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Computer power point presentation

  2. 2. INTERNET
  3. 3. INTROUCTION TO INTERNET The internet is a network consisting of thousands of small and large compute networks. In other words internet can be defined as a global network where million of computers are connected to each other. All computers connected on the net can exchange information by following certain rules called Protocols. Therefore a protocol is a set of rules which the computers use to communicate with one another across a network.
  4. 4. SERVICIES POVIDED BY INTERNET 1- World Wide Web (www) 2- E-Mail (Electronic mail) 3- News group 4- Chat 5- Bulleting Board Service 6- Video Conferencing 7- File Transfer Protocol (FTP) 8- E-Commerce 9- Telnet 10- Hyper Text Transfer Protocol (HTTP)
  5. 5. Components required to connect to Internet 1- A Computer System 2- A Modem 3- An Internet Service Provider (ISP) connection 4- An Internet browsing software.
  6. 6. Modem A modem is a computer device to connect to and communicate with other computes via a telephone line. Modem convents digital signals to analog symbols, which is known as Modulation and also converts the analog signals to digital signals, known as Demodulation. Hence the word Modem comes from Modulator and Demodulator. THERE ARE TWO TYPE OF MODEMS AVAILABLE :1- Internal Modem 2- External Modem.
  7. 7. INTERNET SERVICE PROVIDER (ISP) Internet Service Provides are companies that provide the Internet connection against charging some fee. ISPs use powerful computes called Savers with high storage capacity and memory, which is connected with other savers through satellites all over the world. The ISPs gives an account number an password to its user to gain access to the Internet. When we want to use the internet, you dial an get connected to an ISP. The ISP then handles al the communication between us and the Internet.
  8. 8. ISP IN INIDA SOME OF THE ISPS IN INIDA ARE:- • VSNL • MTML • Manta On-Line • Satyam On-Line
  9. 9. WEB BOWSER It is a software, which allows the user to access and browse information on the internet. Without a web browser internet cannot be accessed. Internet Explorer, Netscape Navigator, Opera an Mosaic are common examples of web browses.
  10. 10. WEBSITE A website is a collection of web pages which give information about an organization, a topic etc. A website can contain many Hypertext links which link to a piece of text or graphic that is like to some other text, graphic, page or file. TYPES OF WEBSITES :1- .com for Commercial Purposes like 2- .org for Organizations like 3- .edu for Educational Purposes like 4- .gov for Government like
  11. 11. UNIFORM RESOURCE LOCATOR (URL) URL provides an address to locate any site on the Internet. Every website has got a distinct URL. With the help of the URL, the web site is retrieved by the Web Browser. The URL helps the user to identify and locate any resource on the Internet.
  12. 12. Search engines Search Engine is a software that helps us to locate Web Pages on the Internet that contain information on the specified topics. We can search for any topic, images, news, video, meaning etc. using the search engines. SOME POPULAR SEARCH ENGINES ARE:1- http.// 2- http// 3- http// 4- http// 5- http// 6- http// etc.
  13. 13. Computer virus
  14. 14. COMPUTER VIRUS A computer virus is a program intentionally designed by a programmer for destroying system files and data of other computers. A virus program duplicates itself without any instruction from the user and damages the data on our disk by corrupting programs, or even formatting the entire hard disk. In other words we can say that virus simply replicates. Virus corrupts or damages the data without the knowledge of the user at a very great speed.
  15. 15. How does virus infect a computer system Computer virus spread with the great speed from one computer to another by means of infected disks, networks, programs downloaded from the Internet etc. a floppy disk can also infect a computer. Some virus programs are so well designed that they have a pre-set date or time on which they automatically. Virus can infect the display of a file or keyboard or any program files as word processor, database etc.
  16. 16. HOW DOES VIRUS SPREAD Virus can easily spread from one system to another by copying any infected application on starting the computer system. This is because the virus goes into the memory of the computer and starts infecting each application that gets executed by us. The virus programs get transferred into a computer through other virus infected programs, which we copy from floppies, CDs etc. examples of such viruses are Michealangelo, Monkey etc.
  17. 17. Different types of virus:Boot virus This type of virus infects the startup area of the hard disk o floppy disk. They attach themselves with the boot area and overwrite on the original instructions and take up control of the system. Booting means stating the computer and loading the operating system. EXAMPLES:Junkee, Ping Pong, Devil, Disk Killer etc.
  18. 18. PROGRAM VIRUS This type of virus infect application programs such as word processor, database etc. When the infected fie is executed, the virus gets activated and remains present in the main memory even when the execution of the file is over. When you execute another fie, the virus attaches itself to the new fie and thus another file gets infected. EXAMPLESEnigma, Trojan, Crazy, Yankee Doodle etc.
  19. 19. SYSTEM VIRUS These viruses attach themselves to the operating system and infect the input/output unit of the operating system. They always stay in the memory, damage parts of the operating system and then destroy themselves.
  20. 20. TROJAN HORSES AND WORMS Trojan horses programs are those programs that are useful to perform certain tasks. But at the same time they damage files or data in the system. This program destroys
  21. 21. Effects of virus 1- Viruses generally affect the software, files and folders of a computer. Hardware components are generally immune to viruses. 2- Fie with .exe extensions are soft targets to viruses. 3- Viruses can infect boot records thereby causing booting problems. 4- Other effects of viruses include corruption of data files, periodic hang- ups, slow system performance, loss of data etc. 5- Viruses can also alter the contents and the size of a file. 6- It can change the al the files names to a signal name. 7- It can erase programs or data. 8- It can overwrite entire directories. 9- It can create bad sectors in files and therefore destroy parts of the files
  22. 22. PRECAUTIONS WE SHOULD 1- Scan all floppies using antivirus software. 2- Write protect the floppies before coping data from other computer system. 3- Keep backup of all data and files. 4- Prepare an emergency boot disk. 5- Update your Antivirus program periodically. 6- Restrict the use of your computer system so that there is no unauthorized use.
  23. 23. We should not 1- Use floppies without scanning them for possible viruses. 2- Run an unknown program without using an antivirus to detect any viruses. 3- Allow everyone to use your computer system. 4- While using Internet do not download anything from the Internet without scanning for viruses.
  24. 24. ANTIVIRUS SOFTWaRE Antivirus is a software designed to detect and remove viruses from the computer system. Some types of virus are difficult to remove. Antivirus program gets activated whenever the computer system is booted up. IT DETECTES THE VIRUS AND REMOVES IT. ANTIVIRUS PROGRAM ARE OF TWO TYPES:1- SCANNERS 2:-ANTIDOTES
  25. 25. SCANNERS Scanners are programs that scan the disks to detect viruses. These programs scan the disk for any known virus. After scanning the disk and detecting the virus, they inform the user about the infected files. The user can then delete the infected file or get it cleaned by an Antidote.
  26. 26. ANTIDOTE Antidote are programmed to detect virus and clean the infected disk. Cleaning involves deleting the virus code from the infected file e.g. an Antidote detects virus in the boot area of a computer system. It will then delete the virus code and rewrite the programs back in their proper place. SOME POPULAR ANTIVIRUS SOFTWARES ARE:1- Norton Antivirus 2- Guardian 3- Smart Dog 4- McAfee etc.