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About the Internet
The Internet is composed of millions of computers connected in a global network, and increasing in size on a daily basis. Although the technical infrastructure of the Internet is specified by organisations such as the WWW Consortium there is no overall governing body controlling the Internet itself.
| The power of
the Internet lies in the ability to pass information to and fro between your
computer and any other computer that is connected. Since this network includes computers
all over the planet, you have access to a world of information at your fingertips. The
amount of information available, and the speed with which it can be accessed from the
other end of the globe can be truly astounding. When you access the Internet you may be connected to commercial or non-profit organisations, educational institutions, the government or to private individuals. The services available to you include mail, discussion groups, chat rooms, news groups, broadcasting, music, shopping, web cam, file downloads, and of course the entire information content of more than a billion web pages including encyclopaedias, online books, databases, company product support, maps etc....... |
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World Wide Web
The part of the Internet that we use the most is the World Wide Web ('the Web', WWW, W3)
which is distinguished from the rest of the Internet in its use of hyperlinks. Hyperlinks
allow you to click on a part of the web page (either text or images) and be taken to
another web page elsewhere on the network, or to download files, images, video and music
onto your computer. The system is intuitive and requires little training to use, because
there is no need to learn any commands - just click and go.
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Hypertext is
written in a language called HyperText Mark-up Language (HTML), the brainchild of Tim
Berners-Lee. The World Wide Web Consortium co-ordinates the evolution of HTML which is now
in version 4, and of the future web languages such as Dynamic HTML and Extensible Mark-up
Language (XML). The great news about all of these protocols and languages is that you don't need to know anything about them to use the Internet!! However if you want to know more about protocols and standards look at internet.com. |
Accessing the Internet
Your Web browser (usually Microsoft Internet Explorer or Netscape Communicator) is the computer program that does all of the work of accessing and navigating the World Wide Web. Browsers are graphical user interfaces (GUI's) which means you use a mouse to point and click. You will connect to an Internet Service Provider (ISP) using a modem and a telephone line (or possibly via ISDN) and the ISP then allocates you a place on the network.
Although your browser can do all of the basic work of displaying a web page, and downloading files and programs, sometimes it encounters files on the Internet which it cannot handle. These files are run using additional software programs called plug-ins (usually provided free of charge), which extend your browser's capabilities. You do not need to activate the plug-ins yourself, once they are installed, as when your browser encounters a file it cannot handle it automatically activates the appropriate plug-in. You will usually be offered the opportunity to download the plug-in if it is not already installed on your browser - my advice would be to make a note of the plug-in required, and to go to the home site of the plug-in author and download from there. You should only download plug-ins from reputable sites.
One essential plug-in is Adobe Acrobat Reader which reads Portable Document Format (.pdf) files, a common file type for documents on the Internet.
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enhancements which you will notice on your travels are the use of programming languages
such as JavaScript, VBscript, Java, and ActiveX. Although these enhance the multimedia content of the web, and increase the interaction between the users and content, they have caused some security problems. Your browser should prompt you before running an ActiveX control, and in general, unless you trust the site's authors implicitly, you shouldn't run it. |
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E-mail
Electronic mail (E-mail, as distinguished from snail mail) is the exchange of messages,
via computer across the Internet. Your messages arrive in your mailbox, and are picked up
for you by your E-mail client (e.g. Outlook Express), and you can send mail to anyone if
you know their address - mine is raouf@allim.tc.
E-mail will normally arrive within minutes of sending, and you can also send file attachments such as Word documents, Excel files, Powerpoint presentations and HTML files (web pages) and even computer programs. Regrettably the power to send all of these file types has resulted in the power to disseminate E-mail viruses. All of the files I have mentioned above can contain programming code within them. Read the Surfing Safely page if you want further details on protecting your system.
FTP
File Transfer Protocol is the means whereby you can download software (and virtually every
other file type) from the Internet. Your browser can perform the necessary procedures for
you, or if you intend to do a lot of downloading it is worth installing a download manager
such as Go!Zilla (free) to assist you.
This program can dial up to perform
your downloads at scheduled times, disconnecting from the Internet when finished. It will
usually be able to resume a download which has been interrupted (vital if you are
downloading a large file). It will also inform you about the speed of your connection to
the FTP server, and advise on alternative sites where the same file is available.
Searching for FTP files can be done via search engines such as Lycos FAST FTP Search. Alternatively, if you're
brave, you may wish to try the rather old-fashioned Archie
interface.
Discussion, Chat and News Groups
Discussion groups are subject-orientated forums (often academic) conducted via e-mail. The
three main types of mailing list software in use are Listserv, Listproc and Majordomo.
Beware - an active discussion group may generate many e-mail messages per day so don't sign up for too many initially. If you are interested have a look at Liszt which provides a directory of discussion groups together with basic instructions on accessing them. Lsoft is also a good site to look at because it allows you find discussion groups that use a web archive - that way you can actually look at some of the content to help you decide if it is worth joining.
Internet Relay Chat (IRC) is becoming
quite famous as the service in which users from anywhere in the world can type in messages
which are read in real time by the other users. To use IRC, you must have IRC software
(e.g. IRC Gold), but this is freely available from sites such as mycomputer.com.
Sometimes chat rooms are included as a feature of a Web site, where users can log into to
exchange comments and information about the topics addressed on the site. I would
recommend using a pseudonym when you sign up for a chat room (definitely not your e-mail
or real name) as there have been quite a few instances of electronic harassment following
on from chat room sessions.
An enhancement of chat is instant messaging (e.g. via AOL's Instant Messenger) where a
user on the Web can contact another user currently logged in and chat.
Usenet News is a subject-organised
electronic bulletin board system in which users exchange information. Bulletin boards work
by users connecting to the Usenet servers to read the messages (as opposed to receiving
them by e-mail). Newsgroups are moderated by Usenet administrators, who control their own
sites, and decide which newsgroups are allowed on the system. Liszt contains a good directory of Usenet groups.
There is a variety of newsreader software available such as Netscape Communicator's
Messenger utility, or FreeAgent
(free of course). There are comprehensive instructions on configuring a newsreader, and on
finding useful groups at NewsReaders.com.
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Further Reading
The 'Rough Guide to the Internet' is a cheap and authoritative book. Some useful websites to get you started are: -
Internet
Learning Centre
Internet Gurus Central (The Internet home of the
Dummies Guide)
An Internet Guide for the Health
Professional
Glossary
Browsers
Cookies
DNS
Downloading
Essential Software
FAQ
HTML & HTTP
RFC
Search Engines
TCP/IP
URL
World Wide Web
A large glossary of Internet terms is available from Matisse.
Browser
Browsers (e.g. Internet Explorer or Netscape Communicator) are programs, technically known
as client programs, running on your computer, which connect to a World Wide Web server and
ask for a document. The URL designates which server to connect to and which document to
ask for. When the WWW server replies with the contents of the document, the client
(browser) must display it to the user.
Instructions are sent in a specific language, Hypertext Markup Language (HTML), which is a
text file of instructions to your computer on how to display the document page.
DNS
To make Internet addresses easier, there is a system which translates IP address numbers
into names for computers on the Internet. This is the Domain Name System (DNS). The DNS
allows you to type a name such as yahoo.com, rather than a number, to specify a computer.
The Domain Names are held in the directories on local Domain Name Servers and used to
route messages.
Cookies
Cookies are the spawn of the devil according to some people. They are files placed on your
hard disc, usually without your knowledge, by the websites you visit. If you want to have
a look at them check your c:/windows/cookies directory. You can open the
cookies with a text editor but the content may not always be intelligible.
The idea is that when you next log on to the website it can tailor itself to your past profile, and may remember details such as your logon password to avoid the need for you to re-enter them. Unfortunately, three security issues have arisen. The first is whether other sites can read your cookies (with a bit of effort they can) and thereby invade your privacy. Secondly, you don't know what the cookies contain. Thirdly, you may not be happy with third parties saving files onto your hard disc. If you don't want cookies set your Internet browser security options at high.
Downloading
Downloading a web page is as simple as using the File Save As... command in your browser
software. To download images you will need to right click on the image and then save the
graphics file.
Downloading files and programs is also performed by hypertext links on the actual web
page, usually with a set of instructions such as Click here to download.
When downloading files from the Internet it is safest to save them to a particular
directory designated for that purpose, and to virus check the files before opening or
running them.
Essential
Software
The two essential items are a browser (Microsoft Internet Explorer and Netscape are both
free) and a good anti-virus package. Additional programs which will come in handy are:-
WinZip, which allows you to open compressed *.zip files
Adobe Acrobat Reader (free from Adobe) which opens *.pdf files - a common Internet
document format
Programs such as these are usually easily obtained from computer magazine CD's, for a
trial period.
FAQ
FAQ stands for Frequently Asked Questions. If you are using a website, or an online
resource and you need help, then you can usually find a help or a FAQ facility. In
addition there are collections of FAQ's available on the Internet such as The Internet FAQ Consortium.
HTML & HTTP
Browsers (client programs) access servers using the HyperText Transfer Protocol (HTTP).
Servers hold data, such as web pages, written in a language called HyperText Markup
Language (HTML).
Web pages are delivered from WWW servers to clients as HTML, wrapped up in other protocols
such as MIME (Multipurpose Internet Mail Extensions) and conveyed by HTTP.
Request for Comments are the documents whereby the Internet community gets together to decide the technical specification of the Internet. For example, if you want to know exactly how SMTP is specified you would look at RFC 821.
Search
Engine
There is a fuller account of Internet search engines in the Workshop article 'Finding Information on the
Internet'
TCP/IP
TCP/IP is a pair of protocols (set of rules) for sending information from computer to
computer.
The Internet Protocol (IP) divides data into packets, each with a “from” and a
“to” address (e.g.112.25.226.272). Each computer on the Internet has a unique IP
address consisting of four numbers, each less than 256, separated by a full stop.
The IP packets for a single message travel along the Internet via multiple routes. To
ensure data integrity the Transmission Control Protocol (TCP) numbers each packet, and
then makes sure that the packet arrives intact through an error-checking checksum
algorithm. The receiving computer arranges the packets in numerical order and recalculates
a checksum for each. If the checksum is erroneous, the packet is rejected and
retransmission requested.
Another protocol you may come across is File Transfer Protocol (FTP) which is the set of
rules relating to the transfer of files between two computers on the Internet. The main
purpose of this is to download software from other computers. The modern generation of
browsers act as FTP clients, so you do not need a separate program to download files.
URL
Uniform Resource Locators are the addresses on the Internet. They are designed to make it
easier to remember a website address rather than having to use the IP address (which is
just a set of numbers).
The URL takes this format - protocol://host/path/filename
An address which uses Hypertext Transfer Protocol (http) and is on the World Wide Web (www) will have an address which starts as http://www.
The next part of the address designates the host, and allows you to determine the type of website (ac or edu = academic, com = commercial, gov = government, mil - military, net = network, org = organisation) and the country (ac.uk = academic institution in the United Kingdom). The USA, as the home of the web, has no geographical tag.
The final part of the address is the local path to the file.
http://www.shef.ac.uk/~scharr/ir/netting.html
is therefore a world wide web address belonging to Sheffield University, in the UK. On the
local server, there is a directory called ~scharr, with a sub-directory
called ir and a web page called netting.html.
World Wide
Web
The WWW is that section of the Internet which uses Hypertext Transfer Protocol (http),
Hypertext Markup Language (HTML) and Transfer Control Protocol/Internet Protocol (TCP/IP).
The Web is a client-server system. Your web browser software is the client and the remote
computer which stores the data is the server. With the advent of graphical browsers
(notably Internet Explorer and Netscape) the result is a graphical user interface which is
navigated by hypertext links (links embedded in text) and requires very little technical
knowledge to use.
The WWW is managed by The World Wide Web Consortium, funded by major companies such as
Microsoft, AT&T, Adobe Systems, Sun Microsystems etc. The American headquarters of the
consortium is at the Massachusetts Institute of Technology, with INRIA (The French
National Institute for Research in Computer Science) acting as European host, in
collaboration with CERN.
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Raouf Allim
22 Benjamin Road
High Wycombe
Bucks. HP13 6SR
raouf@wycombe.com
27th June 2000