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Recover deleted x3f file ?

Started Aug 11, 2021 | Discussions thread
Joep van Steen
Joep van Steen Contributing Member • Posts: 576
Re: Recover deleted x3f file ?

ArvoJ wrote:

recovery software usually cannot know correct file length, it rounds that up

Hmm. File recovery either goes by file system meta data or by file signature.

By file system: if file is found then file size is known, no rounding of any sort.

By signature (RAW): Many tools in this category know the bare minimum about specific file types. They can detect start of file and most of time work with very simple assumptions about file size, either file ends where the next starts or fixed maximum size. So if file type is finicky about exact file size there lot's of room for error here, in fact it may result in un-openable files by definition unless files happens to end on cluster boundary.

Many (commercial file recovery tools can do both, often they will try file system reconstruction and in addition or of that fails do a RAW scan. RAW scanners in most tools know very little about specific file types. They 'know' about magic bytes at start of file , end of file (if file type specifies this at all), assume file stops where next starts. So very basic set of assumptions.

Ideally a 'raw scanner' knows enough about a specific file type to reliably determine file start and structure, and even is able to make some educated guesses about state/condition of the file (can I decode it?). Wouldn't it be possible to use some of the knowledge embedded in the X3F restore tool to create a RAW recovery scanner? With directory towards end of file it seems an ideal candidate for correct RAW recovery.

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Joep

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