1. Z39.50 and the ZING Initiatives: MAVIS Users Conference, 2003 November 6, 2003 Larry E. Dixson ldix@loc.gov Library of Congress

2. Presentation Overview l Z39.50 Description and History l Z39.50 Maintenance l Z39.50 Interoperability l Z39.50 Profiles l ZING Initiatives

3. Z39.50 Description l National and international standard l Client / server environment l Client developer controls display l Examples: »Language preference »System display preference »Retrieve records into an application

4. Z39.50 Historical Development 1982: LSP/ Information Retrieval 1983: LSP/IR submitted as ANSI standard 1984: ISO SR introduced 1988: NISO Z39.50-1988 1990: LC Maintenance Agency 1990: Z39.50 Implementors’ Group 1991: ISO SR approved (10162-10163) 1992: NISO Z39.50-1992 1995: NISO Z39.50-1995 1998: ISO IR 23950 2000: ZING (Z39.50 International: Next Generation)

5. Z39.50 Maintenance l Z39.50 Maintenance Agency at LC »http://lcweb.loc.gov/z3950/agency/ »Editor: Ray Denenberg (rden@loc.gov) »Z39.50-1995 Document l Z39.50 Implementors’ Group »http://lcweb.loc.gov/z3950/agency/zig/zig- meetings.html »http://lists.w3.org/Archives/Public/www-zig/

6. Z39.50 Interoperability Why aren’t all Z39.50 implementations the same? l Z39.50 implemented by existing, mature search systems with different search behavior l Indexing not standardized across systems l Bibliographic community did not profile prior to implementing protocol in 1992 – search functionality was decided by each system vendor l Implementors sometimes differed on interpretation of the standard

7. Z39.50 Profiles l Profiles developed by committee »Customer base »Vendors »Protocol experts l Reasons for profiles »Specification for vendors (interoperability) »Specification for customers (procurement)

8. Z39.50 Profile Examples l Bath Profile (International) »http://www.nlc-bnc.ca/bath/tp-bath2-e.htmhttp://www.nlc-bnc.ca/bath/tp-bath2-e.htm l US National Profile (Z39.89) »http://www.unt.edu/zprofile/Profile/specificatio ns.htmhttp://www.unt.edu/zprofile/Profile/specificatio ns.htm l Other Profiles »http://lcweb.loc.gov/z3950/agency/profiles/profi les.htmlhttp://lcweb.loc.gov/z3950/agency/profiles/profi les.html

9. Z39.50 Characteristics l Large, complex standard, rich in functionality l Implementations are subsets of the standard l Pre-dates the Web – connection oriented and transfer syntax not human readable l Z39.50 session data units: –TCP/IP (request and response) –Initialization (request and response) –Search (request and response) –Present (request and response) –Close (request and response)

10. Z39.50 Search Request attributeType1 numeric1003 attributeType2 numeric3 attributeType3 numeric1 attributeType4 numeric1 attributeType5 numeric1 attributeType6 numeric1 Term61 76 72 61 6D 2C 20 68 65 6E 72 69 65 74 74 65

11. ZING Initiatives ZING (Z39.50 International: Next Generation) –http://www.loc.gov/z3950/agency/zing/zing-home.html »SRW (Search / Retrieval Web Service) »SRU (Search / Retrieval URL) »CQL (Common Query Language) »ZOOM (Z39.50 Object-Orientation Model) »ez3950 » ZeeRex (Z39.50 Explain, Explained and ReEngineered in XML)

12. SRW Search/Retrieve POST / srw.loc.gov/LCDB HTTP/1.1 [... ] bath.author=“^avram,henriette” 1 10 http://www.loc.gov/mods/

13. SRU Search/Retrieve http://sru.loc.gov/LCDB/searchRetrieve?query= bath.author=^avram,henriette”&maximumRec ords=10&recordSchema=http%3a//www.loc.g ov/mods/&startRecord=1

14. CQL Examples l Author Search – First words in field bath.author=“^avram, henriette” l Title Search – Exact match bath.title exact “xml & sgml cookbook” l Other examples cat and fish (((cat or dog) or horse) and frog) cat prox/word/=/3/ordered hat

15. ez3950 Uses XER (XML encoding rules) over SOAP to encode Z39.50 ASN.1 data units http://www.lib.ox.ac.uk/jafer/ez3950/ez3950.html

16. ZOOM ZOOM (Z39.50 Object-Orientation Model) Specifications for API bindings exist in: C, C++, Perl, Java, Visual Basic, etc. http://zoom.z3950.org/index.html

17. ZeeRex ZeeRex (Z39.50 Explain, Explained and ReEngineered in XML) XML schema used to describe the configuration and capabilities of Z39.50 and SRW/SRU servers: http://explain.z3950.org/

18. Summary l Z39.50 widely deployed in library community l Z39.50 still an essential tool to provide access to library catalogs l ZOOM API and toolkits hide complexity of Z39.50 implementation l SRW, SRU, ZeeRex, and ez3950 growth is not easy to predict at this time

19. Questions