OT: Hard Drive wipe

[OaklandGB]

It would appear from the comments, that physical destruction has the lead in this race, followed by fire. Perhaps both are a form of physical destruction arrived at by different means.

I think I'll avoid trying magnets as some of the short comings that have been pointed out, such as case shielding to whatever degree, seem to make sense.

At the end of the day, maybe crushing, breaking up of the internal discs, then dumping them into the burn pile, or melting them with a torch, seems to be the end of any readable data, residual or otherwise. Additionally, scattering the burnt bits over a wide area would insure against any "big brother" conspiracies from being realized.

All great comments by the way.

[macona]

Now for the really bad news: Flash memory (SD cards, SSD) cannot be erased. Every write occurs at a new location, with the old location marked as invalid.

What? No, this is not true at all. That would mean you would fill a drive once and it would be useless after. Its not ROM.

[thin-woodsman]

Nope, not ROM. And yes, I exaggerated a bit. Basically you have to contend with the wear-leveling built into the card/drive, which is what causes updates to be written to new locations. The idea being that, because flash memory supports only a limited number of writes, every cell in the memory has to be written to before a previous cell can be overwritten. This is a gross simplification of course, and there is stuff like TRIM which attempts to address this (and does work to some extent), versus the strategy of flash card/drive manufacturers to over-provision a card (e.g. selling 64 GB of memory as a 32 GB card) ... there are a lot of competing forces at work. Attempts to find bulletproof ways to erase flash memory (e.g. "Reliably erasing data fro flash-based solid state drives", Usenix '11) have basically come up empty. This makes me classify SD cards and SSD drives as "cannot be erased" even though, in theory, they can be.

https://www.usenix.org/legacy/events...papers/Wei.pdf

[SLK001]

I think I'll avoid trying magnets as some of the short comings that have been pointed out, such as case shielding to whatever degree, seem to make sense.

There is no magnetic shielding in a commercial hard drive. Magnetic shielding is very heavy and very expensive (it needs very high "mu" material).

[wmgeorge]

Subject pretty well beat to death. Pun intended, take your hammer and/or torch and destroy including SD and USB sticks. Sorry OaklandGB you said the same thing.

[JRouche]

I am not one for smashing and especially burning. Im a F'in Tree hugger Men, I dont burn plastic.

So, I guess I am going use the houngan core drill bit to press a few holes into the bottoms of my laptops. Should take care of any info. Not that there was anything LOL.

Ok this will be cathartic.. Had these for 20 years. JR

[rkepler]

If the drive can be mounted you might use Darik's Boot-n-Nuke: https://dban.org/ It'll boot then selectively overwrite whole drives.

[AD5MB]

when I worked in a secure area, the security guys said no commercial or freeware solution works. they take them apart and read the individual platters. I just cut mine in half with a chop saw and move on to other things.

[Mike72]

I'm surprised no one mentioned the demagnetizer, like the ones used on parts removed from the magnetic chuck.

[danlb]

I'm surprised no one mentioned the demagnetizer, like the ones used on parts removed from the magnetic chuck.

You mean Degaussing, as mentioned in post #27??

Degaussing works to a certain level, but the CIA / NSA has techniques to read tracks and can differentiate between places on the disk where 0s and 1s were written.

I once had a box if 8 inch floppy disks in the drawer of my wood computer desk. A while later I started to notice that some of my disks had gone bad. Some diagnostics showed only part of each disk was erased. The programs were still usable if the data was not written on the outside tracks on one edge.

Further analysis traced the problem to the fact that I had I moved the desk next to the TV. The high voltage transformer was just inches from the disk holder.

But I would not count on degaussing if you want 100% trustworthy wipe.

Dan

[SLK001]

But I would not count on degaussing if you want 100% trustworthy wipe.

If you truly want a 100% trustworthy disk wipe, you must use the hammer magnet. Bring the hammer magnet into close proximity of the hard drive many times (10 times is enough). Then sweep up the parts and dump them into the trash.

[john b]

Is that 10 times with an 8oz or 8lb magnet

[nickel-city-fab]

I use a shell script with DD to write /dev/random to the entire disc. Then it makes another pass with all 0's. Then it makes another random pass. then it writes all 1's. Finally, it does a last pass with /dev/random again. Such wipes are nearly unrecoverable, according to the FBI. It's how they do it.

If I don't want to save the drive and reuse it, I just get the oxy-acetylene and make slag. Be sure to pick out the magnets first.

[JRouche]

I'm surprised no one mentioned the demagnetizer, like the ones used on parts removed from the magnetic chuck.

I think in the most part degaussing sets work very well. I have a commercial unit, and I made a hap hazard one for my walker mag plate. A degaussing set they probably didnt have. I dont know. I had to make the PS for this big pig 24x12 plate. I am glad I took a chance and stuffed in a degaussing circuit just cause. The big Walker plates are still grabby after the ac is shut. Hit the de-mag button I mounted on the control and yep.. Everything dropped, even all the tiny lil slivers :} JR

Ps. Meaning put a de-mag on your electromagnetic chucks.. JR

[Noitoen]

The best is to keep the drive and send the rest to be recycled or, don't store anything useful