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Method for recovering deleted file of FAT32 partition

A deleted and file technology, applied in the computer field, can solve the problems of fast file access and difficult file recovery.

Active Publication Date: 2006-05-17
KINGSOFT
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AI Technical Summary

Problems solved by technology

The cluster size is determined when the partition is formatted. The larger the cluster size, the greater the wasted space, but the file access speed will be faster. Windows file systems generally select 16K or 32K by default when formatting a FAT32 partition. The size of 16K is mostly (generally determined according to the total size of the partition), so when the file in the FAT32 logical disk is deleted, if its data is located in the partition above 2G (case 1) or 1G (case 2), the recovery of the file become a problem

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  • Method for recovering deleted file of FAT32 partition
  • Method for recovering deleted file of FAT32 partition
  • Method for recovering deleted file of FAT32 partition

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Embodiment Construction

[0023] The method of the invention determines whether the data belongs to the file data by judging whether the file type matches the file type identifier in the disk data. Specific steps are as follows:

[0024] 1. Analyze the deleted file directory entries in the partition, and obtain the lower 16-bit information of the data start cluster;

[0025] 2. Obtain the extension of the deleted file;

[0026] 3. Read the disk position indicated by the lower 16 bits of the starting cluster in the file directory entry, and set the upper 16 bits to 0;

[0027] 4. Read the sector pointed to by the lower 16 bits of the starting cluster of the file and the assumed upper 16 bits, and read the sector;

[0028] 5. Determine whether the maximum sector number that can be represented by the partition has been exceeded, if so, skip to step 8;

[0029] 6. Judging whether the matching data matches the file type of the deleted file, if the matching indicates that the data may be the data of the f...

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Abstract

A method for restoring the deleted file in FAT 32 zone includes analyzing deleted file catalog item in zone to obtain low 16 bit information of data initial duster, obtaining expansion name of deleted file, reading disc position pointed by said low 16 bit and setting high 16 bit to be zero, fetching sector pointed by said low 16 bit and said high 16 bit, determining whether maximum sector number presented by zone is exceeded or not, judging whether matching data is matched to file type of deleted file or not, adding one on high 16 bit and remaining low bit unchanged, fetching sector pointed by low 16 bit and high 16 bit and then disengaging.

Description

technical field [0001] The invention relates to the computer field, in particular to a method for recovering deleted files. Background technique [0002] The FAT32 directory entry structure is as follows figure 1 shown. When Windows performs file operations, it locates file data according to this structure. When deleting a file on a FAT32 logical disk in the Windows system, first mark the first byte of the file name as a deleted flag, then modify the upper 16 bits of the file data start cluster to 0, and finally perform space release processing. The structure of the directory entry after file deletion in the FAT32 partition is as follows figure 2 shown. When a file in the FAT32 partition is deleted, the high 16-bit data describing its starting cluster is cleared to 0. Although the low 16 bits describing its data starting cluster are correct, in most cases, according to the residual directory entry after file deletion The data structure of the file, and the location of ...

Claims

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Application Information

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IPC IPC(8): G06F11/14G06F17/30
Inventor 涂彦晖邓振波陈睿
Owner KINGSOFT
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