The Global Directory Service (GDS) is a distributed, replicated directory service. It is distributed because information is stored in different places in the network. Requests for information may be routed by the GDS to directory servers throughout the network. It is replicated because information can be stored in more than one location for easier and more efficient access by its users.
GDS is based on the CCITT X.500/ISO 9594 (1988) international standard. The aim of this standard, also referred to as the OSI Directory standard, is to provide a global directory that supports network users and applications with information required for communications. The directory plays a significant role in allowing the interconnection of information processing systems from different manufacturers, under different management, of different levels of complexity, and of different ages.
GDS is the DCE implementation of the OSI Directory standard. Together with the Cell Directory Service (CDS), it provides its users with a centralized place to store information required for communications, which can be retrieved from anywhere in a distributed system. GDS maintains information describing objects such as people, organizations, applications, distribution lists, network hardware, and other distributed services dispersed over a large geographical area.
CDS stores names and attributes of resources located in a DCE cell. A DCE cell consists of various combinations of DCE machines connected by a network. Each DCE cell contains its own cell directory server, which provides access to local resource information. The CDS is optimized for local information access by its users. For a more detailed description of cells and their resource services, see the Introduction to OSF DCE.
GDS serves as a general-purpose information repository. It provides information about resources outside a DCE cell. It ties together the various cells by helping to find remote cells. A detailed discussion of the DCE namespace and its various servers and their interaction is provided in DCE Directory Service Overview.