A Platform Independent Model, or PIM, provides a technology-neutral logical model of a system. It sits between the conceptual architecture and one or more platform-specific models.
Within the FX Demo Reference Architecture, the PIM identifies architectural structures and obligations preserved across conforming implementations. These include node roles, topic concepts, information flows, metadata obligations, control-plane responsibilities, release constraints, jurisdictional constraints, evidence requirements, and behavioral obligations.
The PIM excludes programming languages, middleware platforms, databases, network transports, vendor products, deployment environments, generated artifact formats, and implementation repository structures. These concerns belong to a Platform Specific Model, implementation guidance, or implementation artifact.
model of a system that is independent of the features of any specific technological platform
Adapted from OMG Model Driven Architecture terminology.
A PIM defines architecture-level meaning, structure, and obligations independently of implementation technology.
In the FX Demo Reference Architecture, DDS domains, DDS topics, IDL definitions, generated types, QoS settings, OpenDDS configuration, adapters, code modules, repository structure, scripts, logs, build artifacts, containers, and deployment files are Platform Specific Model or implementation artifacts, not PIM artifacts.
A PIM specifies a policy decision function that determines whether information crosses a jurisdictional boundary and records evidence for the decision.
A Platform-Specific Model implements the policy decision function using selected technologies, such as DDS, IDL, OpenDDS, a graph database, a REST service, or other technologies.