Modern hard drives are low-level formatted at the factory for the life of the drive. A PC can not perform an LLF on a modern IDE/ATA or SCSI hard disk, and doing so would destroy the hard disk. Older MFM drives could be low-level formatted to extend the life of the disk, but modern hard drives no longer use MFM technology.
A low-level format is also called a physical format.
Floppy disks must also undergo low-level and high-level formatting, but these two are generally performed at the same time. On PCs, for example, the FORMAT command performs both a low-level and high-level format the first time a floppy is formatted.
(v.) The process of performing low-level formatting.