Transcript Computer Hardware

Computer Hardware
Peripheral Devices
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More Memory Types
Read Only Memory - ROM
 Complementary Metal-oxide
Semiconductor - CMOS
 Video Ram
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Buses: The CPU’s Data Highway
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Bus
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Electrical pathway used to move data between components
Local bus: Connects the CPU with the memory
Expansion bus: Connects the CPU with peripheral devices
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Bus Performance
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Bus clock speed
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Measured in bits
• 16 bits
• 32 bits
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Rate of speed data moves from
one location to another
Measured in Mhz (millions of
clock cycles per second)
Bus width
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The number of bits of data moved
on a bus at any one time
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Hard Disk Drive - Secondary Storage
Stores data and program
instructions
 Permanent (nonvolatile)
storage
 Storage capacities up to
250 GB and higher
 Transfers data in
milliseconds
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How a Hard Disk Works
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Composed of several
coated platters stacked
on a spindle
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Data saved to the disk:
polarized particles
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Between platters are
read/write heads that read
and write magnetized data
Platters
Read/write
head
Access arms
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Magnetic Storage
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Magnetic media:
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Track
Metal platters:
• Hard disks
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Plastic film:
• Floppy disks
• Zip disks
Sector
Tracks
 Sectors
 File Allocation Table
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Optical Storage
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Optical media:
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CD ROM
CD-R
CD-RW
DVD ROM
DVD-R
DVD-RW
Laser
Pit
Land
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Flash Drives and Cards
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Nonvolatile
Small size
Large capacity
Flash memory
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Flash card
Flash drive
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Input Devices
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Devices used to enter information or
instructions into the computer
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Keyboard
Mouse / pointing device
Microphone
Scanner
Digital camera
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Keyboard
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The QWERTY keyboard with enhanced features is
standard with most modern personal computers
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Dvorak Keyboard
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Puts the most commonly used keys at “home keys”
Reduces distance of finger stretches
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Specialty Keyboards
Laptop
Laptops
 PDAs
 Wireless
 Ergonomic
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PDA
Ergonomic
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Mouse
Standard
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Roller ball mouse
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Wireless
Trackball
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Less expensive
Harder to keep clean
Harder to control
Stationary on desk
Trackball
Optical
Optical mouse
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Needs no mouse pad
Doesn’t need cleaning
More expensive
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Other Input Devices
Handheld
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Scanners
Text
 Images
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Flatbed
Digital cameras
Images
 Video
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Camera
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Camcorder
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Inputting Sound
Microsoft Voice Recognition
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Microphone Input
Teleconferencing
 Voice over Internet
 Voice Recognition
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Output Devices
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Retrieving
information from the
computer
Output devices
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Softcopy (video,
sounds, control
signals)
Hardcopy (print)
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Monitor Types
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CRT Cathode Ray Tube
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Less Expensive
Use much more space
Uses more energy
Better viewing angles
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LCD Liquid Crystal Display
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More expensive
Uses far less space
More energy efficient
Less viewable from an angle
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Liquid Crystal Display
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Liquid crystal sandwiched between two
transparent layers form images
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Used for notebook computers, PDAs, cellular
phones, and personal computers
Polarizer
Color filter
Color filter
glass
Liquid
Crystal
Glass
polarizer
Backlight
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Monitors
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Things to consider:
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Resolution:
• Increasing resolution allows more
to be displayed
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Dot pitch:
• .31mm or less
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Refresh rate:
• 75 Hz or higher
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Printers
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Impact printers
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Dot-matrix
Non-impact printers
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Inkjet
Inkjet
Laser
Multifunction
Dot-matrix
Laser
Specialty printers
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Plotters
Thermal printers
Multifunction
Plotter
Thermal printer
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Non-impact Printers
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Ink Jet
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Less expensive device
Full color printing
Slower in pages per
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minute (PPM)
More expensive per page
in B&W
Laser
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More expensive device
Black and White (Color
lasers are very
expensive)
Faster in PPM
Less expensive in B&W
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Outputting Sound
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Speakers and
Headphones
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Expansion Cards
Adds functions
 Provides new connections for peripheral
devices
 Common types:
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Sound
 Modem
 Video (VGA)
 Network (NIC)
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Evaluating Ports
Ports are used to connect peripheral
devices to the computer
 Things to consider:
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Devices you want to use
 Ports needed for the devices
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Types of Ports
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Serial Port
 Transfers data one
bit at a time;
56Kbps
PS/2 Port
COM 1 Port
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PS/2
Connectors
Serial
Connector
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Types of Ports
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Parallel
 Transfers eight
bits of data
simultaneously;
12Mbps
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LPT 1 Port
Printer Cable Connector
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Types of Ports
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Universal serial bus
 Transfer speed up
to 480Mbps; Hot
swapping
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USB
Port
USB
Connector
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Types of Ports
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FireWire
 Transfer rate of
400 Mbps; Digital
cameras
FireWire
Port
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FireWire
Connector
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Types of Ports
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Ethernet
 Transfer rate of 100
Mbps; connects
computers to
networks
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Ethernet
Port
Ethernet
jack
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Types of Ports
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IrDA
 Transfer rate of 4
Mbps; Uses
infrared light waves
IrDA
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Types of Ports
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Bluetooth
 Transfer rate of 1
Mbps; radio waves
send data over
short distances
Bluetooth
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Types of Ports
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MIDI Port
Musical Instrument Digital Interface
 31.5 Kbps transfer rate
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Adding Ports
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Expansion cards:
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New port standards
Expansion hubs:
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Enables several
devices to be
connected to a port
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