JPH0573383A - File access system - Google Patents

Abstract

PURPOSE:To structure a file system in tree structure matching the purpose of use by each user and to easily access a target file. CONSTITUTION:In the file system wherein respective files on a storage device 11 are rearranged in tree structure, virtual file systems by users are assumed and a correspondence table 12 showing correspondence relation between the file system in the tree structure and the virtual file systems by the users is generated. When a file on a virtual file system is accessed, a real/virtual conversion mechanism 13 refers to the correspondence table and converts the position of the target file on the virtual file system into a position on the file system in the tree structure and a file access mechanism 14 is used to access the target file.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a file access method for accessing files on a tree-structured file system. In other words, there is a file at the end of each branch of the tree, and there is a file for managing the file at the end of the branch out of the section at the branch node. The present invention relates to a method of accessing a file on a file system.

[0002]

2. Description of the Related Art FIG. 3 is a diagram showing an example of a tree-structured file system. If the current position of user A is dir1 and the current position of user B is dir3, si1. A conventional file access method for accessing c will be described. User A is dir1 → usr →
/ → work → src → cmd → sr1. In the route of c, the user B has dir3 → usr → / → work → s
rc → cmd → sr1. It was accessed by going through the route c.

That is, in the conventional file access method of this type, a common section at the upper position of the user's current position and a branch of the target file is searched, and the user finds the target file after reaching that section. I went down to the knot and accessed it.

[0004]

In the above-mentioned conventional file access method, the common position above the current position of the user and the branch where the target file is located is searched for, and after the user reaches that node, the target is searched. Because it goes down to a certain section of the file, it is inconvenient and easy to make mistakes when specifying the position if the path is long.

In the above example, users A and sr1. The common clause with "c" is "/", and the user A uses sr1. c
You have to go through as many as five passages to access.

[0006]

The present invention provides a file access method for accessing a target file in an actual file system in which each file is organized in a tree structure,
Assuming a virtual file system for each user, create a correspondence table showing the correspondence relationship of the path of the real file system and the virtual file system, and obtain the absolute path name on the virtual file system of the target file, The absolute path name on the virtual file system of the target file is converted to an absolute path name on the real file system based on the correspondence table, and the absolute path name on the real file system obtained by the conversion is used. It is characterized in that the target file is accessed.

[0007]

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

First, the terms used in the description of the embodiment of the present invention will be explained using the tree-structured file system shown in FIG. In FIG. 3, / (route), usr, tm
p, work, dir1, dir2, dir3, dir
A file located at a node of a tree branch, such as 4, src, or head, is called a directory file (hereinafter, directory). The current working directory is called the current directory, and the first directory that can be located when using the system is called the home directory.

An expression representing the position of a file or directory in a tree-structured file system is called a path name,
A path expressed starting from the current directory is called a relative path name, and a path expressed starting from the highest level in the file system is called an absolute path name. For example, in FIG.
k ”as the current directory, sr1. c,
The relative path name of src / cmd / sr1. c, the absolute path name is / work / src / cmd / sr1. c.

An embodiment of the present invention will be described below. In the tree-structured file system (actual file system) shown in FIG. 3, the virtual file system shown in FIG. 4A is assumed for user A whose dir1 is a home directory. That is, file and file2 that can be directly accessed from dir1 on the real file system are selected. Furthermore, sr that cannot be directly accessed from dir1
c and head are selected. Then, cmd, which is directly accessible from src, and sr1. c and sr2. c is selected. In addition, the file h is a file managed by sys2 and the directory sys2 that can be directly accessed from the head.
d2. h is selected. As a result, a correspondence table (FIG. 4B) showing the correspondence relationship between the paths of the real file system and the virtual file system is created.

Similarly, the home directory is dir.
A virtual file system for user B (see FIG. 4).
Assuming (c)), a correspondence table (Fig. 4 (d)) with the actual file system is created.

FIG. 1 is a functional block diagram of this embodiment. In this embodiment, the real file system is stored in the real file system storage device 11. The correspondence table between the real file system and the virtual file system is stored in the correspondence table table 12. Real / virtual conversion mechanism 1
3 converts the position on the virtual file system into the position on the real file system. The file access mechanism 14 uses the converted position to access the target file on the real file system. FIG. 2 is a flow chart for explaining a file access procedure by the real / virtual conversion mechanism 13 and the file access mechanism 14.

Next, the user A whose current directory is cmd on the virtual file system shown in FIG.
1. When the user B is accessing sr3. This embodiment will be described by taking the case of accessing c as an example.

First, in the case of user A, step 2 in FIG.
1, the relative position on the virtual file system,
That is, the result "cmd / sr1.c" is obtained as the relative path name. In step 22, the path to the current position, that is, the absolute path name to the current directory, "#
/ Src / cmd "information, steps 21 and 2
From the result of step 2, in step 23, "# / src / cmd / sr1.c" is obtained as an absolute position to the target file on the virtual file system, that is, as an absolute path name.

Next, the correspondence table shown in FIG. 4B is searched,
Convert the longest path name among the paths shown on the virtual file system side of the correspondence table that corresponds to the absolute path name obtained in step 23 from the one on the virtual file system to the corresponding path name on the real file system. Yes (Step 2
4). In this case, "# / src" is "/ work / s"
Since it corresponds to "rc", if that part is replaced, the result "/work/src/cmd/sr1.c" is obtained. This final result is sr1. The absolute path name of the file sr1. c is accessed (step 25).

In the case of user B, in step 21 of FIG. 2, the relative path name "# / li" on the virtual file system is used.
b / sr3. c ”is obtained. In step 22, the absolute pathname of the current directory is obtained, but in this case "#"
Therefore, the result of step 23 is “# / lib / sr3.c” which is the same as that of step 21.

Next, using the correspondence table of FIG. 4D, this is converted into a path name on the real file system (step 2).
4). In this case, "# / lib" is "/ work / sr"
Since it corresponds to "c / lib", if that part is replaced, "/work/src/lib/sr3.c" sr3. Get the absolute pathname of c. File access is performed using this (step 25).

[0018]

As described above, according to the present invention, the virtual file system for each user is assumed from the real file system, and the file access is performed by using the correspondence table showing the correspondence relationship with the real file system. , You can build a tree-structured file system that suits your needs, and
The target file can be easily accessed.

[Brief description of drawings]

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

FIG. 2 is a flowchart illustrating a procedure when performing file access according to the embodiment shown in FIG.

FIG. 3 is a diagram showing an example of a tree-structured file system that is a target of the present invention.

4 (a) and (b) are diagrams of an example of a virtual file system in the embodiment shown in FIG. 1 and a correspondence table with the actual file system, and (c) and (d) of the virtual file system, respectively. It is a table of another example and its corresponding file system.

[Explanation of symbols]

 11 storage device 12 correspondence table 13 real / virtual conversion mechanism 14 file access mechanism

Claims (1)

[Claims] 1. In a file access method for accessing a target file in a real file system in which each file is arranged in a tree structure, a virtual file system is assumed for each user, and the real file system and the virtual file system are assumed. A correspondence table showing the correspondence relationship of the paths with and is obtained, the absolute path name of the target file on the virtual file system is obtained, and the absolute path name of the target file on the virtual file system is based on the correspondence table. Then, the file access method is characterized by converting to an absolute path name on the real file system and accessing the target file by the absolute path name on the real file system obtained by the conversion.