Page 1 Building Reliable Component-based Systems Chapter 17 - Architectural Support for Reuse Chapter 17 Architectural Support for Reuse

Page 2 Building Reliable Component-based Systems Chapter 17 - Architectural Support for Reuse Overview qIndustrial Automation Systems qThe Motivation for a Platform q The Architecture q Developing a Domain Specific Application

Page 3 Building Reliable Component-based Systems Chapter 17 - Architectural Support for Reuse Industrial Automation Systems q Highly specialized, independent, and incompatible hardware and software system solutions. qA flexible combination of basic hardware and software components, communications infrastructure, and application components.

Page 4 Building Reliable Component-based Systems Chapter 17 - Architectural Support for Reuse The 6-layer Model of a Technical Process

Page 5 Building Reliable Component-based Systems Chapter 17 - Architectural Support for Reuse The Motivation for a Platform qEnvisioned seamless link between front-end business processes and plant control processes: l Motivations for a large global company to invest into the development of a “single” platform. l Avoidance of parallel developments in different business segments. l Harmonization of the diversity of ‘legacy’ automation platforms acquired through company mergers or resulting from previous parallel developments. l Adoption of product line business strategies (i.e. pursuing a system family concept both within and across vertical market segments). Implicit expectation of a reuse payoff.

Page 6 Building Reliable Component-based Systems Chapter 17 - Architectural Support for Reuse The Architecture q AspectObject, Object Type, Aspect and Aspect Type. qAspect System l A collection of Aspect Types for a certain context or purpose. l Domain-related reuse. q AspectSystemObject l Some Aspect-specific software is needed. l (binary) Software component; Microsoft COM component following specific rules l The basic set of ASOs distributed with the AIP contains functionality for alarming, event handling etc.

Page 7 Building Reliable Component-based Systems Chapter 17 - Architectural Support for Reuse AspectObjects  The most central type of entity in the model  AspectObjects model physical objects E.g. a specific valve in a dairy (“FIC 201 Valve”)  Does not contain any data Related data is carried by its Aspects AspectObject Aspect

Page 8 Building Reliable Component-based Systems Chapter 17 - Architectural Support for Reuse Aspect  Encapsulates a subset of the data related to an AspectObject Different types of electronic information (e.g. documents)

Page 9 Building Reliable Component-based Systems Chapter 17 - Architectural Support for Reuse Aspect Types  Defines how the data in an Aspect is used In a “Mechanical Drawing” Aspect, the data is opened with AutoCad In a “Maintenance Instructions” Aspect, the data is opened with Acrobat Reader  Reuse!

Page 10 Building Reliable Component-based Systems Chapter 17 - Architectural Support for Reuse Aspect Types, cont.

Page 11 Building Reliable Component-based Systems Chapter 17 - Architectural Support for Reuse Object Types  Models the type of an AspectObject The type of “FIC 201” is “Valve”  Defines what Aspect Types an AspectObject can have A “Valve” can have a “Mechanical drawing” etc.  Reuse!

Page 12 Building Reliable Component-based Systems Chapter 17 - Architectural Support for Reuse Object Types, cont.

Page 13 Building Reliable Component-based Systems Chapter 17 - Architectural Support for Reuse Structures  Models a structure Location structure Functional structure Batch structure...  Typically, each AspectObject is part of several structures

Page 14 Building Reliable Component-based Systems Chapter 17 - Architectural Support for Reuse Structures, cont.

Page 15 Building Reliable Component-based Systems Chapter 17 - Architectural Support for Reuse Structures, cont.  Location structure Enables browsing through the physical layout See what valves are physically connected to a pipe  Functional structure Enables browsing through the functional layout See what control units are connected to a valve

Page 16 Building Reliable Component-based Systems Chapter 17 - Architectural Support for Reuse Physical view  Client-server system  Freedom to choose number of servers Scalability Reliability  Freedom to choose number of services

Page 17 Building Reliable Component-based Systems Chapter 17 - Architectural Support for Reuse Physical view, cont.

Page 18 Building Reliable Component-based Systems Chapter 17 - Architectural Support for Reuse Developing a Domain Specific Application qJacobson et al. have introduced the distinction between an application system and a component system: l Reusing a single component is usually insufficient. l Requires the reuse of a set of components. l A set of components must be reused to obtain the alarm handling functionality.

Page 19 Building Reliable Component-based Systems Chapter 17 - Architectural Support for Reuse 4-Layer Representation qApplication system layer: l Offers a coherent set of use cases to some end users. q The business-specific: l Layer several component systems used by the application engineer. q The middleware layer: l Independent of particular types of business l GUI builders, database management systems, etc. q The system software layer: l Operating systems. l Indistinct boundaries between itself and middleware.

Page 20 Building Reliable Component-based Systems Chapter 17 - Architectural Support for Reuse AIP Reuse Hierarchy W2k AIP base infrastructure AIP base ASOs project specific ASOs AIP base Services project specific Services AIP built-in admin Aspect Types project specific Aspect Types AIP built-in general- purpose Aspect Types AIP built-in admin Object Types project specific Object Types AIP built-in general- purpose Object Types domain specific Aspect Types domain specific Object Types domain specific templates and patterns project specific templates and patterns enablers engineering guidelines and tools AIP library concept AIP export/import OT inheritance AIP export/import AT inheritance COM VC++ configuration 3 rd party applications

Page 21 Building Reliable Component-based Systems Chapter 17 - Architectural Support for Reuse Some Words of Caution qPossible risks: l Only relying on a platform, not having a reuse-driven process or product line practice with a top-down and planned approach to reuse will not succeed. q Requirements management: l Requirements elicitation, prioritisation and trade-offs across products, domains, and organizational units are extremely complex. l Bugs in a released version