JPH0659917A - Exclusive control system for shared resources - Google Patents

Abstract

PURPOSE:To effectively utilize shared resources so as to improve the processing efficiency of respective processes by permitting a succeeding process to use the resources at the time of requiring the use of the resources only for their reference when a preceding process is being used in an updating shared mode. CONSTITUTION:In the case of requiring the use of a resource X, a process A outputs the request to a resource managing part 10. The name of the resource and a mode to be used, i.e., an exclusive using mode, an updating shared mode or a reference-only mode, are specified as the contents of the request. At the time of receiving the request, the managing part 10 refers to a using resource storing part 102 and checkes whether the resource concerned is being used or not. When the resource is in use, whether the resource is in the reference-only mode or not is checked. When the resource is in the reference-only mode, the request mode is changed to the updating shared mode and the use of the resource X is permitted. Simultaneously the name of the resource X and its using mode are stored in the storing part 102.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exclusive control system for shared resources whose contents can be updated.

[0002]

2. Description of the Related Art Generally, in a processing system having a CPU, a memory, and an external storage device, resources whose contents can be updated may be shared by processes.

The resources mentioned here are, for example, files in the operating system, documents in the document processing system, design drawings in the design support system such as CAD, and design drawings in the software development support system. There are various things such as specification information depending on the purpose of the system.

A process is a series of processes that use resources in a computer, for example. It includes a process in which a person intervenes to perform processing interactively, a process activated by a person, and an autonomous process without human intervention.

There are the following two methods for sharing such resources.

The first is the sharing of resources only by reference. In this case, as long as the system capacity is not exceeded, multiple processes can share and refer to resources at any timing. Since the referenced resource is not updated, it is not necessary to prohibit the use when sharing.

The second is sharing involving resource update. In this case, it is possible that multiple processes try to update one resource at the same time, so it may be necessary to prohibit the use when sharing.

As this prohibition method, for example, "program product VOS3 / ES supervisor macro" is used.
(Hitachi Manual 8091-3-015-30)
There is a method shown in “2.5.1 ENQ macro” of. In this prohibition method, two modes, that is, an exclusive mode and a shared mode, are provided for use of resources, and the prohibition of use at the time of sharing is determined by the combination of these two modes.

FIG. 9 shows a matrix of such 2 mode × 2 mode exclusive control.

In this exclusive control method, generally, the use is started in the exclusive mode when it is desired to use it for the purpose of updating resources, and the use is started in the shared mode when it is desired to use it only for referring to resources.

According to FIG. 9, for example, when the process A first starts using the resource X in the exclusive mode, the subsequent process B is not permitted to use the resource X until the process A finishes using the resource X. . In addition, process A is resource X
If the process A is started in the shared mode, the subsequent process B can start using the resource X only in the shared mode even if the process A does not finish using the process.

[0012]

However, in the exclusive control method shown by the matrix in FIG. 9, when the process A starts using the resource X in the exclusive mode, until the process A finishes using it. The following process B is not permitted even if it wants to use it only for reference.

Therefore, assuming that the resource X is a document, for example, if the process A starts using the document in the exclusive mode for the purpose of editing the document, the subsequent process B is not permitted to read the document. In particular, process A
Editing for a long time will result in all other processes, including process B, being forbidden to read the document for a long time.

In this case, if a process other than the process A desires to read the document, a method of contacting the process A and having the use temporarily suspended is used.
Although such a problem is solved, there is a high possibility that the processing of the main process A is frequently interrupted.
A new problem arises that the processing efficiency of the situation decreases.
In addition, especially when the process A is a process in which a person intervenes and performs processing interactively, the interruption of the person's thinking is moved, and in this case also the processing efficiency is lowered.

In any case, there is a problem that the processing efficiency of both the preceding process A and the succeeding process B is lowered, and the shared resources cannot be effectively used.

An object of the present invention is to provide an exclusive control system for shared resources, which can effectively utilize the shared resources and efficiently advance the processing of each process.

[0017]

In order to achieve the above object, the present invention uses a monopolized mode for a preceding process as a mode that can be designated when starting to use a resource whose content can be updated by a plurality of processes. The use mode and update sharing mode, and the subsequent process has the exclusive use mode, the update sharing mode, and the reference only mode, and by combining these modes, the resources used by the preceding process in the exclusive use mode are The use by the process is prohibited, and the resource that is being used by the preceding process in the update sharing mode is allowed only by the following process in the reference only mode.

Alternatively, each of the preceding process and the succeeding process has an exclusive use mode, an update sharing mode, and a reference only mode, and the combination of these modes causes the preceding process to use the resources being used in the exclusive use mode. Prohibits the subsequent process from using the resource, and the preceding process uses the resource that is being used in the update sharing mode only for the subsequent process in the reference-only mode. The resource only allows subsequent processes to be used in the reference-only mode or the update sharing mode.

In summary, when sharing the resource whose contents can be updated, even if the preceding process is in the state of being used for the purpose of updating, the succeeding process is allowed to use for the purpose of reference only. A reference-only mode is provided.

[0020]

According to the above means, when the subsequent process desires to use the resource only for reference, if the preceding process is in the update sharing mode, the resource is permitted to be used.

As a result, any process can utilize its resources and efficiently proceed with its own processing.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to illustrated embodiments.

FIG. 3 is a block diagram showing an embodiment of a processing system to which the present invention is applied.

The processing system 1 of this embodiment includes a CPU,
It is configured as, for example, a computer or a word processor having a memory and an external storage device, and has a resource management unit 10 inside.

The processing system 1 may be a system composed of one processing device and one or more terminal devices connected thereto, or a system composed of a plurality of processing devices connected to the network. In some cases.

For example, the resources of one computer may be shared by connecting a plurality of terminal devices to one computer, and the resources of each workstation may be shared among the workstations connected to the network. In some cases.

The resource management unit 10 is located between the resource 11 possessed by the system and the process 12 that wants to use it, and manages the resource 11 when using the resource 1. The exclusive control matrix It has an exclusive control unit 101 for determining exclusive control by referring to 100, and an in-use resource storage unit 102 for storing the resource 11 in use.

The resources 11 (X, Y, Z) are various according to the purpose of the processing system, such as a file in a computer operating system and a document in a document processing system represented by a word processor, for example. There is one.

The process 12 (A, B, C) is, for example, from the start to the end of an interactive processing program started by a person who uses the processing system, and, for example, automatically in the processing system without human intervention. It automatically starts and ends. An example of the former is the text editor process,
An example of the latter is the daemon process.

The exclusive control matrix 100 is shown in FIG.
It is configured as shown in.

That is, an exclusive use mode corresponding to the conventional exclusive mode, a reference-only mode corresponding to the conventional shared mode, and an update shared mode are newly provided as modes for solving the problems of the prior art. Of these, the preceding process should have the exclusive use mode and the update sharing mode, and the following process should have all three modes, and the combination of these modes should determine the prohibition of use during sharing. I have to. FIG. 2 shows a matrix of such exclusive control of 2 modes × 3 modes.

According to the exclusive control matrix 100 of FIG. 2, for example, when the process A first starts using the resource X in the exclusive use mode, the subsequent process B waits until the process A ends. Utilization of resource X is not permitted. If the process A starts using the resource X in the update sharing mode, the subsequent process B uses the resource X.
Is only available in read-only mode.

When the exclusive use mode is provided, for example, when it is clear in advance that the consistency of the resource cannot be maintained while the resource is being updated, the consistency is maintained by blocking the reference from another process. There is an advantage that it is possible to suppress the reference of resources that have not been made.

FIG. 3 shows this exclusive control matrix 100.
Is a flow chart showing the flow of processing for determining permission or prohibition of use of the resource 11 with reference to FIG. 4, and FIG. 4 is a flow chart showing the flow of processing when the preceding process finishes using the resource. It is a chart.

The process flow will be described below.

First, when the process A tries to use the resource X, the process A issues a request to the resource management section 10 to use it. The content of the request specifies the name of the resource and the mode to be used, that is, the exclusive use mode, the update sharing mode or the reference only mode.

Upon receiving this request (step 30), the resource management unit 10 refers to the resource-in-use storage unit 102 to check whether or not the corresponding resource is in use (step 31).

If it is not in use, it is checked whether the request mode is the reference-only mode, and if so, the request mode is changed to the update sharing mode and the use of the resource X is permitted (steps 36, 37, 35). ). At the same time, the resource name and the mode of use are stored in the in-use resource storage unit 102.

Since the reference-only mode is not recognized in the preceding process A, the steps 36 and 37 are executed.
Is required.

However, when the resource X is being used,
The exclusive control unit 101 refers to the exclusive control matrix 100 to check whether the combination of the mode in use and the requested mode is possible or not (steps 32 and 33). Here, if yes, the use of the requested resource X is permitted, and at the same time, the resource name and the mode of use are stored in the in-use resource storage unit 102 (step 35). However, if not possible, use of the requested resource X is prohibited (step 34).

If there are a plurality of cases in which one resource is being used, it is judged that there is a combination of all of the plural modes in use and the request mode, if any combination is not possible. .

However, in the case described below, even if the combination is permitted to be used, the resource 11 may be temporarily unreadable or writable after the start of use.

That is, while the resource 11 being used by a plurality of processes 12 is being read or written by an instruction from any one of the processes 12 being used, that process 12 (for example, process A) is being executed. ) Except the other processes 12 (for example, process B,
C) is not allowed to read or write at the same time. This temporary prohibition is realized by the resource management unit 10 temporarily and exclusively using the resource 11 therein. In this way, the reference to the resource 11 in the state where the consistency is not maintained because the writing is in progress is suppressed.

By the way, when the preceding process A finishes using the resource X, and the succeeding process B simultaneously refers to the resource X in the reference-only mode, this time, the process B is executed.
Will be the predecessor process, but since the predecessor process is not allowed to use the reference-only mode, it must be switched to the update sharing mode.

FIG. 4 shows a process for this.
When the preceding process A finishes using the resource X, it is first checked whether or not there is a succeeding process (step 40), and if it does not exist, the process is terminated without doing anything.
However, if it exists, the mode of the subsequent process is changed to the update sharing mode, and that effect is notified to the subsequent process (step 41).

As a result, the subsequent process, which has been in the reference-only mode until now, changes its position to the preceding process, and at the same time, switches to the update sharing mode.

In this case, since the updating authority is given to the process, it is necessary to surely inform the user of the process to that effect so that the resources are not updated by mistake.

FIG. 5 shows a second embodiment of the exclusive control matrix 100, in which both the preceding process and the subsequent process are provided with the exclusive use mode, the reference only mode, and the update sharing mode. is there.

According to the exclusive control matrix 100 of FIG. 5, for example, when the process A first starts using the resource X in the exclusive use mode, the subsequent process B keeps the resource X at the end until the process A ends. Is not allowed to use. Further, when the process A starts using the resource X in the reference-only mode, the subsequent process B can start using the resource X in the reference-only mode or the update sharing mode even if the process A does not finish the use. Furthermore, if process A starts using resource X in update sharing mode,
Subsequent process B can start using resource X only in reference-only mode.

FIG. 6 shows a flow of processing for determining permission / prohibition of use with reference to such an exclusive control matrix 100 of 3 modes × 3 modes.

First, when the process A tries to use the resource X, the process A issues a request to the resource management section 10 to use it. The contents of the request specify the name of the resource and the mode to be used, that is, the exclusive use mode, the update sharing mode, or the reference only mode.

Upon receiving the request, the resource management unit 10 refers to the resource-in-use storage unit 102 to check whether the corresponding resource is in use (steps 60, 61). If it is not in use, the requested use is permitted, and at the same time, the resource name and the mode of use are stored in the in-use resource storage unit 102 (step 65).

If it is in use, the exclusive control unit 101
Thus, referring to the exclusive control matrix 100 of FIG. 5, it is checked whether or not the combination of the mode in use and the requested mode is possible (steps 62 and 63). If yes, the requested use is permitted, and at the same time, the resource name and the use mode are stored in the currently used resource storage unit 102 (step 65).
If not, the requested use is prohibited (step 64).

If there are a plurality of cases in which one resource is being used, if there is a combination of all of the plurality of modes in use and the request mode, even if one combination is not possible, it is judged as not possible.

Examples of the processing system described above include, for example, the following.

In the operating system of a computer, if the present invention is applied to a file management unit that manages files that are its resources, an application program running on that operating system will notify the file management unit when using the file. It will specify the mode of use.

Further, in the case of a program running on an operating system to which the present invention is not applied, if the present invention is applied to a unique resource management unit that manages resources used by a group of application programs running under the program, The application program running on that program specifies the mode of use to its own resource management unit when using the resource.

A specific application example of the present invention will be described below.

FIG. 7 shows an example of editing and compiling a source program in parallel on a computer system to which the present invention is applied. In software development, there are many situations where it is desired to compile a source program while compiling it and check the source program being edited for errors.

The user A activates the text editor in the update sharing mode in order to edit the source program.
At this time, the editing process requests the use of the source program in the update sharing mode (step 70). Since it is the first usage process, usage is unconditionally permitted.

Then, the user A edits and stores the source program (step 71), and activates the compiler to compile the stored source program. Here, the compilation process requires the use of the source program in the reference-only mode (step 72). It is permitted because the resource being used in the update sharing mode is used in the reference only mode. After this, compile (step 7
3) After that, the compilation result is displayed and output (step 74).

Subsequently, another user B activates the text editor in the update sharing mode in order to edit the same source program. At this time, the editing process requests the use of the source program in the update sharing mode (step 75), but the resource already in use in the update sharing mode tries to use the resource again in the update sharing mode, and thus is prohibited. .

Then, the first user A finishes editing,
When the editing process is complete (steps 76, 7
7), the use of another user B is permitted (step 7)
8).

FIG. 8 shows an example of writing a document using a text editor on a computer system to which the present invention is applied.

Although the document is stored a number of times during the writing without terminating the text editor, there are many situations in which it is not desired for others to read the stored document during the writing.

User A activates the text editor in the exclusive use mode to edit the document. At this time, the editing process requests the use of the document in the exclusive use mode (step 80). Since it is the first usage process, usage is unconditionally permitted.

Subsequently, the other user B activates the text editor in the reference only mode in order to refer to the same document. At this time, the editing process requires the use of the document in the reference-only mode (step 82), but it is prohibited because the resource already used in the exclusive-use mode is repeatedly used in the reference-only mode.

Therefore, the user A is guaranteed to create the document being written so that it cannot be read by others.

[0069]

As described above, according to the present invention, when a resource whose content can be updated is shared, even if the preceding process is in use for the purpose of updating, Since the reference-only mode that permits the use for reference only is provided, both the preceding and succeeding processes can effectively use the shared resources to efficiently proceed the processing of each process.

Further, since the exclusive use mode is provided, it is possible to perform processing in a form in which other processes are completely excluded, and it becomes possible to perform resource sharing more flexibly than ever before.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a processing system to which the present invention is applied.

FIG. 2 is a diagram showing a first embodiment of an exclusive control matrix used in the present invention.

FIG. 3 is a flow chart showing a procedure for performing exclusive control using the exclusive control matrix of FIG.

FIG. 4 is a flowchart showing a process when a preceding process finishes using the exclusive control matrix shown in FIG.

FIG. 5 is a diagram showing a second embodiment of an exclusive control matrix used in the present invention.

FIG. 6 is a flowchart showing a procedure of performing exclusive control using the exclusive control matrix of FIG.

FIG. 7 is an explanatory diagram showing an example of a case where a source program is edited and compiled in parallel by using the present invention.

FIG. 8 is an explanatory diagram showing an example of writing a document using the present invention.

FIG. 9 is a configuration diagram of a conventional exclusive control matrix.

[Explanation of Codes] 1 ... Processing system, 10 ... Resource management unit, 11 ... Resource, 1
2 ... Process, 101 ... Exclusive control unit, 100 ... Exclusive control matrix, 102 ... In-use resource storage unit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hidetoshi Suemune 6-81, Onoe-cho, Naka-ku, Yokohama-shi, Kanagawa Hitachi Software Engineering Co., Ltd. In-house (72) Yoshio Inamasu, Onou-cho, Naka-ku, Yokohama-shi, Kanagawa 81-chome Hitachi Software Engineering Co., Ltd. in-house (72) Inventor Yutoku Tajima 6-81 Onoue-cho, Naka-ku, Yokohama-shi Kanagawa In-house (72) Hitachi Software Engineering Co., Ltd. Kunihiro Ikeda Onoe-cho, Naka-ku, Yokohama-shi, Kanagawa 6-81 Hitachi Software Engineering Co., Ltd. In-house (72) Inventor Yoshio Imamura Onoe-cho, Naka-ku, Yokohama-shi, Kanagawa 6-81 Hitachi Software Engineering Co., Ltd. In-house (72) Instructor, Takasu Onou-cho, Naka-ku, Yokohama-shi, Kanagawa 6-chome 81 Earth Hitachi Software Engineering shares meeting-house (72) inventor Tsuji NoboriShigerudai Yokohama-shi, Kanagawa, Naka-ku, Onoe-cho, address 6-chome 81 Hitachi Software Engineering shares meeting house

Claims (2)

[Claims] 1. As a mode that can be specified when starting to use a resource whose content can be updated by a plurality of processes, an exclusive use mode and an update sharing mode are used for the preceding process and an exclusive use mode is used for the subsequent process. , The update sharing mode, and the reference-only mode are provided. By combining these modes, the resource that is being used by the preceding process in the exclusive use mode is prohibited from being used by the subsequent process, and the preceding process is used by the update sharing mode. The internal resource is a shared resource exclusive control method that allows only subsequent processes to be used in the reference-only mode. 2. The exclusive use mode, the update sharing mode, and the reference only mode for each of the preceding process and the succeeding process as modes that can be specified when starting the use of resources whose contents can be updated by a plurality of processes. To have
Due to the combination of these modes, the resource used by the preceding process in the exclusive use mode is prohibited from being used by the following process, and the resource used by the preceding process in the update shared mode is in the reference-only mode for the following process. Exclusive control of shared resources, characterized in that only the use in the reference-only mode is allowed, and the resource being used in the reference-only mode by the preceding process is only allowed in the reference-only mode or the update sharing mode for the subsequent process. method.