CORBA 2.3.3 Getting Started Guide (NonStop CORBA 2.3.3+)

An application model that separates the user-interface functions, transaction processing functions, and
database functions is called a three-tiered architecture. Object technology is suited to many different types of
application models, varying in both the types and the number of tiers.
Client/Server Computing with NonStop CORBA
Compaq NonStop CORBA applications are client/server applications that run on Common Object Request
Broker Architecture (CORBA) 2.3-based computer systems and networks. While clients and servers can be
running on the same Compaq system, NonStop CORBA servers can also handle remote client requests. Also,
NonStop CORBA clients can make requests that are fulfilled by remote NonStop CORBA servers and
servers on other ORBs".
NonStop CORBA application servers are CORBA-based server processes that run on the Compaq NonStop
Kernel operating system. The application server acts as a server process for clients both local and remote to
the NonStop CORBA system.
NonStop CORBA clients are CORBA client processes that also run on the NonStop Kernel operating
system. As CORBA clients, they can either reside on the same system as the NonStop CORBA application
server that processes their requests, or they can act as a "network" or "remote" clients by interoperating
across a network to an application server located on another computer that may use another vendor's
CORBA-compliant ORB.
With NonStop CORBA, a network client need not be aware of where the application server is located; when
a network client makes a request of an object, the NonStop CORBA software transparently establishes a link
with the server to handle the client's request.
The Benefits of Distributed Object Computing
The application of object-oriented technology to distributed processing offers several advantages to
programmers and organizations:
Reuse of existing components●
Convenient evolution and specialization of services●
Insulation of client programs from server implementation details●
Migration and integration of legacy applications●
Reuse of Existing Components
The possibility of reuse exists because a programmer can design general-purpose object classes and package
them as class libraries and frameworks for use by new applications. Reuse allows new software to be
developed faster, at lower cost, and with higher quality than if a project required all new code and testing.
Off-the-shelf components from different vendors can be used to construct new applications. This approach,
called component-based development, allows an organization to concentrate its efforts on developing
specialized functions rather than reinventing the functions common to many applications.
Convenient Evolution and Specialization of Services