Drive recovery using Linux??

Andrew Zajac arzajac at
Wed Mar 5 17:58:12 UTC 2008

>  The problem I'm wondering about (the image from dd is almost done) is
>  the filesystem...the mount example is trying ext3, when I tried mounting
>  the drive physically fdisk couldn't determine the existence of a
>  partition table, and no filesystem.
>  Any way to extract if there was a filesystem and it's just damaged?

If dd completed without error, then that's pretty good.  Tools like
rr_rescue and dd-rhelp (or the even better gnu dddrescue) are used to
make an image of a failing drive while ignoring read errors.  If dd
completed on its own, then the drive is probably okay.  Why it's
partition table is gone is a mystery.  Could the DVR have gone haywire
and formatted itself?

If you are confident that the image you made is intact, you can try
working on the physical drive to fix the partition table.  I say this
because you imaged the whole device.  You cannot mount the whole
device, but only the filesystem on the first partition of the device.
I don't know what kind of partition table or filesystem your DVR uses.

Testdisk or parted can detect and add partitions found on the disk
that are not part of the partition table.  You can try that.

If you are unable to detect or guess what partition goes where, you
can always try to data-carve the files from the raw image or device.
Photorec and foremost are very good at doing that.   You can data
carve a lot of the data on a disk even after it has been formatted.

Good luck.
Andrew Zajac

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