command issuing means 16-1 is notified by the common resource allocating means 12-1 that the allocation processing is completed, the command issuing means 16-1 issues the host name h
A resource allocation completion command including 1 is issued to the external storage device 2 (D3, D4).

When the command accepting means 24 in the external storage device 2 accepts the resource allocation completion command from the host computer 1-1, it carries out the processing shown in the flowchart of FIG. In the case of this example, in N1, the type of command is a resource allocation completion command, so the host computers 1-2 to 1-n other than the issuing source are set as the interrupt destination host computers. At N2, the received resource allocation completion command is stored in the area corresponding to the host computer 1-1 in the command storage unit, and N
In 3, the interrupt sending means 23 sets the address information indicating the storage location of the command and the host names h2 to hn of the interrupt destination.
Pass to.

As a result, the interrupt transmitting means 23 generates an interrupt containing the address information of the command storage position to the host computers 1-2 to 1-n (P1 in FIG. 18).

When the interrupt receiving means 15-2 to 15-n in the host computers 1-2 to 1-n recognize that the interrupt is due to the resource allocation completion command based on the contents of the command storage section, As shown in the flowchart of FIG. 10, the common resource management tables 11-2 to 11-n in the host computers 1-2 to 1-n are unlocked (G1).

Next, the operation at the time of releasing the common resource will be described by taking as an example the case where the host computer 1-1 releases the file with the file name F1 assigned to its own host.

When releasing the file having the file name F1, the process on the host computer 1-1 issues a releasing request including the file name F1 to the common resource releasing means 13-1.

As a result, the common resource releasing means 13-1
Checks whether the common resource management table 11-1 is locked by the interrupt receiving means 15-1 as shown in the flowchart of FIG. 4 (B1), and unlocks if locked. Then, if the file is not locked, the common resource management table 11-1 is immediately referenced to check whether or not the file with the file name F1 has been assigned to the host computer 1-1 (B2).

If the request has not been allocated, the requesting process is notified that the process cannot be released (B
8). On the other hand, if the file has been allocated, the command issuing means 16-1 is notified of the file name F1 of the file to be released (B3).

As a result, the command issuing means 16-1
Issues a resource release command including the file name F1 and the issuing source host name h1 to the external storage device 2 as shown in the flowchart of FIG. 6 (YES in D5, D6).

When the command receiving means 24 in the external storage device 2 receives the resource release command from the host computer 1-1, as shown in the flowchart of FIG. 17, the interrupt destination is determined based on the type and content of the received command. The host computer is requested (N1). In this example,
Since the command type is the resource release command, the command receiving means 24 sets all the host computers 1-2 to 1-n other than the command issuing source as interrupt destinations.

After that, the command receiving means 24 stores the received resource release command in the area allocated to the host computer 1-1 in the command storing section, and obtains the address information indicating the area and N1. The host names h2 to hn of the interrupt destination are passed to the interrupt transmitting means 23 (N2, N3).

As a result, the interrupt transmitting means 23, as shown in the flow chart of FIG.
An interrupt including the address information of the area in which the resource release command is stored is generated for ~ 1-n (P
1).

When the interrupt receiving means 15-2 to 15-n in each of the host computers 1-2 to 1-n recognize that the interrupt is due to the resource release command based on the contents of the command storage section, 11, the common resource management tables 11-2 to 11-n are locked and the common resource management table 11-2 is locked by another means.
Prevent ~ 11-n from being updated (H1). After that, the interrupt receiving means 15-2 to 15-n issue a command to the command issuing means 16-2 to 16-n to complete the lock at the time of releasing the resource and issue the host name h1 of the resource releasing command.
Of the common resource management tables 11-2 to 11-1
The assigned host name corresponding to the file name F1 registered in 1-n is updated to NULL, and it is displayed that the file with the file name F1 has been released (H2, H3).

The command issuing means 16-2 to 16-n are
When the lock completion at the time of resource release is notified, as shown in the flowchart of FIG. 7, a resource release lock completion command including the host name h1 of the source of the resource release command is issued to the external storage device 2 ( D15 is YES, D16).

The command receiving means 24 in the external storage device 2 performs the processing shown in the flowchart of FIG. 17 every time it receives a resource release lock completion command from each of the host computers 1-2 to 1-n. In the case of this example, since the command type is the resource release lock completion command and includes the host name h1, the host computer of the interrupt destination is the host computer 1-1 in N1. Further, in N2, the resource release lock completion command is stored in the area corresponding to the host computer that issued the command in the command storage unit, and in N3, the interrupt destination host name h1 and the address indicating the storage location of the command. Information is passed to the interrupt transmitting means 23.

As a result, the interrupt transmitting means 23, as shown in the flow chart of FIG.
, An interrupt including address information indicating the storage location of the command is generated (P1).

When the interrupt receiving means 15-1 in the host computer 1-1 recognizes that the received interrupt is the interrupt due to the resource release lock completion command, based on the contents of the command storage section, as shown in FIG. Then, it is determined whether the number j of interrupts by the received resource release lock completion command has become (n-1) (I
1, I2). If it is not (n-1), the processing is terminated, and if it is (n-1), the common resource releasing means 13-1 is given an update permission and then received. The number of times j is set to "0" (I3, I4).

When the update permission is given, the common resource releasing means 13-1 sets the assigned host name for the file name F1 registered in the common resource management table 11-1 to NULL as shown in the flowchart of FIG. Update to (B
4, B5). After that, the common resource releasing unit 13-1 notifies the command issuing unit 16-1 of the completion of the resource releasing process and the release requesting process of the releasing completion (B6, B7).

When the command issuing means 16-1 is informed of the completion of the resource releasing process, the command issuing means 16-1
A resource release completion command including the issuer's host name h1
It is issued to the external storage device 2 (D7, D8).

When the command receiving means 24 in the external storage device 2 receives the resource release completion command from the host computer 1-1, it carries out the processing shown in the flowchart of FIG. In the case of this example, in N1, the type of command is the resource release completion command, so that the host computers 1-2 to 1-n other than the issuing source are set as the interrupt destination host computers. In N2, the received resource release completion command is stored in the area corresponding to the host computer 1-1 in the command storage unit. In N3, the address information indicating the storage position of the command and the host name h2 of the interrupt destination are stored. and hn are passed to the interrupt transmitting means 23.

As a result, the interrupt transmitting means 23 issues an interrupt containing the address information of the command storage position to the host computers 1-2 to 1-n (P1 in FIG. 18).

The interrupt receiving means 15-2 to 15-n in the host computers 1-2 to 1-n recognize that the interrupt is due to the resource release completion command based on the contents of the command storage section. As shown in the flow chart of FIG. 13, the common resource management tables 11-2 to 11-n in the host computers 1-2 to 1-n are unlocked (J1).

Next, the operation at the time of transferring the common resource will be described by taking as an example the case where the host computer 1-1 transfers the file having the file name F1 allocated to its own host to the host computer 1-n. The transfer of the common resource is used, for example, when transferring data.

When transferring data to the host computer 1-n, the process on the host computer 1-1 writes the transfer data to the file with the file name F1 using the access means 17-1 and then transfers the common resource. File name F1 of the file to be transferred to the means 14-1
And the host name hn of the destination host computer 1-n
Issue a transfer request including.

As a result, the common resource transfer means 14-1
5 checks whether the common resource management table 11-1 is locked by the interrupt receiving means 15-1 as shown in the flowchart of FIG. 5 (C1), and if it is locked, it is unlocked. Then, if the file is not locked, the common resource management table 11-1 is immediately referenced to check whether or not the file with the file name F1 has been assigned to the host computer 1-1 (C2).

If not already assigned, the requesting process is notified that the process is not transferable (C
8). On the other hand, if the file has been allocated, the command issuing means 16-1 is notified of the file name F1 of the file to be transferred and the host name hn of the transfer destination (C3).

As a result, the command issuing means 16-1
Is the file name F to be transferred, as shown in the flowchart of FIG.
1. A resource transfer command including the transfer destination host name hn and the command issuing source host name h1 is issued to the external storage device 2 (YES in D9, D10).

When the command receiving means 24 in the external storage device 2 receives the resource transfer command from the host computer 1-1, as shown in the flowchart of FIG. 17, the interrupt destination is determined based on the type and content of the received command. The host computer is requested (N1). In this example,
Since the type of command is a resource transfer command, the command receiving means 24 sets all host computers 1-2 to 1-n other than the command issuing source as interrupt destinations.

After that, the command receiving means 24 stores the received resource transfer command in the area allocated to the host computer 1-1 in the command storing section, and obtains the address information indicating the area and N1. The host names h2 to hn of the interrupt destination are passed to the interrupt transmitting means 23 (N2, N3).

As a result, the interrupt transmitting means 23, as shown in the flow chart of FIG.
An interrupt including the address information of the area in which the resource transfer command is stored is generated for ~ 1-n (P
1).

When the interrupt receiving means 15-2 to 15-n in each of the host computers 1-2 to 1-n recognize that the interrupt is due to the resource transfer command, based on the contents of the command storage section, As shown in the flowchart of FIG. 14, the common resource management tables 11-2 to 11-n are locked and the common resource management table 11-is locked by another means.
2-11-n are not updated (K1). After that, the interrupt receiving means 15-2 to 15-n notify the command issuing means 16-2 to 16-n of the lock completion at the time of resource transfer and the host name h1 of the source of the resource transfer command, respectively. Common resource management table 11
The assigned host name corresponding to the file name F1 registered in −2 to 11-n is updated to the transferee host name hn (K2, K3).

The command issuing means 16-2 to 16-n are
When the lock completion at the time of resource transfer is notified, as shown in the flowchart of FIG. 7, a resource transfer lock completion command including the host name h1 of the source of the resource transfer command is issued to the external storage device 2 ( D17 is YES, D18).

The command receiving means 24 in the external storage device 2 performs the processing shown in the flowchart of FIG. 17 every time it receives the resource transfer lock completion command from each of the host computers 1-2 to 1-n. In the case of this example, since the command type is the resource transfer lock completion command and includes the host name h1, the host computer of the interruption destination is the host computer 1-1 in N1. In N2, the resource transfer lock completion command is stored in the area corresponding to the host computer that issued the command in the command storage unit. In N3, the host name h1 of the interrupt destination and the address information indicating the storage location of the command are stored. It is passed to the interrupt transmitting means 23.

As a result, the interrupt issuing means 23, as shown in the flow chart of FIG.
, An interrupt including address information indicating the storage location of the command is generated (P1).

When the interrupt receiving means 15-1 in the host computer 1-1 recognizes that the received interrupt is the interrupt by the resource transfer lock completion command, as shown in FIG. 15, the received resource transfer lock completion command is received. It is determined whether or not the number k of interrupts by (n-1) has become (L1, L2). If it is not (n-1), the process is terminated, and if it is (n-1), the common resource transfer unit 14-1 is given an update permission, and then received. The number k is set to “0” (L3, L
4).

When the update permission is given, the common resource transfer means 14-1 determines the assigned host name for the file name F1 registered in the common resource management table 11-1 as shown in the flowchart of FIG. It is updated to the host name hn of the transfer destination host computer 1-n (C4, C5).
After that, the common resource transfer unit 14-1 notifies the command issuing unit 16-1 of the completion of the resource transfer process, and also notifies the release requesting process of the transfer completion (C
6, C7).

When the command issuing means 16-1 is notified of the completion of the resource transfer processing, as shown in the flow chart of FIG.
A resource transfer completion command including the issuer's host name h1
Issued to the external storage device 2 (YES in D11, D
12).

When the command receiving means 24 in the external storage device 2 receives the resource transfer completion command from the host computer 1-1, it carries out the processing shown in the flowchart of FIG. In the case of this example, in the case of N1, since the command type is the resource transfer completion command in N1, the host computers 1-2 to 1-n other than the issuing source are set as the interrupt destination host computers. In N2, the received resource transfer completion command is stored in the command storage unit
Store in the area corresponding to the host computer 1-1,
At N3, the address information indicating the storage location of the command and the interrupt destination host names h2 to hn are sent to the interrupt issuing means 2
Pass to 3.

As a result, the interrupt issuing means 23 issues an interrupt containing address information indicating the storage location of the command to the host computers 1-2 to 1-n (P1 in FIG. 18).

When the interrupt receiving means 15-2 to 15-n in the host computers 1-2 to 1-n recognize that the interrupt is due to the resource transfer completion command,
As shown in the flowchart of FIG.
Common resource management tables 11-2 to 11-n in 1 to n
Unlock (M1).

By the above processing, the file with the file name F1 is assigned to the host computer 1-n, so the process in the transfer destination host computer 1-n uses the access means 17-n. , The transfer data from the host computer 1-1 stored in the file F1 can be read.

[0093]

The first effect of the present invention is that exclusive control of common resources can be performed without providing a special device such as an exclusive control processing device or increasing the load on a specific host computer. The point is that you can. The reason is that each host computer is provided with a common resource management table so that each host computer can independently determine whether or not it can receive a common resource allocation.
This is because the contents of the common resource management table are matched and the information for locking the common resource management table is exchanged between the host computers via the external storage device.

The second effect of the present invention is that data can be exchanged between a plurality of host computers without requiring a special device. The reason is that the common resource such as a file in which the transfer data assigned to the data transfer source is written can be rewritten to the host computer of the data transfer destination simply by rewriting the contents of the common resource management table provided in each host computer. This is because they can be transferred.

The third effect of the present invention is that the risk that all host computers cannot use common resources can be extremely reduced. The reason is that each host computer has its own common resource management table, and it is possible to determine whether or not each host computer can be individually assigned a common resource. However, if a failure occurs in the host computer to which the common resource is assigned, the above common resource cannot be used in other normal host computers, but it is assigned to the failed host computer. By using the existing technology for releasing the common resource, the common resource can be used even when the host computer to which the common resource is allocated fails.

[Brief description of drawings]

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

FIG. 2 is a diagram showing an example of contents of common resource management tables 11-1 to 11-n.

FIG. 3 is a flowchart showing a processing example of common resource allocation means 12-1 to 12-n.

FIG. 4 is a flowchart showing a processing example of common resource releasing means 13-1 to 13-n.

FIG. 5 is a flowchart showing a processing example of common resource transfer means 14-1 to 14-n.

FIG. 6 is a flowchart showing a processing example of command issuing means 16-1 to 16-n.

FIG. 7 is a flowchart showing a processing example of command issuing means 16-1 to 16-n.

FIG. 8 is a flowchart showing a processing example of interrupt processing performed when the interrupt receiving means 15-1 to 15-n receive an interrupt according to a resource allocation request command.

FIG. 9 is a flowchart showing an example of an interrupt process performed when the interrupt receiving units 15-1 to 15-n receive an interrupt due to a resource allocation lock completion command.

FIG. 10 is a flowchart showing a processing example of interrupt processing performed when the interrupt receiving means 15-1 to 15-n receive an interrupt due to a resource allocation completion command.

FIG. 11 is a flowchart showing a processing example of interrupt processing performed when the interrupt receiving means 15-1 to 15-n receive an interrupt by a resource release command.

FIG. 12 is a flowchart showing a processing example of interrupt processing performed when the interrupt receiving means 15-1 to 15-n receive an interrupt due to a resource release lock completion command.

FIG. 13 is a flowchart showing a processing example of interrupt processing performed when the interrupt receiving means 15-1 to 15-n receive an interrupt due to a resource release completion command.

FIG. 14 is a flowchart showing a processing example of interrupt processing performed when the interrupt receiving means 15-1 to 15-n receive an interrupt by a resource transfer command.

FIG. 15 is a flowchart showing an example of an interrupt process performed when the interrupt receiving means 15-1 to 15-n receive an interrupt due to a resource transfer lock completion command.

FIG. 16 is a flowchart showing a processing example of interrupt processing performed when the interrupt receiving means 15-1 to 15-n receive an interrupt due to a resource transfer completion command.

FIG. 17 is a flowchart showing a processing example of the command reception means 24.

FIG. 18 is a flowchart showing a processing example of the interrupt transmitting means 23.

FIG. 19 is an explanatory diagram of an operation when allocating a file.

FIG. 20 is an explanatory diagram of an operation when releasing a file.

FIG. 21 is an explanatory diagram of an operation when transferring a file.

[Explanation of symbols] 1-1 to 1-n ... Host computer 11-1, 11-2 ... Common resource management table 12-1, 12-2 ... Common resource allocating means 13-1, 13-2 ... Common resource releasing means 14-1, 14-2 ... Common resource transfer means 15-1, 15-2 ... Interrupt receiving means 16-1, 16-2 ... Command issuing means 17-1, 17-2 ... Access means 2 ... External storage device 21 ... Computer for external storage device 22 ... Interrupting means 23 ... Interrupt transmission means 24 ... Command accepting means 25 ... File reading / writing means K1, K2 ... Recording medium

─────────────────────────────────────────────────── --Continued from the front page (56) References JP-A-6-19858 (JP, A) JP-A-10-91510 (JP, A) JP-A-7-219792 (JP, A) JP-A-8- 166929 (JP, A) JP-A-10-240696 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G06F 9/46 G06F 15/177 G06F 12/00

Claims (7)

(57) [Claims] 1. In a loosely coupled computer system in which a plurality of host computers share an external storage device having a plurality of common resources, each host computer requests its allocation of the common resources. , The common resource management table for registering the allocation status of each common resource is not locked, and the common resource management table indicates that the common resource requesting allocation has not been allocated yet. On the condition that the resource allocation request command including a common resource identifier requesting allocation to the external storage device is issued, the external storage device accepts the resource allocation request command, An interrupt is issued to a host computer other than the command issuer. Each host computer that has received the interrupt by the resource allocation request command, the interrupt process,
A common resource management table in its own host computer is locked so as not to be updated except by the interrupt processing, and a resource allocation lock completion command including the identifier of the host computer that issued the resource allocation request command to the external storage device. And the information about the common resource requested to be allocated, which is registered in the common resource management table in the own host computer, is updated to information indicating that the host computer that issued the resource allocation request command has been allocated. The external storage device, every time the resource allocation lock completion command is received, generates an interrupt to the host computer whose identifier is included in the resource allocation lock completion command, and interrupts the resource allocation lock completion command. Receiving The attached host computer assigns the allocation request registered in the common resource management table provided in the own host computer on condition that all host computers other than the own host computer have completed locking the common resource management table. After updating the information for the common resource that has been allocated to the host computer, a resource allocation completion command is issued to the external storage device, and the external storage device receives the resource allocation completion command. By so doing, an interrupt is generated to a host computer other than its issuing source, and each host computer that accepts the interrupt by the resource allocation completion command unlocks the common resource management table in its own host computer. Common resources to Management method. 2. The common resource management method according to claim 1, wherein each of the host computers has a common resource management table provided in its own host computer when releasing the common resource allocated to the own host computer. Issue a resource release command including an identifier of a common resource to be released to the external storage device, if the external storage device receives the resource release command, Each host computer that has generated an interrupt to a host computer other than the issuer of the release command and has received the interrupt by the resource release command uses the interrupt process to set the common resource management table in the host computer other than the interrupt process. Locked so that it is not updated, and The resource release lock completion command including the identifier of the host computer that issued the resource release command to the device, and the common resource requested to be released that is registered in the common resource management table in the host computer. The information is updated to indicate that the information has been released, and the external storage device interrupts the host computer whose identifier is included in the resource release lock completion command every time the resource release lock completion command is received. The host computer that has received the interrupt due to the resource release lock completion command has generated the common resource provided to the host computer, provided that all host computers other than the host computer have locked the common resource management table. The above registered in the management table After updating the information about the common resource requested to be released to one indicating that it has been released, a resource release completion command is issued to the external storage device, and the external storage device receives the resource release completion command. The host computer other than the issuing source generates an interrupt, and each host computer that accepts the interrupt by the resource release completion command unlocks the common resource management table in its own host computer. Common resource management method. 3. The common resource management method according to claim 2, wherein each host computer is provided with its own host computer when the common resource assigned to the host computer is transferred to another host computer. On condition that the common resource management table is not locked, a resource transfer command including the identifier of the common resource to be transferred and the identifier of the transfer destination host computer is issued to the external storage device, The external storage device generates an interrupt to the host computer other than the source of the resource transfer command by receiving the resource transfer command, and each host computer that receives the interrupt by the resource transfer command executes the interrupt process. , In front of the common resource management table of the local host computer It is locked so that it is not updated except by interrupt processing, and a resource transfer lock completion command including the identifier of the host computer that issued the resource transfer command is issued to the external storage device, and a common command in its own host computer is issued. The information about the common resource to be transferred, which is registered in the resource management table, is updated to information indicating that the transfer destination host computer has been allocated, and the external storage device receives the resource transfer lock completion command. For each time, an interrupt is generated to the host computer whose identifier is included in the resource transfer lock completion command, and the host computer that receives the interrupt by the resource transfer lock completion command is all host computers other than the own host computer. Is the common resource management table Indicating that the information about the common resource to be transferred, which is registered in the common resource management table of the own host computer, has been assigned to the transfer destination host computer on condition that the lock is locked. After the update, the resource transfer completion command is issued to the external storage device, and the external storage device accepts the resource transfer completion command to generate an interrupt to a host computer other than the issuing source. A common resource management method, wherein each host computer that has received an interrupt due to the resource transfer completion command unlocks a common resource management table included in the host computer. 4. A loosely-coupled computer system in which an external storage device having a plurality of common resources is shared by a plurality of host computers, wherein each of the host computers registers a common resource allocation status. A resource management table and, when requesting allocation of the common resource, the common resource management table is not locked, and the common resource management table indicates that the common resource requesting the allocation has not been allocated. On the condition that the resource allocation request command including the identifier of the common resource for which allocation is requested is issued, and when the update permission is given, the allocation registered in the common resource management table is requested. Updated the information about common resources to indicate that it was assigned to the local host computer And a resource allocation request command including an identifier of a common resource requesting allocation to the external storage device when a resource allocation request command is issued. Is issued and issuance of the resource allocation lock completion command is instructed,
When the resource allocation lock completion command including the identifier of the host computer that issued the resource allocation request command is issued to the external storage device and the issuing of the resource allocation completion command is instructed, resources are issued to the external storage device. When the command issuing means for issuing the allocation completion command and the interrupt by the resource allocation request command are accepted, after locking the common resource management table in the own host computer so that it is not updated by other means,
The command issuing means is instructed to issue a resource allocation lock completion command including the identifier of the host computer that issued the resource allocation request command, and the allocation request registered in the common resource management table in the host computer is requested. The information about the common resource is updated to the information indicating that the resource allocation request command has been allocated to the host computer that issued the resource, and when an interrupt due to the resource allocation lock completion command is accepted, all hosts other than the own host computer On condition that the computer has locked the common resource management table, the common resource allocation means gives update permission, and when an interrupt by the resource allocation completion command is accepted, the common resource management table in the own host computer And an interrupt receiving unit that releases the resource, when the external storage device receives the resource allocation request command, generates an interrupt by the resource allocation request command to a host computer other than the issuing source, When the allocation lock completion command is accepted, an interrupt is issued by the resource allocation lock completion command to the host computer whose identifier is included in the resource allocation lock completion command, and when the resource allocation completion command is accepted, issuance thereof A common resource management device comprising interrupt means for generating an interrupt by a resource allocation completion command to a host computer other than the original one. 5. The common resource management device according to claim 4, wherein when each of the host computers requests release of a common resource assigned to its own host computer, the common resource management table is locked. If the release permission is given and the release permission is given, the release request registered in the common resource management table is issued when the update release is given, on condition that the release request is not issued. A common resource releasing unit that updates the information about the resource to that indicating that it has been released is provided, and when the command issuing unit is instructed to issue a resource releasing command, the command is released to the external storage device. Issue a resource release command containing the identifier of the requested common resource,
When the issuance of the resource release lock completion command is instructed,
A resource release lock completion command including the identifier of the host computer that issued the resource release command is issued to the external storage device, and when the issue of the resource release completion command is instructed, the resource is released to the external storage device. When a completion command is issued, the interrupt receiving unit locks the common resource management table in the own host computer so as not to be updated by any means other than the own device when the interrupt receiving unit receives the interrupt by the resource releasing command, and then, The command issuing means is instructed to issue a resource release lock completion command including the identifier of the host computer that issued the resource release command, and the release requested common registered in the common resource management table in the host computer Update information about resources to indicate release and When the interrupt by the source release lock completion command is accepted, on condition that all the host computers other than the own host computer have locked the common resource management table,
When the update permission is given to the common resource release means and the interrupt by the resource release completion command is accepted, the lock of the common resource management table in the own host computer is released, and the interrupt of the external storage device is performed. When the means receives the resource release command, an interrupt by the resource release command is issued to the host computer other than the issuing source, and when the resource release lock completion command is received, the resource release lock completion command includes an identifier. When a resource release lock completion command is issued to an existing host computer and the resource release completion command is accepted, an interrupt is issued to the host computer other than the issuing host computer by the resource release completion command. Characterized by having a configuration Common resource management device. 6. The common resource management device according to claim 5, wherein when each of the host computers transfers a common resource assigned to the host computer to another host computer, the host computer On condition that the provided common resource management table is not locked, the issue of a resource transfer command including the identifier of the common resource to be transferred and the host computer of the transfer destination is instructed, and the update permission is given. And a common resource transfer means for updating the information about the common resource to be transferred, which is registered in the common resource management table, to information indicating that the common computer has been allocated to the transfer destination host computer, and When the command issuing means is instructed to issue a resource transfer command, the external storage device To the external storage device when a resource transfer command including the identifier of the common resource to be transferred and the identifier of the host computer of the transfer destination is issued to the external storage device. A resource transfer lock completion command including the identifier of the host computer that issued the command is issued, and when a resource transfer completion command is issued, a resource transfer completion command is issued to the external storage device. When the interrupt receiving unit receives an interrupt by the resource transfer command, the common resource management table in the host computer is locked so that it is not updated by any other unit, and then the resource transfer command is issued to the command issuing unit. Resource transfer lock completion command including the identifier of the host computer that issued the Is issued and the information about the common resource that is the transfer target registered in the common resource management table in the host computer is updated to the information indicating that the transfer destination host computer has been allocated. When the interrupt by the transfer lock completion command is accepted, update permission is given to the common resource transfer means on condition that all host computers other than the own host computer lock the common resource management table, and the resource transfer is completed. When the interruption by the command is accepted, the lock of the common resource management table in the host computer is released, and when the interruption means of the external storage device accepts the resource transfer command, it is not the source of the issue. Resource transfer command allocation to the host computer When the resource transfer lock completion command is received, the resource transfer lock completion command is interrupted to the host computer whose identifier is included in the resource transfer lock completion command, and the resource transfer completion command is received. A common resource management device having a configuration in which an interrupt is issued by a resource transfer completion command to a host computer other than the issuing source when the shared resource management command is issued. 7. A host computer in a loosely coupled computer system sharing an external storage device having a plurality of common resources, the host computer being provided with the host computer when requesting allocation of the common resource. The common resource management table that manages the resource allocation status is not locked,
In addition, on condition that the common resource management table indicates that the common resource requesting the allocation has not been allocated, an instruction to issue a resource allocation request command including an identifier of the common resource requesting allocation is issued, When the update permission is given, the information about the common resource requested to be allocated, which is registered in the common resource management table, is updated to the information indicating that the host computer has been allocated and the resource allocation completion command is issued. A resource allocation request command including a common resource identifier requesting allocation to the external storage device, when a resource allocation request command is issued, and a resource allocation lock completion command is issued. Is issued,
When the resource allocation lock completion command including the identifier of the host computer that issued the resource allocation request command is issued to the external storage device and the issuing of the resource allocation completion command is instructed, resources are issued to the external storage device. A command issuing means for issuing an allocation completion command, when an interrupt by a resource allocation request command is accepted, after locking the common resource management table in the own host computer so that it is not updated by other means,
The command issuing means is instructed to issue a resource allocation lock completion command including the identifier of the host computer that issued the resource allocation request command, and the allocation request registered in the common resource management table in the host computer is requested. The information about the common resource is updated to the information indicating that the resource allocation request command has been allocated to the host computer that issued the resource, and when an interrupt due to the resource allocation lock completion command is accepted, all hosts other than the own host computer On condition that the computer has locked the common resource management table, the common resource allocation means gives update permission, and when an interrupt by the resource allocation completion command is accepted, the common resource management table in the own host computer Interrupt receiving means for releasing the click,
And a program for causing the computer for the external storage device to receive the resource allocation request command, generate an interrupt due to the resource allocation request command to a host computer other than the issuing source, and allocate the resource. When the lock completion command is accepted, an interrupt is issued by the resource allocation lock completion command to the host computer whose identifier is included in the resource allocation lock completion command, and when the resource allocation completion command is accepted, its issuer And a program for causing a host computer other than the above to function as an interrupting means for generating an interrupt by a resource allocation completion command, and a machine-readable recording medium having the program recorded therein.