JP2007122339A - File restoration method, file restoration program, and recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restore file data which are hoped to restore to an accessible file even when the file data in question are overwritten by another file data. <P>SOLUTION: When a maximum block number is not found at a step 507 and it is found that main data are destroyed by overwriting the file data which are hoped to restore by another file data, the step advances to a step 510, where it is decided whether or not sub-data, such as a thumbnail, remain. When they remain, the file to be restored can be restored to the accessible file by copying the sub-data to the main data or replacing the sub-data with the main data at a step 511. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a recovery method of a file recorded on various recording media such as a storage device such as a memory card or HDD, a magnetic disk or an optical disc, a file recovery program, and a recording medium storing the program.

  2. Description of the Related Art Conventionally, there is software that recovers a file when a file is deleted, misformatted, inaccessible, or the like in a storage device or storage medium for some reason such as an operation error. The existing file recovery software (Photo Rescue) final data, R-Studio data rescue, etc.) is a hard disk or removable media (external HDD, memory card, etc.) that has been accidentally deleted or formatted incorrectly. Files can be retrieved from media that has been lost, or media that has become inaccessible for some reason, and can be restored so that it can be accessed again.

  FIG. 8 is a schematic diagram showing a configuration of a medium formatted by the file system. The media is divided into three areas: MBR, PBR, FAT, Root Directory, and data area. MBR and PBR indicate the division of the area in the medium. In the FAT, data connection information (stored in which block and in what order) stored as a file is stored. The Root Directory stores a file name, a file size, and the first file number in a block in which the file is stored. The data area stores a large number of blocks containing data. A sequence of block numbers from the first block to the last block is called a FAT chain.

FIG. 9 is a flowchart showing an example of a recovery processing procedure of general file recovery software. First, in the process 101, a file that can be normally accessed without any problem in the cooperation between the directory entry and the FAT chain is converted into a file, and is deleted from the target after the next process. The process 102 restores the file by attaching a file name to data in which only FAT chain information that is not referred to from the directory entry (for example, the file name or size is unknown) remains. The data area filed here is also deleted from the target after the next processing. The process 103 analyzes the file format of the data (such as a header) remaining in the unused data area, converts the data having connection into a file, and restores the file (see, for example, Patent Document 1). The process 104 stores the file that has been filed on another medium. Alternatively, if the data is stored as it is on the same medium, the FAT chain and the directory entry are corrected.
JP-A-8-227372 (page 3-4, FIG. 3)

  However, since the file recovered by the above file recovery software is a file that has been deleted, if you write data after deleting another file on the media, the file data you want to recover is overwritten with another file data. In such a case, the conventional file recovery method as described above restores a file that cannot be accessed at all even if it is recovered, so that the file cannot be recovered normally.

  The present invention has been devised in view of the above circumstances, and an object of the present invention is to restore a file that can be restored to an accessible file even when the file data to be restored is overwritten with another file data. A method, a file recovery program, and a recording medium storing the program are provided.

  In order to achieve the above object, the present invention provides a file recovery method for recovering a file when a recovery target file has secondary data in addition to main data, wherein at least a part of the main data of the file is destroyed. Detecting that the file area for storing the sub data is normally left, and detecting that the file area is normally left, the sub data of the file area is detected. Copying the main data into a file.

  In the file recovery method for recovering the file when the recovery target file has sub data in addition to the main data, the present invention detects that at least a part of the main data of the file is destroyed. And a step of detecting that a file area storing the sub data is destroyed, and a step of replacing the sub data with main data to form a file.

  As described above, in the present invention, when data is written after deleting a file, at least a part of the main data of the recovery target file is destroyed, for example, the recovery target file data is overwritten with another file data. However, if the sub data remains, the file that can access the recovery target file can be recovered by copying the sub data to the main data or by replacing the sub data with the main data. . If the main data of the file is destroyed and the file cannot be recovered as it is, but the file has sub data such as a thumbnail in addition to the main data, and this sub data remains Can restore a file that can be accessed using this sub-data.

  According to the present invention, at least a part of the main data of the file to be recovered is destroyed, but if the sub data remains, the sub data is used to transfer the file data to be recovered to another file. Even if it is overwritten with data, it can be restored to an accessible file.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of an information processing apparatus according to an embodiment of the present invention. An information processing apparatus (such as a personal computer) includes a CPU 1 connected to a bus 10, a main storage device (RAM) 2, an external storage device (such as an HDD or a memory card) 3, and a console device 4 such as a display.

  FIG. 2 is a schematic diagram showing an example of the structure of an Exif file having a compressed thumbnail stored in the external storage device 3. The Exif compressed file 11 has areas of SCI, APP1, DQT, DHT, SOF, Compressed, Data, and EOI, and APP1 is an APP1 Marker, Length, Exif, TIFF Header, Oth IFD ExIF IFD Ist IFD 1st It has a JPEG Thumbnail area, and JPEG Thumbnail contains a compressed thumbnail. Further, the compressed thumbnail 13 has areas of SCI, DQT, DHT, SOF, Compressed, Data, and EOI. 3 and 4 are diagrams for explaining the meaning of these words.

  Next, the operation of this embodiment will be described with reference to the flowchart of FIG. When a file repair command is input from the console device 4, the file repair program of this embodiment as shown in FIG. 5 loaded in the main storage device 2 is activated to control the CPU 1 and read from the external storage device 3. Repair files that can no longer be exported.

  First, the CPU 1 sets the smallest FAT unused block (sector) number to n in step 501, and then reads n blocks (sectors) from the external storage device 3 in step 502. Further, in step 503, n is JPEG. It is determined whether it is the first data of. If it is not the top, in step 504, n is incremented by 1 and the processing returns to step 502 to search for the top data of JPEG. If it is the head data, in step 505, the JPEG data read for the next JPEG data search is stored in the memory area of the main storage device 2.

  Next, in step 506, after n is incremented by 1, in step 507, it is determined whether or not this n is larger than the maximum block number. Otherwise, in step 508, whether or not this n is a FAT unused block is determined. If not, the process returns to step 506. When a FAT unused block is found in step 508, in step 509, this n block is read from the external storage device 3, and it is confirmed whether the data is consistent with the stored JPEG data. As a result, if there is no consistency and the data is different from the retained JPEG data, the process returns to step 506, and if the data is consistent with the retained JPEG data, the process returns to step 505. When the confirmation is completed up to the final data of JPEG by these processes, the file is restored. The processing so far has been performed, but if n is larger than the maximum block number in step 505, that is, if the final JPEG data is not found by the maximum block number, the Exif compressed file shown in FIG. In the case where 11 data areas have been overwritten, it has been difficult to repair by the conventional recovery process.

  However, in this embodiment, when the final JPEG data is not found up to the maximum block number in step 507, the process proceeds to step 510 to determine whether the APP1 or thumbnail data of the Exif compressed file 11 has been confirmed. If YES in step 511, the JPEG file is restored from the APP1 data or thumbnail data, and the process ends. If APP1 or thumbnail data cannot be confirmed in step 510, the file cannot be recovered and the process is terminated.

  Here, how to restore JPEG from APP1 data or thumbnail data in step 510 will be described below. (1) If APP1 can be confirmed, that is, as shown in FIG. 6, if the main data of the Exif compressed file 11 is destroyed but the area of the compressed thumbnail 13 remains normal, this area is used as the main data. By replacing it and making it into a file, it can be processed into a file that can be accessed normally. In this case, the original thumbnail 13 is replaced with main data, and the file is restored as a file having no thumbnail information (no APP1).

  (2) When the compressed thumbnail in the APP1 marker remains normally, that is, when the main data of the Exif compressed file 11 is destroyed as shown in FIG. The file is processed into a file that can be normally accessed by copying the compressed thumbnail to the main data and making it a file while leaving this area. In this case, the original thumbnail 13 is copied as main data, and the file is restored as a file having thumbnail information.

  According to this embodiment, in a recovery target file having sub data in addition to main data, the file data to be recovered is overwritten with another file data, and even if the main data is destroyed, the sub data If a certain compressed thumbnail 13 remains in a normal form, or if the area of the APP1 marker 12 remains normal even if the main data is destroyed, it can be restored as an accessible file.

  In addition, this invention is not limited to the said embodiment, In the range which does not deviate from the summary, it can implement also with another various form in a concrete structure, a function, an effect | action, and an effect. For example, in the case of a file having sub data in addition to a JPEG file, the same effect can be obtained by similarly applying the present invention.

It is the block diagram which showed the structure of the information processing apparatus which concerns on one Embodiment of this invention. FIG. 2 is a schematic diagram illustrating an example of an Exif file structure having a compressed thumbnail stored in the external storage device illustrated in FIG. 1. It is a figure explaining the meaning of the phrase in an Exif compression file. It is a figure explaining the meaning of the word in an APP1 marker. It is a flowchart explaining the file recovery method of this invention. It is a figure explaining the process of step 511 shown in FIG. It is a figure explaining the process of step 511 shown in FIG. It is the schematic diagram which showed the structure of the medium formatted with the file system. It is the flowchart which showed the example of the recovery processing procedure of the file recovery software marketed.

Explanation of symbols

1 ... CPU, 2 ... main storage device (RAM), 3 ... external storage device (HDD or memory card, etc.), 4 ... console device, 10 ... bus.

Claims (9)

In the file recovery method for recovering the file when the recovery target file has sub data in addition to the main data,
Detecting that at least part of the main data of the file is destroyed;
Detecting that the file area for storing the sub data remains normally; and
When it is detected that the file area remains normally, the step of copying the sub data of the file area to the main data to form a file;
A file recovery method comprising: In the file recovery method for recovering the file when the recovery target file has sub data in addition to the main data,
Detecting that at least part of the main data of the file is destroyed;
Detecting that a file area for storing the sub data is destroyed;
Replacing the sub data with main data to form a file;
A file recovery method comprising:   3. The file recovery method according to claim 1, wherein the file is a JPEG file. In a recording medium recording a file recovery program for recovering the file when the recovery target file has sub data in addition to the main data,
Detecting that at least part of the main data of the file is destroyed;
Detecting that the file area for storing the sub data remains normally; and
When it is detected that the file area remains normally, the step of copying the sub data of the file area to the main data to form a file;
A recording medium on which a program for causing a computer to execute is recorded. In a recording medium recording a file recovery program for recovering the file when the recovery target file has sub data in addition to the main data,
Detecting that at least part of the main data of the file is destroyed;
Detecting that a file area for storing the sub data is destroyed;
Replacing the sub data with main data to form a file;
A recording medium on which a program for causing a computer to execute is recorded.   6. The recording medium according to claim 4, wherein the file is a JPEG file. In the file recovery program for recovering the file when the recovery target file has secondary data in addition to the main data,
A function of searching for head data from the main data storage area of the file;
A function of determining whether data sequentially connected to the head data can be searched;
A function of detecting that at least a part of the main data of the file is destroyed by not being able to search the sequentially connected data;
A function to detect that the file area for storing the sub data remains normally;
When it is detected that the file area remains normally, a function of copying the sub data of the file area to the main data to form a file;
A file recovery program characterized by causing a computer to realize the above. In the file recovery program for recovering the file when the recovery target file has secondary data in addition to the main data,
A function of searching for head data from the main data storage area of the file;
A function of determining whether data sequentially connected to the head data can be searched;
A function of detecting that at least a part of the main data of the file is destroyed by not being able to search the sequentially connected data;
A function of detecting that a file area for storing the sub data is destroyed;
A function of replacing the sub-data with main data and creating a file;
A file recovery program characterized by causing a computer to realize the above. 9. The file recovery program according to claim 7, wherein the file is a JPEG file.

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