新編-Internet8bbsconcept-精品課件

1、Chapter 22Electronic Bulletin Board Service (Newsgroups)Copyright 2019 Pearson/Prentice Hall. All rights reserved.Contents 22.1 Bulletin Board Functionality 22.2 Bulletin Board Topics 22.3 Network News 22.4 Categories 22.5 Accessing Newsgroups 22.6 Moderated Newsgroups 22.7 How Much Is Available? 22

2、.8 The Significance of Newsgroups 22.9 Net EtiquetteObjectivesDescribe an Internet service that extends the use of email to allow an individual to join one or more discussion groups and participate in discussions with other members of the groupSummarize the basic functionalityShow a typical useDescr

3、ibe how the underlying mechanism operatesProvide hints how to use bulletin boards and electronic mail22.1 Bulletin Board FunctionalityAn electronic bulletin board service allows a person to participate in a discussion group focused on a specific topic. The bulletin board service allows an individual

4、 to:Select one or more discussion groups of interestPost a note to the discussion group for others to readPost a note that responds to another noteFind new notes and selectively read them22.1 Bulletin Board Functionality (continued)Conceptually, the Internets electronic bulletin board service fills

5、the same role for Internet users that conventional bulletin boards fill in everyday life.It allows individuals to post notices that others can read.The Internet provides access to thousands of electronic bulletin boards, each of which contains an ongoing discussion about a single topic.22.1 Bulletin

6、 Board Functionality (continued)Electronic bulletin board service combines features of many communication mechanisms:Conventional bulletin board: Anyone is allowed to post a message for others to see.Newspaper: Each message is distributed to many subscribers.Newsletter from a club: The messages focu

7、s on a single topic of interest.Electronic mail service: Copies of each message propagate quickly.Informal discussion at a social gathering: An individual can listen to a conversation, ask questions, occasionally interject small comments, or contribute lengthy statements.22.2 Bulletin Board TopicsIn

8、ternet electronic bulletin boards cover a widely diverse group of topics. Just a few are:General discussion: news, politics, social issuesConsumer interest: reviews, product discussionsPersonal interest: cooking, physical fitness, hobbiesLocal interest: classes, schools, cities, companies, regionsEn

9、tertainment: sports, movies, television shows, musicEducational: computers, math, science, literature, medicine.File sharing: pictures, videos, musicProducts or services22.2 Bulletin Board Topics (continued)Some discussion groups require highly specialized knowledge or are meaningful only to someone

10、 who works at a particular company or lives in a particular country.A bulletin board can be restricted to a few computers, a single organization, or a small geographic area.One bulletin board that contains a discussion of politics in Alberta, Canada is distributed only to nearby sites.22.2 Bulletin

11、Board Topics (continued)When a board is created, interesting side discussions inevitably arise. If there is continued interest in the side topic, the bulletin board can be split.Bulletin boards are easy to create which encourages diversity.22.3 Network NewsThe original electronic bulletin board serv

12、ice available on the Internet is called Network News, often abbreviated NetNews. NetNews uses the term newsgroup to refer to each individual bulletin board (i.e., each discussion group), and article to refer to a message.Each article submitted to a newsgroup takes the form of an electronic mail mess

13、age.Like email, it can be as short as a single line or contain thousands of lines.An article has a header that includes a From line to identify the sender.22.3 Network News (continued)Each article submitted to a newsgroup takes the form of an electronic mail message.Like email, it can be as short as

14、 a single line or contain thousands of lines.An article has a header that includes a From line to identify the sender.22.3 Network News (continued)NetNews originated as part of an early computer network (USENET) that used dial-up modems to exchange information. As networking technology changed, USEN

15、ET participants invented other ways to communicate network news.Most USENET sites acquired Internet access and use that to access NetNews. But, other networks including BitNet and dialup can still be used to access it.22.4 CategoriesThe original NetNews system assigned each newsgroup a unique name c

16、omposed of parts separated by dots.The first part identifies the type of the group.The second part identifies the subjectFollowing parts give particular topics and subtopicsThe newsgroup rec.sport.baseball has the type recreation, the general topic is sports, and the specific subject is baseball.22.

17、4 Categories (continued)A few of the major newsgroup categories available now are:Arts and EntertainmentBusiness and FinanceComputers and The InternetCulturesFamily and HomeGames and GamingHealth and FitnessMusicNews and Current EventsPolitics and GovernmentRegions and PlacesReligionsRomance and Rel

18、ationshipsSchools and EducationScience and TechnologySociety and HumanitiesSports and Recreation22.5 Accessing NewsgroupsOriginally, network news required users to run a separate application program that read or posted news articles. Modern newsgroups are accessible via the web:groups.googlegroups.y

19、ahoousenetGoogle provides access to USENET archives.Many other websites provide access to bulletin board services.22.5 Accessing Newsgroups (continued)Selecting a category is the first step.Next a user would select a topic from a list of topics.Some topics are so large that the topic area is further

20、 divided into specific topics.A user navigates through the topics and subtopics and eventually is presented with a list of newsgroups to choose from.Once a user has found a newsgroup of interest they can save a reference and avoid the navigation process.22.5 Accessing Newsgroups (continued)Example:

21、Topics and subtopicsUnder the category Computers and The Internet would be topics such as:Computer HardwareComputer SoftwareData NetworkingInternetComputer EducationSocial Effects Of Computers Computer Software might divided into subtopics such as:Microsoft WindowsLinuxMac OS22.5 Accessing Newsgroup

22、s (continued)Once a user has joined a newsgroup there are two main ways of finding out if there are new articles.A user can check the newsgroup manually at regular intervals. Many news interfaces allow a user to arrange for an alert to be sent whenever new articles appear. 22.5 Accessing Newsgroups

23、(continued)Reading network news is straightforward. A user selects a newsgroup of interest.The user is presented with a list that identifies the author, date, and subject of each new article.A user clicks on an article to view it.A news article appears in the same general form as an electronic mail

24、message.22.5 Accessing Newsgroups (continued)Submitting an article is as easy as sending electronic mail.A user composes and edits a message.They request that the message be posted to one or more groups. (Each group will appear in the header.)In addition to composing a message from scratch, a user c

25、an form a reply to an existing article. 22.6 Moderated NewsgroupsSome newsgroups permit anyone to submit an article. Posters will range from novices to experts.Some posters will attempt to disrupt the discussion by posting provocative articles. 22.6 Moderated Newsgroups (continued)To limit disruptio

26、ns and compensate for differences in background, some newsgroups are moderated. A moderator will preview all articles submitted to the newsgroup. The moderator can:Submit the article as receivedEdit the article be submissionCombine several articlesReject the article22.7 How Much Is Available? Newsgr

27、oups are extremely popular.In 2019, one commercial site advertised over 120,000 separate newsgroups with more than two million articles available each day. Many companies use internal newsgroups that are only visible to employees of the company.22.7 How Much Is Available? (continued) An accurate cou

28、nt of newsgroups is impossible to obtain for two reasons.There is no single source. Many providers offer bulletin boards.There are many boards that are specific to a single region or country.The number of newsgroups and volume of traffic is so heavy, no individual can participate in all newsgroups.2

29、2.8 The Significance Of Newsgroups Newsgroups enable millions of people to participate in discussions.Bulletin board services provide an opportunity for people with diverse points of view from around the world to offer opinions to a large group. Communities develop on the Internet among people with

30、common interests. These communities are often composed of people that have seldom (or never) met in person.22.8 The Significance Of Newsgroups (continued)Three important characteristics of the communication via newsgroups are:Articles are text so an author can not use tone of voice or gestures to ex

31、press emotion.Articles are seen by so many people that almost any statement will elicit a response.Articles can expire after a few days, so newcomers may be unable to obtain context and history.22.9 Net EtiquetteMembers of a society follow rules of etiquette to keep social interactions civil and dis

32、tinguish normal behavior from insults. Learning etiquette for the Internet is difficult becauseUsers come from diverse cultures, economic backgrounds, and levels of education.Many users do not follow normal rules of courteous discussion.Differences in background often become apparent in subtle ways. 22.9 Net Etiquette (continued)A few simple guidelines help compensate for such differ