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The best method to prevent others from reading the data on hard drives is to destroy the drives physically: a sledgehammer is a cheap and effective tool to prevent the data from being read again. Since many types of hardware, including hard drives, contain toxic materials, it'd be a good idea to take them to some responsible e-waste recycling services.

There's a lot of info on the web about diverting e-waste from landfills. There's also plenty of discussion on destroying data on hard drives. But I have not found info on ensuring the data on the drives has been destroyed before giving them to the e-waste recycling services. I afraid that a hard drive that has been beat up too badly becomes difficult or impossible to handle by the recycling services.

Is it possible to satisfy both the environment and my own privacy?

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3 Answers 3

up vote 3 down vote accepted

A first method is to open up the old hard disk, and extract the platters. Hard drives are usually closed with screws, so it can be unscrewed; beware, though, that it is customary for hard disk vendors to hide the screws under stickers (a disk is sealed and letting the air in can kill it, so vendors want to prevent inquisitive customers from unknowingly breaking their disks).

The data is on the platters; the rest of the disk can be sent to recycling... except if that is a hybrid drive, where data can be both on the platters and in the Flash chip. Removal of the said chip can be done, but this assume that you access the logic board and reliably recognize the Flash chip.

With this method, the recycling issue is not solved, but reduced to the platters only.


Another method is degaussing. A hard drive degausser will destroy the magnetically stored data by applying a powerful magnetic field on the disk (either a big fixed one, or a smaller alternating one). This makes the disk unusable (because the disk tracks are also destroyed) but preserves its physical integrity, making recycling as easy as it can be on a "normal" disk.

There again, Flash chips may resist degaussing, so SSD and hybrid drives will be a problem.

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I've had numerous discussions with forensic analysts and security IT folk, and the general consensus is that DoD wiping your drives is sufficient to destroy your data. Smashing a hard drive may be fun and cathartic, but from the research I've done, not necessary in many cases.

DoD wipe your devices and then take it to an e-waste recycling facility.

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Unfortunately, this kind of logical wiping can be applied only if the disk still works -- and a failed disk is a common reason for having an old disk to dispose of. –  Tom Leek Oct 7 '13 at 20:18
    
Excellent point - one I wasn't thinking of when posting! –  DKNUCKLES Oct 7 '13 at 20:20

If the disk is functional, doing a couple of passes writing random data is more than sufficient to completely prevent anyone from gaining any data form the drives. No individual, research organization, or spy agency has ever said otherwise when it comes to spinning disk modern HDDs. There is no need for many passes, weird write patterns or other funky stuff (read the epilogues from the paper by the guy who actually did legitimate research attempting to recover this data (his name might sound familiar if you've seen ridiculous 35-pass methods for wiping drives))

Gutmann's paper

"with the ever-increasing data density on disk platters and a corresponding reduction in feature size and use of exotic techniques to record data on the medium, it's unlikely that anything can be recovered from any recent drive except perhaps a single level via basic error-cancelling techniques."

SSDs are another matter since wear leveling blocks certain blocks form being written to, effectively leaving the data on those blocks and prevents them from being overwritten by most common technologies. I cannot speak to effective deletion of all blocks on SSDs.

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