PC Hardware in a Nutshell, 3rd Edition

Low-Level Formatting

Low-level formatting a hard drive lays down the tracks and sectors that will be used to store data and also embeds servo information that the drive head positioning mechanism uses to locate those tracks and sectors. Modern drives are low-level formatted at the factory, and cannot be low-level formatted by the user.

You sometimes need to low-level format a drive, or at least do something that resembles a low-level format. The three most common situations that require formatting a drive down to bare metal are the presence of a virus that cannot be eradicated by a logical format or by repartitioning the drive, a corrupted partition table that cannot be corrected by using a partitioning utility, and a drive that is beginning to develop bad sectors.

For all these situations, the solution is to pseudo-low-level format the drive with the maintenance utility provided by the drive manufacturer. Although these utilities do not do a true low-level format, they write binary zeros to every accessible bit on the drive, wiping all data and partitions from the drive. These utilities also typically have a sector-sparing function that allows them to detect bad sectors and swap them out for a spare sector, returning that drive to its factory-fresh, error-free state.

If you need to do a low-level format of your drive, download the latest version of the low-level format utility from the manufacturer’s web site. Create a DOS-bootable diskette, and copy the low-level format program ...