Desktop publishingUsing a personal computer or workstation to produce high-quality printed documents. A desktop publishing system allows you to use different typefaces, specify various margins and justifications, and embed illustrations and graphs directly into the text.

Desktop publishing software can generate layouts and produce typographic quality text and images comparable to traditional typography and printing. This technology allows individuals, businesses, and other organizations to self-publish a wide range of printed matter. Desktop publishing is also the main reference for digital typography.

DTP software is generally interactive and WYSIWYG in design.

What is computer virus?computer virus infects your programs and files of your PC. Yes, it is an executable program which affects the normal operation of the computer by damaging the contents of the hard disk. It could cause frequent computer crashes, delete files, weakens computer memory and even reformatting the hard drive.

How does computer viruses reach you?Different types of computer viruses would reach you through the normal web activities like,

1. Opening email attachments from fake accounts.

2. Clicking inappropriate internet advertisements without understanding fully.

3. Installing/downloading the free games, tool-bars or system utilities.

4. Visiting an infected webpage

5. Setting up of software without license agreements and so on.

Not only with web activities, if you are not running the latest updates of your operating system and not using the good antivirus software, computer viruses would reach you easily.

Types of computer virusesMany types of viruses are present and some popular viruses types are

1. Macro Virus

Macro virus is a type of email virus which mainly targets to infect the programs that contain Macros like Microsoft office files. These are mini programs which have the power to infect the template and document of that file.

2. Memory resident virus

Memory resident virus automatically fixes themselves in the computer memory and if the operating system started to run, it gets activated. It hideout in the computer memory and allocates space to execute its own code. It can easily corrupt the files which are recently used.

3. Multipartite Virus

Multipartite virus spreads in multiple ways and infects the programming files. They used to hide in the memory like Memory resident virus and do infect the hard disk.

4. Polymorphic Virus

Polymorphic virus are the powerful virus which might guards itself with encryption algorithm and has the tendency to change automatically when certain conditions are meet. Because of having encrypting capability, it is tough to find it by even with an antivirus program.

5. FAT virus

FAT virus spoils the file allocation system section (Information where the location of files and the details of the available spaces are stored) and might cause crucial damage to it. It would result in defeating the individual files or complete directories.

E-MailE-mail or electronic mail is a service for sending or receiving messages electronically through acomputer network. The electronic mail uses various technologies that support electronic transmission oftext, data and graphics.Some of the features of E-mail are1. it is much faster than the normal mail. Messages can be sent within a matter of seconds to anypart in the world.2. it can be sent to many people at the same time3. E-mail is cheaper than a phone call and an ordinary mail4. it can access information and file libraries on request5. E-mail user can have a mail box which is accessed through a computer terminal6. an E-mail message consists of two partsa) a header specifying the address of the sender and the address of the receiverb) the text of the message

7. The mailing system allows selecting messages for reading, displaying, saving, deleting,forwarding and replying.8. Mailing list can be created to send the same message to a group of people

E-Mail Address: An E-Mail address consists of three parts1. The person‘s Login name2. @ sign3. Domain nameA domain represents organization, network, and country nameEx: Statisitcs@hotmial.com in this Statistics is the user name and his account is in the domain

hotmail.com. Both the names are separated by the @symbol.Search Engines :Search engines are utilities used to search for information on the web. A user interface is providedwhere you can enter the word or phrase you are searching for. The search engine looks for the keywordswe have entered and returns the results of the search, providing links to relevant Web sites for us tochoose from. Some commonly used search engines are MSN, Alta Vista, Google, Yahoo! search andInfoseek etc.

INTERNETThe internet is a global connection of computers. These computers are connected via a hugenetwork of telecommunication links. The internet allows you to access to a whole resource of data andinformation stored at different sites (called hosts) and locations around the world. The communicationlinks which inter connect each host computer use a common method of transmission known as TCP/IP,which stands for Transmission Control Protocol / Internet Protocol.Internet connection helps us to:1. Read information on a wide range of topics2. Send or receive E-mail3. Down load useful programs such as virus detectors, file compression, decompression utility etc.,4. Share your opinions and your knowledge on a variety of topics through various new groups.5. Chat with other people any where in the world6. View interesting video‘s listen to music or wander through a 3-D world.Requirements for connecting to the Internet:a) Modem: A modem is a peripheral device that allows a computer to connect andcommunicate with other computers. Modem stands for Modulator Demodulator.b) Web Browser: A browser is a software program that is necessary in order to view webpages on the web. Ex: Internet Explorer, Netscape Navigator, Mozilla Firefox,Microsoft outlook express etc.c) Telephone line: A telephone line is required to transfer data from one computer toanother. The computer is connected to a modem, which, in turn, connected to a telephoneline.

d) Subscription with Internet service provider (ISP): ISP‘s are companies that provideaccess to the internet. We need subscription with any ISP to get an Internet connection.Some of the ISPs in India are VSNL, MTNL, Sify, Specrta Net etc.

World Wide Web (WWW):It refers to the collection of information accessible on the internet. The web is similar to a library. Itconsists of millions & millions of pages of text, pictures, sounds and animation on various topics. Thesepages, called web pages are stored on different computers that are connected to the internet. The webpages have links between them i.e when we click a certain word or picture in a page, it will take us toanother page. These words or pictures that help to move from one page to another are called hyperlinks.A collection of related web pages is known as a web site. A web site can be accessed by means of aunique name assigned to it.Internet was initially designed for the transmission of text basing on the protocols mentioned.In order to transmit a graphically designed web page complete with pictures, embedded sound andanimation a special language was designed which is referred to as Hyper Text Mark up Language(HTML). HTML uses special text codes to define the various elements of a web page.The WWW support a protocol called Hyper Text Transfer Protocol (HTTP). All internetservers cannot support HTTP and so the web can be regarded as a subset of the larger internet.HTTP provides a method of transmitting a professionally laid out page over the text based internet.Uniform Resource Locator: (URL): Each web site has a unique address commonly referred to as aURL. A URL specifies the exact location of the web page on the internet.

A typical web address or URL looks as http://www.microsoft.com/catalog/navigation.aspExplanation of the example URL:

URL Element Explanationhttp Identifies protocol necessary to retrieve the file.WWW Indicates that the site is on the world wide webMicrosoft Indicates the name of the web site.com Indicates the domain type of the web site/catalog/navigation.asp Specifies the path of the file stored on the web server‘s hard disk