Outside of the DCE cells and their separate namespaces is the global namespace in which the cell names themselves are entered, and where all intercell references are resolved. Two directory services participate in the global namespace. The first is the X.500-compliant GDS supplied with DCE. The second is DNS, with which DCE interacts, but is not a part of DCE.
The global and cell directory services are accessed implicitly by RPC applications using the NSI interface. GDS and CDS can also be accessed explicitly using the XDS interface. With XDS, application programmers can gain access to GDS, a powerful general-purpose distributed database service, which can be used for many other things besides intercell binding. XDS can also be used to access the cell namespace directly, as this topic describes.
An XDS application looks very different from the RPC-based DCE applications. This is partly because there is no dependency in XDS on the DCE RPC interface, although you can use both interfaces in the same application. Also, XDS is a generalized directory interface, oriented more toward performing large database operations than toward fine-tuning the contents of RPC entries. Nevertheless, XDS can be used as a general access mechanism on the CDS namespace.
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