Wiping data from a hard drive - what to do?

OK, so I’ve got my former drive that I’m now turning into a slave. I used the disk utility to blow the partition and then used XP to format it into NTFS. Anything else I should do?

Do a Gutmann scan with Tolvanen’s Eraser utility.

Are you asking from a usability point of view or a security one? If all you want to do is free up the space so you can use it again, what you’ve done is all you need to do. If you’re once again able to read and write into it from Windows, you’re fine.

If you’re worried about security, however, find a data wiping utility that’ll go over the entire disk and “wipe” the data. They usually do so (I think) by writing random bits over every part of the drive and repeating the process a few times.

That is, if you have sensitive data on there – such as financial records or proprietary 3rd party materials owned by an employer – that you don’t want lingering, which is what I assumed from the thread title.

If you did a full format, that is enough. The only thing more secure than that is destroying the drive. The overwriting utilities are only needed when you erase files from a drive.

Sorry for the multiposts, but I have to mention, the Gutmann scan will take a long, long, long time. For all intensive purposes, as they say, a DoD7 scan will probably suffice. For your average hard drive, you can do one of those overnight.

Are you sure about that? My understanding is that reformatting the hard drive will not prevent data from being recovered.

On further thought, my answer is a little incomplete. If you format to the same OS, there is a chance that a high-level program could gleem something from it. If you do a full format to another OS (Win98 to Win2k for example), the disk will be clean.

I fail to see the point in “overwriting with carefully selected bit patterns.” Think in terms of a sand castle, if you want to make sure that no one knows there was a sand castle, are you best off to form sand people with the same sand, or just flatten the sucker? Same result, but one is a bit more cost effective.
I would be worried about any tool like this as being a virus when it is so clearly advertising to people who aren’t technical.

This is what the State of Virginia has to say about reformatting and the removal of data from a hard drive:

Sorry, quick hijack: How do you sample a dog, anyway?

Eraser isn’t a virus. But don’t take my word. Check it out yourself. I would expect anyone to do that before downloading and using it.

Eraser overwrites the drive, or sections of it, with layers of random bits. So yes, it essentially flattens the sandcastle. Then it takes the sand and rescatters it, anywhere from 3 to 35 times.

Bark, howl, do what you like,
but if you’re gonna growl, just growl into the mic.

Reviews of Eraser. Old and from Tolvanen’s site. Do your homework on your own, of course. I think you’ll be happy with what you find.

I’m going to have to ask for a cite on that. Even if you do a full format and change partition tables (which I assume is what you mean), there is still data left over on the drive, it’s just that the computer doesn’t “know” it’s there. If you direct the hard drive to read at a certain point, then you may be able to recover the data. Even if that sector has been written over, there’s still a minute chance of it being recovered, due to the fact that hard drives don’t write in the exact same physical place every time. Sometimes, it’s off by just a little bit, so technically the 1s and 0s are still there, they just need to be read by highly sensitive devices.

With that said, the most common method for securely wiping hard drives is filling it up with random data, deleting, and repeating (IIRC) 7 times. Either that, or completely destroying it.
Oh, and S_t_D, I hate to nitpick but you did something that really irks me sometimes. It’s “all intents and purposes,” not “all intensive purposes.”

Your right, my info is a bit out of date. Recovery software has made some advances since I last looked into this. That being said, I think most commercial software only has a chance if the drive is formatted and then not used again. Even a minimal amount of use is going to stymie most off-the-shelf software (no cite, only my opinion). The software used by the intelligence agencies, if we believe the reports, would likely have some success until the write-erase-write etc. method.

This is what Eraser (and similar utilities) does. Dept of Defense standards require 7 passes. Gutmann scan does 35 passes, which is why it can take days for today’s relatively large drives.

I know. That’s why I added “as they say”. I should have kept in mind that people on this thread might not know what I do for a living. :smack:

“It’s a joke, son. You’re built too low to the groun’, the fast ones are goin’ ova ya head, boy.” -Foghorn Leghorn :wink:

You’re right, even.

Secure Deletion of Data from Magnetic and Solid-State Memory

Perhaps this is a hardware issue, but as a programmer I am at a loss.

If I zero out all data, I see no point in going back over it to re-zero it seven times or even a second time. Similarly, I see no point in randomizing the data if I can zero it out. Zeroing is a faster and easier process as well as being safer, since theoretically random data can be restored without true-randomization.

Not arguing with what you are saying, rather I am asking if anyone knows if there is any hardware basis for performing such an operation?
For instance, if you write something with a pencil on paper, you are better off to draw random scribbles over it than to erase, due to the imprint caused by the pencil on the paper and the fact that the eraser will probably not get everything. If there is some sort of magnetic equivlent for this, then the seven times thing makes sense.