JP2000089983A - Data storage device and method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To retain data properly corresponding to the state of existent data by compressing new data which are already stored in a data storage means according to the past update history made to correspond thereto and increasing the storable capacity when the new data are retained. SOLUTION: A check is made to judge that the rest capacity of the free area of a storage device 13 is less than the capacity of object document data to be saved and a storable free area is not secured in the storage device 13. In this case, it is judged whether or not there is uncompressed data files of a file management area read out of the storage device 13 to a work memory 14. When so, the file having the minimum past access frequency and the oldest final access date is searched from among them and the corresponding data are extracted from the actual data area of the storage device 13. The data are compressed by a compressing and uncompressing circuit 15 and stored and saved in the actual data area in the storage device 13 and file management data are updated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data storage device for storing and managing data such as images and documents to be processed in an electronic device having a data storage function such as a personal computer, an electronic organizer and a word processor. Data storage method.

[0002]

2. Description of the Related Art For example, data such as images and documents that are browsed, created, and edited by a personal computer are stored and stored in a storage medium such as a floppy disk or a hard disk.

Generally, data is stored by adding new data one after another to a storage medium having a limited storage capacity. In the storage function of various data, in order to use the storage capacity of the storage medium as effectively as possible,
Data that has not been accessed for a long time is determined to be unnecessary data at regular intervals and is automatically deleted, or data is automatically compressed and saved, so that the total amount of data to be saved Has been conventionally performed.

[0004]

However, in the conventional data storage function, when data that has not been accessed for a long time is simply automatically deleted at regular intervals,
If necessary data may be lost, and if the data is automatically compressed and stored, the necessary data will not be lost, but the compression processing and reading that accompany the data storage will not be necessary. There is a problem that each of the decompression processes requires a long time, and it is not possible to perform a storage process appropriately corresponding to the situation of already stored data.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and provides a data storage device and a data storage method capable of appropriately storing data in the state of already stored data. The purpose is to provide.

[0006]

That is, in the data storage device according to the first aspect of the present invention, new data is stored in the data storage means for storing data in association with the past update history of the data. In doing so, the data already stored in the data storage means is compressed according to the past update history associated with it and the storable capacity is increased. Low data is compressed to secure a storable area, and new data is stored.

In the data storage device according to a second aspect of the present invention, in the data storage device according to the first aspect, the past update history is used as the frequency of use. For example, infrequently used data is compressed to secure a storable area, and new data is stored.

In the data storage device according to a third aspect of the present invention, in the data storage device according to the first aspect, the past update history is used frequency and storage date and time data. In accordance with the frequency and the storage date and time, for example, data having a low usage frequency and an old storage date and time is compressed to secure a storable area, and new data is stored.

Further, in the data storage device according to a fourth aspect of the present invention, in the data storage device according to the second or third aspect, the data compression ratio of the data to be compressed by the data compression means is reduced. Since the frequency of use is changed in accordance with the frequency of use in the past, for example, as the frequency of use is lower and the necessity is lower, the compression rate is reduced by a higher compression ratio to secure a large storable area, and new data is stored. .

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of a personal computer having a data storage device according to an embodiment of the present invention.

This personal computer has a control unit 11 composed of a CPU.

The control unit (CPU) 11 includes a key input unit 12
In response to a key input signal from the control unit 11, a system program or various application programs stored in advance in the control unit 11 or an application program stored in the storage device 13 are started, and according to the started program, The work memory 14 is accessed to control the operation of each part of the circuit.

The control unit (CPU) 11 is connected to a compression / decompression circuit 15 and a display unit 16 in addition to the key input unit 12, the storage device 13, and the work memory 14.

The key input unit 12 includes various character and symbol input keys, numeric keys, function keys, execution keys,
A cursor key and the like are provided.

The storage device 13 is, for example, a hard disk device. The header of the hard disk is provided with a file management area 13a (see FIG. 2). Real data area 1 where each data file is stored
3b (see FIG. 3) and the like.

The work memory 14 is, for example, a RAM composed of a semiconductor memory. The RAM is input to and output from each circuit unit in accordance with instructions from the control unit 11 accompanying execution of various application programs. Various data is temporarily stored as needed.

The compression / decompression circuit 15 performs a compression process associated with the storage of the image data, audio data, document data, and the like processed by the personal computer in the storage device 13 and a reading process from the storage device 13. As the compression algorithm used in the compression / decompression circuit 15, for example, JPEG is used for image data, and LHA is used for document data. A bit conversion algorithm is used.

The display section 16 uses a liquid crystal display panel such as a TFT, and displays various data processed by the personal computer.

FIG. 2 is a diagram showing a configuration of a file management area 13a provided as a header of the storage device 13 in the personal computer.

FIG. 3 is a diagram showing the configuration of the actual data area 13b provided in the storage device 13 of the personal computer.

The file management area 13a includes a data number as a serial number, a file name as a title, a frequency data as an access frequency, and a latest access time for each data file stored and saved in the actual data area 13b. , A compression flag indicating whether or not the data is compressed and stored (compression “1”, non-compression “0”), and a data pointer indicating the head storage address in the real data area 13b. Stored and managed.

In the real data area 13b, real data of each data file managed in the file management area 13a is stored with its respective data pointer as a head storage address.

Next, the data storage function of the personal computer having the above configuration will be described.

FIG. 4 is a flowchart showing a data storage process by the personal computer.

For example, arbitrary document data is created on the work memory 14 in accordance with a document creation program stored in advance in the control unit 11 and displayed on the display unit 16. When data storage is instructed, the data storage processing in FIG. 4 is started.

When the data saving process is started, first, the remaining amount of the free area in which no data is stored in the storage device 13 is checked (step S1).

Whether or not the remaining amount of the free area in the storage device 13 is less than the data capacity of the document data to be stored this time, that is, the current storage state of the storage device 13 as it is It is determined whether an empty area larger than the capacity of the document data to be secured cannot be secured (step S2).

Here, it is determined that the remaining amount of the free area in the storage device 13 is not less than the data capacity of the document data to be stored, and it is confirmed that a sufficient free area is secured in the storage device 13. Then, data is stored and saved in the free area of the real data area 13b in the storage device 13, and the work memory 14 includes data No., file name, frequency data, time stamp, compression flag, and data pointer. File management data is input and generated, and the storage device 13
Is transferred and stored in the file management area 13a and updated (steps S2 → S3).

On the other hand, it is determined that the remaining amount of the free area in the storage device 13 is smaller than the data capacity of the document data to be stored, and no free area capable of storing the document data is secured in the storage device 13. In this case, the compression flag “0” for each data file in the file management area 13 a read from the storage device 13 to the work memory 14 is searched, and the uncompressed data file stored without being compressed is searched. It is determined whether or not it exists (step S2 → S4).

If it is determined that there is a data file that is uncompressed data whose compression flag is set to "0" in the file management area 13a, the frequency of the uncompressed data file is determined. A data file in which the number of past accesses indicated by the data is the least and the date of last access indicated by the time stamp is the oldest is searched, and the storage device 13 according to the head storage address indicated by the data pointer is searched. The corresponding data is extracted from the actual data area 13b (step S4 → S5).

Then, data extracted from the actual data area 13b in the storage device 13 and having the least access frequency and the oldest last access date are stored in the compression / decompression circuit 1
5 and subjected to data compression processing, the data is overwritten again from the position of the same head storage address in the actual data area 13b in the storage device 13 and stored. Then, the compression flag in the file management area 13a associated with this data file is set to "1", and the file management data is updated (step S).
6).

In this case, in the real data area 13b of the storage device 13, a new free area is reserved for the compression processing of the uncompressed data.

After a new free area is secured by compressing and saving the least frequently accessed / oldest data among the uncompressed data in the storage device 13,
When it is determined that the remaining amount of the free area in the storage device 13 is not less than the data capacity of the document data to be stored, and it is confirmed that a sufficient free area is secured in the storage device 13, The data storage processing is performed on the empty area of the actual data area 13b, and the data No., file name, frequency data, time stamp,
File management data including a compression flag and a data pointer is input and generated, transferred to and stored in the file management area 13a of the storage device 13 and updated (steps S6 → S).
2 → S3).

On the other hand, even after a new free area is secured by compressing and saving the least frequently accessed / oldest data among the uncompressed data in the storage device 13, the storage device The remaining free space is
If it is still determined that the data capacity of the document data to be stored is less than the data capacity of the document data to be stored, and if a free area capable of storing the document data is not secured in the storage device 13, the compression flag for each data file in the file management area 13a is set. "0" is searched again, and it is determined whether or not there is another uncompressed data file stored without being compressed (steps S6 → S2 → S4).

If it is determined that there is a data file which is uncompressed data whose compression flag in the file management area 13a is set to "0", the data file is further processed as described above. A new free area is secured by compressing and saving the least frequently accessed / oldest data, and a comparison is made with the data capacity to be saved (steps S4 to S6 → S2).

Thereafter, the compression flag for each data file in the file management area 13a is left as it is determined that the remaining amount of the free area in the storage device 13 is still less than the data capacity of the document data to be stored. Are set to "1" indicating that all the files have been compressed, and if it is determined that there is no uncompressed data file, the frequency data for each data file and the time stamp in the file management area 13a are used. Is searched for, and the data file whose last access date and time indicated by the time stamp is the oldest is searched, and the file name is displayed on the display unit 16 together with a message indicating whether or not the data can be deleted. It is displayed (step S2 → S4 → S7).

Then, in accordance with the message indicating whether or not deletion is possible, displayed on the display unit 16, the user is instructed to delete the data file with the least number of accesses and the oldest date of the last access, and is acknowledged by the user. Then, the data file is deleted from the actual data area 13b of the storage device 13, and the management data of the data file in the file management area 13a is also deleted (step S8 → S
9).

In this case, in the real data area 13b of the storage device 13, a new free area is secured by the amount of the deletion processing of the data file with the least number of accesses and the oldest date of the last access. State.

After a new free area is secured by deleting the least frequent / oldest data in the storage device 13, the remaining free space in the storage device 13 is less than the data capacity of the document data to be stored. When it is determined that a sufficient free area has been secured in the storage device 13, data storage processing is performed on the free area of the actual data area 13b in the storage device 13 and the work is performed. Memory 14
, File management data including a data No., a file name, frequency data, a time stamp, a compression flag, and a data pointer are input and generated, transferred to and stored in the file management area 13a of the storage device 13 and updated (steps S9 → S2 →). S3).

On the other hand, in the step S7, a message is displayed on the display section 16 for prompting whether or not the data file in the real data area 13b having the least number of accesses and the last access date is the oldest can be deleted. If the operation of acknowledging the deletion of the data file is not performed in a state where the data file is to be stored, it is determined that it is impossible to secure an empty area larger than the data capacity of the data file to be stored in the storage device 13, and the “save impossible” Is displayed on the display unit 16 (step S8 → S10).

As described above, when data is stored,
If no free area larger than the data capacity of the data file to be saved is found in the storage device 13, first,
It is determined whether the least frequently accessed and oldest data of the uncompressed data file is compressed and stored again, a new free area is secured, and a free area larger than the data capacity to be stored is obtained. If the uncompressed data is compressed from the least-accessed / least-accessed data and the free area is not obtained by securing the free area, the storage device 13 is further added. It is required to delete the oldest data with the least frequency of access, and only when this data deletion is acknowledged, the data is deleted and a new free area is secured, and the free space equal to or larger than the data capacity to be stored is obtained. It is determined whether or not an area has been obtained, and the compressed data of the uncompressed data or the least-accessed / least-old data is deleted to thereby exceed the data capacity to be stored. When the free area is obtained, since the storage to the storage device 13 of the data is made, again to save over compressed from a less needed frequency data, also,
Unnecessary old data can be deleted and new data can be stored, and data can be stored in the storage device 13 most efficiently.

FIG. 5 is a flowchart showing a data reading process by the personal computer.

When reading data files stored in the storage device 13 and instructing to read data, the data reading process in FIG. 5 is started and stored in the file management area 13a of the storage device 13. The file name of each data file that is
6 is displayed in a list.

When an arbitrary file name is selected and specified while the list of file names is displayed on the display unit 16, the file management data corresponding to the specified file name is stored in the file management area 13a. And is transferred to and stored in the work memory 14 (step A1).

Based on the compression flag "1" or "0" in the file management data of the data file designated to be read and transferred to the work memory 14, it is determined whether the data file is compressed data. (Step A2).

Here, if the compression flag in the file management data of the data file to be read is set to "1" and it is determined that the data file is stored as compressed data, Based on the head storage address of the storage device 13 indicated by the data pointer, the real data area 1 of the storage device 13
3b, the compressed and stored data file is read and transferred to the work memory 14, and the data file, which is the compressed data stored in the work memory 14, is decompressed by the decompression circuit 15 into non-compressed data. You. Then, the number of accesses indicated by the frequency data in the file management data is updated by adding +1 (step A2 → A3).

On the other hand, the compression flag in the file management data of the data file to be read transferred to the work memory 14 is set to "0", and it is determined that the data file is stored as uncompressed data. And the head storage address of the storage device 13 indicated by the data pointer in the file management data,
The data file stored in the actual data area 13b of the storage device 13 is read, transferred to the work memory 14, and stored as it is. Then, the number of accesses indicated by the frequency data in the file management data is +
It is updated by 1 (step A2 → A4).

As described above, when the data file to be read is stored as compressed data, the data file is read to the work memory 14, decompressed and stored (step A).
2 → A3) If the data file to be read is stored as uncompressed data, the data file is read to the work memory 14 and stored as it is (step A2 →
A4) When the data file read to the work memory 14 is displayed on the display unit 16, the read data file is stored in the real data area 1 of the storage device 13.
3b is temporarily deleted (step A5).

That is, the read data file is
The contents and length of the data change due to subsequent operations such as correction and editing, and the latest edited data must be saved as uncompressed data even if the data has been compressed and stored. The data file is deleted once, and then newly stored and saved.

When an arbitrary operation such as correction and editing of the data file read and displayed from the storage device 13 is completed, and a termination operation is instructed in the key input section 12, the work memory 14 is displayed. Is updated to +1 for the frequency data of the file management data corresponding to the data file, the time stamp is updated to the current date, and the compression flag is updated to "0" (step A6).
→ A7).

Then, the process shifts to the data saving process in FIG. 4, and the data file after the correction, editing, etc. is processed according to the same saving process (steps S1 to S10) as the actual data area 13b in the storage device 13. (Step AS).

Therefore, according to the data storage function of the personal computer having the above-described configuration, when data is stored, if no free area larger than the data capacity of the data file to be stored is found in the storage device 13, First, of the uncompressed data files, the least frequently accessed data and the oldest data are compressed and stored again, and a new free area is secured to obtain a free area larger than the data capacity to be stored. If the uncompressed data is compressed from the least-accessed / least-accessed data and the free area is not secured, the free space exceeding the data capacity to be saved cannot be obtained. It is required to delete the least frequently accessed data in the device 13 and the oldest data is deleted. It is determined whether a new free area is secured and a free area larger than the data capacity to be stored is obtained, and the storage is performed by compressing and storing the non-compressed data or deleting the least frequently accessed / oldest data. When an empty area larger than the data capacity to be obtained is obtained, the data is stored in the storage device 13, so that the data which is infrequently necessary is compressed and stored again, and unnecessary old data is deleted. Thus, new data can be stored, and data can be stored in the storage device 13 most efficiently.

In the compression / decompression circuit 15 of the personal computer in the above embodiment, the compression algorithm used is, for example, JPE for image data.
G, LHA etc. for document data, and a sampling period and sampling bit conversion algorithm for audio data. The compression / decompression circuit 15 compresses and stores uncompressed data in the data storage process. Although it has been described that the data is compressed and overwritten and stored, as the compression algorithm in the compression / decompression circuit 15, for example, for image data, BMP (bitmap) and JP with different compression methods (compression rates) are used.
Each of the compression algorithms of EG highest image quality, JPEG high image quality, and JPEG medium image quality is prepared. It is also possible to adopt a configuration in which a data compression process is performed by selecting a compression algorithm whose ratio has been changed from low to high.

FIGS. 6A and 6B are diagrams showing the types of data compression for image data and audio data. FIG. 6A shows the type of compression for image data, and FIG. 6B shows the type of compression for audio data. FIG.

That is, as shown in FIG. 6 (A), as the type of data compression for image data, the number of expression bits per pixel is as small as “24 bit color” → “16 bit color” → “8 bit color”. To change the number of dots in one screen data from "640x480dot" to "320x240do
t ”→“ 160x120dot ”… The method of reducing the image data itself to“ BMP (bitmap) ”→
"JPEG highest image quality" → "JPEG high image quality" → "JPE
There is a method of switching to “G medium image quality”, and FIG.
As shown in the figure, as the type of data compression for audio data, the sampling cycle is
k "..." and a longer sampling bit, "16bi
There is a method to reduce the number to "8" → "4bit".

In the compression / decompression circuit 15 in the above-described embodiment, the uncompressed data to be subjected to data compression in the data storage processing is determined by any one of the plurality of types of data compression methods or a combination of the plurality of types of data compression methods. The data compression processing is performed by selecting a compression algorithm whose compression rate has been changed to low or high according to the level of the frequency data of the least frequently accessed / oldest data in the data, and the data is stored in the storage device 13. Each data file corresponding to the required frequency can be compressed and stored smaller as the necessity is lower, and an empty area for storing a new data file can be secured accordingly.

FIG. 7 is a diagram showing a flowchart of replacement when data to be compressed is subjected to data compression processing at a compression ratio according to the access frequency in the data storage processing by the personal computer.

The replacement flowchart in FIG. 7 functions as step S6 'instead of step S6 of the data storage processing in FIG. 4, and according to this, the storage capacity of the data file to be stored is reduced by the storage device. 13, when the capacity of the free area is less than the minimum and the oldest data file of the access frequency among the uncompressed data that has already been stored, and the data file is compressed and overwritten and stored, the access frequency of the data file Is selected, the smaller the necessity of the data file is, the smaller the data file is, the smaller it is compressed and stored again, and a new free area is secured (steps S2 → S4 → S5, S6). ').

As a result, data can be stored more efficiently.

[0061]

As described above, according to the data storage device of the first aspect of the present invention, the data storage means for storing the data in association with the past update history of the data,
When storing new data, the data already stored in the data storage means is compressed according to the past update history associated with the data to increase the storable capacity.
In accordance with the necessity of the data, for example, the less necessary data is compressed to secure a storable area, and new data is stored.

According to the data storage device of the second aspect of the present invention, in the data storage device of the first aspect, the past update history is used as the frequency of use. In response, for example, data that is infrequently used is compressed to secure a storable area, and new data is stored.

According to the data storage device of the third aspect of the present invention, in the data storage device of the first aspect, the past update history is used frequency and storage date and time data. In accordance with the usage frequency and the storage date and time, for example, data with a low usage frequency and an old storage date and time is compressed to secure a storable area, and new data is stored.

According to a fourth aspect of the present invention, in the data storage device according to the second or third aspect, the data compression ratio of the data by the data compression means should be compressed. Since the data is changed in accordance with the past use frequency, for example, as the use frequency is lower and the necessity is lower, the compression ratio is reduced by a higher compression ratio to secure a large storable area, and new data is stored. become.

Thus, according to the present invention, it is possible to store data appropriately in response to the status of data already stored.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a personal computer including a data storage device according to an embodiment of the present invention.

FIG. 2 is an exemplary view showing a configuration of a file management area provided as a header of a storage device in the personal computer.

FIG. 3 is an exemplary view showing a configuration of an actual data area provided in a storage device of the personal computer.

FIG. 4 is a flowchart showing data saving processing by the personal computer.

FIG. 5 is a flowchart showing a data reading process by the personal computer.

6A and 6B are diagrams showing types of data compression for image data and audio data, wherein FIG. 6A shows a type of compression for image data, and FIG. 6B shows a type of compression for audio data. FIG.

FIG. 7 is a diagram showing a flow chart of replacement in a case where data to be compressed is subjected to a data compression process at a compression ratio according to an access frequency in the data storage process by the personal computer.

[Explanation of symbols]

 11: control unit (CPU), 12: key input unit, 13: storage device, 13a: file management area, 13b: actual data area, 14: work memory, 15: compression / decompression circuit, 16: display unit.

Claims (5)

[Claims] 1. A data storage means for storing data in association with a past update history of the data, and when new data is stored in the data storage means, the data is already stored in the data storage means. A data storage device, comprising: data compression means for compressing data in accordance with a past update history associated with the data and increasing storage capacity. 2. The data storage device according to claim 1, wherein the past update history is a use frequency. 3. The data storage device according to claim 1, wherein the past update history is usage frequency and storage date / time data. 4. The data storage device according to claim 2, wherein a data compression ratio of the data compression unit changes according to a past use frequency of the data to be compressed. 5. A data storage step of storing data in a storage device in association with a past update history of the data, and when storing new data in the storage device in the data storage step, A data compression step of compressing data already stored in the storage device in accordance with a past update history associated with the data to increase a storable capacity.