FUNDAMENTALS OF ELECTRONIC
MAIL:
Q) WRITE ABOUT E-MAIL
ADVANTAGES AND THE DISADVANTAGES
ANS: E-mail (Electronic
Mail): E-mail is one of the most popular services available
through the Internet. E-mail is a
lot less expensive than a phone call and nearly as fast. Today many people all
over the world have been exposed to e-mail.
Through
e-mail system people can now receive and send e-mail to:
1. Nearly
any country in the world.
2. One
of millions of computer users.
3. Many
users at once.
Advantages of E-mail:
1. Convenience: There
are no trips
to
|
the post office,
and
|
no
need to search
for
|
|
stationary
|
and stamps.
Sending a memo
|
or short note it easy.
|
A message can be informal
|
or formal.
|
|||
2. Speed: E-mail is fast, based on the
speed of the underlying communication network.
3. Inexpensive: Once you are on
online, the cost of sending a message is small. Sending 100 pages document requires no more efforts or cost than sending a
one-page document.
4. Printable: A hard copy is easy
to obtain. However, since a great deal of correspondence does not need to be printed, using e-mail saves on natural
resources. You can keep an electronic copy of a message for your own records.
5. Reliable: Although messages are
occasionally lost, this is rare. Many mail systems will notify the sender if an e-mail message was undeliverable.
6. Global: Ever
increasingly, people and businesses all over the world are using e-mail.
7. Generality: E-mail is not limited
to text; it allows the transfer of graphics, programs, and even sounds.
Disadvantages of E-mail:
1.
Misdirection:
With e-mail, you are your own worst enemy. It is far more likely that you will accidentally send e-mail
to an unintended recipient than it is for someone actually to intercept your
e-mail.
2. Interception: It
is possible, although unlikely, that eavesdroppers are “listening in” on e-mail correspondence. As a rule of thumb, never
send an e-mail message that you would not want the whole world to see. It is
simple for someone to pass on your message, called e-mail forwarding another party.
3. Forgery: E-mail does not
preclude forgeries that is, someone impersonating the sender, since the sender is usually not authenticated in any way.
4.
Overload:
E-mail can also be too convenient and result in a flood of mail.
5.
No
response: A mild irritation sometimes associated with using
e-mail is dealing with recipients
who do not read and respond to their e-mail on a regular basis.
On the whole, the advantages of e-mail are
great, and the disadvantages, although real,
are
acceptable when compared with alternatives.
Q) WRITE A SHORT NOTE ON
A)USER-IDS B) PASSWORDS AND C)E-MAIL ADDRESS
ANS: A) USER-ID’S: Synonyms
for userid are user name and account name. Userid is merely the concatenation of the word “user“and
the abbreviation “id,” standing for identification. Your userid identifies you
to the computer. Userid’s have some mnemonic meaning. Userid’s are much easier
to remember. If you have a choice, pick as descriptive a name as possible, but
one that is also easy to type and associate with you. If you have a common name
or are part of a
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large organization, your first name and last name combined will
probably not uniquely identify you. In such cases, it may be necessary to
append a number to your name.
For example: Shaikayaan18.
B)PASSWORDS: Your password is a secret code that authenticates you to the computer.
This is done simply to check that
you are who you say you are. In theory your are the only one who knows the
password to your computer account and no one except you should be able to log
in to your account.
A good password should:
·
Be at least eight characters long.
·
Contain a no alphabetical symbol such as &,
%, or !
·
Contain a number.
·
Possess uppercase and lowercase letters.
c) E-Mail Addresses: The basic form of an e-mail
address is
username@hostname.subdomain.domain
There are some
exceptions, but this format covers most common addresses. The text before the @
(pronounced “at”) sign specifies the username of the individual, while the text
after
the @ sign
indicates how the
computer system can
locate that individual’s mailbox.
|
For
|
|
example:
|
||
The
|
first important point
to be aware of is
that the suffix
following the @
sign
|
gets
|
more general form left to right. That is, cs is a subdomain of colorado, colorado
is a subdomain of edu, and edu specifies a top-level domain name.
In this case, National is a master science major at the University of colorado.
Some of the examples of e-mail
id’s (addresses):
Ex: Imahaboobwithu@gmail.com,
rcrk78@rediffmail.com,reena007@yahoo.co.in
The number of periods
(a period is pronounced as “dot”) varies from e-mail address to e-mail address.
Most addresses have either one or two dots.
A given field in an e-mail address, that is, a
|
part
|
separated by dots, can be no more
|
|
than 63 characters long. All fields combined must total
|
less
|
than 256 characters.
|
|
Q) Discuss about E-mail Message Components
|
|||
In most e-mail
clients, before you see the message, you see a list of the messages showing:
·
Date
·
Sender name
·
Size (bytes)
·
Subject line (usually truncated).
Sometimes, additional symbols are used to flag whether or not you
have already viewed the message.
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A Sample E-Mail Message: -
From: Imahaboobwithu@gmail.com Wed June 18 11.00
EDT 2014
Header Date: Wed 18 Jun 2014 11.00.46
-0400(EDT)
To: ramakrc@rediff.com
Subject: bean
dip
Cc: sai_ms@yahoo.com
Greeting
|
Hi Guys,
|
Text
|
someone accidentally finished off the black bean dip last night.
Can of you
|
|
Pick up another case of it on your way home? I think Luke is on
bike today
|
||
so You might have to talk.
|
||
--mahaboob
|
||
**********************************************************************
|
||
mahaboob shaik
|
| office:(401)437-2134
|
|
332 Toast Lane
|
messages:(401)437-0012
|
|
Signature
|
East Providence.
|
| fax :(401) 437-2137
|
Rhode Island 02915
|
| Imahaboobwithu@gmail.com
|
|
**********************************************************************
The first five lines of the message are
referred to as the e-mail header.
Each mail client will display slightly different header information. The full
header includes some additional information, such as parts of the route the
message took to reach your computer and the unique message id associated with
this particular message. The From
field indicates you who sent the message and when. The Date field repeats the date and includes an interesting feature.
The To field specifies to whom the
message was sent. The subject field
provides a hint as to what the message is about.
The Cc field tells us that the message was
“carbon copied” to another user. Long ago when a
duplicate
message needed to
|
be sent, carbon paper was used to generate the extra
|
copy, hence
|
the term carbon
copy for a
|
duplicate message.
One field that
does not appear
that is worth
|
|
mentioning is Bcc, which
stands for blind
carbon copy. Additional
copies of the
|
message may
|
|
have been sent out. If the Bcc feature was used, we would
not see it in the heading.
|
||
Bcc is
used when you do not want one or more of the recipients to know that someone
else was copied on the message. The
opening “Hi Guys” is called the greeting
of the message. More formal messages are addressed like off-line letters and
usually begin with Dear. The main
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content is called the text
of the message. The final part of the message is known as the signature.
In many business situations involving frequent
message exchanges, it is standard to omit the greeting and signature
altogether. The greeting, text, and signature form the body of the message. Most e-mail clients recognize the header and
body divisions of e-mail messages.
Q) Discuss
ON E-mail Message Composition:
E-mail Message Composition:
The manner in which you compose an e-mail
message may vary from one mail program to another.
1. Structure: If
you are composing an e-mail message within a mailer, it will “prompt” you for certain information. Let us begin
our discussion from the point at which you have selected the “compose” button or command. The mailer’s
first field is generally the To
field. Here you should enter the e-mail address of the person to whom you are
sending the message. Rather than going to the Cc field to enter other e-mail addresses, many mailers allow you to
enter a list of names, separated by commas, on this line. This is one way to
make everyone feel equally important. For example,
To: ravikiran@hotmail.com, khaja999@rediffmail.com,
sai_ms@yahoo.com
You can specify a file to be attached to this
message in the optional Attachment
field. Then you will be prompted to enter a short description of your message,
called the Subject. This is your
opportunity to grab the attention of your recipient. If the subject line is empty, uninteresting,
or the addressee may not bother reading your e-mail right away, or even at all.
It should be concise and descriptive. The subject
along with your e-mail address is
usually the only information displayed when the recipient checks their mailbox
and decides what to look at.
To:
Subject: Network
Cc:
Bcc:
Attachment
|
Send
|
||||
2.Netiquette:
When writing your e-mail message, you should follow the rules of
informal letter composition. For
example
Dear Professor Jones, is
clearly very different than Hey Jones,
If the person you are writing to is a close
friend, you would naturally be less formal than if you are mailing your resume
to a prospective employer. The overall tone of the message body is also very
important.
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Informal rules of network etiquette or netiquette, suggest
practicing restraint when using e-mail to express opinions or ideas, especially
when the message will be read by people who do not know you well. When the
message is informal, a common practice is to use a smiley :-) or a wink ;-) to
indicate something said in joke. These little symbols and others like them are
called emoticons and resemble little
sideways faces.
Typing a message in capital letters is considered “shouting” and
doing so signals that
the sender is either an e-mail novice, very angry, excited, or
ignorant of the rules of netiquette. Not following the rules of netiquette may
result in a flaming by someone who took offense to what you said. A flame is a
nasty response from the offended party. Flaming often happens on mailing lists
when one user does not show consideration for others on the list.
3.Composition: For
sending e-mail to friends or people you know, simply type in a message, as you would say it. For people you do
not know or with whom you have little conversation be slightly more formal and
proof read your message. When applying for jobs or communicating with people
for the first time, proof read and spell check your message. Many mail
applications have a built in spell checker.
Q) EXPLAIN MAILER FEATURES
Mailer Features:
Most mailers provide functionality for
manipulating your mailbox contents, composing messages, and saving messages to
disk. For example, many mail applications allow easy access to directories or
folders to organize your e-mail according to sender, subject and so on.
A
typical mailer opened in a window will contain a series of buttons (or menu
items) with names such as Compose, Copy, Edit, File, Forward, Move, Next,
Reply, View, and so on.
1.Compose: A
Compose button typically provides the following features.
*
|
New
|
:
|
Compose a message from scratch.
|
*
|
Reply
|
:
|
Reply to the current message.
|
*
|
Forward
|
:
|
Pass the message on.
|
*
|
Vacation
|
:
|
You are going away and want automatic
response to be
|
generated, and have e-mail saved
|
2.File: A
File button often has the following functionality.
*
|
Save
|
:
|
Save
|
the
|
current
|
message into a file on disk.
|
||
*
|
Insert
|
:
|
Include a file in
|
the body of the message being composed.
|
||||
*
|
Open
|
:
|
Open
|
a
|
file from
|
disk
|
||
*
|
Attach
|
:
|
Append
|
a file to
|
a
|
message.
|
||
3.Reply: A Reply button usually
consists of the following items.
*
To Sender.
*
To all.
*
Forward.
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*
Include.
*
Include bracketed.
4.Forwarding:
You may have more than one e-mail address. It
is usually possible by forwarding all your e-e-mail from one account to the
other or, in general, directing a number of e-mail addresses to one. You can
specify the e-mail address to which you would like the mail to be forwarded.
Q) Explain the inner working
of e-Mail {or} Explain the store and forwarded system of e-Mail
1 E-Mail Inner Working:
Three main components (mailer, mail server, and
mailbox) are necessary for the e-mail system to work. .
Mailers:
A mailer is also called a mail program, mail
application, or mail client. A mailer is the software that allows you to
manage, read, and compose e-mail.
Mail servers:
The mail server
is a computer
whose function is
to receive, store
and deliver e-mail.
Conceptually, the mail server is always “listening” for the
arrival of new e-mail. If new e-mail has arrived for you, the server keeps
track of it.
Mailboxes:
An electronic mailbox is a disk file specially
formatted to hold e-mail messages and information about them. A system
administrator generally creates your mailbox for you. Your mailbox is uniquely
identified by your account name. Think of an electronic mailbox as the system
that serves the same purpose as a mailbox in the physical setting. The mailbox
is private and only the “owner” can read from it, while everyone else can only
send e-mail to it. Note that there may be a space limitation on the size of your
mailbox. At present Yahoo Mail service providing up to 1 GB of
space to their user mailboxes. Generally, once this limit is reached, new incoming messages are refused until you free up
space by deleting some messages.
2. Store and Forward
Features: It is common for PC users to have their inboxes. The inbox is same as the mailbox. Inbox indicates where new e-mail is stored.
When e-mail arrives, it is saved for the addressee in their inbox until they
“pick it up” by downloading the messages.
The
save and pick-up processes comprise the store-and-forward function.
Let us suppose that “Ramu” is sending an e-mail
message to “Krishna”. The message is routed via the “Simple Mail Transfer
Protocol” (SMTP) to Krishna’s mail server. Once the message arrives, the mail
server stores it o disk in an area designed for Krishna. The disk storage area
on a mail server is often called the mail
spool, which is called store.
Let us suppose that Krishna is running his
mailer. In this case, there is a new message from Ramu. His e-mail is forwarded
over the network to Krishna’s PC. This is called forward. The message is stored on Krishna’s inbox. Krishna’s mailer
will notify him that he has new e-mail
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UNIT-I
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Mail
|
||||
Incoming
|
Server
|
|||
SMTP
|
||||
Mail spool
|
||||
from
|
||||
Network
|
srinivas
|
|||
PC
|
Out going
|
POP
|
||
Network
Q) DISCUSS ON E-MAIL
MANAGEMENT
E-mail is a complex
communication mechanism with many uses. Here we share a few tips that may be
helpful to you. Clearly, you will develop your own e-mail style, but you should
not just let it evolve without thought. It is worth spending some time
evaluating how you use e-mail and how effective your responses are.
A new e-mail arrival is
usually signaled to you by your mailer. If you are already logged on, there may
be a beep, which can usually be suppressed if you find it annoying, or perhaps
something like an icon of a mailbox with a flag up. If you are just logging on,
a note may be printed on the screen that says you have new mail.
When you decide to view your
e-mail, your mailer will provide some sort of index of messages, with the
subject line displayed. Usually, the messages are numbered in sequence. They might
be displayed in either chronological or reverse chronological order. The mailer
typically displays the first or current message.
Action Options
If you do not receive a lot
of e-mail (say, less than twenty messages per day), it may be tempting to let them
“lie around” in your mailbox. However, if the volume of e-mail you receive
picks up, either because you find that you really like this method of
communicating or because you subscribe to one or more mailing lists, you will
need another strategy for dealing with you e-mail.
One recommended strategy, called triage, can be summed up as
follows:
1. Skim
for the most important messages (from your best friend, boss, and so on).
2. Skim
for what you can delete unread.
3. Then
work through the remainder.
Another possible strategy, called skim and delete, works as
follows:
1. Skim
through your mailbox, reading only those messages that are important to you
while deleting the rest.
2. If
possible, deal with each message immediately and generate a response, if
necessary.
7 | P a g e
3. If the message requires more than a couple
of minutes to address, save it for later, if time does not permit handling it
now.
If a message is very
important, you should save it. Messages can be stored in folders organized by
subject, date, and so on, or they can be saved in your mailbox.
Naturally, the mileage you get from such
strategies will vary. However, it is critical to develop some sort of protocol
for dealing with e-mail, especially if you find it becoming a burden.
Vacation Programs:
|
||||
If
you receive a
lot
|
of
e-mail, you may
consider the
|
possibility of
|
configuring
|
a
|
vacation
program when you
go
|
away for
an extended period
of time. A
vacation program is
one
|
|||
that
automatically replies to
|
your
e-mail. Usually, the
program
|
sends
a brief
|
reply back
|
to
|
each message you receive. For business purposes, it is customary
to include to name and telephone number/e-mail address of someone to contact in
your absence. You should be aware that a large number of users despise vacation
programs.
Not all vacation programs are created equal.
With a good one and the right mailing list server software, things can work
very well. Nevertheless, at least think about the points mentioned here before
installing such a program.
E-Mail and Business
When working in a business environment that
uses e-mail, you should be aware that it is currently legal for an employer to
read all company e-mail. Very few companies actually do read employees’ e-mail,
but you should be aware that they can. A company could maintain backups of all
e-mail for a long period of time. If necessary they could go back and review
the e-mail messages of an employee. Such backups can also be subpoenaed.
Businesses sometimes use e-mail filters. The
filters can work in both directions, to limit either incoming or outgoing
e-mail. The filtering mechanism examines each messages e-mail address before
deciding whether or not to send the mail on. Business use e-mail filters to
restrict with whom their employees can communicate.
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T H
E I N T E R N E T
Q) WHAT IS INTERNET AND
EXPLAIN THE HISTORY OF INTERNET
The Internet is a global network of networks
connecting millions of users worldwide via many computer networks using a
simple standard common addressing system and communications protocol called
TCP/IP (Transmission Control Protocol/Internet Protocol). This includes federal
networks, regional networks, educational and some foreign networks. The
connection between the different networks is called "gateways". These
gateways serve to transfer electronic data worldwide.
The primary use of the Internet is electronic
mail (commonly called "e-mail"). Millions of people use the Internet
for electronic mail capabilities. Electronic mail however, is only a small part
of what the Internet offers. There's also
·
Chat groups
·
The World Wide Web
·
e-mail and mailing lists
·
Bulletin boards and newsgroups
·
Remote computer access (telnet)
·
File transfer (using ftp, or file transfer
protocol)
HISTORY:
In 1969 Blot, Beranek and Newman, Inc., (BBN)
designed a network called the Advanced Projects Agency Network (ARPANET) for the United States
Department of Defense. Initially only four nodes (hosts) comprised the ARPANET.
It enables researchers to share “super-computing” power. The ARPANET later
became known as the Internet.
The use of local area network (LAN) became more
prevalent during the 1970’s. In later years, this concept had a tremendous
impact on the growth of the ARPANET.
By 1972, the ARPANET was international. The
number of nodes on the network was up to 23, and the trend would be for that
number to double every year from then on. Ray
Tomlinson, who worked at BBN, invented e-mail.
In 1979 User Network
(USENET) was started. Newsgroups emerged from this early development.
In 1980 Transmission Control Protocol /
Internet Protocol (TCP/IP), a set of
rules governing how networks communicate, was established. The Internet grow
beyond being largely research oriented to including business applications and
supporting a wide range of users. As the Internet became larger, the Domain
Name System (DNS) was developed, to allow the network to expand more easily by
assigning names to host computers in a distributed fashion.
In 1983 the United States Defense
Communications Agency required that TCP/IP be used for all ARPANET hosts. Since
TCP/IP was distributed at no charge, the Internet became what is called an Open
System. This allowed the Internet to grow quickly, as all connected computers
were now “Speaking the same language.”
During the 1990’s, a lot of commercial
organizations started getting on-line.
This stimulated the growth of the Internet like never before. URL’s appeared in
television advertisements and, for the first time, young children went on-line
in significant numbers.
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UNIT-I
|
|
Graphical browsing tools
were developed, and the programming language HTML allowed users
|
|
all over the world to publish on what was called
|
the World Wide Web.
Millions of people went
|
on-line to work,
shop, bank, and be
entertained. The Internet played
a much more
significant
role in
|
society,
as many non-technical users
from all walks
of life got
involved with
|
|
computers.
Computer
|
literacy and Internet courses sprang up all over the country.
|
|
In
|
1991 Gopher was developed. It is a Menu based
Application, allows you to “go for” or
|
|
search
files on the
|
Internet.
|
|
In 1991 Tim Berners-Lee created World Wide Web (WWW). It is a simple way to publish information and make it
available on the Internet.
In 1994 Netscape Navigator released by Netscape Communications Company. It
is a Web browser through which users can view the web pages.
In 1994 Stanford graduate
students David Filo and Jerry Yang developed their Internet search engine
called Yahoo!., which is now
world-famous.
In 1995 the Internet
programming environment, Java, was released by Sun Microsystems, Inc. This
language allowed programmers to develop Web pages that were more interactive.
The Internet is still
growing at a rate of 100 percent each year. The number of computers linked to
the Internet is now 16 million and increasing. There were a number of key
reasons for the Internet’s Great Success. We can assume that the Internet will
continue to grow, change, and support new applications.
YEAR
|
TYPE OF INTERNET USED
|
||
1969
|
APRAANET
|
||
1971-1973
|
23 NODES
|
||
1975-1977
|
UUCP
|
||
USENE
|
|||
1979
|
|||
CSNET
|
|||
1981
|
BITNET
|
||
1983
|
TCP/IP
|
||
1985
|
NSFNET
|
||
1987
|
Morris Worm;IRC
|
||
1989
|
NSF
|
||
1991
|
WWW:Gopher
|
||
Mosaic
|
|||
1993
|
Netscape Communications
|
||
Yahoo
|
|||
1995
|
Java;Microsoft discovers Internet
|
||
1997-1999
|
Netscape releases browser source code
|
||
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Q) EXPLAIN HOW THE INTERNET WORKS
1. Interconnected Networks and
Communication:
The Internet is essentially a network of networks, and its success depends upon
“cooperation.” Since no one person, organization, or government is responsible for the
Internet, cooperation among the networks and computers that
compose the Internet is paramount. This cooperation is accomplished by a common
set of protocols. The protocol that
determines how computers connect,
send, and receive information on the Internet is Transmission Control
Protocol/Internet Protocol (TCP/IP).
In fact, TCP/IP consists of about 100 different protocols, and new ones are developed and added regularly.
The TCP/IP has been described as the “language
of the Internet.” In the same way that a common language allows people of
diverse backgrounds to communicate, TCP/IP allows many different kinds of
computers, from personal computers to mainframes, to exchange information. The
two main protocols in the TCP/IP suite are TCP and IP. TCP permits
communication between the various computers on the Internet, while IP specifies
how data is routed from computer to computer.
Ø How TCP/IP Works:
To illustrate TCP/IP working, consider sending
an e-mail message or requesting a Web page. In either case, the information is “formatted
according to its specific application protocol.
The TCP/IP , the information to be sent is
split into IP packets, called packets for short, and transmitted over
the Internet.
Each
packet of data contains the following information along with data.
v Address
of the sending computer.(Source computer)
v Address
of the receiving computer. (Destination computer)
v Sequence
number indicating where the packet fits in the original message.
v Error
checking information to ensure that the packet is not corrupted while in
transit.
The packets are reassembled after being received at the
destination computer. A message is sent from the destination computer to the
sending computer to resend any missing or corrupted packets. Suppose that a
packet does get corrupted, the destination computer must send a message
requesting that the packet be resent. After receiving the message successfully,
the destination computer responds, either by delivering the e-mail message to
the recipient’s mailbox or by servicing the request for a web page, as required
1
|
2
|
||
Network
|
2
|
4
|
|
3
|
4
|
||
Packets
|
|||
Source Computer
|
Destination
Computer
|
||
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|
|||
2. Physical Components:
The Internet includes a host of physical
components; these components include such items as servers, routers, and the networks themselves. Servers are
computers that answer requests for services, such as list servers, mail servers, and news servers.
A router
is a special-purpose computer that directs data packets along the network.
Routers can detect whether part of the network is down or congested and can
then reroute traffic. Think of a router as a highly efficient and well
functioning traffic police.
Networks provide the
physical means to transport packets of information.The following mediums are
employed:
·
Copper
wires, which transmit messages as electrical impulses.
·
Fiber-optic
cables, which use light waves to transmit messages.
·
Radio
waves, microwaves, infrared light, and visible light, which
all carry messages through air.
3. Network Connections:
To connect to the Internet from home generally
uses a modem and a regular telephone line to connect to an Internet Service Provider (ISP). A second modem at the ISP’s end completes the connection, and
the slower of the two modem speeds determines the maximum connection speed,
usually 28.8 kilobits per second (Kbps). The modem is needed to convert from
analog to digital and back again.
A
business, organization, or school network typically uses network interface
cards instead of modems to connect the personal computers that are part of
their LAN. These connections are usually leased from the telephone company.
Another option is an Integrated Services Digital Network (ISDN), which is slightly more
expensive, but uses regular telephone lines and replaces modems with special
adaptors up to five times faster than a traditional modem.
4. IP Addresses:
Each computer and router on the Internet must
have a name so that it can be uniquely identified. The domain name provides a
convenient people-oriented computer-naming framework that uses symbolic names.
Domain names are easy-to-remember symbolic strings. For example: Rudolph@northpole.org.
IP addresses are numerical names that uniquely
identify each computer on the Internet. An IP address consists of 32 bits, or
four bytes. One byte can represent a number from 0-255. Each of the four bytes
of an IP address can represent a natural number from 0-255. It is common to
express IP addresses as four natural numbers separated by dots. For example
132.177.4.124 Each IP address consists of a network component and a host
component.
IP addresses play a vital role in the routing
of packets over the Internet. Source and destination IP addresses are included
in each packet. The addresses provide directions on where the packet should go.
a) Customary way of IP Address
132.177.4.124
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b) systematic IP Address
Network host
32 bits
c) the
binary equivalent of the IP Address from (b)
10000100
|
10101010
|
00000100
|
01111100
|
Q) Discuss about internet
congestion and how to overcome it.
Internet Congestion
As
the internet becomes increasingly heterogeneous the issue of congestion control
becomes more important. Internet handles an enormous amount of traffic every
day at any given movement millions of users are sending messages or browsing
the 80-million more pages of the World Wide Web.
The flow of data/traffic on the internet can suffer from
congestion on the number of points. Consider the (for example) retrieval of web
page from the US – White house internet site (http://whitehouse.gov) by a user
at SK University, India.
Possible points of congestion include
1. White
house’s server’s link/connections speed
2. The
India/US link (National backbone) that the data travels over
3. The
regional network (with in India) which delivers the traffic to the SK.
University
4. The
SK University own connection speed to the internet
5. The
Band width available in the SK University local area network etc.,
Any or all of above may be the points with which user can suffer
from congestion as a result of the traffic being carried exceeding the capacity
of the connection.
Solutions
W3C (World Wide Web consortium) along with other researchers are
addressing the issue of network congestion. Some of the solutions are
1. Improving
the process of connecting to a web server
2. Introducing
new techniques to serve web page request
3. Refining
how a URL is resolve
4. Avoiding
unnecessary graphics and using “PNG” format over the “gif” format
5. Reduction
in the size of router tables by rearranging how blocks of addresses are
identified Along with above technological improvement w3c continuously working
to reduce Internet congestion created by the World Wide Web.
Q)Discuss about Internet
Culture
Internet Culture
An entire culture as sprung – up around the
internet. The Internet has emerged from being a research medium to one that
includes advertises, commerce, forums for exchanging ideas on a near infinite
set of subjects.
Since the internet is not-regulated any thing and every thing can
be found on the web that is the editorial control which is applied to
traditional print media is missing. So, distinguishing between inaccurate and
accurate information is a necessary part of the Internet culture. To, find
valuable information user need to be able to shift through web pages and
separate the useful from the useless.
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The lack of regulation that permits the proliferation of
information on the internet also facilitates the interchange of ideas i.e., any
one with an internet connection can express their views globally i.e., freedom
of expression is one part of the internet culture. Another aspect of Internet
culture is created by the communication channels. People from all over the
world are able to exchange ideas via e-mail, IRC/Internet relay chart), mailing
list, news groups, web pages, web logs (blogs) etc
The marketing techniques for advertising on a
web are also becoming more sophisticated. An industry is developing to monitor
who visits what sites. So, that ads can be targeted more specifically to
certain users.
So,
as a conclusion the Internet has had a enormous impact on society and its
influence will no doubt continue.
Describe briefly about Business Culture and the
the Internet.
Business culture and the Internet
Many
businesses are recognizing opportunities in on-line activities. In news papers
and magazines. We constantly see URL’s with which we can read (surf or browse)
them instantly. Another question that may users and companies pose is “Is it
safe to do business on the internet”. Some companies are prime to convenience
you that it is safe. Business on the web is till in its infancy and many
questions remain unanswered.
On-line business
The Internet functions nicely as a means of facilitating business
communications with in a given company as well as between companies. This is
also an excellent venue for advertising and conducting trade with consumers. In
addition to lowering transaction cost, the internet is transforming the market
place in to a
global environment. For companies, this means more potential
customers, for customers this means a greater selection of services and
products. This revolution is literally changing the way a lot of companies do
business so, few interesting business models on the internet. Marketing – web
presentations or web-casting to market through net
Partnership
– services and products can be deliver to a joint ventures
Advertising – consumers can be targeted for a
specific type of ads on the basis of their search requests
Retail – consumers can view select, order and pay for their
products on-line Service – consumers can use wanted service on-line and pay
accordingly
Software – users can use software and pay for
it on-line and also potential buyers can try a product before purchasing it.
Subscription
– subscribers can subscribe on-line for a newspaper or a magazine. They also
can view, the news paper on-line 24-hours a day, with which they can get most
currently news. Any no. of business models can be evolved using internet as a
tool or media.
Q) What is search engine?
Discuss
SEARCHING THE WORLD WIDE WEB
The rapid growth of the web as well as its huge size, peoples are
spending their time trying to find things on the web rather than actually
reading the material ‘web directories’ and ‘search engines’ are the tools which
allow you to find information more quickly and easily i.e., these two are the
basic approaches which are evolved in response to the need to organize and
locate.
A. Web directories or Directories
The first method of finding and organizing web
information is the directory approach. A web directory or “webguide” is a
hierarchical representation of hyperlinks. The top level of directory provides
a wide range of general topics
such as Arts, Education, Entertainment, News, Science, Sports and
so on. For each of these topics there may be hyperlinks which leads to more
specialized sub topics. They intern may have a number of sub-topics and so on,
until you reach a specific web page.
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It
is very
|
easy
|
to use and also you
|
need
|
to know exactly
|
what
|
for you are looking i.e., you can
|
|||
continue
to move down through
|
the hierarchy by selecting
|
sub-categories and
narrowing
|
the
|
||||||
search
at each level.
|
|||||||||
Directories
are useful if you
|
want to explore a
|
topic and
|
its
|
related areas. If you are
|
|||||
interested
|
in a very specific
|
topic
|
then
|
search
|
engine or
|
Metasearch engines are more
|
useful.
|
||
Popular directories – www. Yahoo.com www.hotmail.com
www.google.com www.aol.com www.infoseek.com
B. Search engines
This is second approach to organize and locate information on the
web. Search engine is a computer program that does
1. Allow
you to submit a query that consists of a word or phrase, which describes the
specific information.
2. It
searches in its database to try to match your query.
3. Returns
a list of clickable URLs, the list is usually ordered i.e., better matches
appears at the top.
4. It
also permits to revise and resubmit a query
The user-friendliness and power of query languages vary from
search engine to search engine. Once you learn to use a specific search engine
query language effectively. You can quickly search a very narrow topics.
The popular search engine are – www.google.com www.infoseek.com
www.webcrawler.com www.yahoo.com
www.alo.com www.altavista.com etc
C. Metasearch engines
These Metasearch engines are all-in-one search engines, which
performs a search by calling more than one search engine. The results are
without duplicate and also ranked according to match. The advantage of
Metasearch engine is that you can access no. of different search engines with a
single query. The disadvantage is that you need to spend more time evaluating
the results to decide which hyperlinks to follow. So, as a conclusion for very
specific topic, which is hard-to-locate Metasearch engine can often be a good
starting point.
Popular
Metasearch engines are
www.metasearch.com
www.metafind.com
www.metacrawler.com
etc
D. White pages White
pages provide you with an on-line mechanism for looking up information about individuals. These pages can be
use to track down telephone numbers, s-mail addresses and e-mail addresses.
Users can request that information about them be put in to a database. For a
given set of white pages. Many of the white pages are very comprehensive
listing information about people, who are not even listed in the telephone
book.
When you submit a request for information about a person some of
the white page services may make a record of your requests obviously people can
abuse white pages and some people feel that white pages are an invasion of
their privacy.
popular
white pages are
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www.whowhere.com
www.bigfoot.com
etc
Q) Explain about Search
Fundamentals and strategies
Search Fundamentals
Some
of the common search related terms are –
1. Search tool:- Mechanism for locating
information on the web.
2. Query: - Description of
information being sort.
3. Query syntax:- A set of rules to
form a legal query.
4. Hit: - A URL that a search
engine returns in response to a query.
5. Match: - A synonym for hit
6. Relevany score:- A
value that indicates how close a match a URL was to a query.
7. Pattern matching queries:-
The most basic type of query is a pattern matching query. User can formulate it using a key word or a
group of keywords. The search engine returns the URLs, which contains “these
keywords”.
The meaning of this phrase varies between
search engines. Some search engines perform a process called “stemming”, which
means they use variations on the endings of words in your query.
For
example, the search engine may try the plural form of words as well as the
singular or vice versa. The query with the quotes is the return URL contains
complete keywords. It also important to spell the keyword correctly because
misspelling a keyword might result in zero hits.
Boolean Queries
Boolean queries involves the Boolean operations (AND, OR, NOT) and
most search engines allow you to formulate Boolean queries. For example “paint”
and “house” or “Information” & “Technology” i.e., some search engines
allows you to do multiple “ands”. The exact syntax of a query will vary from
search engine to search engine. For example, some search engines use
“+” for AND, and nothing for “OR”, and – for NOT.
Search strategies
Determining which search engine to use can be challenging. But one
can try to find one based on the following
1. Possesses
User friendly interface.
2. Has
easy-to-understand, Comprehensive documentation.
3. Speed
(time required to process).
4. No.
of return hits.
5. Good
job in assigning relevance scores.
If you can find a search engine that meets most of these criteria,
you should can concentrate on learning it well.
Q) HOW DOES A SEARCH ENGINE
WORKS (COMPONENTS OF SEARCH ENGINE)
To describe how a search engine works, we split up its functions
into a number of following components.
1. User interface
The user interface must provide a mechanism by which a user can
submit queries to the search engine. Universally this is done using forms. In
addition the user interface should be friendly and visually appealing. Finally
the user interface needs to display the results of the search in a convenient
way along with the relevancy score. With this the user can make an informed
choice as to which hyperlinks to follow.
2. Searcher
This is a program that uses the search engines index and database to
see if any matches can be found for the query. User query must first be
transformed into a syntax that the searcher can
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process. More over a highly efficient search strategy must be
applied. Computer scientists have spent years developing efficient search and
sorting strategies.
3. Evaluator
The searcher component locates URLs that match your query (result
set) not all of the URLs will match your query equally well. So, the ranking
process is carried out by the “evaluator” ,a program that assigns a relevancy
score to
each URL in the result set.The relevancy score is an indication of
how well a given page matched your query.
The process of computing relevancy score varies from search engine
to search engine. A number of different factors are involved, and each one
contributes a different percentage towards the overall ranking of a page.
1. “How
many times” the search word appears in the page
2. Whether
the search words appears in the title/subtitle
3. The
proximity of the query words tothe beginning of the web page
4. Whether
the query words appear in the CONTENT attribute of the META tag.
5. How
many of the query words appear in the document.
The
algorithms used by evaluators are imperfect but they are getting better
day-by-day
4. Gatherer
Search engine obtains its information by using “gatherer” – a
program that traverses the web and collects information about web documents.
This program does not collect the information every time a query is made.
Rather, the
gatherer is run at regular intervals to incorporate URLs into the
search engine’s database. Alternate names for this program are bot, crawler,
robot, spider and worm.
A Gatherer may employ following two different methods to search
the web for new pages. In practice hybrids of these two procedures are often
used. These two techniques are well-known search strategies.
a) Breadth First Search (BFS)
Breadth Fist Search proceeds in levels “across” the pages. The
Gatherer begins at a particular point and explores all pages that it can reach
by using one hyperlink from the starting page. Once it has exhausted all web
pages at that one level, it explores all of the web pages that it can be
reached by one hyperlink from any page that was discovered at level one. This
process is repeated level-by-level until no web pages are found. Then the
gatherer may need to jump to a new starting point.
For example as illustrated in the above figure having found page
11, the Gatherer has exhausted the entire collection of web pages hyperlinked
to the starting point ‘A’. The gatherer than chooses a new starting point and
continues from there.
b) Depth First Search (DFS) method:
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A DFS proceeds by following a chain of hyperlinks “down” as per as
possible. The gatherer begins at a particular web page and explores one of its
hyperlinks at the new pages. The Gatherer follows another hyperlink and so on.
In contrast to the BFS hyperlinks on a given page are not fully exhausted
before the Gatherer goes to the next level page.
When the Gatherer reaches a page from which no new pages can be
discovered it back-tracks until it go forward again and discover new pages
i.e., the search goes as deep into the document collection as possible before
back-tracking.
As with when no more pages can be located often full back-tracking
DFS jumps to a new starting point. For example as explained in the above figure
have found 11th page DFS jumps to a new starting point.
5. Indexer
Once the Gatherer retrieves information about web pages the
information is put into a database and indexed. The indexer creates a set of
keys that organizes the data, so that high-speed electronic searches can be
conducted to locate and retrieve wanted information quickly.
THE World Wide Web: The World
Wide Web (WWW) or Web is a software application that makes it (internet) easy
and possible for any-one to publish
and browse hypertext documents on the internet. The web as encompassing all of
the information available through web browsers. The web has developed a huge
following because of its ease of use and visual appeal. It is called a “web”
because the interconnections between documents resemble a spider’s web. WWW is
the part of the internet that most users see and use and which has made it so popular..
The internet can be thought of “As a very large group of networked computers”
i.e., the web therefore uses the internet. In fact, the web is the driving
force behind the internet. The web runs on the HTTP protocol. Browsers are
multi-protocol, i.e., they can talk to many different kinds of resources that
make up the internet.
Technology has improved to such an extent that
the web is now considered to be indispensable for education, business and
entertainment. There are billion of pages on the web and millions more are
added every day. The following figure illustrates the relationship between the
internet and the no. of other applications. As indicated in the above figure,
each application uses the internet as a transport mechanism. A central idea in
the development of the web was “URL” which uniquely identifies a resource on
the web. This unique address make linking to any one web documents possible.
The non-linear nature of the web is one of its main attraction. The sheer
amount of information available on the web makes it the greatest collaborative
nongovernmental effort in the history of human-kind.
Web-browser details
Some of the interesting
features of web-browsers are bookmarks, plug-ins, and helpers. Most of the
browsers have a number of options that users
can set some of them are
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1. Cookies – user can ask to be notified before a cookie is written and user
can then decide whether or not to allow the cookie to be written.
2. Disk cache – we can set the size of cache, which stores the HTML source code
and images of web presentation you have visited.
Then, If you reload one of these pages, the browser can load the cached copy
and the page will appear very quickly.
3. Fonts – user can select a wanted font specification and also set default
font size.
4. Helper applications – user may configure helper applications
to handle contain types of data that the
browser is enable to
process. For example MS-word or PostScript files.
5. Home page location – user can specify the initial page that
gets loaded when the browser is first launched.
6. Images – users can specify whether or not images are loaded. Options for
colour selection are also available.
7. Scripting options – users can enable or (java or vb
scripts) disable these type of scripts from running within user browser.
8. Messages – user can specify a default signature file or a default carbon copy
(cc) address for outgoing messages. This can be set for regular email or for posts to newsgroups
Web-writing
Styles
Writing
style require for a web page is different than that of writing style for
printed page Readers usually spent less time at a web page than they do with
off-line page.Web-pages are typically very short where off-line material as
large in size and greater life.So, to design a web page, designers should have
presentation capabilities to grab the attention. We-pages are dynamic and also
often involve multi-media. In the case of off-line material, the quality of
writing holds the reader’s attention. The following are the few examples for
different web writing styles with different goals.
The
Biography
The web
page has some background and is covered with information. The page must contain
image of an author with numerous hyperlinks. The hyperlinks are displayed as a
group of images as well as clickable text Each image incorporates a short,
descriptive phrase explaining where the hyperlink leads. The use of multimedia
and choice of pages and their connections are user choice.
The
Business Exposition
The web page must catch the attention of the
user. The menu is located in an easy-to-use spot, and
very little must be read before a hyperlink
can be selected. The page must be compact, colorful, and easy to
explore. The writing style must be simple and
direct. The page has a descriptive title, an effective header, a
short footer, and a centrally placed,
well-designed menu.
The Guide
The page starts with a descriptive title. The
image map should appear at the top of every page. The
page should provide
convenient information about bands. The graphics are well done, the page is
easy to read,
and the hyperlinks are easy
to follow. The image map at the top of the screen and the search mechanism
allow
you to locate the
information quickly. The color scheme must be appealing. Notice the
alternating-color
horizontal
bars that separate the different sections. The presentation is coherent,
informative, and easy to use. It creates an uncluttered user-friendly environment.
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The Tutorial
The presentation packed with
information must be impressive. The text phrases are easy to read. The
select
menu allow the user to decide what topic to purse next. All the presentation
must be user-friendly. The writing must be short, descriptive, and light but
informative. The graphics spruce up the appearance of the page.
Web presentation outline, design and management
A web
presentation is a collection of associated hyperlinked web pages that have some
underlying theme or concept. The Key elements in an effective web presentation
are
1. Details:– A presentation that includes well-thought-out touches can make a
positive impression on the reader.
Good choices of background color, headers, footers and even appropriate size of
fonts are all important.
2. Coding:- A competent HTML
programmer uses the appropriate elements of style in the web page
3. Features:- A few “bells and whistles” can improve the feel of a set of
web-pages.For example
animated GIF, flash screens or applets
4. Graphics:- A modest use of in-line
images is probably one of the most significant way to enhance your design
5. Layout:- A poor layout will
discourage people from spending too much time on the presentation. So, web pages with convenient navigation
make more people to visit.
6. Writing quality:- Good
writing and an interesting style are also necessary for a solid presentation.
7. Load time:- Care should be taken not
to include two many graphics or any large graphics
8. Hyperlinks:- Navigation is a key
element to any good web presentation. If user can move around the pages easily, he will be more
impressed.
Goal
Setting
The important steps in producing a
high-caliber presentation are goal Setting, outlining, navigating,
designing,
coding and revising. The objective of goal setting is to decide on specific
parameters for your web presentation, to aid you in focussing your project.
Most people find it helpful to write down their goals. The written records
allow you to go back and see how successful you were at accomplishing your
goals. Each project will merit its own additional questions.
Outlining
Once the goal is set for the
web presentation it is a good idea to produce an outline. The subject
matter, combined with goals,
will dictate the way the material is most naturally portioned. Most users work.
best if they design their
outline in HTML, rather than just handwriting it on paper. Actually seeing the
outline
on-line seems to help users to decide what is
missing, who needs to be deleted, and what needs to be moved.
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Navigation tools
These tools provide
hyper-links that allow you to move more smoothly through your web pages.
Readers should be able to
jump to any other page directly according to their interest. The organization
of a web
presentation will dictate
the nature of its accompanying navigational aids. Some of general
organizational
arrangements are
a. Circular:-
This arrangement of web
pages supports forward and backward movements through web pages. As
illustrated in figure.
This
is good for describing step-by- step procedures or instructions.
Conceptually
the pure circular organization
is very
clear. One draw back in this approach is that there is no chance to jump to the
middle of the
presentation.
But to add a bit more complexity one can add hyper links to the first and last
page to jump in to
the
middle of the presentation.
b. Exploratory:-
This
arrangement allows jumping from nearly every page to nearly every other page.
The first thing you
need to
notice about these arrangements is that there are more hyperlinks. But this
arrangement gives the
reader
the freedom to move, as he desired, as illustrated in the figure.
Note that
image maps work well in the explanatory type of organization
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The
hierarchical arrangement permits a more limited number of hyperlinks from the
introductory page
and each
succeeding page leads to additional hyper links. This arrangement yields a tree
like directory
structure.
The fanout, defined as the maximum no. of hyperlinks available from any page
should be kept small
in this
arrangement. In general it should be no more than ten hyperlinks. The depth of
the web presentation
i.e.,
levels of the tree should be restricted to five at most.
This
model is well suited for describing organizations, institutes and companies,
which has inherent
hierarchy.
So, as a conclusion try to incorporate best navigation in your web presentation
depending on objective.
Designing
& coding
To write an effective web
presentation, the goal should be set and develop an outline and a global
navigational design. Producing an HTML document from a design involves coding,
as well as writing. There fore, it is necessary to develop a serious web
presentation. The writing and coding are both essential, and they should take
place in parallel. This is true whether an individual or a group is developing
the presentation.
Revising
Having
completed the first draft of the web presentation, fine-tuning is the crucial
step for converting an average presentation into a excellent one. The goal at
this point is to move forward with the remaining work of perfecting the
presentation.
Registering
Web pages
Registering
a web page means having the page indexed by a search engine or having other
prominent pages display hyperlinks to the page. The goal is to have the page
viewed by more user i.e., search engine indexes a page then it return the page
to user’s queries. Many search engines allow you to fill out and submit an
on-line form telling the search engine about your page. Search engine designers
want their programs to
know
about more web pages then any other search engine. In general the speed of the
search and the number of hits a search engine finds judge the performance of
search engine.
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Some search engines may
index your WebPages automatically, since they have techniques for “going
out and seeing” i.e.,
pro-active registration. People with commercial pages most commonly use this
service
The
Internet has experienced spectacular growth over the last few years. A wide
range of knowledge is needed by anyone interested in publishing on and
participating in the World Wide Web.
In other words, everyone should be Internet Literate.
The World Wide Web (WWW), or Web
for short, is a software application that makes it easy to
publish
and browse hypertext documents on the Internet. The Web has developed a huge
following because of its ease of use and visual appeal. It is called a “web”
because the interconnections between documents resemble a spider’s web.
The
Internet can be thought of as a very large heterogeneous group of networked
computers. The Information on the web is transported over the Internet. In
fact, the web is now the driving force behind the Internet and new Internet
technology is being developed to meet the needs and wishes of web users.
Overview
of www
The World
Wide Web (WWW) is a network of the computers all over the world. WWW is also
knows as the web is a client-server network. Communication on the web happens
through HTTP.
Web
information is stored in Web pages Web Pages are stored on Web servers
Web
clients view the pages in a Web browser. Popular browsers are Internet Explorer and
Netscape Navigator
Internet is a communication network linking
computers world wide.
The World
Wide Web is a way of accessing information over the medium of Internet. It is
an information sharing model that is built on top of the Internet. WWW is also
known as the web.
WWW
is not a single entity it is a client-server network that includes web servers
that are designed to deliver files to the client. The web uses the http
protocol to transmit data.
A web site is a collection
of files, linked together and saved on the web server. These files are known as
web
pages. Client utilizes browsers such as Internet
Explorer, Netscape Navigator etc to access web documents
called
web pages. First page which is displayed in the web browser when it connects to
the web site is called the home page.
BROWSING
& PUBLISHING
Browser
Bare Bones
A Web browser is one of many
software applications that function as the interface between a user and the
Internet. The browser not only sends messages to Web servers to retrieve wanted
page, but also parses
and renders the HTML code.
That is, the browser interprets the code and displays the page content in
browser window. Many browsers have built-in mail clients and/or newsreaders.
Additionally, auxiliary programs such as
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helper
applications and plug-ins can be configured into the browser. Browsers will
continue to grow in complexity and functionality in the foreseeable future.
Popular browsers – Microsoft’s Internet Explorer (IE), Netscape
Navigator, Mozilla Firefox etc.,
Below
figure illustrates the terminology associated with a browser window. The
different components of the window are numbered. A short explanation of each
part is
1. Title bar – Location where the title is
displayed
2. Menu bar – Headings of the main pull
down command menus
3. Tool bar – Number of single mouse click
commands
4. Location or Address bar – The area
where the URL is displayed
5. Hot buttons – Single click buttons to
provide no. of convenient features
6. Icon – Image which shows movement when
a document is being downloaded
7. Scroll Bar – Arrows which allows to display a different part of the page
8. Document area or browser window – Part of the window used to display the
contents of documents
9. Status bar – Area to display a programmer specified message
10. Inline Image – An image appearing with in a document
11. Hyper Link – A high lighted part of a document that, when selected, causes the
browser to retrieve and display a
new document
Note on
Hyperlinks and Coast-to-Coast Surfing
Hyperlinks are clickable
text and/or images that generally cause the downloading and rendering of a new
HTML document. Hyperlinks are often displayed in a different text color than
the remainder of the
document,
and they are usually underlined to make them stand out. An image serving as a
link may have a border around it that is the same color as other hyperlinks on
the page. Moving the mouse over a hyperlink will cause the mouse cursor to
change appearance, perhaps form an arrow to a hand . The location (URL) of the
link being moused over will
be displayed in the status line, which is very helpful to understand URLs.
“Web” is a shorter form of World Wide Web,
other common short forms are WWW, W3 and W3. The
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web
provides a means of accessing an enormous collection of information, including
text, graphics, audio, video, movies and so on. One of the most exciting
aspects of the web is that information can be accessed in a nonlinear and
experimental fashion. Unlike reading a book by flipping to the next page in
sequential order, you can jump form topic to topic via hyperlinks. This
nonlinear approach to information gathering or browsing is sometimes referred
to as “surfing the web” . Different
readers will proceed through the same web presentations in totally different
ways, depending on their backgrounds, needs, and personalities.
Web Terminology
WebPages or Files:- The Global collection of documents
associated and accessible via the world-wide-web
(w3 or www)
Hyper media: Media with links and navigational tools
Web Presentation: Collection of associated and hyperlinked web
pages
Web master: A person who maintains, creates (or web
manager) and manages a web presentation for a
organization
Website: An entity on the internet
that publishes web pages. For example www.Microsoft.com where www.microsoft.com/index.html is the
name of a web presentation
Web
Server: A computer that satisfies user requests for web pages
Mirror site: A site
that contains a duplicate copy of a web presentation from another site. If one
server is down a mirror site can be
tried if exists
Brief
note on URL (Uniform Resource Locater)
The
world-wide-web is the universe of network accessible information, the
embodiment of human knowledge. A URL is a compact string which represents the
location for a resource that is available via the internet. Typing a URL in the
location area or address bar and hitting the return key will cause the browser
to attempt to retrieve that page. If the browser is successful in finding the
page the browser will render and display it. To do this the browser needs to
answer following three questions
1. How can
the page be accessed
2. Where can
be page be found
3. What is
the resource name corresponding to the page
The URL is designed to incorporate sufficient
information to resolve above three questions
Format of URL
How://where/what
Example: http://microsoft.com/package/os/index.htm
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1. Http – Defines the protocol
or schema by the which the page being accessed. In the above example, the
protocol is hyper text transfer protocol. This is the set of rules by which an
html document is transferred over the web. Other protocols that may occur in URL
are ftp, gopher, mailto, news and telnet.
https –
Hypertext Secure ftp – File Transfer Protocol gopher – Gopher
mailto – sending
e-mail news – Requesting news telnet – Remote login
2. Second
part in the URL identifies the domain name of the computer where page resides.
The computer is the web server capable of satisfying page requests.
In the above example
“Microsoft.com package/os/” tells the browser where to find the webpage.
3. The
last part of the URL provides the local name usually a file name to identify
specific page uniquely. If no name is specified the web server may supply
default page or file. On many systems the default file is
named as index.htm or index.html
Examples
of URL
http//:www.mail.yahoo.com
http//:www.englishlearnings.com
Web page
Installation
In order to view your pages on the web, you
need to install them on a web server. A web server is a
program located on a
computer with internet access that responds to a browsers request i.e., web
server meets the demands of users by supplying the web pages requested. Ideally
the server should have an uninterrupted internet connected. So, that the pages
it handles, are always available. Many ISPs (Internet Service Providers)
include space on a web server as part of the basic set of services covered in
their monthly fee. The system administrator whose is responsible for the server
will provide specific details for publishing your web pages.
Requirements
for web page installation
1. You need
to have web pages to publish
2. A
web-server where the files can be placed must be available to you and you need
to learn the steps to put the files in the appropriate place (uploading)
3. The
permissions on the file need to be set, so that any user any where can print
them (world readable)
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4. When
some one request your web page with valid URL, the server has to deliver it.
All above details of exactly how these steps are performed var
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