Bioinformatics - Internet
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The document discusses the Internet and how it connects computers worldwide. It describes the Internet as a network of networks that connects millions of computers. It discusses how individuals and organizations can access the Internet through schools, businesses, Internet service providers or by connecting their personal computers. It also summarizes the basic functions and uses of the Internet, how files and information are transmitted over the Internet using protocols like TCP/IP, and how domain names and IP addresses work to locate computers and resources on the World Wide Web.
Bioinformatics - Internet
- 1. INTERNET DR. K. RAMESHKUMAR ASSISTANT PROFESSOR PG & RESEARCH DEPT. OF ZOOLOGY Vivekananda College Tiruvedakam- West MADURAI - Dt
- 2. Internet The Internet is a worldwide collection of computer networks It is the largest network in the world that connects thousands of individual networks all over the world. The popular term for the Internet is the “information highway”.
- 3. Rather than moving through geographical space, it moves your ideas and information through cyberspace – the space of electronic movement of ideas and information. The Internet is a network of networks that connects users in every country in the world. There are currently over one billion Internet users worldwide.
- 5. The uses of the Internet Send e-mail messages. Send (upload) or receive (down load) files between computers. Participate in discussion groups, such as mailing lists and newsgroups. Surfing the web.
- 6. How to access the Internet? Many schools and businesses have direct access to the Internet using special high-speed communication lines and equipment. Students and employees can access through the organization’s local area networks (LAN) or through their own personal computers. Another way to access the Internet is through Internet Service Provider (ISP).
- 7. How to access the Internet? To access the Internet, an existing network need to pay a small registration fee and agree to certain standards based on the TCP/IP (Transmission Control Protocol/Internet Protocol) reference model. Each organization pays for its own networks and its own telephone bills, but those costs usually exist independent of the internet. The regional Internet companies route and forward all traffic and the cost is still only that of a local telephone call.
- 8. Network Most people work in a network environment A network is a collection of computers connected together with special hardware and software to manage it. LAN – Local Area Network (small area) WAN – Wide Area Network (long distances)
- 9. From LAN to WAN (a) Home Network (b) Local Area Network
- 10. From LAN to WAN (continued) (c) Wide Area Network
- 11. Internet Service Provider (ISP) A commercial organization with permanent connection to the Internet that sells temporary connections to subscribers. Examples: Prodigy, America Online, Microsoft network, AT&T Networks.
- 12. The Internet and How We Connect to It Using an ISP
- 13. The Internet and How We Connect to It Using an ISP
- 14. The Internet and How We Connect to It Using an ISP ISPs provide a variety of ways to connect to the Internet, depending on location and desired connection speed. The choice of Internet access technologies depends on availability, cost, access device used, media used and the speed of the connection.
- 16. The Internet and How We Connect to It Using an ISP The contract with the ISP determines the type and level of services that are available.
- 17. How Information is Sent When Using an ISP The most important protocol of the Internet is the Internet Protocol (IP).
- 18. The World Wide Web (www) The Web presents information through multimedia formats: graphics, sound, animation, and video. The Web uses several tools to provide a visual layout: Hypertext links Browser software Code structure The Web resembles an electronic library – each location or site is like a book. These books are created using Hypertext Markup Language (HTML). These materials, along with interactive objects such as Java, JavaScript, and VBScript adds functionality to web pages.
- 19. Structure of the Web Web is a collection of files that reside on computers, called Web servers, that are located all over the world and are connected to each other through the Internet. When you use your Internet connection to become part of the Web, your computer becomes a Web client in a worldwide client/server network. A Web browser is the software that you run on your computer to make it work as a web client.
- 20. Client vs. Server When you connect to Internet to become part of the web, your computer becomes a Web client in a worldwide client/server network. Web browser is the software that you run on your computer to make it work as a Web client.
- 21. Hypertext Markup Language (HTML) The public files on the web servers are ordinary text files, much like the files used by word-processing software. To allow Web browser software to read them, the text must be formatted according to a generally accepted standard. The standard used on the web is Hypertext markup language (HTML).
- 22. Hypertext Markup Language (HTML) HTML uses codes, or tags, to tell the Web browser software how to display the text contained in the document. For example, a Web browser reading the following line of text: <B> A Review of the Book<I>Wind Instruments of the 18th Century</I></B> recognizes the <B> and </B> tags as instructions to display the entire line of text in bold and the <I> and </I> tags as instructions to display the text enclosed by those tags in italics.
- 23. Connecting to the Internet Elements required to connect to the Internet: Computer, WebTV, mobile phone, or Personal Digital Assistant (PDA) Dial-up modem, digital subscriber line (DSL) modem, or cable modem Operating System: Windows 95/98/Me, Windows NT/2000/XP, Linux/UNIX, Macintosh Telecommunications/Client Software: Web browser, e-mail or news client programs Internet Connection (telephone line or cable connection): dial-up or direct connection to an Internet Service Provider (ISP) or Value-Added Network (VAN) such as America Online (AOL) or Microsoft Network (MSN) Internet Addresses: Web addresses (e.g., www.msn.com), e-mail addresses (e.g., student@class.com), server addresses (e.g., ss1.ProSoftTraining)
- 24. Connecting to the Internet • At Work or School – Via a Local Area Network • At Home – Traditional Modem (56Kbps) – Cable Modem • Uses TV cable • Requires network card – DSL Modem • Voice and data on the same line • Requires network card
- 25. Connection Types Dial-Up Connection Use a modem to access the Internet on a per-use basis. The user accesses the ISP via phone line and when finished, disconnects from the ISP. The speed of access is determined by the speed of your modem. To gain faster access, you can install an Integrated Services Digital Network (ISDN) line, which is a digital phone line. Direct Connection Provide continuous access to the Internet Convenient and fast and capable of handling high bandwidth
- 26. Domain Name System (DNS) To access a website, you must enter the address of the web server in your browser. The IP address (the dotted quad) is one way to identify the server; however, most users prefer to use domain names because they are easier to remember. The Domain Name System (DNS) translates IP addresses into easily recognizable names. Examples: IP address: 72.64.56.86 Domain name: www.microsoft.com
- 27. Domain Names Each domain name is unique. It consists of letters and numbers separated by dots and includes two or more words (labels). The last label in a domain name is usually a two- or three-letter code called a top-level domain. Example: www.microsoft.com Server (Host) Name Registered Company Domain Category Domain Name (Top-Level Domain)
- 28. Domain Name Syntax A domain name, read left to right, specifies general divisions, then specific companies, and individual computers (web servers or e-mail servers) com = a commercial site microsoft = the name registered by the company www = the name of the web server at the company, also called the web site host
- 29. Domain Names A fully qualified domain name (FQDN) is the complete domain name of an Internet computer. It provides enough information to covert the domain name to an IP address. Top-Level Domains .com = commercial or company sites .edu = educational institutions .gov = U. S. civilian government .mil = U. S. military .org = organizations .net = network sites, including commercial ISPs .int = international organizations Two-Letter Country Codes – categorize domains by country or region. For example: us = United States au = Australia
- 30. Addresses on the Web: IP Addressing Each computer on the internet does have a unique identification number, called an IP (Internet Protocol) address. The IP addressing system currently in use on the Internet uses a four-part number. Each part of the address is a number ranging from 0 to 255, and each part is separated from the previous part by period, For example, 106.29.242.17
- 31. IP Addressing The combination of the four IP address parts provides 4.2 billion possible addresses (256 x 256 x 256 x 256). This number seemed adequate until 1998. Members of various Internet task forces are working to develop an alternate addressing system that will accommodate the projected growth. However, all of their working solutions require extensive hardware and software changes throughout the Internet.
- 32. Domain Name Addressing Most web browsers do not use the IP address t locate Web sites and individual pages. They use domain name addressing. A domain name is a unique name associated with a specific IP address by a program that runs on an Internet host computer. This program, which coordinates the IP addresses and domain names for all computers attached to it, is called DNS (Domain Name System ) software. The host computer that runs this software is called a domain name server.
- 33. Domain Name Addressing Domain names can include any number of parts separated by periods, however most domain names currently in use have only three or four parts. Domain names follow hierarchical model that you can follow from top to bottom if you read the name from the right to the left. For example, the domain name gsb.uchicago.edu is the computer connected to the Internet at the Graduate School of Business (gsb), which is an academic unit of the University of Chicago (uchicago), which is an educational institution (edu). No other computer on the Internet has the same domain name.
- 34. Uniform Resource Locators The IP address and the domain name each identify a particular computer on the Internet. However, they do not indicate where a Web page’s HTML document resides on that computer. To identify a Web pages exact location, Web browsers rely on Uniform Resource Locator (URL). URL is a four-part addressing scheme that tells the Web browser: What transfer protocol to use for transporting the file The domain name of the computer on which the file resides The pathname of the folder or directory on the computer on which the file resides The name of the file
- 35. Structure of a Uniform Resource Locators http://www.chicagosymphony.org/civicconcerts/index.htm protocol Domain name pathname filename http => Hypertext Transfer Protocol
- 36. HTTP The transfer protocol is the set of rules that the computers use to move files from one computer to another on the Internet. The most common transfer protocol used on the Internet is the Hypertext Transfer Protocol (HTTP). Two other protocols that you can use on the Internet are the File Transfer Protocol (FTP) and the Telnet Protocol
- 37. How to find information on the Web? A number of search tools have been developed and available to you on certain Web sites that provide search services to help you find information. Examples: Yahoo www.yahoo.com Excite www.excite.com Lycos www.lycos.com AltaVista www/alta-vista.com MSN WebSearch www.search.msn.com
- 38. How to find information on the Web? You can find information by two basic means. Search by Topic and Search by keywords. Some search services offer both methods, others only one. Yahoo offers both. Search by Topic You can navigate through topic lists Search by keywords You can navigate by entering a keyword or phase into a search text box.