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Interacting with Computer
This lesson includes the following sections:
The Keyboard
The Mouse
Variants of the Mouse
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A standard computer keyboard has about 100 keys.
Most keyboards use the QWERTY layout, named for
the first six keys in the top row of letters.
The Keyboard - Standard Keyboard Layout
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5. Cursor-movement keys
4. Modifier keys
3. Function keys
2. Numeric keypad
1. Alphanumeric keys
Most keyboards have keys arranged in five groups:
The Keyboard - Standard Keyboard Layout
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* * * * *
The Keyboard - Standard Keyboard Layout
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The Keyboard - How a Keyboard Works
Key Board
Keyboard Controller Keyboard
BufferSystem Software
(Operating System)
CPU
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The Mouse
All modern computers have a variant
Allows users to select objects
The mouse is a pointing device. You use
it to move a graphical pointer on the
screen.
The mouse can be used to issue
commands, draw, and perform othertypes of input tasks.
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The Mouse - Mouse Techniques
1. Pointing; Move the mouse to move the on-screen pointer.
2. Clicking; Press and release the left mouse button
once.
3. Double-clicking; Press and release the left mouse
button twice.
4. Dragging; Hold down the left mouse button as youmove the pointer.
5. Right-clicking; Press and release the right mouse button.
Using the mouse involves five techniques:
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The Mouse
Mechanical mouse
Rubber ball determines direction and speed
The ball often requires cleaning
Optical mouse Light shown onto mouse pad
Reflection determines speed and direction
Requires little maintenance
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The Mouse
Benefits
Pointer positioning is fast
Menu interaction is easy
Users can draw electronically
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Variants of the Mouse
Trackballs
Upside down mouse
Hand rests on the ball
User moves the ball
Uses little desk space
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Variants of the Mouse
Track pads
Stationary pointing
device
Small plastic
rectangle
Finger moves across
the pad
Pointer moves with
the pointer Popular on laptops
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Variants of the Mouse
Track point
Little joystick on the keyboard
Move pointer by moving the joystick
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Inputting Data In Other Ways
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Devices for the Hand
Pen based input
Tablet PCs, PDA
Pen used to
write data
Pen used as
a pointer
Handwriting
recognition
On screen keyboard
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Devices for the hand
Touch screens
Sensors determine
where finger points
Sensors create an
X,Y coordinate
Usually presents a
menu to users
Found in cramped or
dirty environments
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Devices for the hand
Game controllers
Enhances gaming experience
Provide custom input to the game
Modern controllers offer feedback Joystick
Game pad
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Optical Input Devices
Allows the computer to see input
Bar code readers
Converts bar codes to numbers
UPC code
Computer find number in a database
Works by reflecting light
Amount of reflected light indicates number
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Optical Input Devices
Image scanners
Converts printed media into electronic
Reflects light off of the image
Sensors read the intensity Filters determine color depths
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Optical input devices
Optical character recognition (OCR)
Converts scanned text into editable text
Each letter is scanned
Letters are compared to known letters Best match is entered into document
Rarely 100% accurate
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Audiovisual Input Devices
Microphones
Used to record speech
Speech recognition
Understands human speech Allows dictation or control of computer
Matches spoken sound to known phonemes
Enters best match into document
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Audiovisual Input Devices
Musical Instrument Digital Interface
MIDI
Connects musical instruments to computer
Digital recording or playback of music Musicians can produce professional results
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Audiovisual Input Devices
Digital cameras
Captures images electronically
No film is needed
Image is stored as a JPG file Memory cards store the images
Used in a variety of professions
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Output Devices
Hard copy output :
The data consisting of text or
graphics that is obtained as printouts or
microfilm using printers or plotters isknown as hardcopy.
Soft copy output:
The data that is stored in a storagedevice such as floppy disk, hard disk,
CD-ROM magnetic tape and so on is
called softcopy.
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Monitors
Most common output device
Connects to the video card
Categorized by color output
Monochrome
One color with black background
Grayscale
Varying degrees of gray Color
Display 4 to 16 million colors
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Monitors
Cathode Ray Tube (CRT)
Most common type of monitor
Electrons fired from the back
Electrons excite phosphor to glow Phosphor is arranged in dots called pixels
Dot mask ensures proper pixel is lit
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CRT Monitors
Electron Gun
Magnetic Yoke
Phosphor coated screen
Electron beam
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Monitors
CRT color
Phosphor dots arranged in triads
Red, green, and blue dots
Three colors blend to make colors Varying the intensity creates new colors
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Monitors
CRT drawbacks
Very large
Very heavy
Use a lot of electricity
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Monitors
Liquid Crystal Display (LCD)
Commonly found on laptops
Desktop versions exist
Solve the problems of CRT Fluorescent lights provide illumination
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Monitors
Passive matrix LCD
Pixels arranged in a grid
Pixels are activated indirectly
Row and column are activated Animation can be blurry
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Monitors
Active matrix LCD
Each pixel is activated directly
Pixels have 4 transistors
One each for red, green, blue One for opaqueness
Transistors arranged in a thin film
Animation is crisp and clean
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Monitors
Drawbacks to LCD
More expensive than CRT
Must sit directly in front of screen
Can be more fragile than CRT
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Copyright 2006 by The McGraw-Hill Companies, Inc. All rights reserved.McGraw-Hill Technology Education
Chapter 4B
PrintingPrinting
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Commonly Used Printers
Impact printers
Generate output by striking the paper
Uses an inked ribbon
Non-impact printers Use methods other than force
Tend to be quiet and fast
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Commonly Used Printers
Dot matrix printers
Impact printer
Used to print to multi-sheet pages
Print head strikes inked ribbon Line printers
Band printers
Speed measured in characters per second
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Dot Matrix Print Head
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Dots Per Inch
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Commonly Used Printers
Laser printer Non-impact printer
Produces high quality documents
Color or black and white Print process
Laser draws text on page
Toner sticks to text
Toner melted to page
Speed measured in pages per minute
Quality expressed as dots per inch
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Commonly Used Printers
All-in-one peripherals Scanner, copier, printer and fax
Popular in home offices
Prices are very reasonable
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Comparing Printers
Determine what you need
Determine what you can spend
Initial cost
Cost of operating
Image quality
Speed
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High-Quality Printers
Plotters Large high quality blueprints
Older models draw with pens
Operational costs are low Output is very slow
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Copyright 2006 by The McGraw-Hill Companies, Inc. All rights reserved.McGraw-Hill Technology Education
End of ChapterEnd of Chapter
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Copyright 2006 by The McGraw-Hill Companies, Inc. All rights reserved.McGraw-Hill Technology Education
Operating SystemBasics
Operating SystemBasics
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Functions of Operating Systems
Provide a user interface
Run programs
Manage hardware devices
Organized file storage
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Types of Operating Systems
Real-time operating system Very fast small OS
Built into a device
Respond quickly to user input MP3 players, Medical devices
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Types of Operating Systems
Single user/Single tasking OS One user works on the system
Performs one task at a time
MS-DOS and Palm OS Take up little space on disk
Run on inexpensive computers
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Types of Operating Systems
Single user/Multitasking OS User performs many tasks at once
Most common form of OS
Windows XP and OS X Require expensive computers
Tend to be complex
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Providing a User Interface
User interface How a user interacts with a computer
Require different skill sets
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Providing a User Interface
Graphical user interface (GUI) Most common interface
Windows, OS X, Gnome, KDE
Uses a mouse to control objects Uses a desktop metaphor
Shortcuts open programs or documents
Open documents have additional objects
Task switching
Dialog boxes allow directed input
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Graphical User Interface
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Providing a User Interface
Command line interfaces Older interface
DOS, Linux, UNIX
User types commands at a prompt User must remember all commands
Included in all GUIs
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Command Line Interface
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Managing Hardware
Programs need to access hardware
Interrupts
CPU is stopped
Hardware device is accessed
Device drivers control the hardware
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Organizing Files and Folders
Organized storage
Long file names
Folders can be created and nested
All storage devices work consistently
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Copyright 2006 by The McGraw-Hill Companies, Inc. All rights reserved.McGraw-Hill Technology Education
Survey of PC and
Network Operating
Systems
Survey of PC and
Network Operating
Systems
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PC Operating Systems
Microsoft Windows is the most popular Installed more than other OS combined
Installed on about 95% of computers
Apple and Linux represent the other 5%
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PC Operating Systems
DOS Disk Operating System
Single user single-tasking OS
Command line interface 16-bit OS
Powerful
Fast
Supports legacy applications
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PC Operating Systems
Windows NT Designed for a powerful system
32-bit OS
Very stable Windows NT Workstation
Single user multi tasking OS
Windows NT Server
Multi user multi tasking OS
Network operating system
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PC Operating Systems
Windows 9x 95, 98, and Millennium Edition (Me)
32-bit OS
Supported 16-bit programs well Very pretty not stable OS
Still found in large corporations
95 introduced the Start button
98 introduced active desktop
Me improved multimedia software
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PC Operating Systems
Windows 2000 Look of 9x with NT stability
Optimized for office and developers
Application software ran very well Entertainment software ran very poorly
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PC Operating Systems
Windows XP Microsofts newest desktop product
Different look from 2000
Many different versions Digital multimedia support was enhanced
Communications was enhanced
Mobile computing became a priority
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PC Operating Systems
UNIX Runs on all computer types
32- or 64-bit
Very stable and fast Command-line interface
Can cost thousands of dollars
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PC Operating Systems
Linux Free or inexpensive version of UNIX
32-bit OS
Very stable and fast Most flavors are open source
X Windows GUI
Command line interface is available
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Copyright 2006 by The McGraw-Hill Companies, Inc. All rights reserved.McGraw-Hill Technology Education
Chapter 9A
Network BasicsNetwork Basics
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Network Definition
Set of technologies that connectscomputers
Allows communication and collaboration
between users
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The Uses of a Network
Simultaneous access to data Data files are shared
Access can be limited
Shared files stored on a server Software can be shared
Site licenses
Network versions
Application servers
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Sharing Data
File server contains documentsFile server contains documents
used by other computers.used by other computers.
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The Uses of a Network
Personal communication Email
Instantaneous communication
Conferencing Tele conferencing
Videoconferencing
Audio-conferencing
Data-conferencing Voice over IP
Phone communication over network wires
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The Uses of a Network
Easier data backup Backup copies data to removable media
Server data backed up in one step
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Common Network Types
Local Area Network (LAN) Contains printers, servers and computers
Systems are close to each other
Contained in one office or building Organizations often have several LANS
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Common Network Types
Wide Area Networks (WAN) Two or more LANs connected
Over a large geographic area
Typically use public or leased lines Phone lines
Satellite
The Internet is a WAN
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Hybrid Network Types
Campus Area Networks (CAN) A LAN in one large geographic area
Resources related to the same organization
Each department shares the LAN
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Hybrid Network Types
Metropolitan Area Network (MAN) Large network that connects different
organizations
Shares regional resources A network provider sells time
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Hybrid Network Types
Home Area Network (HAN) Small scale network
Connects computers and entertainment
appliances Found mainly in the home
H b id N k T
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Hybrid Network Types
Personal Area Network (PAN) Very small scale network
Range is less than 2 meters
Cell phones, PDAs, MP3 players
H N t k A St t d
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How Networks Are Structured
Server based network Node is any network device
Servers control what the node accesses
Users gain access by logging in Server is the most important computer
H N t k A St t d
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How Networks Are Structured
Client/Server network Nodes and servers share data roles
Nodes are called clients
Servers are used to control access Database software
Access to data controlled by server
Server is the most important computer
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N t k T l i
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Network Topologies
Topology Logical layout of wires and equipment
Choice affects
Network performance Network size
Network collision detection
Several different types
N t k T l i
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Network Topologies
Packets Pieces of data transmitted over a network
Packets are created by sending node
Data is reassembled by receiving node
Packet header
Sending and receiving address
Packet payload
Number and size of data Actual data
Packet error control
N t k T l i
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Network Topologies
Bus topology Also called linear bus
One wire connects all nodes
Terminator ends the wires Advantages
Easy to setup
Small amount of wire
Disadvantages
Slow
Easy to crash
N t k T l i
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Network Topologies
Star topology All nodes connect to a hub
Packets sent to hub
Hub sends packet to destination
Advantages
Easy to setup
One cable can not crash network
Disadvantages One hub crashing downs entire network
Uses lots of cable
Most common topology
St T l
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Star Topology
N t k T l i
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Network Topologies
Ring topology Nodes connected in a circle
Tokens used to transmit data
Nodes must wait for token to send Advantages
Time to send data is known
No data collisions
Disadvantages Slow
Lots of cable
N t k T l i
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Network Topologies
Mesh topology All computers connected together
Internet is a mesh network
Advantage Data will always be delivered
Disadvantages
Lots of cable
Hard to setup
Mesh Topolog
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Mesh Topology
Network Media
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Network Media
Links that connect nodes Choice impacts
Speed
Security Size
Wire Based Media
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Wire Based Media
Twisted-pair cabling Most common LAN
cable
Called Cat5 or
100BaseT Four pairs of copper
cable twisted
May be shielded from
interference Speeds range from
1 Mbps to 1,000 Mbps
Wire Based Media
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Wire Based Media
Coaxial cable Similar to cable TV wire
One wire runs through cable
Shielded from interference Speeds up to 10 Mbps
Nearly obsolete
Wire Based Media
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Wire Based Media
Fiber-optic cable Data is transmitted
with light pulses
Glass strand instead
of cable Immune to
interference
Very secure
Hard to work with Speeds up to
100 Gbps
Wireless Media
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Wireless Media
Data transmitted through the air LANs use radio waves
WANs use microwave signals
Easy to setup
Difficult to secure
Network Hardware
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Network Hardware
Network interface cards Network adapter
Connects node to the media
Unique Machine Access Code (MAC)
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Network Hardware
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Network Hardware
Hubs Center of a star network
All nodes receive transmitted packets
Slow and insecure
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Network Hardware
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Network Hardware
Bridge Connects two or more LANs together
Packets sent to remote LAN cross
Other packets do not cross
Segments the network on MAC addresses
Network Hardware
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Network Hardware
Router Connects two or more LANs together
Packets sent to remote LAN cross
Network is segmented by IP address Connect internal networks to the Internet
Need configured before installation
Network Hardware
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Network Hardware
Gateway Connects two dissimilar networks
Connects coax to twisted pair
Most gateways contained in other devices
Network Cabling
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Network Cabling
Cabling specifications Bandwidth measures cable speed
Typically measured in Mbps
Maximum cable length
Connector describes the type of plug
Network Cabling
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Network Cabling
Ethernet Very popular cabling technology
10 Base T, 10Base2, 10Base5
Maximum bandwidth 10 Mbps Maximum distances100 to 500 meters
Network Cabling
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Network Cabling
Fast Ethernet Newer version of Ethernet
Bandwidth is 100 Mbps
Uses Cat5 or greater cable Sometimes called 100Base T
Requires a switch
Network Cabling
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Network Cabling
Gigabit Ethernet High bandwidth version of Ethernet
1 to 10 Gbps
Cat 5 or fiber optic cable Video applications
Network Cabling
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Network Cabling
Token ring Uses shielded twisted pair cabling
Bandwidth between 10 and 25 Mbps
Uses a multiple access unit (MAU) Popular in manufacturing and finance
Network Protocols
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Network Protocols
Language of the network Rules of communication
Error resolution
Defines collision and collision recovery Size of packet
Naming rules for computers
Network Protocols
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Network Protocols
TCP/IP Transmission Control Protocol/Internet
Protocol
Most popular protocol
Machines assigned a name of 4 numbers
IP address
209.8.166.179 is the White Houses web site
Dynamic Host Configuration Protocol Simplifies assignment of IP addresses
Required for Internet access
Network Protocols
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Network Protocols
Token ring Popular in manufacturing and finance
Nodes communicate when they have the
token
Chapter 9A
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Chapter 9A
End of ChapterEnd of Chapter