Here’s What Happens When You Delete Data

We bet you’ve gone through your old files at some point to clean things up a bit by deleting files from your computer. What if we told you that deleting those files doesn’t actually delete them—at least not entirely? Let’s go over how you can securely delete your files for good while you go about replacing hardware or upgrading your technology systems.

How Does Data Get Deleted?

The answer to this question is not so simple as having one answer. Really, it depends on the hardware. Storage media comes in two types: hard disk drives (HDDs), or solid state drives (SSDs). These two options function through vastly different methods:

• HDDs are mechanical devices that feature a spinning platter upon which a mechanical arm writes and overwrites data.
• SSDs save data via flash memory to chips, where it can be read very quickly, which also eliminates the need for any moving parts.

The type of device will play the biggest role in how to delete your data, and unfortunately for the SSD drive, it’s not a simple process.

Data Deletion Works in Different Ways

HDDs Are Far More Simple

With a hard disk drive, data deletion is simple. The arm is positioned over the disk to effectively rewrite the data stored on it. It’s remarkably simple.

SSDs Are More Complicated in Comparison

Unlike HDDs, SSDs use flash data that can’t just be overwritten. The existing data must be erased before anything can be added back to it. This takes time and can slow down the process.

This is why SATA-capable SSDs can use TRIM.

TRIM is a command that helps your SSD know which data blocks can be erased. It’s important for ensuring that the longevity of the drive is preserved and that the processes are as efficient as possible. SSDs use an internal operation called “garbage collection” in which valid data is moved from a block with data that is to be deleted. TRIM adds to the process by ensuring that deleted data cannot be copied; this process ignores various data points during garbage collection that streamlines the number of write cycles the SSD needs to go through.

This is a background process, meaning you can work while the data is being deleted knowing that you’ll have storage space to handle whatever comes your way. With the Windows process, TRIM is automatically enabled, and it effectively replaces Disk Defragmenter.

Is Your Data Truly Gone?

We wish we could give you a more definitive answer to this question, but the unfortunate truth is that it’s complicated. SSDs will “lie” to the operating system in use in regards to the data blocks available, meaning that different cells age at the same rate. This process, called wear-leveling, is done to preserve the longevity of the SSD. This also means that certain blocks might not be as trimmed as you might expect. TRIM also involves some buffer space that might keep some recent data stored on it, too.

So the Answer is Yes… But Also No

Your files will be deleted, make no mistake, but the security of those deleted files might not be so sure. We realize that sounds a little nutty; the fact remains that you need to be very careful with how you dispose of devices, especially if you are planning to donate or resell them.

Ask Us About the Hardware Refresh Process

You always want to upgrade to reliable technology, but if you’re not careful, you can undo progress in this direction. That’s where we come in. If you have a drive or device you need to wipe, we can help you with this process so that it can get done in an efficient and timely manner, all without putting your data at risk. To learn more, reach out to us at (02) 8825-5555.