Re: [Bug-ddrescue] recover single files from NTFS partition?

[Ariel]

On Tue, 19 Sep 2006, RD wrote:

> Everything I read about ddrescue seems to imply trying to recover whole 
> partitions. Can I also use it to recover single files from an otherwise good 
> NTFS partition?

Sort of.

> Can I mount the NTFS partition and "ddrescue /mnt/ntfs/my_mail_file logfile"? 
> I understand the file may be not be laid out in one piece on the disk and may 
> be fragmented.

Well, that's the question: can you mount the NTFS partition? If you can, 
then yes you can use ddrescue on a single file.

But if you can't mount the NTFS partition, you will need to copy the 
entire thing somewhere else where you can run repair tools on it.

> In other words, I guess my real question is: does ddrescue copy disk blocks 
> one after the other, or when given a file, does it just ask the filesystem 
> module/driver/whatever to return the relevant blocks which it can read?

Both actually. Normally it's run on a physical device, and it just copies 
blocks one after the other.

But if you run it on a file it will still copy blocks one after the other 
- only in this case the OS/filesystem will redirect each block to it's 
actual location on the disk. (This is what a FS normally does.) But that 
requires a functioning filesystem.

        -Ariel