1. Computers: Tools for an Information Age
Chapter 5
Input and Output: The User Connection

2. 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

3. 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

4. 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
Also can be separated by time, distance, or both

5. Instant Reaction 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

6. Input and Output Separated
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

7. Input: Getting Data from the User to the Computer
Keyboard
Pointing devices
Source data automation

8. Keyboard Similar to typewriter keyboard Can be unique to an industry
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

9. Ergonomic Keyboards
Designed to reduce or minimize repetitive strain injury of wrists
Provide more natural, comfortable position of wrists, arms, and hands

10. Anatomy of a Keyboard

11. Pointing Devices Used to position a pointer on the screen
Communicate commands to operating system by clicking a button
Common devices
Mouse
Devices used for games
Devices used in laptops
Others

12. The First Mouse Invented by Doug Englebart at SRI, 1963/4
Doug Engelbart invented the computer mouse in as part of an experiment to find better ways to point and click on a display screen. It was made in a shop at SRI. The casing was carved out of wood. The mouse had only one button - that was all there was room for.

13. Mouse The most common pointing device Several types
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

14. Trackball and Joystick
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

15. Touchpad and Pointing Stick
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

16. Other Pointing Devices
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

17. Source Data Automation
Use of special equipment to collect data at the source
Primary areas
Magnetic-ink character recognition (MICR)
Optical recognition devices
Other sources

18. 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
Amount added by MICR inscriber when check is cashed

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

20. Common Uses Scanners at supermarkets
Document imaging - converts paper documents to electronic versions
Documents stored on disk
Can be edited or processed by software

21. Scanners Flatbed scanner Sheetfed scanner Handheld 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

22. Other Optical Recognition Methods
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

23. Other Sources
Voice input
Digital cameras
Video input

24. Voice Input User speaks to computer Most are speaker-dependent
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

25. Digital Camera 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

26. 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

27. Output: Information for the User
Computer screens
Printers
Voice output
Music output
Microform

28. Computer Screen Technology
Screen is part of computer’s monitor
Screen output known as soft copy
Intangible and temporary
Common forms
Cathode ray tube (CRT)
Flat-panel screens
Smart displays

29. CRT Screens 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

30. 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
Graphics standards
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

31. 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

32. Flat-Panel Screens Liquid crystal display (LCD)
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
Different flat-panel technologies

33. LCD Technologies Active-matrix Passive-matrix Gas plasma
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

34. 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

35. Printers Produce information on paper output Orientation settings
Printed output known as hard copy
Orientation settings
Portrait - vertical alignment
Landscape - horizontal alignment
Two ways of printing
Impact printer
Non-impact printer

36. Impact Printers Physical contact with paper required to produce image
Line printer
Prints an entire line of a program at once
Typically used with mainframe computers printing 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

37. Non-impact Printers
Places an image on a page without physically touching the page
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 from jet nozzles
Can print in both black and white and color
Requires high-quality paper so ink does not smear
Less expensive than laser printers

38. 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

39. 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

40. Computer Output Microform (COM)
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

41. 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

42. Computer Graphics Business graphics Video graphics
Computer-aided design/computer-aided manufacturing (CAD/CAM)

43. Business 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

44. Video Graphics A series of video images Used extensively in television
Displayed rapidly to give the impression of motion
Used extensively in television
Also used in computer and arcade video games

45. 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

46. 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?