Artifact: Platform Specific Model

The Platform Specific Model is an adaptation of a Platform Independent Model (PIM) for execution on a specific target through the selection of technologies, design solutions, or design patterns.

Domains: Architecture
Extends: Model

Purpose

The purpose of the Platform-Specific Model (PSM) is to provide an optimized, targeted implementation of a Platform Independent Model (PIM).

Relationships

Contained Artifacts	Design Collaboration
Roles	Responsible:	Modified By: Architect Software Modeler
Tasks	Input To: Optimize Class Optimize Collaboration Translate Verify Class Verify Collaboration	Output From: Optimize Class Optimize Collaboration Optimize Concurrency Architecture Optimize Dependability Architecture Optimize Deployment Architecture Optimize Distribution Architecture Optimize Secondary Architectural Views Optimize Subsystems and Component Architecture Select Special Needs Classes Verify Class Verify Collaboration

Description

Main Description	The PSM is a model of the system that contains both the essential elements from the PIM and technologies, design patterns, and design solutions meant to optimize the PSM. In the Harmony/Embedded process, design is all about optimization. While the PIM executes the required functionality of the system, it does so in an un-optimized fashion. Specific technologies, architectures, design patterns, and other design decisions are added to provide the PIM functional in a fashion optimized for the intended use and target platform(s).
Notation	The Unified Modeling Language (UML) is the primary language for the representation of models although other domain-specific representations (such as Fault Tree Analysis) are often used in conjunction with the UML.
Selected Representation	The most important diagrams from the UML are: class, state, and sequence diagrams. Other diagrams add value but virtually all systems can be specified and created from only these three basic types.

Key Considerations

The PSM must support the functionality of its parent PIM while at the same time making design and technology decisions that optimize its properties against various design criteria, including QoS.

Tailoring

Impact of not having	The PSM provides an optimized solution that meets the functional needs of the system, so not having a PSM means that while the basic functionality may be met, it is certainly likely to be un-optimized and may not meet the system's required QoS requirements.
Reasons for not needing	In early prototypes (builds) there is usually more emphasis on key concepts (analysis, requirements, and architecture concepts) while later prototypes focus more on fine-tuning, optimization, and deployment concerns. Thus, early prototypes may have very little optimization present.

More Information

Checklists	Activity Diagram Class Diagram PIM Review Platform Specific Model Scenario State Diagram
Concepts	Kinds of Models
Guidelines	Naming Conventions Producing the Platform Specific Model Scenario