A computer keyboard is a peripheral modelled after the typewriter keyboard. Keyboards are designed for the input of text and characters, and also to control the operation of the computer. Physically, computer keyboards are an arrangement of rectangular or near-rectangular buttons, or "keys". Keyboards typically have characters engraved or printed on the keys; in most cases, each press of a key corresponds to a single written symbol. However, to produce some symbols requires pressing and holding several keys simultaneously, or in sequence; other keys do not produce any symbol, but instead affect the operation of the computer, or the keyboard itself.
- Roughly 50% of all keyboard keys produce letters, numbers or signs (characters). Other keys can produce actions when pressed, and other actions are available by simultaneously pressing more than one action key.
