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
Keyboard layout rest, thus having 70% of typing done in the home row (compared to 32% in QWERTY). The Dvorak Simplified Keyboard is available out-of-the-box on most operating systems, making switching through software very easy. "Hardwired" Dvorak keyboards are also available, though only from specialized hardware companies. The Colemak layout is another popular alternative to the standard QWERTY layout, offering a more familiar change for users already accustomed to the standard layout. It builds upon the QWERTY layout as a base, changing the positions of 17 keys while retaining the QWERTY positions of most non-alphabetic characters and many popular keyboard shortcuts, supposedly