JPH05342070A - File information managing method - Google Patents

Abstract

PURPOSE:To efficiently manage file information by shortening an access time required for opening the same file by plural processes. CONSTITUTION:When a master file 10 opens a file 16, a file information table 18b is prepared in an extention system area 18a possessed by a file information managing part 18. When a slave process 12 issues an open instruction to the same file 16, the file information table 18b is copied in a memory 12a for slave process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of managing file information when a process opens a file.

[0002]

2. Description of the Related Art FIG. 3 schematically shows the concept of a conventional file information management method. In the figure, both the parent process 10 and the child process 12 are configured by software (for example, application program). The child process 12 is generated when, for example, a fork instruction is executed in the parent process 10, and corresponds to a copy of the parent process 10 itself.

Here, each of the processes 10 and 12 has its own dedicated storage areas (memory) 10a and 12a on the main memory.
File information tables 10b and 12b are stored in 0a and 12a as described later.

These processes 10 and 12 are executed on a so-called operating system (OS). The OS includes a data management module 14 in this conventional example, and data about files 16 and the like. It manages I / O.

Here, the file 16 corresponds to a database on a storage device, a kanji dictionary, or the like. The file information described above is data representing the length and number of records in the file 16, attributes, dates, and the like.

Next, a conventional method of creating a file information table will be described.

First, the file 16 is opened during execution of the parent process 10, and then the parent process 10 creates a child process 12. When the file 16 is opened, the data management module 14 creates a file information table for the parent process 10 and sends the file information table 10b to the parent process memory 10a.

On the other hand, when the child process 12 opens the same file 16, the same process as above is executed. That is, the file 16 is opened via the data management module 14, and the file 1
A file information table for 6 is created and written in the child process memory 12a as a table 12b.

[0009]

As described above, in the conventional method, each time a parent process and a child process issue a file open command, file information is obtained from the file and the file information is obtained by each process. It was stored in the memory it manages.

Therefore, when the number of opened files increases, the number of times of accessing the files also increases, which causes a problem that the time performance of the information processing apparatus (computer) is deteriorated. Therefore, it has been desired to omit duplicate access.

The present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to shorten the access time required for a plurality of processes to open a file and perform efficient management of file information. It is to provide a method of managing file information that can be done.

[0012]

In order to achieve the above object, the present invention is a file information management method for managing file information of files opened by a parent process and a child process as a table in association with each process. hand,
The file information of the file opened by the parent process is stored as a table on a predetermined shared memory, and when the child process issues an open command to the same file, the file information table on the shared memory is stored. It is characterized by copying on the memory managed by the child process.

[0013]

According to the above structure, when the parent process opens a file, a file information table of the file is created on a predetermined shared memory. When the child process issues an open command to open the same file, the file information table on the shared memory is directly copied to the child process memory without accessing the file.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 conceptually shows the configuration of the information processing apparatus of this embodiment, and the file information management method according to the present invention is applied to this information processing apparatus.
It should be noted that the same components as those of the conventional configuration shown in FIG. 3 are designated by the same reference numerals and the description thereof will be omitted.

In FIG. 1, in this embodiment, a "file information management unit 18" is provided between the parent process 10 and the child process 12 and the data management module 14. The file information management unit 18 exists as a part of the OS together with the data management module 14.

The file information management unit 18 is a part of a system area managed by the OS (for example, an OS management area on the main memory) and is an extended system area 18 directly managed by itself.
owns a. This extended system area 18a is O
Since S manages, parent process 10 and child process 12
Function as a shared memory of.

In this embodiment, when the parent process 10 opens the file 16, the extended system area 18a stores the file information output by the data management module 14 as a table 18b. However, as will be described later, this measure can be selected, and depending on the case, the file information table 10b is stored in the parent process memory 10a.
(The content is the same as 18b) can also be created.

In this way, the parent process 10 has the file 1
When No. 6 is opened, the file information table is created in the extended system area 18a as the shared memory.
Then, as will be described later, the file information table 18a is copied to the memory 12b for the child process 12 at the same time when the file open command of the child process 12 is issued. That is, in this embodiment, when the file is opened by the child process, the file information is read again from the file 16 and the duplication of creating the file information table in the memory 12a of the child process 12 is avoided. The information table is immediately copied to shorten the access time.

In this embodiment, for ease of explanation,
Although the data management module 14 and the file information management unit 18 are provided separately, the data management module 14 may of course include the file information management unit 18 and fulfill its function.

Next, the specific operation of the file information section 18 of this embodiment will be described with reference to FIG. 1 and FIG. In the following description, a case will be described in which a parent process, a child process, and a grandchild process (processes that are children of the child process) exist. However, the present embodiment can be applied even if the layers are further hierarchized.

When any of the processes issues a command to open the file 16, in S101, there is a parent process immediately above the process, and the parent process already specifies "use shared memory". To determine if the file is open. For example,
If the process in which this routine is started is the parent process, the result is "No", and the process proceeds to S102. If it is a child process, the process proceeds to S102 or S105 depending on the result of the condition determination in S101. The same applies to the grandchild process, but here, the process that is a parent from the viewpoint of the grandchild process is the child process. That is, at any stage of the hierarchy, this routine is executed while judging the relationship between the "parent" and the "child".

In step S102, it is determined whether "use of shared memory" has been designated for the process that has entered this routine. Here, "use of shared memory" can be specified by the user in each process.

If "Yes" in S102, S10
At 3, the file information table 18b is created in the extended system area 18a for the process corresponding to its own child. On the other hand, if “No” in S102, S104
Then, as in the conventional case, the file information table 10b is created in the memory 10a for the parent process 10.

Now, in the case of "Yes" in S101,
In step S105, as in step S102, it is determined whether "use shared memory" has been designated for the process that has entered this routine.

If "No" in S105, S106
In, the extended system area 18 created in S103
The file information table 18b on a is copied to the memory 12a of the child process.

If "Yes" in S105, S10
At 7, the file information tables for parent and child processes stored in the extended system area 18a are copied to the extended system area 18a itself for child and grandchild processes.
Note that this copying is not always necessary, and the same file information table may be shared by the parent, child, and grandchild.

In the above embodiment, all of the file information about the file 16 is stored as a table in the extended system area 18a, but some of the shared file information is used as a file information table. It may be created on the area 18a. This makes it possible to effectively use the extended system area and prevent adverse effects on process execution even when the number of open files increases.

[0029]

As described above, according to the present invention,
A file information table is created on a predetermined shared memory, and the file information table is copied to the child process memory in response to the open instruction of the child process. It is possible to manage the file information as a whole.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a configuration of an information processing apparatus to which a file information management method according to the present invention is applied.

FIG. 2 is a flowchart showing an operation of a file information management section 18 shown in FIG.

FIG. 3 is a conceptual diagram showing the concept of a conventional file information management method.

[Explanation of Codes] 10 Parent Process 12 Child Process 14 Data Management Module 16 File 18 File Information Management Unit 18a Extended System Area

Claims (1)

[Claims] 1. A file information management method for managing file information of files opened by a parent process and a child process as a table in association with each process, wherein file information of files opened by the parent process is shared in a predetermined manner. A file is stored in a memory as a table, and when the child process issues an open command to the same file, the file information table in the shared memory is copied to a memory managed by the child process. How to manage file information.