▷ How to format a hard drive at low level

What is low-level formatting and what is it for?

Low-level formatting, unlike high-level formatting, is an operation performed directly against sectors of the disk. This operation mitigates the file system layer and goes directly to the underlying storage. Normally, operations against storage devices are performed using a logical abstraction layer called a file system. Humans do not think in terms of bits and sectors, but in terms of file names and possibly file sizes. This is exactly what file systems do, plus a few other things like maintaining file-directory relationships, optimizing read and write, maintaining operations integrity, and more.

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In Linux, for example, you have file system drivers, responsible for this type of work, called ext2, ext3, ext4, reiserfs, and others. When you create a partition, then you format it with some file system. The choice will dictate what you can and cannot do with the underlying storage, which will now be exposed to the user. This is the so-called high-level format, because you don't care what kind of hardware you have. You don't really need to know anything except that there is a hard drive that can now hold things.

High-level formatting can be thought of as a kind of map of possibilities: it tells the kernel, which manages all the useful operations of the hard drive, where the data can be stored and in what way. This means that if you are reusing a hard drive, the old data that has previously been stored on the device may still be available in its original form. Of course, this old data is meaningless as the new file system at the top doesn't know about it and will freely overwrite the segments during normal operations. But if you're only using 1-2% of your total storage, theoretically there could be entire blocks of old data that could be read, bypassing the file system, so to speak.

This is considered by some to be a privacy risk, as accidentally gifted, stolen, or reused hard drives may contain accessible old data. In most cases, determined and experienced users can extract randomly stored pieces of data from the storage media.

Low-level formatting is a procedure where data is written directly to the storage medium, bypassing the file system layer. It doesn't matter if the hard drive has one partition or more, NTFS or BTRFS or anything else. You are using the device driver, which can be IDE or SCSI or SATA or others, and you are writing data to physical sectors. Most importantly, the low-level format will be written to each and every bit on the storage device, making sure that old data is destroyed forever.

Performing a low-level formatting operation is known as a single pass format. Some security consultants, experts, and paranoids may recommend that you make three or more passes, to ensure that no trace of old data can be recovered. Statistically, this is a total exaggeration.

Low-level formatting should be performed with extreme caution. You must be absolutely sure that you are going to perform this operation against the correct storage device. A wrong choice can lead to total, absolute and unrecoverable destruction of your critical data. What you should do for low-level formatting is grab the old disk and connect it to your machine. The disk may already have a partition table with multiple partitions, file systems, and even data. It is also possible that your system automatically mounts these partitions.

Low-level formatting with DBAN

For low-level formatting you can use a small tool called DBAN that can be used with any brand of hard drive and will erase all existing data with three passes. That means it will erase and overwrite existing data three times to make recovery impossible. Please note that this tool is designed to work with magnetic hard drives (SATA and ATA), not SSDs.

To use this tool, you will need to create a bootable flash drive. The best tool to do this is Rufus that we have already told you about before.

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When you have configured all the options correctly, click "Start." Wait for the process to finish, and you'll have a bootable flash drive that contains your low-level formatting tool. ”

Then restart your PC and press F12 repeatedly until your PC asks you which device you want to start from. Select the flash drive and the formatting tool should open. From now on, you should be very careful because this is where you have the power to delete data on your hard drive forever.

Once the application loads, it will ask us for the mode of use that we want, we give it to the manual mode by pressing Enter and it will show us a list of all the hard drives that we have installed.

We move with the direction arrows to the desired hard disk and press Enter, after that we only have to press F10 to start the low-level formatting process. We just have to let the app work.

Low-level formatting with HDD Low Level Format

HDD Low Level Format is another tool that we can use to do low-level formatting. The advantage of this application is that it works within Windows, making it easier to use. The drawback is that you cannot format the disk. hard that contains the operating system.

We can download the portable version of the application that does not need installation. Once downloaded we open it and choose to use the free mode. The application will show us the list of hard drives we have on our PC, select the one that interests us and confirm the low-level formatting operation. We just have to let the tool work.