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Comment Re:srm -v -z (Score 2) 91

Well, it confounds it at any rate. But completely filling the device's memory 33 times in a row is pretty likely to overwrite everything at least once or twice - even the hidden "failure reserve" space if it's included in the wear leveling (and if it's not, then it doesn't yet hold any sensitive data, so there's no problem). Guttmann's values may be irrelevant to today's storage media, but that many repeated rewrites of anything still mostly does the job.

If you were an engineer in charge of destroying data printed on paper, and you decided on shred then burn then stir the ashes in water, how many times would you repeat the cycle in order to be sure the data was destroyed? Hint: if your recommendation is greater than one (in order to be pretty sure), check your job title, because you're probably Dilbert's pointy-haired boss.

Drives today work almost nothing like the drives of 20 years ago. They don't paint bit-bit-bit in a stripe, they encode a set of bits in every pulse of the write head. Alter it a tiny fraction, and it becomes a completely different set of bits, one that error correction won't be able to overcome.

Old disks were recoverable because the mechanisms weren't precise, and the data was written with big chunky magnets to assure it was readable. All that slop has been engineered out on order to achieve today's remarkable areal densities. One overwrite is all it takes - as long as you're overwriting it all.

Comment Re:"overwrites all files" How Many Times? (Score 1) 91

My understanding is that in the old days of 20mb hard drives, storage densities were sufficiently low that even after one pass someone might be able to recover the data with at least some degree of fidelity. Once we entered the world of gigabyte drives, densities are so high that it's all but impossible to recover any data after even a single pass wipe

Comment Re:And then throw it in a fire (Score 4, Informative) 91

This.

What is the value of a used device? Compare that to the risk of the data on that device going to a malevolent third party.

I've had people saying "oh, look at all these hard drives, you should totally sell them on ebay and I bet you could get $10 apiece for them!" Adding up the time I would waste running DBAN or sdelete or whatever, and keeping track of which ones have been wiped, and double checking to make sure everything is really gone, it's not worth the time.

A big hammer and a punch, driven deeply through the thin aluminum cover and down the platter area, takes about a second and leaves nothing anybody would bother trying to recover. You can quickly look at a drive and say "yes, this drive has been taken care of", or "hey, there's no jagged hole here, this drive isn't destroyed." The aluminum cover contains the shards if the platters are glass. I don't care who handles them after destruction. There's no worries about toxic smoke. And if you have to inventory them before shipping them to a recycler, the serial numbers are still readable.

Smashing a phone wouldn't destroy the data on the chips, so a fire is a somewhat safer option.

Comment Re:Responsible party? (Score 1) 89

The outcome is fines paid by one part of government to another, but it does focus the leadership to get it right

Or discourage reporting any incidents. If losing a container of Anthrax means you get punished, then you have strong incentives to not tell anyone and hope you'll find it, rather than rise alarm and put the place in a lockdown.

Comment And done elsewhere (Score 1) 242

In Tucson 10%ish of the drinking water comes from reclaimed water (aka filtered sewage). Makes sense in an area with not a lot of fresh water resources. Also in those areas you can have different kinds. You can purchase a non-potable (not for consumption) water source for irrigation. Again, reclaimed water, but it undergoes less filtering and thus is cheaper. Plenty of larger places get a hookup to keep their watering costs down.

It is a very sensible way of doing things and you actually have more control of purity than water that comes out of the ground.

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