Computer Information Technology – Section 3-1

The Internet Objective: To understand the design of the Internet and basic terms associated with Windows Internet Explorer and IE settings

Question What is the internet?

The Internet The Internet is a global system of interconnected computer networks that interchange data by packet switching using the standardized Internet Protocol Suite (TCP/IP). Now consists of millions of private and public, academic, business, and government networks linked by copper wires, fiber-optic cables, wireless connections, and other technologies.

The Internet The Internet looks like this: maps/testmaps/ D.2048x2048. png maps/testmaps/ D.2048x2048. png Colors: Asia Pacifica - Red Europe/Middle East/Central Asia/Africa - Green North America - Blue Latin American and Caribbean - Yellow RFC1918 IP Addresses - Cyan Unknown - White

A Brief History of the Internet The Internet began as ARPAnet, a U.S. Department of Defense project to create a nationwide computer network that would continue to function even if a large portion of it were destroyed in a nuclear war or natural disaster USSR launches Sputnik US forms the Advanced Research Projects Agency (ARPA to establish US lead in science and technology applicable to the military

A Brief History of the Internet 1962 –J.C.R. Licklider of MIT pictured a globally interconnected set of computers through which everyone could quickly access data and programs from any site. He called it the "Galactic Network" concept Thomas Merrill and Lawrence G. Roberts connected a computer in Massachusetts one in California with a low speed dial-up telephone line creating the first wide-area computer network The physical network was constructed linking four nodes: University of California at Los Angeles, SRI (in Stanford), University of California at Santa Barbara, and University of Utah

A Brief History of the Internet October 29, 1969 – The first message is send on the ARPANET. This record is an excerpt from the log at UCLA: I was supervising the student/programmer Charley Kline (CSK) and we set up a message transmission to go from the UCLA SDS Sigma 7 Host computer to the SRI SDS 940 Host computer. The transmission itself was simply to "login" to SRI from UCLA. We succeeded in transmitting the "l" and the "o" and then the system crashed! Hence, the first message on the Internet was “lo". We were able to do the full login about an hour later – The first 15 nodes are created on ARPANET

A Brief History of the Internet 1971 – The Creeper virus was first detected on ARPANET. Creeper was an experimental self- replicating program written by Bob Thomas at BBN Technologies. Creeper gained access via the ARPANET and copied itself to the remote system where the message, "I'm the creeper, catch me if you can!" was displayed. The Reaper program was created to delete Creeper Ray Tomlinson modifies program for ARPANET where it becomes a quick hit. sign was chosen for addresses.

A Brief History of the Internet First international connections to the ARPANET ARPANET grinds to a complete halt on October 27 th due to a virus 1982 – On September 19, 1982 Scott Fahlman, a computer scientist and Professor at Carnegie Mellon University, suggested to students that :-) be used to denote a joke in online posts. He made the suggestion, along with :-( for serious items.

A Brief History of the Internet The U.S. National Science Foundation (NSF) initiated the development of the NSFNET which, today, provides a major backbone communication service for the Internet – The term “Surfing the web” is coined by Jean Armour Polly 1994 – You can order pizza from Pizza Hut online

The Internet Definitions Browser: The tool used to access the internet. Examples are Internet Explorer, Firefox, Safari and now Chrome. Hyperlink: A word, phrase or picture that when clicked will take the user to another location. HTML (HyperText Markup Language): The language of the web URL (Uniform Resource Locator): Tells where a file is located among all the computers that are part of the Internet Format: protocol://domain/path

The Internet Definitions - URL protocol://domain/path Protocol: tells the computer what kind of coding to expect. (hypertext transfer protocol) is the most common ftp:// (File Transfer Protocol) Domains:.com for commercial,.gov for government,.edu for educational institution,.org for organization,.mil for military, and.net for network. Can also reflect the country (

How Web Pages Work When you go to a web page a number of things happen: 1. The source code for the page is downloaded from the web site. This HTML file contains the text of the page. Your browser reads the code and starts displaying it while it asks for any other files that are used in the page, such as images, sound files, and attached files for scripts and stylesheets. The browser receives these one at a time. 2. Tables: Tables cannot be displayed until the rows and column sizes have been calculated. 3. Images are downloaded.

How Web Pages Work Things stored on your computer: 1. Cache: The browser stores all the files it receives from the internet on your hard drive in the browser's cache. This way pages can be displayed much quicker the next time it is accesses. 2. Cookies: Cookies are small text files sent by a server to a browser and then sent back unchanged each time the web site is accessed. HTTP cookies are used for authenticating, session tracking (state maintenance), and maintaining specific information about users, such as site preferences or the contents of their electronic shopping carts.

Windows IE Settings The Internet Options (Tools->Internet Options...) contains many different settings that affect the way Internet Explorer (IE) behaves. Most of these are not often changed from the default settings but some you can change.

Windows IE Settings – Homepage You can set the homepage by entering a web site address here or you use whatever page you currently have open by clicking the “Use Current” button. You can have more than one homepage open when IE starts.

Windows IE Settings – Cleaning Up You can delete cookies or pick what files you want to clean up by clicking this button

Windows IE Settings – Controlling Disk Space Used You can control how your computer accesses web pages and the amount of disk space it will use by clicking on “Settings…” on the previous slide. Set how often your computer will check for new versions of the web pages here Control the cache size here

Windows IE Settings – Security Settings It is best to leave the security settings at the default level.

Windows IE Settings – Privacy Settings You can set privacy settings high but then many web sites will not load. Setting it too low may allow malicious cookies to be loaded on your computer.

Windows IE Settings – Content Connections, Programs and Advanced In general it is a good idea to leave all those settings as defaults.

Windows IE 7 – Reset Button In Windows Internet Explorer 7 there is a “Reset” button on the Advanced tab– This button can be used if your IE has become completely unstable.

Summary The internet is a set of interconnected computer networks. Internet was developed so the network could survive a nuclear war or natural disaster. Be careful changing the settings in IE If IE becomes unusable, click on “Reset” button

Rest of Today Complete Homework 2-5 and 3-1.