Download BTT Unit – The Internet and Networks A. History and development of

Unit – The Internet and Networks
BTT
A. History and development of the Internet
Notes 1 – A brief History of the Internet and Definitions

The Internet is really a very large wide area network (WAN) connecting
computers and networks around the world. Millions of computers are
connected by telephone lines, cable lines, and satellites.

The Internet started in the 1960’s by the US Defense department. The
purpose was to set up a communication link that could survive a nuclear war or
natural disaster. This was done by setting up links between some government
and universities throughout various locations in the US. This consisted of a
backbone of cables to handle the traffic among the network. Originally, the
Internet was known as ARPANet (Advanced Research Projects Agency
Network).

Users of ARPANet used the network to share scientific and engineering
information. People started to find additional uses for the network – the
most popular being e-mail. This encouraged the expansion of the network
into Europe in the 1970’s and it continued to grow in use into the 1980’s

In 1983, ARPNet split up into 2 parts – ARPANet and MILNet. ARPANET
continued to be used by academics and universities and MILNet was used by
the military.

By the mid 1980’s, the speed of the ARPNet was not sufficient to handle the
communication traffic demand of its users. At this time a new network was
created by The National Science Foundation called NSFNet. NSFNet
connected supercomputers in various research and academic facilities. The
purpose was then to easily exchange information. ARPNet and NSFNet were
linked together but the faster speed of NSFNet resulted in ARPNet being
fully replaced by NSFNet by the early 1990’s.

The growth of the PC market and the interest of people to be able to use
computers to communicate resulted in rapid growth of the Internet during
the 1990’s. Since NSFNet was restricted to academic users it was up to
telecommunication companies such as Bell, AT&T, and Nortel to respond to
this demand by building new high speed backbones.
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
B.
These companies used the same communication language that was used by
ARPNet and NSFNet, referred to as TCP/IP (Transmission Control
Protocol/Internet Protocol)
What is the WWW
The birth of the World Wide Web (WWW) and the development of Web browser
software led to incredible growth of the Internet in the 1990’s.
Tim Berners-Lee developed the WWW in the early 1980’s at the European Laboratory for
Particle Physics (CERN) in Switzerland. The WWW is more commonly known as the Web
The WWW is a collection of millions of hypertext documents. Hypertext documents are
most commonly written in Web authoring language called HTML (Hypertext Markup
Language). These documents can contain built in applications and links to databases in
addition to text, sound, graphics, and animation. Hypertext Transfer Protocol (HTTP) is
the set of rules that control how documents written in HTML are going to be interpreted
and displayed through a browser.
A Web browser is a program that will interpret hypertext documents on the Web and
display them on the screen.
C. Anatomy of a Web Site Address
A Web site address is also referred to as a universal (or uniform) resource locator or
URL.
Punctuation
“colon slash slash”
Domain Name
Path and file name
(optional)
http://www.myaddress.com/people/btt.html
Transfer
protocol.
Hostname
(optional).
Second-level
Domain
Top-level
Domain
This is the
most
common
protocol
This is the
server name,
which is
often www
This is
usually the
2
organization’s
name as
This
describes the
type of
domain.
Unit – The Internet and Networks
BTT
D.
Internet Search Engines and search tips
Notes
 A search engine is a computer program that electronically searches the Web
looking for HTML documents. These programs are referred to as Web crawlers,
spiders, or indexing robots.

A search engine works by searching “key words” that you enter and looks for these
in web pages. The search engine then prioritizes the results and displays the
address of web pages that contain your key words.

There are two types of search engines;
 Single-search engines such as Google, Yahoo, AltaVista
 Meta-search engines that take your search request and in turn submit it to
numerous search engines simultaneously. These include Dogpile and
metacrawler.
Search Tips
The Five-Step Search Strategy We Recommend
Step #1. Analyze your topic to decide where to begin
Click here for a printable FORM you may use to Analyze Your Topic (pdf file).
PDF files are
supported in Netscape 4.x and some other browsers. To view, search, or print the PDF files, you will need to use Adobe®
Acrobat® Reader software, which is available free from Adobe if you need it.
have distinctive words or phrases?
methernitha, unique meaning
"affirmative action", specific, accepted meaning in word cluster
have NO distinctive words or phrases you can think of? You have only
common or general terms that get the "wrong" pages.
"order out of chaos", used in too many contexts to be useful
sundiata, retrieves a myth, a rock group, a person, etc.
seek an overview of a broad topic?
victorian literature, alternative energy sources
Does your
topic...
specify a narrow aspect of a broad or common topic?
automobile recyclability, want current research, future designs, not how to recycle or oil
recycling or other community efforts
have synonymous, equivalent terms, or variant spellings or endings that
need to be included?
echinoderm OR echinoidea OR "sea urchin", any may be in useful pages
"cold fusion energy" OR "hydrogen energy", some use one term, some the other; you
want both, although not precisely equivalent
millennium OR millennial OR millenium OR millenial OR "year 2000", etc.
Pages you want may contain any or all.
Make you feel confused? Don't really know much about the topic yet? Need
guidance?
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BTT
Unit – The Internet and Networks
Step #2. Pick the right starting place using this table:
Specialized
YOUR
Subject
Databases
Find an
TOPIC'S
Search Engines
Directories
"Invisible
Expert
FEATURES:
Web"
Enclose phrases in
Distinctive or " ".
Search the broader
word or
Test run your
concept, what your
phrase?
word or phrase in term is "about."
Google.
Use more than one
NO distinctive
Try to find
term or phrase in "
words or
distinctive terms in Want data?
" to get fewer
phrases?
Subject Directories Facts?
Look for a
results.
Statistics?
specialized
Look for a
All of
subject
Seek an
NOT
specialized Subject
directory on
overview?
RECOMMENDED Directory focused something?
One
of
many
your topic.
on your topic
like things?
E-mail the
Narrow aspect
Look for a
Schedules?
author of a
of broad or AltaVista's Boolean Directory focused
Maps?
good page
common
searching
on the broad
Look for a
you find.
topic?
subject.
specialized
Ask a
Choose search
database
on
discussion
Synonyms,
engines with
the
Invisible
group or
equivalent
NOT
Boolean OR, or
Web.
expert.
terms,
RECOMMENDED
Truncation, or Field
Hard
to
predict
Never hurts
variants
limiting.
what you might to seek help.
Look for a Gateway find.
Page (Subject
Guide).
Confused?
NOT
Try an
Need more
RECOMMENDED encyclopedia in a
information?
Virtual Library.
Ask at a library
reference desk.
LUCK
Always
on your
side.
Keep
your
mind
open.
Learn
as you
search.
Step #3. Learn as you go & VARY your approach with what you learn.
Don't assume you know what you want to find. Look at search results and see what you might use
in addition to what you've thought of.
Step #4. Don't bog down in any strategy that doesn't work.
Switch from search engines to directories and back. Find specialized directories on your topic.
Think about possible databases and look for them.
Step #5. Return to previous strategies better informed.
Search Strategies We Do NOT Recommend
Because of their inefficiency and often haphazard and frustrating results, we do not recommend
either of the following two approaches to finding Web documents:
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Unit – The Internet and Networks
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
Browsing searchable directories. If you can find a search box, search a directory.
BROWSING is a sometimes fun rarely as efficient. The term "directories" refers here to any
collection of web resources organized into subject categories or some other breakdown
appropriate to the content (Subject Directories or directories of specialized databases or of
gateway pages). Browsing locates documents by your trying to match your topic in first the
top, broadest layer of a subject hierarchy, then by choosing narrower sub-subjectcategories in the hierarchy that you hope will lead to your target. Browsing encounters the
difficulty of guessing under which subject category your topic is classified. The taxonomy in
every directory differs, making browsing inconsistent from one search tool to another. The
category "health" may contain documents on medicine, homeopathy, psychiatry, and fitness
in one directory. In another "medicine" may include health, mental health, and alternative
medicine, but not the term psychiatry and may classify fitness only under "lifestyle."
Searching (typing keywords in a search box) retrieves occurrences of your words no matter
where they may be classified by subject. Use broad terms in searching any directory.
Following links to sites recommended by heavy use or commercial interest. Often
in search engine results, you will see links to sites that are selected based on how often
they are visited by others, or based on fees paid to the browser. Or you may see
recommended "cool" sites. Use these with caution! Others may visit sites for reasons
having no relation to your information interests, and the best sites for you may still be
largely undiscovered by the vast public searching the Web. Taste varies and should vary.
Make your own evaluations.

Table Matching Your Search Needs with the Features Search
Engines Offer
The purpose of thinking about your topic before you start searching is to determine what terms
to search for and what features you need to search successfully. The table below lists on the
left features of many search inquiries. Use it to determine which features your searches need. On
the left, the table describes search tool features designed to support each of the search needs
listed on the left.
The links take you to the table of search engines -- so you can pick a search engine with the
features you need.
Matching Search Tools Features worth
learning and using
Features of your search inquiry
PHRASE SEARCHING is a feature you
Are you looking for a proper name or a distinct want in every search tools you choose.
phrase ?
Requires your terms all to appear
in exactly the order you enter
 The name of an organization or society or
them.
movement
Enclose the phrase in double
 A proper name or an individual
quotations " "
 A distinctive string of words generally
Examples:
associated with your topic
"affirmative action"
"world health organization"
"a person's name"
Can you think of an organization, proper name, or
phrase to search for? It might help zoom in on the In , capitalizing initial letters will cause the
terms to be searched as a phrase:
pages you want.
World Health Organization
Are some of your terms common words with
many meanings and contexts ?

Children in conjunction with television and
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BOOLEAN AND will help:
children AND television AND
violence
journalism AND ethics AND
Unit – The Internet and Networks
BTT

also violence
Censorship as an aspect of ethics in
journalism
censorship
Google and AllTheWeband most other
search engines put AND in between words
automatically (by default):
children television violence
journalism ethics censorship
Do you anticipate lots of search results with
terms you do not want ?

BOOLEAN AND NOT will help:
"biomedical engineering" AND
cancer AND NOT "Department
Your search for biomedical engineering and
of" AND NOT "School of"
cancer brings you lots of academic
or its -EXCLUDES near equivalent:
programs, and you want research reports.
"biomedical engineering"
So you try to exclude documents containing
cancer -"Department of" Department of or School of
"School of"
BOOLEAN OR will help:
(women OR females) AND
networking
(Sarajevo OR Sarayevo) AND
peace
Are there synonyms, spelling variations, or
(literature OR litterature) AND
foreign spellings for some of your terms?
(French or francaise)
In Google, capitalize OR (no need to type
"and"):
 women, females with networking
peace sarajevo OR sarayevo
 Sarajevo, Sarayevo with peace
literature OR litterature french
 literature, litterature with French, francaise
OR francaise
In AllTheWeb, use parentheses and omit the
OR:
peace (sarajevo sarayevo)
(literature litterature) (french
francaise)
Are you looking for home pages and/or other
documents primarily about your term(s)?


The home page of the American Dietetic
Association
Pages primarily about Affirmative Action
Are you looking for terms with many possible
endings ?


Feminism, feminist, feminine
Children, child
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LIMIT TO TITLE FIELD IN DOCUMENTS
title:"American Dietetic
Association"
title:"affirmative action"
In Google, use allintitle:"affirmative
action"
TRUNCATION permits retrieving all these
variations in one search term (ONLY IN
ALTA VISTA):
femini* matches feminine,
feminist, feminism, etc.
child* retrieves child and
children
Some systems search word ending
variants automatically. See the specific
instructions for each of the recommended
search tools.
Unit – The Internet and Networks
BTT
E.
Computer Networks
Notes Computer Network
1. Access to Information
By networking computers, information can be transmitted directly from one computer to
another. Networking allows many people to share files and software in several ways.
o All users on a network can access software from one central location.
o All users on a network can access shared files
2. Access to Equipment
Computers to a network can share hardware making it more practical and cost effective.
For example, networks in this class allow you to share
o A printer
o An Internet connection
3. Types of Network

A local area network (LAN) consists of a group of networked computers that are
located in one building. For example, the computers in this school are networked
together and therefore it is a LAN.

A wide area network (WAN) is a group of networked computers located in a variety of
locations in a large geographic area. For example, the computers in this school are
connected to computers in the school board. Other school’s computers are also
connected to the school board network. Together these constitute a WAN. The
Internet is also a WAN.
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Unit – The Internet and Networks
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SCHOOL BOARD
SERVER
(WAN)
Other
Schools
LAN
JMSS
LAN
Classrooms
Comp Labs
INTERNET
Classrooms
Comp Labs
Library
Library
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Unit – The Internet and Networks
A Client/Server Network
The
SERVER is a
powerful
computer
that handles
all the
networks
shared
resources
The HUB is
the central
device where
all the nodes
and
peripherals
connect so
they can
communicate
with one
another
Each client computer
(or node) is
connected by a cable.
Each computer also
contains a Network
Interface Card (NIC)
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F.
Computer viruses and security issues
Notes – Computer Viruses
Computer viruses are programs that insert themselves into program files and boot
sectors (the boot sector is the area of the disk that contains the programs needed to
start and operate your computer). Viruses are activated when you run an infected
program. They immediately start copying themselves by looking for new files and boot
sectors to infect.
Just like an illness, viruses vary in how sick they will make your computer. Some are
harmless; others are just a nuisance such as causing a message to appear on your screen,
while others may destroy your hard drive and even your computers motherboard bios.
The most common ways that viruses can get into your system are
o Exchange of portable media storage devices (ie. CD’s, flash/USB memory)
o Internet and e-mail
o LAN
o Mischievous people who might have access to your computer
Computer Security
Computers help us keep in touch with others and share information by allowing the
outside world into our homes and offices.
This is good as long as we know who we are talking to and sharing information. However,
some bad people may use the opportunity for illegal or inappropriate purpose.
To ensue that information remains private and to avoid being the victim of cyber crime
you should:
Choose a password that is easy for you to remember but not easy for someone else to
guess. Combination of letters, numbers, and special characters
Do not share your password with anyone
Change your password regularly
Do not transmit confidential information over the Internet unless it is necessary. If you
must do so, make sure your browser or program is using data encryption.
If you are connected on the Internet for long periods or using high-speed connections,
then a firewall (hardware and/or software) should be used
Do not store confidential files on shared computers
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Unit – The Internet and Networks
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When you have visitors, turn off the monitor to discourage casual snooping. Similarly, in
the office try to avoid placing your computer where it is in view of others.
When you buy new equipment, do not place the packaging outside in the curb where
everyone can see. This is a possibly invitation for thieve.
G.
Ethics and the Computer
Personal Ethics
Ethics is the moral principles which determine the rightness or wrongness of a particular
act or activities.
Ethical has to do with choosing a right action over a wrong action.
Unethical has to do with intentionally acting in a bad or wrong way.
Business World and Ethics
Businesses are made up of people who all have different backgrounds and different moral
beliefs (values).
Today, most Canadians believe that people in business have a “social responsibility” – that
is in the best interest of society and the company.
Many individuals besides owners and shareholders have a stake in what businesses do –
employees, customers, special interests groups (ex. Greenpeace), the community, etc.
These stakeholders watch to see that business uphold their social responsibilities.
Examples include:
o Selling products that do not harm people or the environment
o Conducting business in a way that has a positive impact, for example,
conserving electrical energy during the recent hydro crisis
o Treating employees in a fair manner
o Not engaging in fraudulent or deceptive practices
H
Unit Test
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