However, notebook drive platters are commonly made of glass, and shatter in a quite unrecoverable manner when sufficient force is applied.
For hard drives DBAN (or similar) is sufficient to prevent data recovery and allow disk reuse. No-one has been able to convince me that any form of recovery is possible from a modern drive that has been overwritten - the data densities are too high and the controllers don’t allow the sort of intertrack residual domain snooping that may have been possible on older drive types. However, DBAN is slow and it’s use requires absolute adherence to protocol to ensure all drives are processed correctly - too many companies have failed spectacularly at this process, so many people are wary of using disk erasure and reuse.
[QUOTE=wikipedia]
On the other hand, according to the 2006 NIST Special Publication 800-88 (p. 7): “Studies have shown that most of today’s media can be effectively cleared by one overwrite” and “for ATA disk drives manufactured after 2001 (over 15 GB) the terms clearing and purging have converged.”[1] An analysis by Wright et al. of recovery techniques, including magnetic force microscopy, also concludes that a single wipe is all that is required for modern drives. They point out that the long time required for multiple wipes "has created a situation where many organisations ignore the issue all together – resulting in data leaks and loss. "
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For military/intelligence use, the ability to destroy all data beyond recovery immediately mandates the use of builtin degaussing or thermite systems. Thermite (when suitably applied) also has the added side effect of rapidly destroying data resident in RAM (even when power has been removed RAM can hold data for seconds or even minutes).
Specific degaussers are available for hard drives, but leave the drives unusable (the degausser destroys the servo track that controls the head position). Just a big magnet is not sufficient.
Finally, physical destruction destroys the drive (by bending, shredding, penetration or heat). Theoretically, data could be recovered off a large piece of platter using scanning probe microscopy - however, this is extremely slow, and would only provide file fragments. Someone would have to be incredibly motivated and resourced to do this. Disk shredding services can provide a mobile onsite destruction service, and allow easy verification of destruction. The OPs hydraulic press/bender would be sufficient (and probably cheaper), but there are speed and safety considerations to be had - how long will it take, and will those involved be safe while doing so.
If it is an ongoing concern, buy a hard drive shredder. They aren’t really all that expensive. For one time deals, on sensitive data, hire a contractor to physically shred them.
It’s an on-site professional machine shop with experienced machinists, so I don’t expect safety to be a big issue. And I think the bender will be faster than drilling; the ram+anvil pair are six feet long, so we can line up maybe 14 drives at a time for a single stroke. We should be able to wreck 150 drives in twenty minutes or so.
When our company was going to replace a few hundred PC`s way back when, they thought the only economical and confidential way was to crush.
My suggestion - they eventually followed: donate them to a charity which would resell them. A group of us IT people volunteered to do the disk wipe and factory reformat after hours. We were company employees so they could have a higher level of trust it would be done properly. The charity gave us tax receipts for our time (IIRC at $50 per hr back then, nothing too unbelieveable) since we were professionals and this was our day job too. The company got a tax receipt and community goodwill, nothing went to waste. Eventually, the charity made about $30,000 on the sale, back when real PC`s were over $1000 and $400 for a used PC and monitor with Win98 was a heckuva deal.
DBAN is mentioned above. Set up a room with a dozen PCs or more at a time, run DBAN, and hopefully somewhere you have a factory install disk or partition, get the assembly line going. I don`t think you need to worry about the NSA doing a data recovery unless your vusiness is very interesting.
[QUOTE=Machine Elf]
It’s an on-site professional machine shop with experienced machinists, so I don’t expect safety to be a big issue.
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Sounds like a plan, so long as the machine operators are prepared for the (typically external) circuit boards to shatter and shoot shrapnel in unpredictable directions while the drives bend.
Just be sure one or more people get an accurate count of drives to be crushed vs drives that have been crushed to ensure no drives have wandered away.
We cleaned up the data center a few months back and ran into the same issue. Normally, I’d use a Debian Nuke disk, but a lot of the stuff we had wouldn’t even boot. Plus it’d take too damn long for the amount of drives I was dealing with.
I went with a FatMax. I set the drive on the floor, covered it with a towel and gave it a solid whack on each side with the scarey claw side of the hammer. This would totally wreck the circuit board and more often than not, pierce the casing and wreck the platter. After a few, you tend to learn where the sweet spot is, and can hit the platter on the first whack.
As suggested earlier – Hammer, hard drive, bored teenage son of the company president.
I had 35 hard drives to destroy. You don’t know what a look of delight is until you give a hammer and a box of drives to a 13-year-old boy, and tell him to smash them.
