positioning z39.50 in the networked library standards for building sustainable services william e....
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Positioning Z39.50 in the Networked Library Standards for Building Sustainable Services
William E. Moen<[email protected]>
School of Library and Information SciencesTexas Center for Digital Knowledge
University of North TexasDenton, TX 72603
Texas Library Association Conference 2003, April 2, 2003 Houston, TX
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Overview Putting Z39.50 in perspective … a bit of history Z39.50 uses and implementation in Texas The networked library Standards for building services
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Where did Z39.50 come from? Vision of library leaders in the 1970s Sharing bibliographic and authority records to create
a system of national bibliographic control Linking the major bibliographic utilities via computer
network
Standards development began in 1979 A protocol to support national bibliographic control…
Searching library catalogs Exchanging authority records (Linked Systems Project) Copy cataloging
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What Z39.50 was not planned for Did those library leaders envision the Internet, the
Web, and technologies of the 21st Century? Assumed a few large bibliographic systems would
use the protocol for record exchange Developed in the context of the Open Systems
Interconnection not in the context of the Internet and the Web
Widespread adoption in the library community and its integrated library systems
Use of the protocol outside of the library community
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Brief history of Z39.50 Pre-1979: The vision and ideas 1979: Standards development
initiated within library community 1984: Draft standard voted down
by NISO 1988: Approval of ANSI/NISO
Z39.50-1988 1992: Approval of ANSI/NISO
Z39.50-1992 1995: Approval of ANSI/NISO
Z39.50-1995 Late-1990s: Development of
Z39.50 profiles 2002: Approval of ANSI/NISO
Z39.50-2002
1970s: Experimental Internet
Late-1980s: Libraries get connected to the Internet via Telnet
Mid-1990s: Emergence of Web as real world application
Late-1990s/Early 2000s: XML, SOAP, Dublin Core, etc…
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What does Z39.50 offer? Information Retrieval (Z39.50): Application Service
Definition and Protocol Specification Allows
Searching of databases on one or more systems Retrieval of records from those system Without user having detailed knowledge of each system
Provides Search and retrieval of bibliographic and non-
bibliographic resources Technical foundation for information access and resource
sharing
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What are the benefits of Z39.50? Provides single interface for information access Enables integrated access to multiple and diverse
resources Supports simple and sophisticated searching Allows flexible and customizable retrieval Provides access control mechanisms Key technology for distributed information access in
the networked environment
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How is Z39.50 being used? To provide a common way to interact with databases
Serving up bibliographic records from online catalogs Serving up records from commercial databases Using a single interface to search databases
Information environments Libraries Commercial database providers Government information locators (e.g., TRAIL)
Applications Bibliographic citation software (e.g., Procite, EndNote) Portals Virtual libraries (e.g., Colorado, Illinois, Texas)
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ZLOT Technology Inventory & Assessment
Category Population Served Total # Percent Responses Percent
Small 0 – 10,000 321 58.3 152 51.9Medium 10,001 - 100,000 199 36.1 119 40.6Large 100,001 or more 31 5.6 22 7.5TOTAL 551 100% 293 100%
Category Enrollment (FTSE) Total # Percent Responses Percent
Small Less than 2,000 48 32.7 21 28.0Medium 2,001 – 9,999 75 51.0 41 54.7Large 10,000 or more 24 16.3 13 17.3TOTAL 147 100% 75 100%
Public Libraries
Academic Libraries
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Z39.50 servers operating in Texas
79%
58%
84%
43%
31%
47%
65%61%
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
2-Year Academic Public Sample
Included
Running
Source: ZLOT Technology Inventory and Assessment Survey, 2002
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Z39.50 clients operating in Texas
88%78%
68%
43% 51%57% 55%
64%
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
2-Year Academic Public Sample
Included
Running
Source: ZLOT Technology Inventory and Assessment Survey, 2002
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How is it used in Texas libraries?
0%10%20%30%40%50%60%70%
Other
Exper
imen
tal
Patro
ns
Refer
ence
Ser
vices
Tech
nical
Servic
es
2-Year
Academic
Public
Sample
Source: ZLOT Technology Inventory and Assessment Survey, 2002
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So, what’s the bad news? Early Z39.50 clients
and servers: Needed much care
and feeding Were not easy to use
Little interoperability Differences in how
vendors implemented the standard
Little consensus on how to make it work
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What’s changed/changing? Problems of interoperability are better understood
Search functionality of local systems Local indexing decisions
Z39.50 profiles have been developed Detailed specifications for using Z39.50 in particular
applications• The Bath Profile: An International Z39.50 Specification for
Library Applications and Resource Discovery• U.S. National Z39.50 Profile for Library Applications• Z Texas Profile for Library Applications
Conformance to profiles by vendors and libraries Interoperability testing can help improve systems
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What’s changed/changing?
Interfaces are becoming more usable
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What’s changed/changing?
Number of Z39.50 accessible resources increasing
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Are there alternatives to Z39.50? It depends… what application/service do you want? And there are tradeoffs… what costs are incurred? Possible alternatives
Have users search individual databases through native interfaces – web interfaces make this a bit easier
Build large repositories of metadata (e.g., OAI) Use customized translators and scripts (e.g. WebFeat) Wait for new protocols and technologies (e.g., XML
standards such as XML Query, XPath, etc.) Evolution of Z39.50 for the web environment…
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ZING – Z39.50 International Next Generation Make intellectual/semantic content of Z39.50 more
broadly available Make Z39.50 more attractive by lowering barriers to
implementation Use of XML – to represent and encode data Use of HTTP – for transport Use of SOAP – for interaction between client and server
based on Remote Procedural Call (RPC) Several initiatives: ZOOM, ez39.50, ZeeRex,
SRW/UFOR MORE INFORMATION, VISIT THE PROJECT WEBSITE…
http://www.loc.gov/z3950/agency/zing/zing.html
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Search/Retrieve Web Service – Overview Builds on Z39.50 and web technologies Retains Z39.50 concepts:
Results sets Abstract access points Abstract record schemas Explain & Diagnostics
Web technologies: XML, SOAP/RPC, HTTP Combines several Z39.50 features into two “operation types”
Search/Retrieve Explain
Provides a standards-based method for representing and issuing queries, and retrieving records
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SRW and Classic Z39.50 Lightweight SRW clients Gateways between SRW and classic Z39.50 SRW queries should map to Z39.50 queries
CQL Z39.50 attribute combinations Retrieval records returned to SRW gateway
Transformed from a Z39.50 record syntax to XML
FOR MORE INFORMATION, VISIT THE PROJECT WEBSITE…
http://www.loc.gov/z3950/agency/zing/zing.htmlhttp://www.loc.gov/z3950/agency/zing/srwu/implementors.html
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The library in the networked environment… Collections of resources – local and distributed Collaborative services and activities Tools that assist users in networked information
resource discovery and access Services that help users
answer questions, learn about the collection, learn about the bibliographic tools, and generally connect users to appropriate resources
A management structure that allocates resources and policies for inter-organization collaboration
Extends the reach and range of users
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Networked library components User groups
Local, onsite Distributed, remote
Services Local Collaborative Remote
Resources Information
• Local• Distributed
Human
Technology Local applications Distributed applications Standards
Management Local Collaborative
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Characterizing the networked library Virtual library components An environment for provision of
Services Resources
Not a digital library Not all resources available are in digital/electronic form
An evolving product that responds to Users’ needs Available resources Current and emerging technologies
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Service-centric virtual library
UserGroups
Resources
Technology
Management
SERVICES
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User-driven services
LIBRARY SERVICES
UserGroup
UserGroup
UserGroup
UserGroup
LibraryResources
LibraryTechnology
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Library services for the networked library Infrastructure/internal
Collection identification, selection, and acquisition/access
Collection building and digitization
Collection organization and preparation
Inter-organization access Trust and authentication Billing and payment Preservation and archiving
Patron Resource discovery service Access service Reference service Instruction service Patron account service
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Building services for the networked library What are the requirements for the services? What are alternatives for deploying the services? What technologies are available to support the
services? What standards are available? What are the tradeoffs of standards and non-
standards approaches?
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Infrastructure standards -- NISO ANSI/NISO Z39.50: Information Retrieval (Z39.50): Application
Service Definition and Protocol Specification ISO 10160 & ISO 10161: Interlibrary Loan Application Service
Definition & Protocol Specification ANSI/NISO Z39.83: Circulation Interchange Protocol (NCIP) ANSI/NISO Z39.84: Syntax for the Digital Object Identifier - 2000 ANSI/NISO Z39.85: Dublin Core Metadata Element Set - 2001 ANSI/NISO Z39.88: The OpenURL Framework for Context-Sensitive
Services (2002) ANSI/NISO Z39.89:The U.S. National Z39.50 Profile for Library
Applications (2002) Networked Reference Services (standards development underway) MetaSearch Initiative (may lead to new standards activities)
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Standards supporting services Each standard enables different services
Networked information retrieval (Z39.50) Automated interlibrary loan (ILL) Circulation applications (NCIP) Reference linking (OpenURL) Resource description (Dublin Core)
But they can work together to support robust and interoperable information access and resource sharing services
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Opportunities and challengesSo many users, resources, technologies, standards! A service-based framework provides a context for rational
response: For choosing and developing services For identifying and selecting appropriate technologies and
standards The networked library requires more agreements and
support of standards and … Collaboration
Vendors Content providers Libraries Funding agencies