Standard Keyboards - there are many types of keyboards, with three standard types - the original XT keyboard from 1970's with 84 keys; the AT keyboard, also with 84 keys; and the enhanced keyboard, with 101 keys.  Even though they have the same number of keys - a motherboard designed for an AT keyboard will not accept an XT keyboard - they are not compatible !!

The keys enable you to enter data into a computer. Computer keyboards are similar to electric-typewriter keyboards but contain additional keys. The keys on computer keyboards are often classified as
follows: 

• alphanumeric keys -- letters and numbers
• punctuation keys -- comma, period, semicolon, and so on. 
• special keys -- function keys, control keys, arrow keys, Caps Lock key, and so on.  
  

Ergonomic Keyboards - There are also the "ergonomic" keyboards, which are separated into two areas, and are curved so as to fit the hand and forearm positions more naturally.  If you are a "hunt and peck" typist like me - stay clear of these !!

Dvorak Keyboards - regular keyboards are often referred to as "QWERTY" keyboards, since the first 6 letters from left to right spell out "QWERTY".  Yet another type of keyboard is designed for speed typing - the "Dvorak" keyboard.  The Dvorak is not named after the top row of keys - instead it was designed in the 1930s by August Dvorak, a professor of education, and his brother-in-law, William Dealy. Unlike the traditional QWERTY keyboard, the Dvorak keyboard is designed so that the middle row of keys includes the most common letters. In addition, common letter combinations are positioned in such a way that they can be typed quickly.

It has been estimated that in an average eight-hour day, a typist's hands travel 16 miles on a QWERTY keyboard,
but only 1 mile on a Dvorak keyboard.  In addition to the standard Dvorak keyboard, there are two additional Dvorak keyboards, a left-handed and right-handed keyboard. These keyboards are designed for people who have only one hand for typing.