Page 1 Building Reliable Component-based Systems Chapter 12 - The Koala Component Model Chapter 12 The Koala Component Model

Page 2 Building Reliable Component-based Systems Chapter 12 - The Koala Component Model Overview qRequirements for Koala qKoala Interfaces qBinding, Gluing and Switches qThe Product Line Architecture qManaging Versions and Variants qSubtyping qSummary

Page 3 Building Reliable Component-based Systems Chapter 12 - The Koala Component Model Koala qKoala is l architectural description language l component model for development of embedded software for consumer electronics products. qIs used to build a large diversity of products from a repository of components.

Page 4 Building Reliable Component-based Systems Chapter 12 - The Koala Component Model Requirements for Koala qOriginal requirements: l Devise a technique with which components can be ‘freely’ composed into products. l The technique must work in resource-constrained environments. l Make the product architectures as explicit as possible. qAdditional requirements: l Let components make as few assumptions as possible about their environment. l Allow for parameterized components that are as efficient as dedicated components. l Allow for various ways of connecting components.

Page 5 Building Reliable Component-based Systems Chapter 12 - The Koala Component Model Koala Interfaces qProvide: l Like interfaces in COM and java. qRequire: l Communication with components environment. qMultiple: l Handle evolution and diversity. qOptional: l Fine tune.

Page 6 Building Reliable Component-based Systems Chapter 12 - The Koala Component Model Binding and Bind Time in Koala qBasic binding scheme: l Usage of symbolic names. l Architectural description language. l Compiler generates #define. qCan be used as long as we build closed systems.

Page 7 Building Reliable Component-based Systems Chapter 12 - The Koala Component Model Principle of Binding A B P A B’ P’

Page 8 Building Reliable Component-based Systems Chapter 12 - The Koala Component Model Koala Components qKoala component: l Implementation in C. l Component definition. qKoala configuration: l List of components. l Top-level component. qKoala component definition: l Describes template for instantiating component. l Resembles a class in java.

Page 9 Building Reliable Component-based Systems Chapter 12 - The Koala Component Model C C2C2 C1C1 C3C3 ms A Koala Component A module A switch Interfaces Subcomponent

Page 10 Building Reliable Component-based Systems Chapter 12 - The Koala Component Model Composing Koala Components qConnect: l Requires interfaces to provides interfaces; l Provides interfaces to provides interfaces; l Requires interfaces to requires interfaces. qDoes not fit? l Connect a wider type. l ’Normal’ glue code. l Switch.

Page 11 Building Reliable Component-based Systems Chapter 12 - The Koala Component Model Architectural Rules qInitialization l Initialization interface qMultithreading l Pumps qNotifications l Large number of asynchronous activities

Page 12 Building Reliable Component-based Systems Chapter 12 - The Koala Component Model Overall Architecture qSeparated into three layers: l Computing platform l Audio/video/data platform l Service and application qLayer contains a set of subsystems qSubsystems contain may components

Page 13 Building Reliable Component-based Systems Chapter 12 - The Koala Component Model Computing Hardware tvplf infra A/V Platform API uims txt epg deal fact Computing Platform tvsvc apps Computing Platform API Audio / Video Hardware A/V and Data Platform Applications & Services Product Line Architecture

Page 14 Building Reliable Component-based Systems Chapter 12 - The Koala Component Model Managing Versions and Variants qDiversity in a product line should not be handled by a CM system, because: l It keeps diversity outside scope of the architects and, l CM systems only handle compile-time variation. qCM used for: l Maintaining full version history. l Temporary branches. l Safeguarding product in final testing phase. qKoala used for permanent diversity.

Page 15 Building Reliable Component-based Systems Chapter 12 - The Koala Component Model Summary qInterfaces qBinding and bindtimes qComponents composition qArchitectural rules qOverall architecture qVersion management