JPH05204725A - File managing device - Google Patents

Abstract

PURPOSE:To improve the efficiency of use by decreasing useless unused areas and to prevent the number of times for access to an external storage device from being increased by dividing a data storage area into plural clusters having various capacity, and constituting a file by combining the plural clusters having various capacity. CONSTITUTION:A ROM 12 to store fixed data such as a prescribed program and character font data, RAM 13 to temporarily store data used for arithmetic or an arithmetic result, and external storage control part 15 to control an external storage device 14 such as a floppy disk drive device or the like are respectively connected to a CPU 11. A file managing device 10 divides the data storage area of the external storage device 14 into the plural clusters having various capacity (4Kbyte and 1Kbyte) and manages the clusters by managing the connection information of the plural clusters having various capacity stored in a managing area, and the file is constituted by combining the plural clusters having various capacity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a file management device, and more particularly to a file management device with improved efficiency of use of an external storage device.

[0002]

2. Description of the Related Art A file device is essential as a device for storing, storing, and retrieving information in an information processing system. Even in office automation systems, programs, numerical data, character data,
A file device is required to record image data and the like. There are various types of file devices regarding whether a storage medium can be exchanged, whether data can be additionally recorded or erased, a storage capacity, and an access time. For example, a hard disk device (HDD) uses a base material mainly made of an aluminum alloy material as a storage medium, and a floppy disk device (FDD) is a recording medium in which magnetic recording is performed on a disk-shaped plastic film. Is a device that uses. In general, the FDD data recording format is a sector format in which a fixed length such as 512 bytes is one block, and data reading and writing is performed in sector units. Therefore, prior to writing data, the system initializes (also called formatting). In the file management method of the file device, the data area is divided into units called clusters (one track is sometimes called a cluster), and the clusters are used as units.
Data is being read / written. Also, FAT
A table called a (management area table) manages in what order these clusters are connected to form one file. Generally, the cluster is divided in units of 1 Kbyte, 4 Kbyte, and the like. For example, an example in which the data area of the external storage device is divided into clusters of 4 Kbyte units is shown in FIG. 4, and a predetermined file is formed in the external storage device having the divided clusters. The management area in FIG. 4 is an area for storing data for managing file name / cluster chain information.

[0003]

However, in such a conventional file management device, the data area has a cluster of the same capacity (for example, 1 Kbyte or 4 Kbyt).
e) Divide and read data in cluster units
Since writing was performed, for example, as shown in FIG.
When creating a 5 Kbyte file in an external storage device that has clusters divided in units of 4 Kbytes, 2 clusters are used as shown in the hatching part in the figure, which means that an area of 8 Kbytes will be taken and (8-5 = 3 Kb
yte) has a problem that it becomes an unused area and the use efficiency deteriorates. Further, if the cluster size is reduced to increase the usage efficiency, not only the FAT area for managing the cluster becomes large, but the effective data area for reading / writing data is decreased, and the external storage device is accessed. There was a problem that the speed decreased because the number of times increased. If you try to use multiple types of clusters with different capacities according to the situation, you can reduce the unused area as much as possible and improve the usage efficiency.
It is obvious that the number of accesses to the external storage device will not increase. An object of the present invention is to improve the efficiency of use of the external storage by making it possible to properly use a plurality of types of clusters having different capacities.

[0004]

The means of the present invention are as follows. (1) Dividing the data storage area of the external storage device into clusters of a plurality of types of capacities. For example, a data area of an external storage device such as a floppy disk drive device is divided into a cluster having a predetermined capacity and a cluster having a capacity smaller than the cluster of that capacity. In this case, the size / type of the cluster is set to be the most suitable for the system in accordance with the capacity / purpose of use of the external storage. (2) A means for managing the cluster by managing connection information of the clusters of the plurality of types of capacities. For example, management is performed using a management area that stores connection information including free information of clusters having a plurality of types of capacities. (3) A file is constructed by combining clusters of the plurality of types of capacities. For example, when writing data to an external storage device, control is performed so as to configure a file by combining clusters of multiple types of capacities so that the unused area of the data storage area is reduced as much as possible and the number of accesses is not increased. It is executed by the CPU or the like.

[0005]

The operation of the means of the present invention is as follows. First,
The data storage area of the external storage device is divided into a plurality of types of capacities by clusters, and the connection information of the divided clusters of a plurality of types of capacities is managed by the management means. And
Data reading / writing is performed on a file by combining the clusters of the plurality of types of capacities. Therefore,
It is possible to reduce useless unused areas as much as possible and improve usage efficiency.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment will be described below with reference to FIGS. 1 to 3 are diagrams showing an embodiment of a file management device. First, the configuration will be described. FIG. 1 is a block diagram of the file management device 10. In this figure, reference numeral 11 denotes a CPU that controls the entire apparatus and performs various data processing including data writing processing described later, and the CPU 11 performs various operations of the data processing apparatus according to a micro program stored in a ROM 12 described later. Control. C
The PU 11 includes a ROM 12 that stores fixed data such as a predetermined program and character font data, and a RAM 1 that temporarily stores data used for calculation and calculation results.
3. An external storage controller 15 for controlling an external storage device 14 such as a floppy disk drive device (FDD) is connected to each.

The storage area of the ROM 13 is divided and used for each predetermined application (for example, a work area, a table area, and an area for reading / writing data from an external storage). The external storage control unit 15 also controls reading / writing of data from the external storage device 14 and reading of status under the control of the CPU 11.

FIG. 2 is a diagram showing a file structure in which the data area of the external storage device 14 is divided into clusters of a plurality of capacities. In this embodiment, the data area is divided into 4 Kbyte / 1 Kbyte clusters. As shown in FIG. 3, the data area of track numbers 0 to 2 is a management area (8 Kbytes).
And a data area of track number 3 is divided into clusters 1 to 12 of 1 Kbyte.

Next, the operation of this embodiment will be described. FIG. 3 shows an external storage device 1 having the above-mentioned clusters of plural kinds of capacities.
4 is a flow chart showing a data writing process when writing data in No. 4, in which reference numeral Cn (n = 1, 2, ...) Indicates each step of the flow. Here, the external storage device 1
4 has 10 clusters of 4Kbyte data area, 1K
Format with 12 byte clusters 4 /
Let 1r / sr be the number of vacant clusters of 1 Kbyte. The data to be written is wd bytes from the address adr.

When the program starts, first, at step C1, the free capacity of the external storage data is equal to or larger than the number of bytes of write data wd ((4 × lr + 1 × Sr) Kbyte ≧ w
d)), and if the free space of the external storage is insufficient, it means that the data cannot be written to the external storage device 14, so the processing of this flow is ended. When the free space of the external storage data is wd or more, step C2
The number of bytes of data to be written in (write byte) wd is 4 Kb
It is judged whether it is yte or more (wd ≧ 4Kbyte), and when the number of bytes wd of the data to be written is smaller than 4Kbyte, writing this data into a data area divided by a 4Kbyte cluster causes an unused area. Then, it is determined that the usage efficiency is reduced, and the process proceeds to step C3. At step C3, is the total capacity (1 × Sr) Kbyte of a 1 Kbyte cluster smaller than the number of bytes wd of the data to be written ((1 ×
Sr) Kbyte <wd) is determined, and (1 x Sr) Kby
When te <wd or in step C2 above wd ≧ 4 Kb
If yte, it is determined in step C4 whether or not there is a space in the 4 Kbyte cluster.

When there is a space in the 4 Kbyte cluster, the data is written in the 4 Kbyte free cluster from the address adr to the 4 Kbyte free cluster-1 (lr =
lr-1), the write address is updated in step C6 (adr ← adr + 4Kbyte), and the write byte is updated (wd ← wd-4Kbyte) in step C2.
Return to. The update of the write address and the update of the write byte are performed on the data in the management area shown in FIG. Step C
When the writing of all data is completed in 6, the processing of this flow is completed.

When the total capacity of the 1 Kbyte cluster is equal to or larger than the write byte wd in the step C3, it is judged that the data area of the 1 Kbyte cluster can be written, and the step C
If there is no free space in the 4 Kbyte cluster in step C4, the process goes to step C7 to write in the data area of the free 1 Kbyte cluster.
At Step C7, 1 Kbyte of data is written in the free area of the 1 Kbyte cluster from the address adr to make the free cluster-1 (Sr = Sr-1), and the write byte is updated (wd ← wd-1 Kbyte) at Step C8 and then the step C
Returning to 7, all the data is written in the cluster of 1 Kbyte, and the processing of this flow ends.

As described above, the file management apparatus 10 divides the data storage area of the external storage device 14 into a plurality of capacities (4 Kbyte clusters and 1 Kbyte clusters) and stores a plurality of capacities stored in the management area. The cluster connection information is managed to manage the clusters, and the clusters of multiple capacities are combined to form a file. Therefore, when 5 Kbytes of data is written by the data writing process of FIG. When the area is divided into 4 Kbyte clusters, 8 Kbytes are required as shown in the hatched portion in FIG. 4, but in this embodiment, as shown in the hatched portion in FIG. 2, 5 Kbytes are obtained by combining 4 Kbyte clusters and 1 Kbyte clusters. Data can be written, and the usage efficiency of the external storage can be significantly improved.
In this case, in the conventional one in which the cluster size is simply reduced to improve the usage efficiency, the FAT area becomes large, and the number of accesses to the external storage increases, which slows down the speed. In the embodiment, since the file is composed of a combination of clusters having a plurality of capacities, the above problems can be avoided as much as possible. As a result, it is possible to efficiently save the data in the external storage without using a useless area.

In the present embodiment, the clusters of a plurality of types of capacities are 4 Kbytes and 1 Kbytes, but of course, the present invention is not limited to this, and the size / type of clusters may be set in accordance with the capacity of the external storage / purpose of use. It can be configured to be the most suitable for the system.

Further, in the present embodiment, an example in which the processing result of the data writing processing is stored in the management area of the data storage area is shown. However, the management area is of any form as long as it manages the file name / cluster. It may be something like this.

Further, in the present embodiment, an example of performing the data writing process is shown as an example of the data processing, but the present invention is not limited to this, and any process may be performed as long as the data processing is performed.

[0017]

According to the present invention, since the data storage area of the external storage device is divided into a plurality of types of capacities by clusters, useless unused areas can be reduced as much as possible to improve the usage efficiency. It is possible to prevent the number of accesses to the external storage device from increasing.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a file structure in which a data area of an external storage device is divided into clusters of a plurality of capacities.

FIG. 3 is a flowchart showing a data writing process of the file management device.

FIG. 4 is a diagram showing a file structure in which a data area of a conventional external storage device is divided into clusters having a plurality of capacities.

[Explanation of symbols]

 10 File Management Device 11 CPU 12 RAM 13 ROM 14 External Storage Device 15 External Storage Control Unit

Claims (1)

[Claims] 1. A file management device that divides a data storage area of an external storage device in units of clusters and manages connection information of the divided clusters to form a file, wherein a plurality of data storage areas of the external storage device are provided. It is divided into clusters of different capacities, the connection information of the clusters of plural capacities is managed to manage the clusters, and the clusters of plural capacities are combined to form a file. File management device.