Re: Overwriting a 4096 byte sector harddisk drive with random data
On Thu, 21 Jul 2011 19:47:44 +1000
yudi v <yudi.tux@gmail.com> wrote:
> Hi
>
> I need to write random data to a partition before encrypting it.
> Suggested way is to use urandom:
>
> #dd if=/dev/urandom of=/dev/sda2
>
> What is the use of operand "bs" in the following case? I see the above
> command executed as follows sometime:
>
> #dd if=/dev/urandom of=/dev/sda2 bs=1M
>
> For the hard drive I got, should I use the following command:
>
> #dd if=/dev/urandom of=/dev/sda2 bs=4096
>
> >From what I understand, the first command above will write data in
> >512 byte
> blocks, the second one in 1MB blocks, and the third in 4096 byte
> blocks. Right?
> I am a bit confused about the usage of this operand in this case.
>
That is correct. They will both do effectively the same thing,
however, the version with a larger block size will probably run faster
on a modern machine.
--
rbmj
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