On a hard drive, the smallest unit that can be accessed is a sector. Hard disk platters are spherical disks that are split into tracks that circle the disk. The tracks are lengthier as they travel from the disk's center outward, so the tracks near the disk's edge have more sectors than the tracks closer to the disk's center. Zoned-bit recording is the term used to describe this variation in sectors per file.

Huge files can occupy hundreds of storage sectors. The likelihood of the file being illegible is high, even if one of these sections becomes damaged. A disk maintenance software might be able to repair damaged data, but it cannot repair bodily harm. "Bad sectors" are described as physically ruined sectors. While some bad sectors on your hard drive may be detected and ignored by your computer, other bad sectors may stop your disk from functioning correctly. Another compelling argument for regularly backing up your data