MC9235 WEB PROGRAMMING Question Bank UNIT I PART - A 1 (A) 1What is an ARPAnet?

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MC9235
WEB

PROGRAMMING

Question Bank

UNIT


I

PART
-

A

1 (A) 1

What is an ARPAnet?

Advanced Research Project Agency Net. It allows multiple users to send & receive
information at the same time, over the same communication paths with the phone lines with
the help o
f network.

1 (A) 2

What is E
-
mail?

Electronic mail is a method of sending formatted messages and files over the internet

to the
other people.

1 (A) 3

What is packet switching.?

The network operated with a technique called packet switching in which digital data was sent
i
n small packages called packets.the packets contain data,address,information,error control
information and sequencing information.

1 (A) 4

Define Internet.

Internet id the network of computer networks.It makes it possible for any computer
connected to it to send &

receive data from any other computer connected to it.

1 (A) 5

Define WWW.

The
world wide web

-

Allows a computer user to locate and view multimedia based
document on almost any subjects.WWW is a name given to the entire part of the internet that
a user can acces
s using web browsing software. web browsers are Internet Explorer,
Netscape Navigator,

Opera,

Mozilla.

1 (A) 6

What is Bandwidth?

Information carrying capacity on the internet is called a bandwidth.

1 (A) 7

Define Multitasking.

A mechanism to allow the programmer to spe
cify many activities are to occur in parallel.

1 (A) 8

List out names of web brow
s
ers used to display HTML pages.

Microsoft Internet Explorer,

NetscapeCommunicator, Opera,

Euroda,

Mozilla

1 (A) 9

Write the Acronym for HTML,WWW
,
TCP/IP,

ARPANET.

HTML
-
Hyper Text Markup Lang
uage

WWW
-

World Wide Web

TCP/IP
-

Transmission Control Protocol/Internet Protocol

ARPANET.
-
Advanced R
esearch Project Agency Network.

1 (A) 10

What
are

functionalities of FTP?

(NOV 2012)

It is used to find files from one system to another under userCommand.It provide
w features
for controlling user access.Both text & binary files are accommodated.

1 (A) 11

What is a Newsgroup?

A process can post message to a shade ojn line viewing area.Other people can then view
these messages reply to them and post new messages.Tens of 1000’s
of newgroups are
available

on virtually any topic and newgroups are created daily.

1 (A) 12

Write the a
dvantages of E
-
mail

It is one of the
m
ost heavily used internet devices.

An e
-
mail message can go anywhere in the
world as little as a few second.

There are many
popular E
-
mail programs outlook Express,

Eudora and many of those have special features that are available on the internet for free
download.

Y
ou can manage more than one e
-
mil account.

1 (A) 13

Write down the steps involved in resolving domain names into IP
addres
ses.

A user program request for an IP address for a domain name.

A resolves in the local host
formulates a query for the local name server.

A local name server checks the name is in its
local database or cache and if so, returns the IP address to the reque
sted.

The user program is
given the IP addressor an error message.

1 (A) 14

List out the
functionalities

of Telnet?

It provides remote logon
capability, which evaluates

a user at a terminal or PC to logon to a
remote computer.

User teln
e
t interacts with the termina
l I/O module to communicate with a
local terminal.

Server telnet interacts with the application, so that remote terminal appears as
local to the application.

1 (A) 15

What is the router? How does it work?

A device that determines the next network point to which a d
ata packet should be forwarded
enroute toward its destination. The router is connected to at least two networks and
determines which way to send each data packet based on its current understanding of the
state of the networks it is connected to. Routers cr
eate or maintain a table of the available
routes and use this information to determine the best route for a given data packet.


1 (A) 16

Why IP

is
called
connectionless?

IP provides a connectionless, unreliable, best
-
effort packet delivery service. Its service is

called connectionless because it resembles the Postal Service more than it does the telephone
system. IP packets, like telegrams or mail messages, are treated independently. Each packet
is stamped with the addresses of the receiver and the sender.

1 (A) 17

What i
s Inet address?

Every computer connected to a network has an IP address. An IP address is a number that
uniquely identifies each computer on the Net. An IP address is a 32
-
bit number.

1 (A) 18

What is Domain Naming Service(DNS)

(NOV 2012)

It is very difficult to r
emember a set of numbers(IP address) to connect to the Internet. The
Domain Naming Service(DNS) is used to overcome this problem. It maps one particular IP
address to a string of characters. For example, www. mascom. com

1 (A) 19

What is the difference between TCP
/IP and UDP

TCP/IP is a two
-
way communication between the client and the server and it is a reliable and
there is a confirmation regarding reaching the message to the destination. It is like a
phone

call. UDP is a one
-
way communication only between the client and the server and it is not a
reliable and there is no confirmation regarding reaching the message.

1 (A) 20

W
hat

is UNICODE?

Unicode is used for internal representation of characters and strings and it uses 16 bits to
represent each other.


1 (A) 21

How do you define a host on the Internet?

Each computer on the internet is called a host computer or host. The computers on

the
internet are connected by a cables, phone lines and satellite connection.

1 (A) 22

What is Instant messaging? How do you activate it?

Instant messaging is a form of real
-
time direct text
-
based communication between two or
more people using
personal computers

or other devices, along with shared
software clients
.
The user's
text

is conveyed over a
network
, such as the
Internet
.

1 (A) 23

Why IRC is more powerful in the internet?

It is the original real
-
time group chat program.

1 (A) 24

How to avoid the email viruses?

Regular filters can be used to avoid email viruses. Outlook provides the feature to find &
filter junk email
.

1 (A) 25

Mention the
advantages of filtering E
-
mail.

Filtering helps in getting rid of unwanted mail. All the major e
-
mail packages
allows us to filter incoming messages.



Part B


PART
-

B (40 Marks)

1 (B) 1


(a) (i) Describe Instant Messaging





(
8)



Definition



ICQ



AOL Instant Messenger



Yahoo Messenger



MSN Messenger


(ii) Write notes on Voice and Video Conferencing

(NOV 2012)



(8)



Definition of Voice & Video conferencing



Getting voice & video hardware



Maki
ng phonecalls over the internet



Voice & Video conferencing using Instant messenger



Netmeeting

(OR)

1 (B) 2

Explain Online chatting, Messaging and Conferencing Concepts


(16)




Forms of Chat, messaging and conferencing



How does chat work



Chat & conferencing Etiq
uette



Safety while chatting



Ways to use chat effectively

1 (B) 3

(a) (i) Write short notes on Domain Name System.



(8)



Definition



How Domains are organized



Registering a domain name



(ii)
Describe Email concepts








(8)



Email Addressing



M
essage Header



Downloading Email



Web Based Email



Formatted Email

(OR)

1 (B) 4


(b) Discuss spam protection and Usenet group in detail with

suitable example.

(NOV 2012)








(16)

Spam Protection:



Controlling Email volume
and reducing spam



Adva
ntages of filtering email



Virus Security issues



Filtering mail & deleting
spam

Usenet Group:



Definition



Finding Interesting news group



Choosing what to read & post



Creation of news group

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1 (B) 5

(a) What are the minimum hardware and software
requirement
s

needed to connect to the Internet?








(8)



Types of Internet Connections



Gateway

(OR)

1 (B) 6

(b) Explain Internet Relay Chat (8)



Definition



Chatting in mIRC



IRC commands



Channel



General IRC tips



Starting & managing a channel



1 (B) 1

Ex
plain about the history of internet

1 (B) 2

Write a HTML file which will display a table that has five rows and four



columns

1 (B) 3

Highlight the features of browser object and list important properties of



each object

1 (B) 4

Explain about TCP
/IP

1 (B) 5

Highlight the features of SMTP and POP protocol

1 (B) 6

Describe the features of newsgroup and telnet

1 (B) 7

Why does TELNET protocol require a timesharing operating system?

1 (B) 8

Explain about the UUCP

1 (B) 9

Explain about the Telnet

1 (B) 10

Explain about the Finger.


UNIT


II

Part A

2.A.1

W
hat are the common tags of a HTML program?

The common tags are


(i) <HTML>….</HTML>

It should always be the first &last lines of code in your HTML file .



(ii) comments <!

and end with
--

>

The browser ignores any text and /or tags placed inside a commen
t .


(iii)<HEAD>…</HEAD>

Shows the header section of your page.


(iv).<TITLE>…</TITLE>

It will names your page appears on the colored bar at the top of the browser window.


(v)<BODY>….</BODY>

The body of the html document. Here you all content you would li
ke browser to display.


(iv) <P>….</P>

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All text placed between this forms one paragraph.


2.A.2

Write a note on header tags?

Every HTML file is separated into a header element, which generally contains information
about the document and a body which contains the

page content.


<head>

<Title> Internet and www How to program</Title>

</head>

shows the header section of our web page

2.A.3

What is text styling and what are the tags used for that?

In Html , text can be highlighted with bold underlined and /or italicized sty
les.

(i)

Underlined tag.. <u> ….</u> text enclosed in this is displayed as underlined.

Eg.<u> welcome</u>

(ii)

Emphasis or italic style tag ..
<em>…</em> eg.<em> HTML </em>

(iii)

Strong or bold tag <strong>….</strong>

2.A.4

How a page will be linked with another page usin
g HTML.


The most important capability of html is its ability to create hyperlinks to documents
elsewhere on the server and on different servers and thereby make possible a world

wide
network of linked documents and information.

In Html both text a
nd images can act as
anchors to link to other pages on the web

2.A.5

What is the purpose of MIME?

(NOV 2012)



MIME is a standard for specifying the format of content some other MIME types are
text/html,

image/gif and text/javascript.

Regula
r

text style
sh
ee
ts always use the MIME type
text/css.

2.A.6

What is a URL?


A URL is displayed in the address bar toward the top of the browser window.

The URL
describes the location of the file your browser is displaying or loading.

2.A.7

What are the types of MIME availa
ble?

There are 7 types of MIME

Text,

Multipart,

Message,

Image,Video,

Audio,

Application

2.A.8

List out the properties of search engines?



Make new search



Searching window



Searching toolbar button



Searching categories

2.A.9

What does the content
-
type of MIME contains?

The type attribute specifies the MIME type of the following style sheet .MIME is a standard
for specifying the format of content some other MIME types are text/html,

image/gif

and
text/javascript.

Regular text style sheets always use the MIME type text/css
.

2.A.10

Write HTML code to display the following error messages generated by
a web server

I
n response to an illegal request by a browser.

The message consists of a header in the first
line.



Bad request



The

browser has sent an illegal request.

2.A.11

How do you define a

host on the Internet?

Each computer on the internet is called a host computer or host. The computers on the
internet are connected by a cables,
phone lines

and satellite connection.

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2.A.12
How do you provide audio and video effect to web sites?

Using Hyper

Reference mention the path of the audio and video files.

2.A.13
What is a database?

A database is a tool for storing information in a structured way. The information is stored in
tables, and the tables are accessed by using database information access com
mands. Some
common database systems are PostgreSQL, MySQL, Oracle and Microsoft Access.


2.A.14
What is a database
-
driven website?

A database
-
driven website uses a database to gather, display, or manipulate information.
This is in contrast to a static site,

which stores text entirely in HTML and graphics such as
photos in folders on the Web server. With dynamic sites, Web pages are created on the fly
through the use of programming languages or scripts, which store or retrieve data in the
database. Site owner
s, however, don't have to worry about learning a programming
language. They interact with the site through an easy
-
to
-
use content management system, or
CMS. All content management systems can be designed and tailored to your specific
requirements.

Here's h
ow a dynamic site works: A visitor clicks on a link to a dynamic page. The request
is sent to the server, which queries the database and builds the site

2.A.15
What are dynamic Web pages and how do they differ from static Web pages?

Static Web pages always
look the same and the content rarely changes. To make a change,
you must create the page yourself or request a Web designer to do it for you. The newly
created page and any images must then be uploaded to the Web servers.

Dynamic pages are the opposite. Th
ey can change every time they are loaded (without
anyone having to make those changes), and they can even change their content based on
what your website visitors do. The dynamic page can be created to respond to information
entered by your site's visitor.

Dynamic pages are created using information from a database. The Web pages are instantly
created when the software "interrogates" your database, and the necessary information and
images are returned.


2.A.16.
What type of information is suitable for a data
base?

In some ways, any information can be ported to a database, but some things are better suited
than others. For example, address and phone lists, product inventories, lists of information
and price are ideal for databases. If you don't have a lot of in
formation, a static Web page
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may be the easiest way to display it. But if you have large amounts, or you want to display
the same content in multiple places, a database makes the job much easier.


2.A..17
How to deny specific users access to the FTP server

?


To deny specific users access to the FTP server, add their usernames to the /etc/vsftpd/

ftpusers file. By default, system users such as root and nobody are included in this list.






2.B.1 Explain the Web Security, Privacy, and Site
-
Blocking

(NOV 20
12)



Web Security and Privacy Concepts



Stand
-
alone computers have Security Policy associated with them that can be
modified by users with the appropriate rights.



When a computer joins a domain, the domain Security Policy is applied to the local
computer.



Domain Security Policy will override any changes made to Security Policy at the
desktop level.



Web security defines what the browser will allow web pages to run or store on the
computer.



Browsers have security policies, or systems that enable us to specify

which web sites
can take what types of actions on our computer.



Another aspect of web security specifies what information web sites can store on the
computer, to track our use of the web site.




Cookies



Cookies are messages that web servers pass to the web

browser when we visit
Internet sites.



The browser stores each message in a small file, called
cookie.txt
.



When we request another page from the server, the browser sends the cookie back to
the server.



These files typically contain information about our

visit to the web page, as well as
any information we've volunteered, such as the name and interests.



Cookies are most commonly used to track web site activity. When we visit some
sites, the server gives a cookie that acts as the identification card. Upon
each return
visit to that site, the browser passes that cookie back to the server.



In this way, a web server can gather information about which web pages are used the
most, and which pages are gathering the most repeat hits.

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Cookies are also used for onli
ne shopping. Online stores often use cookies that record
any personal information we enter, as well as any items in the electronic shopping
cart, so that user don't need to re
-
enter this information each time we visit the site.



Servers also use cookies to
provide personalized web pages. When we select
preferences at a site that uses this option, the server places the information in a
cookie. When we return, the server uses the information in the cookie to create a
customized page for us.



Security concerns i
n cookies

Only the web site that creates a cookie can read it. Additionally, web servers can
use only information that you provide or choices that you make while visiting the
web site as content in cookies.

Accepting a cookie does not give a server access
to the computer or any of the
personal information (except for any information that we may have purposely given,
as with online shopping). Servers can read only cookies that they have set, so other
servers do not have access to the information. Also, it is

not possible to execute code
from a cookie, and not possible to use a cookie to deliver a virus.



Platform for Internet Content Selection (PICS)



The
PICS

specification enables labels (metadata) to be associated with Internet
content.



It was originally des
igned to help parents and teachers control what children
access on the Internet, but it also facilitates other uses for labels, including code
signing and privacy.



The PICS platform is one on which other rating services and filtering software
has been bui
lt.



PICS

is a cross
-
industry working group whose goal is to facilitate the
development of technologies to give users of interactive media, such as the
Internet, control over the kinds of material to which they and their children have
access.



PICS members
believe that individuals, groups and businesses should have easy
access to the widest possible range of content selection products, and a diversity
of voluntary rating systems.



In order to advance its goals, PICS will devise a set of standards that facili
tate
the following:

1. Self
-
rating
:

Enable content providers to voluntarily label the content they create and
distribute.

2. Third
-
party rating
:

Enable multiple, independent labeling services to associate additional
labels with content created and dist
ributed by others. Services may devise
their own labeling systems, and the same content may receive different
labels from different services.

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3. Ease
-
of
-
use
:

Enable parents and teachers to use ratings and labels from a diversity of
sources to control the

information that children under their supervision
receive.



Content
-
Rating Services: Safesurf and RSAC (Recreational Sotware Advisory
Council)



The two rating systems that are built into Netscape Netwatch are Safesurf and
the Recreational Software Advisory
.



Microsoft’s Content Advisor includes only RSAC’s system.



Safesurf is a parents’ group trying to make the internet a safe and useful tool for
children.



RSAC is a nonprofit corporation and its mission was to issue a rating system for
computer games, and it

later extended its game
-
rating system to the Internet.

2.B.2 Discuss the Audio and video on the web



With the increased popularity of broadband connections, many sites features music,
movie, and television clips which can be viewed or download.



However th
e audio or video files are large in size and take a long time to download.



Since audio and video files are large, streaming was invented.



Streaming enables the computer to play the beginning of an audio or video file while
the rest of the file is still do
wnloading.



If the file arrives more slowly than the computer plays it, the playback has gaps
while the computer waits for more data to play.




Popular Audio and Video players



RealOne Player


plays most popular audio formats and video files, including
strea
ming audio and video. Supports burning audio files on CDs, so we can create
our own music CDs.



Quick Time


plays audio and video files stored in the Quicktime format.



Windows Media Player


plays both regular and streaming audio and video
files, including

most audio files and CDs. It supports burning to CDs or copying files
to portable media players that support WMA format.



WinAmp


plays MP3 and windows media files, as well as many other popular
music formats, CDs, and streaming audio.



MusicMatch


plays
MP3s and CDs, copies and creates CDs, transfers MP3s to
portable media players, and supports internet radio broadcasts.




Playing video on the Internet

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The video files are very large in size, meaning a video clip just a few seconds
long could take ten minut
es or more to download.



Even using streaming media, where the content is played as it is downloaded, the
images were often blocky and tiny.



With improved video compression techniques and faster internet connections the
rich multimedia content can be downlo
aded or played within seconds.



Prerecorded video

o

Several video formats are in use on the internet.

o

Many videos play in windows media player, whereas other videos require
RealOne player or Quicktime player.

o

We can view the prerecorded video clips using the
right player.



Live video with webcams

o

Another source for video broadcasts is the ever
-
popular webcam.

o

These are digital video cameras broadcast from a specific location

o

Webcam images are usually updated between every few seconds,
although some sites use st
reaming video for their webcams.

2.B.3. Explain the Web site Creation Concepts



Basic steps in Creating a site

1.

Plan the structure of the site, so that we have an idea what information will be on at
least the home page and other key pages.

2.

Using the text edi
tor or web page editor, create the pages of the site and save them as
HTML files. Use a graphics editor to create or view graphics for the pages.

3.

Using browser, view the HTML files created. Check the contents and the links

4.

Publish the web site by putting a
ll of its files on a web server.

5.

Using the browser, view the web pages as stored on the web server.

6.

Publicize the site, get feedback, get new ideas, and repeat the steps.




Planning the Site

The planning process involves answering these questions.

1.

Who is t
he audience for the site?

2.

What can you put on the site that will interest people?

3.

How can we make it easy for people to navigate the site?

4.

How the pages are stored on the site?

5.

What are the tools needed to develop the site?

Issues to be aware of when plann
ing the web site:

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1.

Text size

2.

Colors

3.

Writing for an international audience

4.

Privacy

5.

Maintenance

6.

Accessibility




Tools needed to develop the site

1.

Text

2.

Pictures

3.

Animated graphics

4.

Audio files

5.

Video files

6.

Animation files

7.

Forma and database information

8.

Text editor

9.

Drawing programs

10.

Clip art gallery

11.

Sound or video equipment

2.B.4.
H
ow can we Optimize web graphics?



Graphics File formats

1.

Vector images consist if lines and various shapes outlined and filled with colors
or shadings.

2.

Bitmap images consist of colored dots,
or pixels. Web documents commonly use
bitmap images in two formats: Graphics Interchange Format (GIF) and Joint
Photographic Experts Group (JPEG).




Common programs for creating GIF and JPEG files

Generally, Graphics programs are of three varieties:

1.

Paint a
nd photo programs


Enables to read different image files and customize them
for web use. Eg: Adobe Photoshop and Macromedia fireworks

2.

Illustration programs


focus on creating images, principally vector graphics and
have features for optimizing the bitmap

files. Eg: Adobe Illustrator and CorelDraw.

3.

Graphics Utilities

-


small programs with simple features that focus on converting
images from one format to another.

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Graphics program that are widely available:

1.

Microsoft Paint

2.

Adobe PhotoShop

3.

Adobe ImageReady

4.

Macromedia Fireworks

5.

Paint Shop Pro

6.

Lview pro




Optimizing Images

1.

The Best method to decrease file size for a WEB image is to decrease the quality.
This does NOT mean the image will not look good on a computer monitor.

2.

Digitized images are normally at a mu
ch higher quality (resolution / dots per inch)
than a monitor can display.

3.

This step alone will normally reduce the file size to 1/5 of the original. Physical size
will not change (Avoid resize until final step).

4.

The Second best method (optional) is to '
crop' off any 'dead' area. For example,
center the subject in the picture by cropping the borders.

5.

Using 'resize' to reduce file size is NOT very effective. (usually no more than 1/2 of
the original size
-

even if we take the viewing size below 320 x 240
:( Resize should
be used to obtain the 'physical' size you desire i.e resizing
-

Used alone results in an
image that is not really optimized very well.

6.

Minimize the image dimensions by using the smallest practical image height and
width.

7.

Minimizing or avo
iding certail types of Image content.

8.

Minimizing and flattening colors.


2.B.5. Explain the FTP and Peer
-
to
-
peer

File Transfer Protocol

(
FTP
) is a network protocol used to transfer data from one
computer to another through a network, such as the Internet.

FTP is a file transfer protocol for exchanging and manipulating files over any TCP
-
based
computer network. A FTP client may connect to a FTP server to manipulate files on that
server. As there are many FTP client and server programs available for different

operating
systems, FTP is a popular choice for exchanging files independent of the operating systems
involved.



Connection methods

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FTP runs exclusively over TCP. FTP servers by default listen on port 21 for
incoming connections from FTP clients. A connecti
on to this port from the FTP
Client forms the control stream on which commands are passed to the FTP server
from the FTP client and on occasion from the FTP server to the FTP client. FTP uses
out
-
of
-
band control, which means it uses a separate connection f
or control and data.
Thus, for the actual file transfer to take place, a different connection is required
which is called the data stream. Depending on the transfer mode, the process of
setting up the data stream is different.

In
active mode
, the FTP clien
t opens a dynamic port (49152

65535), sends the FTP
server the dynamic port number on which it is listening over the control stream and
waits for a connection from the FTP server. When the FTP server initiates the data
connection to the FTP client it binds

the source port to port 20 on the FTP server.

In order to use active mode, the client sends a PORT command, with the IP and port
as argument. The format for the IP and port is "h1,h2,h3,h4,p1,p2". Each field is a
decimal representation of 8 bits of the ho
st IP, followed by the chosen data port. For
example, a client with an IP of 192.168.0.1, listening on port 49154 for the data
connection will send the command "PORT 192,168,0,1,192,2". The port fields
should be interpreted as p1×256 + p2 = port, or, in th
is example, 192×256 + 2 =
49154.

In
passive mode
, the FTP server opens a dynamic port (49152

65535), sends the
FTP client the server's IP address to connect to and the port on which it is listening
(a 16 bit value broken into a high and low byte, like expl
ained before) over the
control stream and waits for a connection from the FTP client. In this case the FTP
client binds the source port of the connection to a dynamic port between 49152 and
65535.

To use passive mode, the client sends the
PASV

command to w
hich the server would
reply with something similar to "227 Entering Passive Mode (127,0,0,1,192,52)".
The syntax of the IP address and port are the same as for the argument to the PORT
command.

In
extended passive mode
, the FTP server operates exactly the
same as passive
mode, however it only transmits the port number (not broken into high and low
bytes) and the client is to assume that it connects to the same IP address that was
originally connected to. Extended passive mode was added by RFC 2428 in
Septem
ber 1998.

While data is being transferred via the data stream, the control stream sits idle. This
can cause problems with large data transfers through firewalls which time out
sessions after lengthy periods of idleness. While the file may well be successfu
lly
transferred, the control session can be disconnected by the firewall, causing an error
to be generated.

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The FTP protocol supports resuming of interrupted downloads using the REST
command. The client passes the number of bytes it has already received as

argument
to the REST command and restarts the transfer. In some commandline clients for
example, there is an often
-
ignored but valuable command, "reget" (meaning "get
again") that will cause an interrupted "get" command to be continued, hopefully to
compl
etion, after a communications interruption.

Resuming uploads is not as easy. Although the FTP protocol supports the APPE
command to append data to a file on the server, the client does not know the exact
position at which a transfer got interrupted. It has

to obtain the size of the file some
other way, for example over a directory listing or using the SIZE command.

The objectives of FTP,are:

1.

To promote sharing of files (computer programs and/or data).

2.

To encourage indirect or implicit use of remote compute
rs.

3.

To shield a user from variations in file storage systems among different hosts.

4.

To transfer data reliably, and efficiently.



Data format

While transferring data over the network, several data representations can be used.
The two most common transfer
modes are:

1.

ASCII mode

2.

Binary mode: In "Binary mode", the sending machine sends each file byte for
byte and as such the recipient stores the bytestream as it receives it. (The FTP
standard calls this "IMAGE" or "I" mode)

In "ASCII mode", any form of data
that is not plain text will be corrupted. When a
file is sent using an ASCII
-
type transfer, the individual letters, numbers, and
characters are sent using their ASCII character codes. The receiving machine saves
these in a text file in the appropriate form
at (for example, a Unix machine saves it in
a Unix format, a Windows machine saves it in a Windows format). Hence if an
ASCII transfer is used it can be assumed plain text is sent, which is stored by the
receiving computer in its own format. Translating be
tween text formats might entail
substituting the
end of line

and
end of file

characters used on the source platform
with those on the destination platform, e.g. a Windows machine receiving a file from
a Unix machine will replace the line feeds with carriag
e return
-
line feed pairs. It
might also involve translating characters; for example, when transferring from an
IBM mainframe to a system using ASCII, EBCDIC characters used on the
mainframe will be translated to their ASCII equivalents, and when transferri
ng from
the system using ASCII to the mainframe, ASCII characters will be translated to
their EBCDIC equivalents.

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By default, most FTP clients use ASCII mode. Some clients try to determine the
required transfer
-
mode by inspecting the file's name or content
s, or by determining
whether the server is running an operating system with the same text file format.

The FTP specifications also list the following transfer modes:

1.

EBCDIC mode
-

this transfers bytes, except they are encoded in EBCDIC rather
than ASCII. T
hus, for example, the ASCII mode server

2.

Local mode
-

this is designed for use with systems that are word
-
oriented rather
than byte
-
oriented.




FTP and web browsers

Most recent web browsers and file managers can connect to FTP servers, although
they may la
ck the support for protocol extensions such as FTPS. This allows
manipulation of remote files over FTP through an interface similar to that used for
local files. This is done via an FTP
URL
, which takes the form
ftp(s)
://
<
ftpserveraddress
>

(e.g.,
ftp://ftp.gimp.org/
). A password can optionally be
given in the URL, e.g.:

ftp(s)
://
<
login
>
:
<
password
>
@
<
ftpserveraddress
>:<
port
>.
Most web
-
browsers require the use of passive mode FTP, which not all FTP servers
are capable of handling. Some browsers allow only the downloading of files, but
offer no way to upload files to the server.



List of FTP commands

C
ommands used by the FTP client software as opposed to the user are often
described as
raw FTP commands
.



ABOR
-

Abort an active file transfer.



ACCT
-

Account information.



ALLO
-

Allocate sufficient disk space to receive a file.



APPE
-

Append.



CDUP
-

Cha
nge to Parent Directory.



CLNT
-

Send FTP Client Name to server.



CWD
-

Change working directory.



DELE
-

Delete file.



EPSV
-

Enter extended passive mode



EPRT
-

Specifies an extended address and port to which the server should
connect.



FEAT
-

Get the fe
ature list implemented by the server. GET
-

Use to download
a file from remote



HELP
-

Returns usage documentation on a command if specified, else a general
help document is returned.

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LIST
-

Returns information of a file or directory if specified, else i
nformation of
the current working directory is returned.



LPSV
-

Enter long passive mode.



LPRT
-

Specifies a long address and port to which the server should connect



MDTM
-

Return the last
-
modified time of a specified file.



MGET
-

Use to download multipl
e files from remote.



MKD
-

Make directory (folder).



MNT
-

Mount File Structure.



MODE
-

Sets the transfer mode (Stream, Block, or Compressed).



MPUT
-

Use to upload multiple files to remote.



NLST
-

Returns a list of filenames in a specified directory.



NOOP
-

No operation (dummy packet; used mostly on keepalives).



OPTS
-

Select options for a feature.



PASS
-

Authentication password.



PASV
-

Enter passive mode.



PORT
-

Specifies an address and port to which the server should connect.



PUT
-

Use to upload

a file to remote.



PWD
-

Print working directory. Returns the current directory of the host.



QUIT
-

Disconnect.



REIN
-

Re initializes the connection.



REST
-

Restart transfer from the specified point.



RETR
-

Retrieve (download) a remote file.



RMD
-

Re
move a directory.



RNFR
-

Rename from.



RNTO
-

Rename to.



SITE
-

Sends site specific commands to remote server.



SIZE
-

Return the size of a file.



SMNT
-

Mount file structure.



STAT
-

Returns the current status.



STOR
-

Store (upload) a file.



STOU
-

Sto
re file uniquely.



STRU
-

Set file transfer structure.



SYST
-

Return system type.



TYPE
-

Sets the transfer mode



UMNT
-

Unmount file structure.



USER
-

Authentication username



Peer
-
to
-
peer Architecture

Often referred to simply as peer
-
to
-
peer, or abbrevi
ated P2P, peer
-
to
-
peer
architecture is a type of network in which each workstation has equivalent
capabilities and responsibilities. This differs from client/server architectures where
some computers are dedicated to serving the others. Peer
-
to
-
peer networ
ks are
generally simpler but they usually do not offer the same performance under heavy
loads. The P2P network itself relies on computing power at the ends of a connection
rather than from within the network itself.

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P2P is often mistakenly used as a term
to describe one user linking with another user
to transfer information and files through the use of a common P2P client to
download MP3s, videos, images, games and other software. This, however, is only
one type of P2P networking. Generally, P2P networks a
re used for sharing files, but
a


P2P network can also mean Grid Computing or Instant messaging.



Types of P2P Networks

Peer
-
to
-
peer networks come in three flavors. The category classification is based on
the network and application.


Collaborative Computi
ng

Also referred to as distributed computing, it combines the idle or unused CPU
processing power and/or free disk space of many computers in the network.
Collaborative computing is most popular with science and biotech organizations
where intense computer

processing is required. Examples of distributed computing
can be found at GRID.ORG where United Devices is hosting virtual screening for
cancer research on the Grid MP platform. This project has evolved into the largest
computational chemistry project in
history. United Devices has harnessed the power
of more than 2,000,000 PCs around the world to generate more than 100 teraflops of
power. Most distributed computing networks are created by users volunteering their
unused computing resources to contribute t
o public interest research projects.

Instant Messaging


One very common form of P2P networking is Instant Messaging (IM) where
software applications, such as MSN Messenger or AOL Instant Messenger, for
example, allow users to chat via text messages in rea
l
-
time. While most vendors
offer a free version of their IM software others have begun to focus on enterprise
versions of IM software as business and corporations have moved towards
implementing IM as a standard communications tool for business.

Affinity
Communities


Affinity communities is the group of P2P networks that is based around file
-
sharing
and became widely known and talked about due to the public legal issues
surrounding the direct file sharing group, Napster. Affinity Communities are based
on u
sers collaborating and searching other user's computers for information and files.



How Peer
-
to
-
peer File
-
sharing Clients Work

Once you have downloaded and installed a P2P client, if you are connected to the
Internet you can launch the utility and you are t
hen logged into a central indexing
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server. This central server indexes all users who are currently online connected to the
server. This server does not host any files for downloading. The P2P client will
contain an area where you can search for a specific
file. The utility queries the index
server to find other connected users with the file you are looking for. When a match
is found the central server will tell you where to find the requested file. You can then
choose a result from the search query and your

utility when then attempt to establish
a connection with the computer hosting the file you have requested. If a successful
connection is made, you will begin downloading the file. Once the file download is
complete the connection will be broken.

A second
model of P2P clients works in the same way but without a central indexing
server.


In this scenario the P2P software simply seeks out other Internet users using
the same program and informs them of your presence online, building a large
network of computer
s as more users install and use the software.



P2P Security Concerns

One major concern of using P2P architecture in the workplace is, of course, network
security. Security concerns stem from the architecture itself. Today we find most
blocking and routing
handles by a specific server within network, but the P2P
architecture has no single fixed server responsible for routing and requests. The first
step in securing your P2P network is to adopt a strict usage policy within the
workplace. In securing your netw
ork against attacks and viruses there are two main
strategies where focus is on controlling the network access or the focus is put on
controlling the files. A protocol
-
based approach is where system administrators use a
software or hardware solution to wat
ch for and block intrusive network traffic being
received through the P2P clients. A second method of protection is a software
solution which would provide file surveillance to actively search for files based on
their type, their name, their signature or e
ven their content.




P2P at Work

P2P is not only popular with home users but many small business have come to rely
on this cost
-
effective solution for sharing files with co
-
workers and clients. P2P
promotes the ease of working together when you're not phys
ically located in the
same office. In just seconds updated files and data can be shared with peers and
confidential files can be blocked for security. Additionally, companies can also
block access to Internet music and video files to assist in maintaining
a work
-
oriented P2P network. Not only does this keep the company free and clear from legal
issues regarding music downloading and sharing but it also keeps the corporate
bandwidth usage down.


2.B.
6
.
E
xpalin the web design concepts with example.


Introducti
on to Web Design

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Rule: YOU are NOT the USER



Rule: USERS are NOT DESIGNERS



Rule: Design for the common user, but account for differences



Rule: A site’s execution must be close to flawless



Rule: Know and respect the Web and Internet medium constraints



R
ule: Visuals will heavily influence the user’s initial perception of site’s value



The Web Design Process



Suggestion: Always collect content before if at all possible




Rule: Visual Design should proceed in a top
-
down fashion from home page
to sub sectio
n pages and, finally, to content pages




Rule: Sites always have bugs, so test your site well



Rule: Testing should address all aspects of a site, including content, visuals,
function, and purpose




Rule: Site development is an ongoing process
-
plan, design
, develop, release,
repeat



Designing for Users



Suggestion: There are no generic people. Always try to envision a real person
visiting your site



Suggestion: Avoid using text, graphics, and backgrounds of similar hue



Suggestion: Avoid combining text and

backgrounds of similar saturation




Rule: Keep contrast high. Avoid using text and backgrounds of similar lightness



Suggestion: Keep contrast high. Avoid using busy backgrounds




Rule: Make sure colors that are meant to distinguish items like links are
s
ignificantly different in two ways in two ways, such as hue and lightness




Rule: Recognition is easier than recall, so don’t force users to memorize
information




Rule: Do not make visited links the same style or color or as unvisited
ones, as it forces t
he user to remember where they have been.




Suggestion: Limit groups of similar choices such as links to 5
-
9 items




Suggestion: Aim for memorization of only three items or pages sequentially




Rule: When response times such as page loads take more than 30
seconds,
try to provide your own feedback to the user such as a load
-
time progress
bar.




Rule: Time matters more to a user than bytes delivered




Rule: Sensory adaptation does occur on the web. If you want a user’s attention
you’ll have to vary things sig
nificantly and often




Rule: Minimize mouse travel distance between successive choices




Rule: Minimize mouse travel between primary page hover locations and the
browser’s back button




Rule: Make click able regions large enough for users to move to them q
uickly
and press the accurately



Rule: Do not stray from the common interface conventions established by
heavily used sites

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Suggestion: Perform user testing early and often




Suggestion: Practice “Las Vegas” Web design. Provide the user with a
pleasant ex
perience complete with perks and the illusion of unlimited
choices, but control the situation strictly at all times

Site Types and Architectures



Premise: A web site’s logical structure is more important to a user than its
physical structure



Suggestion: A
im for a site click depth of three




Premise: The more important the page, the more redundant links should be
provided to it




Suggestion: Redundant links in a site should be no more than 10
-
20 % of the
page’s total exit links




Premise: Novice users prefe
r sites with predictable structure and may put up
with extra clicks or lack of control to achieve a comfortable balance




Premise: Power users or frequent site users want control and will favor
structures that provide more navigation choices



Navigation
Theory and Practice



Rule: Use simple and memorable URLs to improve navigation



Rule: Use consistent and explicit page labels for all page in a site




Rule: Site wide labeling icons or words such as the organization name or
logo should always return a user
to the home page of the site when clicked




Suggestion: When using color
-
coding to imply section location, make
sure the colors used are significantly different from each other




Rule: Avoid links named simply “back”. Always explicitly indicate where a
bac
k link will go



Rule: Avoid creating pages that cannot be backed out of easily using the
browser back button




Rule: Users remember their start page as a permanent landmark and the home
page of a visited web site and a semi
-
permanent landmark. Because of t
his,
these pages should be stable in their presentation but look noticeably different
than other pages visited.




Suggestion: Avoid placing primary navigation on the far right of the screen



Rule: Placement of navigation should be consistent within page la
yout




Suggestion: when separating navigation choices by position onscreen,
understand that four locations is a hard barrier




Suggestion: Minimize the distance between primary site navigation buttons and
the back button



Suggestion: Always attempt to limi
t mouse movement between subsequent
navigation items




Suggestion: When using frames, make smaller frames control larger adjacent
frames



Rule: Limit scrolling and mouse travel in navigation as much as possible



Rule: Consider a maximum of three page loads

before a result


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Linking: Text, Buttons, Icons, and Graphics




Suggestion: Always provide texture textual links at the bottom of pages
when using long pages with graphical buttons




Suggestion: When using image maps, always provide a secondary navigation

from such as text links



Rule: Avoid changing link colors



Rule: Avoid underlining non
-
linked text in web documents
-
use italics or bold
instead




Suggestion: Make sure to indicate if the link will jump them within a page,
within a site, or external site.
Don’t hide the URL, in case the user can deduce
the answer from it




Suggestion: Avoid changing visited link colors.



Suggestion: Avoid changing visited link colors




Suggestion: Add the last modification date to show update times and, where
necessary use
a New icon




Rule: Broken links should be considered catastrophic failures

Search and Design



Rule: Do not design pages solely to attract search engines as, ultimately, pages
are for people




Rule: If a site is filled with regular formatted data, very comp
lex to digest
data, or contains more than 100 pages, include a local search engine




Suggestion: When search is available in a site, include a search button or field
on all pages



Suggestion: When search is available in a site, include a search button or f
ield
on all pages



Suggestion: It is better to limit search to a topic, category, or idea rather than a
section of a site




Rule: Negative search result pages must include information on why a query
failed, and, potentially, how to fix the query





Page
Types and Layouts



Rule: Avoid wide pages, particularly those that cause rightward scrolling



Rule: Try to keep important items such as navigation in the first screen




Suggestion: Allow the user to stretch or shrink pages at will. Do not force
pages to fil
l to an available resolution unless layout will be lost without the
size increase




Suggestion: try to fit content vertically within 3
-
5 screens, if possible



Suggestion: Provide an obvious link to quickly skip a splash page



Rule: A home page should load
fast, but be dramatic enough to encourage
interest




Rule: A home page should clearly indicate what’s inside a site



Rule: Sub
-
pages should follow the style and navigation of the home page, at
least in spirit.


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Suggestion: make FAQ pages a single document

so they are easily printable,
if they are of reasonable length




Provide a link back to the top of the document or to the list of the question at
the end of every answer




Suggestion: Add a last modification indication to pages




Suggestion: inform users
that printed pages will be different than what is
seen onscreen or show the print version directly




Suggestion: use Acrobat PDF files for highly complex financial or mathematical
information




Suggestion: Clearly indicate Acrobat files with text and an ic
on, and provide
information on using these files




Suggestion Provide a way back to the site from an exit page



Rule: let users leave in peace Avoid “please don’t go” or “last chance” pop
-
up
windows




Suggestion: Avoid unconventional or very artistically o
riented interfaces
designs on task
-
driven of frequent
-
use sites




Rule: strive always in web design to be the same, but different



Text



Rule: increase line height to improve online text readability




Suggestion: Consider three font per page: one for page

labels and headlines
one for body, and one for navigation




Rule: always use white space to complement the use of information



Suggestion: be careful of using words that have alternate web meanings

Colors, Images, and Backgrounds




Rule: to ensure the app
ropriate color is produced, always use a hexadecimal
value over a named color except in the case of basic colors like white, black,
red, and so on




Rule Always store your images in a separate directory




Rule: Name your images in a logical fashion that gr
oups them by purpose or
usage



Rule: you can’t use the <img> tag without the SCR attribute




Suggestion: ALT text should reinforce the meaning of significant images; if
an image does not convey essential meaning, leaving the ALT value blank is
better than
cluttering the page with unnecessary tool tips




Rule: Always use the HEIGHT and WIDTH attributes with the <IMG> tag




Rule: NEVER use the HIEGHT and WIDTH attributes to resize images
with HTML. If a smaller version of a image is needed, create a smaller
v
ersion of the image and use HEIGHT and WIDTH correctly



Building Interactivity Using GUI Features



Suggestion: Use Alerts to inform the user of important issues, not general
information




Suggestion: Use a confirmation dialog to verify the execution of an

irreversible
or important task such as form submission


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Suggestion: use prompt dialogs only to ask a user to provide a short word or
numeric answer to a simple question. Do not ask questions that would result in
a multiple
-
line answer




Rule: Never allow

password fields to scroll



Rule: Limit the length of password fields to match password sizes




Rule: Do not use default values with password fields



Rule: Always check an initial radio button by default



Rule: use radio buttons for yes/no questions rather

than pull
-
down menus or
check boxes



Suggestion: Avoid move than eight items in a radio group




Suggestion: Use pull
-
downs if more than eight items are in a selection of one
-
choice
-
of
-
many to save screen real estate, as started by this rule




Rule: Do not

use radio buttons for navigation




Rule: Provide a confirmation on a form reset button to avoid accidents



Suggestion: Consider moving your reset button away from the submit button




Suggestion: Keep the submit button at the bottom of the form, either on
the
center or on the left side




Rule: Make forms keyboard friendly



Rule: Validate forms from the client side when possible

Web Technologies and Their Effect on Web Design



Rule: Do not use bleeding
-
edge web technology without good reason



Suggestion: Pic
k a casing style for HTML and stick with hit




Suggestion: Be careful with casing of attribute values, particularly with file
names



Rule: Validate all HTML pages



Suggestion: Use comments in HTML documents



Suggestion: Create and use page templates



Sugge
stion: Make sure to test to see if a script works in all versions of the
language



Rule: Always add an error handler for JavaScript




Rule: When trying to draw attention, avoid continuously running animation
loops




Suggestion: Don’t assume audio support.
Always provide alternative forms
of access for important audio based content such as a text transcript




Rule: Always allow a user to turn off continuously playing playing sounds



Suggestion: Avoid video use unless the message is improved in this medium.



Site Delivery and Management




Rule: The amount of bytes delivered to create a page is not as important as how
fast the user perceives the page to be




Suggestion: Provide numerous domain name forms for a site




Suggestion: Don’t skimp on Web server hardw
are and focus an systems with
high
-
speed hard drives, a great deal of memory, and good network interfaces




Suggestion: Choose to host your own Web site when security or control is a
primary concern




Suggestion: Avoid using underscores in filenames. Consi
der using dashes or no
MC9235

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space between words




Suggestion: Do not use mixed or uppercase letters in file or directory names




Rule: Check site links constantly




Suggestion: Check regularly for page details including spelling, legal terms,
and font usage. Pe
rform a print test if necessary




Suggestion: Provide the address web@yourdomainname.com for users to
contact you with suggestions and error reports




Suggestion: Do not put a visible page counter on your site



Rule: If your content is in any questionable,

have it PICS rated



The Future of Web Design



Prediction: HTML will still be around in some form or another for a great
while



Prediction: Downloadable fonts will become commonplace




Basic Web Design Concepts:


I have been evaluated some existing E
-
co
mmerce and E
-
business website's selling
numerous products and services online.. And found out some basic web designing
strategies and concepts. This document is sharpened by Wikipedia and some online
resources. This Information’s & Designs conducted a usab
ility of everyone.


Different of Mark
-
up Languages & Scripting languages:


Mark
-
Up Language

Scripting Language

*It is simply, built a set of tags. It is design for

*It is a higher level programming language.

definition, processing & Presentation of tex
t. (Ex:

*It is form of the programming language.& also
interpreted

Words, sentences, paragraphs), Tags are use to

Mark

at run
-
time.

UP
”,

*Text can be logically arranged, labelled.

*Compiled by the computer’s processor as other
=
䑯a畭敮琠ua渠⁢e⁶楥=e搠d
猠s⁰污楮⁴數琠潲⁶楥ted
=
灲潧pa浭楮iang畡ge猠⡃†E⁃HH⤬†⁔桡琠敶ery=瑩浥m
睡湴
=
瑨牯畧栠h⁢牯=獥爮
=
瑯⁲畮⁴桥t灲pg牡洬⁡⁳epa牡瑥⁰牯g牡洠湥e摳⁴漠牥a搠
瑨t
=
⩔桥=
mark
-
up

language specifies codes for
formatting

code, interpret it, and then follow the ins
tructions in
the

in layout & style within text file. The code familiar
with

Code. Compiled code has already been interpreted in
to

specify the formatting, called
tags.

machine language


*It is use to create graphical user interfaces & forms,
also


use
search engines .
Ex:

e
-
mail & e
-
Commerce


*There is two types of scripting language, client
-
side

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scripting language & server
-
side scripting language.


* This type languages commonly used to add
functionality


to a Web pages.


*Scripting Languages are
little bit slower

Ex: * HTML: Hypertext Mark
-
up Language.

Ex: JavaScript, PHP ,VBScript, Jscript ,Python

*XML: Extensible Mark
-
up Language.


This is a very simple & very Flexible Language.
This


text format derived from SGML (ISO 8879)






About Web

Standards:


Here are the definitions of the
W3C standards

(World Wide Web Consortium)




HTML


Hyper text Markup Language



This is a language it is been used for
creating documents on the web &

also HTML is a plain language.




CSS
-

Cascading style sheets.

CSS is used in conjunction with HTML to control
how to web pages are presenting



.It is a different language from HTML; HTML defines a structure & content of
the document. But CSS controls the presentation on the web page.




XML
-

Extensible Markup Langu
age, This language is use to create another
Markup Languages. Most of this

type languages using today. XML content
very easily to be shared across the applications.



XHTML
-

This language is re
-
write of HTML as an XML

,
XHTML
language elements

should

be lower case
&

closing tags.

(Ref: 002)




Web Authoring Tools:


Features of Web Authoring Tools.


(1).


(a)Most of Web Authoring Software’s has been provided multiple views of the web pages.
Those are

Standards & Normal or Design
view. It is the defau
lt view, similar to word processing
screen.

(b).The
Code

view is allow viewing HTML code & also allows work directly with HTML
code.

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(c).The
split

is both of views are displayed simultaneously in different windows.


Ex: *Macromedia Dreamweaver
-
Can witch be
tween
the View menu. *Microsoft FrontPage


I personally use above 2 software.


(2).


(a)
Creating Headings & Sub Headings
.


In the default view (Normal or design view) it is similar to word processing software’s.
More toolbars appear in top of the applicat
ion window .Ex: Formatting toolbar, its include
many buttons for formatting text, as Bold, Italic, & more..


Ex: (a) Macromedia Dreamweaver

Formatting Toolbar:









(b).Microsoft Front Page


Formatting Toolbar:



























(3). Inse
rt sub links:

Most of web authoring products, Insert menu appear
link

or
hyperlink

button. Click in
this button prompting linking text destination of the link want to display. And most of
authoring tools has a quick insert link.




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(
4). Insert Images:


Most of authoring tools software’s, Insert menu is appearing Add in Image Button.
Using this can insert image or Picture into the web page.


Key ideas of evaluation web sites.:


There are 6 key ideas in web sites evaluation process,

as followings,




Purpose :
Determine whether the main purpose of the site (Topic) is to inform or to
persuade





Author :
Author has appropriate education, training & his experience to write with
authority on the



identified topic.



Content :

Consider whether content seems biased. Look for documentation & point
of view.


Currency :
We are looking for the most updated (newest) information’s on the topic
& be sure to determine

when all the new information’s were added.



Coverage :
Shop arou
nd for the best source. We can compare all other e
-
commerce

al
web site’s to see which

one


Provides the better coverage. (Anyone in the world can buy & access.)



Basic Rules of web Design:


**
There are

5 basic rules
of web site design


Rules are.....,



.Web site should be easy to read. (This is the most important rule in web design)



.Web site should be easy to navigate.



.Web site should be easy to find.


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.Web page layout & design should be consistent throughout the entire site.



. Web site should b
e easy & quick to download.


Ex:
-


www.orayans.com, www.cargillsceylon.co
m




But there are several usability issues which should be addressed if the some sites
are to achieve its goals



Navigation.


Refers to th
e ability to find one’s way within the web site. Navigation is particularly very
important on the internet.



** Functionality


Refers to the support of all the activities which may be carried out on the web site.


**Control


Customers should feel that the
y are always in control of the interaction.


**Feedback


Refers to the provision of information about what is happening at any time.


**Consistency:


Consistency is important to use language and visual cues in a manner that is
both internally consistent an
d Consistent with general practice.


Usability evaluation check list for web sites:


(a).
Navigation

: Clear identification of current locations, Clearly identified link to
the home Page, Major parts of the site can access & display
on the Home page, Site d
esign structure is simple.


(b).
Functionality

:
All functionality clearly labelled, No necessary plug
-
ins care used ,

All


necessary functionality is available without leaving the site.

(c).
Control

:
User can cancel all operation, Clear exit point in ev
ery page, Page size


is less than 50Kb/page, All appropriate browsers are supports, Site

supports to users workflow.


(c).
Language :

Language is used simple.


(d).
Feedback:

Always clear what is happing on the Site, Users can receive e
-
mail feed back, All

feedback prompt, Users are informed if a
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plug
-
ins or browser version required, Users can send a feedback
via e
-
mail, or using feedback forms.


(e).
Consistency :

Only one word or term used to describe any item, Links match the
titles of the page to which
they refer, Stranded colours are used
for links & visited links.


(f).
Visual Clarity :

Layout is clear, There is sufficient write space, unnecessary animation
is avoided.


(g).
Error prevention & correction:

Errors do not occur unnecessarily, Error
massag
es are in the plain language. Error
massage describe what action is necessary,
Error massage provide a clear exit point


2.B.7. Explain the concept of downloading and Installing software.



To Download the Java software and Install in the computer.

Steps:

Step 1:


Visit java.sun.com.

Step
2:
Find a link to download the Java SE 6 (the Java Standard Edition, version 6).


If user find some other version. Just make sure that user have a version numbered
6 or higher.

Step
3:
Download the JDK, n
ot the JRE.


To create user own Java programs, user need more than the JRE. User need the
entire JDK.

Step 4:
Double
-
click the icon of the downloaded file and follow the wizard's instructions
for installing the


JDK.



User can choose t
o have some or all of the components installed. Just make
sure that user choice includes the development tools and the JRE.



User also sees the name of the directory in which the JDK is to be installed.
Jot down the exact name of the directory.



At some poi
nt, the wizard asks whether user want to register user Web
browser with the latest Java plug
-
in.

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Step 5:
Return to the page where user found the JDK download. Get another download


the Java SE


Documentation (also known as the Java SE

API Documentation).

Step 6:
Extract the zipped Java SE Documentation to user Java home directory.

After user downloads the Java JDK, users are ready to install the software on user
computer. The following steps offer some guidelines:

1. Open My Computer a
nd find the JDK file that user downloaded.

The file has a name like jdk
-
6
-
.exe.

2. Double
-
click the JDK file's icon.

• If user downloaded the tiny online installation file, user computer downloads
more files from the Internet and installs Java while it dow
nloads.

• If user downloaded the huge offline installation file, user computer extracts the
contents of the huge setup file and installs Java from these contents.

3. Among the features those users select to install, make sure user select
Development Tools
and Public Java Runtime Environment.

User can choose to have some or all of the components installed. Just make sure
that user choice includes these two items. To select or un
-
select an item, click the
icon to the left of the item's name.

4. Jot down the n
ame of the directory in which the Java SDK is being installed and
then click Next.

From one version to the next, the installation package puts Java in different
directories on the computer's hard drive. Lately the package has installed Java in
a directory
named C:
\
Program Files
\
Java
\
jdk1.6.0. During the installation on user
computer, user may see a different directory name.

5. Enjoy the splash screens that user see while the software is being installed.

At the end of the installation, user clicks the prove
rbial Finish button. But users
are still not done with whole kit 'n caboodle. The next step is installing the Java
documentation.

6. Copy the documentation to user Java home directory.

7. Check to make sure that user unzipped the documentation correctly.

A
fter unzipping the documentation's Zip file, user should have a subdirectory
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named docs in user Java home directory. So open My Computer and navigate to
user new jdk whatever folder. Directly inside that folder, user should see a new
folder named docs. Thi
s directory is called user Java doc directory.

When user docs are all lined up in a row, user can proceed to the next step


installing a Java development environment.














Website








UNIT


III



Part A

3.A.1.Explain the fe
atures of JAVA.

The basic features that make Java a powerful and popular programming language
are:



Platform Independence

o

The Write
-
Once
-
Run
-
Anywhere ideal has not been achieved (tuning for
different platforms usually required), but closer than with other
languages.



Object Oriented

o

Object oriented throughout
-

no coding outside of class definitions, including
main().

o

An extensive class library available in the core language packages.



Compiler/Interpreter

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o

Code is compiled to bytecodes that are interpreted

by Java virtual machines
(JVM).

o

This provides portability to any machine for which a virtual machine has
been written.

o

The two steps of compilation and interpretation allow for extensive code
checking and improved security.



Robust

o

Exception handling bui
lt
-
in, strong type checking (that is, all data must be
declared an explicit type), local variables must be initialized.



Several dangerous features of C & C++ eliminated:

o

No memory pointers

o

No preprocessor

o

Array index limit checking



Automatic Memory Man
agement

o

Automatic garbage collection
-

memory management handled by JVM.



Security

o

No memory pointers

o

Programs run inside the virtual machine sandbox.

o

Array index limit checking