What
is INTERNET?
The Internet is a worldwide collection of computer networks, cooperating with
each other to exchange data using a common software standard. Through telephone
wires and satellite links, Internet users can share information in a variety of
forms. The size, scope and design of the Internet allows users to:
Language of the Internet
The Web, WWW, W3, W3:
The World Wide Web
Web Page: A single Web document. Everything you can
see in your browser window at one time (including what you can see by
scrolling) makes up one Web page.
Browser, Web Browser: The piece of software that
runs on your computer and allows you to view Web pages. The most common
browsers are Netscape and Internet Explorer.
Web Site: A set of Web pages that are logically
connected. They usually have a consistent look and feel, and are all related to
the same theme.
Home Page: The starting, introductory or welcome
page for a Web site. A person's own home page is a Web page that describes all
about them.
Link, Hot Link, Hyper Link: A part of a Web page
that can be clicked to get somewhere else - eg This is a link to the English Online Home Page.
Links usually turn up a different colour and/or underlined in your Web browser.
Broken Link: A link that references a page that no
longer exists. If you click on a broken link you will get some kind of
"Page not found - Error 404" message.
Hypertext: Text that can contain links.
HTML: Stands for HyperText Markup Language. This is
the language that all Web pages are written in.
URL: Stands for Uniform Resource Locator. This is
the address of a Web page - for example http://english.unitecnology.ac.nz/resources/resources/tutorial/introduction/language.html
is the URL of this Web page.
See How a URL works
Webserver, Web Server: A Webserver is a computer
which holds a number of Web pages, and 'serves' them out to computers that
request them. There is nothing very special about the actual computer - it's
just an ordinary computer (though usually a fairly powerful one) running
special software.
Surf: "Surfing the Web" means casually
using the Web - not really having any direction, just clicking the links that
look interesting to find yourself in weird and interesting places.
Cyber: Virtual - not real but existing only in the
context of the Internet.
Cyberspace: A conceptual place that doesn't
actually physically exist - but you can roam around in it, visit places, meet
other people there, chat to them, go shopping ... Cyberspace is a real world
metaphor for the Internet.
Newbie: A person who is new to the Internet, or new
to a particular aspect of the Internet such as a service (IRC, usenet) or a
particular group (a specific mailing list or newsgroup).
Post: When you send a message to a discussion forum,
you're posting. This word can be used as a verb ("I posted a
message") or a noun ("that was a nice post").
FAQ: Stands for Frequently Asked Questions. They
originate from online discussion forums where more experienced users got sick
of answering the same "newbie" questions over and over again. So they
started writing lists of frequently asked questions and their answers so
newbies could refer to those. The concept has grown, and now a FAQ is more
general - designed as an introduction to a certain topic.
Snail Mail: Traditional mail using paper, pen,
envelope and stamp.
Remote: Not on your own computer or on a computer
directly connected with yours, but far away out in the Internet somewhere.
Local: On your own computer, or on a computer
connected closely with yours (a local network).
Download: Download a file means transferring that
file from a remote computer to your own computer. Technically, you are
downloading a Web page (and all the elements, such as pictures contained on it)
every time you view it, but the word is usually resevered to describe saving a
file permanently on your own computer.
Shareware: Software that you can use for free on a
trial basis. It can often be downloaded from the Web.
ISP: Stands for Internet Service Provider. They are
companies who provide you with Internet access (for example Xtra
or Ihug). Usually you use your telephone
connected to a modem to dial up and connect your computer to your ISP.
Interactive: Refers to any program which lets the
user make decisions that affect the way the program operates in some way. It
could be as simple as clicking a hypertext link, or more complicated like
answering a quiz question and getting feedback.
Bandwidth: It has a technical definition, but it is
mostly used to describe how much data you can fit through a single connection
at a time, and is related to how fast your Internet connection is.
E-Anything: You can prefix the letter E to any activity
to make it mean doing that activity over the Internet. "E-learning"
and "E-commerce" are common examples of this. This practice has
evolved from the word "Email" (in which the E stands for Electronic).
"E" seems to have taken over from "Cyber" as the prefix-du-jour.
There are several different Web Browsers available. However, 90%
of the Internet population uses one of the two most popular browsers - Netscape
Navigator or Microsoft Internet Explorer. These two browsers are in fierce
competition (in what's commonly called the "browser wars").
However their functionality is very similar - in fact all browsers share many
of the same features.
Hyperlinks: The most basic navigational element in a Web browser is a
link. A link is a piece of text that takes you to another Web page (or
somewhere else within the current Web page) when you click on it. Links are
usually differentiated from the surrounding text by being a different colour
and underlined.
This is what a link looks like
in your Web browser.
Links that you have visited before will usually have a different colour to
those that you have not been to yet.
This is a link you have visited
before.
You can define the default appearance of links in your browser's
"preferences". Some pages will keep this default appearance, but
others may define their own link colours.
Links may also be in the form of images. There is no clear way to tell whether
an image is a link (sometimes there is a blue border around the picture). Most
good Web sites will make their picture look like they should be clicked.
This image is also a link to the English On-Line home page.
When you move your cursor over a link, the cursor shape will usually change
into a hand. The destination of the link will also turn up in the status bar -
the bar at the bottom of the browser.
Run your cursor over this link
and you will see the cursor change to a hand and the status bar will show the
address.
Location/Address Box: Another way to get to a Web page is to type its URL straight into
the location box/address box.
To do this you have to know the URL. You can get them from external sources (eg
advertisements, articles in magazines, books) - or you can copy and paste them
from places on your computer (eg email messages). If you type a link into your
Web browser you have to make sure you type it in exactly as it is written. One
small mistake (like using the wrong case) and the browser will not be able to
find the page that you want. Once you have typed (or pasted) the URL, you need
to press the "Enter" key to signal to your browser to load the page.
Back Button: The back button is an important navigational tool. It takes
you back to the last page you had open.
Go Menu: The Go menu is like the back button, but it has a list of all
the pages you have visited. You can use this to get back to a page you have
previously visited. It saves you having to repeatedly press the back button. In
Netscape, use the "Go" menu on the menu bar. In Internet Explorer the
menu is on the down arrow next to the Back button.
Bookmarks/Favorites: A bookmark is a place holder of a Web page - so you
can easily find the page again when you want it. To define a bookmark in
Netscape, select "Add Bookmark" from the "Bookmarks" menu.
In Internet Explorer bookmarks are called "Favorites" - select
"Add to Favorites" from the "Favorites" menu. When you want
to go back to a page you have bookmarked, just select the name of the page from
the Bookmarks/Favorites menu. After a while you will find that your bookmarks
are overflowing, and it will get difficult to find what you want. When this
happens you know that it's time to start filing your bookmarks into folders.
You can do this by choosing 'Go to bookmarks' from the Bookmarks menu (or
"Organize Favorites" from the "Favorites" menu). This will
take you into a window where you can add folders, and then file your bookmarks
by dragging them to the folder where you want them to live.
Images: Images are what make Web pages look attractive, but they are
also what makes some Web pages take a long time to load. If you are on a slow
connection you might not want to waste your time by downloading lots of images.
You can avoid this by turning the images off, so they are no longer loaded
automatically. You need to turn off "Auto Load Images" or "Show
Pictures" in your browsers' preferences/options. If you do this you will
soon find out that you are missing lots of information, and that the pages will
look a lot duller. If you decide you do want to see a particular image, you can
load it by clicking the right mouse button (right clicking) on the placeholder
image, and selecting "Load Image" or "Show Image" from the
pop up menu. (On a Mac, click and hold the mouse button)
You can save images to your computer (just remember about copyright
laws!) by right clicking (or clicking and holding on a mac)
on the image you want to save and selecting "Save Image As..." or
"Save Picture As" from the pop up menu.
If you see this or this on a Web page, it means that the image couldn't be
found (usually caused by a mistake by the person who wrote the Web page).
Home Button: The Home button (in the button bar at the top of the
browser) will take you back to your "home" page. You can define the
address of your home page in your browser's preferences (or "Internet
Options"). You can make it any page you want - it's most useful if you
make it a page that you often use as a starting point - English Online for instance.
Reload: The Reload button will load the whole page again from the Web
site. This is useful if:
New Browser Window: By selecting "New Web Browser" or
"New...Window" from the "File" menu you can open a new
browser window. This allows you to keep one page intact while you go off and
find another page. For instance you might want to keep a page of search results
open in one browser window while you use another window to check out the result
pages. If you decide the page is not quite what you want, you can close the
browser window and return to the list of search results without having to
reload it (a good way of doing that is to 'right-click' or 'click-and-hold' a
link and choose "Open Link in New Window" from the popup menu).
Sometimes you might want to get a file from the Web and save it
on your own computer. For example you might want to open a Word document in MS
Word, or download some software so you can run it on your computer.
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To
download a file:
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You may find that just clicking the link will download the file
for you, or it may automatically run the software that will open the file. You
may be presented with a dialogue box that asks if you want to save the file, or
open it using the appropriate software. Remember that files you download may contain viruses,
so it's safest to save them to your computer first and check them for viruses
before you run them.
Zip Files: You may often be confronted with the choice of downloading
zip (or zipped) files from the Web. These are files that have been compressed
to make the file size smaller to make them quicker to download. Sometimes it's
a single file that has been zipped, other times several files have been zipped
into a single file. After you have downloaded the file, you need to unzip it
using special software. If you have such software installed on your computer,
you will probably find that just double clicking the file will run the
software. You usually have to choose a destination folder which is where the
file (or files) will be put once they have been 'expanded' out into their full
size.
A form is a part of a Web page into which you can enter
information by typing in a text box, choosing an option from a menu or clicking
on a checkbox. Here are the common form elements:
This is a text box (practise by typing some text in it).
This is a menu (practice by choosing one of the options).
This is checkbox (practice by checking and unchecking the box).
I agree
The information you enter into the form doesn't go anywhere until you submit
the form. To submit the form you need to press a button which will be located
at the bottom of the form, and will usually look something like this: (practice
by pressing the button - it won't do anything though!). You only need to press
the "Submit" button once. It might take a while for your browser to
do anything (it needs to 'think' a bit first!), but don't keep pushing the
button - your form will get submitted multiple times if you do.
Once you press the "Submit" button your form will usually be
processed by a program running on a Web server. This
program will take the contents of the form and do something with them (for
example email them to the relevant person).
The Web is a very big and very disorganised place. Just about
any information you would ever want to know (and a whole lot more that you
wouldn't) exists on the Web somewhere. But finding it is another story.
The reason for this is that it was never designed as a global information
retrieval system, hence there is no central place monitoring where or how
information is stored. The added complication of hypertext makes
it very easy to lose your focus and get lost.
Trailblazer Pages (Links Pages)
These are lists of links to other sites related to a particular subject. The
most useful trailblazer pages have links divided into categories and
descriptions of why each site is useful. An example is the English Online links page.
Trailblazer pages are often constructed by enthusiastic amateurs. Some
librarians are creating trailblazer pages to help people find information, eg. Children's Literature Page at the University of Calgary
Trailblazer pages can be very useful in your Web searching. You will often find
links to pages that don't show up in search engines or directories. However, it
can be frustrating to jump from one trailblazer page to another without finding
any pages with actual content!
Portal Sites
These are sites aim to be an Internet 'one-stop-shop', either to the whole
Internet, or for for one particular broad subject (eg. Education). As well as
link directories and search engines they might offer a range of other services
such as discussion forums, online shopping malls and news reports. They can be
quite useful, especially for new users to get orientated to what kinds of
things the Internet can offer them. No portal can cover the entire Internet
though, so eventually you might find their range of subjects limiting and
prefer to go on a wider hunt for the information you require.
Subject Trees (Directories)
A subject tree is a broad list of categories that branch off into
sub-categories, such as that found in Yahoo or Te Puna. These are not organised by
librarians so the subject classification doesn't conform to any established
system. They aren't in any way complete - pages are usually only added to the
directory when the writer of the page requests is.
Search Engines
These are computer programs that 'whiz around' the Internet to find documents
that contain key words which you type in. Search engines have different ways of
searching which means that they will return different results and may be more
or less successful for different searches.
They have wonderful names like Alta Vista,
Infoseek, Webcrawler,
Excite,
Hotbot,
Google,
Dogpile and Lycos.
Limitations of Search Engines
Directories or Trailblazer pages are usually more successful
when you are searching for a site with some general information about a topic,
for instance:
Search engines are more useful when looking for very specific or
obscure information, for instance:
Sometimes you will find the information you want almost
immediately - other times you will be led on a wild goose chase through page
after page of links. Don't give up too easily though, persistence usually pays
off.
The name hypertext, or hypermedia, has been applied to networks
of nodes (also called articles, documents, files, cards, pages, frames,
screens) containing information (in text, graphics, video, sound, and so on)
that are connected by links (also called pointers, cross-references,
citations). Hypertext is more commonly applied to text-only applications
whereas hypermedia is used to convey the inclusion of other media, especially
sound and video.
The intrigue of hypertext is that it extends traditional linear text with the
opportunity for jumping to multiple related articles. Convenient backtracking,
clickable indexes and tables of contents, string searching, bookmarks, and
other navigation tools profoundly alter the reader's experience....hypertext
authors need to choose appropriate projects, to organize their articles
suitably, and to adjust their writing style to make the best use of this new
medium.
The largest hypermedia experiment of all time is happening right in front of
our eyes. Since the advent of the World Wide Web, many people have been able to
experience the relatedness of the internet, with its accompanying problems of
disorientation.
In a review of hypermedia-based learning, Ayersman [1] discussed four
strands of research into learning and hypermedia: research based on perceptions
or attitudes about hypermedia; research based on individual differences or
learning styles; research based on system analyses (which examined the most
effective ways to structure hypermedia); and, research based on performance
which ranged from use of pre-made software to the construction of one's own
software.
His conclusions:
As a counterbalance to this optimistic review of the potential
of hypermedia for learning, McKnight, Dillon & Richardson [2] provide a
different viewpoint. After reviewing various studies on learning and
hypermedia, they conclude:
Shneiderman [3] provides the
following guidelines for creating hypertexts:
Reduce cognitive load by minimizing the burden on the user's
short term memory. You can do this by providing on-screen prompts such as icons
or menus rather than requiring the user to memorize terms or codes. The goal is
to enable users to concentrate on the contents while the computer vanishes.
To help you understand how the Internet works, we'll look at the
things that happen when you do a typical Internet operation — pointing a
browser at the front page of this document at its home on the Web at the Linux
Documentation Project. This document iswhich means it lives in the file HOWTO/Unix-and-Internet-Fundamentals-HOWTO/index.html
under the World Wide Web export directory of the host www.tldp.org.
The first thing your browser has to do is to establish a network
connection to the machine where the document lives. To do that, it first has to
find the network location of the host www.tldp.org (‘host’ is short for
‘host machine’ or ‘network host'; www.tldp.org is a typical hostname).
The corresponding location is actually a number called an IP address
(we'll explain the ‘IP’ part of this term later).
To do this, your browser queries a program called a name server. The
name server may live on your machine, but it's more likely to run on a service
machine that yours talks to. When you sign up with an ISP, part of your setup
procedure will almost certainly involve telling your Internet software the IP
address of a nameserver on the ISP's network.
The name servers on different machines talk to each other, exchanging and
keeping up to date all the information needed to resolve hostnames (map them to
IP addresses). Your nameserver may query three or four different sites across
the network in the process of resolving www.tldp.org, but this usually happens
very quickly (as in less than a second). We'll look at how nameservers detail
in the next section.
The nameserver will tell your browser that www.tldp.org's IP address is
152.19.254.81; knowing this, your machine will be able to exchange bits with
www.tldp.org directly.
The whole network of programs and databases that cooperates to
translate hostnames to IP addresses is called ‘DNS’ (Domain Name System). When
you see references to a ‘DNS server’, that means what we just called a
nameserver. Now I'll explain how the overall system works.
Internet hostnames are composed of parts separated by dots. A domain is
a collection of machines that share a common name suffix. Domains can live
inside other domains. For example, the machine www.tldp.org lives in the
.tldp.org subdomain of the .org domain.
Each domain is defined by an authoritative name server that knows the IP
addresses of the other machines in the domain. The authoritative (or ‘primary')
name server may have backups in case it goes down; if you see references to a secondary
name server or (‘secondary DNS') it's talking about one of those. These
secondaries typically refresh their information from their primaries every few
hours, so a change made to the hostname-to-IP mapping on the primary will
automatically be propagated.
Now here's the important part. The nameservers for a domain do not have
to know the locations of all the machines in other domains (including their own
subdomains); they only have to know the location of the nameservers. In our
example, the authoritative name server for the .org domain knows the IP address
of the nameserver for .tldp.org but not the address of all the other
machines in .tldp.org.
The domains in the DNS system are arranged like a big inverted tree. At the top
are the root servers. Everybody knows the IP addresses of the root servers;
they're wired into your DNS software. The root servers know the IP addresses of
the nameservers for the top-level domains like .com and .org, but not the
addresses of machines inside those domains. Each top-level domain server knows
where the nameservers for the domains directly beneath it are, and so forth.
DNS is carefully designed so that each machine can get away with the minimum
amount of knowledge it needs to have about the shape of the tree, and local
changes to subtrees can be made simply by changing one authoritative server's
database of name-to-IP-address mappings.
When you query for the IP address of www.tldp.org, what actually happens is
this: First, your nameserver asks a root server to tell it where it can find a
nameserver for .org. Once it knows that, it then asks the .org server to tell
it the IP address of a .tldp.org nameserver. Once it has that, it asks the
.tldp.org nameserver to tell it the address of the host www.tldp.org.
Most of the time, your nameserver doesn't actually have to work that hard.
Nameservers do a lot of cacheing; when yours resolves a hostname, it keeps the
association with the resulting IP address around in memory for a while. This is
why, when you surf to a new website, you'll usually only see a message from
your browser about "Looking up" the host for the first page you
fetch. Eventually the name-to-address mapping expires and your DNS has to
re-query — this is important so you don't have invalid information hanging
around forever when a hostname changes addresses. Your cached IP address for a
site is also thrown out if the host is unreachable.
What the browser wants to do is send a command to the Web server
on www.tldp.org that looks like this:
Here's how that happens. The command is made into a packet, a block of
bits like a telegram that is wrapped with three important things; the source
address (the IP address of your machine), the destination address
(152.19.254.81), and a service number or port number (80, in this
case) that indicates that it's a World Wide Web request.
Your machine then ships the packet down the wire (your connection to your ISP,
or local network) until it gets to a specialized machine called a router.
The router has a map of the Internet in its memory — not always a complete one,
but one that completely describes your network neighborhood and knows how to
get to the routers for other neighborhoods on the Internet.
Your packet may pass through several routers on the way to its destination.
Routers are smart. They watch how long it takes for other routers to
acknowledge having received a packet. They also use that information to direct
traffic over fast links. They use it to notice when another router (or a cable)
have dropped off the network, and compensate if possible by finding another
route.
There's an urban legend that the Internet was designed to survive nuclear war.
This is not true, but the Internet's design is extremely good at getting
reliable performance out of flaky hardware in an uncertain world. This is directly
due to the fact that its intelligence is distributed through thousands of
routers rather than concentrated in a few massive and vulnerable switches (like
the phone network). This means that failures tend to be well localized and the
network can route around them.
Once your packet gets to its destination machine, that machine uses the service
number to feed the packet to the web server. The web server can tell where to
reply to by looking at the command packet's source IP address. When the web
server returns this document, it will be broken up into a number of packets.
The size of the packets will vary according to the transmission media in the
network and the type of service.
To understand how multiple-packet transmissions are handled, you
need to know that the Internet actually uses two protocols, stacked one on top
of the other.
The lower level, IP (Internet Protocol), is responsible for labeling
individual packets with the source address and destination address of two
computers exchanging information over a network. For example, when you access
http://www.tldp.org, the packets you send will have your computer's IP address,
such as 192.168.1.101, and the IP address of the www.tldp.org computer,
152.2.210.81. These addresses work in much the same way that your home address
works when someone sends you a letter. The post office can read the address and
determine where you are and how best to route the letter to you, much like a
router does for Internet traffic.
The upper level, TCP (Transmission Control Protocol), gives you
reliability. When two machines negotiate a TCP connection (which they do using
IP), the receiver knows to send acknowledgements of the packets it sees back to
the sender. If the sender doesn't see an acknowledgement for a packet within
some timeout period, it resends that packet. Furthermore, the sender gives each
TCP packet a sequence number, which the receiver can use to reassemble packets
in case they show up out of order. (This can easily happen if network links go
up or down during a connection.)
TCP/IP packets also contain a checksum to enable detection of data corrupted by
bad links. (The checksum is computed from the rest of the packet in such a way
that if either the rest of the packet or the checksum is corrupted, redoing the
computation and comparing is very likely to indicate an error.) So, from the
point of view of anyone using TCP/IP and nameservers, it looks like a reliable
way to pass streams of bytes between hostname/service-number pairs. People who
write network protocols almost never have to think about all the packetizing,
packet reassembly, error checking, checksumming, and retransmission that goes
on below that level.
Now let's get back to our example. Web browsers and servers
speak an application protocol that runs on top of TCP/IP, using it
simply as a way to pass strings of bytes back and forth. This protocol is
called HTTP (Hyper-Text Transfer Protocol) and we've already seen one
command in it — the GET shown above.
When the GET command goes to www.tldp.org's webserver with service number 80,
it will be dispatched to a server daemon listening on port 80. Most
Internet services are implemented by server daemons that do nothing but wait on
ports, watching for and executing incoming commands.
If the design of the Internet has one overall rule, it's that all the parts
should be as simple and human-accessible as possible. HTTP, and its relatives
(like the Simple Mail Transfer Protocol, SMTP, that is used to move electronic
mail between hosts) tend to use simple printable-text commands that end with a
carriage-return/line feed.
Reason Why People Uses the INTERNET
This is marginally inefficient; in some circumstances you could get more speed
by using a tightly-coded binary protocol. But experience has shown that the
benefits of having commands be easy for human beings to describe and understand
outweigh any marginal gain in efficiency that you might get at the cost of
making things tricky and opaque.
Therefore, what the server daemon ships back to you via TCP/IP is also text.
The beginning of the response will look something like this (a few headers have
been suppressed):
Think about the ways that you advertise to get more business. You
probably have business cards, letterhead, Yellow Pages advertisements,
newspaper ads, etc. All of these have your name, address, and phone number on
them, right? Well, why not give potential customers another way of contacting
you - through email? Or how about giving them another method for getting
information about what your company is and what it does - through a website?
Approximately 150 million people worldwide have access to the Internet. No
matter what your business is, you simply can't ignore that many people. To be a
part of this growing community and show that you are interested and capable of
serving these people, you need to be on the World Wide Web. You know your
competitors will.
What if you could pass out your business card to thousands, possibly millions
of potential clients and partners? You can, 24 hours a day, on the Internet.
You can send people information in an instant through email, instead of waiting
days for mail to be sent to them. Even if someone is on the other side of the
country, or the other side of the world, you can communicate with them
effectively and efficiently just by having a website and email address.
Think about all of the things you can convey to your customers, without even
talking to them or mailing them info. What do you do? What are your hours?
How can someone contact you? What methods of payment do you take? Where are you
located? If you could keep your customers informed of every reason why
they should do business with you, don't you think you could do more business?
You can on the Internet.
With Carrie's Creations Website Design, you are not limited to a static site
that cannot keep a visitor's attention. Why not have a dynamic website that
your customers will tell their friends about... a site that uses cutting-edge
technology. Whether you are looking for an elegant yet simple one-page site or
an interactive presentation using Shockwave or streaming audio and video,
Carrie's Creations will design a website that will meet your needs and exceed
your expectations. If you are a retail business, you can have an online
shopping cart to sell products, with a secure server for credit card
transactions. All this can be yours at a very competitive cost.
Internet: History
In tracing the history of the Internet, it is useful to begin at its conceptual
foundation. The Internet is an example of a type of network called a packet-switched
network. These networks differ from telephone networks in a number of
important ways. Technological differences aside, one significant difference
between these networks is that packet-switched networks are designed to support
a wide variety of applications, whereas the telephone network was designed to
support one application (voice communications) optimally, though a few other
applications are possible as well.
Intellectually, the origin of the Internet can be traced back to the early to
mid-1960s, when Leonard Kleinrock, Joseph Licklider, Paul Baran, Lawrence
Rogers, and others developed the ideas and theories underpinning these general
purpose packet-switched networks. By 1967 some early experiments with using
packet-switching technologies were taking place at the National Physical
Laboratory in England. In 1969 the U.S. Defense Department's Advanced Research
Projects Agency (ARPA) funded a larger scale network project. The initial
network interconnected the University of California-Los Angeles, Stanford
Research Institute, University of California-Santa Barbara, and the University
of Utah. Researchers at these institutions began to develop the software needed
to make the network operate, and, by the end of 1969, were able to send some
data packets over the network. But the capabilities were very rudimentary, and
much work remained to be done.
In the early 1970s, the network software, which caused the computers in the
network nodes to perform basic packet-switching functions, was standardized
into the Network Control Protocol (NCP), and new sites were added. By
1971 there were 15 locations (nodes) on the network, serving 23 host computers.
As the basic network software was being developed, so were the (initially
rudimentary) applications that would use the network. One of the early
applications was electronic mail; in fact, the use of the now standard
"@" sign for e-mail was begun in 1972.
While the primary focus had remained on constructing packet-switched networks,
Robert Kahn posed the "Internet problem"—namely how to get autonomous
networks to exchange information—in 1972. The idea that a network could support
(and even encourage) heterogeneity would ultimately be of great importance to
the success of the Internet over technologies that were unable to provide this
support easily.
The network continued to grow as well. By 1973, the first international site
was introduced, which was to the University College in London via Norway; in
addition, the ARPANET supported approximately 2,000 users. The genesis of
today's computer environment was also being developed at this time, with the
basic theory of the Ethernet local area network (LAN), which is
today the dominant local networking system, and the modern computer
workstation. The Alto workstation was developed at Xerox's Palo Alto
Research Center (PARC) and had a graphical user interface (GUI) with
icons and a mouse. While nobody could predict the extent to which these
technologies would come to dominate computing, they, together with Kahn's
statement of the Internet problem, would combine to form the Internet as it is
known today.
By 1974, enough had been learned about techniques for implementing
packet-switching technology that a second generation protocol and the
associated network software could be proposed. This was called the Transmission
Control Protocol (TCP). This proposal included what users today understand
as TCP and IP. The initial tests of TCP did not take place until 1975. By this
time, commercial packet-switching services (though not based on NCP or TCP) had
come into being, and the possibilities that these networks afforded began to be
imagined. In fact, in 1976 Queen Elizabeth II sent an e-mail.
TCP continued to be developed during this time, and, in 1978, TCP and IP were
divided into separate components so that their functions could be improved.
Other notable events of the late 1970s included the development of the first
Multi-User Domain (MUD), the proliferation of mailing lists, and the emergence of
emoticons. By this time the utility of electronic mail was more widely
recognized. To extend this capability beyond the domain of the ARPANET, new
networks were formed. They included CSNET, BITNET (because it is time network),
and FIDONET. Each of these networks used different network protocols, had
different organizational forms, and reached different users. CSNET was targeted
at university computer science departments and received funding from the
National Science Foundation. BITNET was targeted at a more diverse academic
audience, and was organized cooperatively so that each member paid for its
connection to the nearest node, and agreed to transport others' traffic.
FIDONET was built upon message forwarding over dialup telephone lines and was
generally used by home computer users and hobbyists.
Though Kahn had articulated the Internet problem in 1972, and work on TCP had
begun in 1978, it was not until 1982 that the conversion from NCP to TCP/IP
took place (the crossover took place on January 1, 1983), and the notion of the
Internet was first defined as a set of interconnected networks. The conversion
to TCP/IP was bolstered when the U.S. Department of Defense declared TCP/IP to
be the standard for its computer networking applications. Other events of the
early and mid 1980s include:
By the late 1980s, commercial interest in computer networking
was growing. This was prohibited by the NSF's Acceptable Use Policy, so limited
private networks (such as UUNET) began emerging. This was also the time of the
first "bug," the Internet worm that disrupted many of the hosts attached
to the network. The worm incident prompted the establishment of the Computer
Emergency Response Team (CERT) at Carnegie Mellon University. By the end of the
decade, there were more than 100,000 computers attached to the network.
It was also during this time that the utility of the Internet as an information
resource began to emerge. Many researchers made their reports available via
anonymous File Transfer Protocol (FTP). However, the problem of locating
reports of interest brought the techniques of information storage and retrieval
from the library and information science community to the Internet. The first
tool for locating reports was Archie. Released in 1990, Archie was an
index and search tool for anonymous FTP sites that researchers could use to
locate information more efficiently. The next step was more interactive
information content, which was embodied in Gopher for textual
information, released in 1991; soon thereafter, an index of Gopher sites,
called Veronica, was released in 1992. As useful as Gopher was, it was
still limited. The hypertext-based WorldWideWeb (WWW) was initially released in
1991 by Tim Berners-Lee, which provided a framework for integrated information
content. Despite this, no compelling interface for the web existed until Mosaic
was released in 1993. Even without the web, the number of computers connected
to the Internet increased by an order of magnitude (to 1 million) in only three
years.
The promise of the Internet was not lost on commercial users. In the early
1990s, private network service providers (for example, PSINET) emerged to carry
commercial traffic. These service providers created the Commercial Internet
Exchange (CIX) to exchange traffic among themselves so that a user of any
commercial network could contact a user of any other commercial network. The
NSF came under increasing pressure to privatize the NSFNET. This was finally
accomplished in 1994. The NSF continued to support next generation Internet
research through projects such as the very high-speed Backbone Network Service
(vBNS). With the removal of the restrictive Acceptable Use Policy of the NSF,
commercial Internet ventures flourished with the introduction of streaming
audio in 1995, Internet banking, and the like.
The emergence of the Internet placed substantial pressure on existing legal
structures as well. The Electronic Frontier Foundation (EFF) was founded in
1990 by Mitchell Kapor to explore these questions. As commercial interests
became significant (following the Internet's privatization), issues such as
trademarks, cryptography, copyright, and privacy became important legal as well
as public policy issues. While there has been substantial evolution in this
regard over the last decade, substantial open questions remain.
The first World Wide Web server, currently in the CERN museum, labeled
"This machine is a server. DO NOT POWER DOWN!!"
The history of the Internet dates back to the early development of communication networks. The idea of a computer network intended to allow general
communication among users of various computers has
developed through a large number of stages. The melting pot of developments
brought together the network of networks[1]
that we know as the Internet. This included both
technological developments and the merging together of existing network infrastructure and telecommunication systems.
The earliest versions of these ideas appeared in the late 1950s. Practical
implementations of the concepts began during the late 1960s and 1970s. By the
1980s, technologies we now recognize as the basis of the modern Internet began
to spread over the globe. In the 1990s the introduction of the World Wide Web (WWW) saw its use become
commonplace.
The infrastructure of the Internet spread across the globe to create the world
wide network of computers we know today. It spread throughout the Western
nations and then begged a penetration into the developing countries, thus
creating both unprecedented worldwide access to information and communications
and a digital divide in access to this new
infrastructure. The Internet went on to fundamentally alter and affect the
economy of the world, including the economic implications of the dot-com bubble and offshore outsourcing of White-collar workers.
Prior to the widespread inter-networking that led to the
Internet, most communication networks were limited by their nature to only
allow communications between the stations on the network. Some networks had gateways or bridges between them, but these bridges
were often limited or built specifically for a single use. One prevalent
computer networking method was based on the central mainframe method, simply allowing its
terminals to be connected via long leased lines.
This method was used in the 1950s by Project RAND to support researchers such
as Herbert Simon, in Pittsburgh, Pennsylvania, when
collaborating across the continent with researchers in Santa Monica, California, on automated theorem proving and artificial intelligence.
A fundamental pioneer in the call for a global network, J.C.R. Licklider, articulated the idea in
his January 1960 paper, Man-Computer Symbiosis.
"a network of such [computers], connected to one another by wide-band
communication lines" which provided "the functions of present-day
libraries together with anticipated advances in information storage and
retrieval and [other] symbiotic functions. " -- J.C.R. Licklider [2]
In October 1964, Licklider was appointed head of the United States Department of
Defense's DARPA information processing office, and
formed an informal group within DARPA to further computer research. As part of
the information processing office's role, three network terminals had been
installed. One for System Development Corporation in Santa Monica, one for Project Genie at the University of California,
Berkeley and one for the Multics project at the Massachusetts Institute of
Technology (MIT). Licklider's need for inter-networking would be
made evident by the problems this caused.
"For each of these three terminals, I had three different sets of user
commands. So if I was talking online with someone at S.D.C. and I wanted to
talk to someone I knew at Berkeley or M.I.T. about this, I had to get up from
the S.D.C. terminal, go over and log into the other terminal and get in touch
with them.
I said, oh, man, it's obvious what to do: If you have these three terminals,
there ought to be one terminal that goes anywhere you want to go where you have
interactive computing. That idea is the ARPAnet." -- Robert W. Taylor,
co-writer with Licklider of "The Computer as a Communications
Device", in an interview with the New York Times [3]
At the core of the inter-networking problem lay the issue
of connecting separate physical networks to form one logical network. During
the 1960s, several groups worked on and implemented packet switching. Donald Davies (NPL), Paul Baran (RAND
Corporation) and Leonard Kleinrock
(MIT) are credited with the simultaneous invention. The notion that the
Internet was developed to survive a nuclear attack has its roots in the early
theories developed by RAND. Baran's research had approached packet switching
from studies of decentralisation to avoid combat damage compromising the entire
network. [4]
Promoted
to the head of the information processing office at ARPA, Robert
Taylor intended to realize Licklider's ideas of an interconnected networking
system. Bringing in Larry Roberts
from MIT, he initiated a project to build such a network. The first ARPANET
link was established between the University of California, Los
Angeles and the Stanford Research Institute on 21 November
1969. By 5 December 1969, a 4-node network was connected by adding the University of Utah and the University of California, Santa
Barbara. Building on ideas developed in ALOHAnet, the ARPANET started in 1972 and
was growing rapidly by 1981. The number of hosts had grown to 213, with a new
host being added approximately every twenty days. [6] [7]
ARPANET became the technical core of what would become the Internet, and a
primary tool in developing the technologies used. ARPANET development was
centered around the Request for Comments
(RFC) process, still used today for proposing and distributing Internet
Protocols and Systems. RFC 1, entitled "Host Software",
was written by Steve Crocker from the University of California, Los
Angeles, and published on April 7, 1969.
International collaborations on ARPANET were sparse. For various political
reasons, European developers were concerned with developing the X.25
networks. Notable exceptions were the Norwegian Seismic Array (NORSAR) in 1972,
followed in 1973 by Sweden with satellite links to the Tanum Earth Station and University College London. [1]
These early years were documented in the 1972 film Computer Networks: The Heralds
of Resource Sharing.
See main articles at X.25, Bulletin board system and FidoNet.
Following on from DARPA's research, packet switching networks were developed by
the International Telecommunication
Union (ITU) in the form of X.25 networks. In 1974, X.25 formed
the basis for the SERCnet network between British academic and research
sites, which later became JANET. The
initial ITU Standard on X.25 was approved in March 1976.
Unlike ARPAnet, X.25 was also commonly available for business use. X.25 would
be used for the first dial-in public access networks, such as Compuserve and Tymnet. In 1979, CompuServe became the
first service to offer electronic mail capabilities and technical
support to personal computer users. The company broke
new ground again in 1980 as the first to offer real-time chat with its CB Simulator. There were also the America Online (AOL) and Prodigy dial in networks and many bulletin board system (BBS) networks such
as The WELL and FidoNet. FidoNet in particular was popular
amongst hobbyist computer users, many of them hackers and amateur radio operators.
See main articles at UUCP and Usenet.
In 1979, two students at Duke University, Tom
Truscott and Jim Ellis, came up with the idea of using
simple Bourne shell scripts to transfer news and
messages on a serial line with nearby University of North Carolina at
Chapel Hill. Following public release of the software, the mesh
of UUCP hosts forwarding on the Usenet news rapidly expanded. UUCPnet, as it
would later be named, also created gateways and links between FidoNet and
dial-up BBS hosts. UUCP networks spread quickly due to the lower costs
involved, and ability to use existing leased lines, X.25
links or even ARPANET connections. By 1983 the number of
UUCP hosts had grown to 550, nearly doubling to 940 in 1984.
With so many different network methods, something needed to
unify them. Robert E. Kahn of DARPA and ARPANET recruited
Vint Cerf of Stanford University to work with him on
the problem. By 1973, they had soon worked out a fundamental reformulation,
where the differences between network protocols were hidden by using a common internetwork protocol, and instead of the
network being responsible for reliability, as in the ARPANET, the hosts became
responsible. Cerf credits Hubert Zimmerman
and Louis Pouzin (designer of the CYCLADES network) with important work on
this design. [9]
With the role of the network reduced to the bare minimum, it became possible to
join almost any networks together, no matter what their characteristics were, thereby
solving Kahn's initial problem. DARPA agreed to fund development of prototype
software, and after several years of work, the first somewhat crude
demonstration of what had by then become TCP/IP occurred in July 1977. This new
method quickly spread across the networks, and on January 1, 1983, TCP/IP
protocols became the only approved protocol on the ARPANET, replacing the
earlier NCP protocol. [10]
After the ARPANET had been up and running for several years,
ARPA looked for another agency to hand off the network to; ARPA's primary
business was funding cutting-edge research and development, not running a
communications utility. Eventually, in July 1975, the network had been turned
over to the Defense Communications Agency,
also part of the Department of Defense.
In 1983, the U.S. military portion of the ARPANET was
broken off as a separate network, the MILNET.
The networks based around the ARPANET were government funded and therefore
restricted to noncommercial uses such as research; unrelated commercial use was
strictly forbidden. This initially restricted connections to military sites and universities. During the 1980s, the
connections expanded to more educational institutions, and even to a growing
number of companies such as Digital Equipment Corporation and Hewlett-Packard, which were participating
in research projects or providing services to those who were.
Another branch of the U.S. government,
the National Science Foundation
(NSF), became heavily involved in internet research and started development of
a successor to ARPANET. In 1984 this resulted in the first Wide Area Network designed specifically to
use TCP/IP. This grew into the NSFNet backbone, established in 1986, and intended
to connect and provide access to a number of supercomputing centers established by the
NSF.
It was around the time when ARPANET began to merge with NSFNet,
that the term Internet originated,[11]
with "an internet" meaning any network using TCP/IP. "The
Internet" came to mean a global and large network using TCP/IP, which at
the time meant NSFNet and ARPANET. Previously "internet" and
"internetwork" had been used interchangeably, and "internet
protocol" had been used to refer to other networking systems such as Xerox Network Services.[12]
As interest in wide spread networking grew and new applications for it arrived,
the Internet's technologies spread throughout the rest of the world. TCP/IP's
network-agnostic approach meant that it was easy to use any existing network
infrastructure, such as the IPSS X.25
network, to carry Internet traffic. In 1984, University College London replaced
its transatlantic satellite links with TCP/IP over IPSS.
Many sites unable to link directly to the Internet started to create simple
gateways to allow transfer of e-mail, at that time the most important
application. Sites which only had intermittent connections used UUCP
or FidoNet and relied on the gateways between
these networks and the Internet. Some gateway services went beyond simple e-mail peering, such as allowing access to
FTP sites via UUCP or e-mail.
Evaluating Web Resources7
When using websites as opposed to full-text online databases to gather material
for your research, you’re taking a big chance. Anyone can post material to the
internet – and there is no one checking for accuracy. In fact, in a recent
study conducted by the PEW Internet & American Life Project, 86% of US
college students use the Internet and 73% of students use the Internet more
than the library for research. However, according to a study conducted by
Washington State University Library entitled the “Dangers of E-Illiteracy,” 83%
of internet sites are commercial, 70% of health and medical web information is
wrong or misleading and only 6 % of sites are educational or scientific. Hmmm –
I think learning to evaluate web resources for yourselves might be a very
valuable skill.
To best prepare yourself to evaluate the web resources, review the material
found in Evaluating Internet Sites 101. Make sure you take the embedded
quizzes.
If you feel you need to use information from a dedicated, stand-alone website,
make sure you can truthfully fill out the “Web Resource Warranty” which
guarantees that you have checked the site for
oAuthor
oAudience
oScholarship
oBias
oCurrency
oLinks
You can then attach the Warranty to the back of your Works Cited page and your
instructor will allow those resources.
Evaluating Web sites takes some practice. Fortunately, there are numerous
guides online that can offer advice about how to judge information that you
find on the Web. To help you to understand better the issues involved in
evaluating Web sites, we've sketched out some general concerns here. You can
explore these issues in more depth by following the links at the bottom of this
page.Always consider where the information you come across on the Web
originates. Still, don't simply let the Web address determine how you assess
information. Instead, use it as a way of focusing your attention as you
evaluate Web sites. Be aware that many URLs ending with .com may represent
businesses that provide Web space for any number of individuals or
organizations. You'll still need to look carefully at each individual item as
you evaluate its value.
Types of COMPUTER VIRUSES
"Macro" These viruses are spread by sharing document files
from MS-Word (version 6.0 and above) or MS-Excel (version 5.0 and above). Macro
viruses are a frequent cause of virus infections, and they can infect both PCs
and Macintosh computers. After your computer is infected with a macro virus,
any Word or Excel document you create or open may also contain the virus.
"Boot Sector" These viruses are spread by sharing diskettes
between different computers. Any diskette can spread a boot sector virus --even
if it is not a bootable system diskette. If you share files by sharing
diskettes, you can spread a boot sector virus to other computers, which then
can infect other diskettes, and it will spread on.
"Program" These viruses are spread by sharing program files.
Because most users share programs less frequently than they share data or
document files, this type of virus is less common than others. A program virus
can infect other programs and damage data files on your computer. So be careful
of what programs you install.
“Logic bomb” virus is a piece of code that are inputted into a software
system. When a certain and specific condition is met, such as clicking on an
internet browser or opening a particular file, the logic bomb virus is set off.
Many programmers set the
malicious virus off during days such as April Fools Day or Friday the 13th.
When the virus is activated, then various activities will take place. For
example, files are permanently deleted.
“Companion viruses” takes advantage of MS-DOS. This virus creates a new
file with typically the .COM extensions, but sometimes the .EXD extension as
well. When a user manually types in a program they desire without adding .EXE
or any other specific extention, DOS will make the assumption that the user
want the file with the extension that comes first in alphabetical order, and
thus running the virus. The companion virus is rare among Windows XP computers
as this particular operating system does not use the MS-DOS.
“Multipartite viruses” are spreaded through infected media and usually
hides in the memory. Gradually, the virus moves to the boot sector of the hard
drive and infects executable files on the hard drive and later across the
computer system.
Polymorphic Viruses - Polymorphic viruses change characteristics as they
infect a computer.
Stealth Viruses - Stealth viruses actively try to hide themselves from
anti-virus and system software.
Fast and Slow Infectors - Fast and Slow viruses infect a computer in a
particular way to try to avoid being detected by anti-virus software.
Sparse Infectors - Sparse Infectors don't infect very often.
Armored Viruses - Armored viruses are programmed to make eradication
difficult.
Multipartite Viruses - Multipartite Viruses are viruses that may fall
into more than one of these categories.
Cavity (Spacefiller) Viruses - Cavity (Spacefiller) viruses attempt to
maintain a constant file size when infecting a computer in order to try to
avoid detection.
Tunneling Viruses - Tunneling viruses try to "tunnel" under
anti-virus software while infecting.
Camouflage Viruses - Camouflage viruses attempt to appear as a benign
program.
Virus Droppers - Virus Droppers are a special category of programs that
place viruses on computers but are not by themselves an actual virus.
In general, there are two ways to send SMS messages from a
computer / PC to a mobile phone:
The SMS specification has defined a way for a computer to send
SMS messages through a mobile phone or GSM/GPRS modem. A GSM/GPRS modem is a
wireless modem that works with GSM/GPRS wireless networks. A wireless modem is
similar to a dial-up modem. The main difference is that a wireless modem
transmits data through a wireless network whereas a dial-up modem transmits
data through a copper telephone line. More information about GSM/GPRS modems
will be provided in the section "Introduction to GSM / GPRS Wireless Modems".
Most mobile phones can be used as a wireless modem. However, some mobile phones
have certain limitations comparing to GSM/GPRS modems. This will be discussed
in the section "Which is Better: Mobile Phone or
GSM / GPRS Modem" later.
To send SMS messages, first place a valid SIM card from a wireless carrier into
a mobile phone or GSM/GPRS modem, which is then connected to a computer. There
are several ways to connect a mobile phone or GSM/GPRS modem to a computer. For
example, they can be connected through a serial cable, a USB cable, a Bluetooth
link or an infrared link. The actual way to use depends on the capability of
the mobile phone or GSM/GPRS modem. For example, if a mobile phone does not
support Bluetooth, it cannot connect to the computer through a Bluetooth link.
After connecting a mobile phone or GSM/GPRS modem to a computer, you can
control the mobile phone or GSM/GPRS modem by sending instructions to it. The
instructions used for controlling the mobile phone or GSM/GPRS modem are called
AT commands. (AT commands are also used to control dial-up modems for wired
telephone system.) Dial-up modems, mobile phones and GSM/GPRS modems support a
common set of standard AT commands. In addition to this common set of standard
AT commands, mobile phones and GSM/GPRS modems support an extended set of AT
commands. One use of the extended AT commands is to control the sending and
receiving of SMS messages.
The following table lists the AT commands that are related to the writing and
sending of SMS messages:
|
AT
command |
Meaning |
|
+CMGS |
Send
message |
|
+CMSS |
Send
message from storage |
|
+CMGW |
Write
message to memory |
|
+CMGD |
Delete
message |
|
+CMGC |
Send
command |
|
+CMMS |
More
messages to send |
One way to send AT commands to a mobile phone or GSM/GPRS modem
is to use a terminal program. A terminal program's function is like this: It
sends the characters you typed to the mobile phone or GSM/GPRS modem. It then
displays the response it receives from the mobile phone or GSM/GPRS modem on the
screen. The terminal program on Microsoft Windows is called HyperTerminal. More
details about the use of Microsoft HyperTerminal can be found in the "How to Use Microsoft
HyperTerminal to Send AT Commands to a Mobile Phone or GSM/GPRS Modem"
section of this SMS tutorial.
Below shows a simple example that demonstrates how to use AT commands and the
HyperTerminal program of Microsoft Windows to send an SMS text message. The
lines in bold type are the command lines that should be entered in
HyperTerminal. The other lines are responses returned from the GSM / GPRS modem
or mobile phone.
In general, there are three ways to receive SMS messages using
your computer / PC:
A GSM modem is a wireless modem that works with a GSM wireless
network. A wireless modem behaves like a dial-up modem. The main difference
between them is that a dial-up modem sends and receives data through a fixed
telephone line while a wireless modem sends and receives data through radio
waves.
A GSM modem can be an external device or a PC Card / PCMCIA Card. Typically, an
external GSM modem is connected to a computer through a serial cable or a USB
cable. A GSM modem in the form of a PC Card / PCMCIA Card is designed for use
with a laptop computer. It should be inserted into one of the PC Card / PCMCIA
Card slots of a laptop computer.
Like a GSM mobile phone, a GSM modem requires a SIM card from a wireless
carrier in order to operate.
As mentioned in earlier sections of this SMS tutorial, computers use AT
commands to control modems. Both GSM modems and dial-up modems support a common
set of standard AT commands. You can use a GSM modem just like a dial-up modem.
In addition to the standard AT commands, GSM modems support an extended set of
AT commands. These extended AT commands are defined in the GSM standards. With
the extended AT commands, you can do things like:
A GPRS modem is a GSM modem that additionally supports the GPRS
technology for data transmission. GPRS stands for General Packet Radio Service.
It is a packet-switched technology that is an extension of GSM. (GSM is a
circuit-switched technology.) A key advantage of GPRS over GSM is that GPRS has
a higher data transmission speed.
GPRS can be used as the bearer of SMS. If SMS over GPRS is used, an SMS
transmission speed of about 30 SMS messages per minute may be achieved. This is
much faster than using the ordinary SMS over GSM, whose SMS transmission speed
is about 6 to 10 SMS messages per minute. A GPRS modem is needed to send and
receive SMS over GPRS. Note that some wireless carriers do not support the
sending and receiving of SMS over GPRS.
If you need to send or receive MMS messages, a GPRS modem is typically needed.
In general, a GSM/GPRS modem is recommended for use with a
computer to send and receive messages. This is because some mobile phones have
certain limitations comparing to GSM/GPRS modems. Some of the limitations are
described below:
What is FAX MACHINE
Short for facsimile machine, a device that can send or receive pictures
and text over a telephone line. Fax machines
work by digitizing an image -- dividing it into a
grid of dots. Each dot is either on or off,
depending on whether it is black or white. Electronically, each dot is
represented by a bit that has a value
of either 0 (off) or 1 (on). In this way, the fax machine translates a picture
into a series of zeros and ones (called a bit map) that can be transmitted like
normal computer data. On the receiving side, a fax machine
reads the incoming data, translates the
zeros and ones back into dots, and reprints the picture.
How To Use A Fax Machine
Objective: Learn to use the fax machine
Suggested Next Steps:
• None
FAX
Resources:
• None
Preparing a cover sheet
A cover sheet is just a page that has some important information for the person
on the receiving end of your fax. It should have the
following information so that your fax gets to the right person:
• To: Name of person you are sending fax to
• Recipient Fax Number: Put in the fax number that you are sending it to
(this is in case you accidentally send it to the wrong
number)
• Recipient Phone Number: Put in the phone number of the person you are
sending it to
• From: Put in your name
• Phone: Put in your phone number (so someone can call you if your fax
shows up all messed up)
• Memo: Always write a short memo to explain what the fax is for and who
it should go to. This will help ensure that your fax gets
to the right destination
• Number of pages including cover: Count all your pages and enter that
number in here (this helps ensure that people don’t
accidentally mistake your fax for complete if it is missing pages)
Loading Papers
• Place all documents to be faxed face up in the fax tray.
Sending Fax
• First dial area code + phone number to where the fax is going. (You
may have to dial “1” first, if the Area Code is different.)
• Once number is dialed, press the send button.
• Wait for the machine to send each fax.
• When finished, the fax machine will say “ Fax Complete”.
You have now completed your fax.
Simply put, e-commerce is the online transaction of business,
featuring linked computer systems of the vendor, host, and buyer. Electronic
transactions involve the transfer of ownership or rights to use a good or
service. Most people are familiar with business-to-consumer electronic business
(B2C). Common illustrations include Amazon.com, llbean.com, CompUSA.com,
travelocity.com, and hotels.com.
E-commerce can be divided into:
What is 3D Technology?
3D Core is a software component package that functions like a CAD engine, but
is easy to use and plug into various applications.
Its features make it ideal for metrology applications:
3DCore is an ideal choice if you must work on CAD models and
need a 3D view, but are not necessarily concerned with modeling and CAD design.
3DCore contains COM components to build three-dimensional "models"
and an ActiveX "view" component for visualization. It has a "multiple
document – multiple view" structure. This means that the application can
operate with more than one model and more than one view of a model.
The "Model" component is able to
These kinds of components (COM, ActiveX) are widely supported by
the current software technology and can be used in applications for example developed
in Visual C++, Delphi, Visual Basic or Java.
There is also a test-application (which is developed in Borland-Delphi) to
demonstrate/teach 3DCore’s usage. (It also demonstrates how easy it is to use
these components: a full functional IGES viewer can be written approx. in 500
program lines
Automatic Speech Recognition
Automatic Speech Recognition, or ASR, refers to the translation of speech to
text solely by a software program. A microphone worn by an instructor,
sends his/her speech to a computer program that prints out in text what was
said. This is the Star Trek dream of the all-understanding computer --
you talk, it understands. The task of understanding speech is a very
difficult one, however, and computer software analysis of today is not yet
perfect.
Automatic speech recognition (ASR) is the process by which a computer maps an
acoustic speech signal to text. A wide range of intelligent speech recognition
systems has been studied by researchers for use in various applications. Such
applications include voiced-command input for personal computers, voice dialing
for hands-free mobile phone solution and automatic speech-to-text conversion
for document dictation. The types of speech recognition systems span a large
domain: speaker dependent versus speaker independent; small, medium or large
vocabulary; and continuous against isolated word system.
In most recognition systems, feature extraction is usually carried out on the
unknown speech signal. These feature vectors, which carry the signature of the
speech, are then compared with the reference templates of the various speech
words.
Types of Speech Recognition Approach
Broadly speaking, there are three approaches to speech recognition, namely the
acoustic-phonetic approach, the artificial intelligence approach and the
pattern recognition approach.
The acoustic-phonetic approach is based on the theory of acoustic phonetics
that postulates that there exist finite, distinctive phonetic units in spoken
language and that the phonetic units are broadly characterised by a set of
properties that are manifest in the speech signal, or its spectrum, over time.
Hence, the recognition process requires the segmentation of the speech signal
into valid phonetic units and the determination of a valid words from the
sequence of phonetic labels. This approach hence requires the knowledge of
phonetic theory. On the other hand, it is suited for implementing applications
with semantic and grammatical constraints, such as voice-dictation.
The pattern recognition approach which does not require speech-specific
knowledge is used widely in ASR systems. The performance of the system is
sensitive to the amount of training data, speaking environment and transmission
characteristics of the medium used to create the speech. Since the system is
insensitive to sound classes (phrases, whole words or subword units), a basic
set of techniques can be developed and applied to the different sound classes.
However, one of the greatest constraint is that the amount of computational load
is generally proportional to the number of patterns to be recognised; hence, it
is not suitable for large vocabulary system. The implementation, however does
not command the need of the knowledge of phonetic theory, making it a popular
choice for most ASR system.
A Typical ASR System
A canonical ASR system operates in two phases: a training phase and a
recognition phase. The training phase is the stage during which the system
learns the reference patterns representing the different speech words that
constitute the vocabulary of the application. Following the training phase, the
recognition phase is the process in which an unknown input is identified by
considering the set of references. The recognition process consists of four
steps:
a. End-Point Detection
The first step to speech recognition requires the detection of the start and
end of an utterance. The endpoint detection problem is fairly straightforward
for high-level speech signals in low-level stationary noise environments.
However, this problem becomes considerably more difficult when either the
signals are too low in level, or when the background noise becomes highly
nonstationary. Studies have shown that the accuracy of endpoint detection is
crucial for reliable word recognition.
b. Feature Extraction
This second step focuses on the extraction of a set of parameters obtained by
some signal analysis method from successive portions of the speech signal. Some
of these analysis methods include Fast Fourier Transform (FFT), filtering
through digital filter-banks and Linear Predictive Coding (LPC). In the past
two decades, the technique of linear prediction has proved to be very useful in
providing an efficient representation of speech for a variety of speech
analysis applications.
c. Pattern Classification
During this step, a similarity measure is computed between the input speech and
each reference pattern. This process necessitates defining a local measure of
closeness between feature vectors and a method for aligning two speech patterns,
which may differ in duration and rate of speaking.
The measure between two speech utterances requires a trade-off between
mathematical tractability and perceptual considerations. It must, at the same
time, satisfy some mathematical properties and be meaningful on a perceptual or
phonetic point of view. Some of the common spectral distance measures are the
Itakura-Saito distortion measure, the Likelihood Ratio (LR), the Log Likelihood
Ratio (LLR), Weighted Cepstral coefficients and the Raised Sine Functions.
d. Decision
In this final step, the unknown pattern is assigned the label of the
"closest" reference pattern. Decision of this assignment is made
based on some rules which take into account the results of the similarity
measurements.
Multimedia
Multimedia (Lat. Multum + Medium) is media that uses multiple forms of information content and information processing (e.g. text, audio, graphics, animation, video, interactivity) to inform or entertain the
(user) audience. Multimedia also refers to the use of (but not limited
to) electronic media to store and experience
multimedia content. Multimedia is similar to traditional mixed media in fine art, but with a broader scope. The
term "rich media" is synonymous for interactive multimedia. Multimedia
means that computer info can be represented through audio, graphics, image,
video and animation in addition to traditional media(text and graphics). Hypermedia can be considered one particular
multimedia application.
The use of computers to
present text, graphics, video, animation, and sound in an integrated way. Long touted as the future
revolution in computing, multimedia applications were, until the mid-90s,
uncommon due to the expensive hardware required. With increases in
performance and decreases in price, however, multimedia is now commonplace.
Nearly all PCs are capable of displaying video, though the resolution available
depends on the power of the computer's video adapter and CPU.
Microsoft HyperTerminal is a small program that comes with
Microsoft Windows. You can use it to send AT commands to your mobile phone or
GSM/GPRS modem. It can be found at Start -> Programs -> Accessories
-> Communications -> HyperTerminal. If you cannot find it
and you are using Windows 98, then probably you have not installed it. You can
go to Control Panel -> Add/Remove Programs -> Windows
Setup tab -> Communications list box item -> Details
button to install MS HyperTerminal.
Before you start programming your SMS application, you may want to check if
your mobile phone, GSM/GPRS modem and SIM card are working properly first. The
MS HyperTerminal is a handy tool when it comes to testing your GSM devices. It
is a good idea to test your GSM devices beforehand. When a problem occurs,
sometimes it is difficult to tell what causes the problem. The cause can be
your program, the GSM device or the SIM card. If you test your GSM device and
SIM card with MS HyperTerminal and they operate properly, then it is very
likely that the problem is caused by your program.
To use MS HyperTerminal to send AT commands to your mobile phone
or GSM/GPRS modem, you can follow the procedure below:
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Figure 5. The screenshot of MS HyperTerminal's Connection
Description dialog box in Windows 98. |
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Figure 6. The screenshot of MS HyperTerminal's Connect To dialog
box in Windows 98. |
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Figure 7. The screenshot of MS HyperTerminal's Properties
dialog box in Windows 98. |
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Figure 8. The screenshot of MS HyperTerminal's main window in
Windows 98. |
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Internet Security
Internet security is the process of protecting data and privacy of devices connected to internet from information robbery, hacking, malware infection and unwanted software.
For more details on this topic, see router.
Network Address Translation
(NAT) typically has the effect of preventing connections from being established
inbound into a computer, whilst permitting connections out. Getting a router in
your home improves the security of a home LAN; some people consider that they don't
need a firewall if they have a router. However, for a small home network,
software NAT can be used
on the computer with the internet connection, providing similar behaviour to a
router, and similar levels of security but for a lower cost and lower
complexity.
For more details on this topic, see firewall.
A firewall blocks all traffic except through
authorized ports on your
computer, thus restricting unfettered access. A stateful firewall is a more secure form of
firewall, and system administrators often combine a proxy firewall
with a packet-filtering firewall to create a highly secure system; this would
be overkill for a home system, but is more common in business. Most home users
would use a software firewall,
while some high risk servers and computers might need a hardware firewall.
For more details on this topic, see malware.
Some bad people or companies write programs like computer viruses, worms, trojan horses and spyware. These programs are all
characterised as being unwanted software that install themselves on your
computer through deception.
Trojan horses are simply programs that conceal their true purpose or
include a hidden functionality that a user would not want.
Worms are characterised by having the ability to replicate themselves
and viruses are similar except that they achieve this by adding their code onto
third party software. Once a virus or worm has infected a computer, it would
typically infect other programs (in the case of viruses) and other computers.
Viruses also slow down system performance and cause strange system
behavior and in many cases do serious harm to computers, either as deliberate,
malicious damage or as unintentional side effects. In order to prevent damage
by viruses and worms, you need either to completely isolate your computer from
dangers (impractical for many people or networks) or install antivirus software, which typically runs
in the background on your computer, detecting any suspicious software and
preventing it from running.
Some malware that can be classified as
trojans with a limited payload are not detected by most antivirus software and
may require the use of other software designed to detect other classes of
malware, including spyware.
Generally anti-virus software may be also be used to scan all of the
files on a computer occasionally for extra peace of mind. Because of the
continuing increase in the number of viruses and worms being identified, all
good anti-virus software includes a facility to regularly update the data that
is used to identify viruses. As well as the commercial antivirus programs,
which generally require an annual subscription, there are free antivirus
programs available, but the best commercial programs appear to be a little more
reliable at present. Several companies provide a comparison of the performance
of different antivirus programs which should be useful in making a decision as
to which to use.
For more details on this topic, see malware.
There are several kinds of threats:
What is E-Mail Address?
A name that identifies an electronic post
office box on a network where e-mail can be sent. Different types of
networks have different formats for e-mail addresses. On the Internet, all e-mail addresses have the
form:
· @<domain name >
For example,
· webmaster@sandybay.com
Every user on the Internet has a unique e-mail address. The term e-address
is commonly used as an abbreviation for e-mail address.
If the parent has an e-mail address and would like to be notified when the
student’s FAFSA has been processed, enter the e-mail address now. If the parent
does not want us to communicate with them electronically, please leave the
e-mail address blank.
We will not use this e-mail for purposes other than informing the parents the
date the student’s application was processed. See the Privacy Act for more
information on the way we use the information the student provided on this
form.
When entering the parent's e-mail address, please follow the rules below:
What is CHATTING?
On the Internet, chatting is talking to other people who are using the Internet
at the same time you are. Usually, this "talking" is the exchange of
typed-in messages requiring one site as the repository for the messages (or
"chat site") and a group of users who take part from anywhere on the
Internet. In some cases, a private chat can be arranged between two parties who
meet initially in a group chat. Chats can be ongoing or scheduled for a
particular time and duration. Most chats are focused on a particular topic of
interest and some involve guest experts or famous people who "talk"
to anyone joining the chat. (Transcripts of a chat can be archived for later
reference.)
Chats are conducted on online services (especially America Online), by bulletin
board services, and by Web sites. Several Web sites, notably Talk City, exist
solely for the purpose of conducting chats. Some chat sites such as Worlds Chat
allow participants to assume the role or appearance of an avatar
What is SMS Messaging
SMS (Short Message Service) is a text message that can be sent from your
computer or cell phone to another cell phone. You can also send text messages
to other wireless devices. SMS.ac allows you to stay always connected
by connecting your mobile phone with the Internet. So use the SMS.ac web site
to send instant text messages to your friends and family or start making new
friends! It's fast. It's easy. And it's cool!
Short Messaging Service, otherwise known as text messaging, mobile messaging,
or alphanumeric paging is a digital cellular network feature. It lets you send
short text and numeric messages to and from digital cell phones, cell phones
and e-mail addresses, as well as cell phones and public SMS messaging gateways
on the Internet.
SMS is convenient and cost effective for a number of reasons. When you compare
it with the cost of airtime for voice calls or wireless web access, SMS is a
real bargain. Messages can be received while making voice calls, and there are
no busy signals to contend with. Plus, if you should you find yourself in a
situation where talking on a cell phone is inappropriate, SMS is silent and
discreet. Messages generated by SMS are immediately delivered directly to your
phone. There is no need to call an access number, as is the case with
voice-mail. Also, most carriers offer SMS alerts (information packets, such as
stock quotes, sports scores, and news) that can be delivered to your phone at regularly
scheduled intervals.
Currently, there are approximately 30 billion SMS messages sent globally each
month, with the majority of that traffic occurring in Western Europe and Asia.
In North America most major cellular providers offer either one-way or two-way
SMS to their subscribers. With one-way service, you can receive messages; while
with two-way service, you can both receive and send messages.
SMS is a success all over the world. The number of SMS messages
exchanged every day is enormous. SMS messaging is now one of the most important
revenue sources of wireless carriers. What is so special about SMS that makes
it so popular worldwide? Some of the reasons are discussed below.
Nowadays, almost every person has a mobile phone and carries it
most of the time. With a mobile phone, you can send and read SMS messages at
any time, no matter you are in your office, on a bus or at home.
Unlike a phone call, you can send an SMS message to your friend
even when he/she has not switched on the mobile phone or when he/she is in a
place where the wireless signal is temporarily unavailable. The SMS system of
the mobile network operator will store the SMS message and later send it to
your friend when his/her mobile phone is online.
Unlike a phone call, you do not need to read or reply an SMS message
immediately. Besides, writing and reading SMS messages do not make any noise.
While you have to run out of a theater or library to answer a phone call, you
do not need to do so if SMS messaging is used.
SMS messaging is a very mature technology. All GSM mobile phones
support it. Not only that you can exchange SMS messages with mobile users of
the same wireless carrier, but you can also exchange SMS messages with mobile
users of many other wireless carriers worldwide.
Here are some of the reasons that make SMS a suitable technology
for wireless applications to build on:
What SMS Centre?
There are several unique features to Short Message Service (SMS), as defined
within the GSM digital mobile phone standard that is popular in Europe, the
Middle East, Asia, Africa and some parts of North America: