Transcript Technology in Action

Chapter Topics
Chapter 2
Looking at Computers:
Understanding the Parts
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Functions of a computer
Data versus information
Bits and bytes
Input devices
Output devices
System unit
Ergonomics
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Computers Are Data
Processing Devices
• Computer’s four major functions:
– Gathers data (users input data)
– Processes data into information
– Outputs data or information
– Stores data and information
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Data vs. Information
• Data: Representation of a fact, figure, or idea
• Information: Organized, meaningful data
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Bits and Bytes:
The Language of Computers
• Bit
– Binary digit
– 0 or 1
• Byte
– Eight bits
• Each letter, number, and character = a string
of eight 0s and 1s
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How Much Is a Byte?
Name
Abbreviation
Number of Bytes
Relative Size
Byte
B
1 byte
Can hold one character of data.
Kilobyte
KB
1,024 bytes (210 bytes)
Megabyte
MB
1,048,576 bytes (220 bytes)
Gigabyte
GB
1,073,741,824 bytes (230 bytes)
Can hold 1,024 characters or about
half of a double-spaced typewritten
page.
Can hold approximately 768 pages of
typed text.
Approximately 786,432 pages of text;
500 sheets of paper is approximately
2 inches, so this represents a stack
of paper 262 feet high.
Terabyte
TB
1,099,511,627,776 bytes (240 bytes)
This represents a stack of typewritten
pages almost 51 miles high.
Petabyte
PB
1,125,899,906,842,62 bytes (250
bytes)
Exabyte
EB
1,152,921,504,606,846,976 bytes
(260 bytes)
Zettabyte
ZB
1,180,591,620,717,411,303,424
bytes (270 bytes)
The stack of pages is now 52,000
miles high, or approximately onefourth the distance from the Earth to
the moon.
The stack of pages is now 52 million
miles high, or just about twice the
distance between the Earth and
Venus.
The stack of pages is now 52 billion
miles high, some 20 times the
distance between the Earth and
Pluto.
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Metric prefixes
prefix
abbrev
#
word
--
B
1 byte
kilo
KB
1,000 bytes
thousand
mega
MB
1,000,000 bytes
million
giga
GB
1,000,000,000 bytes
billion
tera
TB
1,000,000,000,000 bytes
Trillion
peta
PB
1,000,000,000,000,000 bytes
quadrillion
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Computer Hardware
Hardware:
Any part of the
computer you can
touch.
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Computer Software
• Software: Programs that enable
hardware to perform different tasks
– Application software
– System software
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Types of Computers
• Notebook: Portable computer
• Desktop: Used at a single location
• Mainframe: Supports hundreds of
users simultaneously
• Supercomputer: Performs complex
calculations rapidly
• Embedded: Self-contained computer
performing dedicated functions
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Input Devices
• Devices used to enter information or
instructions into the computer
– Keyboard
– Mouse/
pointing device
– Microphone
– Scanner
– Digital camera
– Stylus
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Keyboards
• The QWERTY
layout is standard
on most PCs
• Enhanced
keyboard features
include number,
function, and
navigation keys.
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Notebook Keyboard
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trackpoint
touchpad
number pad
Notebook keys –
fn key in
conjunction with
function key
does special
function such as
volume
trackpoint
Fn key
Touchpad
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Dvorak Keyboards
• Puts the most commonly used keys on “home keys”
• Reduces distance of finger stretches
• Not enough interest to change from QWERTY
though
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Virtual laser, Tablet and stylus
• Virtual laser
keyboard
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• Configurable
keyboard
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Digital pen
• Stores what you
“write”, later transfer
to computer
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Wireless RF keyboard
• With the RF (radio
frequency) wireless
technology, the keyboard
contains a transmitter that
transmits the radio waves
to a receiver that sits next
to the keyboard and is
attached to the tower.
(upto 100 ft)
• Bluetooth wireless
keyboard is a shorter
range wireless
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RF keyboard
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Mice
• Optical mouse
– Doesn’t need as dirty
– no mouse pad necessary
• Trackball
– Easier on wrists
– Stays stationary
on desk
• Wireless
– Use radio or light waves
• Integrated pointing device
– Touchpad
– Trackpoint
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Other Input Devices
• Scanners
– Text
– Images
• Digital cameras
Flatbed
scanner
Handheld scanner
– Images
– Video
Digital camera
Camcorder
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Other Input Devices
• Game controllers
• Touchscreens
– DS game
– Tablet PC (see pic)
• Digital pens
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Image Input
• Digital cameras,
camcorders, and cell
phones
– Pictures
– Video
• Webcams
– Live video
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Inputting Sound
• Microphones
used for:
– Podcasts
– Videoconferencing
– Internet phone
calls
– Speech
recognition
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Input Devices for the
Physically Challenged
• Visual impairments
– Voice recognition
– Keyboards with large keys
– On-screen keyboards
• Motor control issues
– Special trackballs
– Head-mounted devices
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Output Devices
• Send processed data out of the computer
– Monitors
– Printers
• Output devices make:
– Soft copies (video, sounds, control signals)
– Hard copies (print)
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Monitor Types and advantages
CRT Cathode Ray Tube
– Less expensive
– Better viewing angles
– More adjusting allowed of of
the resolution settings
– Better color accuracy
– Preferred for gaming
– A 17” monitor IS less than17”
– legacy
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LCD Liquid Crystal Display
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Price is dropping
Uses far less space
More energy efficient
More environmentally friendly
Less eye strain
A 17’’ monitor IS 17”
brighter
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LCD Monitor Features
• Screens are grids made up of millions of pixels.
– (pixel = picture elements, dots on screen)
– Each pixel is composed of red, blue, and green
subpixels
• LCDs: Liquid crystal, light waves, etc result in
variations of red, green blue colors of images
formed n scrn
(CRTs: Pixels illuminated by electron beam
that passes back/forth across screen.)
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LCD Quality Factors
(recommended measures in parentheses) :
• Resolution - depends on # of pixels on screen;
(native resolution is the maximum resolution)
• Viewing angle - poorer angles than the CRT
(degrades after 150 degrees)
• Contrast ratio - Diff between brightest white &
darkest black (400:1 or 1000:1)
• Brightness - amt of light when showing pure
white (300 cd/m2)
• Response time – time for pixel to change
color (smaller # better; for movies, games)
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Screen Size
• 21” monitor: 1680x1050 pixels (typical
resolution)
• 19” monitor: Some resolutions: 1440x900,
1280x1024
– Need 1920x1080 for hi-def movies
• Wide screen vs. standard 4:3 ratio; wide good
for 2 documents viewed at once...
• Large resolution fits more on screen (images are
smaller); Small res fits less (images are larger)
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Other Video Output
• Touch-screen monitors
– Double as both input and output devices
• Monitors w/ built-in cam, mic, card
reader, USB hub
• Data projectors
– Project a computer image to wall for
sharing with group
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Printers
• Impact printers
– Dot-matrix
• Nonimpact printers
– Inkjet
– Laser
• Specialty printers
– All-in-one
– Plotters
– Thermal printers
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Nonimpact Printers
• Inkjet
– Less expensive device
– Print high-quality color
images cost effectively
• Laser
– More expensive device
– Faster printing speed
– Color lasers are
becoming less expensive
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Nonimpact Printers
Inkjet and Laser
• Inkjet (spray tiny drops of ink. )
– Entry level model is less
expensive
• Laser (uses toner)
– Full color printing –
excellent choice for
– There are B & W laser
photo printing
printers and color
laser printers (Color
lasers very expensive)
– Excellent quality, quiet
When purchasing a printer consider price of
consumables (ex: cartridges and toner), speed (ppm,
pages per minute), resolution (dpi, dots per inch) ,
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memory, color
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The Motherboard
• CPU
• RAM (S+T)
• Expansion
cards and
slots
• Built-in
components
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Expansion Cards
• Add functions
• Provide new connections for peripheral
devices
• Common types:
– Sound
– Modem (telephone)
– Video (VGA or graphics)
– Network (NIC=network interface card)
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RAM vs. ROM
• Random access
memory (RAM):
– Stores instructions
and data
– Temporary
(volatile) storage
– Consists of several
memory cards or
modules
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• Read-only memory
(ROM):
– Stores start-up
instructions
– Permanent storage
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Memory Module
• Random access memory (RAM)
• Stores instructions and data temporarily
– (copy of program instructions and current files
goes into RAM)
• Temporary (volatile) storage
• Operates in nanoseconds
• Common size: 2-8GB
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Central Processing Unit (CPU)
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Referred to as the “brains” of the computer
Controls all functions of the computer
Processes all commands and instructions
Can perform billions of tasks per second
Common speed: 2-3 ghz (gigahertz)
3 ghz = ~ 3 billion machine cycles per sec
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CPU Performance Measures
• Speed - common 2-3 ghz
– 3 GHz ~ 3 billion machine cycles per sec
– Megahertz (MHz)
– Gigahertz (GHz);
• Cores (simultaneous paths executing instruct’s;
see picture on right)
– Single
– Dual
– Quad
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Drive Bays
• Internal drive bays:
– Cannot be accessed from
outside the system
– Are reserved for internal
hard drives
• External drive bays:
– Can be accessed from
outside the system
– CD or DVD drives
– Floppy and Zip drives
(legacy technology)
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The Front Panel
• Power control
• Drive bays
• Memory card
reader
• Productivity
ports
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Hard Drive
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Permanent storage
Internal or external versions
Stores data, program instructions as they are running
(Completes tasks in millisecs vs RAM’s nanosecs.)
(Spin rate: 5400, 7200 rpm)
Common: 500 GB, 640 GB, 1TB, 2TB
– (T=Tera, trillion)
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Optical Storage
• Compact discs (CDs)
• Digital video discs (DVDs)
• Blu-ray discs (BDs)
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Storage Media Capabilities
See p71 (8e), teacher notes
Typo: DVD
DL is 8.5 GB
not 88.5
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Flash Drives/Flash Memory
• Flash drives (jump
drives)
– Newer storage
alternative
– Plug into USB ports
• Flash memory cards
– Slide into slots in the
system
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Types of Ports
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USB
Serial and parallel
Audio and video
FireWire
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• Connectivity
– Ethernet
– Modem
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Ports for peripheral devices
Types of ports w/ speeds (= transfer rates):
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Serial 115K bps,
Parallel 500K bps
USB 480M bps (2.0)
USB 4800M bps (3.0)
Ethernet 100M,1000M bps
Tele. modem 56K bps
FireWire (or 1394)
400M bps, 800M bps, and
3.2G bps (= 3200M bps)
– Audio ports
– VGA (monitor), DVI, s-video
– HDMI
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Adding Ports
• Expansion cards:
– New port
standards
• Expansion hubs:
– Enable several
devices to be
connected to a
port
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Power Controls
Power-on button: Turns on system; Use
Shut Down procedure or may use Power
button to turn off.
• Called a cold boot when turned on for the first
time that day (Warm boot is restart)
• Keep computer on but use conservation
of energy: Sleep mode, Hibernate
• Only turn off computer if use it very little
• Change power settings: Control Panel
(icon view) > Power Options
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Ergonomics (1)
• Ergonomics – procedures,
equipment for minimizing injury
or discomfort while using the
computer (minimize RSI repetitive stress injury)
• Steps to follow:
– Position monitor correctly (eyse
at top of monitor)
– Use adjustable chair (back of
knees not pressed against
chair that is too high, feet on
floor)
– Wrists flat over keyboard, not
presses on edge of table
– Take breaks
– Ensure adequate lighting
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Ergonomics (2)
• Play PMPs (personal media players)
at 60 decibels or less
• Small screens – blink often, take a break
to focus at 8ft
• Backpack – place over both shoulders
not one
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Chapter 2 Summary Questions
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What are the 4 main functions of a computer?
What is the difference between data and information?
What are bits and bytes, and how are they measured?
What devices do you use to get data into the computer?
What devices do you use to get information out of the
computer?
What’s on the motherboard?
Where are programs and information stored?
How are devices connected to the computer?
How do you set up your computer to avoid strain and
injury?
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