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
Top Related