Internet Basics: A Detailed Introduction

History / Background / Future

The Internet is a worldwide network of networks. It is composed of thousands of separately administered networks of different sizes and types. The Internet began decades ago as a military / industrial / governmental network. Over the years the NSFNet became the primary network on the Internet, and merged with other networks such as the educational network BITNet. Today the Internet is largely composed of educational and governmental institutions but the number of private providers and organizations on the Internet is increasing drastically. The Internet is the foundation for the Information Superhighway, and is being affected every day by legislation and by mergers and initiatives within the telecommunications industry. 

Based on two principal protocols, Transmission Control Protocol and Internet Protocol (TCP/IP), the Internet fundamentally allows three basic functions: 
 

1. electronic mail (e-mail) 
2. remote logon (telnet) 
3. file transfer (FTP) 

All of the information you can access on the Internet is stored and accessed by the client-server model. This just means that information is stored in one place -- the server -- and machines that access the information are called clients. The Client / Server paradigm has transformed the way information is accessed. Many of the Internet functions (such as telnet, FTP, gopher, and Web browsers) are available as individual software packages, or clients, which are installed on an individual machine (a PC, Sun, or mainframe). The clients can be personalized by the user to determine how information accessed on a server is viewed. Information located on a server can usually be accessed by a variety of different clients. 

Basic Internet Functions

 

E-mail 

E-mail allows us to communicate with colleagues through mail messages delivered on the Internet. E-mail also allows us to communicate using topical electronic conferences such as listserves and Usenet news-groups. In listserves, messages mailed to the list are distributed to all the list subscribers via e-mail. Usenet is a collection of thousands of bulletin board style systems, where messages are posted to a group and archived. You can use a news reader, such as NetNews, to read messages posted to a particular news-group. There are many different e-mail clients so the look and feel of e-mail systems differs greatly from system to system. (A more detailed explanation of email, listserves, UseNet, etc., is available online.) 

Telnet: 

Telnet allows you to remotely log in to another computer system. For instance, if you were using a PC connected to the Internet, anywhere in the world, you could type "telnet uicvm.uic.edu" (or "tn3270 uicvm.uic.edu") and see the flame screen. Cautions: 1. When you telnet from your local system to another computer system, you must have an account and password on that system, or that system must be set up to accommodate public access. 2. When you are connected to a remote system, you are using the commands for that system, not for your local system. When you first login to a remote system, you will usually see a message telling you how to quit. Take notes! (A more detailed explanation of telnet is available online.) 

FTP: 

The File Transfer Protocol allows retrieval of all kinds of files from other computer systems. These documents can include programs, text documents, and a variety of media files (sound, video, graphics). Many sites set up anonymous ftp servers, which can be accessed by logging in as anonymous and using your own userid as your password. Three things to keep in mind when FTPing documents: 1. Remote systems are usually case-sensitive. 2. Files you retrieve may not be ASCII text documents, in which case you will need to switch to binary mode before transferring the document. 3. Documents will often be compressed for faster transfer and will need to be decompressed to be used. (Most common compression / decompression programs are in the public domain.) (A more detailed explanation of FTP is available online.) 

Advanced Internet Services

 

Gopher: 

Gopher is a menu-based interface to the Internet. Developed at the University of Minnesota, most gophers allow retrieval of text documents, database searches, telnets to other systems, and connection to other gopher menus. To start gopher from UIC's CMS, type gopher . (A more detailed explanation of gopher is available online.) 

VERONICA: 

The Very Easy Rodent-Oriented Networked Information and Computer Archives (VERONICA) program allows subject searching of gopher-space. VERONICA was developed at the University of Nevada at Las Vegas. To access VERONICA from UIC's gopher, type gopher and then choose THE RESEARCHER. 

Archie: 

Archie is an index of files available through anonymous FTP. To search an archie from CMS type telnet archie.rutgers.edu ; telnet archie.unl.edu ; telnet archie.ans.net ; or telnet quiche.cs.mcgill.ca . You generally logon as archie. Use the command set maxhits 5 to limit the number of retrievals you get. The command prog your term will search the index for your term. 

WAIS: 

Wide Area Information Service (WAIS) allows full-text searching of texts. It uses the Z39.50 query protocol to communicate between clients and servers. A WAIS search engine can be used to access one particular source or to search a variety of sources. WAIS does not use Boolean operators as most systems do but instead relies on relevancy feedback. There are WAIS clients available for the PC, Mac, Unix and VMS systems. To try a WAIS search engine at UIC, connect to Britannica Online using a Web client; or from CMS, type telnet quake.think.com and login as wais (lower-case). 

World Wide Web: 

The World Wide Web (WWW) was developed by CERN, a particle physics organization. WWW client browsers such as Mosaic, Cello, Lynx, and NetScape allow access to hypertext documents. With most browsers other than Lynx, you can individualize them to play sound, graphics, or video. The WWW is based on the HyperText Transfer Protocol (HTTP) and the Uniform Resource Locator (URL). To try a WWW browser at UIC, use Mosaic or NetScape from an LHS-C PC or Macintosh. (A more detailed explanation (by W3C) of the Web is available online.) 

Web Indexes: 

Just like Gophers are indexed by VERONICA servers, the WorldWideWeb is indexed by a variety of tools such as Yahoo, Lycos, and Altavista. Most Web indexes cover only the World Wide Web. To try a Web index, use a Web browser, connect to the URL http://www.uic.edu/search.html , and select an index.