Keyboard

The keyboard was one of the first peripherals to be used with computers, and it is still the primary input device for entering text and numbers. A standard keyboard includes about 100 keys; each key sends a different signal to the CPU. Most of the keyboards have following keys.

1.1.       The Alphanumeric Keys

The alphanumeric keys—the area of the keyboard that looks like a typewriter’s keys—is arranged the same way on almost every keyboard. Sometimes this common arrangement is called the QWERTY (pronounced KWER-tee) layout because the first six keys on the top row of letters are Q, W, E, R, T, and Y. Along with the keys that produce letters and numbers, the alphanumeric key group includes four keys having specific functions. The TAB, CAPS LOCK, BACKSPACE and ENTER keys.

1.2.       The Modifier Keys

The SHIFT, ALT (Alternate), and CTRL (Control) keys are called modifier keys because they modify the input of other keys. In other words, if you hold down a modifier key while pressing another key, then you are changing the second key's input in some way. For example, if you press the j key, you input a small ‘j’ letter But if you hold down the shift key while pressing the’ J’ key, you input a capital ‘ J’.

1.3.       The Numeric Keypad

The numeric keypad is usually located on the right side of the keyboard. The numeric keypad looks like a calculator's keypad, with its 10digits and mathematical operators (+, -, *, and /). The numeric keypad also features a NUMLOCK key, which forces the numeric keys to input numbers. When NUM LOCK is deactivated, the numeric keypad's keys perform cursor movement control and other functions.

1.4.       The Function Keys

The function keys (which are labeled F1, F2 and so on) are usually arranged in a row along the top of the keyboard. They allow you to input commands without typing long strings of characters or navigating menus or dialog boxes. Each function key's purpose depends on the program you are using. For example, in most programs, F1 is the help key. When you press it, a special window appears to display information about the program you are using.

1.5.       The Cursor-Movement Keys or Control Keys

Most standard keyboards also include a set of cursor-movement keys, which let you move around the screen without using a mouse. In many programs and operating systems, a mark on the screen indicates where the characters you type will be entered.

The control keys allow the user to make large jumps in most applications. Common control keys include:

• Home
• End
• Insert
• Delete
• Page Up
• Page Down
• Escape (Esc)