Does annotation need a huge central data base?

 > Misha Glouberman <misha@the-wire.com> writes:
 > > ... I recognize
 > > that a central public comments database would be huge- definitely too big
 > > for a single publicly-minded individual or organization to maintain out of
 > > altruism or in the name of research.

Jacob Palme writes:
 > An annotation system does not need a large central data base.

 > The main principle should be that annotations are stored close to the
 > server which stores the annotated message.

I believe the issue Misha is addressing by suggesting a central data base
is one of control.  The publically available annotations of a document
might not be compatible with the policies of the server of the
document; the administrators might want to suppress the annotations in
fact.  So these annotations would either not be available or must be
available through some administratively separate server.

Now the problem for the user who wishes to see the annotations is how
to find this separate server.  So there are problems either way: a
problem of control by the servers of documents being annotated and, if
not that, a problem of finding the annotations.

A few centralized databases for all annotations of all documents would
solve these problems, but it would create new problems.  Control by
the centralized databases is obviously a problem.  The scaling problem
is also very severe.  The early NCSA public annotation server was
drowned with too many requests.  After all, we are talking about
asking the annotation server for annotations anytime any user visits
any page.

I think the solution has to be many more annotation servers focused on
much smaller user groups and smaller sets of documents.  It is also
useful to have approved annotation servers be advertised by the server
of documents being annotated.  Jacob's suggestion of a way to compute
the annotation server from the original document URL is interesting,
but it is easy enough for the server to return an explicit reference
to the approved annotation servers.  NCSA httpd actually has a
configuration option that supports this.

--
Daniel LaLiberte (liberte@ncsa.uiuc.edu)
National Center for Supercomputing Applications
http://union.ncsa.uiuc.edu/~liberte/

Received on Friday, 9 August 1996 14:05:46 UTC