Sector

A hard disk term.

A hard disk is formatted to hold data, which means the smooth surface of the hard disk has had a certain magnetic structure imposed upon it. If you could see this structure it would look a bit like a dartboard. Lines would radiate out the centre whilst concentric rings divide up the disk. The area between two rings and two radial lines form a 'sector'. A bit like the 'double 20' area on a dartboard.

A sector is the basic chunk of magnetic material that typically holds 512 bits of 'user data' plus some extra data bits that help control the spinning hard disk. A group of sectors form a 'cluster' which is also described in this glossary.

2020-10