Keyboards are one of the most important input devices for a computer. They serve as your primary means of communication with your computer! I am sure that you all have used a keyboard sometime in your life. Anyway, keyboards are a type of keypad similar to a typewriter with a set of buttons that you press to input data into your computer.
Most keyboards have an ASCII (American Standard Code for Information Interchange) layout. This layout includes a numeric keypad, special function keys, special control keys, as well as typing keys.
Typing Keys:
The typing keys are just the keys containing the twenty-six letters of the alphabet. These keys have a QWERTY setup. QWERTY stands for the first six letters in the top row of the standard letter keys, and was first designed by American Christopher Sholes in 1890. It was designed so that the most commonly used letters would not be near each other. This is to prevent people to type too fast, because fast typing often results in the keyboard jamming. Of course, jamming is no longer a problem today, but as most people are already accustomed to the QWERTY keyboard, there is no necessity to change it.
Numeric Keypad:
The numeric keypad is the group of 17 keys on the very right of your keyboard. It includes all of the numbers from 0-9, a plus sign, a minus sign, and a few other various keys. If you look closely, you'll realize that the arrangement of the keys on a numeric keypad on your keyboard is quite similar to the arrangement of the keys on a calculator! Because many computers are used for business purposes and to input numbers into a computer, the numeric keypad was designed. This made it easier and faster to input numbers.
Function Keys:
The function keys can be found in a row at the very top of your keyboard. They are labeled "F1," "F2," "F3," all the way up to "F12." These function keys are mainly used to simplify the use of applications. They perform special commands, depending on which application is open. For example, pressing F7 in a word document opens the spell check. In almost all applications, pressing F1 opens a help menu. Also, the function keys can be combined with other keys, like the control keys to perform different tasks!
Control Keys:
The control keys are special keys like del (delete), ctrl (control), alt (alternate), shift, and enter. The delete (or backspace) key is used to erase characters in a word document. The esc (escape) key is generally used to exit out of a program or application, while when you strike the enter key, a function or command is carried out. The tab key is primarily used to indent in a word document. The shift key is often used in conjunction with other keys. For example, pressing shift and a letter will make that letter capital, while pressing shift and a number will display the character shown right above that number. Finally, there are the ctrl and alt keys. Like the shift key, these are also used in conjunction with other keys, and they usually perform functions similar to those of the function keys. There are also the cursor movement keys. These are the arrows shaped like an inverted T located between the typing keys and the numeric keypad. These keys are used to move the cursor around on your screen. For example, if you were in a word document, the blinking cursor will move up and down to different lines if you press the up and down cursor movement keys.
What happens when you press a key on the keyboard:
2. The keyboard sends an electrical signal to the central processing unit (CPU) telling it that a key was pressed
3. The CPU is almost ALWAYS busy. Thus the letter "a" is temporarily stored in a special memory cell until the CPU is ready to work with it.
4. The keyboard controller tells the central processing unit that there is information waiting to be processed.
5. The CPU figures out which application you were in when you pressed the key. For example, you might have an Internet browser and a word document open at the same time. The processor will determine whether you pressed the "a" in the word document or in the Internet browser.
6. Assuming that you pressed the key in a word document browser, the letter will be added to the computers random-access memory (it takes up one byte of space).
7. Then, the letter "a"
will be displayed on the computer screen.
1995-2001, ThinkQuest Inc.all rights reserved
