A DCOM client calls into the exposed methods of a DCOM server by acquiring a pointer to one of the server object's interfaces. Integrative Programming and Technologies 11 11ġ2 DCOM as DS technology Solution DCOM servers object can support multiple interfaces each representing a different behavior of the object. On the other end, DCOM creates another wrapper, called a stub, which marshals methods calls and routes them to an instance of the component. This wrapper, called a proxy, simply marshals methods calls and routes them across the network. Integrative Programming and Technologies 10 10ġ1 DCOM as DS technology Solution When the client instantiates a component whose registry entry suggests that it resides outside the process space DCOM creates a wrapper for the component and hands the client a pointer to the wrapper. DCOM works over the network by using proxy's and stubs. It currently supports Java(J++),C++, Visual Basic, JScript, and VBScript. Integrative Programming and Technologies 9ġ0 DCOM as DS technology Solution It is the distributed version of Microsoft's COM technology which allows the creation and use of binary objects/components from languages other than the one they were originally written in. There are many different choices that can be made in doing so. The actual realization of a distributed system requires that we instantiate and place software components on real machines. The software architectures tell us how the various software components are to be organized and how they should interact. Integrative Programming and Technologies 8ĩ Architectures for Integrating Systems. There are different ways on how to view the organization of a distributed system, The organization of distributed systems is mostly about the software components that constitute the system. To master their complexity, it is crucial that these systems are properly organized. Integrative Programming and Technologies 7Ĩ Architectures for Integrating Systems Distributed systems are often complex pieces of software of which the components are by definition dispersed across multiple machines. Integrative Programming and Technologies 6ħ Intersystem Communication. Accordingly, such a distributed system is sometimes called middleware. In order to support heterogeneous computers and networks while offering a single-system view, distributed systems are often organized by means of a layer of software-that is, logically placed between a higher-level layer consisting of users and applications, and a layer underneath consisting of operating systems and basic communication facilities.

Integrative Programming and Technologies 5Ħ Intersystem Communication. This means that one way or the other the autonomous components need to collaborate. A second aspect is that users (be they people or programs) think they are dealing with a single system. The first one is that a distributed system consists of components (i.e., computers) that are autonomous. This definition has several important aspects. A distributed system is a collection of independent computers that appears to its users as a single coherent system. A distributed system relies entirely on the underlying computer network for the communication of data and control information between the nodes of which they are composed Integrative Programming and Technologies 4ĥ Intersystem Communication. A distributed system is basically a computer network. Intersystem communication is used in distributed computing. Integrative Programming and Technologies 3Ĥ Intersystem Communication. The means for communication among processors, memory modules and other devices of a parallel computer is the Interconnection Network. Solution? Distributed computing has become very popular as it provides a means to overcome the limitations imposed by sequential computers. The performance of single processor system is limited by the underlying fabrication technology. The operation of this computer is sequential. In ordinary uniprocessor system there is one processor and one memory unit.

1 Chapter 01 Intersystem Communications visit: Integrative Programming and Technologies 1Ģ Outlines Architectures for integrating systems Web Services and Middleware Network Programming Message and queuing services Low level data communications Integrative Programming and Technologies 2ģ Intersystem Communication.

Intersystem backbone definition