Wiping a HDD *Clean*

Hey guys,
One of my mates is selling off some of his old PC bits and he has an 20GB HDD that has some sensitive data on it. In short he wants a bit of software that can wipe the HDD so that the data cannot be retrieved (i.e erased to oblivion) before he selles it. Idealy he wants it to be free/share ware. Any ideas?


Low level format it?

Yep I go with wombles suggestion, just go to the hdd manufacturers website and download their lowlevel format utility it is completely free, for maxtor it is called PowerMax. Use and it sets the hdd back to factory settings, nothing is recoverable.



try Darik’s Boot N Nuke

it can be used from a floppy or a cd rom

If someone has decent data recovery tools, even a low level format won’t prevent them from recovering data. In order to prevent data recovery, it’s necessary to do multiple overwrites of each bit on the drive with varying bit patterns. There are some free utilities you can use to do this, like Active@ KillDisk. The free version of KillDisk only does a single pass, but you can run it multiple times if you want to really make data difficult to recover.

Active@ KillDisk conforms to US Department of Defense clearing and sanitizing standard DoD 5220.22-M. The most secure Gutmann’s data destruction method is also implemented. You can be sure that once you clean up with Active@ KillDisk, sensitive information is purged out forever.

Just don’t sell it to any enemy’s :bigsmile:

If you want the best then here it is…

It doesn’t matter all that much what specific program you use as long as it uses the Gutmann method. They all work the same way. I don’t see any reason why Swipe Pro would be any better than Darik’s Boot and Nuke, Eraser or Killdisk.

EDIT After reading a little more of the Swipe Pro webpage it seems that it doesn’t even allow you to use the Guttmann method, you can hardly label this as “the best there is”, it’s actually inferior in terms of security. Plus you have to pay for it while Eraser and Boot and Nuke are free.

A single Zero-fill, will take data below the recovery potential of any available user tools - in fact, probably already to the level that only forensic recovery is possible.

Modern PRML data channels are much closer to the threshold than the old “peak response”.

Any of the popular free tools should place the data in a condition where attempted recovery requires a LAB.

The main exception to low level format, being that some drives may not fully implement it.

I’d suggest eraser or DBAN, maybe also (or instead), a “data destructive” test from the drive maker, and then if you want to be really sure that it was well covered, format the drive and copy something unimportant over it - clipart, shareware archive discs etc. then delete or reformat (carelessly).

I’d consider a vital step of a secure erase, is to make the result look completely uninteresting.

The finer points, do depend on your requirement to put the data beyond “normal” recovery … which ONE overwrite most certainly does achieve, or beyond the most expensive recovery.

If I gave you a single erased drive, and you were not allowed to open the casing, I’d be confident you’d get nothing out of it.

To rehash, a lot of the old magnetic media erase patterns were designed for simpler encodings like MFM, and were designed to target any uncertainty around the transitions. other patterns were designed to resolve to lower or higher frequencies, and in modern ARLL encodings, will not resolve the same way.
I see Gutmann targets 3 ecodings, MFM, RLL (2,7) and RLL (1,7) - not sure if modern drives use encodings beyond 1,7.
The point is, that the advanced erasure is targeted at the traces that cannot actually be read by the drive itself, and there is a very big difference between the data being gone from the drive (as the drive sees it), and totally obliterated.

An example - do you use a paper shredder, and if so, is it a strip cut or a crosscut, or do you burn documents you want destroyed.

A drill always works :slight_smile: But if you want it to be useable afterwards, that Gutmann method sounds like a surefire way to destroy data. But a good poing was brought up: without opening the drive would you be able to recover anything? Doubtful.

Check out BCwipe at
it’ll wipe the hard drive to US Department of Defense standards and it is free!

Nemesys is right, the ideal number of times to wipe is 7 as a standard, at leats it is at my job. We got wiping software from the DOD (dept of defense) and we wipe 7x as a gov’t standard. Of course the more the better, but when you gotta do 200 machines a week wiping 20x is just not gonna make the cut. For a personal HDD I would just wipe until I had to sell.

Yeah but if you get something like cyberscrub or eraser you can use GUTMANN every time you delete something. I only use the GUTMANN level of wiping

I was with the Department of the Navy, NAVSEA Division running a small network before the NMCI transition to private contractors - We used the licensed (paid) version of BCWipe for file purging/deletion. The free version only does the entire HDD.