Keyboard

Keyboard:

Keyboard is the most commonly used input device. Data is mostly entered using a keyboard. The buttons on the keyboard are called keys. A keyboard contains over 100 keys. The arrangement of keys on keyboard is called its layout. The most popular keyboard layouts are QWERTY and Dvorak.The keys on computer keyboards are often classified as follows: 

•  Numeric Keypad:

Numeric keypad is located on the right hand side of most keyboards. It has arithmetic operators keys 

 +, - ,* , / that  are used in arithmetic operations and digits from 0 to 9 . It also has a key Num Lock. When this key is off, the keypad cannot be used to type numbers. 

• Function Keys:

Function keys from F1 to F12 perform special functions. Their function depends on the software being used in the computer.

• Alphanumeric keys  

Alphanumeric keys include all letter keys in alphabet (A to Z) and digits from 0 to 9. 

• Backspace Key:

Backspace key is used to delete single character on the left of the cursor on the screen. 

• Enter Key:

Enter key is used to enter command or input data in the computer. 

• Caps Lock Key:

Caps Lock is a toggle key. The characters appear in uppercase if it is pressed. The characters appear in lowercase if it is not pressed. Numbers and symbols are not affected. The status light under''Caps Lock'' turns on when it is pressed.

• Tab Key:

Tab Key is used to move the cursor to the next tab stop. It is also used in dialog boxes to move from one option or field to another. 

• Modifier Keys:

These are used to modify the input of other keys. A specific key is pressed while holding down one of these keys to achieve required result. These keys are as follows:

1.Control Keys :

CTRL keys produce different results depending on type of software.Sometimes this key is used with other keys as shortcut to some commands. For example CTRL+O is used to open a new file.

2.Alt Keys:

alt keys are always used in combination with other keys to perform special functions. In windows- based programs, these keys are used to navigate menus and dialog boxes without using a mouse.

3.Shift Keys:

It is used to output capital letter or special symbol.In most word processors, it is used with various cursor movement keys to select text for editing.

• Cursor-Movement Keys:

 These keys are used to move around the screen and are as follows:

1.Home: 
Home key is normally used in word processing or text editors to move cursor to the top of screen.

2.End: 
End  key is normally used in word processing to move the cursor to the right of screen or to the end of screen or document.
3.Arrows:
The keys that move the cursor are called Arrow Keys or Cursor Control Keys. These keys have an up arrow , a down arrow , a left arrow, and right arrow. 
4.Page Up:
Pg Up key is normally used in word processing or other applications to move the cursor one page up on screen.
5.PageDown:

PgDn key is normally used in word processing or other applications to move the cursor one page down on screen.

Special-Purpose Keys:

These keys are used for special purposes and are as follows:
Esc:  
ESC key is used to terminate command or current task.
Delete: 
It is used to delete the character to the right side of the cursor. It is also used to delete the selected object.
Insert:
It is a toggle key used to switch between Insert Mode and Overtype Mode. 
Print Screen: 
It is used to capture everything that appears on the screen.
Scroll Lock:It locks and unlocks the cursor on screen in some programs. The cursor moves normally when it is turned off. It does not work in all programs.
Pause / Break:It is used to pause screen when information is too fast to read.