Copyright © 2003 by Prentice Hall Computers: Tools for an Information Age Chapter 5 Input and Output: The User Connection

2Copyright © 2003 by Prentice Hall Objectives Describe the user relationship with computer input and output Explain how data is input into a computer system and differentiate among various input equipment Describe how a monitor works and the characteristics that determine quality List and describe the different methods of computer output

3Copyright © 2003 by Prentice Hall Objectives Differentiate among different kinds of printers Explain the function of a computer terminal and describe the types of terminals Describe the ethical considerations involved in handling computer data

4Copyright © 2003 by Prentice Hall How Users See Input and Output Users submit data (input) to the computer to get processed information (output) Output can be instant reaction to input Output can be instant reaction to inputinstant reaction instant reaction Also can be separated by time, distance, or both Also can be separated by time, distance, or bothseparated by timeseparated by time

5Copyright © 2003 by Prentice Hall Instant Reaction Items scanned at supermarket Produce item name and price at counter Produce item name and price at counter Forklift operator speaks to computer Forklift obeys operator’s commands Forklift obeys operator’s commands Sales rep enters an order on a pad Characters displayed as “typed” text and stored in pad Characters displayed as “typed” text and stored in pad Factory workers punch a time clock as they go from task to task Produce weekly paychecks and management reports Produce weekly paychecks and management reports Return

6Copyright © 2003 by Prentice Hall Input and Output Separated Data on checks input into bank computer Computer processes entries once a month to prepare statements Computer processes entries once a month to prepare statements Charge-card transactions provide input Processed monthly to produce customer bills Processed monthly to produce customer bills Water samples collected and input into computer Used to produce reports that show patterns of water quality Used to produce reports that show patterns of water quality Return

7Copyright © 2003 by Prentice Hall Input: Getting Data from the User to the Computer Keyboard Pointing devices Pointing devices Source data automation Source data automation

8Copyright © 2003 by Prentice Hall Keyboard Similar to typewriter keyboard May be part of a personal computer May be part of a personal computer May be part of a terminal connected to a computer in another location May be part of a terminal connected to a computer in another location Can be unique to an industry Keys on McDonald’s keyboards represent Big Mac or large fries Keys on McDonald’s keyboards represent Big Mac or large fries Ergonomic keyboards Ergonomic keyboards Return

9Copyright © 2003 by Prentice Hall Ergonomic Keyboards Designed to reduce or minimize repetitive strain injury of wrists Provide more natural, comfortable position of wrists, arms, and hands Provide more natural, comfortable position of wrists, arms, and hands Return

10Copyright © 2003 by Prentice Hall Anatomy of a Keyboard

11Copyright © 2003 by Prentice Hall Pointing Devices Used to position a pointer on the screen Communicate commands to operating system by clicking a button Common devices Mouse Mouse Mouse Devices used for games Devices used for games Devices used for games Devices used for games Devices used in laptops Devices used in laptops Devices used in laptops Devices used in laptops Others Others Others Return

12Copyright © 2003 by Prentice Hall Mouse The most common pointing device Movement on flat surface causes movement of pointer on screen Movement on flat surface causes movement of pointer on screen Several types Mechanical - small ball on underside rolls as mouse is moved Mechanical - small ball on underside rolls as mouse is moved Optical - uses a light beam to monitor mouse movement Optical - uses a light beam to monitor mouse movement Cordless - uses either infrared or radio waves, rather than a cord, to connect to computer Cordless - uses either infrared or radio waves, rather than a cord, to connect to computer Return

13Copyright © 2003 by Prentice Hall Trackball and Joystick Trackball Variation on mechanical mouse Variation on mechanical mouse User rolls the ball directly User rolls the ball directly Often built into laptop computers Often built into laptop computersJoystick Short lever with handgrip Short lever with handgrip Distance and speed of movement controls pointer’s position Distance and speed of movement controls pointer’s position Pressing trigger causes actions to take place Pressing trigger causes actions to take place Return

14Copyright © 2003 by Prentice Hall Touchpad and Pointing Stick Touchpad Rectangular pressure-sensitive pad Rectangular pressure-sensitive pad Sliding finger across pad moves pointer Sliding finger across pad moves pointer Tapping with finger recognized as click Tapping with finger recognized as click Pointing stick Small pressure-sensitive post mounted in center of keyboard Small pressure-sensitive post mounted in center of keyboard Pushing post in any direction moves pointer Pushing post in any direction moves pointer Return

15Copyright © 2003 by Prentice Hall Other Pointing Devices Graphics tablet User moves stylus or puck across board User moves stylus or puck across board Used to create or trace precise drawings Used to create or trace precise drawings Touch screen Allow user to touch items on screen Allow user to touch items on screen Position of finger on screen determines item to be input into system Position of finger on screen determines item to be input into system Used at kiosks in public places such as malls Used at kiosks in public places such as malls Pen-based computing Use pen-like stylus to input data Use pen-like stylus to input data Often used in PDAs or pocket PCs Often used in PDAs or pocket PCs Return

16Copyright © 2003 by Prentice Hall Source Data Automation Use of special equipment to collect data at the source Primary areas Magnetic-ink character recognition (MICR) Magnetic-ink character recognition (MICR) Magnetic-ink character recognition Magnetic-ink character recognition Optical recognition devices Optical recognition devices Optical recognition devices Optical recognition devices Other sources Other sources Other sources Other sources Return

17Copyright © 2003 by Prentice Hall MICR Uses a machine to read characters made of magnetized particles Banking industry is predominant user Characters preprinted on lower left-hand side of check Characters preprinted on lower left-hand side of check Amount added by MICR inscriber when check is cashed Amount added by MICR inscriber when check is cashed Return

18Copyright © 2003 by Prentice Hall Optical Recognition Uses a light beam to scan data and convert to electrical signals Common uses Common uses ScannersScanners are the most common form Scanners Other optical recognition methods Other optical recognition methods Return

19Copyright © 2003 by Prentice Hall Common Uses Scanners at supermarkets Document imaging - converts paper documents to electronic versions Documents stored on disk Documents stored on disk Can be edited or processed by software Can be edited or processed by software

20Copyright © 2003 by Prentice Hall Scanners Flatbed scanner Typically scans one page at a time Typically scans one page at a time Can be used to scan large bound documents Can be used to scan large bound documents Sheetfed scanner Motorized rollers feed sheet across scanner head Motorized rollers feed sheet across scanner head Handheld scanner Smallest and least accurate Smallest and least accurate Optical character recognition (OCR) software required to convert picture into characters Return

21Copyright © 2003 by Prentice Hall Other Optical Recognition Methods Optical Mark Recognition Machine senses marks on piece of paper Machine senses marks on piece of paper Optical character recognition Wand reader reads characters in special typeface Wand reader reads characters in special typeface Bar Codes A series of vertical marks A series of vertical marks Represents a unique code Represents a unique code Universal Product Code (UPC) used as standard in supermarkets Return

22Copyright © 2003 by Prentice Hall Other Sources Voice input Voice input Digital cameras Digital cameras Video input Video input Return

23Copyright © 2003 by Prentice Hall Voice Input User speaks to computer Speech recognition devices convert spoken words into binary digits Speech recognition devices convert spoken words into binary digits Most are speaker-dependent System “learns” user’s voice System “learns” user’s voice Types of systems Discrete word systems - user must pause between words Discrete word systems - user must pause between words Continuous word systems - user can speak normally Continuous word systems - user can speak normally Return

24Copyright © 2003 by Prentice Hall Digital Camera User takes photo that is stored on a chip Photo can be downloaded to computer Use photo-editing software to enhance Use photo-editing software to enhance Store permanently on CDs or DVDs Store permanently on CDs or DVDs Photos composed of many pixels of color Photos stored on removable memory card Return

25Copyright © 2003 by Prentice Hall Video Input Digital video consists of series of still frames Displayed rapidly enough to give illusion of motion Displayed rapidly enough to give illusion of motion Web cam used to transmit video over the Internet Can capture video from analog sources with video capture card Return

26Copyright © 2003 by Prentice Hall Output: Information for the User Computer screens Computer screens Printers Voice output Voice output Music output Music output Microform

27Copyright © 2003 by Prentice Hall Computer Screen Technology Screen is part of computer’s monitor Screen output known as soft copy Screen output known as soft copy Intangible and temporary Intangible and temporary Common forms Cathode ray tube (CRT) Cathode ray tube (CRT) Cathode ray tube (CRT) Cathode ray tube (CRT) Flat-panel screens Flat-panel screens Flat-panel screens Flat-panel screens Smart displays Smart displays Smart displays Smart displays Return

28Copyright © 2003 by Prentice Hall CRT Screens Display text and graphics Most are in color Most are in color Some monochrome monitors are used in applications that have no need for color or graphics Some monochrome monitors are used in applications that have no need for color or graphics Graphics card converts signals from the control unit into the image the user sees Factors affecting performance Factors affecting performance Return

29Copyright © 2003 by Prentice Hall Factors Affecting Performance Scan rate The frequency with which the image is refreshed The frequency with which the image is refreshed Resolution (clarity) of screen Measured in pixels (picture elements) Measured in pixels (picture elements) The more pixels, the higher the resolution The more pixels, the higher the resolution Graphics standards exist Graphics standards exist Graphics standards exist Graphics standards exist Dot pitch The amount of space between dots The amount of space between dots The smaller the dot pitch, the sharper the image The smaller the dot pitch, the sharper the image Video memory A high-speed form of RAM installed on graphics card A high-speed form of RAM installed on graphics card Return

30Copyright © 2003 by Prentice Hall Graphic Standards Agree on resolutions, colors, other issues related to displaying graphics Super Video Graphics Adapter (SVGA) is most common standard Super Video Graphics Adapter (SVGA) is most common standard Provides 800 (horizontal) x 600 (vertical) pixels on the display Other varieties of SVGA exist Other varieties of SVGA exist Support 16 million colors Support 16 million colors The number of colors that can be displayed depends on amount of video memory Return

31Copyright © 2003 by Prentice Hall Flat-Panel Screens Liquid crystal display (LCD) Originally used for laptops, but making their way to desktop computers Originally used for laptops, but making their way to desktop computers Very thin (only a few inches) Produce sharper text images than CRTs Easier on eyes than CRTs Flat-panel technologies Flat-panel technologies Return

32Copyright © 2003 by Prentice Hall LCD Technologies Active-matrix Uses many thin-film transistors (TFT) Uses many thin-film transistors (TFT) Produces brighter image and can be viewed from wider angles Produces brighter image and can be viewed from wider anglesPassive-matrix Uses fewer transistors Uses fewer transistors Cheaper and uses less power Cheaper and uses less power Gas plasma Supports very large displays Supports very large displays Has brilliant color display Has brilliant color display Viewable at very wide angles Viewable at very wide angles Return

33Copyright © 2003 by Prentice Hall Smart Displays Based on flat-panel technology Each contains its own processor Wireless transmitter-receiver allows user to control desktop from anywhere in the house Return

34Copyright © 2003 by Prentice Hall Printers Produce information on paper output Printed output known as hard copy Printed output known as hard copy Orientation settings Portrait - vertical alignment Portrait - vertical alignment Landscape - horizontal alignment Landscape - horizontal alignment Two ways of printing Impact printer Impact printer Impact printer Impact printer Nonimpact printer Nonimpact printer Nonimpact printer Nonimpact printer Return

35Copyright © 2003 by Prentice Hall Impact Printers Physical contact with paper required to produce image Line printer Prints an entire line of a program at once Prints an entire line of a program at once Typically used with mainframe computers printing lengthy reports Typically used with mainframe computers printing lengthy reports Dot-matrix printer Has print head consisting of one or more columns of pins Has print head consisting of one or more columns of pins Pins form characters and images as pattern of dots Pins form characters and images as pattern of dots Return

36Copyright © 2003 by Prentice Hall Nonimpact Printers Places an image on a page without physically touching the page Laser printer Uses light beam to help transfer images to paper Uses light beam to help transfer images to paper Produces high-quality output at very fast speeds Produces high-quality output at very fast speeds Ink-jet printer Sprays dots of ink from jet nozzles Sprays dots of ink from jet nozzles Can print in both black and white and color Can print in both black and white and color Requires high-quality paper so ink does not smear Requires high-quality paper so ink does not smear Less expensive than laser printers Less expensive than laser printers Return

37Copyright © 2003 by Prentice Hall Voice Output Voice synthesizers convert data to vocalized sounds Two approaches Synthesis by analysis - analyzes actual human voice, records and plays back as needed Synthesis by analysis - analyzes actual human voice, records and plays back as needed Synthesis by rule - uses linguistic rules to create artificial speech Synthesis by rule - uses linguistic rules to create artificial speech Used in automated telephone-based customer service applications Useful when an inquiry would be followed by a short reply, such as a balance inquiry Useful when an inquiry would be followed by a short reply, such as a balance inquiry Return

38Copyright © 2003 by Prentice Hall Music Output Multimedia clips, games, videos include sight and sound Speakers placed on side of monitor Speakers placed on side of monitor Powered sub-woofers produce low-frequency sounds Powered sub-woofers produce low-frequency sounds Musical Instrument Digital Interface (MIDI) Rules for connecting musical instruments, synthesizers, and computers Rules for connecting musical instruments, synthesizers, and computers Allows users to set up home studios that rival capabilities of professional recording studios Allows users to set up home studios that rival capabilities of professional recording studios Return

39Copyright © 2003 by Prentice Hall Computer Output Microform (COM) Output of photographically reduced images on microfilm or microfiche Microfilm - images stored on continuous roll of film Microfilm - images stored on continuous roll of film Microfiche - images stored in rows and columns on a card Microfiche - images stored in rows and columns on a card Needs special reader Common uses Libraries store back issues of periodicals Libraries store back issues of periodicals Businesses store large volumes of historical records Businesses store large volumes of historical records Return

40Copyright © 2003 by Prentice Hall Terminals Combine input and output capabilities Dumb terminal Keyboard for input and monitor for output Keyboard for input and monitor for output No processing capability No processing capability Intelligent terminal Has limited memory and a processor Has limited memory and a processor Point-of-sale (POS) terminal Captures retail sales data when transaction takes place Captures retail sales data when transaction takes place

41Copyright © 2003 by Prentice Hall Computer Graphics Business graphics Business graphics Video graphics Video graphics Computer-aided design/computer-aided manufacturing Computer-aided design/computer-aided manufacturing (CAD/CAM) Computer-aided design/computer-aided manufacturing

42Copyright © 2003 by Prentice Hall Business Graphics A powerful way to impart information Colorful graphics, maps, and charts help managers compare data, spot trends, and make quicker decisions Colorful graphics, maps, and charts help managers compare data, spot trends, and make quicker decisions As underlying data changes, charts and graphs are instantly updated As underlying data changes, charts and graphs are instantly updated Return

43Copyright © 2003 by Prentice Hall Video Graphics A series of video images Displayed rapidly to give the impression of motion Displayed rapidly to give the impression of motion Used extensively in television Also used in computer and arcade video games Return

44Copyright © 2003 by Prentice Hall Computer-Aided Design/ Computer-Aided Manufacturing Creates two- and three- dimensional designs Performs engineering tests such as stress tests Serves as bridge between design and manufacturing Return

45Copyright © 2003 by Prentice Hall Ethics and Data Once data is in computer, there are many ways it can be used Ethical issues to ponder Is it ethical to use a computer to alter photographs? Is it ethical to use a computer to alter photographs? Is it ethical to erase messages that may be of interest to a party in a lawsuit? Is it ethical to erase messages that may be of interest to a party in a lawsuit? Is it ethical to use someone else’s data for your purposes? Is it ethical to use someone else’s data for your purposes?