Overview of Wide Area Information Servers
			      Brewster Kahle
				April 1991


The Wide Area Information Servers system is a set of products supplied by
different vendors to help end-users find and retrieve information over
networks.  Thinking Machines, Apple Computer, and Dow Jones initially
implemented such a system for use by business executives.  These products
are becoming more widely available from various companies.

What does WAIS do?
	Users on different platforms can access personal, company, and
published information from one interface.  The information can be anything:
text, pictures, voice, or formatted documents.  Since a single
computer-to-computer protocol is used, information can be stored anywhere
on different types of machines.  Anyone can use this system since it uses
natural language questions to find relevant documents.  Relevent documents
can be fed back to a server to refine the search.  This avoids complicated
query languages and vendor specific systems.  Successful searches can be
automatically run to alert the user when new information becomes available.


How does WAIS work?   
	The servers take a users question and do their best to find
relevant documents.  The servers, at this point, do not "understand" the
users english language question, rather they try to find documents that
contain those words and phrases and ranks then based on heuristics.  The
user interfaces (clients) talk to the servers using an extension to a
standard protocol Z39.50.  Using a public standard allows vendors to
compete with each other, while bypassing the usual proprietary protocol
period that slows development.  Thinking Machines is giving away an
implementation of this standard to help vendors develop clients and
servers.

What WAIS servers exist?   
	Even though the system is very new, there are already several
servers: 
  * Dow Jones is putting a server on their own DowVision network.
This server contains the Wall Street Journal, Barons, and 450 magazines.
This is a for-pay server.  
  * Thinking Machines operates a Connection Machine on the internet for
free use.  The databases it supports are some patents, a collection of
molecular biology abstracts, a cookbook, and the CIA World Factbook.  
  * MIT supports a poetry server with a great deal of classical and
modern poetry.  Cosmic is serving descriptions of government software
packages.  The Library of Congress has plans to make their catalog
available on the protocol.  
  * Weather maps and forecasts are made available by Thinking Machines as a
repackaging of existing information.  
  * The "directory of servers" facility is operated by Thinking Machines so
that new servers can be easily registered as either for-pay or for-free
servers and users can find out about these services.

How can I find out more about WAIS?   
	Contact Brewster Kahle for more information on the WAIS project,
the Connection Machine WAIS system, or the free Mac, Unix Server, and X
Window System interfaces.  There is a mailing list that has weekly postings
on progress and new releases; to subscribe send and email note to
wais-discussion-request@think.com.

Brewster Kahle
Project Leader
Wide Area Information Servers
Brewster@Think.com