Transcript What Is Z39.50?

Z39.50 and the JISC
Services
Brian Kelly
UK Web Focus
UKOLN
http://www.ukoln.ac.uk/
[email protected]
1
Who's Using It?
Which JISC services are currently
using Z39.50?
Which JISC services have tested
Z39.50?
2
The Problem
3
End users face difficulties due
to the wide variety of search
interfaces available
Possible Solutions
Agree to use the same software
Unlikely to happen
Undesirable
Agree to use implement similar interfaces
The Common User Interface (JISC) group gave
reasons why this wasn't sensible
Use software which implements protocol
designed to provide common search
interface across diverse services
Z39.50
4
What Is Z39.50?
Z39.50:
• A protocol which specifies data structures and
interchange rules that allow a client machine to
search databases on a server machine and
retrieve records that are identified as a result of
the search
• Maintained by Library of Congress
• Developed by ZIG
Why is it important?
• Powerful searching
• Local, familiar interface
• Retrieves structured data
5
What's It Look Like?
Z39.50 services can http://www.niss.ac.uk/
z3950/z3950.html
be accessed using
Web browsers.
NISS provides
access to:
• HEQC Access
Courses
Database
• CIA World
Factbook
6
Full Record
United Kingdom
<//COUNTRY
United Kingdom, Geography
Location:
Western Europe, bordering on the North Atlantic Ocean and the North
Sea, between Ireland and France
<//LOCATION
Map references:
Europe, Standard Time Zones of the World
<//MAPREF
Area:
total area:
244,820 sq km
land area:
241,590 sq km
comparative area:
slightly smaller than Oregon
note:
includes Rockall and Shetland Islands
Land boundaries:
total 360 km, Ireland 360 km
<//BOUNDARIES
What's It Look Like? (2)
Europagate is a Multifunctional Gateway
for Information Retrieval Protocols
http://europagate.dtv.dk/
7
Z39.50 Clients (1)
Dedicated Z39.50
clients are available.
Issues:
• Which is the best
client?
• Costs
• Additional software for
computing services to
support
8
Znavigator Client
Z39.50 Clients (2)
Z39.50 clients could be written in Java.
Issues:
• Client managed by
server provider
• Integrated with web
browser
• How widespread is
support for Java?
Contact
[email protected]
for details
9
Questions About Java
Is Java ready for prime time?
•
•
•
•
•
Widespread support in existing browsers
Support promised in operating systems
Minimises local installation/support effort
Exploit local PC processing power
Potential for negotiation over processing:
Server Do you do Java
Client No
Server OK, I'll do the processing and give you
the HTML
But:
10
???
Who Benefits?
End User
 Ease of use
 Productivity gains
Information Service Provider
 More effective use of service
 Service "hidden"
 Complex (?) Z39.50 software to support
Local Support Service (IT/Library)
 Reductions in user queries
 Extra client software to support
Where is the pressure for Z39.50 coming from?
11
Remember WAIS?
WAIS
• "Inspired" by Z39.50 (1988)
• Still used for searching sites
• Distributed searching did not take off - why?
At Leeds University:
• Computing Service
documents indexed using
WAIS (HTML and Postscript)
• WWWWAIS gateway used
• WAIS server not centrally
registered
• Work done in early 1994
12
Institutional Acceptance
Is it desirable for UK HEIs to run their own
Z39.50 servers?
How should searching across UK HEI's
web pages be achieved:
• Centralized harvest of pages
• Everyone running Z39.50 servers and
gateways
13
Potential For JISC Services
Image a chemist who wants to find out more
about CML (Chemical Markup Language) and
the Jumbo CML browser
find Jumbo and CML
Hits from
• HENSA archive of software
• Mailbase archives containing discussions
about the software
• A chemistry information gateway
14
Implementation Issues
What needs to be done to implement
a Z39.50 service?
• Systems issues
– server models
– client issues
• Other issues
– attribute set mapping
– etc.
15
Implementation Models
There are several models for running a
Z39.50 service across national services
WWW
server
Z39.50
Server
Z39.50
Gateway
WWW/Z39.50
Gateway
Information service providers run
Z39.50 and WWW gateway software
WWW-Z39.50 gateways provided:
(a) nationally
(b) distributed (organisations/regions)
Clients:
• Dedicated Z39.50 clients may be used
• Java Z39.50 clients may be used
• Web browsers may be used
16
UKOLN Experiences
Evaluating Europagate (gateway), Zebra and
Isite (Z39.50 servers) with:
•
•
•
•
17
eLib project descriptions
National Art Library
ADAM service
Ariadne
See pointer to
Experimental Z39.50 servers at
http://www.ukoln.ac.uk/
metadata/
Alternatives To Z39.50
Do Nothing
Do Like Me
Centralised Database
Harvest gathers
Use Other Protocols
LDAP
Whois++
Solutions At Other Levels
Application Layer
CORBA / IIOP
Distributed Objects (see MIDRIB)
18
What Next?
What should we do next?
• Agree on a model for JISC services?
• Agree on a diversity of models and share
experiences?
• Find out what others are doing?
• Find out about plans for client systems within
community?
Remember other technological developments
we'll have to consider:
19
XML
Cougar
Java
ActiveX
Metadata PICS
...
Stylesheets
Authentication
Further Information
For further information on Z39.50 see:
• UKOLN's list of resources at
http://www.ukoln.ac.uk/z3950/
• Z39.50 Client Survey at
http://www.dstc.edu.au/RDU/
reports/zreviews/z3950-clientsurvey.html
20
• DLIB article The Z39.50 Information Retrieval
Standard: Part I: A Strategic View of Its Past,
Present and Future at
http://hosted.ukoln.ac.uk/mirrored
/lis-journals/dlib/dlib/dlib/
april97/04contents.html