Download 1 - Digitalist

9. The Internet
While not everything on the syllabus is mentioned in these notes, they provide you
with a sound theoretical basis for this topic.
In the 1950s the United States Department of Defense started working with the
RAND Corporation to not rely on one command computer but on several,
geographically dispersed.
A message to be sent to another computer is divided up into packets, each labelled
with its destination address; the packets are reassembled at the destination
address.
The software that takes care of the packets is mostly Transmission Control
Protocol/Internet Protocol (TCP/IP). TCP does the packeting and reassembling of
the message. The IP part of the protocol handles the addressing, seeing to it that
packets are routed across multiple computers.
The new set of connections, officially established in 1969, was called ARPANet, for
Advanced Research Projects Agency Network.
In 1990, Dr. Tim Berners Lee made getting around the Internet easier by designing a
set of links for one computer to connect to another. He saw the set of links as a
spider's web; hence the name Web. The CERN site at its laboratory in Geneva is
considered the birthplace of the World Wide Web. A link on a web site is easy to
see: it is coloured text called hypertext or an icon or image called a hyperregion. A
mouse click on the link transports the user to the site represented by the link.
As a student, Marc Andreessen, in 1993, led a team that invented the browser,
graphical interface software used to explore the WWW. That first browser was
named Mosaic.
The emergence of the Internet is due to four factors: (1) the universal TCP/IP
standard, (2) the web like ability to link from site to site, (3) the ease of use provided
by the browser's graphical interface, and (4) the growth of personal computers and
their local area networks that could be connected to the Internet.
An Internet user needs a computer with a modem and its related software, an
Internet service provider (ISP), and a browser. An ISP provides the server
computer and the software to connect to the Internet. A browser is the software on
the user's computer that allows the user to access the Internet via the service
provider, using a graphical interface.
If you elect to go directly to an Internet service provider you will need to select one,
arrange to pay the fees, and set up your ISP interaction according to their directions.
As you are installing the browser, you will be asked for information about your ISP,
for which your ISP vendor has prepared you. Once you are set up, you invoke the
browser as you would any software on your computer, and it will begin by dialling the
Internet service provider for you.
When you invoke your browser software, it will dial up the Internet service provider
and, once successfully connected, display the home page of the browser's web site.
The browser shows three parts on the screen, the browser control panel, consisting
of lines of menus and buttons; the browser display window to show the current site;
and a status line at the bottom. The page can be scrolled moved up and down by
using the scroll bar on the right.
Using a mouse permits commands to be issued through a series of menus, a series
of choices normally laid out across the top of the screen. The menus are called pull
down menus because each initial choice, when clicked with a mouse, reveals lower
level choices. Buttons can also invoke commands.
The Uniform Resource Locator (URL) is a string of letters and symbols that is the
unique address of a web page or file on the Internet. A web page URL begins with
the protocol http, which stands for Hypertext Transfer Protocol, the means of
communicating using links. Next comes the domain name, which is the address of
the Internet service provider. The last part of the domain name is called a top-level
domain and represents the purpose of the organization or entity.
A hot list called Bookmarks or Favorites stores favourite sites and their URLS.
In browsers, frames allow a given page to be divided into rectangular sections, each
of which can operate independently of the other.
A plug in is software that enhances the functionality of a browser.
Java, a programming language developed by Sun Microsystems, can be used to
write software that can be used on any machine. Java applets are the small
programs that provide dancing icons, scrolling banners, and the like on web pages.
Methods of moving to other sites from the initial browser page include clicking
categories, typing in a new URL for a desired site, or using a search engine.
A search engine is software that lets a user specify search terms; the search engine
then finds sites that fit those terms. The search can be narrowed by refining the
search criteria.
Another way to narrow a search is to use a mathematical system called Boolean
logic, which uses the operators AND, OR, and NOT.
Search engines vary widely in size, content, and search methodology.
To make a home page on the Web, you need a service provider, software with which
to write it and the ability to use that software, and something to say. A home page
that has value must offer information and at least a passable design.
Web pages were originally written in a language called Hypertext Mark-up
Language, more commonly known as HTML. The HTML code uses a set of tags
that tell your web browser how to format, load, and align text and graphics on your
page. Now easier software simplifies the process of creating HTML code.
Push technology, also called webcasting, refers to software that automatically
sends ("pushes") information from the Internet to a user’s personal computer.
An intranet is a private Internet like network internal to a certain company.
An extranet is a network of two or more intranets.
Numerous solutions to the Internet's sluggish speed have been proposed, including
a cable modem that uses the coaxial television cables already in place without
interrupting normal cable TV reception. The major communication links that tie
servers across wide geographical areas are called the backbone of the Internet.
Widespread use of high-speed home access systems will place even more demands
on the backbone, and that will, in turn, slow everyone's access to the system.
Asymmetric Digital Subscriber Line (ADSL) is digital connection to the Internet
with a faster download speed than upload (most people consume more than they
submit)
Usenet is an informal network of computers that allow the posting and reading of
messages in newsgroups that focus on specific topics. A more informal name is
simply newsgroups. The more than 10,000 newsgroups cover every imaginable
topic. Users can read and contribute messages to the newsgroup. A suggested rule
is that you observe the newsgroup for a while; just reading messages without writing
any an activity called lurking.
Gopher, named for the mascot at the University of Minnesota where it was
developed, lets you "go fer" a certain file through a series of menus that zero in on
your choice. The Gopher software, also accessed by a click on your browser menu,
uses a hierarchical menu structure to organize, search, and deliver information on
the Internet. Veronica and Jughead are software that searches for keywords in
Gopher menus.
Computers on the Internet have a standard way to transfer copies of files, a set of
rules called FTP, for file transfer protocol. Most downloading is done by a method
called anonymous FTP, meaning that a user can be named Anonymous and the
password just the user's e mail address.
Netiquette refers to appropriate behaviour in network communications. Netiquette
rules are published on several sites and in every book about the Internet. Users who
stray may be subjected to flaming, in which angry e mail is directed to someone on
the 'Net who has done something egregious, such as mass advertising.
From: Beekman, George and Quinn, Michael J., Computer Confluence: Tomorrow’s
Technology and You (2006), Pearson Publishing