Another use of the versatile word head.

A head is an electromagnetic device that can be used to read, write, or erase data on magnetic media. There are three generic types:

              Bits Per   Tracks Per     Areal
Head Type       Inch       Inch        Density

Monolithic      8000        900          106
Composite      12000       2000          108
Thin-Film      25000       3000          109

Heads can be found on many devices, such as tape drives, hard drives and floppy disk drives.