From: scott@sklib.usask.ca
Subject: The NISSWAIS Project
Organization: University of Saskatchewan
Date: Tue, 28 Jul 1992 12:25:06 GMT

I found this on the NISS Bulletin Board (UK):

                         The NISSWAIS PROJECT


     WAIS - An Overview

     A Wide Area Information Server (WAIS) system is a suite of
     software that enables the distribution of textual
     information over electronic networks (Electronic
     Publishing), and allows a user to search and retrieve
     multi-media information from databases anywhere in the
     world.  WAIS was originally developed by Thinking Machines
     Corporation in collaboration with others, and is now
     available on most of the popular hardware platforms.  Using
     the interface of your choice, WAIS enables you to find
     personal, corporate and public information.  Information is
     accessible regardless of format, text formatted documents,
     pictures, spreadsheets, graphics, sound or video, but
     currently most of the available databases are full text.

     WAIS recognises natural language queries.  The search and
     retrieval of relevant information is made using your native
     language.  The most relevant documents regardless of size,
     can be sent back to the server in their entirety to further
     refine your search i.e. telling the server to "find me more
     like this document".  Proven searches can then be
     automatically repeated, monitoring and alerting you to new
     information as it becomes available.  WAIS uses a single
     computer to computer protocol (NISO Z39.50). Each WAIS
     server reads your question and based on its words, searches
     the full text of the database for the most relevant
     documents and ranks them using automatic word weighting.
     Servers need not fully understand your query as the
     retrieval process is based on a search method called
     relevance feedback.  Thinking Machines provide an
     implementation of Z39.50 to help developers to build
     interfaces and servers.

     Z39.50 is an American National Standard that was approved
     in 1988 by the National Information Standards Organisation
     (NISO) and the American National Standards Institute (ANSI)
     the accredited standards writing body that serves the
     library, information and publishing communities.  Version 2
     of Z39.50 (Z39.50-1992) has been approved within NISO and
     forwarded to ANSI for formal approval as an American
     National Standard.  Z39.50 is an applications layer
     protocol within the OSI reference model developed by the
     International Standards Organisation (ISO).  It's purpose
     is to allow one computer operating in a client mode to
     perform information retrieval queries against another
     computer acting as an information server.

     The NISO Z39.50 protocol provides functions which permit
     the client system to query a database server and obtain
     records from this server.  The protocol includes the
     following operations:

     a) A client can transmit a query to the server for
        evaluation.  The server can return a report of the
        number of records satisfying the query, or an error
        report.

     b) A client can request the transmission of a result set
        created by the query from server to client.  This can be
        done all at once, record by record, or by sending a
        client specified group of records.  A client also has the
        option of requesting a conditional transfer of records
        from the server as part of the search process based on
        the size of the search result.

     c) A server can notify the client that a search will take a
        large amount of computing resource on the client and/or
        will produce a very large result, optionally suspend the
        search and request confirmation from the client.

     d) The server can send security challenges to the client as
        part of the search process; the client must respond to
        these challenges.

     The Z39.50 protocol is message oriented in the sense that
     the client transmits a structured unit of data (an
     application protocol data unit, or APDU) to the server to
     initiate a request, and receives a similar APDU in response.
     It is interactively oriented in the sense that execution of
     a search (including resource control interactions) or the
     transfer of a result set to a client may involve repeated
     interactions between client and server.

     The standard provides a uniform procedure for client
     computers to query information resources such as server
     computers supporting on-line library catalogues.  For
     example, the development of the client program running on
     one machine may provide end users with a common means of
     access to a variety of information resources attached to a
     computer network.  While many of the initial applications
     of Z39.50 are for use with bibliographic data (on-line
     public access library catalogues for example), the protocol
     is actually quite general and search "attribute sets" can be
     defined which allow the protocol to work with most other
     types of data.  Some specialised data such as images may
     necessitate protocol extensions.  Various groups are
     currently exploring the area of protocol extensions and are
     defining attribute sets for other types of data.

     Technically, Z39.50 is not an International Standard;
     Z39.50 is an American National Standard.  However, there is
     an ISO standard called Search and Retrieval, ISO 10162/10163
     (service and protocol documents respectively), which was
     formally adopted to international standard status in 1991.
     SR is almost identical to a subset of Z39.50. Z39.50 has
     been revised to harmonise with SR, such that the American
     National Standard is a compatible superset of the
     International Standard.  These changes are included in the
     1992 revision.

     The NISSWAIS service

     NISS propose to mount a server of sources (databases) for
     public access.  Initially this will include sources
     containing the data from the Bulletin Board, the CHEST
     Directory and the NPDSA (HENSA) software description files,
     but already there are plans to mount several other software
     directories from all the major hardware systems vendors.

     The WAIS client interface to the Directory of servers is
     already accessible from the US menu of the NISS Gateway.
     This service lists all the sources that are currently
     published on the Internet.  The total number is increasing
     daily.  One or more sources can be selected and searched
     with a specific request.

     As the WAIS system develops, sources of information will
     proliferate, making it impossible for any user to keep track
     of all servers that may be available at any one time. To
     help solve this problem, Thinking Machines is maintaining a
     directory of servers in a widely accessible location.  This
     directory of servers contains indexed textual descriptions
     of all known servers.  It is queried just like any other
     source.  Instead of text documents however, it returns
     source structures which are specially formatted files that
     can be plugged into a question and used for queries.

     For example, suppose you needed information concerning the
     current gross national product of Mali but had no idea where
     to find it, you might first ask the directory of servers for
     information about the current economic condition of Mali.
     The directory would then return several documents, among
     which might be the source for the World Fact Book, an
     on-line almanac maintained by the CIA.  You would then use
     this document as the source field of a question and then
     re-run the query.  This time, the system would contact the
     almanac, ask for the information and return a document with
     the data you need.

     In order to make this service and indeed other Internet
     Protocol (IP) based services, available to the X29 based
     JANET community, the NISS Gateway passes the calls through
     an X29 to Telnet conversion switch at Bath before
     forwarding on to the Internet network.  Users may experience
     some connection problems to the US as the X29 to Telnet
     switch has proved to be less than 100% reliable.  It is
     hoped that these problems will be resolved in the near
     future.

     A VT100 NISSWAIS client interface will also be available
     from the Gateway for access to NISS and CHEST acquired data
     only.  It is hoped to provide an X Windows based client at
     some time in the future.

     NISS will continue to monitor the development of WAIS,
     Z39.50 and other parallel technologies, in an endeavour to
     provide convenient network access capabilities to the NISS
     databases of information.  There are currently a number of
     competing technologies and applications used for network
     information retrieval which are in various stages of
     development.  It is most likely that in the future a number
     of these will be successful in meeting the end user needs
     for accessing and retrieving network information.

     Eddie Zedlewski
     July 1992

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