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Mailam Engineering College (Approved by AICTE, New Delhi, Affiliated to Anna University, Chennai & Accredited by National Board of Accreditation (NBA), New Delhi) Mailam (Po), Villupuram (Dt). Pin: 604 304
DEPARTMENT OF COMPUTER APPLICATIONS
Web Programming – MC9235
UNIT II WORLD WIDE WEB
Overview – Web Security, Privacy, and site-blocking – Audio and Video on the web – Creating and Maintaining the Web – Web site creation concepts – Web Page Editors – Optimizing Web Graphics – Web Audio Files – Forms, Interactivity, and Database-Driven Web sites – File Transfer and downloading – FTP – Peer to Peer – Downloading and Installing software.
2– Marks Questions with Answers
1. What do you mean by World Wide Web? WWW is a distributed system of inter linked pages that include text, pictures, sound and other information. It enables easy access to the information available on the internet.
2. Write short notes on HTTP? Http is application protocol with the lightness and speed necessary for the distributed collaborative hypermedia information system.
3. What is FTP? The basic Internet File Transfer Protocol. FTP, which is based on TCP/IP, enables the fetching and storing of files between hosts on the Internet.
4. What is GUI? Graphical User Interface. Refers to the techniques involved in using graphics, along with a keyboard and a mouse, to provide an easy-to-use interface to some program.
5. What is URL? URL stands for Uniform Resource Locater. Three are two types of URL Absolute URL – This include complete path to the file location including all the names of directories and sub directories. Relative URL – These are like shorthand that tells the browser to go backward one or more directories to find the file.
6. Define SCML? The Source Code Markup Language (SCML) is a formatting language that can be used to create templates for source code that needs to be output by Flick.
7. What is Mailing List? A group of users with a shared interest, whose e-mail address are kept in an
Prepared By Ms. A.Subathra Devi, Asst. Prof. / MCA 2 electronic list that can be used to send e-mail to each member on the list.
8. What are the key elements in a protocol. ? Syntax - Includes data format and Signal levels Semantics – Includes control information for co-coordinating & Error handling Timing – Includes speed matching and sequencing
9. What is HTML? Hypertext Markup Language. This is a file format, based on SGML, for hypertext documents on the Internet. It is very simple and allows for the embedding of images, sounds, video streams, form fields and simple text formatting. References to other objects are embedded using URLs. HTML is a plain text file with commands
10. How do you change the color of background or text in HTML?
11. How do you use a picture as the background in HTML?
12. How do you add music to a web page?
13. Define Web Security. There are a lot of dangers in putting up a Web page. From invasions of privacy to actual hackers cracking your security. Learn how to secure your Web server and site as well as hacks and patches to keep yourself safe.
14. What are the necessities of using HTML forms?
Gathering user information Conducting Surveys Interactive services
15. What are the sequences of steps for each HTTP request from a client to the server?
Making the connection Making a request The response Closing the connection Define MIME.
MIME (Multipurpose Internet Mail Extensions) is an open standard for sending multipart, multimedia data through Internet email.
16. List the predefined MIME content types.
Prepared By Ms. A.Subathra Devi, Asst. Prof. / MCA 3
Text Multipart Message Image Audio Video Model Application
17. Define HTML. It is a simple page description language, which enables document creation for the web.
18. What is meant by loop back address? A zone that enables the server to direct traffic to itself. The host number is almost always 127.0.0.1.
19. What is web hosting? Web Hosting is a service that provides internet users with online computer systems for storing information, images, video, or any content accessible via the internet or web. For Internet users to view online information, the web hosting company places the website pages (html, php, etc files) on a web server which is stored inside a data center. Data centers are connected to the internet with extremely reliable high speed connections so that the world has access to the web files 24 hours a day, 7 days a week. Web users access the web pages through the website's IP address or the website's domain name.
20. What is a web host? A web host provider (or web host) is the company that host's and maintains the web server that stores the website's pages.
21. Does the web host own my site? No, the content that is within your site is yours and yours alone!
22. How much does web hosting cost? Web hosting costs vary dramatically depending on what type of website you plan on running, how many visitors the site receives, and any additional features you may require. For a simple site with html, cgi, and php web pages, the pricing can range from $15.00 per month to upward of $30.00 per month for a virtual web hosting account. If the website gets millions of visitors a day, you may require a dedicated server which can cost anywhere between $100.00 per month to $500.00 per month. This fee is to maintain a reliable high speed connection and enough bandwidth or data transfer per month for the website users to effective navigate through the website.
23. Can I host my website myself? Yes. It's preferable to have a high speed connection to the internet (DSL, Cable, or T1) and you can dedicate one computer to be a web server. Also, the internet provider may incur an extra charge for hosting.
However, this is the least efficient web hosting method since it puts heavy additional requirements on your home or office internet connection line and exposes you to security risks. It is important to note that the computer dedicated to being a web server must remain on 24 hours a day, 7 days a week for the website to be online all the time.
Prepared By Ms. A.Subathra Devi, Asst. Prof. / MCA 4
24. How do I transfer my website files from my local computer to the remote web hosting server? The most common method to upload files from a local computer to your web hosting server is by using an FTP, or File Transfer Protocol, client. An FTP client is a piece of software that allows a user to authenticate and establish a connection to the remote web hosting server to upload files for the website.
25. What is bandwidth or data transfer? Bandwidth or data transfer are terms referring to the amount of data that can be transferred in and out within a given period of time, usually monthly. When a visitor browses a website, he or she has to download the HTML, images, scripts and other files to view the web page. The amount of transfer the visitor uses counts towards your allocated monthly amount of data transfer. For example, if the visitor retrieves an image that is 2KB and one HTML page at 4KB, then the total data transfer for that session is approximately 6KB.
26. What is disk space or storage space? Disk space or storage space refers to the amount of space you are allowed to store in your web hosting account. When you upload website files, for example, HTML pages, images, graphics, scripts and so forth, it takes up space on the web server's hard drive(s). The size of the files you upload into your web hosting will respectively determine how much storage space you will use up.
27. How much disk space and bandwidth do I need for hosting my web site? There is no definite answer for this question since it is highly dependent on your current and future web hosting needs for the website in question. However, a small personal website with light traffic will require 50 - 100 MB of storage space (disk space) and 1 GB of monthly data transfer. JIC Design offers a Starter Web Hosting Plan suitable for this type of website. However, if the website offers videos or large resolution images, the Advanced Web Hosting Plan is a possibility.
28. How do I get my own domain name? It's important to realize that domain registration is separate from web hosting and these two services can be provided by two different companies. A domain name can be registered with any ICANN-approved domain registrar. JIC Design offers domain name registrations and includes a domain name free with specific web hosting plans.
29. How do I get started developing a Web site? Your Web site's purpose might be, for example, "to sell our line of products." A good purpose will be specific and represent a new activity that adds significant value to the Web. Then state specific, measurable objectives that the site should accomplish.
30. What is the most common mistake Web developers make? A lack of understanding of the audience for the Web site. Understanding your audience means knowing their needs and expectations. For example, a common error is when some sites that depend on an in-person visit neglect to identify the city and state in which the store or physical event is located. The developers forget that the Web site is global. Another common audience error is to assume that they know about the navigation cues on a site. Having symbols, links on certain words, and modes of representing the information based on clicking on links makes a site hard to navigate. The audience needs to
Prepared By Ms. A.Subathra Devi, Asst. Prof. / MCA 5 be able to find out the navigation scheme of a site. Ideally, the scheme should be self- evident, even to a brand new user.
31. What should I look for in a Web developer (or agency) I might hire? Ask the developers, "How can our needs be met with Web-based communication?" If the developers can articulate issues such as identifying your audience, meeting their needs, and taking advantage of the unique qualities of the Web for your Web's purpose, considers them. If the developers start blabbing on about technology--how cool Javascript (or frames, DHTML) is for example--don't hire them.
32. What is the difference between "Web development" and "Web design." Web development encompasses a whole set of processes, and one of those processes is Web design. Web design, unfortunately, has come to represent only page layout and graphics issues.
Web design as encompassing far more than that--including issues such as hypertext navigation, thematic issues that have to do with the Web's purpose, and organizational issues about the Web site's file organization. I hope people who call themselves "Web designers" understand this, but I think many do not.
33. What do you think are the best Web sites? Those that unabashedly focus on their purpose and have a strong sense of their audience. Yahoo.com's full coverage news area is absolutely fantastic--it accomplishes a specific purpose using the unique qualities of the Web; it has a clean layout and organization.
34. What is meant by cookies? A message given to a Web browser by a Web server. The browser stores the message in a text file. The message is then sent back to the server each time the browser requests a page from the server.
35. What are the advantages of using cookies? cookies do not require any server resources.
cookies are easy to implement.
you can configure cookies and expire when the browser ends.
36. What does XML stand for? In computer lingo XML stands for Extensible Markup Language. It is a textual data format and is used in interchanging data over the Internet. XML-based formats have become the default for most office-productivity tools, including Microsoft Office, OpenOffice.org, and Apple's iWork.
37. Write some advantages of XML. It is a platform independent language. It is as easy as HTML. XML is fully compatible with applications like JAVA, and it can be combined with any application which is capable of processing XML irrespective of the platform it is being used on.
Prepared By Ms. A.Subathra Devi, Asst. Prof. / MCA 6
XML is an extremely portable language to the extent that it can be used on large networks with multiple platforms like the internet, and it can be used on handhelds or palmtops or PDAs. XML is an extendable language, meaning that you can create your own tags, or use the tags which have already been created. It can be deployed on any network if it is amicable for usage with the application in use. If the application can work along with XML, then XML can work on any platform and has no boundaries. It is also vendor independent and system independent. While data is being exchanged using XML, there will be no loss of data even between systems that use totally different formats.
38. What do you need to become a hacker? Exstensive knowledge of computer and software security, lots of programming skills, and ingenuity.
39. What are the Advantages & Disadvantages of real time processing & batch processing? Advantages of Real Time processing The system is immediately updated. There will be (in most cases) no processing lag caused by the system.
Disadvantages Of Real Time Processing The system must always be online.
Advantages of batch processing It allows sharing of computer resources among many users. It shifts the time of job processing to when the computing resources are less busy. It avoids idling of computing resources with minute-by-minute human interaction and supervision.
Disadvantages It is difficult to provide the desired priority scheduling.
40. What is a Web directory? Basically web directory is a site where we can submit and fetch link on the basis of their categories. Is a strong medium of making backward links. Usually ppl got confused in search engine and in web directory both is different. There is no similarity between them. For Example-:http://www.google.com is a search engine and http://www.linksgallery.info is a web directory.
41. How do you get to blocked websites? There are specific websites that help bypass websites. However, some websites don't really work or the effect doesn't really take place. There are ways such as unlocking parental controls and editing it or going onto websites that allow to bypass areas where you're not allowed to go to. you could try either of them
42. How do you improve the visibility of a website? Apply SEO for the website so that it will create back links. Promote it the social media sites.
Prepared By Ms. A.Subathra Devi, Asst. Prof. / MCA 7
43. How do you create an Animated Image or Slideshow?
This can be done very easily in JavaScript using the set interval command and other piece of code in order to reproduce the HTML code therefore creating a slideshow. Dynamic Drive has a page on this with open source scripts you can use. I've added a link under related links.
44. What is difference between elements and attributes in XML? Elements are used to encapsulate pieces of data, and attributes are generally used to provide accompanying information about an element, rather than to encapsulate raw data itself.
45. How do you create an XML document? Open Microsoft excel, then do your work etc, then go to 'save as' than click save as xml document. You can use any basic text editor to create or with xml files, for example notepad can be used to create and edit xml files. You can also use a dedicated xml editor to achieve the same and to also carry out extra tasks like validation and binding.
46. What is Database Driven Web pages?
One of the most common types of dynamic web pages is the database driven type. This means that you have a web page that grabs information from a database and inserts that information into the web page each time it is loaded.
If the information stored in the database changes, the web page connected to the database will also change accordingly (and automatically,) without human intervention.
47. Define Web Browser
A web browser displays a web document and enables users to access web documents. When the user clicks a hyperlink, the browser initiates a message to a web server. This message requests the server to retrieve the requested information and send it back to the web browser through the telecommunications network.
48. What is meant by Peer-to-Peer? A peer-to-peer computer network is one in which each computer in the network can act as a client or server for the other computers in the network, allowing shared access to various resources such as files, peripherals, and sensors without the need for a central server.
49. How Does Internet P2P Work? The user must first download and execute a peer-to-peer networking program. After launching the program, the user enters the IP address of another computer belonging to the network. Once the computer finds another network member on-line, it will connect to that user's connection.
50. How does audio and video effects to website? [UQ Nov/Dec 2010]
Prepared By Ms. A.Subathra Devi, Asst. Prof. / MCA 8
There are many computer formats for sound, and theoretically any of them could be used in a web page. The three most popular formats (those most likely to work on your readers' machines) are WAVE, AU, and MIDI.
WAVE (Waveform Audio File Format, with the file extension .wav) was invented for Windows by Microsoft. AU (Audio File Format, file extension .au) was invented by NeXT and Sun. Both are now widely accepted on many platforms, and are common on web pages. WAVE and AU are like sound recordings... they reproduce recorded sounds (or computer generated sounds). They also tend to be big files for just a little sound. WAVE and AU files are good for a short sound effect such as a short greeting or perhaps a cow moo. There is also a recorded sound format called AIFF (Audio Interchange File Format), invented by Apple and SGI, which is widely supported, but is far less popular than AU and WAVE.
Video on the Web
Today, most videos are shown through a plug-in (like flash). However, different browsers may have different plug-ins. HTML defines a new element which specifies a standard way to embed a video/movie on a web page: the
51. what is database driven website, how they built? [UQ Nov/Dec 2010] A database-driven website is a website that uses a database to gather, display, or manipulate information. The web pages that are created when a database website design solution is used are actually called "dynamic web pages" as opposed to "static" web pages. The information contained in the database is usually kept up to date by using a website content management system. The content management system can be designed and tailored to your specific requirements.
Database driven sites can be built using several competing technologies, each with it’s own advantages. Some of those technologies/tools include:
PHP JSP ASP PERL Cold Fusion
52. What is a phishing web site? [UQ Nov/Dec 2011]
Phishing is attempting to acquire information such as usernames, passwords, and credit card details by masquerading as a trustworthy entity in an electronic communication. Communications purporting to be from popular social web sites, auction sites, online payment processors or IT administrators are commonly used to lure the unsuspecting public. Phishing emails may contain links to websites that are infected with malware. Phishing is typically carried out by e-mail spoofing or instant messaging, and it often directs users to enter details at a fake website whose look and feel are almost identical to the legitimate one
Prepared By Ms. A.Subathra Devi, Asst. Prof. / MCA 9
53. How to recognize phishing email messages, links, or phone calls
Phishing email messages, websites, and phone calls are designed to steal money. Cybercriminals can do this by installing malicious software on your computer or stealing personal information off of your computer.
Cybercriminals also use social engineering to convince you to install malicious software or hand over your personal information under false pretenses. They might email you, call you on the phone, or convince you to download something off of a website.
54. What does a phishing email message look like?
Here is an example of what a phishing scam in an email message might look like.
55. What is the typical database technologies used for running a database driven website? [UQ Nov/Dec 2011]
MS SQL Server or Oracle for high traffic database-driven web sites.
MySQL for low-cost database-access.
MS Access for low traffic web sites.
Part -B
1. Explain the World Wide Web Concepts in details.
The Hypertext Concept
The hypertext is a way of presenting information in such a way that the sequence of the information is left up to the reader.
This sequence is usually non-linear, however readers can follow a linear sequence.
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The hypertext works by means of hyperlink, which are highlighted or underlined words (or graphics) that one can click to bring another document into view.
Web Browser
A web browser displays a web document and enables users to access web documents.
When the user clicks a hyperlink, the browser initiates a message to a web server.
This message requests the server to retrieve the requested information and send it back to the web browser through the telecommunications network.
Web Server
This is a program that waits patiently for the browser to request a web page.
The server looks for the requested information, retrieves it and sends it to the browser or sends an error message if the file is not found.
Uniform Resource Locators (URL) and Transfer protocols
These are the web addresses.
The resource locator is an addressing system that precisely states where a resource is located.
It is divided into four parts: protocol; server/ domain name; path and the resource name. eg: http://www.cites.uiuc.edu/101/url101.html
The first portion of the URL (http) designates the protocol that is used to locate the file or resource on the Web.
A protocol is a standardized means of communication among machines across a network. Protocols allow data to be taken apart for faster transmission, transmitted, and then reassembled at the destination in the correct order.
Here, http represents the HyperText Transfer Protocol, which is used to transfer Web pages across the Internet to Web browsers such as Netscape Navigator, Internet Explorer, or Lynx.
The portion of the URL following the protocol (www.cites.uiuc.edu) designates the host name of the computer you are accessing. The designator www, found in many URLs, is an acronym for World Wide Web. While using www is conventional, it is not necessary. Some Web servers omit the need to type www.
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A URL may have any number of directories following it. In this example, 101 is a directory under the root directory of the host you are accessing. The file url101.html is located in the 101 directory.
2. What are Web Languages that are used to create web sites in details?
HTML (HyperText Markup Language)
It is the universal language understood by all WWW (World Wide Web) clients.
An HTML document (program) is ASCII text with embedded instructions (markups) which affect the way the text is displayed.
The basic model for HTML execution is to fetch a document by its name (e.g. URL), interpret the HTML and display the document, possibly fetching additional HTML documents in the process.
It can accept user input and/or cause additional HTML documents to be fetched by URL.
Providing safety, platform independence, and the ability to interact with a variety of formats, protocols, tools, and languages makes it a universal language.
Java and Java Script
Java is a language for sending applets over the web, so that the computer can execute them.
JavaScript is a language that allows HTML to embed small programs called scripts in web pages.
The main purpose of applets and scripts is to speed up web page interactivity.
VBScript and ActiveX Controls
VBscript resembles Microsoft’s Visual Basic and is used to add scripts to pages that are displayed by Internet explorer.
ActiveX controls, like Java, are used to embed executable programs into a web page.
XML
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. We must define our own tags XML is designed to be self-descriptive XML is a W3C Recommendation.
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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.
With XML we invent our Own Tags. The tags in the example below (like
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 (and the structure of HTML) are predefined. HTML documents can only use tags defined in the HTML standard (like
,
, etc.). XML allows the author to define his own tags and his own document structure.
Portals
A portal is a web site that wants to be the start page.
A portal site includes web guides, search engines, chat rooms, e-mail accounts and news services.
All portal services are free but some requires registering and choosing a password.
Corporations are replacing their internal homepages with portals.
Web directories and Search Engines
A web directory or link directory is a directory on the World Wide Web.
It specializes in linking to other web sites and categorizing those links.
A web directory is not a search engine, and does not display lists of web pages based on keywords, instead it lists web sites by category and subcategory. The categorization is usually based on the whole web site, rather than one page or a set of keywords, and sites are often limited to inclusion in only one or two categories.
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Web directories often allow site owners to directly submit their site for inclusion, and have editors review submissions for fitness.
A Web search engine is a search engine designed to search for information on the World Wide Web.
Information may consist of web pages, images and other types of files. Some search engines also mine data available in newsgroups, databases, or open directories.
Unlike Web directories, which are maintained by human editors, search engines operate algorithmically or are a mixture of algorithmic and human input.
A search engine operates, in the following order
1. Web crawling
2. Indexing
3. Searching
Web search engines work by storing information about many web pages, which they retrieve from the WWW itself. These pages are retrieved by a Web crawler— an automated Web browser which follows every link it sees.
When a user enters a query into a search engine (typically by using key words), the engine examines its index and provides a listing of best-matching web pages according to its criteria, usually with a short summary containing the document's title and sometimes parts of the text.
Most search engines support the use of the boolean operators AND, OR and NOT to further specify the search query. Some search engines provide an advanced feature called proximity search which allows users to define the distance between keywords.
Home Pages
The homepage or main page is the URL or local file that automatically loads when a web browser starts and when the browser's "home" button is pressed.
The term is also used to refer to the front page, webserver directory index, or main web page of a website of a group, company, organization, or individual.
In some countries, such as Germany, Japan, and South Korea, and formerly in the US, the term "homepage" commonly refers to a complete website (of a company or other organization) rather than to a single web page.
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Also, with more and more people knowing how to navigate the internet easily, the significance of choosing a homepage is almost non-existent.
Many software companies now automatically set their company's website as the user's homepage.
3. Discuss about Web Security, Privacy, and Site-Blocking
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 online 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 in 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 designed 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 built.
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 facilitate the following:
o Self-rating: Enable content providers to voluntarily label the content they create and distribute. o Third-party rating: Enable multiple, independent labeling services to associate additional labels with content created and distributed by others. Services may devise
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their own labeling systems, and the same content may receive different labels from different services. o 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.
4. Discuss how 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 the 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 downloading.
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 streaming 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.
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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
The video files are very large in size, meaning a video clip just a few seconds long could take ten minutes 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 downloaded 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 streaming video for their webcams.
5. What are the steps for Web site Creation?
Basic steps in creating a site
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.
Using the text editor 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.
Using browser, view the HTML files created. Check the contents and the links
Publish the web site by putting all of its files on a web server.
Using the browser, view the web pages as stored on the web server.
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Publicize the site, get feedback, get new ideas, and repeat the steps.
Planning the Site
The planning process involves answering these questions.
Who is the audience for the site?
What can you put on the site that will interest people?
How can we make it easy for people to navigate the site?
How the pages are stored on the site?
What are the tools needed to develop the site?
Issues to be aware of when planning the web site:
Text size
Colors
Writing for an international audience
Privacy
Maintenance
Accessibility
Tools needed to develop the site
Text
Pictures
Animated graphics
Audio files
Video files
Animation files
Forma and database information
Text editor
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Drawing programs
Clip art gallery
Sound or video equipment
6. Briefly discuss about Optimizing web graphics and its file formats.
Graphics File formats
Vector images consist if lines and various shapes outlined and filled with colors or shadings.
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:
Paint and photo programs – Enables to read different image files and customize them for web use. Eg: Adobe Photoshop and Macromedia fireworks
Illustration programs – focus on creating images, principally vector graphics and have features for optimizing the bitmap files. Eg: Adobe Illustrator and CorelDraw.
Graphics Utilities - small programs with simple features that focus on converting images from one format to another.
Graphics program that are widely available:
Microsoft Paint
Adobe PhotoShop
Adobe ImageReady
Macromedia Fireworks
Paint Shop Pro
Lview pro
Optimizing Images
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.
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Digitized images are normally at a much higher quality (resolution / dots per inch) than a monitor can display.
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).
The Second best method (optional) is to 'crop' off any 'dead' area. For example, center the subject in the picture by cropping the borders.
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.
Minimize the image dimensions by using the smallest practical image height and width.
Minimizing or avoiding certail types of Image content.
Minimizing and flattening colors.
7. What is FTP, and how do I use it to transfer files? [UQ Nov/Dec 2010&2011] 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 FTP runs exclusively over TCP. FTP servers by default listen on port 21 for incoming connections from FTP clients. A connection 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 for 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 client 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 host IP, followed by the chosen data port. For example, a
Prepared By Ms. A.Subathra Devi, Asst. Prof. / MCA 21 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 this 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 explained 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 which 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 September 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 successfully transferred, the control session can be disconnected by the firewall, causing an error to be generated.
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 completion, 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:
To promote sharing of files (computer programs and/or data).
To encourage indirect or implicit use of remote computers.
To shield a user from variations in file storage systems among different hosts.
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:
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ASCII mode
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 format (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 between 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 carriage 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 transferring from the system using ASCII to the mainframe, ASCII characters will be translated to their EBCDIC equivalents.
By default, most FTP clients use ASCII mode. Some clients try to determine the required transfer-mode by inspecting the file's name or contents, 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:
EBCDIC mode - this transfers bytes, except they are encoded in EBCDIC rather than ASCII. Thus, for example, the ASCII mode server
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 lack 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)://
List of FTP commands Commands 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.
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ALLO - Allocate sufficient disk space to receive a file.
APPE - Append.
CDUP - Change 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 feature 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.
LIST - Returns information of a file or directory if specified, else information 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 multiple 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.
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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 - Remove 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 - Store file uniquely.
STRU - Set file transfer structure.
SYST - Return system type.
TYPE - Sets the transfer mode
UMNT - Unmount file structure.
USER - Authentication username
8. Discuss the concepts of Peer-to-peer
Prepared By Ms. A.Subathra Devi, Asst. Prof. / MCA 25
Peer-to-peer Architecture
Often referred to simply as peer-to-peer, or abbreviated 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 networks 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. 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 are 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 Computing:
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 to 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 real-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 users collaborating and searching other user's computers for information and files.
How Peer-to-peer File-sharing Clients Work:
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Once you have downloaded and installed a P2P client, if you are connected to the Internet you can launch the utility and you are then logged into a central indexing 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 computers 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 network 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 watch 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 even 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 physically 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.
9. Briefly explain the types of authentication? 1. Passwords
Passwords are the easiest and most common authentication process that are used, not only on desktop computers but also at the network level. However certain rules should be followed when setting a password for your computer or Network. Do not use easily predictable words for your passwords; they don't even require a hacker to access the system through your account. Use passwords that are unpredictable. Set long passwords and use numbers and special characters when setting your password. Remember your passwords; don't write it down anywhere. Hackers use various tools to know your
Prepared By Ms. A.Subathra Devi, Asst. Prof. / MCA 27
passwords, but a long password with a number of special characters, indeed gives them a lot of trouble.
2. Digital Certificates
Using a certain algorithm, computer administrator combine your personal details with other user credentials to generate a public key. This public key or digital certificate is used for the authentication purpose in the network.
3. Smart Cards
Smart Cards are among the very few hardware authentication processes in which a simple card with an embedded circuitry is used for accessing the network. Each valid card for a particular network, when inserted into the circuitry it has been made for, gives an output which decides whether you will be allowed to enter into the network or not. The programming logic inserted into each card is different and it is one of the safest methods of authentication.
4. Fingerprint detection
Almost available in all laptops that are manufactured today; fingerprint detection is another safe method of computer security authentication. Everyone knows that even the iris pattern of two people may even match, but fingerprints can never match.
5. Face recognition systems
Face recognition system, may amuse you, but of late many people working in the field of security have questioned its user friendly nature and the security it can provide. A simple dimension calculation of the face is done by the computer and the logic used in doing so, has been often found to be prone to errors.
6. Biometrics
Biometrics is often considered as a far more secure way of authentication than passwords or digital certificates. It is even safer than smart cards, which may be misplaced. The physical and behavioral traits of a person are taken into consideration in this type of authentication.
7. Captcha Keys
This is the process of authentication that is used to verify whether a human or a computer bot has logged into the system. Captcha keys are randomly generated alphabets and numericals presented in such a form, that only a human can recognize.
The above listed methods are just a few of the widely used authentication methods. In fact, the measures that we take for safeguarding our computer or network are more important than the method itself. Many of us have a habit of naming our networks after the protagonist from our favorite movie. This should be avoided and networks should have sensible names that cannot be easily determined. If you are a network administrator in charge of a closed secure network, then it is always desirable to set your network visibility status to the invisible mode.
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10. Write a short note on web page editors. [UQ Nov/Dec 2010]
This is a program that you use to create Web pages. It can be something as simple as the text editor that came with your computer or it can be something that creates the page right in front of you as you point and click away. If you like to design your pages using HTML then you will probably us a text editor of some sort. They come with a wide variety of options including templates, spell checkers, color coding and much more.
Examples:
Web Authoring / HTML Editors / XHTML Editors
Arachnophilia, by P. Lutus
HTML editor, programming editor for Windows. Includes search/replace features, spell checker, will tidy up your markup, has customization available, macros, has built-in FTP service, more. Supports ASP and PHP, too. Loyal following of devoted users. Free. For Windows.[Software by P. Lutus.]
BBEdit, by Bare Bones Software
Top-ranking HTML editor for Macs. Although I haven't personally used it, those using HomeSite (for PCs, below) and BBEdit compare them as similar. Syntax coloring and function navigation support for HTML, JavaScript, Perl, PHP, Ruby, SQL, XHTML, XML, and YAML. Syntax coloring, function navigation, and markup support for CSS. Local preview server for preview of code generated by PHP, Perl, includes, and similar. Built-in support for Dreamweaver. More. Try their Lite version, or download a free trial from their Web site. Prices 01-2008: around $125 full; $30-$40 upgrade; $49 educational. For Mac.[Software by Bare Bones Software.]
CoffeeCup HTML Editor, by CoffeeCup Software, Inc.
HTML editor with WYSIWYG. Includes FTP, drag-and-drop capabilities, XHTML conversion tool, support for PHP and other programming languages, built in CSS editor, spell check, built in sitemapping tool, CoffeeCup Image Mapper, much more.
Dreamweaver, by Adobe (formerly by Macromedia)
Another top-ranking HTML program. Integrates with Macromedia HomeSite, Adobe Fireworks, and other software programs. Free trial download. Excellent HTML editor, XHTML editor, accessible to those not knowing HTML, and gaining in popularity among Web site developers, companies, large corporations, and individuals for Web site building, maintenance and especially for managing large sites. Dreamweaver also supports W3C Recommendations and does pretty well with its WYSIWYG features - far superior to FrontPage. Prices 01-2008: around $399 full; $199 upgrade, educational. For Windows and Mac.
Expression Web Designer, by Microsoft
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Expression Web Designer replaces FrontPage and is a new product by Microsoft, part of the Expression family that includes Expression Web Designer, Expression Graphic Designer, and Expression Interactive Designer. Much better CSS support, better support for Web standards than its predecessor.
FrontPage, by Microsoft
Editor Note May 2007: FrontPage was replaced with Expression Web Designer as of this note, you'll still find support information at Microsoft's site.
GoLive, by Adobe
A direct competitor with Dreamweaver, and a powerful Web authoring tool with WYSIWYG capabilities. Also allows easy converting of Adobe InDesign® layouts into Web pages. Editor note May 2007: GoLive development will continue as a standalone software product (announced by Adobe November 2006), although Adobe is also encouraging users to switch to Dreamweaver. For Windows and Mac.[Software by Adobe.]
HomeSite, by Macromedia
Top-ranking HTML software for PCs, among the top favorites used by Web site developers. Supports PHP, integrates well with Dreamweaver, Cold Fusion and other programs. Accessible for new users, too. Excellent HTML editor. Free trial download. Editor note February 2006: Adobe and Macromedia merged. HomeSite development has been stagnant for some time, even though devoted HomeSite fans continue to hope for updates. Watch their site for the latest. Prices 01-2008: around $99 full; $29 upgrade. For Windows.
HTML-Kit Tools (Formerly HTML-Kit), by Chami
Popular Web developer tool for HTML and more. Includes many plugins, such as CSS, HTML Tidy, W3C HTML and CSS references, XHTML, JavaScript, ASP, ColdFusion, Perl, PHP, SSI, SQL, and more. Prices 01-2008: around $65 full; free upgrade for registered HTML-Kit 1.0 users. For Windows.[Software by Chami.]
NoteTab, by Fookes Software
Top-rated text and HTML editor shareware. Awards from PCMagazine and others. Simple to use and helpful with HTML, CSS, PHP, CGI scripts, more. Search/replace, drag and drop files, convert text to HTML, strip tags, more. Prices 01-2008: around $29.95 Pro; $19.95 Standard; Free Lite version. For Windows.[Software by Fookes Software.]
TextPad, by Helios Software Solutions
Powerful, general purpose editor for plain text files. Spell checker, edit multiple files, unlimited undo/redo, sorting, powerful search/replace, bookmarks, file manager, comparison utility, more. Add utilities, clip libraries, dictionaries, macros, syntax definitions, and more for greater functionality. Around US $27, free trial download. Prices 01-2008: around $33.00 full; free upgrade to TextPad 5 from Textpad 4. For Windows.[Software by Helios Software Solutions.]
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TopStyle CSS, HTML, XHTML Editor, by NewsGator Technologies
Top-rated editor for PCs (5 stars with ZDNet, PCMagazine, CNet, more). Integrates seamlessly with Macromedia HomeSite, Macromedia Dreamweaver, CSE HTML Validator, NoteTab, and others. The Lite version is already included in HomeSite (and possibly other programs, too). Popular program with Web site developers. Highly recommended by WebsiteTips.com and used for this Web site. Download trial or purchase online. Prices 01- 2008: around $79.95 full; free upgrade within version 3; $24.95 upgrade prior to version 3; Free Lite Version. For Windows.
11. Discuss the vulnerability of internet technology for security threats. [UQ Nov/Dec 2011]
Wireless networking presents many advantages Productivity improves because of increased accessibility to information resources. Network configuration and reconfiguration is easier, faster, and less expensive. However, wireless technology also creates new threats and alters the existing information security risk profile. For example, because communications takes place "through the air" using radio frequencies, the risk of interception is greater than with wired networks. If the message is not encrypted, or encrypted with a weak algorithm, the attacker can read it, thereby compromising confidentiality. Although wireless networking alters the risks associated with various threats to security, the overall security objectives remain the same as with wired networks: preserving confidentiality, ensuring integrity, and maintaining availability of the information and information systems. The objective of this paper is to assist managers in making such decisions by providing them with a basic understanding of the nature of the various threats associated with wireless networking and available countermeasures.
The popularity of wireless Networks is a testament primarily to their convenience, cost efficiency, and ease of integration with other networks and network components. The majority of computers sold to consumers today come pre-equipped with all necessary wireless.
Networks technology. The benefits of wireless Networks include: Convenience, Mobility, Productivity, Deployment, Expandability and Cost.
Wireless Network technology, while replete with the conveniences and advantages described above has its share of downfalls. For a given networking situation, wireless Networks may not be desirable for a number of reasons. Most of these have to do with the inherent limitations of the technology. The disadvantages of using a wireless network are Security, Range, Reliability, and Speed.
Wireless Networks present a host of issues for network managers. Unauthorized access points, broadcasted SSIDs, unknown stations, and spoofed MAC addresses are just a few of the problems addressed in WLAN troubleshooting. Most network analysis vendors, such as Network Instruments, Network General, and Fluke, offer WLAN troubleshooting tools or functionalities as part of their product line.
Wireless Vulnerabilities, Threats and Countermeasures
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The wireless networks consist of four basic components: The transmission of data using radio frequencies; Access points that provide a connection to the organizational network and/or the Client devices (laptops, PDAs, etc.); and Users. Each of these components provides an avenue for attack that can result in the compromise of one or more of the three fundamental security objectives of confidentiality, integrity, and availability.
12. Describe the use of forms in web documents and the technology by which the forms handled at the server. [UQ Nov/Dec 2011]
Introduction to Web Forms Pages Web Forms pages to create programmable Web pages that serve as the user interface for your Web application. A Web Forms page presents information to the user in any browser or client device and implements application logic using server-side code. Web Forms page output may contain almost any HTTP-capable language, including HTML, XML, WML, and ECMAScript (JScript, JavaScript).
Web Forms pages are:
Based on Microsoft ASP.NET technology in which code that runs on the server dynamically generates Web page output to the browser or client device. For details about ASP.NET.
Compatible with any browser or mobile device. A Web Forms page automatically renders the correct browser-compliant HTML for features such as styles, layout, and so on. Alternatively, you can design your Web Forms pages to run on a specific browser such as Microsoft Internet Explorer 5 and take advantage of the features of a rich browser client.
Compatible with any language supported by the .NET common language runtime, including Microsoft Visual Basic, Microsoft Visual C#, and Microsoft JScript .NET.
Built on the Microsoft .NET Framework. This provides all the benefits of the framework, including a managed environment, type safety, and inheritance.
Supported in Visual Studio with powerful rapid application development (RAD) tools for designing and programming your forms.
Components of Web Forms In Web Forms pages, the user interface programming is divided into two distinct pieces: the visual component and the logic. If you have worked with tools like Visual Basic and Visual C++ in the past, you will recognize this division between the visible portion of a form and the code behind the form that interacts with it.
The visual element is referred to as the Web Forms page. The page consists of a file containing static HTML, or ASP.NET server controls, or both simultaneously.
The Web Forms page works as a container for the static text and controls you want to display. Using the Visual Studio Web Forms Designer plus ASP.NET server controls, you can design the form as you would in any Visual Studio application.
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Web Forms File Structure
The code-behind class files for all Web Forms pages in a project are compiled into the project dynamic-link library (.dll) file. The .aspx page file is also compiled, but somewhat differently. The first time a user browses to the .aspx page, ASP.NET automatically generates a .NET class file that represents the page, and compiles it to a second .dll file. The generated class for the .aspx page inherits from the code-behind class that was compiled into the project .dll file. When a user requests the Web page URL, the .dll files run on the server and dynamically produce the HTML output for your page. For more information.
What Web Forms Pages Help You Accomplish Web application programming presents challenges that do not typically arise when programming traditional client-based applications. Among the challenges are:
Implementing a rich Web user interface. A user interface with a complex layout, a large amount of dynamic content, and full-featured user-interactive objects can be difficult and tedious to design and implement using basic HTML facilities. It is particularly difficult to create a rich user interface for applications likely to run on many different browser and client device platforms.
Separation of client and server. In a Web application, the client (browser) and server are different programs often running on different computers (and even on different operating systems). Consequently, the two halves of the application share very little information; they can communicate, but typically exchange only small chunks of simple information.
Stateless execution. When a Web server receives a request for a page, it finds the page, processes it, sends it to the browser, and then, effectively, discards all page information. If the user requests the same page again, the server repeats the entire sequence, reprocessing the page from scratch. Put another way, a server has no memory of pages that it has processed. Therefore, if an application needs to maintain information about a page, this becomes a problem that has to be solved in application code.
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Unknown client capabilities. In many cases, Web applications are accessible to many users using different browsers. Browsers have different capabilities, making it difficult to create an application that will run equally well on all of them.
Complications with data access. Reading from and writing to a data source in a traditional Web applications can be complicated and resource-intensive.
Complications with scalability. In many cases Web applications designed with existing methods fail to meet scalability goals due to the lack of compatibility between the various components of the application. This is often the single failure point for applications under a heavy growth cycle.
13. Create an online shopping webpage using HTML forms and other technologies necessary for that. [UQ Nov/Dec 2010] h.html
title.html
frame.html
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![](”pictures/TF1572_gift_m.jpg")
// Ref. Lab Program
ANNA UNIVERSITY
PART – A
1. How does audio and video effects to website? [Ref. No.: 50] 2. What is database driven website, how they built? [Ref. No.: 51] 3. What is a phishing web site? [Ref. No.: 52] 4. What is the typical database technologies used for running a database driven website? [Ref. No.: 55]
PART – B
1. What is FTP, and how do I use it to transfer files? [Ref. No.: 7] 2. Write a short note on web page editors. [Ref. No.: 10]
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3. Discuss the vulnerability of internet technology for security threats. [Ref. No.: 11] 4. Describe the use of forms in web documents and the technology by which the forms handled at the server. [Ref. No.: 12] 5. Create an online shopping webpage using HTML forms and other technologies necessary for that. [Ref. No.: 13]
Prepared By Ms. A.Subathra Devi, Asst. Prof. / MCA