Substitute character actions than the last one can also be undone by pressing multiple times. was one of a handful of keyboard sequences chosen by the program designers at Xerox PARC to control text editing. Presumably these particular keystrokes were chosen because of their location on a standard QWERTY keyboard, since the Z (undo), X (cut), C (copy), and V (paste) keys are located together at the left end of the bottom row of the standard QWERTY keyboard. Substitute character A substitute character (␚) is a control character that is used in the place of a character that is recognized to be
Keyboard layout a cause of the divergence between the bit-paired keyboards found in the 1960s and 1970s and the typewriter-paired keyboards that are now standard in the US. This change was made because smaller characters hit the paper with less force, and consolidating smaller characters such as '" into a pair on a single key avoided needing to adjust the force based on shift state. The standard 101/102-key PC keyboard layout was invented by Mark Tiddens of Key Tronic Corporation in 1982. IBM adopted the layout on its PC AT in 1984 (after previously using an 84-key keyboard which did not have