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The Directory (CCITT X.500/ISO 9594) is an international standard, which was ratified jointly by ISO and CCITT in December 1988. The standard describes the structure and services of a global, logically centralized but physically distributed, electronic network directory that will support the evolving telecommunications environment. Directory pilot projects are underway in both North America and Europe and commercial implementations of the Directory standard are becoming increasingly available. As the bibliographic community becomes more dependent on the use of networks, it is essential that library professionals understand the capabilities of this powerful new standard.

The X.500 Directory Service is one of the most important tools ever produced for network users. It is the enabling mechanism for a revolution in communications among people worldwide. Initiating the service, however, can be fraught with problems—not the technical challenges of creating a globally distributed service with locally managed controls, but concerns raised by the very existence of a worldwide database of information relating directly to individuals. Opportunities opened up by the use of the Directory are inevitably accompanied by the possibility of misuse. Individual subjects of the information have divided views. They earnestly wish for easier contact with colleagues and others worldwide, while entertaining in varying degrees a fear of invasion of privacy or a violation of personal rights. Managements taking responsibility for their staff and students are reacting with caution to requests for information for inclusion in the Directory. These concerns must be taken seriously, or the service will fail—either by not reaching the critical mass that will make it useful, or by quickly becoming out of date and therefore irrelevant. Prospective Directory Service managers must lake considerable care to present the service in a reassuring way to their subjects and administrators, to convince them that the benefits greatly outweigh the risks, that controls exsist, and that responsible Directory use will benefit the world network community.

This special “theme” issue of Library Hi Tech is devoted to Open Systems Interconnection. The editor is Ray Denenberg, of the Library of Congress. Eleven articles cover the basic OSI platform, applications, support areas, and implementation. The basic OSI platform consists of protocols for the seven layers, including support for file transfer and message handling. Three articles describe network applications and the corresponding OSI services and protocols. “Information Retrieval as a Network Application” describes the ANSI Z39.50 protocol. Another article describes the interlibrary loan protocol, which incorporates the sequences of messages that occur in distributed interlibrary loan transactions. An article about electronic data interchange describes the edi conceptual model being developed by ISO, and its relationship to OSI. Network management and directory services are two of the most important OSI support areas; individual articles cover these two topics. Implementation topics include profiles, testing, and products.

The nature of information retrieval applications, the Z39.50 protocol, and its relationship to other OSI protocols are described. Through Z39.50 a client system views a remote server's database as an information resource, not merely a collection of data. Z39.50 allows a client to build queries in terms of logical information elements supported by the server. It also provides a framework for transmitting queries, managing results, and controlling resources. Sidebars describe the Z39.50 Implementors Group, the Z39.50 Maintenance Agency, and international standards for OSI library application protocols.

In September 1990, the U.S. Department of Education's Library Technology and Cooperation Grants Program awarded a three‐year grant to the Florida Center for Library Automation (FCLA), an agency of the Florida State University System, to develop software adhering to the ANSI Z39.50 Information Retrieval protocol standard. The Z39.50 software was to operate over the Open Systems Interconnect (OSI) communications protocols and be integrated with FCLA's NOTIS system, which is shared by all nine state universities in Florida. In order to test the correctness of its Z39.50 software, FCLA sought out other library software developers who would be willing to develop Z39.50 systems of their own. As part of this process, FCLA helped to found the Z39.50 Implementors' Group (ZIG), which has since gone on to improve the standard and promote Z39.50 implementations throughout much of the North American library systems marketplace. Early on in the project, it became apparent that TCP/IP would be a more heavily used communications vehicle for Z39.50 messages than OSI. FCLA expanded its design to include TCP/IP and, by the end of the grant in September 1993, will have a working Z39.50 system that can communicate over both OSI and TCP/IP networks.