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Types of Viruses

The Trojan virus gets its name from an incident that occurs in Homer's Iliad. Similar to how the Greeks in Homer's poem sent an army of men, hidden in a wooden horse, to the Trojans to get into the wall of the city. A Trojan horse appears to be nothing more than an interesting computer program or file, such as "saxophone.wav file" on the computer of user who's interested in collecting sound samples. The Trojan virus once on your computer, doesn't reproduce, but instead makes your computer susceptible to malicious intruders by allowing them to access and read your files. Making this type of virus extremely dangerous to your computer's security and your personal privacy. Therefore, you should avoid downloading programs or files from sites if you're not 100 percent positive of what the file or program does.
A Worm is a virus program that copies and multiplies itself by using computer networks and security flaws. Worms are more complex than Trojan viruses, and usually attack multi-user systems such as Unix environments and can spread over corporate networks via the circulation of emails. Once multiplied, the copied worms scan the network for further loopholes and flaws in the network. A classic example of a worm is the ILOVEYOU virus.
The best way you can protect yourself from worms is by updating your security patches. Operating systems and application vendors normally provide these patches. In addition, you should avoid opening email attachments from unknown senders.

Email viruses use email messages to spread. An email virus can automatically forward itself to thousands of people, depending on whose email address it attacks. To avoid receiving virus-laden emails, always check that your antivirus software is up-to-date and also stay clear of opening attachments, even from friends that you weren't expecting or don't know anything about.

Information technology 

What does the term Information Technology' really mean? Information technology is that technology by which the 'nformation is processed, communicated, exhibited and Retrieved in a fast, error-free and proper-way. Information technology is a technology in which both telecommunication computer technologies work together to provide formation.
Today's world is the world of information and telecommunication. Everyday new technology and inventions are being made in the area of information, processing and travelling.
 There is hardly any area which had not been affected by this. Due to all this, the word distance sounds ironical in present day context.
The whole world has become a small place today. Any information can be exchanged by people in few seconds and that, too, in proper and effective way without any loss of data while it is being processed. On the one hand, all these different ways of tele-communication and information exchage have highlighted the necessity for multipurpose development and growth of information technology and on the other, the easy access and use of it has boosted the network of information exchange.
All this has been possible through information technology like telephone, fax, telex, computers, internet, e-mail, photocopier, printer, scanner, cellular phones, pagers, videophone, digital camera, multimedia, etc.
These technologies are becoming a part and parcel of our lives and are transforming lifestyles and habits of people all over the world.
The use of computers has increased by leaps and bounds worldwide. Internet and multimedia have now become playthings for children. The internet has revolutionized every field of the world. The government has allowed private companies to provide internet services to people in order to boost up information technology.


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Types of communication network

 

Local Area Networks (LANs)

A computer communications network contained in a small area such as a commercial building is known as a local area network (LAN). The major benefit of a local area network is that it can help to reduce costs by allowing people and microcomputers to share expensive resources.

Metropolitan Area Networks (MANs)

The next larger network than LAN may be the Metropolitan Area Networks (MANs). MAN usually spans a geographical area that usually encompasses a city or county area. It interconnects various buildings or other facilities within this citywide area.

 wide area network(WAN)                           

A wide area network (WAN) is one that operates over a vast distance . Its nodes may span cities, states, or national boundaries. This network interconnects computers, LANS, BNs, MANS, and other data transmission facilities. Typically, WAN will employ communications circuits such as long- distance telephone wires, microwaves and satellites.

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What is Hardware?

Your PC (Personal Computer) is a system, consisting of many components. Some of those components, like Windows XP, and all your other programs, are software. The stuff you can actually see and touch, and would likely break if you threw it out a fifth-story window, is hardware.

Not everybody has exactly the same hardware. But those of you who have a desktop system, like the example shown in Figure 1, probably have most of the components shown in that same figure. Those of you with notebook computers probably have most of the same components. Only in your case the components are all integrated into a single book-sized portable unit.

The system unit is the actual computer; everything else is called a peripheral device. Your computer's system unit probably has at least one floppy disk drive, and one CD or DVD drive, into which you can insert floppy disks and CDs. There's another disk drive, called the hard disk inside the system unit, as shown in Figure 2. You can't remove that disk, or even see it. But it's there. And everything that's currently "in your computer" is actually stored on that hard disk. (We know this because there is no place else inside the computer where you can store information!).