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
QWERTY of letters, but the contribution was later called into question. Others suggest instead that the letter groupings evolved from telegraph operators' feedback. In November 1868 he changed the arrangement of the latter half of the alphabet, O to Z, right-to-left. In April 1870 he arrived at a four-row, upper case keyboard approaching the modern QWERTY standard, moving six vowel letters, A, E, I, O, U, and Y, to the upper row as follows: In 1873 Sholes's backer, James Densmore, successfully sold the manufacturing rights for the Sholes & Glidden Type-Writer to E. Remington and Sons. The keyboard layout was finalized