Low Level Format

Hard disks must be formatted twice before they can be used for the first time. The first of these two is the Low Level Format, which sets the interleave factor and prepares the disk for a particular type of disk controller. Generally, this is performed by the manufacturer and should not be of concern for the end user. Performing a Low Level Format erases all data on a disk, which differs from performing a High Level Format where only directories and such are erased.