what is keyboard in computer

The most common of all input devices is the keyboard. Several versions of keyboards are available. The best and most expensive of these is the full-stroke keyboard. This is ideal for word processing and other volume data and program entry activities. This type of keyboard is available with most mainframe computer terminals or the expensive microcomputer systems.

Some popular microcomputers offer enhanced keyboard for easy entry of numbers. This is accomplished with a smaller group of keys known as a numeric keypad at the right of the keyboard. These keys generally consist of the digits, a decimal point, a negative sign, and an ENTER key. This type of keyboard is ideal for accounting operations, which require a large volume of numbers to be entered.

Keyboards generally utilize integrated circuits to perform essential functions, such as determining the combination of 1s and 0s, or binary code, to send to the CPU, corresponding to each key depressed, switching between shifted and nonshifted keys, repeating a key code if a key is held down for a prolonged period of time, and temporarily storing or "buffering" input when keys are typed too fast.

The keyboard arrangement provided as standard on most keyboards is the QWERTY arrangement, named for the six letters beginning the row at the top left of the keyboard (Figure 4.1). This arrangement was chosen intentionally to slow expert typists, since those who typed too fast would cause the keys on a mechanical typewriter to jam. Slowing down the typist was accomplished by scattering the most used around the keyboard, making frequently used combinations of letters awkward and slower to type. This QWERTY keyboard arrangement has been used for nearly a century.

The Dvorak Simplified Keyboard (DSK) arrangement, designed in 1932 by August Dvorak, is the result of extensive ergonomic studies. Dvorak noted that with the QWERTY keyboard arrangement, typists used the weakest fourth and fifth fingers of their left hand a large proportion of the time. Thus, Dvorak rearranged the keyboard so that the five more frequently used vowels (a, o, e, u, and i) and the five most frequently used consonants (d, h, t, n, and s) were positioned on the home row where the fingers of the left and right hands rest, respectively (Figure 4.2). Thus, 70 percent of the typing is done on the home row. He then placed the next most frequently used characters in the row above the home row and the least frequently used characters in the row below the home row. This resulted in a reduction of finger movement of approximately 80 percent and overall, an increase in productivity of nearly 40 percent.

Expert typists and word processors generally agree that using the Dvorak arrangement increases productivity while simultaneously decreasing fatigue. The world's fastest typing speed, nearly 200 words per minute, was achieved on a Dvorak keyboard. Despite these improvements the QWERTY keyboard arrangements is still the most common because of the difficulty of overcoming inertia and retraining.

In the mean while, microcomputer manufacturers and software vendors are producing software that will convert your keyboard from QWERTY to Dvorak, and back again at will. To date, larger computer systems employ the traditional QWERTY arrangement only.

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