1 / 27

Introduction to Information and Computer Science

Introduction to Information and Computer Science. Internet and the World Wide Web. Lecture a.

wirt
Download Presentation

Introduction to Information and Computer Science

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Introduction to Information and Computer Science Internet and the World Wide Web Lecture a This material (Comp4_Unit2a) was developed by Oregon Health and Science University, funded by the Department of Health and Human Services, Office of the National Coordinator for Health Information Technology under Award Number IU24OC000015

  2. Internet and the World Wide WebLearning Objectives • Define the Internet and how to connect to it (Lecture a and b) • Define the World Wide Web and how to access it (Lecture a and b) • Write effective search queries for Internet search engines, filter the results, and evaluate credibility of information (Lecture b) • Discuss security and privacy concerns on the Internet (Lecture c) • Describe ethical issues for the Internet (Lecture c and d) • Explore online healthcare applications and associated security and privacy issues including HIPAA (Lecture d) Introduction to Information and Computer Science Internet and the World Wide Web Lecture a Health IT Workforce Curriculum Version 3.0/Spring 2012 2

  3. What is the Internet? • According to Wikipedia: • “The Internet is a global system of interconnected computer networks that use the standard Internet Protocol Suite (TCP/IP) to serve billions of users worldwide.”(Wikipedia, 2010) • The hardware that makes up the Internet is cabling, routers, switches, servers, and computers that host documents, audio, video, and others. Introduction to Information and Computer Science Internet and the World Wide Web Lecture a

  4. What is the Internet (continued) • In other words, the Internet is a large network made up of many smaller networks: • Computers connect to the Internet via an ISP (Internet Service Provider) such as AT&T, Bell South, CenturyLink™, Verizon, and others Visualization of the various routes through a portion of the Internet From “The Opte Project” (The Opte Project , c 2007, CC BY 2.5). Introduction to Information and Computer Science Internet and the World Wide Web Lecture a

  5. The Origins of the Internet • The Internet has its roots in the US Government’s desire to still be able to communicate, even in the event of a nuclear strike. • ARPANET: Advanced Research Projects Agency Network • The original Internet consisted of four computer (servers) operating at UCLA; UC-SB; Stanford (SRI International); and the Univ. of Utah in 1969 Introduction to Information and Computer Science Internet and the World Wide Web Lecture a

  6. The Internet Today • The world quickly saw its benefits and the Internet continued to grow, especially in the mid- 1990s • In 1995, approximately 16 million people were using the Internet • Today, more than 1.8 billion people use the Internet Introduction to Information and Computer Science Internet and the World Wide Web Lecture a

  7. The Internet Spawns the World Wide Web • They are not the same thing! • The WWW is often referred to as the “Web” • According to Wikipedia: • “The Web is one of the services that runs on the Internet. It is a collection of interconnected documents and other resources, linked by hyperlinks and URLs.” • A URL (uniform resource locator) is an address typed into a browser’s address line, such as www.whitehouse.gov Introduction to Information and Computer Science Internet and the World Wide Web Lecture a

  8. Who Created the Web? • British scientist Tim Berners-Lee created the WWW in 1989 by introducing a Web browser and Web page coding (Bojārs, U., 2005, CC BY 2.5) Introduction to Information and Computer Science Internet and the World Wide Web Lecture a

  9. How Does the Web Work? • A browser is a software program that lets the user interact with the Web by facilitating connection to other Web servers over the Internet • The browser uses HTTP to communicate with Web servers to get Web page content • The Web server sends HTML coding back to the browser, which translates the HTML coding for display on a monitor Introduction to Information and Computer Science Internet and the World Wide Web Lecture a

  10. HTML - The Language of the Web • Web pages are text files written in the HTML programming language • HTML example for a simple Web page 2.1 Figure: Diagram of an HTML example for a simple Web page. (PD-US, 2010) Introduction to Information and Computer Science Internet and the World Wide Web Lecture a

  11. The World’s First Web Server • This NeXT Computer was used by Sir Tim Berners-Lee at CERN and became the world's first Web server (User: CoolCeaser, 2005, CC BY 3.0) Introduction to Information and Computer Science Internet and the World Wide Web Lecture a

  12. Who Owns the Web? • No entity owns the Internet, but people and organizations own the devices that connect to the Internet and form the WWW • For example, Google’s experience in China (Wikipedia Web page entitled, Internet Censorship in the People’s Republic of China) Introduction to Information and Computer Science Internet and the World Wide Web Lecture a

  13. Standardized Communications • Internet protocols are a global standard, ensuring interoperability between hardware and software devices • Protocols such as HTTP allow any browser to talk to any Web server • TCP/IP transports HTTP across the Internet for delivery to its destination Introduction to Information and Computer Science Internet and the World Wide Web Lecture a

  14. Internet Addressing Basics • All Internet communication uses IP addressing • The Internet expects each communicating device (known as a host) to possess an Internet Protocol (IP) address and subnet mask, which is a group of numbers in the format of: • IP address: 192.168.10.1 • Subnet mask: 255.255.255.0 Introduction to Information and Computer Science Internet and the World Wide Web Lecture a

  15. Internet Addressing Basics (continued) • This host is in the 192.168.10.x network • This network can legally have addresses in the range of 192.168.10.1 through 192.168.10.254 • Networking devices and software use 192.168.10.0 and 192.168.10.255 for routing and communication • Valid numbers are in the range of 0-255 Introduction to Information and Computer Science Internet and the World Wide Web Lecture a

  16. How to Obtain an IP Address • Some IP addresses can be purchased or leased and used by the owner of that IP address or IP address range • Referred to as public IP addresses • Most IP addresses are public addresses • Other IP addresses can be used by anyone • Referred to as private IP addresses • Examples include 10.0.0.0, 172.16.31.0, and 192.168.0.0 • IP addressing is beyond the scope of this unit Introduction to Information and Computer Science Internet and the World Wide Web Lecture a

  17. Introducing Domain Names • The Internet supports the use of domain names • Imagine trying to navigate the Internet using IP addresses and not names! • Since people remember names better than numbers, the domain naming system (DNS) was created Introduction to Information and Computer Science Internet and the World Wide Web Lecture a

  18. DNS & IP Work Well Together • DNS maps an IP address to a domain name • When you visit http://www.whitehouse.gov, your computer must first figure out this Web site’s IP address • One IP address for this site is 65.126.84.121. This Web site is probably associated with many IP addresses • Domain name resolution is accomplished through the use of DNS servers, which are located throughout the world Introduction to Information and Computer Science Internet and the World Wide Web Lecture a

  19. DNS & IP Work Well Together (continued) • All domain names are mapped to an IP address and stored on global and privately-owned DNS servers • Global DNS servers are known as “root servers” and work together to map the globe’s names to their IP addresses • When your browser learns the destination site’s IP address from the DNS server, communication begins! Introduction to Information and Computer Science Internet and the World Wide Web Lecture a

  20. What is a Domain Name? • People and organizations can purchase a domain name from ICANN • According to Wikipedia: • “A domain name is an identification label that defines a realm of administrative autonomy, authority, or control on the Internet, based on the Domain Name System (DNS).”(Wikipedia, 2010) • Domain names consist of three pieces: • The domain name, www.whitehouse.gov, indicates a government site with the purchased domain name of “whitehouse,” found on the WWW Introduction to Information and Computer Science Internet and the World Wide Web Lecture a

  21. Connecting to the Internet • Devices commonly connect to the Internet via dial-up, broadband, Wi-Fi, satellite, and 3G • Dial-up–copper phone lines connect to an ISP’s modem. Limited to a speed of 56 Kbps • The slowest connection type! • Broadband–higher quality copper phone lines, coaxial cable, or fiber optic connection type • Faster than dial-up and in the approximate range of 768 Kbps and higher Introduction to Information and Computer Science Internet and the World Wide Web Lecture a

  22. Connecting to the Internet (continued) • Wi-Fi–wireless (radio frequency) connection type. • Wi-Fi refers to the IEEE 802.11 standard governing wireless technologies • Typically used to connect laptops to WAPs. The WAP is connected to the wired network to gain access to the Internet • Also used extensively by hotels and airports • Wireless speeds range from 1 Mbps to 200+ Mbps, depending on a variety of factors Introduction to Information and Computer Science Internet and the World Wide Web Lecture a

  23. Connecting to the Internet (continued) • Satellite–Connection to a ground satellite dish (antennae) and the satellite relays signals to a satellite orbiting the earth. Then the orbiting satellite relays the signal to another ground satellite dish • Can be somewhat slow because of the time it takes to make a round trip. The loss of speed is known as “latency.” • 3G and 4G – The 3rd and 4th Generation of standards governing mobile telecommunications • Speeds range from 2 Mbps to 28 Mbps. Introduction to Information and Computer Science Internet and the World Wide Web Lecture a

  24. Internet and the World Wide WebSummary – Lecture a • The Internet is a global system of interconnected networks • The World Wide Web functions within the Internet and is made up of HTML Web pages and linked documents, which are stored on Web servers • Internet communications are standardized around the IP protocol • An IP address can be leased from an ISP Introduction to Information and Computer Science Internet and the World Wide Web Lecture a

  25. Internet and the World Wide WebSummary – Lecture a • The Internet relies on DNS to translate, or resolve a domain name to an IP address • Computers connect to the Internet through the services provided by ISPs • ISPs provide access to the Internet via dial-up, broadband, Wi-Fi, satellite, and 3G connections Introduction to Information and Computer Science Internet and the World Wide Web Lecture a

  26. Internet and the World Wide WebReferences – Lecture a References Barretto, M. The count reached 1 Billion Internet Users Worldwide. [Online]. 2009, January 27; [cited 10 July 2010]; Available from: http://lab.77agency.com/marketing-analysis/the-count-reached-1-billion-internet-users-worldwide-1069/. Domain name. Wikipedia [free encyclopedia on the Internet]. 2010 July 10; [cited 12 July 2010]; Available from: http://en.wikipedia.org/wiki/Domain_name. Evans A, Martin K, Poatsey MA. Chapter 1: Why Computers Matter to You. In: Technology in Action: Complete. 7th ed. New Jersey: Prentice Hall; 2010. Internet. Wikipedia [free encyclopedia on the Internet]. 2010 July 10; [cited 10 July 2010]; Available from: http://en.wikipedia.org/wiki/Internet. Internet censorship in the People's Republic of China. Wikipedia [free encyclopedia on the Internet]. 2010 July 11; [cited 12 July 2010]; Available from: http://en.wikipedia.org/wiki/Internet_censorship_in_the_People%27s_Republic_of_China. Internet World Stats. Internet Usage Statistics. 2009 December 31; [cited 10 July 2010]; Available from: http://www.internetworldstats.com/stats.htm. Parsons JJ, Oja D. Chapter 1: Computers and Digital Basics. In: New Perspectives on Computer Concepts 2011: Comprehensive. 13th ed. Boston: Course Technology; 2010. Shelley GB, Vermaat ME. Chapter 1: Introduction to Computers. In: Discovering Computers 2011: Introductory. 1st ed. Boston: Course Technology; 2010. Introduction to Information and Computer Science Internet and the World Wide Web Lecture a

  27. Internet and the World Wide WebReferences – Lecture a References Tim Berners-Lee. Wikipedia [free encyclopedia on the Internet]. 2010 June 10; [cited 12 July 2010]; Available from: http://en.wikipedia.org/wiki/Sir_Tim_Berners-Lee. Web search engine. Wikipedia [free encyclopedia on the Internet]. 2010 July 11; [cited 12 July 2010]; Available from: http://en.wikipedia.org/wiki/Web_search_engine. World Wide Web. Wikipedia [free encyclopedia on the Internet]. 2010 July 12; [cited 12 July 2010]; Available from: http://en.wikipedia.org/wiki/World_Wide_Web. Charts, Tables, Figures 2.1 Figure: Diagram of an HTML example for a simple Web page. (PD-US, 2010) . Images • Slide 4: The Opte Project [image on the Internet]. The Opte Project (c2007). Accessed Jan 2012 from: http://en.wikipedia.org/wiki/File:Internet_map_1024.jpg. Attribution 2.5 Generic (CC BY 2.5). • Slide 8: Tim Berners-Lee [image on the Internet]. (c2005). Accessed Jan 2012 from: http://en.wikipedia.org/wiki/Sir_Tim_Berners-Lee. Attribution 2.5 Generic (CC BY 2.0). • Slide 11: Photo of the World’s First Web Server [image on the Internet]. User:Coolcaesar (c2005). Accessed Jan 2012 from: http://en.wikipedia.org/wiki/File:First_Web_Server.jpg. Attribution 3.0 Generic (CC BY 3.0). Introduction to Information and Computer Science Internet and the World Wide Web Lecture a

More Related