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distributed objects |
Distributed objects are
pieces of data in their own little world, yet they are "in vogue" for distributed computing systems.
They not only have a standard interface, but are independent of the application, language, and
platform. Distributed objects are like building blocks, and can be combined with each other to
make different applications (See Figure 2).
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Fig. 2: Distributed Objects
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For example, Microsoft Office's suite of applications — Word, Excel, and Powerpoint — all share
many similarities using the concept of distributed objects. They share the same Open/Save dialog
boxes, the same spell checker, and the same drawing tools, because each application consults an
object independent of the actual applications' coding. These objects aren't quite distributed, for
they work on whatever operating system they were designed for, but they come close to being
distributed objects.
Distributed objects are poised to replace remote procedural calls as the standard of
communication between distributed applications since they are suitable for complex applications
(Seltzer). They are able to roam through a network, work with other components, and
clean up after themselves.
Distributed objects are able to communicate with each other
through set standards, of which there are two major specifications. CORBA, or Common Object
Request Broker Architecture, handles communication by using ORB's, or object request brokers.
If the application wishes to access an object, it must go through an ORB first. Microsoft's
Distributed COM simply allows objects to communicate with each other.
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