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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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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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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Hinweis der Redaktion
Other devices
Pointing devices
Source data automation
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
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
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
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
Produce information on paper output~ hard copy
Orientation~ Portrait, Landscape
Two ways of printing
Impact printer
Nonimpact printer
Dot-matrix printer
Has print head consisting of one or more columns of pins
Pins form characters and images as pattern of dots