Z39.50.pptx

Z39.50 :An Information Retrieval Protocol.
The development of online bibliographic databases and the rapid growth of online services accessible on the internet and world wide web (WWW) has made it possible to access information in ways not possible before. Libraries, whose primary mandate is to provide information, shifted the emphasis from collecting the information in hard copy to accessing information through electronic resources.

1. Dr.P.PADMA Assistant Professor DOLIS Z39.50 :An Information Retrieval Protocol

2. Introduction The development of online bibliographic databases and the rapid growth of online services accessible on the internet and world wide web (WWW) has made it possible to access information in ways not possible before. Libraries, whose primary mandate is to provide information, shifted the emphasis from collecting the information in hard copy to accessing information through electronic resources.

3. Contd.. However, the major problem is of variation in software and hardware. Library professionals have to learn the specific features of each system, i.e., command languages, search procedures, etc. More the electronic resources grow; more will be the confusion on how to access the information of so many diverse databases. Another problem is the ability of many diverse database structures and different application designs to exchange information electronically. ANSI/NISO, Z39.50 standard was developed to share the bibliographical information electronically and to overcome the problems of database searching with many search languages.

4. A standard presents an agreement on how to do something or carry out some activity to arrive at predictable results. All standards published by the National Information Standards Organization (NISO) are developed by a consensus process that draws on the expertise of implementors and vendors, product developers , and users of those products they are approved by the American National Standards Institute. What is a Standard?

5. Why standards are necessary ? Standards are necessary for networking and for information exchange. Eg. MARC and Z39.50 allow searching, retrieval and exchange of records across platforms and its Unicode allows encoding, searching and retrieval of information in different scripts.

6. Library Automation Standards: Standards adopted by the library industry and community which facilitate data interchange between libraries and institutions and are supported by most systems are MARC (Machine Readable Cataloguing) standards and Z39.50, the information search and retrieving protocol standard

7. WHAT IS Z39.50 Protocol? Z39.50 is an  international standard   client–server ,  application layer   communications protocol  for searching and retrieving information from a  database  over a  TCP/IP   computer network . It is covered by  ANSI / NISO  standard Z39.50, and  ISO  standard Z39.50. The standard's maintenance agency is the  Library of Congress . Z39.50 is widely used in  library  environments, often incorporated into integrated library system and personal  bibliographic reference software . Interlibrary catalogue searches for  interlibrary loan  are often implemented with Z39.50 queries.

8. Contd.. Z39.50 is an international standard protocol used by net- worked computer systems for information retrieval. It enables information seekers to search different systems on a network or the Internet through the use of a single user interface. Software and system vendors offer access to information from a diversity of unique systems with different hardware, software, interfaces, and data-base search commands. The goal of Z39.50 is to reduce the complexity and difficulties of searching and retrieving information. Z39.50 makes it easier to use the wealth of information re- sources on the Internet. When using Z39.50-enabled systems, a user in one system can search for electronic information in another system without having to know how that system works .

9. History The name Z39.50 comes from the fact that the National Information Standards Organisation (NISO), a standard developer for American National Standards Institute(ANSI) was once the Z39 committee of ANSI. NISO standards are numbered sequentially and Z39.50 is the fifth standard developed by NISO. NISO approved the original Z39.50 standard in 1988 . It was developed as an application layer of the OSI(Open System Interconnection) communication model. Z39.50-1988 is now out-dated and incompatible with later Z39.50 versions. It formed the basis of the wide area information server (WAIS) protocol.

10. Contd.. Z39.50 has progressed through three versions, with each version adding vastly greater functionality and sophistication. Version 1 defined the core services of Z39.50. Version 2 formalized the structure of information to be exchanged based on the ISO standard data description language and encoding rules known as ASN.1 and BER. With consensus on Z39.50 version 2, vendors began to create applications rapidly and momentum grew for compliance with Z39.50 functionality. Version 3, the current version of the standard, builds on and includes version 2. Version 3 is extremely powerful in its support for simple to highly complex applications. The current version of the Z39.50 standard is formally known as ANSI/ NISO Z39.50-1995, Information Retrieval—Application service definition and protocol specification. The International Organization for Standardization (ISO) approved two information retrieval standards in 1993 (ISO 10162 and ISO 10163-1). In 1998, ISO adopted the Z39.50 protocols and issued ISO 23950.

11. How does Z39.50 work?

12. Contd..

13. Solutions of Z39.50 Originally Z39.50 was designed to help with searching very large bibliographic data- bases like those of OCLC and the Library of Congress. Z39.50 is used for a wide range of library functions that involve database searching, from cataloguing to interlibrary loan to reference. With the rapid growth of the Internet, the Z39.50 standard has become widely accepted as a solution to the challenge of retrieving multimedia information including text, images, and digitized documents. Z39.50 is being used to access, for example, museum data, government information, and geospatial data. It can also be used to search the online databases and CD-ROMs that vendors develop according to a variety of design schemes. With- out having to learn each system, users can search those databases with a single Z39.50 client, even though each uses a different hardware and software configuration, stores different types of data, and has different internal search logic.

14. Benefits Seamless access : This seamless access to multiple, diverse databases through a single interface is Z39.50’s greatest benefit. Resource sharing: Z39.50 can encourage re broadcast searching of library catalogues located on the Internet anywhere in the world, interlibrary loan through Z39.50’s standardized approach for delivering holdings information, and online item ordering and document delivery. Increased Productivity Staff training time can be reduced for functions that require database searching, such as cataloguing, acquisitions, and interlibrary loan. Easier access to electronic resources reduces all users’ time spent in searching for relevant information .

15. The basic function of Z39.50 is to negotiate a connection be- tween the client and server on two systems, execute a search, and return the formatted results to the user’s screen. In a Z39.50 session, the Z39.50 client soft- ware that initiates a request for the user is known as the Origin. The Z39.50 server software system that responds to the Origin’s request is called the Target Key features of Z39.50

16. Facilities and services Z39.50 is divided into eleven basic facilities. Each facilities. Each facility is divided into one or more service. A service facilitates a particular type of operation between the client and the server out of eleven facilities, three are core facilities and they are Initialisation, Search and Retrieval.

17. Initialisation The Initialization Facility allows the Origin (client) and Target (server) to negotiate and establish a Z39.50 search session, known as a Z-Association. This facility establishes the rules by which the client and server will operate. Establishing the rules involves sharing information about the version of the protocol being used by client and server, default character set, size and limits on records to be transferred, and other Z39.50 features, e.g., sorting, browsing, and deleting result sets .

18. Search Facility Allows the user to formulate a search query using an interface format familiar to the user. Z39.50 provides a rich vocabulary for ex- pressing search queries. The user may identify specific fields to search (i.e., access points) and may create complex searches using Boolean operators, truncation, and other advanced searching techniques. Z39.50 also supports the main- taining of multiple search results and combining the results of those searches.

19. Present Facility Allows the user to request that some or all of the records identified as meeting the search criteria be transmitted from the server to the client. This facility also sup- ports selection of data elements to include and format for transferring the records.

20. Other Z39.50 Facility protocols exist to support such features as Sort the results as specified by the user. Delete search results, either entirely or for specified re- cords. Scan (browse) through index lists of items such as subject terms, titles, author names, and other database fields. Access Control through authentication and passwords. Resource Control and termination of Z39.50 search sessions by the client or server.

21. Contd.. Two newer facilities, not readily available yet in many implementations are Explain Which allows the client to exchange information with the server about what type of server the client is querying and what the client must do to communicate successfully with that server in a Z39.50 session, and Extended Services Which define operations the client may request of the server, such as saving a search for later re-use or running a search query on a periodic schedule.

22. Advantages of Z39.50 Any database that is Z39.50 enabled may be searched by using a single search interface a single set of search commands and search strategies. Allows intersystem searching and record transfer irrespective of different software and hardware. Multi-database searching using single search interface. Virtual union catalogue--a combined catalogue of several libraries on diverse systems (without merging the catalogues) is possible. Z39.50 clients will permit searching of members' collections with a single interface. I nterlibrary loans (ILL) process will be made easier. Extended services for ordering documents, updating databases and sorting searches can be defined and controlled via Z39.50. Records can be displayed in any flavour of MARC. In addition, work is going on to use generic set of data element called Dublin , Core to use as attribute set and record syntax. CD-ROM databases from various vendors could be searched with a single interface. The time and expense of training users on multiple interfaces could be reduced. The SDI or selective dissemination of information service could be set to run a saved search in the catalogues of many different libraries regularly and automatically with results being sent to the user by fax or e-mail

23. DISADVANTAGES OF Z39.50

24. Conclusion The Z39.50 protocol not only rescues a librarian from learning different search interfaces for different databases, it also helps the librarian to improve resource sharing among libraries by virtual union catalogue and ILL. Z39.50 also allows users to specify search statement to be saved and run at intervals. This greatly helps the librarian in providing the SDI service.