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Re: [Bug-ddrescue] DDRESCUE examples in the GNU website + 1 kind questio

From: Antonio Diaz Diaz
Subject: Re: [Bug-ddrescue] DDRESCUE examples in the GNU website + 1 kind question
Date: Fri, 07 Oct 2011 18:17:30 +0200
User-agent: Mozilla/5.0 (X11; U; Linux i586; en-US; rv:1.7.11) Gecko/20050905

Hello Roberto,

Roberto Gini wrote:
thank you so much for your work with ddrescue.

You are welcome. :-)

why don't you add a specific example and sequence for the case "cloning a
drive with a lot of bad sectors" ?

Ddrescue can manage any number of bad sectors without special options. Of course an experienced user can shorten rescue time, but it depends on the drive's behaviour and I don't think any single example can cover all cases.

BTW, have you looked at the example shown here http://www.gnu.org/software/ddrescue/manual/ddrescue_manual.html#Algorithm

Additionally, I'd like to ask you why don't to implement a user definable *skip
ahead size amount* *and read backward* , in case of bad sectors

Ddrescue already skips ahead an exponentially growing amount depending on rate and error history. It totaly skips an unreadable 1.44 MB floppy in 8 seconds. I don't think the skip value needs to be made any larger.

Reading backwards is much slower than reading forwards. So jumps should not be too large, and all trimming is best done in a second pass.

P.S. there are some drives that are recognized nice by the BIOS, they do not
make bad noises but as soon linux or windows starts effectively to boot,
such drives (either if connected on secondary channels) hangs the windows
boot. It would be nice to have a ddrescue like tool interfacing directly
with the ATA interface. Do you know something similar out there? Have you
ever thought about this?

As far as I know, ddrescue doesn't run on windows so, as long as the drive does not hang the linux boot, this is not a problem. About using interfaces directly, I have already decided not to do it.

Best regards,

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