What Does Platter Mean?
A platter is a circular magnetic plate that is used for storing data in a hard disk. It is often made of aluminum, glass substrate or ceramic. A hard disk drive contains several platters that are mounted on the same spindle. The platters rotate when the hard disk is performing read/write operations; the rotations per minute depend on the hard disk model. The platter is very sensitive, and any contamination can often make the affected area unreadable, leading to data loss. The platter is capable of holding large amount of data.
Techopedia Explains Platter
A platter is capable of storing information on both sides. A head is provided between each platter to help in sensing and modifying the states of the platter. This results in two heads on each platter. Sometimes multiple arms are also provided, especially in the case of hard drives that use more than one platter for storing data.
The diameter of the platter among other factors determines the hard drive performance. The surface of the platter consists of a number of very small (<1 micron) magnetic regions, each of which comprises a single binary unit of information. The surface of the platter often has a mirror finish. The coating is done after it has been machined. During production, a special sensor is used to examine the surface of the platter to ensure that there are no defects.
When a hard disk fails physically, the platters may become scored owing to contact with the head and grinding on the surfaces. In such cases, data recovery can be difficult. During the recovery process, careful handling of the hard drive is strongly recommended because of the sensitivity of the platter. As a result, the recovery process is done in a clean environment.