JPH0659953A - Method for controlling input/output of virtual file - Google Patents

Abstract

PURPOSE:To access plural divided real files by including a function for determining the access order of divided files to a virtual file name. CONSTITUTION:A virtual file corresponding to divided files 31 to 33 is defined as A, and at the time of allocating files, the upper limit of key values in each division is registered in a division key table 1, divided file names corresponding to the virtual file name are registered in a divided file allocating table 2 and the order of the divided file names is used as the order for sequential access. When the virtual file A is accessed by a value 'f', the divided file 32 based upon 'f<h' is selected by the table 1 and key specification access is applied to the file 32 by using the key value 'f'. When a user accesses next to a record with a key value 'c' in the file 31, the end of the file 31 is detected and input/ output control refers to the table 2 and accesses the file 32.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a virtual file input / output control method, and more particularly to a virtual file input / output control method for inputting / outputting data across a plurality of real files by designating one virtual file name. .

[0002]

2. Description of the Related Art A conventional virtual file input / output control method is
Input / output control of one file is performed for one file name.

[0003]

In the above-mentioned conventional virtual file input / output control method, it is possible to allocate one file over a plurality of media, but at this time, the user is aware of the media individually. Therefore, it is difficult to satisfy the user's demand for accessing this file as one large file or as a small file for each medium.

[0004]

A file input / output control method of the present invention has a division file allocation function for inputting / outputting a plurality of real files (divided files) for one virtual file name, and those functions. On the other hand, it is characterized by including a split key access function for performing key designation input / output and a split file sequential access function for determining the access order of split files with respect to a virtual file name.

[0005]

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

FIG. 1 shows allocation of divided files according to an embodiment of the present invention. The divided files 31, 32 and 33 are composed of records of the same format and are classified by the key part. Let A be a virtual file for these divided files.

At the time of file allocation, the upper limit of the key value for each division (more precisely, the leading key of the next division file) is registered in the division key table 1, and the division file allocation table 2 stores virtual files. What division file name corresponds to the name is registered. The order of the divided file names registered in the divided file allocation table 2 is the order of the sequential access.

When the virtual file A allocated in this way is accessed with the value of "f", the divided file 32 is selected with "f <h" by the divided key table 1, and the divided file 32 of "f" is selected. Key-specified access is performed by the key value. Further, when the user tries to access the virtual file A sequentially from the beginning to the end, when the user accesses the next of the record of the key value “c” of the divided file 31, the end of the divided file 31 is detected,
For input / output control, the divided file allocation table 2 is referred to access the divided file 32.

In this way, access is sequentially performed until the end. Of course, it is possible to alternately use the key-specified access and the sequential access. Further, since each divided file is assigned as one independent file, if the virtual file allocation table is separately defined as "B", each file can be used independently.

[0010]

As described above, according to the present invention, it is possible to generate a plurality of divided real files in the same way as when accessing a conventional file, by making the user aware of only one virtual file name. Can be accessed. further,
The divided real files can also be used individually, which has the effect of improving the efficiency in file input / output processing.

[Brief description of drawings]

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

[Explanation of symbols]

 1 split key table 2 split file allocation table 31-33 split file

Claims (1)

[Claims] 1. A virtual file input / output, comprising: means for allocating a real file for a specified virtual file name; and means for inputting / outputting a real file of input / output data required for the virtual file. Control method.