Control-C else, typically returning control to the user. Ctrl-C was one of a handful of keyboard sequences chosen by the program designers at Xerox PARC to control text editing, with Ctrl-Z (Undo), Ctrl-X (Cut), Ctrl-V (Paste), and Ctrl-P (Print). The first four letters are all located together at the left end of the bottom row of the standard QWERTY keyboard, and P towards the upper right. The equivalent key combination on Macintosh computers is Command-C. Control-C as an abort command was popularized by TOPS-20 and TOPS-10 and adopted by other systems including Unix. It was also adopted by Digital Equipment operating
ISO/IEC 9995 of the keytops; the standard defines their position independent of the characters of the primary layout. Thus, e. g. the Yen symbol “¥” occupies the shifted position on the 6th letter key of the second row, whether this is the Y key on a QWERTY keyboard (like the US layout) or the Z key on a QWERTZ keyboard (like the German layout). The diacritical marks contained in the common secondary group act as dead keys, i.e. they are to be entered before the base characters they apply to. This mechanism is also to be used for sequences of more than