The QWERTY keyboard layout was devised and created in the early 1870s by Christopher Sholes. ... Sholes struggled for the next six years to perfect his invention, making many trial-and-error rearrangements of the original machine's alphabetical key arrangement in an effort to reduce the frequency of typebar clashes. Eventually he arrived at a four-row, upper case keyboard approaching the modern QWERTY standard.
...enabling salesmen to impress customers by pecking out the brand name "TYPE WRITER" from one keyboard row.
In the QWERTY layout many more words can be spelled using only the left hand than the right hand. In fact, thousands of English words can be spelled using only the left hand, while only a couple of hundred words can be typed using only the right hand. This is helpful for left-handed people.
Sholes typewriter, 1873
from http://en.wikipedia.org/wiki/Qwerty
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2. The Dvorak layout [patented 1936] was designed to address the problems of inefficiency and fatigue which characterized the QWERTY keyboard layout. The QWERTY layout was introduced in the 1860s [or 70s?], being used on the first commercially-successful typewriter, the machine invented by Christopher Sholes. The QWERTY layout was designed so that successive keystrokes would alternate between sides of the keyboard so as to avoid jams.
Dvorak studied letter frequencies and the physiology of people's hands and created a layout to adhere to these principles:
Dvorak Simplified Keyboard
* Letters should be typed by alternating between hands.
* For maximum speed and efficiency, the most common letters and digraphs should be the easiest to type. This means that they should be on the home row, which is where the fingers rest, and under the strongest fingers.
* The least common letters should be on the bottom row, which is the hardest row to reach.
* The right hand should do more of the typing, because most people are right-handed.
* Digraphs should not be typed with adjacent fingers.
* Stroking should generally move from the edges of the board to the middle. An observation of this principle is that, for many people, when tapping fingers on a table, it is easier going from little finger to index than vice versa. This motion on a keyboard is called inboard stroke flow.
The Dvorak layout was intended for the English language. In other European languages, letter frequencies, letter sequences, and digraphs differ from English. Also, many languages have letters that do not occur in English. For non-English use, these differences lessen the supposed advantages of the original Dvorak keyboard. However, the Dvorak principles have been applied to the design of keyboards for these other languages.
(Several alternatives to QWERTY have been developed over the years, claimed by their designers and users to be more efficient, intuitive and ergonomic. Nevertheless, none has seen widespread adoption, due partly to the sheer dominance of available keyboards and training. Studies are inconclusive as to whether they actually offer any real benefits.)
from http://en.wikipedia.org/wiki/Dvorak_Simplified_Keyboard and http://en.wikipedia.org/wiki/Qwerty
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