What is Low Level Formatting(LLF)?
Each platter in a disk drive is organized as tracks and sectors. Each sector contains header and trailer information as well as error detection (CRC) data in addition to the actual user data field. When a disk is manufactured the platters are blank (no sector layout). Before shipping, a special command (usually not documented) is issued to the drive to cause it to lay down the sector headers, blank data fields and good CRC. Also many data patterns may be written to each sector to check for media errors. Any sectors with errors are put into the “manufacturer’s defect list” and the drive remembers not to use those sectors in the future. Later, after the drive is shipped, a user may decide to “Low Level Format” the drive if he is having problems, or wants to start with a “clean slate”. This is done using the SCSI FORMAT command via a special utility usually supplied by the host adapter manufacturer (usually in the on-board BIOS). Some side effects of doing a LLF: • The logical block size
