The sector identification on a disk that the drive uses to locate sectors for reading and writing. Today's IDE and SCSI hard disks are low-level formatted at the factory. See format program.
"low-level format." YourDictionary, n.d. Web. 17 August 2018. <http://www.yourdictionary.com/low-level-format>.
low-level format. (n.d.). Retrieved August 17th, 2018, from http://www.yourdictionary.com/low-level-format