Since its inception, the IBM PC keyboard had a CAPS LOCK. In the first version for PC/XT, CAPS LOCKS was located to the bottom right of the letter keys area. However, subsequent models switched the places of the CAPS LOCK key and the Control key. As such, CAPS LOCK has since been placed on left edge of the keyboard, above the Shift key and below the Tab key, next to letter A. This layout has become the "de facto" popular standard.