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What is the Internet?
This is
harder to define than one might think. The simplest definition might
be that the Internet is a network. More precisely, it is a network
of networks. So what is a network? Two or more computers connected
together to communicate and share resources. The resources may be a
printer on another machine, or a software program like a word
processor. But most importantly, at least for the World Wide Web and
other common Internet services, a network allows the sharing of
files (where each computer stores its information).
File
sharing is significant because it allows a person on one computer to
access information stored on another. The two computers may be as
close as the same room, or in opposite corners of the world, yet the
information in the remote files may be available nearly instantly.
This technological development in communications is revolutionizing
the flow of information. The Internet is a network of smaller
networks that spans the globe. You can share data with a researcher
in Brazil, ideas for a project with a partner in Canada, or have a
live "conversation" with a friend from Australia as readily as you
might telephone your neighbor next door.
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Is the World Wide Web (WWW) the same as the
Internet?
Strictly
speaking, the WWW is a subset of the Internet even though they are
often referred to interchangeably. This is probably because in terms
of how they're used, the WWW is functionally the same as the
Internet for most people in most circumstances. For example, e-mail
is a widely used Internet service which has nothing to do with the
WWW. But many people use web browser software to read e-mail. In
fact the browser is the only Internet software many people use, and
they view the whole Internet through this
one interface.
Technically these are suites of many different applications
(browser, e-mail, newsreader, ftp client, etc.), but that doesn't
change the perception that they are all an extension of the same
experience.
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What is meant by "the web"? Is it the same as the
WWW?
The "web"
is simply one of the nicknames for the World Wide Web. Others
include "WWW" and "W3". They all refer to the same concept -- that
of many computers connected via various
networks so that
any computer can share resources seamlessly with any other. (Some
would say that eventually all computers will be connected).
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How do websites work?
Information
is transferred on the Internet using many different methods known as
protocols.
These are basically the means that the two computers "agree" to use
to communicate. The protocol determines how one computer requests
data, and how the other responds to those requests.
The web
uses the hypertext transfer protocol. The Internet is notorious for
acronyms, so this is usually referred to simply as HTTP. When
visiting a website, your browser (the client) requests an HTTP
connection with the computer that hosts that site (the server). If
the connection is successful, your browser requests the page you
want to view from the server and, if available, the server sends it.
The page itself is a document that someone most likely created with
hypertext markup language, or HTML. This is the language, or code,
that web browsers understand. (If you want to see a little of this
code, your browser should have a menu item to let you see it. In
Netscape try "View/Page Source" or in Internet Explorer try
"View/Source".) As the page is downloading from the server, your
browser interprets the html and displays the resulting content on
your computer. It may contain text, pictures, animations, sound,
movies, information forms, interactive games, and so on. It is
likely also to contain links to other pages. Clicking on a link will
tell the server to send that page. If the link is to a document at
another site, the whole process begins again, but with the server at
the new location. This linking of documents with html allows you to
access any referenced document as seamlessly as if it were on your
own computer.
For
instance, when you are looking at the Earth Village website, your
computer has requested the web page from a server located in the United
States.
The Earth Village web server sends the data you've requested over
the Internet to your computer, no matter where you live. Earth
Village also has links to other websites. With a click of your mouse on a
link, you can access web servers around the world.
Simply
put, the World Wide Web is a way to share resources with many people
at the same time, even if some of those resources are located at
opposite ends of the world. If you think of it as a research paper
that lets each footnote take you right to the original source, then
you've got the basic idea.
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What is a web browser?
A web
browser is the software you use to browse the World Wide Web. Its
primary purpose is to make an HTTP connection with a server machine
that has HTML documents you want to view. It then downloads the
pages, interprets the HTML, and displays it on your computer. If
that's a little confusing, take a look above at
"How do websites work?"
As more
people have begun using the web, the companies that develop browser
software have included more and more functionality. The most popular
web browsers can also be used for e-mail, Usenet newsgroups, FTP
client, HTML editing (creating web pages), address books, and much
more. For many people, this is the only software they need to access
the Internet.
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Does it matter which web browser I use?
Not really.
That is unless you think it does. The two most widely used browsers
are
Internet
Explorer and
Firefox. They are both available for free and provide similar,
though not identical functionality.
So why
would you choose one over any other? Cost and/or usability would
probably be at the top of most people's list. Cost is pretty easy to
figure out. Usability can be less straightforward. Adding
capabilities isn't always a plus. The increased size can cause it to
load more slowly and take longer to perform it's tasks. You may also
decide that the greater number of capabilities comes at a cost. It
does few of them well. Some people prefer having specialized
applications which are smaller and do their job very well. Others
prefer the Swiss army knife approach. That choice is up to
you.
There's at
least one more reason some people might choose a different browser.
They prefer David over Goliath, or maybe even the other way around.
Some people dislike both FireFox and Microsoft. They are both
guilty of being willing to sacrifice your web browsing experience
for their own gain by incorporating proprietary HTML into their
browsers. This means that a web site developed for their software
may not view as well with a browser from another company. HTML (the
language that web pages are created with) is an open standard which
was created, and is continually updated, precisely to avoid this
problem. But if they can gain a stronghold and enough sites are
created using their private "features", it may force people to use
their software out of necessity. If you don't care for this
practice, you might choose a different browser. Then again, some
people prefer to stick with a "winner".
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What does it mean to "browse" or "surf" the
web?
Browsing or
surfing the web is simply using a web browser to make connections to
and view websites. Surfing as a metaphor for this experience may be
derived something like this: Often times people find themselves
connecting to a website, following a link to another, then
another... and another... Before they know it, they've visited
numerous sites possibly encompassing all corners of the world. Some
sites are better than others, with more useful information or a
better presentation. Others have little to offer at all. And there
are almost always diversions and tangents along the way. This ebb
and flow of good and not so good sites, and things that can carry
you completely away from what you set out to do, is a little like
surfing.
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Why isn't "http://" needed in the address (URL) like it
used to be?
The protocols (e.g.
"http://", "ftp://", "gopher://") used to be necessary at the
beginning of a URL (Uniform Resource Locator) to get you connected
to the correct service at the remote (server) end of a connection.
As use of the hypertext transfer protocol or "HTTP" became more
widespread, web browsers were designed to default to this protocol
if none is specified. So, if your browser software is recent enough,
and you don't specify the protocol, HTTP is assumed. In fact, if you
look in the Location: box in some versions of Netscape Navigator
or the Address: box in MS Internet Explorer, you will see that
"http://" is inserted for you if you don't provide it.
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Is it safe to browse the web? For example, could my
computer get a virus?
Safety on
the web is the same as anywhere else. How safe it is is mostly up to
you, but there are always some things outside of your control no
matter how careful you are. If you haven't identified the risks of
driving a car before you get behind the wheel, it can be dangerous.
The same can be true of the web. As with anything , it's prudent to
learn something about the risks.
Following
are some general statements about the risks. These are not
definitive and there are exceptions, some of which are noted.
You must
download and run an executable program for your computer to be
infected by a virus. An executable program in the MS Windows world
is a file that ends in ".exe", ".com", ".cmd," or ".bat". These are
programs which actually run something, or execute instructions on
your computer. Other files like a web page, or the embedded graphics
can't pass a virus. The most important thing you can do to protect
yourself is to use only trusted sources when downloading programs
from the Internet. Downloading Internet Explorer from www.microsoft.com is a pretty safe thing to do. Downloading
"make$$$.exe" from www.sleazyoperator.com may not be. If you're
going to download programs and try them on your computer, invest in
anti-virus software and use it to check every download -- even from
trusted sources. (One of the commercial leaders in this market is
Symantec.) The anti-virus
software does not guarantee prevention from viruses, but does offer
a significant measure of protection. These companies are always
playing catch up with the malevolent people who create these things.
But they are generally very good at providing prompt responses to
new threats, and make updates to the software available
regularly.
Following
are some exceptions. MS Word and MS Excel documents can have macros
embedded in them that run automatically when you open the documents.
Even though they are not executable programs, the macros execute
instructions just as a program does. You should never open up a
document from someone you don't know, just as you wouldn't take
candy from a stranger on the street. Good anti-virus software will
detect macro viruses as well. Earth Village strongly
recommends that ALL computer users run an Anti-Virus program such as
Norton Anti-Virus produced by
Symantec
for added security.
Another
exception is web pages with active content. There are programming
languages which allow website developers to embed small programs,
usually referred to as applets, right into the web pages. The most
common of these are Java, and Active-X. Most of these are harmless
and do simple things like changing the look of a graphic when your
mouse passes over it. But applets may have the same risks as
executable programs. In practice, the talk about the risks greatly
exceeds the number of observed occurrences. But if you'd prefer to
err on the side of caution, these can be disabled in the
configuration of your browser software.
Finally,
there are risks besides viruses. And it doesn't always require
downloading something to encounter them. Computer operating systems
(e.g. Windows) and application software (e.g. Netscape Navigator)
are very complicated programs, sometimes using millions of lines of
programming code to make them work. Security problems are regularly
found buried in these mountains of code. For example, some time ago
Microsoft discovered that if you had MS Excel installed on
your computer, it was possible for a website operator to download
your excel data files while you browsed their site, without notifying
you. When it was discovered, Microsoft made a patch (a program which
fixes the problem) available on their website.
We mention this not to heighten fears about safety, but to point out
that not knowing about the risks can be as dangerous on the web as
anywhere else. Most of us will drive a car our whole lives without
having an accident. But we still use our seat belts and carry
insurance. If you use a computer and the Internet, you should
probably know where to find security information for the software
you use, and update it frequently. You will probably never need it, but you'll be glad
you stayed prepared if you
do.
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Is it safe to make credit-card purchases on the
web?
The short
answer is that it is no less safe than making a credit-card
purchases over the telephone. As with everything, who you're doing
business with is more important than how you're doing it. It is
always safer to do business with a trusted source, whether on the
Internet or not.
A slightly
more detailed answer is, if your browser is a recent version it
probably has encryption capabilities. This means that the
information you send is scrambled so that it is virtually impossible
to decode it, which is definitely more secure than ordering over the
telephone. Encryption isn't always an option because it must also be
enabled at the site where you're doing business . If this is a
concern for you, you can choose not to do business with sites that
don't offer it. However, even without encryption, it is still
probably more secure than ordering by telephone.
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What about privacy? What information can people gather
about me?
The answer
to this question is very similar to the issue of
safety on the
web. The risks to privacy aren't necessarily greater, just
different. And not understanding them, at least at a basic level,
can be just as damaging as anywhere else. There are many things that
you can do to protect your privacy if you choose.
When
visiting a website, you are sometimes asked for information about
yourself. If you're not comfortable with the request, don't answer
it.
There are
other ways your privacy can be compromised, one of which is
"cookies". The most widely used browsers support a method of
information collection called a cookie file. This is a file on your
computer where websites can write and retrieve information about
your visits. There are many opinions about cookies. They weren't
intended to be invasive, but were created to help websites to
optimize your visits. In practice, they can be used intrusively and
so some consider them bad by definition. For example, a website can
track which areas you visit, store the information on your computer
then retrieve it on your next visit. You may then be presented with
information about pages that have changed in your areas of interest.
Or you may be presented with specifically targeted advertisements.
Whether either of those is intrusive is probably a matter of
personal opinion. Also it is often possible to determine where you
came from before arriving at a site. By itself this information
means little, but some people have concerns that this information
could be used to create a fairly comprehensive profile of your web
viewing habits. Again, it is probably a matter of personal opinion,
but some people would find this distasteful.
Cookies
can also protect you, however. Some sites use them as a part
of the security measures to see that the people entering the site
should be there. Often, disabling the "cookie"
feature means losing your access to access that is important to
you. Most browsers do allow you the choice of turning cookies
on or off; how often you want to change the settings then becomes a
personal preference.
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What are protocols?
In
information technology, protocols are the special sets of rules that
two computers "agree" to use to communicate. One basic purpose of
protocols is to make it possible for computers and networks of
differing platforms to communicate. The different platforms could
refer to hardware (e.g. a mainframe computer at a large company, an
individual PC, or an Apple computer) or to software (e.g. MS
Windows, Unix, or Mac OS). Each platform performs communications,
and accomplishes most other tasks, in very different ways. Protocols
which can be implemented across, or without regard to platforms make
it possible to bridge these differences.
If you've
been around computers, or read about them, you've probably heard
about some protocols. Even if you didn't know it. If you've been on
the Internet, or read about it, you can't help but to have heard
about protocols. One you have probably seen mentioned is HTTP
(Hyper-Text Transfer Protocol). This is the protocol that computers
use to transfer web pages, and is one of the higher level protocols
common on the Internet.
To
understand protocols, you will want to understand that computer
networking consists of multiple layers of protocols. We don't need
much more detail than that for our purposes, but you should keep in
mind the fact that there are different layers. We referred already
to HTTP as a higher level protocol. This means that it, and others
like it, are used at the level of your application software (e.g.
Netscape Navigator, or MS Internet Explorer). Some of the others
like it are SMTP (Simple Mail Transfer Protocol), FTP (File Transfer
Protocol), NNTP (Network News Transfer Protocol), and Telnet (which
you might be pleased to know, does not have an acronym).
You may
recognize some of these from the
beginning of
URL's you've typed into a web browser. These protocols determine
how specific information is requested, sent, and received between
two computers. When you type a URL that begins with something like
"http://", "ftp://", or "telnet://" into your browser, it is
requesting that information be transferred using that protocol.
(There are other ways besides a web browser to accomplish this, but
the concept is the same.) If the requested service is available, the
remote computer opens up a connection of that type between your
(client) software and the remote (server) software. If the remote
machine offers more than one of these services, there is server
software running for each of them, and the protocol determines which
one is going to handle your requests. Any client or server software
can communicate with any other, regardless of the version, as long
as they both adhere to the protocol. This is why you can use
Netscape, Outlook, Eudora, Pine, Elm, or a host of other software
packages to read and send e-mail. They all "talk" SMTP.
You may
reasonably wonder why one such protocol isn't enough, and it's
because they each do different things. For instance, SMTP delivers
e-mail from one specific user to other specific user(s). Usenet newsgroups use NNTP, and these messages
propagate themselves
throughout the Usenet system so that anyone connecting to an NNTP
server can view them. They are an open discussion forum, and access
is not limited to any specifically targeted user(s). Simple file
transfers use FTP (e.g. downloading a new version of your web
browser software for installation). The Telnet protocol provides an
interactive command shell (similar to a DOS command-line) that
executes commands on the remote machine that you enter on your local
machine. For example, you could make a telnet connection from home
to your office and do things like renaming files, making and
deleting directories (folders), and just about anything else you
could do if you were actually sitting at the computer in your
office. So you can see that each of these provides much different
functionality to the user, and consequently needs different rules or
protocols for accomplishing its own tasks.
Below this
layer of networking protocols are others that operate at a lower
level. Logically, we've presented these in reverse order since each
higher level is built upon the lower ones. The order we chose here
is because the higher ones are more important for the purposes of
this discussion, but there is one set of lower level protocols to
which you'll see frequent references. That is TCP/IP, which plays a
fundamental role both in how the information is broken down into
pieces (packets) which can physically be transferred over the
network, and also in making sure those packets get to and from the
proper locations. Basically, once your computer has made a
connection with a remote computer and has agreed upon a higher (or
application level) protocol, the baton passes to TCP/IP for the job
of actually transferring the information on behalf of that
particular protocol. That's kind of a mouthful, but the following
might help if you've gotten this far, and care to continue a little
bit further.
"TCP/IP
(Transmission Control Protocol/Internet Protocol) is the basic
communication language or protocol of the Internet. It can also be
used as a communications protocol in the private networks called
intranets and in extranets. When you are set up with direct access
to the Internet, your computer is provided with a copy of the TCP/IP
program just as every other computer that you may send messages to
or get information from also has a copy of TCP/IP.
TCP/IP is a
two-layered program. The higher layer, Transmission Control
Protocol, manages the assembling of a message or file into smaller
packets that are transmitted over the Internet and received by a TCP
layer that reassembles the packets into the original message. The
lower layer, Internet Protocol, handles the address part of each
packet so that it gets to the right destination. Each gateway
computer on the network checks this address to see where to forward
the message. Even though some packets from the same message are
routed differently than others, they'll be reassembled at the
destination.
TCP/IP uses
the client/server model of communication in which a computer user (a
client) requests and is provided a service (such as sending a Web
page) by another computer (a server) in the network. TCP/IP
communication is primarily point-to-point, meaning each
communication is from one point (or host computer) in the network to
another point or host computer. TCP/IP and the higher-level
applications that use it are collectively said to be
"connectionless" because each client request is considered a new
request unrelated to any previous one (unlike ordinary phone
conversations that require a dedicated connection for the call
duration). Being connectionless frees network paths so that everyone
can use them continuously. (Note that the TCP layer itself is not
connectionless as far as any one message is concerned. Its
connection remains in place until all packets in a message have been
received.)
Personal
computer users usually get to the Internet through the Serial Line
Internet Protocol (SLIP) or the Point-to-Point Protocol (PPP). These
protocols encapsulate the IP packets so that they can be sent over a
dial-up phone connection to an access provider's modem."
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