[Next] [Previous] [Top]

Internet Connection and Access

Getting connected

• A direct connection to the Interent
  • This method uses a dedicated machine (a gateway) to connect into the Internet backbone

• Connecting through someone else's gateway

• Using a direct service provider
  • Your machine accesses a company's gateway that provides limited or full access to Internet services.

• Using an indirect service provider
  • Most used access method, although not all service providers offer all the Internet features you may want to access.

Connection Medium

• Connecting through a Command-Line Account

• Connecting through a Menu-based Account

• Connecting through a GUI Account

Locating &Retrieving

• Early Ways of storing Info on the net
  • FTP access to Info

• Improvements on Early Methods
  • Archie database

  • Gopher Access to ftp sites

• New methods for storing Info
  • WAIS database of Documents

  • WWW documents

Using Applications on the Internet

File Transfer Protocol

• FTP allows the user to establish connections with other computers on the Internet

• The FTP is an example of a client-server system

• One common type of ftp server is an anonymous FTP server

• Large amount of (free) software available on anonymous FTP servers

• Originally, FTP was developed to be used from a command-line prompt

• The s/w available from your internet server determines FTP connection method

• ftp allows you to directly transfer both text and binary (program, graphics, and so on) files

• A number of Window-based FTP clients are now available e.g WS_FTP

• Disadvantage - can be difficult to find information.
  • Tip: always download the README or INDEX files and read the contents - the files are put there for a reason!

  • Queries should be addressed to postmaster of ftp site

• FTP Etiquette
  • It is highly recommended that FTP sessions be held only after normal business hours for that site, preferably late at night.

  • Think in terms of the current time at the site that's being visited

Archie

• Archie - was the first of the info retrieval systems

• Purpose - to create a central index of files

• Lets you search for file names stored at public Archie

• Archie server returns to you the machine name and location of files that match the string you are searching for

• Limitations:
  • Need to know something about the name of the file

  • Not all sites have anonymous FTP servers participate in Archie database sites

Gopher

• Gopher is another information distribution service

• The protocol and software allow you to browse info systems

• Gopher is primarily designed as a document retrieval system

• Gopher presents info in a clear structured hierarchical list

• Gopher can connect you to other Internet services

• Displaying or downloading a file is as easy as selecting an item from a menu

• All Gopher servers are at some point interconnected-this network of Gopher servers is known as Gopherspace

• Veronica - veronica is used to do a search through Gopherspace for file titles

• Advantages -
  • Can include menu items on a server that, when selected, move the user to other Gopher servers on the internet

  • Ease of use

WAIS

• WAIS - Wide Area Info Server

• Good for finding all documents available on a particular subject

• Searches servers all over the world

• WAIS searches a set of databases that has been indexed with keywords

• Returns addresses where you can locate documents of interest

• Key features:-
  • Ability of a WAIS server to have indexes that actually point to other WAIS servers

Telnet

• Used to connect two computers together

• It provides a terminal connection to the remote machine - command line access
  • i.e lets you log into a remote computer directly through the Internet

• With Telnet what you see really depends on what the host resource provides

• Can access resources quickly

• Telnet - not a search medium, more a retrieval medium

• Telnet is transparent