A Hard Disk Drive (HDD) also hard drive or hard disk is a non-volatile. The harddisk is the primary storage unit of the computer. A harddisk consists of a stack of disk platters that are made up of aluminum alloy of glass coated with a magnetic material.
The surface of a disk is divided into imaginary tracks and sectors. Tracks are concentric circles where the data is stored. These tracks are numbered from the outermost ring to the innermost ring, starting from zero. Disk sectors refer to the number of fixed size areas that can be accessed by one of the disk drive’s read/write heads, in one rotation of the disk, without the head having to change its position. An intersection of a track and a disk sector is known as track sector.
Each sector is uniquely assigned a disk address before a disk drive can access a piece of data. In order to make the disk usable, first it must be formatted to create tracks and sectors. The track sectors are grouped into a collection known as cluster. It refers to the basic allocation unit for storage on a disk.
The operating system, software titles and most other files are stored in the hard disk drive. The hard drive is sometimes referred to as the "C drive" due to the fact that Microsoft Windows designates the "C" drive letter to the primary partition on the primary hard drive in a computer by default.While this is not a technically correct term to use, it is still common. For example, some computers have multiple drive letters (i.e. C, D, E) representing areas across one or more hard drives.