Z39.50 Discussion on Web4Lib

An interesting discussion on Z39.50 dying arose on Web4Lib today.  Because
the ZIG will be looking at the future of the standard, I thought this
email, which discusses one person's view of the technical side, might have
a place in your discussion.

Christine Peterson
Library Liaison Officer, Amigos Library Services
14400 Midway Road, Dallas, TX  75244-3509
800/843-8482 x191 (message only)
512/671-1580 (phone and fax)
EMAIL:  peterson@amigos.org

----- Forwarded by Chris Peterson/Amigos on 02/09/01 01:42 PM -----

Everyone,

There are scalability issues with Z39.50.  Multithreaded searching of more
than 5-7 institutions at a time can result in bottlenecks due to the
client/server communications overhead.  Standards for metadata harvesting
such as OAI are emerging to address the complexity and network bottleneck
issues of Z39.50.  Z39.50 uses, eseentially, the same registry concept that
RDF, digital certificates and handles technology employ.  However, the
client/server registry adds networking overhead.  I think that future
developments ought to divorce the registry aspect of Z39.50 from the client
and server and reference instead an independent "third-party" registry.
Z39.50 should only use client/server functionality, if needed, for tuning
the search engine to address the appropriate registry.   As search engines
get smarter, even this requirement would drop off. This would integrate
Z39.50 more tightly into XML-based distributed registry implementations,
such as RDF, which has never gotten off the ground, I think because it is
bound too tightly to the individual metadata record, which makes it very
cumbersome and labor-intensive to employ.

Z39.50 has a lot to offer that simpler harvesting protocols do
not--granularity of searching to nontextual atrributes, to holdings, to
segments of hierarchical records such as EAD Finding Aids.  I think the
protocol needs some fine tuning to reflect the realities of the distributed
web networking environment but I don't think it is replaced by technologies
such as OAI, but rather complemented by them.

Grace Agnew
grace.agnew@libvid2.library.gatech.edu

Received on Friday, 9 February 2001 14:47:20 UTC