There exists a variety of tools doing the repairs or data extraction from a given file type, like DOC/DOCx, ZIP and so on. The file recovery is actually one more recovery type, similar to photo recovery which was mentioned earlier.
The file recovery software may be useful if the file got damaged because the file data was not fully written to a drive, say, because of the power failure during the write. Or because the program working with the file crashed before completing the write. Should this happen, the actual file content (or a worthwhile part of it) might still be written to the file.
Practically, it is pointless to apply such software to "fix" files which data recovery software found on the damaged drive. The data recovery process, such as the one used to recover RAW file system, typically either gets OK files, or the files are fully damaged, not containing any trace of original data. If the files do not open in their respective programs after a data recovery, this means most certainly no subsequent fixing applied to these files can restore them because the useful data is just not there.
Saturday, February 12, 2011
Monday, January 10, 2011
Why are only the thumbnails are sometimes recovered?
More often than not while recovering digital photo files, typically off a memory card, the small image previews, called thumbnails, are recovered successfully, while high-resolution images themselves are damaged.
This behavior is explained by "file fragmentation". The fragmentation is said to occur when the file is stored on the disk in more than one non-contiguous blocks. The sketch explaining the process can be found at the Photo Recovery Limitation page.
The FAT or FAT32 filesystem is most likely to be used on a memory stick or a thumb drive.
Once the file gets erased on the FAT filesystem, the only information that is still available is how to locate the 1st fragment. Any subsequent blocks cannot be recovered.
Thumbnail is not large and placed at the beginning of the file, therefore the thumbnail is usually extracted OK, and still the high resolution image is garbled. Of all the data recovery types, this limitation affects mostly digital photo recovery and unformat on FAT.
This behavior is explained by "file fragmentation". The fragmentation is said to occur when the file is stored on the disk in more than one non-contiguous blocks. The sketch explaining the process can be found at the Photo Recovery Limitation page.
The FAT or FAT32 filesystem is most likely to be used on a memory stick or a thumb drive.
Once the file gets erased on the FAT filesystem, the only information that is still available is how to locate the 1st fragment. Any subsequent blocks cannot be recovered.
Thumbnail is not large and placed at the beginning of the file, therefore the thumbnail is usually extracted OK, and still the high resolution image is garbled. Of all the data recovery types, this limitation affects mostly digital photo recovery and unformat on FAT.
Subscribe to:
Posts (Atom)