Comp4_unit2b_audio_transcript.doc



Introduction to Information and Computer Science: Internet and the World Wide Web

Audio Transcript

Slide 1

Welcome to Introduction to Information and Computer Science: Internet and the World Wide Web. This is Lecture b

The component, Introduction to Information and Computer Science, is a basic overview of computer architecture; data organization, representation and structure; structure of programming languages; networking and data communication. It also includes basic terminology of computing.

Slide 2

The Objectives for Internet and the World Wide Web are to:

Define the Internet and how to connect to it.

Define the World Wide Web and how to access it.

Write effective search queries for Internet search engines, filter the results and evaluate credibility of information.

Discuss security and privacy concerns on the Internet.

Describe ethical issues for the Internet.

Explore online healthcare applications and associated security and privacy issues including HIPAA.

Slide 3

This lecture will cover Internet Service Providers or ISPs [I-S-Ps] and how people and businesses use their hardware and services to connect to the Internet.

Most people have a home Internet connection but do not have any idea how it is set up or how it functions. In addition, almost everyone has heard of Google, Yahoo!, Bing, and others, but many do not know how to use these tools effectively to find information on the Internet. This lecture explains how to use search terms with a search engine to locate specific online information.

Many organizations connect users to the Internet. Providers that connect users to the Internet are commonly referred to as ISPs [I-S-Ps]. These entities are organized as local, regional, and national providers. Local providers connect to regional providers. Local providers may work only in a limited number of cities or even perhaps one city.

Slide 4

Regional providers usually operate in parts of or in a number of states or provinces. Regional providers connect to national providers. National providers provide high-speed data transfer amongst themselves to provide a robust, redundant system. In fact, national providers provide connectivity to every other network on the Internet at no cost.

Slide 5

Since ISPs [I-S-Ps] must maintain equipment and pay salaries, it is understandable that they would provide Internet access for a fee. Fees are based on type of service and connection speed.

Dial-up service costs approximately ten dollars per month and is available almost anywhere in the United States; however it is very slow and not useful for today’s Web. DSL [D-S-L] is much faster than dial-up but is not available in many locations. DSL [D-S-L] is really just dial-up with good copper, meaning that the telephone company or an ISP [ISP] provider is able to speed up that Internet connection. DSL service should cost approximately fifty dollars a month. Cable internet service is usually much faster than DSL [D-S-L] but is only available where cable companies have installed coaxial cable in streets. The average cost for cable internet service is around sixty dollars per month.

Slide 6

ISPs [I-S-Ps] usually provide the equipment required to connect to their service for purchase or a monthly lease fee. This is known as provider equipment. But dial-up connections require a modem on the premises, for example, in a home. A computer connects to the modem and the modem connects to the ISP’s [I-S-Ps] wall connection that provides Internet access.

DSL connections require a DSL modem. Cable connections require a cable modem router, but similar to dial-up, they then need a connection from the modem or router to the ISP’s [I-S-Ps] wall connection to access the Internet.

Slide 7

Private networks also have their own equipment. A private network in a home or business is usually made up of computers, laptops, wireless access points, and switches. All private devices can connect to a switch, with the switch connecting to the ISP’s [I-S-Ps] equipment via a network cable. With this setup, all private devices can access the Internet and share the same Internet connection. Keep in mind that without a fast connection with an ISP [ISP] in this type of setup, all of the private devices will experience slow connections to the Internet.

Slide 8

The next topic is leasing an IP [I-P] address. ISPs [I-S-Ps] lease IP [I-P] addresses to subscribers. A private network—again, in a home or business—usually uses a private IP address range. The ISP [I-S-P] typically leases one public IP [I-P] address per location.

For example, a cable connection has one public IP [I-P] address that is included with the cable fee each month. The ISP’s [I-S-Ps] equipment is provided with that public or that leased public IP address to connect to the ISP’s [I-S-Ps] public network. The ISP’s [I-S-Ps] equipment is also provided with a private IP [I-P] address to connect to the user’s private network. The private IP [I-P] address that is associated with a cable modem router must be in the same range as the other devices in that network.

Slide 9

Leasing IP [I-P] addresses is just part of the picture of IP [I-P] addresses; it is also important to differentiate between a dynamic and a static IP [I-P] address. In the case of dynamic IP [I-P] addressing, the ISP’s [I-S-Ps] equipment is able to translate addressing between the private and public networks—in other words, the private IP [I-P] address and the public IP [I-P] address that must be used to access the Internet.

ISPs [I-S-Ps] generally provide users with an IP [I-P] address that may change from day to day. This is the typical leased, dynamic IP [I-P] address and is included in the monthly fee. Most home IP [I-P] addresses are dynamic. When rebooting an ISP’s [I-S-Ps] equipment (for example, a cable modem router), it may boot back up a different IP [I-P] address. This really is not an important distinction unless a user needs an IP [I-P] address that does not change.

Slide 10

One example of a user needing an IP [I-P] address that does not change is the network administrator who is working from home. In this case, an ISP [ISP] can lease an IP [I-P] address for the duration of a contract. This IP [I-P] address, known as a static IP [I-P] address, will not change.

Most Web sites use static IP [I-P] addresses so that their domain [doh-main] name will be reliably mapped to one IP [I-P] address. Imagine if the domain [doh-main] name of the White House, [w-w-w-dot-whitehouse-dot-guhv], had a dynamic IP [I-P] address that constantly changed. This would mean that the world’s DNS [D-N-S] servers would have to keep track of those changes. That would be pretty tough to do.

ISPs [I-S-Ps] charge more per month for static IP [I-P] addresses. The charges range from approximately five dollars to a hundred dollars a month. ISPs [I-S-Ps] are happy to lease one or more IP [I-P] addresses to individuals for home or business use because they make money by offering this service.

Slide 11

ISPs [I-S-Ps] also provide DNS [D-N-S] services. They provide a first level of DNS [D-N-S] servers so that users can get quick resolution each time a browser is used. ISP [I-S-Ps] DNS [D-N-S] servers connect to global DNS [D-N-S] route servers for help. When they cannot resolve a name to an IP [I-P] address, they use their DNS [D-N-S] servers for a speedier browsing experience.

Slide 12

The next topic is searching the Internet. Search engines search Web pages for information using algorithms.

An example of a search engine is Google. Information includes key words and other information found on Web pages. Note that a search engine is not a Web directory, which is a site that manually lists sites by category. For example, the Web site “Craigslist” offers a Web directory and a search engine.

Slide 13

There are a number of search engine providers, four of which are listed on this slide: Google; Bing, provided by Microsoft; Yahoo! (note that its name does include the exclamation point); and Ask.

Slide 14

How does a search engine function? Search engines gather data. Web crawler programs are programmed with proprietary algorithms to gather HTML coding on Web pages. An algorithm is a set of instructions designed to logically solve a problem or reach a desired goal.

Search providers own proprietary algorithms that provide distinct search results. In other words, Google’s algorithm is different than Bing’s algorithm.

A company’s algorithms are closely guarded secrets because each believes that their algorithm is better than that of their competitors and provides the results that people would most commonly look for. It is true that some algorithms are better than others.

Slide 15

Search providers use crawler programs to analyze Web pages, employing their proprietary algorithms to do this. The gathered data is then analyzed, indexed, and used to provide search results. The indexed data is stored in a database and is owned by the search provider. Search engine software searches its indexed data based on a user’s search criteria.

Slide 16

There are a number of ways to use a search engine. First, a search can be launched using a phrase; this is known as a query. In this case, the engine analyzes its indices [in-duh-seez], looking for pages that most closely match the information entered.

For example, type “What is the Internet?” as shown in the slide (but entered without the quotes) in a search line. After clicking to search, select the Wikipedia entry near the top of the page.

Slide 17

Users can employ a wildcard such as the asterisk, in a search phrase. Searching for “search engine list 20* [twenty star],” again without the quotes, returns Web sites listing search engine rankings for the years 2000 through 2099. Notice that 20* [twenty star] entered into a search engine phrase indicates that the word has to start with “20” and that any number of characters may appear after that, as long as it starts with 20. Try this by opening a search engine and type in “search engine list 20* [twenty star]”; the rankings of search engines from 2000 to 2009 will appear.

Slide 18

To get the best search results, users need Boolean [boo-lee-uhn] operators, which are words that can restrict or even augment the search phrase. The words are “and,” “or,” and “not.”

Here’s a search using the Boolean [boo-lee-uhn] operator “and.”

Searching for “cardiac AND arrest,” again without the quotes, will list pages containing both of the words, not just one word or the other. Most search engines will begin with “cardiac arrest.” Once they exhaust that search, they will look for “cardiac” and then “arrest.” Substituting the word “OR” for “AND” (for example “cardiac or arrest,” again without the quotes), the result will be a list of Web pages containing either or both words.

How about the keyword “NOT”? Searching for “cardiac and arrest, not flu,” again without the quotes, will list Web pages containing “cardiac” and “arrest,” but not “flu.” Use the word “not” to restrict search results.

Slide 19

Some key tips on searching for information on the Web include the following:

Web searching is not case sensitive. Try searching for information related to the state of Oregon. Capitalize the “O” in one search and then enter it with a lowercase “o" in another search to see the difference in the results.

Be specific when entering search information. Do not simply search for the word “car,” which is a generic noun. Be more specific by adding the make, model, and year of the vehicle in the search.

Use short search phrases of two to three words when possible. When searching the Web, less is often more.

Searching with phrases in quotes restricts the search results. The next slide will look at this in a little more detail.

Slide 20

Entering the phrase, “Phantom of the Opera” in quotes in a search engine will return Web pages that contain that phrase in that specific word order, with all of those words. Searching for Phantom of the Opera without quotes will return Web pages that contain the words “phantom,” and/or “opera,” and so on, in no particular order.

Slide 21

What does it mean when a Web site is displayed at the top of a search results list? Such a ranking means that key words found on the Web site by the search engine crawler closely match the phrase entered in a search. Popular Web sites, those that are visited most often by people and devices that use the Internet, match the search phrase. Additionally, paying sites may appear at the top or side of the search results, very close to the unpaid sites. Often the “paid for” search result will appear in a colored box or have a special font applied to it. Clicking on that “paid for” result means that the owner of that Web site typically has to pay the search provider a fee. For example, the vendor may pay a penny per click and then pay more if the user visits the site and purchases something.

Slide 22

This concludes Lecture b of the Internet and World Wide Web. In summary, this lecture showed that devices connect to the Internet through an interconnected network of ISPs [I-S-Ps]; that ISP [ISP] fees include the use of their equipment, which is used to connect a network to the Internet; that ISPs [I-S-Ps] provide IP [I-P] addresses and DNS [D-N-S] services to subscribers; and that people search for content on Web pages through the use of search engines, which are provided by a number of different companies.

Slide 23

This lecture also discussed that search terms can include Boolean operators to augment or limit search engine results; that search terms can be enclosed in double quotes, which limits search engine results; and that search engine results are influenced by search terms and payments to search providers by vendors.

Slide 24

References slide. No audio.

................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download