KEYBOARD

One of the main input devices used on a computer, a PC's keyboard looks very similar to the keyboards of electric typewriters, with some additional keys. Below is a graphic of the Saitek Gamers' keyboard with indicators pointing to each of the major portions of the keyboard.
Keyboard Types
QWERTY Keyboard
A standard computer keyboard is called a QWERTY keyboard because of the layout of its typing area. This keyboard is named after the first six leftmost letters on the top alphabetic line of the keyboard. A QWERTY keyboard might limit your typing speed. The QWERTY keyboard, which was named after the first six letters of its layout, is the standard design for both typewriters and computer keyboards. The QWERTY was originally designed to decrease the pace of text entry and to prevent key jamming in early mechanical typewriters. Modern computers to not suffer from key jamming, and many feel that it is time to consider alternative keyboard layouts.
Because the fluency of text entry is determined by the speed and accuracy of the user, it is important to examine these measures for alternative keyboard options. One option presently available is the Chubon keyboard, which was designed to improve the speed and efficiency of single digit entry (Chubon & Hester, 1988). Consequently, a comparison of the QWERTY keyboard and the Chubon keyboard can provide valuable information for occupational therapists who prescribe alternative keyboards for persons with disabilities, including those with low endurance and decreased strength.
Dvorak Keyboard
A keyboard with an alternative layout was designed to improve typing speed. Called the Dvorak keyboard, this type of keyboard places the most frequently typed letters in the middle of the typing area.

Here's a brief history of this alternative to QWERTY. In the 1930s, two efficiency experts named August Dvorak and William Dealey conducted a study of workplace efficiency in the office. One of their first discoveries was the strange QWERTY keyboard layout, which seemed to have been designed with at best no consideration for efficient typing. They began work on an alternative keyboard layout, and after many years published a new design called the American Simplified Keyboard or ASK. This design eventually became called the Dvorak Simplified Keyboard or DSK, named after Dr. Dvorak, who spent much of his life working on it, and then trying to promote it. (No, it's not named after PC industry pundit John C. Dvorak, but I read somewhere that they might be related. Perhaps if Mr. Dvorak reads this he could let me know. :^) )

The goals behind the Dvorak design are relatively common sense ones: move the most commonly-used letters to the home row where they are easy to reach, and exile infrequently-used keys to the outer reaches of the layout. Dvorak refined the design over many years until he came up with a design that he felt was ideal.

Now the interesting thing is that quite a lot of controversy swirls around the Dvorak design. Proponents of this layout consider it vastly superior to the QWERTY arrangement, and many have spent years in frustration attempting to overcome the inertia of the QWERTY design--including Dvorak himself, who lived a rather quixotic life trying to sell his improved design to an industry that just wasn't interested. At the same time there are skeptics that say the advantages of the Dvorak keyboard have been overstated. Some even claim the studies showing the superiority of the Dvorak design were conducted incompetently, or even dishonestly! I don't really know the truth behind all the claims and counter-claims, so I am not going to touch this controversy with a ten-foot pole. But I did want to mention that Dvorak is not universally acknowledged to be superior to QWERTY.

Those who like the Dvorak design make many claims regarding its superiority, and from a common-sense standpoint, they do make sense. The Dvorak design is supposed to allow faster typing with more accuracy, since 70% of keypresses are on the home row of the keyboard, compared to 31% with QWERTY. The layout is organized with the vowels on one side of the keyboard so that more alternation between right and left hand is used in typing common words. The reduced motion of the fingers is claimed to allow for greater comfort on the part of the typist, and some go so far as to say that using a Dvorak design will alleviate the symptoms of repetitive stress injuries associated with keyboards. I would have to see some valid medical evidence to be convinced of that, but again, it makes some intuitive sense to me.