Well, I know the Z39.50 only as an international standard client/server, application layer communications protocol for searching and retrieving information from a database over a TCP/IP computer network.

Dear Surendra,

We can défine Z39.50 as server or as protocol :

-In Evergreen versions preceding 2.2, all users with cataloging privileges could view all of the Z39.50 servers that were available for use in the staff client. In Evergreen version 2.2, you can use a permission to restrict users' access to Z39.50 servers. You can apply a permission to the Z39.50 servers to restrict access to that server, and then assign that permission to users or groups so that they can access the restricted servers.

-Also Z39.50 is commonly used to refer to the service and protocol defined by International Standard ISO 23950: Information Retrieval (Z39.50) - Application Service Definition and Protocol Specification and ANSI / NISO Z39. 50.

For more details please see links and attached files in subject.

List of Z39.50 Servers | BiblioTech Libraries

https://www.bibliotechzw.com/blog/list-of-z39-50-servers/

Test Search Form for Z39.50 Servers

https://www.loc.gov/z3950/test.html

Adding and Configuring Z39.50 Servers - MarcEdit - LibGuides at ...

guides.library.illinois.edu › LibGuides › MarcEdit

Information Retrieval (Z39.50): Application ... - Library of Congress

https://www.loc.gov/z3950/agency/Z39-50-2003.pdf

Z39.50 Access What is Z39.50? Z39.50 is a protocol which specifies ...

https://www.unigre.it/.../scheda_completa_parametri_Z3950_en.pd...

Best regards

39.50 - National Information Standards Organization

The Z39.50 standard for information retrieval is important from a number of perspectives. While still not widely known within the computer networking community, it is a mature standard that represents the culmination of two decades of thinking and debate about how information retrieval functions can be modeled, standardized, and implemented in a distributed systems environment. And - importantly -- it has been tested through substantial deployment experience.

Z39.50 is one of the few examples we have to date of a protocol that actually goes beyond codifying mechanism and moves into the area of standardizing shared semantic knowledge. The extent to which this should be a goal of the protocol has been an ongoing source of controversy and tension within the developer community, and differing views on this issue can be seen both in the standard itself and the way that it is used in practice. Given the growing emphasis on issues such as "semantic interoperability" as part of the research agenda for digital libraries (see Clifford A. Lynch and Hector Garcia-Molina. Interoperability, Scaling, and the Digital Libraries Research Agenda, Report on the May 18-19, 1995 IITA Libraries Workshop, ), the insights gained by the Z39.50 community into the complex interactions among various definitions of semantics and interoperability are particularly relevant.