Tech Random's, Tips and Tricks

Understanding the Differences between Wiping and Formatting Your Hard Drive.

One of the questions I get most often, is what to do with old hardware. With this question, the primary concern is how to format the drive before they discard it. Most people know they need to format their drive, but they don’t know that just formatting the drive leaves it vulnerable to data recovery solutions, and who knows what kind of person ends up with that hard drive once it’s discarded. This process can get complicated, especially if they plan to format, then give it away to a relative. With recovery disks most often lost, and Microsoft licensing requirements, SSD vs HD, this can get tricky.

I tend to use the following metaphor when asking the person what they truly want to do. I have found there’s a 50/50 split between those who want to format, and those that want to wipe the hard drive.

Imagine your cutting chicken on a table, afterwards you need to clean the table. You have two options, hot water, or clorox. When you wash the table with just hot water, it doesn’t do much at all except wipe any excess off the table. Think of this as formatting your drive. When you format your drive, the files are marked as “deleted”, telling the controller to allow new files to overwrite those files (hense, you can now place items on your bacteria ridden table). However the file is not touched in this case, that is, until a file gets over-written. Because of this, file recovery solutions can look at the drive and find that file, even if its marked as deleted. This is true for HDD’s and SSDs.

Wiping a HDD
If you plan to reuse the drive, you can use a program like ERASER, by attaching the drive as a secondary drive, or using an adapter like this one.
If you don’t plan to reuse the drive, the absolute way to verify the data is gone, is to destroy the drive. There are a bunch of ways to do this, disassembly, shredding, smelting. The Eraser program is still very effective. If you have a degausser, that effectively destroys all data on the drive, to include the HDD PCB (Printed Control Board). Degaussers don’t work on SSD’s. If you plan to shred your SSD, make sure its 1/2 inch or less to verify the memory chips don’t slip thought the teeth.

Wiping an SSD
Wiping an SSD is more difficult than an HDD. You can use Eraser, and run repeated passes to get the desired results, but that wears down the SSD, reducing the lifespan. Now this might not be an issue with a home environment, its still concerning.
Currently, the best way to verify that data is destroyed on an SSD, is to destroy the drive itself.

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