The World Wide Web by leader6

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									                              The World Wide Web

The www, the graphical portion of the Internet, is the most popular part of the Internet
by far. The Web allows rich and diverse communication by displaying text, graphics,
animation, photos, sound video.

So just what is this miraculous creation? The Web physically consists of your
personal computer, web browser software, a connection to an Internet service
provider, computers called servers that host digital data and routers and switches to
direct the flow of information.

The Web is known as a client-server system Your computer is the client; the remote
computers that store electronic files are the servers. Here's how it works:

Let's say you want to pay a visit to the University of Ulster's website. First you enter
the address or URL of the website in your web browser. Then your browser requests
the web page from the web server that hosts the University's site. The University's
server sends the data over the Internet to your computer. Your web browser interprets
the data, displaying it on your computer screen.

The University's website also has links to the sites of other museums, such as the
LEDU and the IRTU (Industrial Research Technology Unit). When you click your
mouse on a link, you access the web server for these sites.

The "glue" that holds the Web together is called hypertext and hyperlinks. This
feature allows electronic files on the Web to be linked so you can easily jump
between them. On the Web, you navigate through pages of information based on what
interests you at that particular moment, commonly known as browsing or surfing the
Net.

To access the Web you need web browser software, such as Netscape Navigator or
Microsoft Internet Explorer.
                                  Web Addresses


When you think of the Internet, you probably trunk of ".corn." Just what do those
three letters at the end of a World Wide Web address mean?

Every computer that hosts data on the Internet has a unique numerical address. For
example, the numerical address for the White House is 198.137.240.100. But since
few people want to remember long strings of numbers, the Domain Name System
(DNS) was developed. DNS, a critical part of the Internet's technical infrastructure,
correlates a numerical address to a word. To access the White House website,
you could type its number into the address box of your web browser. But most people
prefer to use "www.whitehouse.gov." In this case, the domain name is
whitehouse.gov.

In general, the three-letter domain name suffix is known as a generic top-level domain
and describes the type of organisation. In the last few years, the lines have somewhat
blurred between these categories.
.
  .corn -business ( commercial)
.edu -educational
.org -non-profit
.mil -military
.net -network provider
.gov -government

A domain name always has two or more parts separated by dots and typically consists
of some form of an organisation's name and the three-letter suffix. For example, the
domain name for IBM is "ibm.com"; the United Nations is "un.org. "

If a domain name is available, and provided it does not infringe on an existing
trademark, anyone can register the name for a nominal fee.

Of the over 8 million domain names, 85% are .corn domains.

In addition to the generic top-level domains, 244 national top-level domains were
established for countries and territories, for example:

.au- Australia
.ca -Canada
.fr -France ~
.de -Germany
.uk -United Kingdom

For a complete list of national top-level domains see :
http ://www .leamthenet.com/english/85tldn.htm
2 worldwideweb
           Locating Files and Sites: Uniform Resource Locator

How does your web browser distinguish between web pages and other files on the
Internet?

Web pages are written in a computer language called Hypertext Markup Language or
HTML.

The World Wide Web as a network of electronic files stored on computers all around
the world. Hypertext links these resources together. Uniform Resource Locators
(URLs) are the addresses used to locate these files. The information contained in a
URL gives you the ability to jump from one web page to another with just a click of
your mouse. When you type a URL into your browser or click on a hypertext
link, your browser is sending a request to a remote computer to download a file. E.g

http://www.ulst.ac.uk          The home page for the University of Ulster.

ftp://rtfm.mit.edu/pub/        A directory of files at MIT available for downloading.


The first part of a URL (before the two slashes) tells you the type of resource or
method of access at that address. For example:

http -a hypertext document or directory
gopher -a gopher document or menu
ftp -a file available for downloading or a directory of such files
news -a newsgroup
telnet -a computer system that you can log into over the Internet
WAIS -a database or document in a Wide Area Information Search database
file -a file located on a local drive (your hard drive )

The second part is the address of the computer where the data or service is located.
Additional parts may specify the names of files, the port to connect to, or the text to
search for in a database.

You can enter the URL of a site by typing it into the Location bar of your web
browser, just under the toolbar.

Most browsers record URLs that you want to use again, by adding them to a special
menu. In Netscape Navigator, it's called Bookmarks. In Microsoft Explorer, it's called
Favorites. Once you add a URL to your list, you can return to that web page simply
by clicking on the name in your list, instead of retyping the entire URL.

Most of the URLs you will be using start with http, which stands for Hypertext
Transfer Protocol. http is the method by which HTML files are transferred over the
Web. Here are some other important things to
know about URLs:
    A URL usually has no spaces.
    A URL always uses forward slashes (//).
    If you enter a URL incorrectly, your browser will not be able to locate the site
     or resource you want.
    Should you get an error message or the wrong site, make sure you typed the
     address correctly.




                                  BOOKMARKS

With millions of websites and more coming online daily, you will undoubtedly find
ones you want to revisit. Bookmarks or Favorites save the addresses of your favourite
sites so you can return to them quickly, without having to retype the addresses.
Whether you are using Netscape Navigator or Internet Explorer, the procedure is
similar.

Once you find a site you want to save, go to the Bookmarks or Favorites menu or
click on its icon and select Add. When you click on the icon again, the title of the web
page you recorded will appear at the bottom of the list. To revisit a bookmarked
website, just double-click on it.

TRY THIS...
To bookmark the University's home page, select this hyperlink
http://www.ulst.ac.uk./
When located, click on it once with your right mouse button and select Add
Bookmark or Add to Favorites from the pop-up menu.

Putting Your Links in Order
Soon you will discover that you've got dozens of bookmarks. It's now time to organise
them into folders.

If you use Internet Explorer 5.0, click on the Favorites button on the toolbar to open
the Favorites window. Now select Organise Favorites. Click on the folder icon to
create a new folder, then name it. We suggest organising your bookmarks in folders
by subjects, such as Business, Personal, Finance, etc. Now click on each Favourite
once, hold down your left mouse key and drag the appropriate Favourite into the
subject folder.

If you use Navigator 4.0 or a later release, click on the Bookmarks icon to view all
your bookmarks. Under the File menu, select New Folder. In the Name box, type in a
name for the folder, then click on OK. Now return to your list of bookmarks, click
once on one to highlight it, then drag it into the appropriate subject-related folder.
Repeat the process for the other topics and bookmarks.

Sometimes the names of the bookmarks aren't descriptive, so you may want to alter
them. With Navigator, select the bookmark you want to change by clicking on it once.
Go to the Edit menu and choose Bookmark Properties. Now type in the new name and
click OK.
With Explorer, open the Favorites window, then click on Organise Favorites. After
the dialog box opens, click on the favourites you want to change. Next, click the
Rename button. Now you can type a new name.



                             SEARCH STRATEGIES

With hundreds of millions of web pages online, you could spend a lifetime surfing the
Web, following links from one page to another. Amusing perhaps, but not very
efficient if you are after some specific information. One of the biggest complaints we
hear concerns the difficulty of finding targeted information. Where do you start?
Searching the Internet requires part skill, part luck and a little bit of art. Fortunately, a
number of free online resources can help with the hunt.


You've probably heard of Yahoo!, Excite, AltaVista and other so-called Internet
search engines. There are literally dozens of these tools to help you locate what you're
looking for. The trick though, is understanding how they work, so you can use the
right tool for the job.

Search engines breakdown into two categories--directories and indexes.

Directories, such as Yahoo!, are good at identifying general information. Like a card
catalogue in a library , they group websites under similar categories, such as Internet
tutorials, English universities and Paris museums. The results of your search will be a
list of websites related to your search term If you are interested in locating the site for
the Louvre museum, for instance, uses a directory .

But let's say you want more specific information, such as biographical information
about Leonardo da Vinci. Web indexes are the way to go, because they search all the
contents of a website. Indexes use software programs called spiders or robots that
scour the Internet, analyzing millions of web pages and newsgroup postings, indexing
all of the words.

Indexes like Alta Vista and Lycos find individual pages of a website that match your
search, even if the site itself has nothing to do with what you are looking for. You can
often find unexpected gems of information this way, but be prepared to wade through
a lot of irrelevant information too .

Search results are usually ranked in order of relevancy--the number of times your
search term appears in a document, or how closely the document appears to match a
concept you have entered. This is a much more thorough way to locate what you
want.

Perform an online search using three popular search engines-- Yahoo!, AltaVista, and
Ask Jeeves--so you can see how they work and how you can develop an efficient
search strategy.
TASK: You are planning a trip to San Francisco and you've always wanted to ride on
a cable car. Do theyoperate in January? How can you find out?

The first thing to ask is: "How would I get this information in the real world?"
Perhaps you would consult a travel guidebook. So let's start with that premise

Using Yahoo! In the search box, type in San Francisco travel guide. Be as specific as
possible to narrow the scope of the search. Just entering "San Francisco " will result in
thousands of results. By adding the additional words, "travel guide," there's much
fewer.

The search returns twelve categories, one of which, San Francisco: Travel, looks very
promising. By clicking on this category, you get a list of about 20 related websites,
along with a brief description of each one. Now you have to visit each site to see if
there's any information about cable cars.

What happens if you just do a search for "cable cars?" Yahoo! returns a list of
categories with only a few related to San Francisco. So much for directories.
                  Characteristics of different search engines

AltaVista creates complete indexes of every word on every web page or Usenet
newsgroup it encounters, allowing you to perform highly targeted searches. Alta Vista
searches by keywords that it culls from the text of a web page. It indexes millions of
web pages and articles from Usenet newsgroups. Alta Vista updates its information
constantly and each page returned from the search is given a date and time from Alta
Vista's most recent update.

An interesting feature of Excite is its "Confidence Rating," a percentage rating given
to each of the results it returns; a higher percentage indicates a closer match to your
original query .In addition, Excite gives you the option to view more documents
similar to those described in that particular result. Excite is available in a number of
languages.

HotBot performs fast and powerful keyword searches of websites and newsgroups.
Search results are ranked according to a confidence rating. You can search for images,
video and MP3 files and also search in different languages.

InfoSeek, part of the Go Network, searches by keywords, scanning the information in
its database, including the web and Usenet. Infoseek scores your search results,
returning the best matches to your query.


Yahoo!, the most popular hierarchical directory, is a good starting point. You can
search by category, or like the other search engines, you can specify a search term.
Yahoo! works well if you're searching for general information, but because of the way
Yahoo! indexes information, you probably won't get great results if you're looking for
something specific or very recent.



                                Search Techniques
Regardless of which search engine you use, it really pays to find out the particulars of
how it works. Take time to read the search tips on the respective sites. For instance,
how does the engine handle searches that include more than one word? Most engines,
but not all, return results that include any of the words. Because there is so much
information online, you will usually want to limit the scope of your searches. How do
you do this?

Searching...                   Results in...

cable AND car                   Documents with both words
cable OR car                   The greatest amount of matches; documents with either
                               word
cable NOT car                   Documents about cable, but not about cable cars; a
                               good way to limit the search.
                                Subject Directories

Yahoo!           http://www.yahoo.com
This huge subject directory has been around since 1994 and is a great place to browse
for Internet resources. You can also search this index or access other popular search
tools. Although Yahoo! is a very useful starting place, some pages are long and time-
consuming to wade through, few sites are reviewed, and there are numerous dead
links.

Mining Company           http://www.miningcompanv.com
This unique and very helpful service offers hundreds of subject guides to Internet
resources. Each guide is maintained by an individual with expertise or keen interest in
the topic, is annotated to help you decide which sites to visit, and is updated weekly.
This is the place to quickly find the best sites on a topic.

LookSmart http://www .looksmart.com
Recommended Web sites arranged by subject. Links include brief, but helpful,
descriptions.

Snap http://www.snap.
This growing subject directory features brief reviews of selected Web sites.

Starting Point         http://www.stpt.com
A popular place to start exploring the Internet. Selected links are arranged by topic.

Argus Clearinghouse             http://www.clearinghouse.net
Offers links to topic-specific directories.


                                  Search Engines

Alta Vista       http://www.altavista.corn
Search the full text of Web pages and Usenet news articles. Alta Vista's size, speed,
low rate of dead links, and multiple search options make it one of the most popular
search engines. Beginner's may find the syntax required for advanced searches tricky .


HotBot          http://www.hotbot.com
This has one of the largest indexes of Web pages and offers lots of advanced search
features to help you narrow your queries. You can search Web sites, newsgroups,
email addresses, and much more, plus browse a smaller selection of sites by category.

InfoSeek       http://www.infoseek.com
You can look for newsgroups, email addresses, Reuters news, company information,
Web FAQs and browse InfoSeek's subject "Channels".

Excite http://www .excite.com
This is unique because in addition to regular search features, it offers concept
searching. For instance, if your search includes the term 'fi1m', Excite will also search
for 'movie'. At Excite you can search the WWW, newsgroup articles, and browse Web
site reviews, CityNet, a reference section, news,
and more.

Lycos           http://www.lycos.com
Searching the Net is easy using Lycos' pop-up menus to select search options. If
you're not certain what you're looking for consult Sites by Subject, Point Review or
sections on sounds and pictures, telephone numbers, and road maps. The Lycos search
engine focuses on popular sites, so if you're looking for a scientific or technical topic
try another search tool.



Northern Light          http://www.northernlight.corn
This is unique because it presents search results in a set of "custom" folders based on
subject, type, source, or language. Pick folders and subfolders to narrow your search.
You can also search magazines but you must pay to receive the articles.


WebCrawler           http://webcrawler.corn
A good basic search engine accompanied by a subject index for browsing popular and
outstanding sites.

								
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