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WEB TECHNLOGIES
UNIT-V

1. Explain Ne wsgroup a nd its terminology.

Ne wsgroup: A newsgroup is a discussion group in which computer users throughout the world
participate. Users interested in a particular topic may subscribe to the same newsgroup. Boundaries such
as age, gender and background generally do not play a role in the discussion, since users usually only see
messages f rom each other. Someone can email a message called an article to the newsgroup at any
time. The message then becomes available for others to read. They can respond to the article sharing
their opinions or expertise. This in turn may stimulate others to respond. In this way, a question or an
opinion can create a lively and lengthy discussion.

Ne wsgroup Te rminology: Most of the terminology for newsgroups is borrowed from
newspaper news.

Article: A message written and sent to a newsgroup.
Post: A synony m for article.
Posting: The process of sending an article to a newsgroup.
Follow-up: An article that is posted in response to a previous news group article.
Thread: A collection of one or more fellow-up articles together with the original posting.
Subscribe: The procedure user follows to add a newsgroup to the list of those read on regular basis. Once
subscribed, user will receive the new postings of the newsgroup.
Unsubscribe: The process of removing a newsgroup f rom the list of those user read. User must have been
subscribed in order to unsubscribe.
Newsreader: A program that servers as the user interface for newsgroups. Newsreaders allow users to
read, post, subscribe and unsubscribe from newsgroups among other things. User should select a
newsreader that also displays threads.
News client: A synony m for newsreader.
Expired news: News that is removed from a system usually after a short period of time.
News server: A computer that saves forwards and manages news articles. Normally, each organization
runs its own news server and limits access to its customers or user community.
News feed: A news feed that prov ides recent articles to a new client. The term also encompasses the
process of delivering the news articles themselves.
Way-station: A news server that functions as news feed for at least two and usually many more other
sites.
Network News Transfer Protocol(NNTP): The protocol used for distributing news articles.
News administrator: A person who is in charge of running a news server. The news system is distributed
and each site that receives and posts news must have a site administrator. This person is in charge of
determining what news will be received by this site. Administrators can also add or delete newsgroups.
The email address for this person is usually ne wsmaster@domain, where domain is replaced by the
appropriate site name.
News moderator: A person associated with a specific newsgroup w ho reads and critically evaluates all
articles submitted for posting to the newsgroup and then decides w hether or not each article should be
posted.
Moderated newsgroup: A newsgroup that has a moderator.
Unmoderated newsgroup: A newsgroup that has no moderator. Because a good moderator can filter out
poor irrelevant posts, moderated newsgroup posts sometime have more valuable content than
unmoderated newsgroup articles.
Cross-post: The process of simultaneously submitting the same article to two or more newsgroups.
Digest: A collection of related articles usually edited that is posted as an article to a newsgroup.
Kill-files: A filter based on names or topics that user specifies so that user is not even shown those
messages.

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2. Explain Ma il List Fundame ntals.

A mailing list is a group of users with a shared interest whose email addresses are collected in
an electronic list that can be user to send email to each member on the list. The key to a mailing list is a
program called a list se rver w hich receives and distributed postings and automatically manages
subscriptions.

Mailing list provide a forum in which users from all over the world can ask questions and have
them answered by others with similar interests.

To participate in a mailing list, user has to know how to use email. There is no need to learn
new software. For a mailing list, a user posts message to a special mailing list program called t he list
server which has email addresses of all the users subscribed to the list. The list management program
then distributes the message to each member on the list via email.

Mailing List Te rminology: Much of the terminology used with newsgroups carries over to
mailing lists. Terms like article, cross-post, follow-up, post, posting, subscribe, thread and unsubscribe can
all be used in the mailing list.

Additional terms are:

Subscriber: A person w hose email address is on an electronic mailing list. They will receive all posts to the
list. Note that for the majority of mailing lists, subscription is free.
List owner: The person in-charge of a mailing list. While most mailing lists have only one person who
handles the administrative duties, sometimes a couple of people may split the responsibilities.
List administrator: Synony m to List owner.
List coordinator: Synony m to List owner.
List manager: Sy nony m to List owner.
Lurker: A person who is subscribed to and reads a mailing list but does not post messages. Such a person
is said to lurk.
Closed list: A mailing list for w hich the list owner either accepts or rejects subscriptions. List membership
is filtered. It is not possible to subscribe automatically to a closed list. Only postings from subscribers are
accepted.
Private list: Synony m to Closed List.
Newbie: A person who only recently joined a mailing list.
Open list: A mailing list to which anyone subscribes. Such a list typically accepts posts even from users
who are not subscribers.
Edited list: A mailing list in which posts to the lists may be edited by the list owner or moderator.
Digested list: A mailing list in which postings are grouped by topic and sent out as batches instead of
indiv idually. Sometimes, when user subscribes, we have a choice of getting either indiv idual postings or
digests.

3. Explain a bout Chat Rooms and Chat Room Entrance.

Chat Room: A chat room is a forum through which users can interactively discuss their favorite
subject with people located anywhere on the internet. A chat room is a virtual room in which two or more
people with a common interest (entertainment, literature, movies, music, politics, religion and so on) can
share ideas and have a real-time conversation.

The chat room is actually a channel or path that allows communication between two or more
computers on the internet. The communication occurs in real time and is similar to a conference call or
meeting. However, messages are typed on the keyboard and the conversation appears on the monit ors of
all the users on that channel.

Chat Room Entra nce: When signing into a char room for the first time, user is asked to select
a username and password. Unless the chat room is moderated and the moderators wants the user to use

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the real name, the user may create any username (or nickname) liked, prov iding it is not already in use.
The user also needs to create a password. The user is asked to fill a form containing such data as name,
password, date of birth, occupation, email address, etc. This information can be used for authentication
and also for advertising purposes.

Once a user is signed in with a chat service, he can select a “room” to which he wants to go. The number
of participants in each room is displayed either via a number or list of the room’s occupants.

When a chat room is active, a scrolling window displays the “conversation” as lines of text, each
line preceded by the nickname of the person who “spoke”. A second area called message box is provided
in which the user can type his own message. Level of privacy is the choice of the user like whether to
display their pictures or URL in the chat rooms. Third area is prov ided to display the list of users or
usernames of all people in the chat room. Selecting someone from the list allows user to send a priv ate
message to them opening a private chat window.

In a chat room, message box also provides to select emoticons such as smile or w ink, to
accompany the message. Several buttons allow user to submit the message, go to another chat room, or
refresh the screen if the user have been idle for a period of time.

4. Explain a bout Multi- User Dime nsion.

Multi- User Dimension (MUD): It is a real-time interactive game that takes place in an imaginary
environment where multiple computers users can play simultaneously. It is a 3D World. MUDs originated
in 1979 when Richard Bartle and Roy Trubahaw w rote a game program that allowed multiple users to play
and interact at the same time.

To participate in a MUD, user needs to connect Telnet to a server running a MUD. Using a
search engine, user can easily generate a list of currently available MUDs. User can connect to a MUD by
using telnet command and specifying the MUD’s network address and port number.

Some examples are:
· MAcMOOSE (Macintosh)
· TinyTalk (UNIX)
· MUSHClient (PC Winsock)

When user connects to a MUD for the first time, user should read the welcome screen. The
welcome screen permits to either create a character by placing a name and password or by connecting
with existing name and password. The introductory screen provides other useful information about the
game such as the rules and where to find help. It also provides information about the background story of
the game. Before starting to play, new players should try to become familiar with the commands.

Commands used are:
· Emote – indicate an action, such as a sigh or laugh.
· Help – provide help.
· Look – Describe the contents of the room
· Page – talk to someone in another room
· Say – speak to everyone in the room.
· Who – List who is play ing.

5. Explain a bout Multime dia Audio a nd Video formats.

Audio: The term audio refers to a sound. A number of audio formats exist and audio can be included in a
web page.
A large number of audio file formats are in use. They are:
· AIFF(.aif, .aiff and .aifc) which stands for Audio Interchange File Format. This format was
developed by Apple.

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· AU(.au and .snd) stands for Unix Audio and Unix Sound. This format was developed by Sun
Microsystems.
· MIDI(.midi and .mid) stands for Musical Instrument Digital Interface. This format was developed
by MIDI Manufacture Association(MMA).
· Rea lAudio(.ra and .ram). This format was developed by Progressive Networks.
· WAV(.wav) stands for Wave format. It is developed by Microsoft.

Audio and Web Pages: 1. One approach to include an audio file in a web page involves object tag,
<OBJECT > and its corresponding ending tag </OBJECT >

To include the WAV audio f ile called my music.wav using the object tag, we can use the follow ing
code:
<OBJECT DATA=”mymusic. wav”
TY PE=”audio/wav”>

</OBJEC T>

The DATA attribute specifies the source file and the TYPE attribute specifies the object’s MIME type.

2. Microsoft Internet Explorer supports the background sound tag <BGSOUND> .To include the audio
file , we can use the following code:

<BGSOUND SRC=”mymusc.wav”>

The BGSOUND tag also supports the LOOP attribute. LOOP can be assigned a natural numb er
indicating the number of times the audio f ile is to be played or it can take a value of infinite indicating
that the sound should be played endlessly.

Movies and Video: Online v ideo in essence is a motion picture. A video may or may not include
sound. Because of video consists of many images frames plus audio, video files are much larger than
audio files. This means that downloading a video file takes a long time than audio.

A large number of video formats are currently in use. Some of the most popular are:
· AVI (.avi) which stands for Audio Video Interleaved. This format is developed by Microsft.
· MPEG (.mpeg or .mpg) which stands for Motion Picture Experts Group or Mov ing Picture
Experts Group. This format was developed by the Motion Picture Experts Group.
· Quic kTime (.qt or .mov) . This stands for QuickTime or Movie. This format was developed by
Apple.

Video and Web Pages:

To include the AVI file called my movie.av i using the object tag, we can use the following code:

<OBJECT DATA=”mymove.avi”
TY PE=”video/msvideo”
Height=”150”
Width=”150” >

<PARAM NAME=”autosta rt” VALUE=”true”>

Please install Plug-in to use.

</OBJEC T>

Values specified in the parameter tag are passed directly to the corresponding plug-in and are
not processed by the browser. For example, the browser uses the DATA attribute to load the

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appropriate file, the TYPE attribute to obtain the MIME type of the file and the HEIGHT and WIDTH
attributes to layout the required amount of space on the screen for the multimedia element.

However, the value true assigned to the parameter autostart is passed directly to the plug-in
itself. This tells the plug-in to start playing the mov ie as soon as it is loaded.

6. De fine Virtual Rea lty in 3D Modeling.
Or
Ex pla in VRML a nd QTVR.

Virtual Reality involves a three-dimensional simulation of a real or imagined env ironment using
computers. A lot of applications are suited to 3D displays from engineering designs to medical research
and imaging to on-line art galleries to games. If an object such as a cube is being displayed in a virtual
realty setting, we can examine the cube from various points of view (top, bottom, right and left).
Software for creating 3D solid figures and line draw ings has been available for some time. However, the
first step was creation of static images. Initially, users were not able to interact with the object being
rendered. Adding dynamic user interaction has greatly enhanced the interest in 3D modeling.

Virtual Reality is becoming another exciting extension of the web. The development of 3D world and
objects and 3D browsers in which to view them is bringing us closer to Web-based virtual reality. Even
while 2D graphical browsers were being introduced and accepted, 3D specifications were already in the
planning stages.

VRML (Virtual Reality Mode ling La ngua ge):
Initially called Virtual Reality MarkUp Language, the VRML 1.0 specification, was originally
established by Silicon Graphics to use simple text based files to create virtual reality env ironments. The
first release of VRML produced env ironments that were static and non-interactive. The current version is
VRML97 and the specification that defines it is VRML 2.0. This collaborative effort extends the
capabilities of VRML 1.0 by supporting interaction, motion, and sound. A VRML world does not have to
model something geographic; any object can be modeled as a VRML world.

A VRML file is a plaintext or compressed text file. Such files are identified by a f ile extension of
.wrl, .w rl.gz, .wrz and they have a MIME type of model/v rml. Where HTML files are rendered as pages
by a browser, VRML files are rendered as worlds (w rl stands for world). The z at the end of the file
extension .gz and .wrz denotes a zip or compressed file.

Viewing a VRML world requires a special VRML v iewer or a plug-in. If user doesn’t have
necessary viewer, then user can try to open a VRML file. Browser w ill complain and ask the user to
install the appropriate plug-in.

The latest version of internet explorer and Netscape come bundled with v iewers that support
VRML. Other browsers require dow nloading an appropriate plug-in.

Virtual World Creation Tools: As with an HTML file, a text editor is all that is required to
create a VRML file, since it just consists of plaintext. Since VRML files contain information that describes
cameras, colors, even handlers, lighting, 3D objects and textures, these files are quite complex. Because
of this many VRML authors use modeling software to help them create their VRML files. Modeling
software offers WYSIWYG tools for authoring VRML worlds.

Converters that permit to convert 3D and CAD (Computer-Aided Design) file formats to the
VRML file format are also available. Other converters can convert VRML 1.0 to VRML 2.0.

Virtual Reality and Web Pages: Once we have a VRML file, there are several ways to include
it in a 2D web presentation.
1. One approach involves prov iding a hyperlink to the VRML file from HTML documents using an
anchor tag.

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<A HREF=”a rtga lle ry.wrl”> 3D World </A>

2. The other approach is include VRML file in HTML document as follows:

<OBJECT DATA=”a rtga lle ry.wrl”
TY PE=”model/v rml”
Height=”200”
Width=”200” >

<PARAM NAME=”color” VALUE=”brown” >

Please install Plug-in to use.

</OBJEC T>

3. A VRML world can also be included in a frame.

<F RAME SRC=”a rtga lle ry.wrl” name =”3D Pic utures”>

Displays the virtual world artgallery.wrl in its own frame named 3D Pictures.

QTVR (QucikTime Virtua l Reality):
Another virtual reality implementation found on the web uses QuickTime Virtual Reality
(QTVR) also called QuickTime VR. This technology was designed by Apple and was introduced in
1995. While a Mac is necessary to create the virtual-reality style 3D objects, any Mac PC can be
used to view them.

A 3D panorama (scene) created by QTVR is actually called QuickTime mov ie (f ile
extension .mov) that represents a 360 degree image. A QuickTime VR movie can be included in a
webpage in the same way as a VRML file. Nav igating through the mov ie gives users the
impression that they are in 3D world. Creating a panorama involves working w ith photographs or
3D Computer-generated images. It requires a great deal of technical skill.

To view QTVR, we need a QTVR plug-in. The QTVR plug-in interprets and responds to
the movements as user navigates through a scene or manipulates an object.

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