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
Dvorak Simplified Keyboard change. The Dvorak layout is often used in economics textbooks as a standard example of network effects, though this method has been criticized. Most keyboards are based on QWERTY patterns, despite the availability of other keyboard patterns, including the Dvorak. Although DSK is implemented in many languages other than English, there are still potential issues. Every Dvorak implementation for other languages has the same difficulties as for Roman characters. However, other (occidental) language orthographies can have other typing needs for optimization (many are very different from English). Because Dvorak Simplified Keyboard was optimized for the statistical distribution of letters of