Transcript Chapter 5

Chapter 5
Input and Output: The User
Connection
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Input vs. Output
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Users use input devices to provide data to
the computer
Output devices provide information to the
user
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Input devices
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Keyboard
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Function keys
Main keyboard
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Numeric keys and status lights
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Shift, control, Caps lock, tab
Num lock
Num lock, Insert, and Caps lock are
“toggle” keys
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Input Devices–Pointing Device
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Pointer
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Arrow
Insertion point or cursor
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Vertical bar
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Input Devices–Pointing Device
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Mouse
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Mechanical mouse
Optical mouse
Wireless mouse
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Input Devices–Pointing Device
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Trackball
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Input Devices–Pointing Device
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Touchpad
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Input Devices–Pointing Device
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Pointing stick
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Input Devices–Pointing Device
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Joystick
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Used often for
games
Can be used instead
of a mouse
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Input Devices–Pointing Device
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Graphics tablet
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Stylus
Puck
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Input Devices–Pointing Device
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Touch screens
Used in kiosks, a
self-contained
station
Kiosks are found in
libraries, museums,
airports, and
shopping malls
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Input Devices–Pointing Device
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Pen-based
computing
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Magnetic-Ink Character
Recognition (MICR)
A type of source
data automation
Used most by
the banking
industry
MICR numbers
printed on
checks
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SCANNERS
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Use laser light
3 types
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Flatbed scanner
Sheetfed scanner
Handheld scanner
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SCANNERS (Extra)
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Flatbed scanner
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Scans one sheet at a time
Can be used on books
Can scan 3-D objects
Take a lot of desk space
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SCANNERS (Extra)
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Sheetfed scanner
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Scans one sheet at a time
Cannot scan bound material
Take less space than flatbed
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SCANNERS (Extra)
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Handheld scanner
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Least expensive
Least accurate
May require several passes to get a
complete page scanned in
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Optical Recognition
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Optical Mark Recognition (OMR)
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For “reading” marks, lines, filled circles, etc
Optical Character Recognition (OCR)
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Analyzes an image, converts it into
characters
Can recognize handwritten characters if
done in block printing
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Optical Recognition
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Bar codes
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Universal Product Code (UPC) is one
standard
Other codes exist
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Voice Input
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Speech recognition
Speaker-dependent
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“trained” for a specific person’s voice
Speaker-independent
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Recognize any voice
Limited vocabulary
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Input Device
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Digital camera
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No film
Uses memory chips,
disks, or memory
sticks
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Output Devices
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CRT monitor
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Cathode Ray Tube
Raster scanning
3 colors of light:
red, green, and blue
produce all the
colors
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Output Devices
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CRT monitor quality
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Refresh rate (scan rate) = number of
Interlaced vs. non-interlaced
Resolution
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More pixels means higher resolution
Dot pitch
Size of monitor
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Output Devices
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Flat Panel screen
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Liquid crystal display (LCD)
Active matrix (TFT)
Passive matrix
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Computer Output
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Monitor
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Softcopy
Printer
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Hardcopy
Portrait vs. landscape
Resolution in dpi (dots per inch)
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Computer Output
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Voice output
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Speech synthesis
Synthesis by analysis
Synthesis by rule
Music and sound output
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MIDI
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Computer Output
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Graphics cards – provide output to a
monitor
Have memory chips on the card
Graphics standards
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SVGA - Super Video Graphics Array
XGA – Extended Graphics Array
XGA supports more simultaneous colors
than SVGA
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Output Devices
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Dot-matrix printer
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Impact
Pins striking a ribbon against paper
Used for multiple part forms
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Output devices
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Laser printer
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Non-impact
Light beam helps transfer images to paper
High quality
Uses toner and technology similar to a
photocopier
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Output Devices
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Ink-jet printer
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Non-impact
Spray ink onto paper
Good quality
Most can print in color
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Computer Terminal
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Dumb terminal
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Intelligent terminal
Keyboard, monitor, memory
 Some processing capability
Both dumb and intelligent terminals must be
connected to a “host” or server computer
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Keyboard and monitor
No processing capability
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Point-of-sale terminal (POS)
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Specialized input and output devices
The “cash register” at a supermarket is a
POS
Input through keyboard, scale, plus one or
more scanners
Output to one or more display devices plus
receipt printer