Re: [Bug-ddrescue] image size problem, urgent please

[Robert Backhaus]

On 25 June 2012 00:30, mambi <address@hidden> wrote:
>
> Dear all,
>
> I have a fat32 lba external usb disk that suddenly stop working. I followed
> the ddrescue manual instructions and up to a point it recovered aprox 32GB
> but then stop recovering information. Probably that's all the relevant
> information I want to recover.
>
> The image is recognized as a 32gB FAT 32 (LBA) partition. The MBR is
> corrupted and there is a good backup one. Unfortunately it seems it is not
> recoverable the information inside because the image is too small 32GB
> instead of 320GB which is the size of the external drive.
>
> I am wondering if there is a way to expand the image to 320GB so I can copy
> the backup boot sector and recover the "useful" data in those 32GB.
>
> Please answer as soon as you can. Lots of work in this drive that is no
> where else at the moment.
>
> Rodrigo
> --
dd bs=1K seek=320M if=/dev/zero of=your_file count=1

Should do it. Check the dd syntax for yourself, of course, and always
work on a copy. Should be instant if your output file is on a
filesystem that supports sparse files.
You should be able to do the same with ddrescue: you want to skip
320GB of your output file and write 1 block of zeros.