The Standard Keyboard Layout

Keyboards for personal computers come in many styles. the various models differ in size, shape and feel, but except for a few special - purpose keys , most keyboards are laid out almost identically. Among IBM - compatible computers, the most common keyboard layout is the IBM Enhanced keyboard. It has 101 keys arranged in five groups as shown in the figure.The keyboard layout is close to the IBM Enhanced keyboard, but there are a few differences.

The Alphanumeric keys:
The alphanumeric keys - the parts of the keyboard that look like a typewriter - arrange the same way on almost every keyboard, Some times this common arrangement is called QWERTY layout because the first six keys on the top row of letters are Q,W,E,R,T and Y.
For decades, many expert typists have supported a different arrangement for alphanumeric keys called the DVORAK keyboard. This keyboard layout places the most commonly used letters in the middle row of keys, making them easier to reach. Special DVORAK keyboards are available for computer system but they are not standard equipment. A few keyboards manufacturers now offer keyboards that can be switched from QWERTY to DVORAK configurations.

Along with the keys that produce letters and numbers , the alphanumeric key group includes a few additional keys, with specific functions. these keys are similar to those found on a typewriter:

* Tab - The Tab key moves you to predefined tab stops in many application programs. In dialog boxes.you can press tab to move from one option or field to another.

* caps Lock  - As the name implies this key lets you "lock" the alphabet keys so they produce only capital letters. Caps lock does not affect the numeric keys or the keys that produce punctuation or special characters.

* Back Space - This key enables you to erase characters you have just typed for example in a word processing program you can press Backspace to "back over" an incorrect  character and delete it.

* Enter - The Enter key lets you finalize data entry in many types of the application programs . you can also use enter to choose commands and options in many programs and at various places in an operating systems interface.

The Modifier keys:


A keyboard's modifier keys are no named because they are used to modify the input of other keys. You press
another key while holding down one of the modifier keys are as follows:

* shift - A computers shift keys have the same function as a typewriters shift  keys; when pressed in conjunction with an alphanumeric key , shift forces the computer to output a capital letter or symbol. Shift also acts as a modifier key on some programs. In most word processors you can press shift along with various cursor movement keys to select text for editing.

* Ctrl - This key produces different results depending on the program you are using. In many windows based
programs, ctrl - key  combinations provide shortcuts for menu commands. For example , the crtl key combination  ctrl +o enables you to open a new file.

* Alt - this key called the alternative key operates like that control key.except that it produces different set of results. In windows based programs, Alt -key combination enable you to navigate menus and dialog boxes without using a mouse.