1.  Learn the Net. and, especially, its "The Animated Internet".
2. Weblogs/Blogs.
1. (NPR) 10th anniversary of "Blog".
   
2. Add Weblogs and Web Services to PreAssessment3.
   

LEARNING MODULE III INTERNET SERVICES

        In section 2.2. of the Overview of Cyberspace, we specified three "categories of services" provided by the internet, ______________ (1), ________ ________(2), and _______ _______(3) .  Technically each is distinguished by the type of protocol used by Internet client applications to access these services; we will investigate these protocols in more detail in Learning Module IV, INTERNET PROTOCOLS.  However, in the following presentation we will focus of the services themselves.   Independent learners should read the objectives and sequence of presentations, summary, then the Study Guide for this learning module.

The Objectives of this learning module are:

1. to present the Internet services, introduced in Learning Module I, in more detail than LM I.  (This is the final treatment, in this course, of this subject.)
2. to distinguish between those services that are currently popular (e.g. the Web) and those that are mainly of historical interest (e.g. Gopher and WAIS).
3. to focus on the World Wide Web, the the dominant service of the Internet and to emphasize the effect that the advent of the Web has had on telecommunications in general and other services in particular.

1. INFORMATION RETRIEVAL SERVICES:
• 1.1 THE WORLD WIDE WEB
• 1.2 GOPHER
• 1.3 WAIS
2. RESOURCE ACCESS
• 2.1 FILE TRANSFER
• 2.2 REMOTE LOGON
3. COMMUNICATIONS
• 3.1 E-MAIL
• 3.2 MAILING LISTS
• 3.3 NEWSGROUPS
• 3.4 CHAT
• 3.5 TELECONFERENCING

1.  INFORMATION RETRIEVAL SERVICES OF THE INTERNET:

In section 2.2. of the Overview of Cyberspace, we specified three "information retrieval services", _____________________ (4), _______(5), and _______(6) that are unique to the Internet.  GOPHER and WAIS, are no longer subjects of COSC 120 labs because GOPHER sites and WAIS sites have by now almost been completely replaced by equivalent Web sites.  The hands-on activities involving the Web are spread of an introduction to browsing in Lab 1, developing, publishing, and managing Web sites in Labs 4-6, and searching for Web sites in the course project.
 

1.1 THE WORLD WIDE WEB:

        The World Wide Web (Web, WWW, or W3) is a distributed, hypermedia information retrieval system. It is not an application nor protocol like Telnet, FTP and Gopher (HTTP is the protocol of the Web.), but rather an invisible network (or web) within the larger network of the Internet. It can be thought of, at least two ways:

• as a network of computers, i.e. a subnet of the Internet whose protocol is ______(7)and
• as a web of documents, i.e. a distributed database of multimedia documents, written in ______(8), whose content is accessed by hyperlinks.

1. another location within the same HTML document, i.e. a "target" or "anchor" in the same HTML file.
2. another document on the same computer (typically, but not necessarily another HTML document (file)) , or
3. another document on another computer (________(9) server) on the Internet. The documents are accessed by a client program, called a __________(10).

1.1.1 Early History of the World Wide Web:

1. The concept of the Web is attributed to Tim Berners-Lee of CERN, the European Laboratory for Particle Physics in Geneva, Switzerland, who first proposed it in 1989; CERN developed the first WWW prototype in 1990. (Streaming multimedia interview on ZDTV's "Big Thinkers"; unfortunately not currently accessible,  I have both a VHS and DVD copy of these which I hope to show to the class.)  In the document About the World Wide Web, he wrote about his vision the Web, "the universe of network-accessible information, an embodiment of human Knowledge." You can access that document at
http://www.w3.org/hypertext/WWW/WWW Berners-Lee wanted a single means of access (one client) to the diverse services of the Internet (See Figure WWW-2.)

2. To overcome problems of incompatibility between different sorts of computers, the WWW introduced the principle of "universal readership," which states that networked information should be accessible from any type of computer in any country, with one easy-to-use program.
3. The first Web documents were only hypertext, and thus not so inspiring as the multimedia documents that make up the Web of today. The first multimedia browser, Mosaic, was developed by Marc Andreesen, Eric Bina, and others at the National Center for Supercomputer Applications (NCSA) at the University of Illinois. However, it was not until Andreesen left NCSA, co-founded Netscape Communications, and developed the browser, __________ __________(11) that the popularity of the Web really exploded.

1. Multiple client applications were needed to access the different types of Internet content.
1. If a user wanted to read a Usenet newsgroup article, he or she would have to run a newsreader program, but to read a file mentioned in the article, FTP had to be used to download it; if the downloaded file were a photograph, yet another application, a viewer, was needed to display the picture. (See Figure WWW-2.)
2. A single tool was needed that gives people access to all the resources provided by the Net. That tool was Berners-Lee’s browser that makes it possible to explore almost every part of the Net without ever needing to worry about changing programs. (See section 1.4.D below.)
2. It was necessary to simplify the addresses of computers and their files on the Internet.
1. Before the Web in order to use an FTP client one had to key in the arcane numeric IP address (four numbers separated by periods) followed by directory paths, and finally the file name before one could download the file. An example might look like 131.118.83.1/htracy/ftpfiles/index.ftp
1. To rectify this, Berners-Lee decided to adopt the hypertext concept made popular by the Apple Macintosh application HyperCard. (See section1.3.C.b, below.)
2. Even the address complexity has been avoided by replacing numeric IP addresses with URLs (Universal Resource Locators), a systematic text-based addressing system.  (See section 1.5.B.)
3. Before the Web, all information was text-based. Browsers, with GUIs, overcame this shortcoming and can now handle multimedia (graphics, video clips, and sounds), although some file formats (See Learning Module V.) require "helper applications", i.e. programs, designed to manipulate a specific file format, that can be "plugged in" to a browser; see section 1.1.4.E, below.

1. The Web facilitates multiple protocol support. (See Figure WWW-2.) To access any Internet service, all one needs to do is type the URL type (associated protocol or keyword) followed by the file location, e.g.


http://faculty.frostburg.edu/<path to some HTML File>

accesses an unspecified Web page on FSU’s web server; the http designates the URL type. (Sometimes, as in the case of http, this is the same as the protocol.) The www.fsu.umd.edu is the domain name which identifies the server and <path to some HTML File> is a generic symbol for a sequence of directory names, called the "file path", ending by a specific file name.

Other URL types include  ftp, telnet, mailto, news, gopher,  wais, etc.; when they are typed into a browser, it invokes the associated protocol and accesses that Internet service.
1. The Web is designed to provide access to distributed, dynamic, and platform independent information.
1. A distributed system is one in which computers are connected by a communications network where each computer system is designed to handle its local workload while the network supports the system as a whole, based on the client-server model. It is the opposite of a centralized multiuser computer like a mainframe. The amount of information which can be stored on the Internet is limited only by the number of computers and their collective storage space. Thus the Net effectively has an infinite storage capacity!
2. The content of the Net is constantly changing and evolving. This dynamic nature of the Internet means that users have access to the most up-to-date information possible, like a living, unlimited, multimedia encyclopedia. The disadvantage of dynamic information is that it can disappear if the network connection is blocked or the file is moved (or removed) from its server.
3. What makes the Web so radically different from other computer facilities is that it can be accessed from any kind of computer and any operating system. All one needs is a browser designed for the operating system you use; the browser GUI is thus the same on all computers. The Web documents are written in HTML, a platform independent language, which means they can be stored on and accessed from any kind of computer system, as long as it implements TCP/IP.
2. Unlike most Internet services, access to Web information is user friendly in that it is interactive and easily explored.
1. What makes the Web so interactive is its ability to accept information from users and perform various actions based on these responses. This is accomplished by using forms, a special Web page that includes text fields, check boxes, radio buttons, menus, and popup lists that give the user the ability to interact with the Web server.
2. Web access is based on hypertext which allows hyperlinks to be embedded in text; this has been extended, in "hypermedia", to embed hyperlinks in graphic images as well. It is now possible to move between Net documents by pointing and clicking, without needing to know the physical name of the file or even the address of the computer on which it is stored.
3. The Web facilitates nonlinear access thus providing user control over the sequence of reading.  HTML makes it possible to embed hyperlinks into the text, thus creating "hypertext", i.e. text that also is linked to other text so that the reading sequence depends on choices of the user.  The hyperlinks can use different protocols making it possible to access documents with various Internet protocols.  Thus the browser concept integrated the use of all Internet protocols into one client.

1. Web information is normally contained in HTML documents. HTML (Hypertext Markup Language; see Learning Module VI) allows one to "program" a document by describing its layout, contents, and hyperlinks with "style tags" embedded in text files. At first, HTML documents were created using a pure ASCII text processors; the style tags were typed in along with the regular text. Now, sophisticated HTML editors (e.g. Netscape Composer, part of the Netscape Communicator suite)can generate HTML using WYSIWYG GUIs.
1. A Web page is an HTML document that is made available, by a Web server, for access via the Internet.
2. A home page is the default starting point or organizational center for any collection of Web pages.  It typically has the name index.htm or index.html and is opened automatically by the Web server when a Web site (See next.) is accessed.
3. A Web site is an integrated collection of Web pages which is normally collected in a single directory (folder) called a Web account.
2. A hyperlink is text (hypertext) or an image (hypergraphic)  that is distinguishable as a link to another location in the same document or to another HTML document. The browser is designed to detect when the user clicks the mouse on a hyperlink; it then locates the destination and downloads it into the browser. The convention for designating hypertext is the underline, so underlines should not be used in hypermedia documents for other reasons. There are three basic types of hyperlinks:
1. absolute links are used to access a different Web page and thus must give the absolute URL, i.e. the complete URL, of that document.  These typically lead to the beginning of the Web page unless they contain a target. (See the next item.)
2. target links point to a named "target" or "anchor" placed within a Web page; when incorporated into an absolute link, this allows a link to go to any point within any Web page.
3. relative links are pointers to another file relative to the location of the current file, i.e. the document where the link originates.
1. When a link is created between HTML documents on the same computer it is a relative link because it is specified relative to the document in which the link originates. This is typically done, in an HTML authoring program, by selecting a link button and browsing to the HTML document to which the link is made.
2. When an HTML document is published, the relative links still work as long as the organization of the files on the server is the same as that on the computer where they were created.   Therefore, all developers need to do is make their links work on their local storage, then, if the file structure is uploaded intact (i.e. it is a perfect reproduction of the original file structure) the relative links between all files on the server will work.
Illustrations of these different link types can be found in this document.  Investigate the source of this page (You will have to open the page in its own window and then select Page Source from the View menu.) and you will find examples of all the above links.  Look for the tags that begin with <a href=; these are all hyperlinks.  If what follows the equal sign is (1) a complete URL, it is an absolute link, (2) # followed by text, it is a target link, or (3) a path name followed by a file name, it is an absolute link.
3. Bookmarks (sometimes called "hot links") are links that are saved in a HTML file so they can be retrieved and traversed in the future.

4. HyperText Transport Protocol (HTTP) is a member of the TCP/IP protocol suite that defines how to identify, send, and retrieve Web documents. (TCP/IP is covered in more detail in Learning Module IV)
5. A browser is ________(12) software for viewing HTML documents and navigating hyperlinks to other documents, not necessarily on the Web.
6. Plug-ins and Helper applications are programs that can be used by a browser to overcome its inadequacies
1. Plug-ins typically are software components that are added to the browser itself.  For example, if a browser does not support the format of an image or sound file (See Embedded Files in the next section.) that is embedded in an HTML file, the browser may use a plug-in specifically designed to view that type of image or play that sound. A popular example is Real Audio which allows one to listen to streaming audio. Although browsers typically come bundled with some plug-ins, they usually have to be downloaded and installed in the browser.  Modern browsers will prompt the user when a plug-in is needed and will even automatically access the server where that plug-in can be downloaded.
2. Helper applications are separate, stand-alone programs that perform a task the browser can not. (These are not as prevalent now that browsers come with more built-in facilities.)  Helper applications are typically used when a browser does not support a particular communications protocol.  In this case an application that provides that service can be executed by the browser. For example, telnet access was not built into Netscape Navigator 3.0 so a separate telnet application, available on the same computer, had to be run by the browser.  Usually the user specifies, in the browser preferences, the particular application to be used in a particular situation.
7. Embedded Files: In addition to text, HTML documents can contain links to graphic images, video clips, and sounds. These elements are stored in separate files (not necessarily on the same server as the original HTML file) called MIME (Multipurpose Internet Mail Extensions) files; (See LM V, HYPERMEDIA, MULTIMEDIA ON THE NET; for more information click here.)  When the HTML document is displayed by a browser, the browser shows those elements that it can handle and passes off (to plug-ins or helper applications) those that it can not . There are numerous MIME file formats discussed in LM V, but the most common are:
1. Of the image files GIF (a simple format used for basic pictures) is the most common, but the newer JPEG (a compressed format that stores high quality images in relatively small files) is used for information rich images.
2. MPEG is a motion image format for displaying images and sound.
3. AU and WAV are digital audio file formats for playing sounds.

8. "Push technology" is a way of automatically delivering Web pages to a browser without the user selecting it.  Instead some program, called an  "agent" selects the page, usually based on preferences pre-specified by the user. Push is the opposite of "Pull", the normal Web access, in which users selects a page by actually clicking a hyperlink.  This technology, pioneered by Pointcast Network, blends the Web with TV (which automatically delivers content to the user).  Push was hyped as a way of providing an intelligent software "adviser" (the agent) that would recommend Web pages to the user thus reducing the need to search through an overwhelming number of Web sites to find pages of interest.  However, some consider it an invasion of privacy.
9. Web services are Web based applications, utilizing open standards, that provide resources, such as storage management, Web site hosting, stock market investing, business transactions, integrated fax, e-mail and phone services, etc., to subscribers.  Web servicess will be rented as a hosted service over the Internet instead of purchased on a store shelf. Essentially, the Internet will host all your applications as well as your data.
1. Advantages of Web services include the following:
1. Applications and networks are integrated where the user is connected to an array of computers and services that will interact exchanging and combining all forms of data.
2. Users can interact with applications via multimedia interfaces that will include speech recognition, handwriting recognition, etc.
3. Users will have universal access to their information on the Internet from any device, anytime, anywhere.
4. Application software will be automatically updated making it unecessary to purchase these individually
   
2. The open standards (maintained by the W3C) include HTTP as well as the following:
1. XML (EXtensible Markup Language) is an open standard, from the W3C, for specifying data in terms of tagged text, like HTML. It is used for defining data elements on a Web page and business-to-business documents. However, XML tags define data elements instead of text forms and embedd files; this gives rise to the expression "XML is to data as HTML is to text".   Unlike HTML, XML allows for user-defined tags that specify new kinds of data. This makes it possible for Web pages to function like database records.  Since it is platform independent (computer make or type of operating system are irrelevant), it is becoming the defacto  format for Web services and for transmitting electronic data, replacing EDI.  For more details see XML in LM VI.
2. SOAP (Simple Object Access Protocol) is the Web services protocol for accessing different kinds of objects on a network. It uses XML syntax to facilitate the interaction of network objects that may be written in different computer languages and on different operating systems.  SOAP is similar to, but much simpler than, the more complex CORBA and DCOM distributed object systems.  
3. UDDI (Universal Description, Discovery and Integration) is a universally accessible "catalog" of Web services, similar to the Domain Name System (DNS). The purpose of UDDI is to enable software to use SOAP to automatically discover Web services and integrate them for individual use.  There are several types of catalog pages including
   
1. white pages containing addresses,
   
2. yellow pages containing industry classifications, and
   
3. green pages containing descriptions of services, e.g. the XML version, type of encryption, a Document Type Definition (DTD) of the standard, etc.
4. WSDL (Web Services Description Language) is an XML-based language used to a business's services as well provide online customer access to those services. WSDL is the language used to "program" UDDI.  WSDL was developed from Microsoft's SOAP and IBM's Network Accessible Service Specification Language (NASSL), and it replaces both them programming the business services in the UDDI catalog.
3. Development platforms that natively support these standards include:
1. .NET,  Microsoft's suite of tools and services that implement the company's Web strategy.
2. Sun's Web Services (part of the Java 2 Platform, Enterprise Edition (J2EE))
10. {12/24/07}Uses of Web pages:
1. A blog (a portmanteau of web log) is a website where entries are written in chronological order and commonly displayed in reverse chronological order.  See:
1.  Wikipedia's entry for "blog".
2. (NPR) 10th anniversary of "Blog".
2. A wiki is a type of computer software that allows users to easily create, edit and link web pages.  See Wikipedia's entry for "wiki".
3. A podcast is a digital media file, or a related collection of such files, which is distributed over the Internet using syndication feeds for playback on portable media players and personal computers. See Wikipedia's entry for "podcast".
4. ...
   
11. Interesting Web Sites:
1. Alexa, "The Web Information Company", is a website that provides information on the web traffic to other websites.  See Wikipedia's entry for Alexa.
2. MySpace is a social networking website offering an interactive, user-submitted network of friends, personal profiles, blogs, groups, photos, music, and videos. (From MySpace article on Wikipedia)
3. YouTube, founded in February 2005, is a popular free video sharing Web site which lets users upload, view, and share video clips.  (From YouTube article on Wikipedia)  A former student, Jared Miller,  has an account on YouTube, with a couple of his videos; check it out at: http://www.youtube.com/user/jerrycommahello.  (Let me know if anyone else has such an account - post the URL on the forum, like Jared did.)
4. Facebook, recommended by students in the Computer Club, is a social networking service for high school, college, university, corporate, non-profit, military and geographic
5. ...
   
6. Does anyone know of other Web sites that could be included here?  If so, please suggest them on the class forum.

1. The WWW is the network of Web Servers, accessible by HTTP.
2. WWW Clients Access Internet Resources via URLs.
1. URL (Uniform Resource Locators) are the addressing system of the WWW. This system was developed to allow browsers to access any information currently available on the Net (provided by Gopher and WAIS, in addition to _____(13)); in fact, it was designed to incorporate future developments in Internet technology as well.
1. A URL is the Internet-wide address of any document you can read with a WWW client, i.e. a _________(14). A URL can describe any file on the Internet, even though different files may require different protocols to access them.
2. The URL (1) instructs the client program how to contact the server, (2) tells the server to transfer the designated document to the computer on which the client resides, where (3) the client displays the document. All of these activities require just one action from the user: typing the URL or clicking on a link.
2. A URL can have, at most, five distinct parts.
2. The left-most part of a URL is the URL type or protocol prefix used to access the Internet address. The types recognized by a browser include:
1. http:// which designates HTTP and accesses Web sites.  (This is the browser "default" so if the prefix is not typed, the browser will assume http and automatically insert it in front of the URL.)  https:// designates a Web document on a secure server.
2. ftp:// which designates file transfer protocol used to upload and download files via TCP/IP.
3. telnet:// which designate the telnet protocol used to log on to a remote computer or run applications on a network server.  (rlogin://  and tn3270 are infrequently used alternates to telnet.)
4. wais:// which designates Wide Area Information Server, an infrequently used information service.
5. gopher:// which designates a Gopher server, another information service that is virtually obsolete now.
6. news: which opens the newsreader client associated with the browser and accesses a Usenet newsgroup. snews: opens accesses a newsgroup at a secure news server.
7. mailto: which opens the e-mail client associated with the browser so that e-mail can be read or sent.
8. file:/// which opens a file on the local computer system.
Note that the part after the colon is interpreted according to the access scheme. In general, two slashes after the colon introduce a host name (host:port is also valid, or for FTP user:passwd@host or user@host). The port number is usually omitted and defaults to the standard port for the scheme, e.g. port 80 for HTTP.
3. The domain name of the server (or ______(15) name) on which the Internet document resides. (See section C below.) This ends with a slash, followed by . . .
4. the directory path or sequence of directories (or folders) separated by slashes which precede . . .
5. the file name of the document to be accessed (which is not always required). The file can contain any type of data, but only certain types are interpreted directly by most browsers. These include HTML and images in gif or jpeg format. The file's type is given by a MIME type (See section 1.4.F, above) in the HTTP headers returned by the server, e.g. "text/html", "image/gif", and is usually also indicated by its filename extension. A file whose type is not recognized directly by the browser may be passed to an external "viewer" application, e.g. a sound player.
6. The last (optional) part of the URL may be a query string preceded by "?" or a "fragment identifier" preceded by "#". The later indicates a particular position within the specified document.  You can see an example of a query string, if you access FOLDOC and type in a term to look up (e.g. if you type in "FTP" you will see the query string ?query=FTP&action=Search at the end of the URL displayed in the Location box when the answer appears.)
Only alphanumeric, reserved characters (:/?#"<>%+) used for their reserved purposes and "$", "-", "_", ".", "&", "+" are safe and may be transmitted unneeded. Other characters are encoded as a "%" followed by two hexadecimal digits.

3. The Domain Name System (DNS) is a way of associating arcane IP addresses with more memorable "domain names" used in URLs. The Internet Protocol (the "IP" in TCP/IP) uses Internet address information to access every node (client, server, printer, etc.) on the Internet. Every IP address is a series of four integers separated by periods (called "dots"), for example, 131.118.95.254, the unique address of the FSU gateway (to the UMS network).
3. There are two big problems with IP addresses. (1) It is difficult to remember pure numeric addresses and (2) sometimes these IP addresses change. To solve these problems the DNS was designed to handle the addresses of Internet nodes.
4. The DNS establishes a hierarchy of domains (groups of nodes on the Internet). The domain at the top level of the hierarchy maintains a database of addresses of the subdomains beneath it. Each subdomain has similar responsibilities for their subdomains, and so on. For example, the domain name of one of the administrative computers at FSU is fra00.fsu.umd.edu; the top domain is edu, which stands for _________(16); just below that is umd which stands for _____________(17); below that is the fsu domain; fre is the ________________(18).
5. Top-level domains (TLD) specify the general category of the domain.  Until 1998 TLD names were restricted to:
3. gov for Government agencies
4. edu for Educational institutions
5. org for Organizations (nonprofit)
6. mil for Military
7. com for commercial business
8. net for Network organizations, e.g. carriers, ISPs, etc.
9. country abbreviations e.g. uk for Great Britain,  de for Germany, etc.
The limitations resulting from these restricted categories were removed in 1998 when the Internet Ad Hoc Committee (IAHC) proposed six new top-level domains:
1. store for merchants
2. web for parties emphasizing Web activities
3. arts for arts and cultural-oriented entities
4. rec for recreation/entertainment sources
5. info for information services
6. nom for individuals
6. The easily recognizable domain names and their associated IP addresses are maintained on DNS name servers which also performs the conversion from domain names to actual IP addresses. The DNS at FSU is maintained on a name server with the IP address 131.118.80.1; it has the domain name freris.fsu.umd.edu.
7. When the IP address of a node changes, the database of the DNS name server is updated but the domain name remains the same. Thus one never has to worry about the actual address of an Internet resource or whether it has been changed.
8. The Internet Registry, a part of the Internet Activities Board (IAB), currently maintains the DNS.

1. Hypertext Markup Language (HTML) :
1. HTML is a coding language used to create (i.e. program) hypertext documents for use on the WWW. It looks like old-fashioned typesetting code, where one surrounds a block of ASCII text with codes (tags) that indicate how the text should appear. However, in addition, in HTML one can specify that a block of____(19) or an _____(20) is a link to another location within the document or to another file (including protocols other than _____(21)).
1. HTML is standardized by the International Standards Organization (ISO), but many nonstandard tags are being defined by companies like Netscape which become defacto standards; usually, in time, these become actually standards.
2. The word "Markup" comes from the fact that the tags are used to "mark up" standard text with formatting codes.
3. Web clients (_________(22)) are designed to automatically read HTML documents.
2. HTML is a subset of Standard Generalized Markup Language (SGML), a standard, maintained by ISO, for defining the formatting in a text document. In order to decipher format commands in an SGML document, SGML uses format definitions in a separately-created DTD (Document Type Definition) file. As a result SGML is often called a metalanguage, because it describes another language; in this case, the actual formatting commands that are embedded in the text.

1. HTML tags basically do two things:
1. defines the document, e.g. ______(23) identifies the document as HTML, and _______(24), <head>, and ______(25) specify different parts of the HTML code (program).
2. defines the formats/styles for specific parts of text document.

1. Two new Web languages that improve on HTML by augmenting its facilities are:

1. Extensible Markup Language (XML) is to data what HTML is to text. 
   
2. Dynamic HTML (DHTML) facilitates dynamic presentation of Web content; it provides cascading style sheets (CSS) which are used to inhance Web page format and presentation
Aided by the HTML 4.0 release, these new technologies are overcoming HTML's legacy of too many dead links, slow searches, and static pages on today's Internet. However, for an unknown transition period, browsers will be caught between generations. On the other hand, this lag may be just what the embrionic languages need, giving developers enough time to rethink the way their Web applications should work before a next generation Web becomes available.
1. Virtual Reality Modeling Language (VRML):
1. VRML is a coding language used to instruct computers on how to build 3D geometric objects. Software developers us VRML to build complex 3D worlds from these geometric objects.
1. According to FOLDOC, VRML is draft specification for the design and implementation of a platform-independent language for virtual reality scene description.
2. NOTE that VRML is not a mark-up language, i.e. a set of tags inserted into text in order to format that text; instead it is a language itself so a VRML program is executed in order to display the VRML world on a computer monitor.
2. A VRML program is, itself, an ASCII text file containing VRML language commands and for greater realism, graphics files can be added to this world. Because the virtual world is only an ASCII file, with attached graphics files, it can be downloaded quickly via the Internet.
3. VRML is being designed to compliment HTML. Web developers can attach hot links to HTML so users can click on an object and view additional text or images.

        Since its explosion on the conscious of the public only a few years ago, the Web has grown dramatically in virtually every aspect.  It is still in its infancy so its potential boggles the imagination.  Even in the next year significant improvements are expected in its dynamic content, searching capabilities, speed, etc.  These are explored in the thought provoking article Weaving a Better Web, Byte Magazine, March 1998; the online version may be viewed at http://www.byte.com/art/9803/sec5/art1.htm.  See the informative illustration from that article, reproduced as FIGURE WWW-3.

1.2. GOPHER:

        GOPHER was the first Internet service specifically dedicated to information retrieval. It was developed at the University of Minnesota, whose mascot is the Golden Gopher which led to the play on words "Go-For information on the Internet".  Gopher was originally an extremely popular Internet tool, representing an improved level of ease of use when compared to FTP. However, like WAIS, which came later, it has been almost completely superseded by the World Wide Web.  Gopher now only has utility when using a text based system like the FSU VAX or for locating documents that were created before the Web became so popular. Many of the original Gopher file structures, especially those in universities, still exist and can be accessed through most Web browsers (because they also support the Gopher protocol).  However, most Gopher documents have been or are being converted to Web documents.  Gopher is still used in systems incapable of providing the speed an memory needed for Web browsing, e.g. in developing countries.

1. Gopher is a distributed document search and retrieval system  that is built on a nested, menu-based interface that is designed to access hierarchically-organized files.
1. Gopher is actually a TCP/IPapplication protocol in which  hierarchical file structures are maintained on servers that  themselves are part of the overall information structure.  The hierarchical organization of files facilitates an efficient, top-down searching style.
2. Gopher was the first Internet application to provide a way to bring text files from all over the world to a viewer on the searcher's computer.
3. Although most Gopher browsers and files are text-based, Gopher browsers, notably HyperGopher, were developed that displayed graphic images (GIF and JPEG files) that were included in Gopher file directories.
2. Gopher's original appeal (in comparison to FTP) came from:
1. ease of use
2. relative speed
3. intuitive organization,
4. lack of need for specialized hardware or software to run it, and
5. the fact that it is free.
3. Gopherspace is a term used to describe the aggregate of all the information on the thousands of Gopher servers in the world. This information consists of individual files (abstracts, full-length documents or papers, lists, and other file types) organized as a hierarchy of subject categories that can be limited to one server or span multiple Gopher servers. Gopher text files are plain files that lack the kinds of formatting control and font variation that HTML files have. One can think of Gopherspace as that portion of cyberspace that is accessible through Gopher servers.
4. Most Web browsers include a Gopher client and thus can access a  Gopher server directly from the browser if the Internet address of the server is typed in following the prefix gopher:// The Gopher screens do not look as pretty as Web pages, but they are still highly functional; in fact, function over style is one of the virtues of Gopher.
5. Veronica and Jughead (puns on "Archie" the search tool associated with FTP) are search tools developed for Gopher space.  They are index and retrieval systems which can locate items, using keywords, on most of the Gopher servers on the Internet.
1. Veronica provides keyword searches of the titles of Gopher files.
1. It does not do a full-text search of the contents of the files, it finds files whose titles contain the specified search word(s).
2. Using Veronica will greatly speed up a search for information in Gopher space.  Veronica itself usually contains information about a large number of sites dealing with a specific keyword.  This permits the user to find an Internet resource location that is specific to their interests more quickly than manually searching through a hierarchical file structure.
2. When a Veronica search is completed, the results will be presented as a normal Gopher menu.  The user may browse the discovered resources in this menu, as you would use any other Gopher menu.
3. Veronica can be accessed in a variety of ways, e.g.
1. One can often get to Veronica by going through a normal Gopher client.  One chooses "Veronica" from the menu of some Gopher server and then enters a set of query words or special directives.
2. Veronica can also be accessed by using Telnet to log on to a server that has Veronica.
4. Jughead is similar to Veronica, but has fewer options and indexes fewer Gopher sites.
6. When connected to a Gopher site, the user is provided with an opening menu that leads to a practically unlimited number of submenus (that end in a slash, "/") or files.  This allows one to surf as easily as if scanning an extremely large tables of contents.
1. All menu items are numbered, so to choose a specific item, one either types the item number (It appears at the bottom of the screen.) or use the arrow keys to scroll through the menu selections
2. If there is more than one page of listings, pressing the space bar will bring up the subsequent page.
7. Gopher allows the searcher ot access data without knowing precisely what is being sought.  This is because Gopher navigation is based on an inquiry about a subject and does not depend on one's knowledge of computer addresses or locations.  This makes it relatively easy to use for new Internet users.  Also the links among the gopher sites are more or less invisible to users, allowing them to concentrate on the search itself rather than the mechanics of the search tool.
8. The Gopher Menu at the University of Minnesota is a primary starting place for exploring the world's Gopher information hierarchy.

        WAIS (pronounced "ways") is an Internet information retrieval service that was created in the late 1980's.   However, like GOPHER,  it has been virtually superseded by the Web and is therefore of interest only from a technical and historical aspect only.  WAIS was an improvement on GOPHER, but it was "too little, too late" because with the advent of the Web with its ease of use and multimedia capabilities, WAIS could not compete.

1. WAIS is an Internet service that enables users to search and access different types of information from a single interface.  The information can be in any format (text, graphics, or audio) and can reside anywhere on the Internet.
2. WAIS automatically creates specialized subject databases of related files at multiple server locations.   A directory of servers at one location keeps track of these database servers and makes them accessible for searching by users with WAIS client programs.
1. The WAIS user is provided with  a list of the distributed databases and when a specific database is selected, the client program accesses all the servers on which the database is distributed.
2. WAIS provides an enhanced retrieval mechanism which ranks items according to their relevance to a constructed query.
1. When WAIS reports the results of a search, it ranks the results and delivers a document with the search matches ranked by relevance and with each file presented with a "score" beside it.  A score of 1,000 means that the file contains the phrase exactly as specified.
2. One can use the search results to modify the original search specifications thus making the search more focused and specific.  For example, if the fourth-ranked file is closer to what is wanted that the first-ranked file, it can be added to query parameters, saying, in effect, "Get more like this but including the topic in the fourth-ranked file."
3. The results provide a description of each text that meets the search requirements. The user can then retrieve the full text.
3. Web users can use WAIS by either
1. downloading a WAIS client and a "gateway" to the Web browser or
2. using Telnet to connect to a public WAIS client.
3. using Gopher, or
4. accessing it directly using a dedicated WAIS client.
4. Most Web users will find that the abundance of server files and search engines already available on the Web will make WAIS superfluous. However, librarians, medical researchers, and others may find some specialized information available through WAIS that is not currently available on the Web.
5. For more information on WAIS, download a paper by its creator, Brewster Kahle of the Thinking Machines Corporation. WAIS, like Gopher, will not be considered further in this course, but, if you want to investigate information available in WAIS, download a WAIS client from download.com  download  a gateway program to the WAIS client from WWWAIS

       This Learning Module (IV) presents two resource access services,

1. File Transfer which allows a network user to __________(28) files from another computer or ___________(29) files to another computer and
2. Remote Logon which allows a network user to use another network computer as if directly connected to that computer

2.1. FTP (FILE TRANSFER PROTOCOL) AND ARCHIE:

1. FTP (File Transfer Protocol) is a powerful, but simple, file access protocol that part of the TCP/IP suite of protocols. The job of the Internet’s FTP is downloading (retrieving) files from and uploading (saving) files to remote network servers.
1. All FTP clients (1) connect you to a remote FTP server and (2) assist you in uploading/downloading a file from an accessible directory; if you have access privileges at the site.
2. To use an FTP application, you need to know the file name as well as the Internet address (or URL) of the site where the file is stored.
3. Some older FTP applications have a simple command line interface (for example on our VAX, from the VMS $ prompt), but most modern FTPapplicationsoffer GUIs, e.g. WS-FTP.
4. An FTP application is both more functional and more limited than a Telnet application (See below.). It is more functional in the limited domain of file transfer because some of the functions for exchanging files have been incorporated into the FTP software. Anything done by FTP software can be done during a Telnet session. The FTP software simply incorporates the command language into various menu items or selections, making it easier for individuals without a working knowledge of Unix and Internet protocols to download or upload files.
5. One shortcoming of FTP is that one can not normally transfer files directly from one server to another, e.g. if you wanted to transfer you Web site from one provider to another.  One can alwasy take the long, indirect route of downloading to your local computer and then uploading it to the second server.  However there are alternatives:
1. FXP allows you to transfer file from server to server.  Unfortunately this is often disabled by the server administrator for security purposes.
2. I you have a "shell account", i.e. you can use the operating system of the server, then you can use FTP on the server to transfer you files to another server.  However, this system access on your server is rare, an access that can only be given by the server system administrator.  An alternative would be to ask your system administrator to transfer the files for you.
2. There are two kinds of FTP sites:
1. Anonymous FTP sites are those that have been established for the purpose of archiving files, programs, and utilities that are specifically produced for the benefit of the Internet community as freeware or shareware. These sites allow you to use "anonymous" as your login name, and, either "guest" or your full Internet e-mail address as the password. On many sites all of this is taken care of automatically, e.g. one can download files, via FTP, from Web sites without even realizing you are using FTP.
2. Private FTP sites require account registration and passwords for access.
3. FTP file directories are hierarchical. What you will receive upon login will be a directory listing of the subdirectories and files available. You will need to scroll through these looking for items of interest.
1. Many FTP sites have organized files into general categories, but
2. FTP is not designed to provide anything more elaborate than a file name for your guidance.
4. The classic FTP Client look is a two-pane design, e.g. WS_FTP looks like this:



The pane on the left displays the files on your computer and the pane on the right displays the files on the remote computer.  File transfers are as easy as dragging-and-dropping files from one pane to the other or by highlighting a file and clicking one of the direction arrows located between the panes.  Additional features of the FTP Client include: multiple file transfer; the auto re-get or resuming feature; a queuing utility; the scheduling feature; an FTP find utility; a synchronize utility; and for the advanced user, a scripting utility.

5. The files that are transferred can be of any type, but the most common are text files, application programs, binary code, software updates, various utilities, and any of an assortment of helpful or useful computing aids.
1. You should know whether the file you want to move is an executable program or a text file. If it is an executable program, it frequently needs to be identified as a binary file, as contrasted with an ASCII or text identification appropriate for readable files. The FTP software can sometimes make a judgment about what is appropriate (based on a series of algorithms), but if you can supply the information, the transfer may go more smoothly.
6. Archie (supposedly and abbreviation of "archive"), the most popular search tool associated with FTP, is a file location Tool designed to index all FTP sites. One of the inadequacies of FTP is that you have to know the site at which you can find the file you want to download. Because there are thousands of anonymous FTP sites, it could be impossible to find a specific file if you didn’t know where it was located. Archie addresses this problem by producing a single, comprehensive database of the file names and address where they can be accessed.
1. Archie indexes FTP sites so that the searcher can see what files are available; however, the content of the files can not be viewed as it can with the the protocols _________(30), ___________(31), and __________(32).
2.  An Archie search scans FTP sites and produces a searchable database of the files it finds.  Archie’s job is to query all the registered anonymous FTP sites on the Internet in a standardized manner and to create a composite index of the files located on these sites, arranging them in alphabetical order in the database.  The desired files can then be downloaded via FTP.
3. If you know a file name, Archie can tell you where such a file is located. Archie is a software tool that continuously and systematically scans anonymous FTP sites and builds an index of those sites, making it easier to find specific items.
4. There are several versions of Archie ( the newer ones are more user friendly).
5. Inadequacies of Archie: An Archie search can produce hordes of duplicate file names and it does not sort them by subject like the more modern Web search engines do. Also it does not give you descriptions of the files beyond what the FTP provider offers.
6. Archie has lost significance with the growth of the Web, but FTP is still the vehicle used to move files on the Internet.
7. Virtually all modern Web browsers have FTP built in. In fact, downloading via FTP is so transparent in browsers like Netscape Navigator, that the user may be blissfully unaware that a protocol different than HTTP is being used. However, it is obvious when FTP is being used because the the site URL always begins with "ftp://".
8. FTP has several important uses:
1. It's most popular use is to get freeware or shareware from network servers like download.com.
2. FTP is also commonly used to transfer HTML files, graphics, and associated programs between the creator's computer and the server on which the Web site resides.  (It is this latter use that will be needed while developing the project for COSC 120.)
3. Using FTP, you can also update (delete, rename, move, and copy) files on a server; in fact, in COSC 120 you will use an FTP application (WS-FTP) to manage your  Web site rather than worry about learning UNIX the operating system of the Web server.
4. FTP sites are a popular way of archiving information that is frequently requested and often downloaded.
9. FTP programs with a GUI that can be downloaded from the Web include
1. WS_FTP(http://www.ipswitch.com),
2. CuteFTP (http://www.cuteftp.com),
3. and FTP Explorer (http://www.winsite.com).
10. For more information on FTP see FTP 101 at http://www.ftpplanet.com/ftpresources/basics.htm.

        Remote Logon allows a computer user to access another (multiuser) computer, i.e. to log on to and use that computer as if his/her keyboard and monitor were directly connected to that computer. The user's CPU and operating system are "bypassed" and the user's computer simply becomes a terminal connected to the remote computer. The Telnet protocol provides this service in TCP/IP.

1. Telnet, one of the earliest Internet access tools, is the way you can access another computer on a network.  If you have permission, you can log on as if you were using a terminal of that computer. (Such a computer is frequently called a host computer.)
1. Technically, the word "Telnet" can refer to three different things:
1. a user command, which opens a Telnet application,
2. the actual application (program) itself that one uses to (1) connect to a remote computer, (2) read the directory of files loacated on that remote computer, and (3) run the programs on that computer, and
3. the underlying protocol for accessing remote computers that is part of __________(33).
2. The HTTP protocol allows you to _________(34) files on a remote computer, and the FTP protocol allow you to ___________(35) specific files from a remote computer, but, in neither case, are you actually logged on as a user of that computer. With Telnet, you log on as a regular user with whatever privileges you may have been granted to the specific applications and data on that computer.
2. To use Telnet, you need to know the Internet address of the computer to which you want to establish a connection. If you don’t know its address, but do know its common name, you can sometimes use the name in place of the formal Internet address. Simply type the word telnet followed by the sequence Computer Name.ComputerLocation all in one line with no spaces. For example:
telnet://fre.fsu.umd.edu
The result of this request would be an invitation to log on to FSU's VAX minicomputer where the e-mail accounts of all faculty and students are located. You would be prompted for a userid and  password. If accepted, you would be logged on like any normal user of that computer.
3. Telnet is most likely to be used by program developers and anyone who has a need to use specific applications or data located at a particular host computer.  For technical details including a list of the Requests for Comments documents related to Telnet, see Telnet Protocol
(http://www.metrowerks.com/tcpip/spec/telnet.html).

  In section 2.2.A of Learning Module I, OVERVIEW OF CYBERSPACE, five categories of communication services were defined:

_________(36) services enable individuals to exchange electronic messages

_________ _____ (37) services enable users to subscribe to the mass e-mail transmissions on a specified subject.

_________(38) services (e.g. Usenet ) enable users to read "bulletin board messages" posted by other users

_____(39) services (e.g. IRC and ICQ) facilitate real-time group communication by enabling users to join "chat rooms" where all those logged on participate in public message postings.

_______________(40) facilitate real-time computer-based, multimedia interaction between two or more remote stations; each station can have multiple users.

3.1 E-Mail Services:

1. E-mail (electronic mail) is the exchange of computer-generated messages between individual "e-mail accoounts". There are two basically different kinds of e-mail transmissions:
1. Local e-mail, vial a LAN or corporate MAN, does not access the Internet and thus it is unnecessary to include the Internet address of e-mail server of the receiver.  Only the local address (often this is referred to as an "account") needs to be entered via the local e-mail client.
2. Non-local e-mail is transmitted via a WAN.  By far the most common is the Internet, but it is also possible via BITNET, etc. and, in other countries, other WANs may be used.  In this case the full address of the e-mail server (e.g. ____________________(42) for academic e-mail at FSU) must be added; for Internet servers these are appended after the "@" symbol.
2. E-mail enables Individuals to exchange electronic messages; it is a network facility that provides users with a "mailbox " file, where messages are stored. Correspondence can be directed to specific users (with security) as well as to specified groups. Local mail is sent via the "mailer" program in system software. Non-local e-mail is routed over a               (43) such as the Internet.
3. E-mail includes "Talk" or "Phone" services which facilitate real-time, interactive text transfers (not voice) between two Internet users. However, such programs are now called "chat" or "instant message" applications.  (See section 3.4, below.)
4. SMTP (Simple Mail Transfer Protocol), POP (Post Office Protocol), and IMAP (Internet Message Access Protocol) are e-mail protocols of the TCP/IP suite.  Both POP and IMAP use SMTP for communication between the e-mail client and server, but they make e-mail more user friendly.  POP allows users to download e-mail from a mail server to a PC where it can be read, answered, and stored on a hard disk.  IMAP is even better because it allows you to manipulate your e-mail account on the server.
5. E-mail messages are usually encoded in ASCII text. However, you can also send non-text files, such as graphic images and sound files, as attachments sent in binary streams. E-mail was one of the first uses of the Internet and is still the most popular use. A large percentage of the total traffic over the Internet is e-mail. E-mail can also be exchanged between online service users and in networks other than the Internet, both public and private.
6. E-mail can be distributed to lists of people as well as to individuals; if so refer to this as a "mailing list"; these are discussed, below, in section 3.2. A shared distribution list can be managed by using an e-mail reflector. Some mailing lists allow you to subscribe by sending a request to the mailing list administrator. A mailing list that is administered automatically is called a list server.
7. E-mail is one of the protocols included with the Transport Control Protocol/Internet Protocol (TCP/IP) suite of protocols.
1. A popular protocol for sending e-mail is SMTP and
2. Popular protocols for receiving it is POP3 and IMAP.
8. Both Netscape and Microsoft include an e-mail client within their Web browsers.
9. Selected Links: Popular stand-alone e-mail programs are Qualcomm Communications' Eudora and Connectsoft's E-Mail Connection, a shareware

program.

1. The term "mailing list" has two, associated, meanings:
1. the client-server software that facilitates the sending of mass e-mail to a list of subscribers.
2. the actual list of e-mail addresses identified by a single e-mail address (the address of the list server; see section 3.2.C, below).
2. Mailing lists allow network users to subscribe to the mass e-mailings from a single sender.  Subscribers typically join the mailing list in order receive periodic e-mail distributions on a particular topic.  Subscribers may easily "unsubscribe" by sending a message (typically a blank message) to the mailing list.  Mailing lists have become a popular way for Internet users to keep up with topics they're interested in.
1. There are many thousands of mailing lists to which anyone can subscribe; a list of these may be found here.
2. Many producers and other vendors are now using them as a way to keep in touch with customers.
3. A list server (more properly called a mailing list server) is the software that operates the mailing list, i.e. it handles subscription requests and distributes new messages, newsletters, or other postings to the entire list of subscribers as they occur or are scheduled..  The e-mail address of a Mailing list,  e.g  tonyMailinList@tonyListServer.com., is an alias for a list server.
1. A single list server may host several different mailing lists.
2. Two popular list servers are the commercial LISTSERV and the public domain Majordomo. Lyris is a list server that is free for users maintaining very small mailing lists and scales up in price for those managing thousands of mailing list subscribers; it is available Windows, Solaris, and AIX operating systems.
3. If you want to manage a mailing list without having to maintain a list server, you will have to utilize a mailing list host such asYahoo! Groups.
4. A good introduction to list servers, including how to acquire the software and install it is the article List Server at ServerWatch.
(A mailing list server should not be confused with a mail server, which handles incoming and outgoing e-mail for Internet users.).
4. The basic principles of a mailing list are relatively simple; however, issues of administration, security, volume, and scale introduce complexity.  There are two functionally-different types of mailing lists:
1. Two-way mailing lists are fully functional, allowing messages posted by subscribers to be forwarded to all subscribers.
1. Typically these are simply an e-mail address that is an alias which is expanded by a mail exploder to yield ther e-mail addresses of all subscribers.
2. Some mailing lists are simple "reflectors", redirecting mail sent to them to the list of subscribers.
3. Mailing list may be filtered to to forward meaningful content and eleminate uninformative postings, such as advertising or abuse.  The filtering can be done by the software or by humans, in which case the mailing llist is said to be "moderated".
2. One-way mailing lists are limited to the distribution of messages from the host, i.e. messages from subscribers are not forwarded so the subscriber interacts only with the list server (See the next item.) and not other subscribers.
1. One-way outgoing mailing lists are typically used to deliver announcements, newsletters, advertising, etc.  "Spam" is the lowest form of one-way mailing lists.
2. One-way incoming mailing lists make it possible for subscribers to send information or requests to a server, which then takes appropriate action. For example, problems with software can automatically be e-mailed to the producer.
5. There are several modes of message delivery available in mailing lists:
1. Real-time delivery forwards incomming messages as soon as they arrive at the list server.
2. Digest delivery e-mails a summary or synopsis of messages posted during a specific period of time, e.g.the list server may send only one message per day or per week. This minimizes the number of messages received by the subscriber, but it also limits the subscriber's opportunity to see and reply to time-sensitive messages.
3. Web-based delivery allows messages to be viewed via a browser interface. Other advantages of Web-based delivery include navigable list archives and search facilities.
4. Usenet delivery formats are actually "newsgroups" that list messages as posts to a Usenet news server (See section 3.3.D.), allowing Usenet newsreader applications  to access a mailing list.
Both the Web-based and Usenet  mailing list delivery mechanisms actually overlap with that of forums and newsgroups which require the user to access a server rather than having the server to send messages to the users e-mail address; see section 3.3, below.
6. To subscribe to a Mailing List one usually only needs to send a brief message to the server from which the messages are sent.
1. One way to find out whether there is a mailing list on your particular interest is to link to Vivian Neou's Search the List of Lists at 
http://catalog.com/vivian/interest-group-search.html.
2. Explicit advice on subscribing is give at http://catalog.com/vivian/subscribe-instructions.html
7. To establis your own mailing list, you need to put it on an Internet server. Often your access provider (Internet service provider) will help you set it up and maintain it on the provider's server, usually for a fee. If your provider doesn't offer this service, there are some other providers who will  (see 
http://www.catalog.com/vivian/mailing-list-providers.html
for a list of such providers). Vivian (she's written a book on this subject) also tells you about the process of subscribing (or managing subscribers) to a mailing list.
8. Most e-mail clients have a mass mailing facility that simulates a mailing list. These allow the sender to broadcast e-mail messages to groups specified in an "address book".  However this are not true mailing lists because the sender has to manually insert names into his/her address book whereas a mailing list server automatically add subscribers without any human involvement.
9. Additional Resources:
1. A self proclaimed "Internet's premier Mailing List Directory" is Publicly Accessable Maining Lists accessed at http://paml.net/.
2. CataList, the official catalog of LISTSERV® lists
3. Topica, an access page to public mailing lists.
4. The LLNL List of Lists
5. Webcom maintains a Mailing List resource page.
6. To set up your own personal mailing list try Yahoo's mailing list hosting service called Yahoo! Groups.
10. Practical experience using Mailing Lists is gained in Lab 8.

1. Forums, BBS, and newsgroups are "online message boards" that provide one-to-many communications by allowing user messages to be "posted".  In order to read and reply to these message, a user must access the host server (as opposed to the automatic delivery of e-mail or mailing list postings).  Postings facilitate an information exchange usually regarding a specific topic. These provide the latest news on the topic and a discussion facility for users as well as files for downloading files (software updates, demos, etc.).
2. Forums are typically limited, small-scale online message boards (like the forum for this course.) for individuals or  special-interest groups.  These are usually provided by commercial forum hosts like Network 54.
3.  BBS (bulletin board service). {EXPAND}
   
4. Newsgroups are permanent, large-scale online public message boards.
1. News Services enable users to exchange messages that are classified according to specific categories called newsgroups. A newsgroup is an electronic meeting place where network users can discuss a particular subject. According to FOLDOC, Usenet is "probably the largest decentralized information utility in existence!"
1. They are organized by their subject, where each newsgroup has a name intended to reflect its topic of discussion.
2. With facilities similar to E-mail, they allow users to read and post messages (known as articles or postings) to a bulletin board area.
3. Most public newsgroups are managed by Usenet, a distributed BBS that originated at Duke University in 1979; it now includes almost all public newsgroups.
4. Unlike e-mail messages between individuals, newsgroup messages are passed from one system to another.
5. Unlike mailing lists, newsgroup transmissions are not automatic; they must be requested by the user via local client software.
2. Actually a newsgroup is a discussion about a particular subject consisting of notes written to a central host and redistributed (on the Internet) through Usenet, a worldwide network of news discussion groups. Usenet uses the Network News Transfer Protocol (NNTP) part of the  _________() protocol suite.
3. Newsgroups are organized into subject hierarchies, with the first few letters of the newsgroup name indicating the major subject category and sub-categories represented by a subtopic name. Many subjects have multiple levels of subtopics. Some major subject categories are: news, rec (recreation), soc (society), sci (science), comp (computers), and so forth (there are many more). Users can post to existing newsgroups, respond to previous posts, and create new newsgroups.
4. Newcomers to