Transcript Local Area Networks and E-Mail

CSCI 1101 Intro to
Computers
6. Local Area
Networks
ACS160 - Chapter 7
Local Area Networks
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A computer network is a collection of
computers and other devices that
communicate to share data, hardware and
software.
Local area network (LAN) - a network located
in a limited area.
 found
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in most businesses
Wide area network (WAN) - a network that
covers a large geographical area
ACS160 - Chapter 7
Benefits of Networking
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A local area network makes a stand-alone
computer a workstation on a network.
The workstation provides you with:
 your
computer’s local resources
hard drive, software
 printer

 access
to network resources
software
 storage space
 other printers

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ACS160 - Chapter 7
Typical Network Resources
Network nodes
include workstations
printers, and
servers.
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ACS160 - Chapter 7
Gaining Access to Networks

You typically cannot use network resources
until you log into the network.
 provide

user ID and password
User account
 provides
access to network
 accumulates information about network use
 tracks when you log in and out
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Password Considerations
Use these tips to
select a secure
password.
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ACS160 - Chapter 7
What is drive mapping?
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Workstation gains access to the server
when the server hard drive is “mapped” to a
drive letter.
Drive mapping - network term for assigning
a drive letter to a network server disk drive.
 many
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use the letter F
Window’s Neighborhood Network is a utility
that helps you see your workstation’s
network drive mapping.
ACS160 - Chapter 7
Executing programs on a Network
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When you start a program that is stored on a LAN, the
program is copied to your workstation’s RAM, then
runs normally.
With proper licensing, many users on the same
network can use the same program simultaneously,
also known as sharing.
Sharing is effective because:


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less disk storage space required
easier to update software
less expensive
ACS160 - Chapter 7
Where to store data files

Advantages to storing data files on a server:
 can
access from any computer on network
 other network users can access files

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option of restricting access
File locking - precaution that locks an open
file so other users cannot open it at the
same time
ACS160 - Chapter 7
Printer Issues
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Default printer printer you most
frequently use
One way to
select a different
printer is to
select a printer
using the
Printers dialog
box.
ACS160 - Chapter 7
How to physically connect to a
network
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A network interface card (NIC) is the key
hardware component for connecting a
computer to a local area network.
 small
circuit board that sends data to and from
workstation to network
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Different networks use different NICs.
Popular network types include Ethernet and
Token Ring.
ACS160 - Chapter 7
Network Cabling

Today’s networks use twisted-pair cable
 UTP
(unshielded twisted pair
 STP (shielded twisted pair)
 looks similar to telephone cable
 has square plastic RJ-45 connector
Twisted-pair cable
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ACS160 - Chapter 7
More network cabling options

Another option is coaxial cable
 resembles
cable-TV cable
 round, silver BNC connector
Coaxial cable
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ACS160 - Chapter 7
Non-wired network connections

Wireless networks use radio or infrared
signals to transmit data from one network
device to another.
 handy
in environments where wiring is difficult to
install

historical buildings
 provide
mobility
 good for temporary installations
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ACS160 - Chapter 7
Making the connection
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On most of today’s networks, the cable from a
workstation NIC connects to a network hub, a
device that joins communication lines together.
A hub serves as
a central connection point
for workstation and server
cables.
ACS160 - Chapter 7
Where does the actual processing
occur?
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When connected to a network, the device that
processes your data depends on the types of
servers.
 dedicated
servers
 non-dedicated servers
 print servers
 application servers
 host computers
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ACS160 - Chapter 7
Client Server issues
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Application server - computer that runs a
specific application software package
 also
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referred to as client/server architecture
An application server splits processing
between the workstation (client) and the
network (server).
ACS160 - Chapter 7
Typical client/server work issues
An application server
typically runs database
software and performs
database functions as
requested by the
workstations.
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Centralized processing systems
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Some networks include a host computer, a
minicomputer or a mainframe with attached
terminals.
 all
processing takes place on the host
 terminals only display results of processing
 also known as a time-sharing system
 Cyrix processing systems use this model
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Terminal emulation software connects a
microcomputer to a host
ACS160 - Chapter 7
How networks communicate
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Today’s computers include software necessary
to communicate with a network.
The software handles the communication
between your workstation and the network
server.
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Managing the network process
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Network operating system (NOS) software
 manages
network resources
 controls flow of data
 maintains security
 tracks user accounts
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Network operating system has two
components
 network
server software
 network client software
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Network software components
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Network server software (installed on file server)

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controls file access from the server’s hard disk
manages print queue
tracks user data
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Network client software (installed on workstation)

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IDs and passwords
gathers login information
handles drive mapping
directs printouts to network printer
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What can I run on a network?
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Most software designed for stand-alone
computers can be installed on a network
server.
Some software has built-in networking
features that only appear when software is
installed on network.
 ability
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to send a file to another network user
ACS160 - Chapter 7
Network software licensing
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Using a single-user license for multiple users
typically violates software’s copyright.
Software publishers offer a network license
that allows use by multiple people on a
network.
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Group-based processing
environments
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Groupware is application software that supports
collaborative work by managing:

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Workflow software - automates the process of
electronically routing documents from one person to
another in a specified sequence
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schedules
shared documents
intra-group communications
based on “information-centered model
based on a “process-centered model”
ACS160 - Chapter 7
How e-mail is communicated
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E-mail messages
are stored on a
server and
forwarded to you
when you want to
read it.
(store-and-forward
technology)
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How e-mail gets to other systems
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A gateway is an electronic link to other e-mail
systems that allows you to send e-mail to
people on other networks.
 transferred
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through the gateway
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Managing e-mail effectively

Tips for using e-mail
 read
mail regularly
 delete messages after you read them
 you don’t have to reply to every e-mail
 reply to one person instead of entire group
 think before you send
 don’t write anything confidential
 don’t get sloppy
 use proper netiquette
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