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Re: Problem using dd to clone a hard disk with bad sectors.

Subject: Re: Problem using dd to clone a hard disk with bad sectors.
Date: Sun, 19 Feb 2006 20:33:57 +0100
Am Donnerstag, 16. Februar 2006 11:31 schrieb Willard Van Dyne:
Hi all.

I'm trying to properly clone a 4.3GB (it's old, I know) hard disk
which unfortunately has a lot of bad sectors.
I am using Helix 1.7 as an operating environment, not mounting the
old drive at all.
I used the command:

dd if=/dev/hdb of=/mnt/hda7/image.dd conv=noerror,sync

My problem is that the md5 hash of the image file is different from
that of the original HD (acquired via the command: dd if=/dev/hdb
conv=noerror,sync | md5sum > /mnt/hda7/orig_disk_md5sum.txt)

Can anyone please enlighten me as to what I'm doing wrong?

Thanks in advance.

Do you know dd_rescue (debian pkg. ddrescue)? I never used it but it seems to 
be exactly suited for your kind of needs.

The MD5 maybe changes since md5sum does expect an actually working drive/file. 
On read errors it may not be as well behaved as dd. Just guessing...

-Christian

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