Frequently Asked Questions for Essence

Last-Changed:  December 23, 1993
URL:           <ftp://ftp.cs.colorado.edu/pub/cs/distribs/essence/FAQ.txt>

The following people have contributed to this FAQ:
     Darren R. Hardy <hardy@cs.colorado.edu>

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Question:  What is Essence?
Answer:

Essence is a resource discovery system based on customized information
extraction.  Essence can produce a compact, yet representative index
for large amounts of diverse information, then export the it via WAIS.

Essence supports application-specific, user-customizable means of
extracting and indexing information from a wide variety of UNIX file
system data.  By exploiting semantics of common file types, Essence
generates compact yet representative file summaries that can be indexed
and exported via the Wide Area Information Servers (WAIS) search and
retrieval interface.  People who wish to index data and search it using
WAIS can use Essence to index more file types than WAIS itself
currently supports, and to produce more space efficient indexes.


Question:  Where can I get more information about Essence?
Answer:

The Essence prototype is available via anonymous ftp; it's written in
Perl and C, and has been tested on SunOS 4.x systems.

    <ftp://ftp.cs.colorado.edu/pub/cs/distribs/essence/Essence.tar.Z>

If you would like to learn more about Essence, a paper is available via
anonymous ftp.

    <ftp://ftp.cs.colorado.edu/pub/cs/distribs/essence/Essence.ps.Z>
    <ftp://ftp.cs.colorado.edu/pub/cs/distribs/essence/Essence.txt.Z>

If you would like to be added to the essence-users list (for software
updates and other discussions, etc.), send an email message to
essence-users-request@cs.colorado.edu, with the body (not subject line)

    subscribe essence-users


Question:  Will Essence work with freeWAIS?
Answer:    

We've had reports that it will.  We've only made two (trivial) changes 
to the Thinking Machines, Inc. version of WAIS (WAIS-8-b5.1):

    1) We've added a new file type to 'waisindex' so that it supports
       Essence summary files (via the '-t essence' flag).
    2) We've modified the WAIS server so that it prepends all user 
       search strings with the keyword 'EssenceInterface'.  This is 
       so that every time a user queries a database, he/she will see 
       the EssenceInterface file (which describes how Essence works) 
       at the top of the returned documents.

With version 1.0 of Essence we had a report that our patches to
WAIS-8-b5.1 worked ok with freeWAIS after a little hacking.  I suspect
that the same is true with version 1.1 of Essence, since little has
changed w.r.t the WAIS modifications.

I took a quick look at freeWAIS-0.202.  I applied the patch file from
our distribution, fixed up the rejected hunks, and built a patch file
(src/Essence-freeWAIS.patch in the Essence distribution) that only
applies the file type modification (change #1 above) to freeWAIS.  It
should work, but I haven't tested it.