OSF DCE Application Development Guide--Core Components

RPC and Other DCE Components
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An individual user can have a personalized user profile that contains elements for
interfaces the user uses regularly and a default element that specifies a public profile,
such as the cell profile, as the default profile. NSI searches use the default profile
when a client needs an RPC interface that lacks an element in the user profile.
14.3.4 The Service Model for Defining Servers
The NSI operations accommodate two distinct models for defining servers: the
service model and the resource model. These models express different views of how
clients use servers and how servers can present themselves in the directory service
database. The models are not mutually exclusive, and an application may need to
implement both models to meet diverse goals. By evaluating these models before
designing an RPC application, you can make informed decisions about whether and
how to use object UUIDs, how many server entries to use per server, how to
distinguish among instances of a server on a system, whether and how to use groups
or profiles or both, and so forth. The two models are the service model and resource
model.
The service model views a server exclusively as a distributed service composed of
one or more application-defined interfaces that meet a common goal independently of
specific resources. The service model is used by applications whose servers offer an
identical service and whose clients do not request an RPC resource when importing
an interface. Often, with the service model, all the server instances of an application
are equivalent and are viewed as interchangeable. However, the service model can
accommodate applications that view each server instance as unique. The
implications of whether server instances are viewed as interchangeable or unique are
significant, so the following subsections address these alternatives separately.
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