INTERNET

What is Internet?

The Internet is many things to many people. Erik-Lars Nelson, a New York
Daily News columnist, famously called it “. . . a vanity press for the demented,
the conspiratorial or the merely self-important.” A newspaperman, Nelson
lamented the fact that information presented on the Internet does not have
to undergo a rigorous examination as to its accuracy. Whereas newspapers
hold themselves to standards of truth and employ editors and fact-checkers
to make sure what they print is accurate, fools can say whatever they want
on the Internet — and they do so with complete confidence that somebody,
somewhere will believe them.
In contrast to Nelson’s dim view of the Internet, others describe the Internet
in utopian terms. To these people, the Internet is a vast town meeting in
which everyone can participate and everyone’s voice is heard. The utopians
see the Internet as a valuable tool for democracy and knowledge, a sort of
international conversation for the greater good.

What Is the Internet?
So what is the Internet? By the time you finish reading this book, you will
decide for yourself. Meanwhile, here are some activities you can do on the
Internet:
✦ Research a topic: If you know how to conduct a meaningful search, you
can nearly always find the information you need on the Internet. Book II
explains researching on the Internet. Figure 1-1 shows the home page of
Alta Vista, a search engine.
✦ Get the mail: E-mail, or electronic mail, travels much faster than conventional
mail. An e-mail message you send this instant can take as little as
three seconds to reach its recipient, although you can’t enclose a lock
of hair or scent your e-mail message with evocative perfume. Book III
explains e-mailing.
✦ Connect to other researchers: By joining newsgroups, mailing lists, and
Yahoo! groups, you can get information about many different topics from
other Internet researchers. Book IV looks into this subject.
✦ Trade instant messages: If you have teenagers, I bet you already know
about instant messaging. Instant messaging permits a dozen or more
people to gossip with one another while exercising their fingers on the
keyboard.

HOW INTERNET WORKS

ARPANET was the forerunner of the Internet. In ARPANET, data did not pass
through a central hub; instead, all the host computers were connected to
all the other host computers. This revolutionary decentralized design permitted
data to take many different routes from one computer to another
because the computers were interconnected. And if one part of the network
failed, the network’s interconnectedness made it possible for other parts
to pick up the slack and continue transmitting data by a different route.
Moreover, the decentralized structure of ARPANET made it easier to add
computers to the network.
In the beginning, only four host computers — computers that other computers
can connect to, similar to what we call Web servers — were available on
ARPANET, but universities and research centers soon understood the value
of being able to collaborate over a network, and more host computers were
added. By 1971, there were 23 host computers on ARPANET. In 1972, e-mail
was invented so that researchers could quickly exchange messages, and network
traffic increased dramatically. In 1977, ARPANET featured 111 host computers.
By 1989, ARPANET had become a “network of networks,” with some
100,000 host computers.
ARPANET had turned into the Gargantua that we call the Internet. ARPANET’s
designers envisioned an interconnected networkwith no central authority to
which new networks could be added. ARPANET succeeded beyond its designers’
wildest dreams. Estimates of how many people worldwide use the Internet
range from 600 to 730 million. In 2001, for the first time, the number of hours
that Americans watch television shrank because the Internet had become an
alternative to television watching. Today, no single organization controls the
Internet. Each organization with a host computer is responsible for maintaining
its part of the Internet so that data packets can speed merrily along to
their destinations.
The Open Directory Project, a Web directory maintained by volunteers,
offers a Web page with links where you can get statistics about Internet use.
The Web page is located at this address: http://dmoz.org/Computers/
Internet/Statistics_and_Demographics.


The World Wide Web
The early Internet was strictly for academics and researchers. To retrieve
documents, you had to know advanced programming commands. You had to
remember arcane numerical Internet addresses. Each host computer had a
different command set for accessing files.
Starting in the late 1980s, however, innovations in computer science made
the Internet available to everyone. In 1989, a protocol called http, or hypertext
transfer protocol, made it easy to transfer files over the Internet. In computer
terminology, a protocol is set of rules by which computers communicate with
one another. You no longer had to learn a different set of commands to transfer
a file from a host computer to your computer because each host computer
stuck to the http standard. The letters http at the start of Web addresses refer
to the hypertext transfer protocol (see Figure 1-2).
The late 1980s also saw the invention of the World Wide Web, also known
simply as “the Web.” The letters www in Web addresses stand for World
Wide Web (refer to Figure 1-2). The man who coined this term, a computer
scientist named Tim Berners-Lee, called the Web “the universe of networkaccessible
information, an embodiment of human knowledge.” Berners-Lee
was one of those utopians I mention at the start of this chapter. In prosaic
terms, the World Wide Web is just the sum of all the files — the Web pages,
audio files, movie files, and computer programs — that you can bring into
your computer from the Internet by way of the hypertext transfer protocol.

Web addresses
Besides inventing the term World Wide Web, Tim Berners-Lee invented the
addressing system for locating files on the Web. Previous to this system, you
had to enter a hard-to-remember IP address number to visit a Web site, but
the system replaced numbers with descriptive domain names. In the system,
file addresses are designated by a domain name and then by a folder name
within the domain. To see how Web addresses work, consider the address of
the Web page shown in Figure 1-2:
http://www.ruthasawa.com/Pages/AsawasArt.htm
A computer reads this address like so:
✦ http://: The file at this address can be transferred using the hypertext
transfer protocol.
✦ www: The file is located on the World Wide Web.
✦ ruthasawa.com: The domain name of the Web site to connect to is
ruthasawa.com. The next section in this chapter explains what domain
names are and how computers use them to locate computers on the
Internet. The .com ending on the domain name tells you that the site is
commercial (for-profit) in nature.
✦ /Pages: Within the ruthasawa.com Web site, the file is found in a folder
called Pages. Files on Web sites are stored in folders, just as files are
stored in folders on your computer.
✦ /AsawasArt.htm: The file to be transferred is called AsawasArt.htm.
The .htm file extension means that the file is written in hypertext
markup language.
The addressing convention that Tim Berners-Lee invented made it possible
for computers to quickly locate and download files from the World Wide
Web. His addressing convention also made the Web more weblike. Now that
everyone agreed on how to address Web pages, linking Web pages became
much easier. Hyperlinks began appearing on Web pages. For the first time,
you could point to and click a hyperlink on one Web page and go straight
to another page. (By the way, Berners-Lee called Web addresses uniform
resource locators, or URLs, a term that is thankfully falling out of favor. I only
mention URLs here in case someone mentions them to you and you want to
nod your head wisely because you know what URLs are. In this book, I refer
to URLs as Web addresses.)

How the Internet Works
More computer science innovations brought the Internet even closer to
home. Faster modems decreased the amount of time you had to wait for Web
pages to arrive on your computer. In the early 1990s, the first Web browser,
Mosaic, appeared. Now a program made especially for exploring the Internet
was available. Also in the mid-1990s, the Java computer language made it
possible to incorporate video and sound on Web pages. And don’t forget the
mouse! All hail the mouse! Where would we be without it? You can explore
the Internet for hours at a time without touching the keyboard thanks to this
furry little animal. And it’s amazing that the mouse didn’t become a computer
apparatus on Macs until 1986 and on PCs until 1987.

IP addresses
Every computer that’s connected to the Internet has an Internet Protocol
address, better known as an IP address. Computers use these addresses to
locate data and to send data over the Internet.

Want to know your computer’s IP address?
Follow these steps to find out your computer’s
IP address:
1. Choose Start➪Programs➪Accessories➪
Command Prompt (choose MS-DOS instead
of Command Prompt if you are running
Windows 98 or Windows Me).
The Command Prompt window opens.
2. Enter ipconfig and press Enter.
The window shows you information about
your computer, including its IP address.
Here’s an even faster way to find out your IP
address. Open your Web browser, enter this
address in the Address bar, and press Enter:
www.whatismyip.com

If yours is a DSL Internet connection or cable modem connection, your IP
address is permanent and unchanging. If yours is a dialup Internet connection,
your Internet provider assigns you a new IP address each time you connect
to the Internet.
An IP address is a 32-bit (4-byte) binary number, which needn’t concern you
very much. The point is that the number identifies a computer on the
Internet. Here is an example of an IP address:
216.239.39.99
Each domain name — google.com, yahoo.com, and microsoft.com, for
example — is assigned an IP address. The IP address just listed, for example,
belongs to the domain name google.com. When you enter a Web address in
your browser to view a Web page, your computer takes note of the domain
name part of the address (google.com, yahoo.com, or microsoft.com,
for example) and sends a query to a domain name server asking for the IP
address that’s assigned to the domain name. The domain name server, in
turn, sends the IP address of the domain name back to your computer. Your
computer then sends a request for Web-page files from the IP address in
question, and in less than a second, if you have a fast Internet connection,
a Web page appears on your computer screen.

Something similar happens when you send an e-mail message. Your computer
sends a query asking for the IP address of the domain name, the
part of the e-mail address after the at (@) symbol. When the IP number is
returned, the e-mail message is sent.
To see how IP addresses work, try this simple exercise:
1. Open your Web browser.
2. In the Address bar, type www.google.com and press Enter.
Your browser opens to the Google home page, as shown at the top of
Figure 1-3.
3. Delete the www.google.com in the Address bar and enter the
following:
216.239.39.99
4. Press Enter.
You see the Google home page again, as shown at the bottom of
Figure 1-3, because the number you entered in Step 3 is the IP address
of google.com.

In the old days, before the domain-name addressing system for locating files
on the Web, you had to enter IP addresses. Aren’t you glad you don’t live in
the old days? Entering descriptive Web addresses sure beats entering 32-bit
binary numbers.
Finding a Web site’s IP address
If you are called on to play Internet detective and find the IP address of a
Web site, you can follow these steps to find it:
1. Choose Start➪Programs➪Accessories➪Command Prompt.
If you are running the Windows 98 or Windows Me operating system,
choose MS-DOS instead of Command Prompt. You see the Command
Prompt window.
2. Enter ping and a blank space.
3. Enter the domain name of the Web site whose IP address you need.
Domain name IP address
Figure 1-3:
Normally,
your
computer
enters the
IP address
for you.
For example, to find the IP address of google.com, enter google.com, as
shown in Figure 1-4.
4. Press Enter.
The Command Prompt window tells you the Web site’s IP address (refer
to Figure 1-4). Notice the “approximate round trip times in milli-seconds”
in the Command Prompt window. It took my computer only 76 milliseconds
to ask for and receive the IP address of google.com. That’s less
than a tenth of a second. Information travels fast on the Internet.

How Web Pages Work
If a friend tells you to go to the such-and-such Web page because it is entertaining,
thought provoking, or funny, and you go there, you aren’t really
going anywhere. Really, the Web page is coming to you. The files with which
the Web page is composed come to your computer so that you can view
them.
All but the simplest Web page consists of many different files — text files,
graphic files, and sometimes animation, video, and sound files. To see what
I mean, take a look at Figure 1-5, a Web page from amazon.com. The top half
of the figure shows the Web page without the graphic images; in the bottom
half of the figure, you can see where the graphic image files have been
plugged into the Web page. This Web page consists of a dozen or more files.
When you bring a Web page like this to your computer, the image files tag
along behind the Web page. Hypertext markup language in the Web page
tells your Web browser where to plug in each tag-along file, and the result is
a full-fledged Web page.

Web pages are written in hypertext markup language, or HTML, the computer
language that tells the Web browser how to lay out and construct Web pages
from the different files with which they are made. Want to see something
scary? In your browser, choose View➪Source (in Internet Explorer) or
View➪Page Source (in Mozilla) to see the HTML codes with which a Web
page is constructed. Figure 1-6 shows some of the HTML code used to construct
part of the page shown in Figure 1-5.
These codes are scary, but don’t be discouraged if you want to create a Web
site of your own. Thanks to the miracle of modern computer science, you
can create Web pages and Web sites without having to know or write HTML
codes.