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Re: OT: Can Reformatting A Hard Drive To ext3 Destroy All the Data On It?

On Fri, May 29, 2009 at 4:39 AM, Ambrogio <fn050202 interfree it> wrote:
> Il giorno ven, 29/05/2009 alle 14.52 +1200, Clint Dilks ha scritto:
>> > dd if=/dev/zero of=/dev/youbettergetthisright bs=1M
>> >
>> If you want to be really sure you need to do the command above several
>> time or use software like
>> http://www.dban.org/
> /dev/zero is not the right device to use.
> Better is /dev/random or /dev/urandom
> But they are not speed

See the mkfs.ext3 man page for:
  "    Check the device for bad blocks before creating the file
system. If this option is
       specified twice, then a slower, read-write test is used instead
of a fast read-only test. "

Once the device is formatted the paranoid can fill it with files
containing random
and other bit patterns (0xa5a5, 0x5a5a, 0x0000, 0xFFFF..).

Solve the dev/random dev/urandom slow part by reusing a modest block of
random bits over and over to build large and small files that fill  the disk.
Finish with lots of copies of your favorite Fedora.iso image file.

The cautious should use vendor tools to reformat the disk...
Special attention to the partition table should be given so 'spare'
or 'hidden' partitions are dealt with.

The very very paranoid should cut the drive into bits with a cutting torch
since bad block spares or unused flash ram might contain sequestered
bits that might  get recovered.

        T o m   M i t c h e l l

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