The hard disk is an internal data carrier of the computer. They differ in the size of case, there are 2,5" (mainly for notebooks) and 3,5" hard disks available. Hard disks consist of thin magnetic discs which are written by a writing/reading head. Depending on the information (binary data has only two values: one or zero), the magnetic particles are polarised in one or the other direction.






Hard Disk im deutschen Lexikon
Hard Disk in het nederlandse encyclopedie