The modern equivalent to low-level formatting is “zero-filling”, whereby you replace all data on your hard drive with arbitrary zeros or other characters, making that data deleted and unrecoverable. However, there are equivalent processes that carry out similar functions. Today, modern (SATA and ATA) hard drives are low-level formatted upon manufacture and can’t technically be low-level formatted again in the same way as old MFM drives used to be. It was used in the past to get rid of all existing data on old MFM hard disks permanently – useful if you had sensitive data that you wanted gone forever, were selling your hard drive, or if you had a severe virus, such as a boot-sector virus, which couldn’t be removed using the standard formatting process. Low-level formatting formats your hard drive past the point of no return because it wipes all existing sectors on the physical surface of your drive rather than just on the filesystem. An important thing to know is that the meaning of “low-level formatting” has changed over time, and this efficient formatting method has largely been replaced today by something known as “zero-filling.” Here’s everything you need to know about this process and the tools you need to do it.

Seagate disk formatting software