Saturday, 3 December 2011

C-DIT DCA Reference Questions and Answers - Html & Internet

By on 23:22

Difference Between Html & XML

XML was designed to transport and store data.
HTML was designed to display data.

XML stands for EXtensible Markup Language
XML is a markup language much like HTML
XML was designed to carry data, not to display data
XML tags are not predefined. You must define your own tags
XML is designed to be self-descriptive
XML is a W3C Recommendation

XML is not a replacement for HTML.

XML and HTML were designed with different goals:

XML was designed to transport and store data, with focus on what data is
HTML was designed to display data, with focus on how data looks

HTML is about displaying information, while XML is about carrying information.

Maybe it is a little hard to understand, but XML does not DO anything. XML was created to structure, store, and transport information.

The following example is a note to Tove, from Jani, stored as XML:
<body>Don't forget me this weekend!</body>

The note above is quite self descriptive. It has sender and receiver information, it also has a heading and a message body.

But still, this XML document does not DO anything. It is just information wrapped in tags. Someone must write a piece of software to send, receive or display it.
With XML You Invent Your Own Tags

The tags in the example above (like <to> and <from>) are not defined in any XML standard. These tags are "invented" by the author of the XML document.

That is because the XML language has no predefined tags.

The tags used in HTML are predefined. HTML documents can only use tags defined in the HTML standard (like <p>, <h1>, etc.).

XML allows the author to define his/her own tags and his/her own document structure.
XML is Not a Replacement for HTML

XML is a complement to HTML.

It is important to understand that XML is not a replacement for HTML. In most web applications, XML is used to transport data, while HTML is used to format and display the data.

My best description of XML is this:

XML is a software- and hardware-independent tool for carrying information.
XML is a W3C Recommendation

XML became a W3C Recommendation on February 10, 1998.

XML is now as important for the Web as HTML was to the foundation of the Web.

XML is the most common tool for data transmissions between all sorts of applications.

Html Tags              Description                            DTD

<!--...-->                   Defines a comment                               STF
<!DOCTYPE>         Defines the document type STF
<a>                          Defines an anchor                                STF
<abbr>                     Defines an abbreviation        STF
<acronym>             Defines an acronym              STF
<address>              Defines contact information for the author/owner of a document    STF
<applet>                                 Deprecated. Defines an embedded applet         TF
<area />                   Defines an area inside an image-map                STF
<b>                          Defines bold text   STF
<base />                 Defines a default address or a default target for all links on a page                STF
<basefont />           Deprecated. Defines a default font, color, or size for the text in a page          TF
<bdo>                     Defines the text direction     STF
<big>                       Defines big text      STF
<blockquote>         Defines a long quotation      STF
<body>                   Defines the document's body              STF
<br />                       Defines a single line break   STF
<button>                                 Defines a push button           STF
<caption>               Defines a table caption         STF
<center>                                 Deprecated. Defines centered text      TF
<cite>                      Defines a citation STF
<code>                   Defines computer code text                 STF
<col />                     Defines attribute values for one or more columns in a table             STF
<colgroup>            Defines a group of columns in a table for formatting        STF
<dd>                       Defines a description of a term in a definition list             STF
<del>                       Defines deleted text              STF
<dfn>                      Defines a definition term      STF
<dir>                       Deprecated. Defines a directory list    TF
<div>                       Defines a section in a document         STF
<dl>                         Defines a definition list         STF
<dt>                         Defines a term (an item) in a definition list         STF
<em>                       Defines emphasized text      STF
<fieldset>                Defines a border around elements in a form      STF
<font>                     Deprecated. Defines font, color, and size for text              TF
<form>                    Defines an HTML form for user input STF
<frame />                 Defines a window (a frame) in a frameset           F
<frameset>              Defines a set of frames         F
<h1> to <h6>          Defines HTML headings       STF
<head>                   Defines information about the document            STF
<hr />                      Defines a horizontal line      STF
<html>                     Defines an HTML document                 STF
<i>                           Defines italic text   STF
<iframe>                 Defines an inline frame         TF
<img />                    Defines an image STF
<input />                                 Defines an input control       STF
<ins>                       Defines inserted text             STF
<kbd>                      Defines keyboard text           STF
<label>                    Defines a label for an input element    STF
<legend>                                Defines a caption for a fieldset element              STF
<li>                          Defines a list item STF
<link />                    Defines the relationship between a document and an external resource       STF
<map>                     Defines an image-map          STF
<menu>                   Deprecated. Defines a menu list          TF
<meta />                 Defines metadata about an HTML document      STF
<noframes>            Defines an alternate content for users that do not support frames TF
<noscript>              Defines an alternate content for users that do not support client-side scripts              STF
<object>                 Defines an embedded object               STF
<ol>                         Defines an ordered list         STF
<optgroup>            Defines a group of related options in a select list             STF
<option>                                 Defines an option in a select list         STF
<p>                          Defines a paragraph             STF
<param />               Defines a parameter for an object        STF
<pre>                      Defines preformatted text     STF
<q>                          Defines a short quotation     STF
<s>                          Deprecated. Defines strikethrough text              TF
<samp>                   Defines sample computer code           STF
<script>                 Defines a client-side script STF
<select>                 Defines a select list (drop-down list) STF
<small>                   Defines small text STF
<span>                   Defines a section in a document         STF
<strike>                   Deprecated. Defines strikethrough text              TF
<strong>                                 Defines strong text                STF
<style>                    Defines style information for a document           STF
<sub>                      Defines subscripted text       STF
<sup>                      Defines superscripted text   STF
<table>                    Defines a table       STF
<tbody>                 Groups the body content in a table     STF
<td>                         Defines a cell in a table         STF
<textarea>               Defines a multi-line text input control                 STF
<tfoot>                    Groups the footer content in a table   STF
<th>                         Defines a header cell in a table            STF
<thead>                 Groups the header content in a table                 STF
<title>                      Defines the title of a document            STF
<tr>                          Defines a row in a table        STF
<tt>                          Defines teletype text              STF
<u>                          Deprecated. Defines underlined text   TF
<ul>                         Defines an unordered list     STF
<var>                       Defines a variable part of a text            STF
<xmp>                     Deprecated. Defines preformatted text

What is Internet

The internet in simple terms is a network of the interlinked computer networking worldwide, which is accessible to the general public. These interconnected computers work by transmitting data through a special type of packet switching which is known as the IP or the internet protocol.

Internet is such a huge network of several different interlinked networks relating to the business, government, academic, and even smaller domestic networks, therefore internet is known as the network of all the other networks. These networks enable the internet to be used for various important functions which include the several means of communications like the file transfer, the online chat and even the sharing of the documents and web sites on the WWW, or the World Wide Web.

It is always mistaken said that the internet and the World Wide Web are both the same terms, or are synonymous. Actually there is a very significant difference between the two which has to be clear to understand both the terms. The internet and World Wide Web are both the networks yet; the internet is the network of the several different computers which are connected through the linkage of the accessories like the copper wires, the fiber optics and even the latest wireless connections. However, the World Wide Web consists of the interlinked collection of the information and documents which are taken as the resource by the general public. These are then linked by the website URLs and the hyperlinks. Therefore World Wide Web is one of the services offered by the whole complicated and huge network of the internet.

The use of IP in the Internet is the integral part of the network, as they provide the services of the internet, through different layers organization through the IP data packets. There are other protocols that are the sub-classes of the IP itself, like the TCP, and the HTTP.

What is Formal Learning, Non-Formal Learning and In-Formal Learning?

 Formal learning consists of learning that occurs within an organised and structured context (formal education, in-company training), and that is designed as learning. It may lead to a formal recognition (diploma, certificate).
Formal learning is intentional from the learner’s perspective

 Non-formal learning consists of learning embedded in planned activities that are not explicitly designated as learning, but which contain an important learning element. Non-formal learning is intentional from the learner’s point of view. The term non-formal has been used most often to describe organized learning outside of the formal education system. These offerings tend to be short-term, voluntary, and have few if any prerequisites.

 Informal learning is defined as learning resulting from daily life activities related to work, family, or leisure. It is often referred to as experiential learning and can to a certain degree be understood as accidental learning.
It is not structured in terms of learning objectives, learning time and/or learning support. Typically, it does not lead to certification. Informal learning may be intentional but in most cases, it is non-intentional (or ‘incidental’/random).

Authentication and authorization

Authentication and authorization is the key to gain access to the corporate resources – many types of authentication methods you can adopt with their advantages and disadvantages

In a corporate network infrastructure, the information assets must be properly protected against any types of threats or security breaches. The need of management of information security is very essential for the organization. The way the user gain access to the corporate network either in the Ethernet network or the wireless network – use the authentication and authorization methods.

Authentication is the process where a user (via any type of physical access such as computer, network, or remote) establishes a right to an identity. A user log in to a network infrastructure system with a user name and password, and the system knows who the user is.

Authorization is the process of determining whether a user is permitted to perform some action or access to a resource. A user log in to a system with a user name and password, and the system knows who the user is and the user can grant or deny access to certain network resources.


There are many different methods that can be used to authenticate a user.

User name and password Authentication

Most operating systems and web servers will have some type of user name and password authentication system. Most of these systems will have some type of mechanism to manage the user name and password architecture—for example, account expiration, password expiration, password length, and/or quality of password. Currently, this is the access method of choice for most pages on the Internet. See also password security guidelines.


Easy to implement and manage
Inexpensive—provided with most operating systems and web servers
Only minimal training required for end users


User name and password sent in the clear text for basic authentication (although not in all cases, and SSL can encrypt at the Network level)
User name and password subject to directory attacks
On the Internet, users may have many different user names and passwords (which can be a real headache to maintain)

Certificates Authentication

User certificates can be used by end users to assure their identity. Access to the certificate is normally controlled by a password that is local to the certificate. For example, on Netscape you can open the certificate database with a password, which then allows you to use the certificate. Many companies are starting to implement user certificates on their internal network.


Binds the certificate to the user
Ability to encrypt data and digitally sign messages
Supported by most web browsers and e-mail packages
Offers some mechanisms for a single sign-on solution
Difficult to stage a directory attack
Allows roaming users, i.e., users moving from one location to another (if your vendor supports this feature)
Can encrypt data, e-mail, and sign with only one certificate (actually, it is better to have separate certificates for signing and encryption)


Cost—implementing a PKI can be expensive
Extensive user training is required
Requires a support structure
Roaming users, i.e., users moving from one location to another (not many vendors support this feature—but this is getting better)
Vendors are only now developing tools that can handle large-scale implementations

See also windows file encryption.

Biometric techniques Authentication

A biometric authentication system will use devices such as fingerprints or eye scanners to allow access. This type of device can ensure greater security for high-risk environments that need to limit and control access to sensitive systems. Using this type of system, you could limit “tailgating,” or, allowing users to use another person’s user name and password.


The person is the authentication—very difficult to impersonate
Directory attacks are nearly impossible
Offers some mechanisms for a single sign-on solution


Not many vendors support this technology, but the laptops today are now equipped with this type of fingerprint authentication to gain access to the laptops.
Expensive to implement unless manufactured in mass production such as today’s laptops

Smart cards Authentication

A smart card is typically a credit card-sized plastic card that has an embedded integrated circuit (IC) chip. This chip is what makes the card “smart.” The smart card can store all types of information, which can be transferred via an electronic interface that connects to a computer. This smart card can store information about who you are and cryptographic keys and perform cryptographic algorithms, like encryption. Access to the smart card is controlled via a PIN or a password. This type of authentication mostly deployed for door access in high security area such as military, banks, gold industry, etc.


Easy to bind the card to the person
The card can hold keys and other information about the user
If keys are included, then it is easy to encrypt data and e-mail
Easy to train users on the technology
Great solution for roaming users; the certificate can easily be transported


Very expensive, although the cost of this technology is dropping
Still easy to give the card and PIN to another user i.e. tailgating
Requires a support system and may require more hardware on each PC

Anonymous Authentication

An anonymous user name is a method for giving users access to files so they don’t need to identify themselves to the server. The user enters “anonymous” as a user ID. Anonymous identification is a common way to get access to a server to view or download files that are publicly available.

Through the use of a control anonymous setting, anonymous is both an authentication method and an authorization method. By accessing a system via a control anonymous setting, you can be sure that you know where users are and what data they are accessing. Never assume that anonymous should be a “default” access. This is dangerous. Make sure you limit anonymous access to the data sources that really need to gain access.


Easy to implement
Little to no user training required
Ability to conduct secure transactions without registering a user with a user name and password. How? Have you ever purchased a book online and used a credit card? Not all companies will require you to create an account. All you need to do is enter your credit card information (and hopefully you used SSL!)


Clearly, there is no binding to a specific user. Consequently, you don’t know who accessed the data
Cannot block access on a “per-user” basis
Potentially open to “spam” attacks, where garbage is dumped onto your site
No logging or audit trail **********

What is Ecommerce?

In its simplest form ecommerce is the buying and selling of products and services by businesses and consumers over the Internet. People use the term "ecommerce" to describe encrypted payments on the Internet.

Sometimes these transactions include the real-time transfer of funds from buyer to seller and sometimes this is handled manually through an eft-pos terminal once a secure order is received by the merchant.

Internet sales are increasing rapidly as consumers take advantage of lower prices offer by wholesalers retailing their products. This trend is set to strengthen as web sites address consumer security and privacy concerns.

Let's Talk - What is ecommerce?
Benefits of E-Commerce

E-commerce can provide the following benefits over non-electronic commerce:

Reduced costs by reducing labour, reduced paper work, reduced errors in keying in data, reduce post costs
Reduced time. Shorter lead times for payment and return on investment in advertising, faster delivery of product
Flexibility with efficiency. The ability to handle complex situations, product ranges and customer profiles without the situation becoming unmanageable.
Improve relationships with trading partners. Improved communication between trading partners leads to enhanced long-term relationships.
Lock in Customers. The closer you are to your customer and the more you work with them to change from normal business practices to best practice e-commerce the harder it is for a competitor to upset your customer relationship.
New Markets. The Internet has the potential to expand your business into wider geographical locations.

Types of Ecommerce
Ecommerce can be classified based on the type of participants in the transaction:

Business to Business (B2B)
B2B ecommerce transactions are those where both the transacting parties are businesses, e.g., manufacturers, traders, retailers and the like.

Business to Consumer (B2C)
When businesses sell electronically to end-consumers, it is called B2C ecommerce.

Consumer to Consumer (C2C)
Some of the earliest transactions in the global economic system involved barter -- a type of C2C transaction. But C2C transactions were virtually non-existent in recent times until the advent of ecommerce. Auction sites are a good example of C2C ecommerce.

Online Shopping
Buying and selling goods on the Internet is one of the most popular examples of ecommerce. Sellers create storefronts that are the online equivalents of retail outlets. Buyers browse and purchase products with mouse clicks. Though is not the pioneer of online shopping, it is arguably the most famous online shopping destination.

Electronic Payments
When you are buying goods online, there needs to be a mechanism to pay online too. That is where payment processors and payment gateways come into the picture.

Electronic payments reduce the inefficiency associated with writing and mailing checks. It also does away with many of the safety issues that arise due to payment made in currency notes.

Online Auctions
When you think online auction, you think eBay. Physical auctions predate online auctions, but the Internet made auctions accessible to a large number of buyers and sellers. Online auctions are an efficient mechanism for price discovery. Many buyers find the auction shopping mechanism much interesting than regular storefront shopping.

Internet Banking
Today it is possible for you to perform the entire gamut of banking operations without visiting a physical bank branch. Interfacing of websites with bank accounts, and by extension credit cards, was the biggest driver of ecommerce.

Online Ticketing
Air tickets, movie tickets, train tickets, play tickets, tickets to sporting events, and just about any kind of tickets can be booked online. Online ticketing does away with the need to queue up at ticket counters.

Benefits of Ecommerce
The primary benefits of ecommerce revolve around the fact that it eliminates limitations of time and geographical distance. In the process, ecommerce usually streamlines operations and lowers costs.

Specialized Forms of Ecommerce
On some platforms, ecommerce has shown the promise of explosive growth. Two such examples are:

Mcommerce is short for "mobile commerce." The rapid penetration of mobile devices with Internet access has opened new avenues of ecommerce for retailers.

Fcommerce is short for "Facebook commerce." The immense popularity of Facebook provides a captive audience to transact business.**********

What is CSS?

CSS stands for Cascading Style Sheets
Styles define how to display HTML elements
Styles were added to HTML 4.0 to solve a problem
External Style Sheets can save a lot of work
External Style Sheets are stored in CSS files
CSS is a style language that defines layout of HTML documents. For example, CSS covers fonts, colours, margins, lines, height, width, background images, advanced positions and many other things. Just wait and see!

HTML can be (mis-)used to add layout to websites. But CSS offers more options and is more accurate and sophisticated. CSS is supported by all browsers today.

HTML is used to structure content. CSS is used for formatting structured content.

CSS was a revolution in the world of web design. The concrete benefits of CSS include:

control layout of many documents from one single style sheet;
more precise control of layout;
apply different layout to different media-types (screen, print, etc.);
numerous advanced and sophisticated techniques.
The basic CSS syntax

Let's say we want a nice red color as the background of a webpage:

Using HTML we could have done it like this:

<body bgcolor="#FF0000">

With CSS the same result can be achieved like this:

body {background-color: #FF0000;}

As you will note, the codes are more or less identical for HTML and CSS. The above example also shows you the fundamental CSS model:

Figure explaining selector, property and value

But where do you put the CSS code? This is exactly what we will go over now.
Applying CSS to an HTML document

There are three ways you can apply CSS to an HTML document. These methods are all outlined below. We recommend that you focus on the third method i.e. external.
Method 1: In-line (the attribute style)

One way to apply CSS to HTML is by using the HTML attribute style. Building on the above example with the red background color, it can be applied like this:

<body style="background-color: #FF0000;">
<p>This is a red page</p>

Method 2: Internal (the tag style)

Another way is to include the CSS codes using the HTML tag <style>. For example like this:

<style type="text/css">
body {background-color: #FF0000;}
<p>This is a red page</p>

Method 3: External (link to a style sheet)

The recommended method is to link to a so-called external style sheet. Throughout this tutorial we will use this method in all our examples.

An external style sheet is simply a text file with the extension .css. Like any other file, you can place the style sheet on your web server or hard disk.

For example, let's say that your style sheet is named style.css and is located in a folder named style. The situation can be illustrated like this:

The folder "style" containing the file "style.css"

The trick is to create a link from the HTML document (default.htm) to the style sheet (style.css). Such link can be created with one line of HTML code:

<link rel="stylesheet" type="text/css" href="style/style.css" />

Notice how the path to our style sheet is indicated using the attribute href.

The line of code must be inserted in the header section of the HTML code i.e. between the <head> and </head> tags. Like this:

<title>My document</title>
<link rel="stylesheet" type="text/css" href="style/style.css" />

This link tells the browser that it should use the layout from the CSS file when displaying the HTML file.
The really smart thing is that several HTML documents can be linked to the same style sheet. In other words, one CSS file can be used to control the layout of many HTML documents.

Figure showing how many HTML documents can link to the same style sheet

This technique can save you a lot of work. If you, for example, would like to change the background color of a website with 100 pages, a style sheet can save you from having to manually change all 100 HTML documents. Using CSS, the change can be made in a few seconds just by changing one code in the central style sheet.

Online processing, Real Time Processing, Batch processing

Online processing means users directly enter information online (usually, online, in this case, means online to a central processor, rather than its modern connotation of the Internet, but it could mean both!), it is validated and updated directly onto the master file. No new file is created in this case. Therefore, there is near immediate input process, and output. Imagine a cash dispenser transaction or booking a holiday at a travel agents or over the Internet. Compared with batch processing the number of transactions will be few.

In a real time processing, there is a continual input, process and output of data. Data has to be processed in a small stipulated time period (real time), otherwise it will create problems for the system.
For example: assembly line robots and radar system. 

In a batch processing group of transactions collected over a period of time is collected, entered, processed and then the batch results are produced. Batch processing requires separate programs for input, process and output. It is an efficient way of processing high volume of data.
For example: Payroll system, Examination system and billing system.

{***Batch processing refers to applications that are run in batches, often overnight due to limited system resources. For example, bank transaction processing is database intensive, so actually applying the transactions to all the accounts is done when the system is less busy. In batch processing all the data is stored and presented to the program(s) to handle them at once, in one or more large bundles or "batches."

Online processing is what you're doing right now. The application is waiting for you to tell it what to do, and it does it when you tell it to. In the bank example, accepting data for transactions and calculating the available balance would be done online. Online processing doesn't require being "on the line" of a network or modem connection, though nowadays it's quite common.

Real-time processing refers to applications that need to respond within a certain amount of time — usually on the order of seconds — to get the job done. Examples include rocket telemetry processing, many military applications, flight systems, and industrial automation and control systems. For example, if something goes wrong in a factory, a real-time system needs to be able to detect the situation and perform some action, such as notifying an operator or shutting down the problem area, within a few seconds.}*****

What is digital library?

A digital library is a library in which collections are stored in digital formats (as opposed to print, microform, or other media) and accessible by computers.[1] The digital content may be stored locally, or accessed remotely via computer networks. A digital library is a type of information retrieval system.
A digital library is a collection of documents in organized electronic form, available on the Internet or on CD-ROM (compact-disk read-only memory) disks. Depending on the specific library, a user may be able to access magazine articles, books, papers, images, sound files, and videos.

What is Data and Information?


    The word ‘Data’ is derived from the plural form of latin word ‘Datum’, which means ‘to give’.
    Data is a collection of raw facts.
    May or may not be meaningful.
    Input to any system may be treated as Data.
    Understanding is difficult.
    Data must be processed to understand.
    Data may not be in the order.
    Example: Statistics, numbers, characters, images.


    The word ‘Information’ is derived from latin word ‘Informare’, which means ‘to instruct’.
    Information is the outcome derived after processing the data.
    Information is always meaningful.
    Output after processing the system is Information.
    Understanding is easy.
    Information is already in understandable form, it may be processed further to make it more understandable.
    Information should be in the order.
    Example Reports, Knowledge.

What is Dynamic DNS?

Dynamic DNS or DDNS is a term used for the updating in real time of Internet Domain Name System (DNS) name servers to keep up to date the active DNS configuration of their configured hostnames, addresses and other information.

Dynamic Domain Name System, a method of keeping a domain name linked to a changing IP address as not all computers use static IP addresses. Typically, when a user connects to the Internet, the user's ISP assigns an unused IP address from a pool of IP addresses, and this address is used only for the duration of that specific connection. This method of dynamically assigning addresses extends the usable pool of available IP addresses. A dynamic DNS service provider uses a special program that runs on the user's computer, contacting the DNS service each time the IP address provided by the ISP changes and subsequently updating the DNS database to reflect the change in IP address. In this way, even though a domain name's IP address will change often, other users do not have to know the changed IP address in order to connect with the other computer.

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