COMPUTERS: TOOLS FOR AN INFORMATION AGE Chapter 5 – Part 2 Input and Output.

COMPUTERS:TOOLS FOR AN INFORMATION AGE

Chapter 5 – Part 2Input and Output

Output: Information for the User

Computer screensPrintersVoice outputMusic outputMicroform

Computer Screen Technology

Screen is part of computer’s monitor Screen output known as soft copy temporary

Common forms Cathode ray tube (CRT) Flat-panel screens

CRT Screens

Display text and graphics

Most are in color

Graphics card converts signals from the control unit into the image the user sees

Factors Affecting Performance

Scan rate The frequency with which the image is refreshed

Resolution (clarity) of screen Measured in pixels (picture elements) The more pixels, the higher the resolution

Dot pitch The amount of space between dots The smaller the dot pitch, the sharper the image

Video memory A high-speed form of RAM installed on graphics card

Graphic Standards

Agree on resolutions, colors, other issues related to displaying graphics

Super Video Graphics Adapter (SVGA) is most common standard Provides 800 (horizontal) x 600 (vertical) pixels on the

display

Support 16 million colors The number of colors that can be displayed depends on

amount of video memory

Flat-Panel Screens

Liquid crystal display (LCD)Very thin (only a few inches)Produce sharper text images than CRTsEasier on eyes than CRTsFlat-panel technologies

LCD Technologies

Active-matrix Uses many thin-film transistors (TFT) Produces brighter image and can be viewed from

wider angles

Passive-matrix Uses fewer transistors Cheaper and uses less power

Gas plasma Supports very large displays Has brilliant color display Viewable at very wide angles

Printers

Produce information on paper output Printed output known as hard copy

Orientation settings Portrait - vertical alignment Landscape - horizontal alignment

Two ways of printing Impact printer Nonimpact printer

Impact Printers

Physical contact with paper required to produce image

Dot-matrix printer Has print head consisting of one or more columns of pins Pins form characters and images as pattern of dots

Nonimpact Printers

Places an image on a page without physically touching it

Laser printer Uses light beam to help transfer images to paper Produces high-quality output at very fast speeds

Ink-jet printer Sprays dots of ink Less expensive than laser printers

Voice Output

Converts data to vocalized soundsUsed in automated telephone-based customer

service applications

Music Output

Multimedia clips, games, videos include sight and sound Speakers placed on side of monitor

Computer Output Microform (COM)

Output of photographically reduced images on microfilm

Common use Libraries store back issues of magazines, newspapers, etc.

Terminals

Combine input and output capabilities

Dumb terminal Keyboard for input and monitor for output No processing capability

Intelligent terminal Has limited memory and a processor

Computer Graphics

Business graphicsVideo graphicsComputer-aided design (CAD)

Business Graphics

A powerful way to display information Colorful graphics, maps, and charts help

managers compare data, and make quicker decisions

As underlying data changes, charts and graphs are instantly updated

Terminals

Combine input and output capabilities

Dumb terminal Keyboard for input and monitor for output No processing capability

Intelligent terminal Has limited memory and a processor

Video Graphics

A series of video images Displayed rapidly to give the impression of motion

Used extensively in television

Also used in computer and arcade video games

Computer-Aided Design (CAD)

Creates two- and three-dimensional (2D and 3D designs)

Serves as bridge between design and manufacturing