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Date: Fri, 7 Dec 2012 20:10:55 -0700 (MST)
From: Warren Block <wblock@wonkity.com>
To: Chuck Burns <break19@gmail.com>
Subject: Re: 9.1-RC3 LiveCD missing features
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On Fri, 7 Dec 2012, Chuck Burns wrote:

> dd if=/dev/zer of=/dev/ada0
>
> ^^^ There's your "badblocks" program.  Any hard drive made in the last decade 
> have been self-remapping..

That should be /dev/zero.  And this will be very slow, going one 
512-byte block at a time.  Using a 64K or 128K buffer (bs=128K) will 
speed it up tremendously.