Computer Sciences

Keyboard Devices:

Most input data is entered input the computer by using a keyboard. This input methods is similar to typing on a typewriters.

Most typewriters and computer keyboards are Qwerty Keyboards. The alphabetic keys are arranged so that the upper-left row of letters begins with the six letters QWERTY. Designers of other keyboards claim that their boards are easier to learn than the QWERTY keyboard.

Computer keyboards

Include keys that are designed to perform specific tasks. These special keys include function keys, directional keys and special-purpose keys such as Alt, Ctrl, Enter, Ins, and Esc. These keys enable the user to perform complex tasks easily when using the application.

Some of keyboards have even 112 keys, with three new keys designed to simplify working with Windows 98. two of these keys, next to the Alt key, bring up Start menu. The third key, next to the right Ctrl key, brings up a menu of functions that are frequently accessed in whichever application is currently being used.


Point and Draw Devices : Many people use devices instead of keyboards whenever possible. Pointing devices minimize the amount of typing (consequently, the number of errors). The many pointing devices available include the mouse, trackball, light pen, digitizing tablet, touch screen and pen-based systems.




The Mouse and Track Ball: The mouse is a palm-size device with a ball built into the button. The mouse is usually connected to the computer by the cable (computer wires are frequently called cables) and many have from one to four buttons (usually two). The mouse may be mechanical or optical and comes in many shapes and sizes. When you move the mouse over a smooth surface, the calls rolls, and the pointer on the display screen moves in the same direction. The Apple Macintosh, with its graphical user interface, made the mouse popular. Now, most microcomputer systems, regardless of the manufacturer, use a mouse. With the mouse, you can draw, select options from a menu and modify or move text. You issue commands by pointing with the pointer and clicking a operating a microcomputer easier for beginning users.



Touchpad:

The touch pad is a stationary pointing devices that people find less tiring to use than a mouse or a track ball. The movement of a finger across a small touch surface is translated into cursor movement on the computer screen. The touch sensitivity surface may be just 1.5- 2 inch square, so the finger does not have to move much. Its size makes it most suitable for the notebooks or the laptops.

A device

That was released in 1995 enables the user to move the cursor using and infrared pen. The pen is cordless and works when it is as fifteen feet from the screen. Although the mouse is still the most pointing device, these innovations may change that in future.



Joysticks:
A joysticks is a pointing device often used for playing games. The joystick has a gearshift-like lever that is used to move the pointer on the screed. On most joysticks, a button on the top is used to select options. In industry and manufacturing, joysticks are used to control robots. Flight simulators and other training simulators also use joysticks.


Touch-Sensitive Screens:

Perhaps the easiest way to enter data is with the touch of finger. Touch screens enable the user to select and option by pressing a specific part of the screen. Touch screens are commonly used in grocery stores, fast-food restaurants and information kiosks.