How To Wipe Hard Drive Safely

[silverbirch]

Hi everyone

I have a friend who is a psychotherapist and needs to wipe the hard drive of her old computer before either selling it, or disposing of it.  It's important the data is removed so it cannot be retrieved.  I thought a live Linux CD could be used for this, but my googling says an expert could still retrieve the files.

Can anyone help with other methods of clearing the drive.  Dban was another method mentioned, but the information from the website isn't very good.  The computer is an HP Pavillion I think, running WinXP.

Many thanks.

[T6]

there is many ways to do this securely and without destroying the hard disk

dariks boot and nuke on www.dban.org will do that job nicely

there was a article in zdnet with other options but is old

basically any app that can overwrite the entire hard disk surface 7 times is legally doing the job you want in a impossible to undo way

others say that you need to do this 34 times but i think that it is paranoic

this is another method on this old article

http://www.zdnet.com/blog/storage/how-to-really-erase-a-hard-drive/129

another article talking about dban

http://ask-leo.com/how_should_i_erase_my_hard_drive_before_i_give_it_away.html

more information on another article

http://www.webopedia.com/DidYouKnow/computer_science/2007/completely_erase_harddrive.asp

[silverbirch]

OK - thanks for that.  I've read most of that stuff and found leo's easiest to follow.  So will offer to attempt the dban method for her.  It seems simple the way he explains it - just a matter of following some prompts.

Many thanks.

[T6]

glad to help 

[Neal ManBear]

I've used dban before. It did an excellent job.     

[aguila]

+1 to DBAN, a liveCD.

Uses methods used by the CIA or military. www.dban.org iirc

[Just18]

The livecd can do it quite easily ......  use the command   dd   to write zeros to the complete drive.

After that nobody can recover anything from it, as it is all overwritten.

Code:

dd  if=/dev/zero  of=/dev/sdX

where 'X' is the drive in question.

It does take some time ....  depending on the size of the drive amongst other things.

regards

EDIT:
           In case anyone wishes to question the above, all I would ask is that you try to find ANY incident of any files being recovered from a drive that was wiped in such a fashion, and provide a link.
  Other, multiple wipes methods, may have been prudent many many years ago, when dealing with the likes of floppy diskettes and such.
As far as I am aware there is no recorded and verified incident of even one file being recovered from a modern HDD which was written completely with zeros.

[djohnston]

As far as I am aware there is no recorded and verified incident of even one file being recovered from a modern HDD which was written completely with zeros.

+1
The Great Zero Challenge Remains Unaccepted

[Neal ManBear]

That is correct, as far as I know. Writing the drive to all zeros is what dban does, I believe.    

Following Just18's advice would be the quickest/easiest solution, IMO.    

[AS]

The livecd can do it quite easily ......  use the command   dd   to write zeros to the complete drive.

After that nobody can recover anything from it, as it is all overwritten.

Code:

dd  if=/dev/zero  of=/dev/sdX

+1, for performance reason add the option bs=1M, will overwrite using 1MB chunks instead of one byte block at a time  

EDITED!

[Just18]

The livecd can do it quite easily ......  use the command   dd   to write zeros to the complete drive.

After that nobody can recover anything from it, as it is all overwritten.

Code:

dd  if=/dev/zero  of=/dev/sdX

+1, for performance reason add the option bs=1M, will overwrite using 1MB chunks instead of one byte at a time 

Quite probably .......  but I have never had a change to see what the performance gain would be ......  do you have any info on that when using the  dd  command on a complete drive?

Thanks 

[AS]

The livecd can do it quite easily ......  use the command   dd   to write zeros to the complete drive.

After that nobody can recover anything from it, as it is all overwritten.

Code:

dd  if=/dev/zero  of=/dev/sdX

+1, for performance reason add the option bs=1M, will overwrite using 1MB chunks instead of one byte at a time  

Quite probably .......  but I have never had a change to see what the performance gain would be ......  do you have any info on that when using the  dd  command on a complete drive?

Thanks  

I have tried and used it in the past, but don't have available data right now, the difference is mostly because of the overhead introduced by the higher number of write calls when using a small block size, like can be a 512 byte block of a classical hard disk, number that will be 2000 times higher in that case compared to a 1M block size.

AS

EDIT: "will overwrite using 1MB chunks instead of one byte block at a time"

[Just18]

The livecd can do it quite easily ......  use the command   dd   to write zeros to the complete drive.

After that nobody can recover anything from it, as it is all overwritten.

Code:

dd  if=/dev/zero  of=/dev/sdX

+1, for performance reason add the option bs=1M, will overwrite using 1MB chunks instead of one byte at a time  

Quite probably .......  but I have never had a change to see what the performance gain would be ......  do you have any info on that when using the  dd  command on a complete drive?

Thanks  

I have tried and used it in the past, but don't have available data right now, the difference is mostly because of the overhead introduced by the higher number of write calls when using a small block size, like can be a 512 byte block of a classical hard disk, number that will be 2000 times higher in that case compared to a 1M block size.

AS

EDIT: "will overwrite using 1MB chunks instead of one byte block at a time"

I can understand that it could use less PC resources ...  less write instructions, but would not have considered it would be any quicker to complete ....  or at least not much quicker.

But, as I said, I never had the opportunity to test it.

[pupthai]

"either selling it, or disposing of it"

Remove the drive and use a 3lb hammer, then a trash bin.  Selling it with no or a new drive or dispose of it as a donation minus a drive, but dd would work too for most of us.  It is a write off for a professional.

I don't even have that kind of Data and have never let go of a PC with a drive or disposed of a worthless PC with the drive in it.  It would appear now that many politicians don't even return State PC's with the drive in them ether, they pay for the drive and keep or hammer it - it is in many State laws that they can do that.  You never really know about media and what might have hidden and protected itself in there, if it ever ran on a win box would you really trust it again?

[silverbirch]

Okay - a question, just so I'm sure.  From what I read here it was a matter of following options:  http://ask-leo.com/how_should_i_erase_my_hard_drive_before_i_give_it_away.html BUT I could instead at the prompt enter the code:
dd    if+/dev/zero    of=/dev/sdX   (with or without ) bs=1M

Thanks again.