Network Navigation Tools
Overview
Archie
Gopher
Veronica
Jughead
WWW
WAIS

Objective:

* To provide an overview of the nevigation tools

Organisation of this module

For each tool the following items are discussed:
* Whar is it?
* How it works?
* How to access it?
* Search commands used

Overview

  • What is a Client-Server program ?
  • How Client-Server program works ?
  • The Client program is responsible for :
  • Server is responsible for :
  • Advantages of Client-Server metaphor :
  • The Client provides :
  • The Server provides :
  • Where the Clients are :
  • Ways to locate Client-Server related information :
  • Why you do (or don't) want to use a local Client :
  • Accessing local and remote clients and server :
  • Some special internet connections :

  • What is a Client-Server program ?

    * The Client computer is connected via a network to the server computer. The server stores and manages the data; the client answers, updates, processes and formats the data; the network provides conduit between the two.

    * The Client-Server computing provides the sharing of work between the server computer which acts as backend and the client computer which acts as front end and allows each to perform the function it does best.

    * Client computer could be PCs (DOS, Windows), Mac, workstations, mini or mainframe computer.


  • How Client-Server program works ?
  • * Servers usually operate on multi-user OS machines such as UNIX, VMS
  • * Both Client and Server are set of programs.

    * The user never interacts directly with a server program.

    * The Client programs are the ones to which the user gives commands. The Client program inturn interacts with one or more server programs.

    * A server consists of special software which accepts requests (or queries or commands) and sends a response automatically.

    * The client and server programs exchange messages using a protocol created or selected by the program's developers.


  • The Client program is responsible for :
  • * Providing the user interface

    * Converting the user commands to messages understood by the server

    * Opening and maintaining connection(s) to the appropriate server programs

    * Passing user's command to the server.

    * Receiving messages and information from the server and displaying the appropriate output on front end, saving files within user's account.


  • Server is responsible for :
  • * Responding to the Client's requests properly


  • Advantages of Client-Server metaphor :
  • * Client programs reduce the load on a computer that is providing an Internet service

    * It helps in cost cutdown on hardware


  • The Client provides :
  • * An individualised environment

    * Flexibility

    * Increase in efficiency

    * Intelligent functions


  • The Server provides :
  • * Advanced operating system features

    * Multiuser environment

    * Centralised data management and information sharing environment

    * High level administration and security


  • Where the Clients are :
  • * Local Client: the one which is installed on your system

    * Proxy Client: the one on another system which you access through the Internet


  • Ways to locate Client-Server related information :
  • * Checking for appropriate FAQ (frequently asked questions and their answers) documents

    * Reading articles in the corresponding usenet news groups

    * Doing an archie search


  • Why you do (or don't) want to use a local Client :
  • * Familiar user interface which takes full advantage of your system's capabilities

    * Work locally with your files

    * Be sparing of network resources

    * Try a public-access version of the client and obtain a local client if it suits you.


  • Accessing local and remote clients and server :
  • * To use a local client, try the client name

    Ex:

    telnet
    gopher
    archie

    * To reach a remote client, use the remote login (telnet) facility.

    Ex:

    telnet internic.net (no login reqd)
    telnet gopher.internic.net (login as gopher)
    telnet quake.think.com (sorry! not working)
    telnet archie.sura.net (no login reqd)

    * To reach a server, use the appropriate client.

    Ex:

    ftp ftp.uu.net
    gopher internic.net
    gopher gopher.internic.net

  • Some special internet connections :
  • * anonymous ftp to csd4.csd.uwm.edu in /pub/inet.services.txt

    * gopher or email to bbslist@aug3.augsburg.edu


    What is Archie?

    * Conceived and created at McGill University, Canada

    * A Client-Server information system for searching the contents of anonymous ftp archives.

    * Archie also offers WHATIS database, which provides a brief synopsis for some 4000 items in public archives.

    How Archie works?

    * Uses the connnectionless protocol UDP (User Datagram Protocol), specified in Postel (1980).

    * Currently Archie automatically keeps track of the name directories and files of anonymous ftp sites world-wide. These files include software, Electronic texts, journals, newsletters, among other things.

    * The query langauge allows fuzzy pattern matching for complex expressions such as sub-string matching, upper/lower case,wildcard characters. Users are also able to state a level of priority for the processing of the query. This is known as niceness level.


    How Archie Works

    * Archie conducts two types of searches.

    *Name Search:

    It will search for files containing a certain set of characters in its filename

    Ex:

    To do a filename search for the word "elm" on Archie via telnet:

    How to Access Archie?

    * Through Local Client: Both command driven and window based clients are availble. It is available through anonymous ftp from nic.funet.fi in
    /pub/archive/comp.sources.amiga/volume89/util/archie18.l.z

    * Through proxy client: A command-driven interface for Archie is available by interactive telnet login; login as archie.

    Eg:

    telnet archie.rudgers.edu
    telnet archie.sura.net
    telnet archie.funet.fi
    telnet archie.au

    * Archie is also reachable by e-mail; you can email your queries to archie@'server' where server is one of the servers mentioned for telnet access, with body of the mail being an archie command.


    Search Commonds for Archie

    Search commonds for accessing archie server

    * show search to see the search parameters

    * set search exact to do exact string match of the file name

    * set search sub to do substring search of the file name but the case is ignored

    * set search subcase to do substring search considering the case of the substring

    * set match_path path-list to do a search on specific directories

    * set match_domain domain-list to do a geographic search

    * find is synonym for prog command

    * bugs lists bugs in the Archie system

    * help lists help commands available for Archie system

    * mail destination sends the result to the email address given.


    Search commonds for accessing archie cleint
    

    %archie -modifiers expression

    where modifiers are:
    -c returns file names containing the string name considering the case also -e searches for exact file name match -m number limits the search to the number specified -h name searches only the servers specified in name

    Search commonds for accessing archie through email
    

    path email address email addresss to which search result to be sent

    compress the output is sent in compressed form

    prog expression looks for file name that matches the expression

    help help file for mail archie

    whatis keyword returns list of files that match the keyword in
    whatis database.

    What is Gopher?

    * Developed in 1991 at the University of Minnesota. Its protocol is documented in RFC 1436 and uses client-server architecture.

    * Gopher servers can identify documents of different types, and typically store general information about their sites, links to other servers and services elsewhere and documents such as books, electronic journals and articles.

    * It is a finding aid to resources on Internet that lets you prowl through by selecting resources from menus, without having to worry about domain names, IP addresses, changing programs.

    * Each gopher follows the same menu mechanisms. Many contain unique collection of Internet resources, but menus may be organized differently. Choose the gopher system that best suits your needs.

    * The system enforces licensing restrictions wherever it is applicable

    How Gopher works

    * Gopher servers can interface with WAIS and WWW. The interface is achieved by means of software gateways, which map one protocol into another. Gopher is developed to allow clients to use different services and speak different protocols as the need may arise (e.g. finger, x.500 directory service).

    * Search types on Gopher:

    an index search of a particular database
    an index search of the whole Gopher community (VERONICA)
    an index search of a Gopher server or top menu of some Gopher servers (jughead)

    Each gopher contains a variety of resources. To find the gopher that you want use VERONICA, a gopher menu searching program


    How to access to Gopher?

    * Through local Client:

    Recent releases of gopher software are available via anonymous ftp from boombox.micro.umn.edu (/pub/gopher) and most large sites. This provides additional functionality, such as viewing images, downloading, and creating bookmarks.

    Ex:

    Geographic access to Gophers is provided at gopher.virginia.edu University of Virginia Gopher Worldwide Internet Services Other Gopher and Information Services Internet accessible library catalogues

    Subject tree access to Gophers is provided at

    gopher.msu.edu Michigan State University Gopher Network & Database Resources Internet Resources by Subject

    Library catalogs are listed by Yale University

    Gopher: yaleinfo.yale.edu Yale University Gopher Browse Yaleinfo (Yale & Internet Information) Library Catalogs World-Wide

    * Through proxy Client:

    You can telnet to a system that has a gopher client. With this method there is usually a limited number of logons allowed, and most Gophers do not allow this type of direct telnet access.

    Ex:

    telnet marvel.loc.gov and login as marvel Alternatively, telnet to a remote computer where you have an account and if that system has a gopher client, you can connect directly to a Gopher by address.
    Ex: gopher arl.cni.org


    How to access Gopher?

    Some public access telnet sites are:

    ------------------------------------------------------------------------------------------- Public Gopher access sites Login Location -------------------------------------------------------------------------------------------- consultant.micro.umn.edu gopher North America uxl.cso.uiuc.edu gopher North America panda.uiowa.edu panda North America gopher.msu.edu gopher North America gopher.ebone.net gopher Europe info.anu.edu.au info Australia gopher.chalmers.se gopher Sweden tolten.pub.cl gopher South America ecnet.ec gopher Ecuador gan.ncc.go.jp gopher Japan

    * Through Email:If you do not have access to Internet you can send mails to gophermail sites and get information through email.

    Ex:

    gophermail@calvin.edu
    gophermail@eunet.cz

    The gopher menus are mailed back when you send a mail to this address. Then select the menu which you want and preceed this number with X and send back the mail to the gopher address.

    Some public access telnet sites are:

    ------------------------------------------------------------------------------------------- Public Gopher access sites Login Location -------------------------------------------------------------------------------------------- consultant.micro.umn.edu gopher North America uxl.cso.uiuc.edu gopher North America panda.uiowa.edu panda North America gopher.msu.edu gopher North America gopher.ebone.net gopher Europe info.anu.edu.au info Australia gopher.chalmers.se gopher Sweden tolten.pub.cl gopher South America ecnet.ec gopher Ecuador gan.ncc.go.jp gopher Japan

    * Through Email:If you do not have access to Internet you can send mails to gophermail sites and get information through email.

    Ex:

    gophermail@calvin.edu
    gophermail@eunet.cz

    The gopher menus are mailed back when you send a mail to this address. Then select the menu which you want and preceed this number with X and send back the mail to the gopher address.

    Some hints to do a Gopher search:

    * Gopher searches are always case-insensitive

    * When you approach a new index, keep the search simple

    * Try to use multiple keywords, boolean operators which the Gopher index allows on a frequently used gopher server

    * Different resources from the same gopher server usually remain the same.

    * There is no obvious way of cancelling a search once it is satarted. ^C terminates the Gopher client.


    
    

    Search Options for Gopher:

    * Gopher menus provide a list of options from which to choose. These options can lead to another menu, a database, a document or make a Telnet connection to yet another computer.

    * After each gopher menu option is a special symbol which indicates the type of information available. The major symbols are:

    / leads to another menu . (or blank) leads to a document ? searchable index (tel) makes a telnet connection to another computer


    * Some common commands used in gopher search:

    m: go to main menu u: go up a menu ?: for help /: directory search q: exit b: go back a screen space bar: go forward a screen


    What is Verinica?

  • Veronica (Very Easy Rodent-Oriented Net-wide Index to Computerised Archives) is an easy-to-use keywork search utility for gopher. Veronica is for gopher as Archie is for ftp and was developed at University of Neveda at Reno.

  • Veronica search produces a list of gopher items, each of which is a direct point to a gopher data source. It operates in gopher and provides keyword searching of titles of gopher items.

  • To access VERONICA, look around for any gopher server with a menu item like: 15. Search titles in Gopherspace using Veronica'

  • Online help files for VERONICA are available.
    e.g:
    "How to compose VERONICA queries and "FAQ: Frequently Asked Questions about VERONICA".

  • To conduct a VERONICA search, select any of the "Search gopher Directory Titles. Your results will be more manageable than searches using "Search gopherspace (veronica)..."

  • Boolean operators AND/OR/NOT and truncation (*) can be used in Veronica searches.
  • The search on the gopher space can be limited by using type specifiers preceded by -t at the end of the search terms.

    The following are some type specifiers:

    0: item is a file

    1: item is a directory

    3: ERROR

    4: item is a BinHexed Mac file (discouraged)

    5: item is a DOS binary archive of some kind (discouraged)

    6: item is a Unix u;nencoded file (discouraged)

    7: itemis an Index-Search server

    8: item is a pointer to a Telnet session

    9: item is a binary file of some sort

    +: redundant server (same as previous server)

    Ex:

    Words to search for: aids -t18
    This will limit your retrieval to a menu of Gopher
    DIRECTORIES or TELNET links whose names contain the word "aids"

    Ex:

    gopher gopher.unr.edu
    University of Nevada, Reno Gopher
    Search All of Gopherspace using Veronica
    Experimental Veronica Query Interface: Chooses Server for You!
    Veronica: Search ALL Gopherspace by specifying word(s) in Titles

    * Jughead developed at the University of Utah, is a software program which allows for searching in Gopher menus.


    What is Jughead?

    * Jughead is diferent from Veronica in that Jughead typically limits searches to the menus of a local on-site Gopher or to the top few levels of Gopher menus around the world.

    Ex:

    gopher marvel.loc.gov
    Library of Congress MARVEL Menus
    Search LC MARVEL Menus
    Search LC MARVEL Menus Using Jughead

    Example of a Jughead server which searches Gopher menus all over the world is

    Washington and Lee University Gopher
    Finding Gopher resources
    Search High-Level Gopher Menus by JUGHEAD a W&L

    What is WWW ?

    * The World Wide Web (or Web) is a client-server distributed hypermedia system initially developed at CERN (European Laboratory for Particle Physics in Switzerland), where it was envisaged as a means of sharing information between physicists.

    * The Web client program is a browser which allows the user to navigate through links across documents stored in different parts of the globe, save documents locally, make personal annotations and create page markers, among other things.

    * The navigation on the network is done through hyper links. The client program is a single, easy to use interface to almost everything there is in the Internet. It is supported by a suite of programs that understand different protocols and handle the various files and data compression formats automatically.


    How WWW works?

    * A Web server keeps Web page. A Web Server is a computer that runs a Hypertext Transfer Protocol (HTTP) program as a background task. HTTP is much like any other FTP, except that it has a few modifications that make it more suitable to Web applications than FTP.

    * The HTTP program collects the incoming requests from the Web browsers on the network. The server sends the requested page to the client. Servers can range in size from mainframes to network-connected desktop PCs, serving needs ranging from institutional to individual.

    * The Web pages on a server are text files to which codes have been added in Hypertext Markup Language (HTML). These codes are interpreted by the Web browser that receives them, and are translated into fonts, margins, indentations and other formatting features.

    * HTML tags may also specify the names and locations of other files, such as plain text, GIF-format graphics, AU- format audio and MPEG-format video. They can specify links to other Web pages, email services, Usenet newsgroup access, login authorization and a variety of fill-in-the blank applications, such as order froms, surveys and elecctronic "guest registers"

    * It is a simple way of describing almost any information resource, specifying a standard format for locating information on the net as: ://:/

    * This identifies the protocol to be used to access the information, the site on which it is located, the IP port number to connect to, as well as protocol specific information.

    Ex:

    news:soc.culture.indian (for USENET groups)
    mailto:kta@ncsi.iisc.ernet.in (for email)
    ftp://ftp.eff.org/docs/policy (for ftp)
    gopher://ftp.eff.org/docs/policy (for gopher)
    http://www.whitehouse.gov/index.html (for WWW)
    telnet://telnet.w3.org

    How to access to WWW?

    Through text-based software:

    * The WWW can be viewed through a text-based software package called Lynx.

    * Lynx can be intalled on a local server, and is available through anonymous ftp from ftp2.cc.ukans.edu in /pub/lynx

    * Lynx can be accessed through telnet at a few public sites:

    ukanaix.cc.ukans.edu (login as "www")
    vienna.hh.lib.umich.edu (login as "lynx")
    info.cern.ch (login not required)

    Through special browsers

    * WWW is best accessed via special client software, such as MOSAIC, CELLO, NETSCAPE. These browsers allow you to view WWW pages in full graphic/multimedia format.

    * Mosaic is available through anonymous ftp from ftp.ncsa.uiuc.edu

    * Netscape is available through anonymous ftp from

    http://home.mcom.com/info/how-to-get-it.html

    * Cello is available through anonymous ftp from

    ftp.law.cornell.edu/pub/LII/Cello/cello.zip

    Through Email browsers

    * Agora is an email browser for WWW

    * Send a mail to agora@mail.w3.org with body of the text as

    SEND 'URL address'

    * Do a http://www.cern.ch/ as a starting point to WWW and to know more about it.

    * A huge and diverse list of resources is available at:

    http://www.clark.net/pub/journalism/awesome.html

    * NCSA's Meta-Index is available at:

    http://www.ncsa.uiuc.edu/SDG/Software/Mosaic/MetaIndex.html

    * The whole Internet catalog is available at:

    http://nearnet.gnn.com/wic/newrescat.toc.html

    Fun places on the Internet:

    *Do ahttp://www.cm.cf.ac.uk/Movies to browse Cardiff's Movie Database
    *Do http://www.ugcs.caltech.edu/ to view Star Tech : The Next Generation
    *Do http://www.imfi.net/cool.html to browse the cool sites of the day
    *Do http://www.math.ufl.edu/`mitgardt/rsfc/html to browse College Football www site

  • For text-based browers
  • Search options for WWW

    for text based brwosers

    commands function -------------------------------------------- up arrow previous highlight right arrow follow the link left arrow previous link space bar next screen m main menu enter,return follow the link h,? help about Lynx q quit Lynx p different ways of obtaining a copy of the file a add a bookmark v see the list of bookmarks d delete a bookmark g go to specified URL / search a string of chrs within the current doc = show URL and other inf about current doc delete show docs visited in the current session


    
    

    Search options for WWW

  • For special browers
  • Netscape gives the following top level menu:

    ----------------------------------------------------------------------------------------------------- FILE EDIT VIEW GO BOOKMARKS OPTIONS DIRECTORY ----------------------------------------------------------------------------------------------------- BACK FORWARD HOME RELOAD IMAGES OPEN FIND STOP -----------------------------------------------------------------------------------------------------

  • For E-mail based browers
  • * When a mail is sent to the browser, it sends back the corresponding web page with details of other linked URL sites


    What is WAIS?

    * Wide Area Information Servers was developed as an experimental venture to explore text-based information systems for corporate executives. The participants were Thinking Machines Corporation, Apple Computer, Dow Jones & Co., and KPMG Peat Marwick.

    * WAIS is a client-server distributed document retrieval system. The WAIS server system implements weighted term document retrieval with relevance feedback. The WAIS client program provides the interface for the user to formulate and handle a query.

    * WAIS is based on Z39.50 (ANSI standard for requesting bibliographic information: 'Information Retrieval Definition and Protocol specification for Library Applicatons) that describes a way for one computer to ask another to do searches for it.


    How to access WAIS?

    * Once you are connected to wais, select the references to over
    500 databases from Directory of Servers.

    * Each word in a record is indexed and search process is broadly
    based on vector space model

    * Select a set of databases to be searched

    * Formulate query in natural langauge

    * WAIS displays information about each selected database as it processes the query based on some relevance method

    * Titles of retrieved documents are displayed. Complete record of the selected titles can be viewed

    * The search can be reinitiated either by modifying the query or by relevance feedback analysis of selected set of documents

    * Through Local Client:

    There are many freely available clients for various operating systems. The Thinking Machines release of WAIS is available via anonymous ftp from ftp.uu.net in the directory /networking/info-service/WAIS as WAIS- 8.b5.1.tar.Z. The CNIDR release of free WAIS is available via anonymous ftp from ftp.cnidr.org in the directory /pub/NIDR.tools/ as free-WAIS-0.2.tar

    Both textbased (swais) and graphical (xwais) clients are available.

    * Through proxy Client:

    Wais can be accessed through telnet to:

    quake.think.com (login: wais) (not available now)
    sunsite.unc.edu (login: swais)

    * Through E-mail:

    WAIS was accessible through Email at
    WAISmail@quake.think.com

    * Through Gopher and Web:

    Most Gopher services have an options. In Gopher menu select
    Other Gopher and Information Services/
    WAIS based information

    On web do http://www.wais.com

    SWAIS commands

    ------------------------------------------------------------------------ commands function ------------------------------------------------------------------------ j, down arrow move down one source k, up arrow move up one source j, ^V , ^D move down one screen K, 'esc' v,^U move up one screen ### position to source number ## / search for source space select current source = deselect all sources v, 'comma' view current source info return perform search s select new sources (refresh source list) w select new keywords X, - remove current source o show SWAIS options h, ? show help facility H display program history q leave this program

    PCWAIS displays the fallowing options

    --------------------------------------------- FILE EDIT QUESTION SOURCES WINDOW ---------------------------------------------