Caps lock is a lock key found on many computer keyboards, depending on the local keyboard layout they implement.
Typical Caps lock behaviour is that pressing the key sets an input mode in which all typed letters are uppercase by default (i.e. in All caps). The keyboard remains in caps lock mode until the key is pressed again.
Keyboards often include a small LED to indicate that Caps lock is active, either on the key itself or in a row with Scroll lock and Num lock indicators. While on the original IBM PC keyboard this LED was controlled by the keyboard itself, it is under software control of the computer since the introduction of the IBM AT. Some new laptop and wireless desktop keyboards lack the LED, instead providing software that gives an on-screen indicator.
The Caps lock key is a modified version of the Shift lock key that occupies the same position on the keyboards of mechanical typewriters.
