The current and future design of computers. Components. (hardware). Computer input

Data input devices have been used since the sixties as a graphic user interface (GUI) to allow a user to input certain information into computer systems and to modify or operate on images or information displayed on an output screen attached to the computer system.

Input examples are keyboard; CD ROMs; DVD ROMs; microphone (including speech analysis/recognition); graphic cards; digital video cards; scanners; cameras; camcorders; video devices such as TV and VCRs; sensors.

There has been trend toward the increased uses input technologies that provide a more natural user interface for computer users. You can now enter data and commands directly and easily into a computer system through pointing devices like electronic mice and touch pads, and technologies like optical scanning handwriting recognition, and voice recognition. These developments have made it unnecessary to always record data on paper source documents and then keyboard the data into a computer in an additional data entry step. Further improvement in voice recognition and other technologies should enable an even more natural user interface in the future.

Keyboards are still the most widely used devices for entering data and text into computer system, but they have some serious limitations. For example, persons who are not trained typists find using a keyboard tedious and error producing. That is why researches in such areas as pointing devices, optical character recognition, and speech recognition are seeking ways to eliminate or minimize the use of keyboards.

A computer keyboard has keys for all the characters as well as mathematical and foreign-language symbols. The enter key causes the cursor on the display to move to the beginning of a new line. The escape key, which is usually marked Esc, is often used to cancel data entries and to terminate the execution of commands and programs. The number keys along the top row of the keyboard are inconvenient for entering large amounts of numeric data. For that reason a numeric keypad, in which the number keys are arranged in a square array, as on a calculator is provided.

Holding down the shift key causes the letter keys to type uppercase rather than lowercase letters.

Holding down the control key (Ctrl) causes certain other keys, mainly letter keys, to generate control keys.

The Alt key, when pressed, establishes an alternate meaning for each key.

The Ctrl and Alt keys are often used to indicate that a keystroke represents a command to the program rather than a part of the input data.

Cursor control keys move the cursor on the display up, down, left, and right, allowing the user to position the cursor at the point on the display where data is to be entered or changes are to be made.

Pointing devices are a better alternative for issuing commands, making choices, and responding to prompts displayed on your video screen. They work with your operating system's graphical user interface (GUI), which presents you with icons, menus, windows, buttons, bars, and so on, for your selection. For example, pointing devices such as electronic mice and touch pads allow you to easily choose from menu selections and icon displays using point-and-click or point-and-drag methods.

The electronic mouse is the most popular pointing device used to move the cursor on the screen, as well as to issue commands and make icon and menu selections. By moving the mouse on a desktop or pad, you can move the cursor into an icon displayed on the screen. Pressing buttons on the mouse activates various activities represented by the icon selected.

The trackball, pointing stick, and touch pad are other pointing devices most often used in place of the mouse. A trackball is a stationary device related to the mouse. You turn a roller ball with only its top exposed outside its case to move the cursor on the screen. A pointing stick (also called a trackpoint) is a small buttonlike device, and sometimes likened to the eraserhead of a pencil. It is usually centered one row above the space bar of a keyboard. The cursor moves in the direction of the pressure you place on the stick. The touch pad is a small rectangular touch-sensitive surface usually placed bellow the keyboard. The cursor moves in the direction your finger moves on the pad. Trackballs, pointing sticks, and touch pads are

easier to use than a mouse for portable computer users and are thus built into most notebook computer keyboards.

Touch screens are devices that allow you to use a computer by touching the surface of its video display screen. Some touch screens emit a grid of infrared beams, sound waves, or a slight electric current that is broken when the screen is touched. The computer senses the point in the grid where the break occurs and responds with an appropriate action. For example, you can indicate your selection on a menu display by just touching the screen next to that menu item.

Comments:

pointing device координатно-вказівний пристрій, позицію вальний пристрій, вказівний пристрій, маніпулятор prompt запрошення, підказка (на екрані)

point-and-click " вказати і клацнути" - загальний метод роботи

з мишею в ОС

point-and-drag " вказати і перетягнути" - технологія роботи з ек­

ранними об'єктами у Windows за допомогою миші

to emit випромінювати

to occur траплятися, відбуватися

tedious нудний, стомливий

seek пошук; шукати, розшукувати, намагатись знайти