Tutorial: how to properly erase and dispose of an old HDD or SSD

We have all been there: when the laptop gets real slow, with frequent crashes, and random errors... and when the clicking and tapping noise begins... that’s when you know one of your hard drives is failing, and it’s time to either perform one last ditch attempt to save it, or the last rites.

Hot to properly restore a badly corrupted HDD

The following assumes that backups of any data on your failing HDD exist at a separate location, and data on the drive is safe to dispose of.

The reason for an HDD drive to fail is most frequently a problem with the mechanisms inside. Hard disk drives are in constant motion when in use, which causes internal components to wear out over time. As an HDD ages, problems increase, such as data fragmentation, bad sectors, and a variety of issues that are likely to cause errors during regular operations. Performing a regular format of a badly corrupted HDD doesn’t always work, as the damaged sectors, although no longer available, still exist on the drive, at a very low level, and will simply be rewritten as new data is stored on the drive. In such case...

...do not Low level format!

Low level format is an “old school” procedure that restores an older HDD to factory, however, when low level format is performed on a modern SATA or SCSI HDD, two things can happen: in the best case scenario, the low level formatting will simply be skipped. The worst case scenario is that the drive will be rendered useless.

The modern way to completely wipe a HDD, is to perform what is known as a “zero fill”, which wipes and replaces every sector of a hard drive with zeros.

Zero-fill utilities abound, and some are even bundled with the range of utilities available in many mainboards BIOS. If the BIOS of your system does not provide zero-fill utilities, there are a number of free and commercial software utilities available, such as Blancco 5, and KillDisk Pro.

Depending on the size of the drive, zero-filling it could take several hours, especially if the drive is a little older. Also, for those particularly concerned with privacy and the possibility that someone could use advanced knowledge to retrieve data from a broken drive, zero-filling should be performed at least a few times, to ensure that all data is completely destroyed.

Unless there is some type of physical damage to the drive, zero-filling a HDD should restore it to a point where data can be stored and handled safely again, which should also result in a boost in performance, and less errors.

Completely wipe a SSD

The premise here is the extremely unlikely scenario in which a Solid State Drive becomes corrupted, or in the more likely scenario that the SSD is infected by a virus, which would warrant the near-total wipe. We use the words “near-total”, because wiping data from a SSD is never as simple as all that. SSDs don’t have sectors, like HDDs have, but rather “blocks”, that exist in memory chips.

While zero-filling is acceptable on HDDs, SSDs do not respond in the same way. In some instances, zero-filling a SSD will cause it to get stuck into a temporary reduced performance state, from which the drive might take a while to recover. Keep in mind, SSDs are built to be as low-maintenance as possible, and do not require extreme levels of resetting or formatting.

The ideal way to completely wipe a SSD, is through Secure Erase utilities. these utilities are often provided by the manufacturer of the drive in question, and will use TRIM, a feature that marks blocks of data to be deleted. Having said that, due to the nature of SSDs, even Secure Erase doesn’t not permanently destroy, or overwrites data, but rather makes it unavailable.

What to do when a HDD or SSD is beyond saving

If a HDD is beyond hope, and the only choice is disposing of it, remember: the data on it can still be retrieved, with due diligence, knowledge and the right tools.

To prevent a particularly dedicated hacker from gathering data, by playing Dr. Frankenstein with your trashed hard drive, write the following shopping list, and head down your nearest hardware store:

• 5lb sledge hammer
• red marker
• a big round wire nail
• a thick block of wood (don’t use a cutting board, or anything you might want to reuse later)
• thick safety gloves
• safety goggles
• a friend with a camera (You’ll get to do this only once, and it’s going to be fun)

Annihilation of a HDD

Using the red marker, draw a cross an inch away from the center of the drive, ideally where the round outline is on the top cover of the HDD.

Place the drive on a solid, thick, block of wood. This is also a good time to put on safety gloves and goggles.

Next, tell your friend to start recording, as you place the wire nail in position, at the center of the cross on the HDD.

Now, very carefully, tap the nail with the sledge a few times, to let it sink into the metal, deep enough to stand on its own. Once the nail is deep enough so as not to require fingers to keep it in place, it’s time to do your best impersonation of Thor, and drop the Mjolnir until the HDD is one with the nail. That should be sufficient to damage the drive badly enough to prevent most dedicated parties from retrieving data from the wreckage.

How to send a SSD to its doom

SSDs are not as easy to physically destroy as HDDs, because data is saved in many separate flash memory chips, and each one must be smashed to bits, to ensure that no data can ever be retrieved.

The boring, but safe solution, is to simply disassemble the SSD, expose the flash memory chips and smash each one with a hammer.

The fun, but more labor intensive way, requires the availability of a melting pot, or similar appliance capable of reducing any small metallic device into a glowing hot mass. Since, a variety of plastics and rubbers are likely to be part of the SSD, a well ventilated outdoor area is recommended, as well as qualified personnel who know how to properly operate a melting pot, without losing limbs, or consciousness.