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The dynamic reconfiguration package is composed of three sub-packages. The
reconfiguration decision making sub-package is responsible for receiving the event
notification and determining which reconfiguration actions are required to adapt
the system to the occurrence of that event. A group of reconfiguration actions
is sent to the dynamic configuration engine sub-package, which applies them with
the help of the dynamic dependency manager. To implement the dynamic dependency
manager, we intend to use the component configurator infrastructure described
in [6].
In this model, two types of dependencies are explored:
- Prerequisites necessary for loading an inert component into the
runtime system. They are usually expressed as dependencies on persistent hardware
and software components. A prerequisite list can contain three different kinds of
information: the nature of the hardware resources the component needs, the capacity
of the hardware resources it needs and the software services it requires.
- Dynamic dependencies between loaded components in a running
system. A component configurator manages the dependencies of each component.
The component configurator is responsible for storing the runtime dependencies
between a specific component and others system and application components.
By maintaining the dynamic dependencies between the components that compose the
application we can guarantee runtime consistency. For example, if one component
fails, the components that depends on it can be notified in order to promote
a graceful exit.
By maintaining an explicit representation of the prerequisites and
dynamic dependencies in the distributed system, the dynamic reconfiguration
package acquires the necessary knowledge to reconfigure the system in a safe
and consistent way.
Next: Approach to be Used
Up: Goal Statement
Previous: Event Detection and Notification
Francisco Jose da Silva e Silva
2001-09-24