Input and output, the user connection

1. The User Connection
C5- Input and Output

2. Adeyl Khan, Introduction to Computers
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
 E.g. Scanners- Flatbed, Sheetfed, Handheld
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3. Input Processing Time
Instant Reaction Input 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
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4. Adeyl Khan, Introduction to Computers
User Input: Getting Data using keyboard
 Originated from typewriter~ now extinct
 Can be unique to an industry~ POS
Keyboards
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Ergonomic Keyboards- Designed to reduce
or minimize repetitive strain injury of wrists
Provide more natural, comfortable
position of wrists, arms, and hands

5. Adeyl Khan, Introduction to Computers
User Input: Getting Data using Pointing Devices
 Point and click
 position a pointer on the screen
 Communicate commands by clicking buttons
 Common devices
 Mouse- Mechanical, Optical, Wireless
 Devices used for games
 Touchpad, pointing sticks
 Others
Trackball
Joystick

6. Adeyl Khan, Introduction to Computers
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
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7. Adeyl Khan, Introduction to Computers
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)
 Optical recognition devices
 Barcode Readers
 Other sources
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8. Adeyl Khan, Introduction to Computers
Common uses of Optical recognition devices
 Scanners at supermarkets
 Uses Barcodes
 Scanning text/documents
 Optical character recognition (OCR) software
required to convert picture into characters
 Document imaging - converts paper
documents to electronic versions
 Documents stored on disk
 Can be edited or processed by software

9. Adeyl Khan, Introduction to Computers
Other Input Sources
 Voice Input- User speaks to computer
 Speech recognition~ Most are speaker-dependent,
System “learns” user’s voice
 Digital Camera
 User takes photo that is stored on a chip
 Downloaded to computer
 Digital Photos
 Photos composed of many pixels of color
 Photos stored on removable memory card
 Use photo-editing software to enhance
 Store permanently on CDs or DVDs
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10. Adeyl Khan, Introduction to Computers
Other Input Sources: Digital Video
 Digital video consists of a 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
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11. Adeyl Khan, Introduction to Computers
Output: Information for the User
 Computer screens
 Screen is part of computer’s monitor
 Display text and graphics
 Screen output known as soft copy
 Computer Screen Technology
 Cathode ray tube (CRT), Flat-panel screens
 LCD, LED, OLED …
 Smart Displays (with a processor and communication equipment)
 Printers
 Voice output
 Music output
 Microform
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12. Adeyl Khan, Introduction to Computers
Output: Information for the User
 Major attribute affecting performance
 Scan rate~ Image refresh rate
 Color vs. Monochrome
 Resolution (clarity) of screen~ pixels- VGD, HD …
 Graphics standards exist
 Dot pitch ~ The amount of space between dots (PPI
…)
 Graphics card converts signals from the control
unit into the image the user sees
 Video memory- A high-speed form of RAM installed
on graphics card
12Video Frame Rate!

13. Adeyl Khan, Introduction to Computers
Graphic Standards: Resolution and color depth
width height
Mega-
pixels
Aspect
ratio
WXGA 1280 800 1.024 1.6
WSXGA /
WXGA+ 1440 900 1.296 1.6
WSXGA+ 1680 1050 1.764 1.6
WUXGA 1920 1200 2.304 1.6
UW-UXGA 2560 1080 2.765 2.37
WQHD 2560 1440 3.686 1.778
WQXGA 2560 1600 4.096 1.6
Color depth, also known as bit depth: 8-bit, 16-bit, 24-bit and 32-bit pixels
HDMI 1.3~ 30 bits (1.073 billion), 36 bits (68.71 billion), and 48 bits (281.5 trillion)

14. Adeyl Khan, Introduction to Computers
Impact printer and Nonimpact printer
 Impact Printers
 Physical contact with paper~ Line printer, Dot-
matrix printer
 Used for lengthy reports~ at banks
 Nonimpact Printers
 Prints without physically touching the page
 Laser printer~ Uses light beam
 Ink-jet printer~ Sprays dots of ink
 Ink smear!
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Decision
• Quality
• Speed
• Cost

15. Audio output
Music Output Voice 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
 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
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16. 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
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17. Adeyl Khan, Introduction to Computers
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
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18. Computer Graphics
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
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19. 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
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20. Adeyl Khan, Introduction to Computers
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 e-mail messages that may
be of interest to a party in a lawsuit?
 Is it ethical to use someone else’s data for your
purposes?
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21. Adeyl Khan, Introduction to Computers
!@#$%^&*

22. Adeyl Khan, Introduction to Computers
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
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