The most widely used computer keyboard layout today comes from yesterday's typewriters. Christopher Latham Sholes invented the QWERTY keyboard for the commercial typewriter in 1874. "QWERTY" stands for the first six letters in the top row of letters. The QWERTY layout was designed to prevent a typewriter from jamming.
Another keyboard layout was created to improve typing efficiency in 1936 by August Dvorak and William Dealey. A Dvorak keyboard puts the high-frequency letters in the home row: AOEUIDHTNS, so that the cumulative distance traveled by the ten fingers is minimized.
This Demonstrations shows the letter frequency of some sample texts on QWERTY and Dvorak keyboards.