C5- Input and Output, The User Connection

How Users See Input and Output  Users submit data (input) to the computer to get processed information (output)  Output can be instant reaction to inputinstant reaction  Also can be separated by time, distance, or bothseparated by time 2

Instant ReactionInput and Output Separated  Items scanned at supermarket  Produce item name and price at counter  Forklift operator speaks to computer  Forklift obeys operator’s commands  Sales rep enters an order on a 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  Data on checks input into bank computer  Computer processes entries once a month to prepare statements  Charge-card transactions provide input  Processed monthly to produce customer bills  Water samples collected and input into computer  Used to produce reports that show patterns of water quality 3

User Input: Getting Data using keyboard  Similar to typewriter keyboard  May be part of a personal computer  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  Ergonomic keyboards Ergonomic keyboards 4 Pointing devices Source data automation

Anatomy of a Keyboard 5 Designed to reduce or minimize repetitive strain injury of wrists Provide more natural, comfortable position of wrists, arms, and hands

User Input: Getting Data using Pointing Devices  Used to position a pointer on the screen  Communicate commands to operating system by clicking a button  Common devices  Mouse Mouse  Devices used for games Devices used for games  Devices used in laptops Devices used in laptops  Others Others 6

 The most common pointing device  Movement on flat surface causes movement of pointer on screen  Several types  Mechanical - small ball on underside rolls as mouse is moved  Optical - uses a light beam to monitor mouse movement  Cordless - uses either infrared or radio waves, rather than a cord, to connect to computer 7

 Trackball  Variation on mechanical mouse  User rolls the ball directly  Often built into laptop computers  Joystick  Short lever with handgrip  Distance and speed of movement controls pointer’s position  Pressing trigger causes actions to take place 8

 Touchpad  Rectangular pressure- sensitive pad  Sliding finger across pad moves pointer  Tapping with finger recognized as click  Pointing stick  Small pressure- sensitive post mounted in center of keyboard  Pushing post in any direction moves pointer 9

 Graphics tablet  User moves stylus or puck across board  Used to create or trace precise drawings  Touch screen  Allow user to touch items on screen  Position of finger on screen determines item to be input into system  Used at kiosks in public places such as malls  Pen-based computing  Use pen-like stylus to input data  Often used in PDAs or pocket PCs 10 Return

User Input: Getting Data using Source Data Automation  Use of special equipment to collect data at the source  Primary areas  Magnetic-ink character recognition (MICR) Magnetic-ink character recognition  Optical recognition devices Optical recognition devices  Other sources Other sources 11 Return

 Uses a machine to read characters made of magnetized particles  Banking industry is predominant user  Characters preprinted on lower left-hand side of check  Amount added by MICR inscriber when check is cashed 12 Return

Optical Recognition  Uses a light beam to scan data and convert to electrical signals  Common uses Common uses  Scanners are the most common form Scanners  Other optical recognition methods Other optical recognition methods 13 Return

Common UsesScanners  Scanners at supermarkets  Document imaging - converts paper documents to electronic versions  Documents stored on disk  Can be edited or processed by software  Flatbed scanner  Typically scans one page at a time  Can be used to scan large bound documents  Sheetfed scanner  Motorized rollers feed sheet across scanner head  Handheld scanner  Smallest and least accurate  Optical character recognition (OCR) software required to convert picture into characters 14

 Optical Mark Recognition  Machine senses marks on piece of paper  Optical character recognition  Wand reader reads characters in special typeface  Bar Codes  A series of vertical marks  Represents a unique code  Universal Product Code (UPC) used as standard in supermarkets 15

Voice InputDigital Camera  User speaks to computer  Speech recognition devices convert spoken words into binary digits  Most are speaker-dependent  System “learns” user’s voice  Types of systems  Discrete word systems - user must pause between words  Continuous word systems - user can speak normally  User takes photo that is stored on a chip  Photo can be downloaded to computer  Use photo-editing software to enhance  Store permanently on CDs or DVDs  Photos composed of many pixels of color  Photos stored on removable memory card 16

Video Input  Digital video consists of series of still frames  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 17

Computer Screen Technology  Computer screens Computer screens  Printers Printers  Voice output Voice output  Music output Music output  Microform Microform  Screen is part of computer’s monitor  Screen output known as soft copy  Intangible and temporary  Common forms  Cathode ray tube (CRT) Cathode ray tube (CRT)  Flat-panel screens Flat-panel screens  Smart displays Smart displays 18

CRT ScreensFactors Affecting Performance  Display text and graphics  Most are in color  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  Scan rate  Image refresh rate  Resolution (clarity) of screen  Measured in pixels- more pixels, the higher the resolution  Graphics standards exist Graphics standards exist  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 19

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  Other varieties of SVGA exist  Support 16 million colors  The number of colors that can be displayed depends on amount of video memory

Display screens  Flat-Panel Screens  LCD Technologies  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 21

 Produce information on paper output~ hard copy  Orientation~ Portrait, Landscape  Two ways of printing  Impact printer Impact printer  Nonimpact printer Nonimpact printer 22

Impact PrintersNonimpact Printers  Impact Printers  Physical contact with paper  Line printer  Used for lengthy reports  Dot-matrix printer  Has print head consisting of one or more columns of pins  Pins form characters and images as pattern of dots  Places an image on a page without physically touching the page  Laser printer  Uses light beam to help transfer images to paper  High-quality, high speed  Ink-jet printer  Sprays dots of ink from jet nozzles  Requires high-quality paper so ink does not smear  Less expensive than laser printers 23

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 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 24

Music Output  Multimedia clips, games, videos include sight and sound  Speakers placed on side of monitor  Powered sub-woofers produce low-frequency sounds  Musical Instrument Digital Interface (MIDI)  Rules for connecting musical instruments, synthesizers, and computers  Allows users to set up home studios that rival capabilities of professional recording studios 25 Return

 Output of photographically reduced images on microfilm or microfiche  Microfilm - images stored on continuous roll of film  Microfiche - images stored in rows and columns on a card  Needs special reader  Common uses  Libraries store back issues of periodicals  Businesses store large volumes of historical records 26 Return

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  Point-of-sale (POS) terminal  Captures retail sales data when transaction takes place 27

Business Graphics Video Graphics  A powerful way to impart information  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  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 28 Computer-aided design/computer-aided manufacturing Computer-aided design/computer-aided manufacturing (CAD/CAM)

 Creates two- and three-dimensional designs  Performs engineering tests such as stress tests  Serves as bridge between design and manufacturing 29

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 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? 30

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  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 31