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How Do I Nuke My Hard Drive?

Molinaro said:
Write 0 to all, then 1, then 2, then 3, up to 11111111..11 in binary for whatever size you're writing, then 0s again.
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If the sequence of numbers written is known then it is possible to figure out the original data that was overwritten (within certain percentages of likelyhood).

For example, if a bit was a 1, and is rewritten to a zero the magnetic field doesn't go all the way to what is identified as a zero. if you read the strength back, and know that it was supposed to be modified to a zero you can figure out which bits were 1's prior to the change and which were 0's. The more passes made the more likely the original field gets wiped. If the bit pattern of the overwritten data is known, it makes it easier to figure out what the original data was and more passes are needed to obliterate the original data.

Your example useses a lot of passes, so it would work, but it would take a long time.

3 passes of reasonably random data would be much faster and most likely just as effective.
 
Thanks for the info Kevin and I agree: If it is that important a sledgehammer might be a better solution.

Still very interesting.

LLH
 
In the National Guard we have to remove the HD and send it to be destroyed before getting rid of the computer. When I worked on a NATO base we had a incinerator. The military dosent use these military grade shredders so I dont know how good they really are. If you ever had important information on it its not worth the risk when you can replace it for peanuts. Why not just donate it without a HD?

There is a chance the charity will just sell it to a 2nd hand shop. It very well could end up in the hands of a super evil super geek.
 
When I was googling on 'hard drive permanent file removal' or such, I came across the web site of someone selling their nuking tool.

He had an anecdote on his front page about, surprise: guy donates computer to charity, and then huge purchases start showing up on his debit card. Had someone obtained his hard drive from the charity? Yes, they had.

When it doubt... don't give them the hard drive. They can use one of their own, or a new one donated by a hardware company.
 
It's worth taking a hard drive apart, if only for the magnets. (I admit to being a magnet freak).
And the disk itself makes a super pocket mirror.


OK. OK. Big nerdy kid.

If you did have any data on there you don't want loose, like the firing codes for a polaris missile or something, wrecking the drive is the only absolute 100% way to be sure. If you don't have a screwdriver, a hammer and chisel will do.

At the OS level, why would this not be enough?- Format the drive. Reinstall the OS. Write a script that simply copies itself (S1.vbs, S2.vbs etc) to the drive. Make it the right size to nearly fill one sector, so there's no unwritten space. Then let it run till the disc is full?
I wonder how long a script would take to fill a 60Gb drive?
 
jnelso99 said:
From what I've heard, just overwriting the data once will not do the trick, especially against folks like the NSA.
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This isn't that big a deal. I gave the thing to a charitable recycling shop that we've donated to several times. If the person who winds up with my computer could do half the things you guys are talking about, he wouldn't be shopping there.
 
Soapy Sam said:
At the OS level, why would this not be enough?- Format the drive. Reinstall the OS. Write a script that simply copies itself (S1.vbs, S2.vbs etc) to the drive. Make it the right size to nearly fill one sector, so there's no unwritten space. Then let it run till the disc is full?
I wonder how long a script would take to fill a 60Gb drive?
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Nope, not secure at all. There's a ton of space on most HDs that is reachable that is not necessarily erasable by any standard OS tools or methods. Zapping a disk needs to hit stuff like PC BIOS storage areas (sometimes up to 2MB), multiple boot blocks, track 0 space, bad block space, etc, etc (i.e. where the virii live...).

As said above, you need a really low-level formatter - one that literally re-applies the blocking information, rather than just rewriting the existing block contents. Or drive a stake through its heart!
 
Nope, not secure at all. There's a ton of space on most HDs that is reachable that is not necessarily erasable by any standard OS tools or methods.-Zep

Is it likely that any of Beady's dirty pictures are stored in those areas though?
Surely anything stored by the OS can be overwritten by the OS?

Beady. Keep the damn thing as an internet terminal. That way you don't have to worry about malware, just reformat it twice a week.
 
Soapy Sam said:
At the OS level, why would this not be enough?- Format the drive. Reinstall the OS. Write a script that simply copies itself (S1.vbs, S2.vbs etc) to the drive. Make it the right size to nearly fill one sector, so there's no unwritten space. Then let it run till the disc is full?
I wonder how long a script would take to fill a 60Gb drive?
Click to expand...

That'll work fine for data you're most worried about (i.e. your personal data). You could even write a vbs script to generate random numbers and write them to a file on the disk, then you don't have the issue of known bits being written to the drive. Heck it's probably slightly faster since the drive heads don't have to move to read data before copying it.

However the secret is always multiple passes. Make sure you do this at least 3 times.

Oh yeah, and if you plan on tossing a drive in the trash you should probably do this too. But then, I shread my junk mail as well as my regular mail.
 
I give up: do you have some Windows licensing issue here? ie why go through all this "kill HD" thing and make it basically un-unusable to a charitible organzaition, who would now have to go BUY Windows to use your "free" gift?

Why not just delete everything and then do a defrag for ex?
 
bigred said:
I give up: do you have some Windows licensing issue here? ie why go through all this "kill HD" thing and make it basically un-unusable to a charitible organzaition, who would now have to go BUY Windows to use your "free" gift?

Why not just delete everything and then do a defrag for ex?
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If you mean not unistalling windows, that would be illegal if Beady wants to use the same copy elsewhere.

There are also security issues, but unless Beady has been keeping very compromising data on his PC, I wouldn't think that that would be a problem.
 
Smike said:
If you mean not unistalling windows, that would be illegal if Beady wants to use the same copy elsewhere.

There are also security issues, but unless Beady has been keeping very compromising data on his PC, I wouldn't think that that would be a problem.
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Look, guys, let's get a grip. The place I gave it to, they do their own nuke and reinstall, anyway. In fact, the computer will probably get a good servicing and upgrading, and be indistinguishable from a braned-new, if very low-end, machine. It will probably also sell for less than $100, because that's about the income-level of people who shop there.

As for Windows, it'll have a brand-new, perfectly legal, install. I don't know how, but these recycling shops are tied into a supply network that no one like us normally sees. I'd be willing to bet that MS donates licenses to these places. We got to know this particular place pretty well during our decade of unemployment.

FWIW, I wouldn't know how to buy a computer that didn't have Windows already installed. My big problem with the new one is figuring out what installed stuff I don't need and how to get rid of it.
 
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In that case, either delete the stuff you don't want the charity people to see, or if there's loads of it, format the hard drive, using a bootdisk as I suggested earlier.
 
LordoftheLeftHand said:
Who actually buys windows products?
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For the computer I just got rid of, I bought something called Office Suite, so I could get MS Word, rather than have to use the "Microsoft Works Word Processor" that came pre-installed. Weird thing was, I could have paid $400 for Word by itself, but the Suite bundle was $150. The even weirder thing was that Word was the only part of the bundle I ever used. Upshot was that I paid $150 for a bundle of MS products that I didn't want, so I could have a program I would have had to pay $400 for, all on its own.

I understand MS makes money on deals like this.
 
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