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I have a large .rar file inside partion D (Windows7/NTFS). It's corrupted due to bad sector (I think) and when I copy it to another place (External-HDD) the system freezes after 88% of progress. I even tried to copy it with my Ubuntu and same problem occurred. Also I tried chkdsk and it dosen't fix it.

I think my last chance is dump that file with a tool which ignores bad sectors and create a raw copy of it. Then I will repair the file with rar tools.

But I can not found a tool to raw dump a specific file. (In linux there is dd tool but it dumps all partition and I can not use it)

So, Is somebody know a tool to do a raw dump from a file?

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I find a commercial tool "Active @ File Recovery". It can copy a file to another place and ignore problems after a timeout. But it is commercial... –  M M. Nov 25 '12 at 12:29

2 Answers 2

up vote 1 down vote accepted

You can use dd to copy any file to anywhere (i.e. it's not limited to partitions). You can even ignore any read errors by using conv=noerror.

However, the "freezes" you observe are the disk retrying to read the bad sector and causes the read command to block. This will still happen with dd, but it will manage to continue after a timeout.

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Really?! How dd can use for a single file? Do you have an example? –  M M. Nov 25 '12 at 12:18
    
Just put a file name after the if or of parameter. The second line of the man page even says dd - convert and copy a file . –  billc.cn Nov 25 '12 at 12:20
1  
conv=noerror,sync would be better, since it will pad the missing parts with NULs. Even better would be using something like ddrescue (in the package gddrescue in Debian/Ubuntu, not dd_rescue) to clone the whole drive/partition and mount it for reading later. ddrescue is designed for recovery from damaged drives and will recover as much as possible by skipping damaged sections on the first pass. –  Bob Nov 25 '12 at 12:33

There is a russian software nscopy. It copies the file skipping BAD blocks. You may skip them with settings retry bad blocks reading=1 and number of passes to copy bad blocks=1 or you may try to copy them setting passes=0 for infinite :) I used it many times to rescue data from scratched CDs, DVDs, from HDDs with BADs. It's free! Try it!

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