Transcript computing ESSENTIALS

computing
ESSENTIALS
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Connectivity, the
Wireless Revolution,
and
Communications
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Competencies
Connectivity
Wireless Revolution
Communication systems
Connection devices
Transmissions and protocols
Network architecture
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Connectivity

Computer networks
that link people and
resources
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Other computers
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Large storage
devices

Internet
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Wireless Revolution
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Wireless and mobile
telephones
 Most dramatic change in
connectivity
 Connected all the time
anywhere
Originally voice
communication
Computer communications
 Bluetooth
 Device connections
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Communication Systems

Electronic systems that transmit and receive
information
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Basic elements
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Sending/Receiving device
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Communication channel
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Connection devices
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Data transmission specifications
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Communication Channels

Essential element of communication system
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Two categories
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Physical connection
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Wireless connection
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Wired Connections
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Telephone lines
 Twisted pair
 Old standard
• Coaxial cable
– Single solid-copper core
– 80 times faster
• Fiber-optic cable
– Light through glass
– 26,000 times faster
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Wireless Connections

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Microwave
 High-frequency radio waves
 Line-of-sight communication
 Relayed
Satellite
 Microwave relay stations
 Geostationary
 Large volume of data
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Connection Devices
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Modulator-demodulator
 Converts analog signal to digital signal
Speed in bits per second (bps)
External
Internal
PC Card
Wireless
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Connection Types
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Dial-up service
 Most popular, but slow
T1 – T4 lines
 Special high-speed lines
Digital subscriber line (DSL)
 Uses existing phone lines, fast
Cable
 Existing television cables
Satellite/air connection services
 Slower than DSL, but faster than dial-up
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Data Transmission

Bandwidth
 How much information can be transmitted
at one time
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Protocol
 Specific rules guiding the exchange of
information
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Bandwidth

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Measurement of capacity of the
communication channel
Categories
 Voiceband
 Standard phone line, dial-up
 Medium band
 Special leased lines
 Broadband
 High capacity transmissions
 DSL, cable, satellite
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Data Transmission Direction

Simplex
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Half-duplex
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One direction only
One direction at a time
Full-duplex
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Both direction simultaneously
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Protocols
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Set of communication rules for exchange of
information
Transmission control protocol/Internet
protocol (TCP/IP)
 Identification
 IP Address
 Domain name system (DNS)
 Reformatting
 Reassemble packets
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Networks
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Two or more connected computers that share
information and resources
Node
 Device connected to a network
Client
 Node that requests and uses resources
available from other nodes
Server
 Node that shares resources with other
nodes
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More Network Terms
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Network operating system (NOS)
 Software to control and coordinate activities
between nodes on a network
Distributed processing
 Computing power located and shared at
different locations
Host computer
 Large centralized computer, usually a
mainframe
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Network Architecture
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Arrangement of network communication
channel
Coordinates and shares resources
Topology
 Star network
 Bus network
 Ring network
 Hierarchical
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Star Network
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Bus Network
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Ring Network
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Hierarchical Network
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Strategies
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Ways to coordinate sharing of resources
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Most common
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Terminal network system
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Peer-to-peer network system
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Client/Server network system
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Enterprise computing
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Network Types
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Networks differ in geographical size
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Types of networks
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Local Area Network (LAN)
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Metropolitan Area Network (MAN)
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Wide Area Network (WAN)
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Local Area Networks
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Computers and devices linked in close
proximity to each other
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Typically use a bus form of organization
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Network gateways
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Network bridge
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Metropolitan Area Networks
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Link nodes and resources within the
geographical bounds of a city
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Link between buildings
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Cellular phones can extend the reach of a MAN
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Wide Area Networks
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Countrywide and worldwide network
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Use microwave relays and satellites
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Internet
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Widest of all WAN
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Look to Future
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Wireless robotic car
Toyota and Sony collaboration
 Pod
 Connects wirelessly to portable terminal
 Download
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songs from Internet
Use GPS to determine location
Communicate with other cars
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