Saturday, 29 August 2009

Open Distributed Processing

  • Among the various architectural approaches, a useful international standard, the Reference Model for Open Distributed Processing (RM-ODP), defines what information systems architecture means [ISO 1996].
  • RM-ODP defines five essential viewpoints for modeling systems architecture:
    • Enterprise viewpoint
    • Information viewpoint
    • Computational viewpoint
    • Engineering viewpoint
    • Technology viewpoint
  • The five viewpoints provide a comprehensive model of a single information system, with each viewpoint being a perspective on a single information system. The set of viewpoints is not closed, so that additional viewpoints can be added as the needs arise.
    • Another of their purposes is to provide information descriptions that address the questions and needs of particular stakeholders in the system.
    • By standardizing five viewpoints, RM-ODP is claiming that these five stakeholder perspectives are sufficient for resolving both business functionality and distributed systems issues in the architecture and design of information systems.
  • The enterprise viewpoint of the RM-ODP takes the perspective of a business model.
    • Managers and end users in the business environment should be able to understand the enterprise models readily.
    • The enterprise viewpoint ensures that business needs are satisfied through the architecture and provides a description that enables validation of these assertions with the end users.
  • The information viewpoint defines the universe of discourse in the information system.
    • The perspective is similar to the design information generated by a database modeler.
    • The information viewpoint is a logical representation of the data and processes on data in the information system.
    • The information viewpoint is an object-oriented logical model of the information assets in the business and how these assets are processed and manipulated.
  • The computational viewpoint partitions the system into software components that are capable of supporting distribution.
    • It takes the perspective of a designer of application program interfaces for component-ware.
    • The computational viewpoint defines the boundaries between the software elements in the information system.
    • Generally, these boundaries are the architectural controls that ensure that the system structure will embody the qualities of adaptability in management of complexity that are appropriate to meet changing business needs and incorporate the evolving commercial technology.
  • The engineering viewpoint of RM-ODP exposes the distributed nature of the system.
    • Its perspective is similar to that of an operating system engineer who is familiar with the protocol stacks and allocation issues necessary to define the distributed processing solutions for the information system.
  • The technology viewpoint defines the mappings between the engineering objects and other objects designed to specific standards and technologies including product selections.
    • The viewpoint is similar to that of a network engineer who is familiar with the commercially available protocol standards and products that are appropriate selections to configure the information system.


    The RM-ODP viewpoints enable the separation of concerns that divide the business and logical functionality of the system from the distributed computing and commercial technology decisions of the architecture.

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