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 operatorโs
commands
๏ Sales rep enters an order on
a pad
๏ Characters displayed as
โtypedโ 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
4
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 โlearnsโ userโs 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 computerโs monitor
๏ Display text and graphics
๏ Screen output known as soft copy
๏ Computer Screen Technology
๏ Cathode ray tube (CRT), Flat-panel screens
๏ LCD, LED, OLED โฆ
๏ 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 โฆ
๏ Graphics standards exist
๏ Dot pitch ~ The amount of space between dots (PPI
โฆ)
๏ 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
โข Quality
โข Speed
โข 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 elseโs 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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Editor's Notes
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